Winter 2016 Issue by IGS Magazine

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The IGS Interview: Straight talking from Guus Boekhoudt Lisa under the glass slide

Schh... Miriam’s talking

Detroit, USA. 455 W For t Street, roupJJR Courtesy of SmithG

455 W Fort Street, Detroit, USA. Courtesy of SmithGroupJJR

Proven Performance that lasts

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A PIONEER IN SILICONE STRUCTURAL GLAZING Proven performing Silicone Solutions from Dow Corning: Yesterday, Today & Tomorrow.

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Dow Corning is a registered trademark of Dow Corning Corporation. The Corning portion of the Dow Corning trademark is a trademark of Corning Incorporated, used under license. Â© 2016 Dow Corning Corporation, a wholly owned subsidiary of The Dow Chemical Company. All rights reserved. Photos AV25876, AV25879, AV25510, AV25329, AV18144, AV17796 Form No. 62-1850-01

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Truth is stranger than ﬁction

s the year comes hurtling to a close I think it’s fair to say 2016 has been a tumultuous year. Every year is a busy one but this particular year has been one of the craziest for as long as I can remember. In January, David Cameron was sitting comfortably in a strong position as Prime Minister of the United Kingdom and to be fair, the people appeared to be warming to him as he was becoming more settled and accomplished as the UK Premier. He called a referendum and 5 months later he was gone. The people took the first chance they could to show their disapproval for politicians who “talk with forked tongue” and decided to turn their back on Europe and leave the European Union. All manner of speculation followed as to the type of people who voted for Brexit, old age pensioners living outside of London nostalgic for the heady days of the British Empire and signed up to the phrase made famous by George Bernard Shaw, “its a shame that youth is

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wasted on the young”. Some said it was a revenge vote because their region is completely disregarded as unimportant by parliament so therefore “I’ll show you”. The next day Cameron was gone and many of the people that voted for Brexit will not be here when the exodus comes around. Ex-Mayor of London Boris Johnson was hot favourite to slide seamlessly into the hot seat but got a knife in the back and a kick in the teeth from Michael Gove, then Gove got bitten by the black widow spider and was thrown out of parliament by the seat of his pants as Theresa May sat proudly on the Throne. Truth is stranger than fiction, if you’d seen these shenanigans in a film you wouldn’t have believed it.

The vast majority of the world outside of America expected the US would have it’s first female president in Hillary Clinton. It was inconceivable that Americans would vote for a racist, mysoginist, egotistical, obnoxious, baked bean coloured, sexual predator like Donald Trump as the 45th President of their country, but it is their country.....and they did. Women are now suspicious of men smelling of tic-tac, there’s a rumour that rape will be legal in the States from next year and the odds have been slashed on there being a war inside the next 12 months. Meanwhile for Hillary and for women the world over this is a major setback as it appears the glass ceiling now boasts Gorilla glass, laminated, strengthened and will remain firmly in place for some considerable time to come. Bring on 2017 but batten down the hatches dear readers, it promises to be a very exciting year.

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We enthusiastically throw Living Walls, Green Roofs and Photovoltaics at as much of the external facade as we possibly can though the return by way of kW Peak Performance is so negligible that it is hardly an incentive to the developer short of BREEAM and or LEED points.

MIRIAM WHITE Too often we limit our thinking about innovation to just product performance. We need to expand our deďŹ nition beyond the performance of our products to include novel ways of reducing waste in our processes, improving service to our customers, better managing inventory through the value chain, optimizing product portfolios, better utilization of existing assets and expanding our knowledge of glass applications..

GUUS BOEKHOUDT On the other hand, double curved glass is much more complex to produce. Flat glass is placed over custom-fabricated moulds (adaptive moulds are still not a working reality) and heated up to approximately 700Â°C. As glass slowly softens, gravity causes it to sag and take the shape of the mould supporting it. This method is slow, and sagging into the mould is not accurately controllable so it requires a good amount of trial and error to succeed.

AGNES KOLTAY

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Publisher’s blurb

70 78 98 116 intelligent glass solutions

DR.ANDREAS WOLF & DIPL.-ING.CHRISTOPH RECKNAGEL Using wind tunnel tests conducted in a Canadian lab, Gensler and structural engineer Thornton Tomasetti, reﬁned the tower’s form, which reduced building wind loads by 24%. The result is a lighter structure that saved $58 million in costly construction materials.

THE SHANGHAI TOWER Moving outward from the panel the next logical place to examine for the presence of unaccounted heat transfer pathways is within the frame components. In particular, at locations where lengthwise thermal gradients might be expected to occur as a result of insulation placement, the location of thermal breaks or as a result of the inherent geometry.

LARRY CARBERRY It’s quite easy to see – and feel – the improvements in glass performance, but is glass production also following suit? For example, the production process of ﬂoat glass involves running a furnace at 1,600 °C around the clock, 365 days a year. This not only consumes lots of energy, the nature of the process means that heat inevitably escapes the furnace. Industry players are taking decisive steps to address this waste heat and improve efﬁciency.

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C O N T E N T S Introduction 8

Sustainable solutions for the built environment, a collaborative approach Miriam White, BSW Land & Property Limited

Executive Boardroom Commentary

14 Integrated Facades: How technology development and building codes are shaping the future Helen Sanders, Sage Electrochromics 20 Itâ&#x20AC;&#x2122;s the economy smarty! Joachim Stoss, Edgetech THE BIG IGS INTERVIEW - Introducing Guus Boekhoudt 30 Straight talking! Guus Boekhoudt, Guardian Glass Industries

Amazing projects in glass 38 The OPUS at Business Bay, Dubai Agnes Koltay Agnes Koltay Facades, Dubai 46 The Zigzag Building London, facades acting as intermediate spaces Klaus Lother, Josef Gartner GmbH 60 Remembering Zaha. Projects for ZHA in Lusail City, Doha ZHA Architects 62 Preparing for the 25th Anniversary of GPD GPD Organising Committee

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64 Remembering glass technology live 2016 at glasstec in Dusseldorf Dipl.-Ing. Jutta Albus & Dipl.-Ing Johannes Pellkofer MBA Stuttgart University

C O N T E N T S 70 Proven Performance that lasts Dr.Andreas Wolf & Dipl.-Ing Christoph Recknagel Dow Corning 78 Sentryglas interlayer gets stuck into Shanghai Tower Kuraray/Trosifol 82 Silicones enabling crystal clear connections Valerie Hayez, Dow Corning Europe S.A

Gearing up for a 25th Anniversary i n Ta m p e r e 90 All glass house - A new space for living Philip Wilson Spatiale Limited 94 Attaching insulated glass to buildings, what are your options? Louis Moreau, AGNORA 98 A comparison of the thermal transmittance of curtain wall spandrel areas employing mineral wool and vacuum insulation panels by numerical modelling and experimental evaluation Lawrence Carberry, Dow Corning Inc. 116 See the possibilities - innovation in glass and glass manufacturing for a sustainable future Paul Anderson, Guardian Glass Industries The Paul Bastianen Column

78 L o n d o n

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The IGS Interview: Straight talking from Guus Boekhoudt Lisa under the glass slide

Schh... Miriam’s talking INTELLIGENT GLASS SOLUTIONS

Front cover Photo: The glass slide Design: Eckersley O’Callaghan/Cricursa Photo Supplied Courtesy of: Eckersley O’Callaghan Published by: Intelligent Publications Limited (IPL) ISSN: 1742-2396 Intelligent Glass Solutions Publisher: Nick Beaumont Accounts: Richard Marks Editor: Sean Peters Production Manager: Kath James

122 The World is on Fire!!! Paul Bastianen 128 Authors Details

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Intelligent Glass Solutions is a quarterly Publication.The annual subscription rates are£59 in the UK, £70 in Ireland and mainland Europe and £96 for the rest of the world. Email: nick@intelligentpublications.com Published by: Intelligent Publications Limited 3rd Floor, Omnibus House 39 - 41 North Road, London N7 9DP United Kingdom Tel: +44.207.607.9907 Email: nick@intelligentpublications.com Web: www.intelligentpublications.com

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Introduction

Sustainable Solutions for the Built Environment, a Collaborative Approach Miriam White, BSW Land and Property Limited

Now, more than any other time in my 30 years of practicing architecture and recently as a developer, I am acutely aware of my responsibility to deliver sustainable building solutions. Graduating from Auckland School of Architecture with Distinction in 1985 gives one a false sense of security visa-vis oneâ&#x20AC;&#x2122;s talent and skill set to enter into the profession and immediately start designing and delivering responsible architecture. No matter what the profession of choice, one is never adequately equipped to enter directly into the operation room or delivery suite nor does one appreciate that your education is just about to begin and the rules of engagement will change and develop many times within an architects relatively short career.

intelligent glass solutions

Introduction

Climate change has perhaps been the most significant driving force in effecting the way we now conceive, specify, and deliver cities in this century. There was a time, I recall, when the word sustainability was not referred to in the design brief or specification, but a solution that came about through particular need, perhaps say a Community Project where by the local residents pull together resources in the form of land and labour in order to deliver a nonfunded facility. Sustainable design and the construction process in this circumstance is the resultant of scarce funds and resources, as such a sustainable solution resulted more by default rather than desire. In my career I have had the privilege to work on large scale projects covering most sectors, and have witnessed a 180-degree turnaround to the approach of sustainability from little or no understanding or willingness to acknowledge climate change and our responsibility, given the construction industry is a significant contributor

intelligent glass solutions

Introduction

intelligent glass solutions

Introduction

of excessive carbon emissions to a responsible, embodied approach to design for a sustainable future. No one architect or engineer has the skill sets to fully comprehend and interpret this complex issue. Only through cross-disciplinary collaboration between designers, extending out to contractors, manufacturers and developers is the solution to unlocking the complex issues of sustainability. A shopping list is where we usually start, and it goes without saying that we seldom deliver 100% of the shopping list. Our city sites are constrained by the very nature of the dense urban environment that hinders access, and as such the window of time to deliver is fraught with conditions. Our rural green or industrial brown field sites are quite often devoid of basic infrastructure to support a quality development. Both scenarios require a disproportionate amount of equity before we can even get started to tick the boxes on our renewables shopping list. I recently had the privilege to run the architectural design team for a joint public services training college with its 100 or so buildings covering 210 acres of Green Field land. The engineer’s analysis of the renewable energy identified 30% renewable energy target could be met through on site biomass heating, and supplemented through the use

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of wind turbines and on and off site biomass fuel production, thus achieving over all carbon neutrality for the site. Further innovations including ground source heat pumps and ground water cooling added to support low energy consumption that further diminished the site dependency on external resources. Needless to say, this type of project is not common place in my portfolio though it set the bar high for those that followed. In recent inner city developments, the shopping lists are shorter and even harder to achieve. We enthusiastically throw Living Walls, Green Roofs and Photovoltaics at as much of the external facade as we possibly can, though the return by way of kW Peak Performance is so negligible that it is hardly an incentive to the developer short of BREEAM and or LEED points. Our engineers come up with superb solutions for CHP which put pressure on NETT to GROSS coupled with Ground Heat Rejection which is costly and impacts the front end construction programme. Further to my point above that a collaborative approach is a prerequisite. During my employment with Foster and Partners we delivered circa 5,400m2, an unprecedented quantum of accessible Green Roofs and circa 1,500m2 of Photovoltaics atop Allen and Overy’s Offices at Bishop Square. No doubt a true success storey in Planning Terms vis-à-vis the quantum of Nett Lettable Area and a compelling landscape contribution to London, though one does wonder how

much contribution to the grid we really made. Back then the Government would contribute circa 40% to the Capital Cost of supply and installation of PV’s so long as we achieved a min 82kW at Peak. Such grants I have not experienced since, in support of such large quanta of renewables. We have only our Local Legislative targets. Acting as CMT at Perkins + Will for Quadrant Estates the Moorgate Exchange Commercial Offices project designed by HKR Architects, we delivered an inclined green roof oriented to the western sun and viewed by the Barbican residents. A living wall incorporating numerous indigenous plant species harbouring natural habitat for wild life. A maintenance issue was always understood though worth it to see the results in townscape terms and occupier experience. As per the previous example, I wonder today how much we actually contributed to the reduction of Carbon Emissions and could we have done more?

Miriam has practiced Architecture for some 30 years in NZ, HK, UK and the UAE for international architectural companies including Foster and Partners, RVA, Perkins + Will. She continues to consult providing the full range of architectural services and has recently co-founded a development company BSW Land and Property Limited. BSW current projects include various UK PRS and Hotel Developments.

Advance information on BAU 2017 in Munich

“Big in Detail” is sedak’s motto at the BAU 2017. The cold-bent, multiple laminate shows the lamination capabilities of the glass manufacturer. Photo: sedak GmbH & Co. KG | René Müller

Big in Detail BAU 2017: sedak presents capabilities for safety and insulating glass / hall C2, stand 100 sedak stands for oversize insulating and safety glass up to 16 m in premium quality. Since „big” is not only a question of dimensions, the glass manufacturer from Gersthofen focuses on perfection in detail at the BAU 2017. What that means for glass, sedak shows with four large exhibits in hall C2, stand 100: an insulating glass unit with a unique quality of the edge seal produced in a fully automated way, a highresolution ceramic-ink digital print with a backlit image, a part of a glass-fin façade with just a few connection elements, and finally a coldbent triple laminate. The latter was produced for the shipbuilding sector and has already been installed e.g. as a 10-layer laminate. The triple unit caught a lot of attention at this year’s

glasstec. With those exhibits in special size, sedak impressively underlines its pioneering role arising from a ten-year experience in glass technology for oversize and special glass. sedak, the leading innovator for oversize formats and customized solutions, has established a high level of know-how in manufacturing large glass. In many cases, that competence can be seen in details. Only if you find path-breaking solutions for the small things, the big things will work. To prove that, sedak exhibits glass at the BAU 2017 according to the motto “Big in Detail” using four exhibits to explain the know-how behind it.

Glass in a key position Maximum transparency can be achieved as soon as the façade’s supporting structure is out of glass. Exemplarily, sedak shows this modern architecture with two façade elements connected to a glass fin. Both the 6 m high fin and the glass panes are fascinating multiple laminates fabricated with an edge quality characteristic for sedak. The toggle system with its minimalistic connection elements, is of technical brilliance. The parts have been laminated between the laminates’ layers in a highly precise way so that the elements are almost invisible. This unique technology opens new ways of designing facades. sedak has used that technique e.g. for the Apple Cube in New

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Advance information on BAU 2017 in Munich

York, the Skywalk in Dubai as well as for several glass-fin façades of premium stores. The glass manufacturer produces the supporting glass fins with fixing elements like metal shoes. That allows for a simple installation at the site. Large print with high level of detail With a 5.5 m long and 2.6 m high glass pane, sedak shows not only its motto „Big in Detail” but also its printing capability. Since 2014, sedak has operated a ceramic-ink digital printer for 16 m long glass with a resolution of 720 dpi. That enables sedak to demonstrate a back-lit, printed glass that impresses with excellent color brilliance and a very high level of detail. By firing the colors in the tempering furnace, they are permanently bonded to the surface and the print is extremely resistant. The glass produced for the BAU 2017 has been printed with a photo showing how an insulating glass unit is being siliconized on the world’s largest insulating glass line in sedak’s production hall. Curved with precision Cold-bending during lamination enables sedak to produce curved glass of very high quality. During the lamination process in the autoclave, only the foils between the glass layers melt. After the cooling the glass therefore appears in perfect quality without any roller waves or other defects. Cold-bent multiple laminates redefine the possibilities of glass processing. The fabrication requires an absolute precision and dimensional accuracy. sedak exemplarily presents a 20 mm thick triple laminate in the dimensions 1.28 m x 3.68 m just as it has been installed in a mega yacht. The bending line with a rise of 120 mm is diagonal so that the glass pane nestles perfectly against the ship’s spherically shaped hull. Besides the high demand for precision, the glass panes have to pass leak tests for the usage under water. But the architectural sector also benefits from cold-bent glass since it allows for diverse designing possibilities. Automated perfection up to 15m sedak produces double and triple insulating glass units with a length up to 15 m on the fully automated insulating glass line. The industrial manufacture ensures that all details are executed correctly. An exact positioning of the spacer and a precise siliconizing is guaranteed even with non-rectangular glass. Furthermore, the IGU line has reduced the production time significantly so that large formats are now

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fabricated more economically. As an example of a highly precise production of oversize glass units, sedak showcases a 2.800 mm wide, 4.000 mm high, and 600 mm thick triple insulating glass unit that also consists a laminate. For the highest quality requirements and a uniform and exact appearance, the coated glass pane has a printed edge. Innovation leadership – forward thinking sedak does not only show big formats but also that its big in quality. In particular with special constructions, the glass manufacturer demonstrates its solution-oriented competence – always with automated precision. For its self-conception as a leading innovator, sedak has pushed the production automation further with new technologies and machines during the last two years. And also the logistic has been developed. sedak now has the world’s largest inloader that transports glass up to 16 m including the glass rack. Due to its refined interior concept, no escort vehicle is required. A crane or a glass vacuum lifter for a time-consuming unloading is not necessary anymore.

For more information please contact: sedak GmbH & Co. KG Tatjana Vinkovic Phone.: +49(0)821/2494-823 Fax: +49(0)821/2494-777 Email: tatjana.vinkovic@sedak.com

sedak GmbH & Co. KG Leading glass sedak, the glass manufacturer in Gersthofen, Germany, was founded in 2007. With its 150 employees, the world’s leading glass fabricator produces insulating and safety glass in dimensions up to 3.2m x 16m: processed, tempered, laminated, printed, coated, and cold bent. The core capabilities are the lamination of glass, edging, and the company’s know-how of producing glass components with additional functional and decorative elements. sedak’s production has been optimized for extraordinary glass sizes; the level of automation for such glass dimensions is unique. All finishing steps are handled in-house e.g. with the new, fully automated insulating glass line. As a full supplier for large-size glass units, sedak sees itself as a partner for architects, designers, and façade constructors. Outstanding references are for example the Apple Cube and the Lincoln Center Canopies in New York, the Städel Museum in Frankfurt, and the Tottenham Court Road Station in London. Applications • glass façades • glass roofs • glass stairs • glass balustrades • ship building • safety glazing • all-glass constructions • interior design • costum-made glass units

pr nord. neue kommunikation. Kerstin Ahlburg Phone.: +49(0)531/70101-0 Fax: Fax: +49(0)531/70101-50 Email: k.ahlburg@pr-nord.de

Executive Boardroom Commentary

INTEGRATED FAĂ&#x2021;ADES: HOW TECHNOLOGY DEVELOPMENT AND BUILDING CODES ARE SHAPING THE FUTURE Helen Sanders, PhD SAGE Electrochromics, Faribault MN Pekka Hakkarainen, PhD Lutron Electronics, Coopersburg PA

ABSTRACT Improving energy efficiency in buildings is a global objective. The US government has a goal of making buildings 50% more energy efficient in 2013 compared to 2004 standards and a push to net-zero, or near net-zero, energy buildings in 2030. The European goals are even more stringent. In addition, sustainable design standards, such as USGBCâ&#x20AC;&#x2122;s LEED standard, BREEAM, ASHRAE 189.1 and the international Green Construction Code, require provision of daylighting and views as well as high energy efficiency and a comfortable environment. These requirements can be contradictory to each other because providing sufficient useful daylight through glazed areas often means uncomfortable glare and heat and increased building energy use. The need to provide dynamic control for light and heat, and to harvest daylight using lighting controls, is critical in minimizing the trade-offs between providing daylighting and views and energy efficiency. This paper will review recent advances in envelope and daylighting technology and how through integration they can provide a solution that has significant impact on getting to net zero buildings as well as on providing comfortable, well daylit, spaces.

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Executive Boardroom Commentary

Introduction – Daylighting and Views Human development has for millennia involved bringing light into shelters, and until fairly recently the only tools were daylight and fire. This was expressed well by John Pierson in an article in the Wall Street Journal [1] when he observed that “Ever since the first cave people crept indoors for safety, humans have sought to bring sunlight in from the outside.” Since then, the positive health and wellbeing benefits of daylight to entrain our circadian rhythms have been proven and well documented [2]. It is, therefore, understandable that we crave for daylight in our buildings, and perform best when it is given to us, whether we are performing office tasks, factory work, school work, shopping (well, we buy more!), or recuperating in a hospital. The challenge of 21st century building design is to attain a good balance between energy efficiency, human comfort and access to daylight and views. For example, a number of LEED certified buildings, while providing good access to views have no better energy performance than non LEED certified buildings, and with large expanses of glass have the potential to cause significant thermal and visual discomfort if there is insufficient solar control and a planned dynamic response for glare. Any two of the above can be relatively straightforward to achieve, but achieving all three is significantly more challenging and requires the help of technology developments.

Energy Benefits of Integrated Façades The energy efficiency of a building is largely dependent on the design of the building envelope, or façade. Energy can be transported across the building envelope by three different physical mechanisms. These are (1) conductive transport (2) radiative energy gain or loss, and (3) convective heat loss or gain, which occurs when the building envelope is fairly open or leaky. In this paper we focus on contributions from the first two physical mechanisms. While the third continues to be important, it needs to be addressed by technologies that are beyond the scope of this paper. The pathway to net zero energy buildings has partly been defined already by U.S. Department of Energy [3] using figure 1.

As can be seen, improvements in the building envelope performance are critical but are not sufficient. A significant portion of the energy savings occurs when those improvements are coupled with daylight responsive lighting controls. By using the term integrated insulating dynamic façades, or integrated façades for short, we refer to building design that contains the following 1) Effective daylighting design 2) Energy efficient fenestration with low u-factor and dynamic solar control, including thermal comfort for occupants, 3) Dimmable lighting control and 4) Dynamic glare control.

Figure 1 Integrated façades: Pathway to net-zero energy buildings. From Arasteh et al., LBNL report number 60049.

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Executive Boardroom Commentary

The impact of dimmable lighting controls, which is substantial, is also seen in the following figure (figure 2) that was the result of building simulations performed by researchers at Pennsylvania State University on the standard 3-story office building which is routinely used to verify the performance of the model building energy code ANSI/ASHRAE/IES Standard 90.1 [4].

optimum WWR can exceed 50%. In fact higher window to wall ratios can have building energy performance better than an opaque wall as long as the façade and interiors are designed well and effectively integrated into a good daylighting design. As an example of the performance an integrated facade can achieve, we refer to the paper published by Lawrence Berkeley National Laboratory regarding an installation in a conference room at the Department of Energy in Washington DC [5] (see figure 3).

Figure 2 Effect of lighting control on building energy savings. Information from a modeling study in 2010 by S. Treado, R. Mistrick et. al. at Penn State University

In this figure, we see that, for the case where no daylight responsive lighting controls are used, the total building energy consumption increases approximately linearly when the window-to-wall ratio (WWR), defined as the percentage of the exterior wall that is glazing, is increased. This makes sense, because the glazing area of the building is typically not as highly insulating as the opaque portion of the envelope, and in addition the windows permit the solar load on the building to increase if nothing is done about managing the overall energy balance. However, when you harvest the daylight and allow the electric lights to be dimmed or turned off, the energy usage of the building can actually go down as window area increases. At a certain window area, when there is sufficient daylight in the space and all the electric lights are turned off, additional window area will then cause loads to start to increase because of additional solar gains and conductive losses/gains. This explains the characteristic “U” shaped curve that you see in figure 2 when continuously dimming lighting controls are utilized. The exact depth and location of the minimum depends on several factors, such as climate zone, building orientation, fenestration performance, insulation of the opaque wall, depth of daylight penetration, interior design and reflectances, to mention some of the main factors. Ideally, each building is modeled to determine its optimum windowto-wall ratio. The better the daylighting design and fenestration performance the greater the optimum window area and the flatter the minimum is, such that increases in WWR over a wider range have little impact on the building energy. In a well-designed integrated façade the

Figure 3 Conference room in the DOE’s HQ in Washington DC which has been retrofitted with an integrated façade with EC glazing and dimmable lighting controls. Photo from reference [5].

In this case, the total lighting energy savings were 91% compared with the base design, and the total energy savings were near or over 40% compared with the base design. GOOD DAYLIGHT DESIGN Implementation of good daylight design is critical in achieving the optimum energy savings potential that integrated facades promise. A superior daylighting design achieves all of the following objectives: 1. Superior daylight performance by bringing as much daylight as possible deep into building to maximize daylight harvesting and providing views and “connection to outside”. 2. Occupant comfort by avoiding direct sunlight on critical visual tasks and other types of glare and avoiding thermal discomfort. 3. Superior energy performance by minimizing electric lighting energy use, controlling radiative gains and losses and controlling conductive gains and losses. Several techniques are known that help achieve the above objectives. For example, windows should be placed high along the wall to allow daylight to penetrate deeper into the space (e.g. using clerestory glazing)

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Executive Boardroom Commentary

etc! Such an example is shown in figure 5 which shows the lengths TSA officers are going to in order to deal with disabling glare on their computer screens at Midway airport. These “creative” glare control solutions generally remain in place long after the glare condition has abated and block daylight admission and any energy or human factors benefits that the original design intended. Other pitfalls related to glare should also be avoided. Especially critical is the avoidance of contrast glare such as is shown in figure 6 which demonstrates the unintended consequences of using small punched opening windows in a façade. The lights in the room have to be turned on or blinds pulled in order to counteract the contrast between the bright window openings and the dark walls, negating any energy savings and human factors benefit from harvesting daylight and also blocking the view to the outside. Figure 4 Good daylighting design with glass walled perimeter offices. Photo © Bruce Damonte. with light shelves and sloped ceilings. Skylights should be used whenever possible to get daylight into the core of the building. Perimeter offices as well as interior offices and conference rooms should have glass walls to permit daylight penetration further into the building, thus creating a larger daylighted perimeter zone. Good interior design consisting of high interior reflectances and low partition heights also promote good daylight design. An example of good design is shown in figure 4 above. In all cases, once you admit light into the building, the light must be effectively managed in order to avoid unwanted glare and uncomfortable heat. A dynamic response for glare is essential: Otherwise the performance of a, in other respects, great daylighting design will be negated by occupants who will be creative in developing their own methods for glare control such as cardboard, paper, or manual blinds

Figure 6 Excessive contrast glare caused by the use of small windows in a classroom. Photo courtesy of TRC (formerly Heschong Mahone Group).

TECHNOLOGY SOLUTIONS The availability of advanced façade technologies now provide designers with the tools to design façades that can meet the “green building design challenge” by providing the trifecta of high energy performance, daylighting and views without compromising occupant comfort. We will discuss here technology availability in the three key elements of a zero energy integrated façade; fenestration with both dynamic solar and glare control plus lighting controls.

Figure 5 An example of the solutions occupants will create if there is not a planned dynamic response for glare. Security checkpoint at Chicago Midway Airport, where bins have been balanced on the horizontal mullions of the curtainwall to block the glare.

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Dynamic solar and glare control solutions: There are two distinct ways that dynamic solar control can be provided to fenestration, either through motorized moveable exterior louver systems (including automated venetian blinds inside a double skin wall) or through the use of dynamic glazing. There are many automated exterior systems that have been developed and which have been utilized in European markets for a number of years. Whilst exterior systems do a good job of modulating the solar gains, they interrupt the view, cannot be

Executive Boardroom Commentary

used in certain weather conditions and require on-going maintenance. The main type of dynamic glazing is electrochromic (EC) glazing which has been commercially available for over ten years. Electrochromic glazing provides both dynamic solar control and dynamic glare control with no moving parts. Significant developments for EC glazing have been made in the past few years which have provided increased flexibility for designers. The most important of these include increased size availability (up to 5’x10’), increased manufacturing volume availability, availability of a range of colors that architects can choose from to match their project color aesthetic (see figure 7) and the ability to control up to three different areas of a single EC pane as different segments (see figure 8).

the EC within a pane, optimized performance across multiple dimensions can be achieved as well as the architect’s goal of reducing the number of mullions in the framing system.

FIgure 9: Dynamic control of glare using automated interior shades. Direct sun penetration is typically limited to a set distance from the window. Photograph © Barry Halkin Photography.

Figure 7 Examples of different exterior color aesthetics in EC glazing now available (from top left to bottom right – Clear, Gray, Green and Blue).

Dynamic glare control can also be achieved with the use of automated interior shading systems. They typically track the location of the sun in the sky and the shades are deployed when the sun is incident of the façade to limit the direct sun penetration to a predetermined distance along the floor from the window wall. A large range of fabric choices are available. The most suitable glare control fabrics have an openness factor of approximately 1%. Light blocking fabrics are also available when that is desired. Figure 9 gives an example of dynamic glare control with an interior shading system. As part of an integrated façade, this solution is normally used in conjunction with exterior shading for solar control.

Lighting control solutions: Recent developments for lighting controls include (1) standards for dimming fluorescent lamps; and (2) wireless lighting control solutions motivated by a reduction in the number of new construction projects and an increased importance of improving the energy performance of existing buildings.

Figure 8 An example of one of the new advances in electrochromic glazing: In-pane zoning. Photo courtesy of SAGE Electrochromics, Inc.

The lighting industry in the US agreed in 2011[6] on the electrode heating requirements for fluorescent lamps when under dimming conditions. This means that the most common commercially used light sources and the dimming ballasts that operate them are standardized and therefore their performance in installations will no longer be dependent on the specific lamps and ballasts.

This latter feature is essential in floor to ceiling glass to provide for effective co-optimization of glare control, light color quality, daylight admission and energy performance. For effective glare control, the EC glass needs to be fully tinted to 1% visible light transmittance, yet if the whole façade is at 1%T, there will be insufficient daylight admission, the lights will have to be turned on and the light color quality will suffer. With the ability to zone

Wireless lighting control and window shade control solutions are now well established for applications in commercial buildings. They greatly reduce the labor costs for building renovations and retrofits, making it practical to have automated daylighting systems that use continuously dimmable lighting controls and automated shade controls in these applications.

intelligent glass solutions

Executive Boardroom Commentary

Even though the model energy codes have not yet reached a point where they are requiring fully integrated faรงades as described herein, they do now recognize the use of dynamic glazing and provide interpretation language for the code official when such products are used. In the green codes such as ANSI/ASHRAE/USGBC/IES Standard 189.1 and the International Green Construction Code (IgCC), dynamic glazing is allowed as an alternative to the requirement for horizontal exterior static shading.

Figure 10 Dimming control gives good energy performance even in an average building with poor daylight design. Even at 40% window area energy performance is the same or better than the windowless building. If the prototype building had a larger and better daylit perimeter zone with dynamic solar control the optimum window to wall ratio would be significantly higher than shown here.

Building Code Development The developments of minimum building codes, such as ANSI/ASHRAE/IES Standard 90.1 or the International Energy Conservation Code (IECC), have not sufficiently addressed the challenge of providing energy efficient buildings whilst also promoting good daylighting design, views and occupant comfort expressed above. The general direction in minimum building codes is to reduce the window-to-wall ratio (WWR) as far as possible, in spite of the evidence that dynamic faรงades improve the performance of the buildings considerably. In ANSI/AHSRAE/IES Standard 90.1-2013 prescriptive compliance path, the maximum WWR is 40%, while in the International Energy Conservation Code (IECC-2015) it is 30%, with a provision for 40% when using daylight responsive lighting controls. Modeling studies using minimally code compliant buildings do indeed show that the energy efficiency improves with decreasing window size in almost all climate zones. Primarily this is because minimally compliant designs feature neither good daylighting design nor the best performing light dimming systems.

In order to continue to increase the stringency of building energy codes without compromising the quality of the space for the occupants a new look at how codes are developed is required. For example, finding ways to collaborate across the typical silos of lighting and envelope to create combined requirements that promote better daylighting designs without continuing down the path of reducing window area is important. Also, as we know, any good daylighting design can be negated by poor interior design choices and lack of a dynamic response for glare. Interior finishes is currently outside the scope of building energy codes and so an examination of how we can include such requirements in the scope would provide an opportunity for ensuring the anticipated energy savings are actually captured when the building is completed. Conclusions Dynamic integrated faรงades are the way of the future for high performance building design. These designs depend on high performance fenestration with low U-factor and dynamic solar control together with a dynamic response for glare control and continuously dimmable electric lighting control. No other solution will get us to (near) net-zero energy buildings nor provide the occupant wellbeing and comfort and design flexibility that architects and building owners desire. There are a range of proven commercially available solutions that provide designers with the tools that they need to meet the green building challenge and to deliver low energy buildings which have good access to natural daylight and views and yet which also provide good occupant visual and thermal comfort.

Good energy performance can be achieved even in an average building design when using high performance dimmable lighting controls, as shown in figure 10[7]. The building models used in this study were the same medium office building models used by Penn State researchers (see figure 2), representing average building design.

However, the current minimum building codes do not encourage designs towards this goal with their prescriptive paths. They set limits to the window-to-wall ratio primarily because minimally compliant buildings increase energy use as the window-to-wall ratio increases in almost all climate zones. But the electric lighting energy use in buildings with completely opaque walls will be too high to support net-zero energy goal and building owners and occupiers will simply not accept the design of window-less (or very low window area) buildings.

The results in figure 10 are from simulations performed by researchers from the Pacific Northwest National Laboratory and from the HeschongMahone Group (now part of TRC Engineering Services), presented to the ASHRAE Standards Standing Project Committee 90.1 in January 2012. The main changes, compared to minimally code compliant design, are somewhat better window performance with higher visible light transmission (although no dynamic solar control), daylighted areas around the entire perimeter of the building, and continuously dimmable lighting controls including lights being turned to off when sufficient daylight is available.

Therefore something about our building energy codes has to change. In addition to recognizing the need for dynamic glare and solar control in code development, more cross-silo integration to promote the use of best practices in daylight design in the minimally compliant buildings is going to be necessary if we are going to maintain buildings that are people friendly as well as energy efficient. Another sensible change would be a change in scope that would give code officials jurisdiction over interior design in the first year of occupancy. These changes would enable many energy efficient changes to minimally compliant buildings. And the occupants would be happier, more motivated and more productive, too!

intelligent glass solutions

Executive Boardroom Commentary

Joachim Stoss Edgetech

intelligent glass solutions

Executive Boardroom Commentary

Itâ&#x20AC;&#x2122;s the economy, Smarty!

intelligent glass solutions

Executive Boardroom Commentary

In a manner that almost no other material matches, glass offers endless design options for modern facades. Triple insulating glass is increasingly installed to maximise the degree of energy efficiency of the building envelope. Thus the importance of the spacer in the insulating glass is also increasing and the focus is more upon productive, simply automated processing. Maximum economic efficiency is the order of the day for manufacturers of warm edge spacers such as Edgetech. In 2011 Edgetech Europe GmbH opened its production facility at its present location in Heinsberg, Germany. The flexible, foam-based Super Spacer® systems are manufactured here, in addition to the sites in the UK and the USA. They act as an energy efficient warm edge in insulating glass windows, reduce the external energy loss to a great extent, largely prevent the formation of condensation and also contribute towards the extended service life of a window. Joachim Stoss, who has been Managing Director at the company since 2013, draws a very positive balance when looking back on the past five years. “When we came to Germany with our own production facilities Super Spacer® were in vogue, now we are the trendsetters where warm edge technology is concerned” explains Joachim Stoss, and this is something that has also been impressively underlined by the figures. The annual, global output of all three production plants amounts to more than 300 million metres on average. Numerous major manufacturers of insulating glass upgraded their automated systems for the Super Spacer® application. Economic efficiency coupled with a discreet appearance Joachim Stoss puts this rapid success down to two main factors: Achieving the maximum levels of economic efficiency in the production of the insulating glass units as well as the high-precision manual and automatic processing that meets even the most demanding requirements upon the energy efficiency, appearance and durability. In particular, the formability of the flexible Super Spacer® made of silicone foam provides considerable advantages for glazing that exceeds the standard sizes as demonstrated by numerous innovative flagship projects. Exclusive Kompassen shopping mall in Sweden In the case of the Kompassen shopping centre the facade in particular was intended to become a hallmark that is visible from afar of the new mall. However, the team of Ågren Arkitekter did have to meet one condition: only tried and tested and demonstrably durable materials may be used for the construction work as obviously when constructing a shopping centre the balancing act between aesthetics, functionality and economy is the thing that must be pulled off first and foremost. Architect Magnus Åhs knew what effect he wanted to achieve with his design, but his vision of sunlight reflected and refracted in the facade was only realised through a concerted approach of all the companies involved in this project.

intelligent glass solutions

Executive Boardroom Commentary

intelligent glass solutions

Executive Boardroom Commentary

intelligent glass solutions

Executive Boardroom Commentary

Swedish glass tradition meets innovation The Swedish building envelope specialist, Skandinaviska Glassystem, consulted the glass artist Sofia Bergman and the idea of applying amber cast glass in an asymmetrical pyramid shape onto the facade was born. The cast glass parts were manufactured in the glassworks of Målerås Glasbruk that is situated in the middle of the famous “Kingdom of Crystal” in Småland. Each of the total of 5,700 glass pyramids has a base area of 20 by 20 centimetres and weighs more than three kilograms. In a similar way to a conventional insulating glass unit they are applied to the mirror glass that is secured invisibly from the outside to the sandwich facade. The perfect symbiosis between Swedish glass art and state-of-the-art flat glass technology can be seen in the finished facade. However the successful final results could certainly not have really been anticipated at the start of the project and hence the responsible project manager at Skandinaviska Glassystem, Erik Stening, found appreciative words for the teamwork: “Only the close cooperation of all the parties involved facilitated the perfect matching of each individual component to form a unique overall work of art which we can all rightly be proud of.” Hence Edgetech was, for instance, proposed as a partner by the sealing specialist Sika. The Super Spacer® TriSealTM. Premium Plus was ideally suited to the manufacture of the small mirror glass units, supplied by KS Glas. “Windows with such small dimensions cannot be manufactured economically with conventional spacers made of aluminium or plastic,” explains the engineering specialist of the Heinsberg-based company, Christoph Rubel. Edgetech’s triple seal system is already equipped with a Polyisobutylene seal for easy manual processing at the factory. The clean and precise all-round application is performed quickly and easily with matching tools without the need for time-consuming bending or cutting. The three-step application process is completed after the pressing of the two panes of glass and the application of the outer sealing material. Sedak processes Super Spacer® for large-format production Also where the automated production is concerned no additional process steps are required during the processing of Super Spacer® spacers. Rigid spacers on the other hand require up to seven process steps. Productivity is therefore an important aspect that contributes towards the profitability of an insulating glass production line and was also one of the main reasons for the southern German glass refiner Sedak to also integrate Edgetech within the new insulating glass production line for the fully automated production of double or triple insulating glass in large formats of up to 15 metres in length in 2015. No other manufacturer is currently able to automatically produce glass units in this size without manual assembly. The efficiency of the new production plant in the Bavarian town of Gersthofen is most impressive. Several days of manual work can

intelligent glass solutions

Executive Boardroom Commentary

be set against less than an hour of fully automated production. As is the case with many of its architectural projects, the specialists for oversized insulating and safety glass have also gone to the limits of what is physically and technologically possible with the new production plant. A glass element can weigh up to 7 tonnes. The load capacity of the machine amounts to at least 450 kilograms per metre. The Super Spacer® also scores highly in terms of the durability of the insulating glass units. Due to the elasticity of the material the probability that the edge seal will be affected by thermal stress drops to almost zero. In addition the tension of the glass units on the edge sealant is minimised. Super Spacer® enhance product quality and aesthetics Transparent aesthetics are the hallmark of the Gersthofen-based glass refiners. This also includes the all-round stepped glass units for transparent facades that can be realised by steps of up to 700 millimetres at the bottom edge. The discreet appearance of the Super Spacer® represents another advantage for developers and architects. The setting by means of an applicator head that is accurate down to the last millimetre guarantees the parallel application of the spacers and flawless edge composition even at print edges. Thus the new insulating glass line does not just set the standard in terms of its production efficiency, but above all in terms of its reproducible quality and aesthetics. The solution for curved glass facades The high art in facade construction and glass processing are curved glass elements such as are installed in the sensational concave and convex facades made of natural stone and glass of the Düsseldorf Kö-Bogen (“King’s Bow”). This facade structure that is unique in Europe for the two-building complex was, similarly to Kompassen, effectively a black box project for glass processors and facade designers - in this case Döring Glas from Berlin and the Lindner Group in Arnstorf. Following a complex development process with numerous test runs, the technical solution was finally created, that satisfied all the parties, both in architectural and also building physics terms. Christoph Rubel explains what importance the spacers have in a project of this magnitude – a facade surface of nearly 15,000 m2, of which approximately 2,200 m2 are curved and bent glass elements that are custommade and envelop the building: “The glass elements were bonded both internally and externally in the Kö-Bogen, whereby the outer bonding acts as a mechanical safeguard. Glued glass connections require a UV-stable, gas-tight silicone sealer. Using our premium product Super Spacer® TriSealTM Premium Plus we have repeatedly passed the compliance tests according to EN1279 with standard insulating glass silicones. Therefore, we also meet the most stringent criteria for the processing in structural insulating glass elements. 2,200 m2 of insulated glass units in different radii and panel widths of 2.70 metres and heights of up to 5.60 metres were manufactured for Düsseldorf. This can only be achieved as a glass processor with a flexible spacer that adjusts to any conceivable glass form and can be precisely positioned down to the last millimetre to ensure the parallelism of the glass panes.

intelligent glass solutions

Executive Boardroom Commentary

The advantages of the Super Spacer® • • • • • • • • • • •

intelligent glass solutions

Low thermal conductivity More durable edge seal Moisture permeable, flexible foam matrix Higher portion of drying agents absorbs moisture Pleasing aesthetics High quality silicon for better resistance to ozone, UV lights and oxidation Very good values for gas leakage rates in accordance with EN 1279-3 Optimum value for energy efficiency (Ψ values to 0.028*) Passive House certificate for Artic Climate More comfort and well-being near the windows Outstanding resistance to condensation and forming, as well as colour stability

• Extreme durability for long-lasting performance • Higher levels of productivity thanks to simple processability (only three process steps) • North America ASTM E2188/ E2189/ E2190 • Europe EN 1279 • Canada CGSB 12.8 • CEKAL - certified for France • P1 Industry standard USA * Super Spacer® Premium made from structural foam includes three panes of insulating glass with hot melt sealant; Source: Bundesverband Flachglas e.V. (German Flat Glass Association)

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IGS in conversation with Guus Boekhoudt

Straight

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IGS in conversation with Guus Boekhoudt

Talking Guus Boekhoudt The IGS Interview

1) Youâ&#x20AC;&#x2122;ve been at the helm of Guardian Glass Europe over a year and a half now, is the job as enjoyable as you thought or is it more challenging? I would say both, and part of the enjoyment is the fact that there are so many interesting challenges. We are experiencing strong glass demand which creates challenges to maintain the level of service our customers have come to expect. Furthermore, we are in the midst of a transformation to a more customer-focused business. Nothing is more enjoyable than working with an organization that is performing well and moving forward in development. 2) What were your key objectives for the group when you decided to accept the position, and are you on track to meet those objectives? When I arrived, it was important to change the mindset of Guardian Glass in Europe from a manufacturing-driven glass producer to a more customer-focused, industry-leading business. Change of this magnitude takes time. I am naturally impatient, but I think we are making good progress. I base my assessment on what the customers are telling me

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through direct conversations, and on our customer loyalty assessments. While we are on the right track, we have much room for improvement when we consider how we service and collaborate with customers to create value for both parties. 3) The glass industry talks openly about innovation, or the lack thereof, what or who is driving this innovation? Your take on this subject is an interesting one, please share with our readers just what innovation means to you? Too often we limit our thinking about innovation to just product performance. We need to expand our definition beyond the performance of our products to include novel ways of reducing waste in our processes, improving service to our customers, better managing inventory through the value chain, optimizing product portfolios, better utilization of existing assets and expanding our knowledge of glass applications. If you open the definition to include the entire glass value chain, there are so many opportunities. Can we do better? Absolutely. What we need is for the customer to help drive innovation, not just the glass manufacturer. We need to listen, understand and anticipate their needs.

IGS in conversation with Guus Boekhoudt

Photo: Guardian Industries Corp.

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IGS in conversation with Guus Boekhoudt

La Cité du Vin, France Photo © XTU

4) Architects say when a salesman shows them 2 glasses and claims they are both “neutral”, tests reveal discrepancies in the neutrality. Then if they compare a third one, also claiming to be neutral, quite often it’s even worse. So is it possible for architects to get unequivocal scientific proof, indisputable facts about the glass they are considering to use in their buildings? Talking about “performance” of a product is easy. It is based on test data, measures and commonly accepted standards. We have key indicators for this, such as light transmission, solar factor, etc, that are undisputed and the value of these parameters are understood. As soon as we talk about aesthetic properties of the glass, we enter into a very subjective area where emotion and perception have the highest influence. On top of this, the human eye is not equally sensitive amongst human beings to “color”, and each of us have our own interpretation and vision of what is appealing. Despite the fact that we can “measure” color, the emotional interpretation of those numbers will vary from person to person. The variation of this interpretation is much more diffused when we talk about neutral color and consequently “neutral” looking glass follows the same trend.

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So, to answer your question, we can measure color but as long as technology will not be able to model human emotion and perception, we will not have a 100% accurate tool to assess the aesthetic appearance of glass. 5) We need to secure the long term future of architectural glass. Imagine a huge energy price rise that forces environmental concerns to be the main priority, and people point at glass buildings like smokers in a restaurant. Companies then decide not to have glass in their new headquarters because it’s politically incorrect and scorned upon. The glass industry would be technically knocked out of what Scott Thomsen called “The battle for the Wall”. How can we prevent this scenario from happening? A battle for the wall cannot be based solely on one attribute. Your scenario only focuses on insulation or U-value properties of glass. However, energy efficiency of homes and buildings is a highly complex problem. What we need is to tell the story correctly: glass is not the problem, but rather a key component of the solution! As an industry we simply need to be more effective in telling the whole story.

IGS in conversation with Guus Boekhoudt

Photo: Anže Čokl, anzecokl.com

Advancement in coating performance means that glass facades are more efficient than they have ever been. Today we build larger glass facades than ever before, mainly due to improved coatings and energy balance allowing passive heat from the sun to help warm buildings freely whilst controlling the transfer of energy to allow them to effectively save energy. Glass allows natural light into a building, reducing the need for powerconsuming, artificial light. Glass enables passive solar heat gain that is very beneficial in cold months. High performance glass combined with double and triple glazing can provide both solar control and insulation. We also need natural daylight. It helps office workers’ eyes refocus comfortably while they work, it provides a sense of well-being and helps us embrace our environment. We came from caves; why would we want to move back? Glass may be energy intensive to produce, but its benefits and the coating we apply make it far more energy neutral. I believe in the future glass will be an integral part of renewable energy solutions. The real challenge is how to generate more functionality from walls and roof space, either by generating energy or by making roofs publicly accessible and/or used for leisure, “urban farming”, etc.

6) Returning to innovation, the greatest show on earth just took place. Tell us what the visitors to glasstec were dazzled by on the Guardian stand? The majority of the 40,000 visitors that attended glasstec 2016 could not have failed to notice the presence of Guardian Glass and our impressive, 2-storey stand showcasing some of the latest innovations and applications in float and fabricated glass. The Guardian exhibit provided a source of inspiration and I would like to encourage everyone to visit Guardian’s http://ggstori.es website for an overview of what we exhibited. Under the “Inspirations in Glass” theme, we focused on the performance and aesthetic appeal of our glass in application. A few of the products and technologies we showcased include: • A 6-metre-high, curved glass facade showcasing our latest advances in glass coating technology for varying levels of reflectivity, thermal insulation and light transmission • Innovative and inspirational design concepts for colored glass applications and interactive displays • The no-glass effect of Guardian Clarity™ anti-reflective glass in a range of applications, and • ClimaGuard® Blue LM 1.1, a self-cleaning glass for conservatories. We also announced the winners of the Guardian Glass Student Design Challenge, a competition focused on interior applications for our Clarity™

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IGS in conversation with Guus Boekhoudt

Photo: Anže Čokl, anzecokl.com

anti-reflective glass. The first prize was awarded to Angelo Blythe and Anastasia Tasoula Kontzes for their “Guardian Clarity™ Sightseeing Boat” design concept. The second prize was taken home by Simon Seidl for his “Glass Partition” proposal. Emanuel Etzersdorfer and Felix Stadie won the third prize with their “tme. Glass clock” project.

building owners. We continue to reduce internal and external reflectivity to improve the viewing experience, particularly at night. Coatings have become increasingly color neutral.

7) In your expert opinion is the glass coatings industry exciting enough, is it doing sufficient to improve the performance of facades - basically, is there a disruptive coating technology on the horizon?

These improvements combine to deliver better performance today. Whether or not there is a disruptive technology on the horizon, I cannot say. What I will say is that we must expand our view of coating technology. With triple glazing, we now have six glass surfaces to work with in the IGU. How can we use each surface to potentially improve the façade performance?

I think magnetron sputter coating continues to be an exciting technology. We continue to stretch the limits of selectivity, the ratio of light transmission to solar factor, responding to needs from architects and

Additionally, we must not forget that glass is only a component in a complex façade system. Future coating technologies must integrate with or enable the next generation of façade, including dynamic glazing.

“

Energy efﬁciency of homes and buildings is a highly complex problem. What we need is to tell the story correctly: glass is not the problem, but rather a key component of the solution!

” intelligent glass solutions

IGS in conversation with Guus Boekhoudt

Photo: Guardian Industries Corp.

8) Guardian has spearheaded technology for a number of years, you have a plethora of world leading products but competition is fierce. Is Guardian still the heavyweight champion of the world when it comes to glass coatings? Regardless of how we describe our position in glass technology, we want to continuously drive product innovation that creates real value for our customers. The only “title” we care about is whether we are their first choice. Without continuous innovation we will lose that first choice position. 9) What makes Guardian different from other glass manufacturers, what is the company’s unique selling point? I think what sets Guardian apart from the competition today is our culture and our intense focus on the customer. We do not produce Insulated Glass Units (IGUs) in Europe, therefore we must compete based upon the value we create for our customers, from the processor to the building owner. We cannot rely on internal demand created by downstream fabrication businesses of our own. We must provide great service, outstanding quality and value-added products because all of our customers have choices. Competition keeps us focused on winning that brand choice. 10) Gorilla glass is so thin it’s difficult to find a use for it other than in our mobile phones, vacuum insulated glass and electrochromic glass have been around for some time now, but they seem to be driving with the handbrake on - people thought these were earth shattering developments at the time so what’s the problem here? I can’t comment on another company’s business strategy or decisions. What I can say is that conceptually, products like that try to meet the fundamental needs of the consumer. Thinner glass would help reduce the façade weight, provided it has the necessary mechanical strength. Vacuum Insulated Glass (VIG) can dramatically improve the insulation properties of windows and façades. Dynamic glazing answers the occupants’ desire to have a façade that actively manages the balance between light, glare and solar energy. Many companies seem to have real interest in all these technologies. However, it comes down to value. Is the incremental cost of the new technologies creating equal or greater incremental value versus today’s available alternatives? Is the supply chain capable of delivering this value? Today’s commercially available solutions are at a stage where they 1) don’t meet all of the requirements (such as safety), 2) are too expensive for the performance they bring, or 3) are too complex for the players in the supply chain to effectively implement them. Eventually, solutions will emerge that create real value and we expect to be part of this evolution.

11) Owners, investors and architects still cry for large expansive pieces of glass, the eternal call for natural daylight to connect inside to the outside etc. is there an opening here perhaps for large sized chemically tempered glass? Increasing the amount of natural light in buildings, houses and cars is one of the fundamental drivers in design and architecture. As a consequence, architects and designers want to get rid of all structural elements. Frames should be thinner or disappear for windows, a glass façade should be frameless and fixed on the building itself, glass should cover two floors instead of one… all these applications currently require thick glass, either tempered, laminated or both, for safety reasons.

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IGS in conversation with Guus Boekhoudt

La Cité du Vin, France Photo: © XTU Patrick Tourneboeuf

If the glass industry found the technology to produce the base glass so that it could match this safety requirement and keep all other properties without having to add another costly step (tempering, lamination, etc), this would be the real breakthrough. 12) It’s in the incubation stage, but talk of glass companies leasing as opposed to selling glass has become an executive boardroom discussion. What is your opinion on leasing glass facades? Clearly there are significant inefficiencies in the glass value chain between the manufacturer and the building owner. I see opportunities to increase efficiency and create value for the building owner. Current façade design is difficult to change or update with the latest design trends or the latest glass technology. Therefore, it becomes a fixed technology for much of the life of the building.

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The concept of managing the façade through its entire lifecycle has merit and there are systems used in buildings today that are managed in a similar way. I think it is certainly a concept worth exploring. Ultimately, as with most new ideas, the challenge will be to execute on the details while creating real value for the customer, the building owner. 13) Does glass have a bright future? Where will the industry be 50 years from now? No question glass has a bright future. Sure we will go through natural economic cycles, but glass is fundamental to so many human needs. I don’t think the desire for a comfortable living space with natural light will be any different 50 years from now. The need to protect or preserve something while still being able to view the object will not change. I think the biggest changes for glass in the next 50 years will be in how glass is used and how it enables interaction with our surroundings.

Amazing projects in glass

THE OPUS AT BUISINESS BAY, DUBAI. By Agnes Koltay and Guillermo Fernandez, Koltay Facades, Dubai.

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Amazing projects in glass

ituated in the centre of Dubai (UAE), in the Business Bay area, The Opus is a 20 story building which is currently under construction and is set to soon become one of the icons of the city. It is a mixed used hotel and office building consisting of two concrete towers connected by a steel bridge on top and a large steel supported atrium roof at the base, entirely cladded with glazed curtain walling. The external facades are built with transparent glazing with a mirror pattern, in contrast with the freeform inner “void” area which was envisaged having dark blue glazing. The building was designed by Zaha Hadid Architects for Omniyat properties. The main contractor is Brookfield Multiplex, the cladding contractor is Alu Nasa Aluminium Industry and the façade consultant is Koltay Façades. Site works commenced in 2008 but then paused until late 2012, with the first cladding panels being installed on the building in December 2014, after concluding a thorough search for pioneering solutions in glass custom patterning and custom-shape bending.

The internal void façade: The void façade geometry is a smooth compound of freeform curved surfaces which was panelised into quadrilateral modules responding to the projections of a regular network of lines originating from slab levels and from the structural gridlines. This modulation resulted in unique shaped panels with an average glass size of 1500 x 1950mm, with 1900mm being the widest and 2510mm being the longest dimension. Soon into the project a comprehensive panelization study took place using Rhino and Grasshopper software to analyse individual units, by checking offsets of the fourth corner in relation to the other three corners of a panel that define a reference plane. Values of around 80-90 mm were common; on the whole project they are ranging up to 150mm. This analysis was essential for assessing the different methods of producing curved glass. Available glass forming methods: Though some areas consist of flat panels or single curved panels, the majority of the void façade is comprised of complex double curvature panels.

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Amazing projects in glass

Single curved glass, cylindrical and conical, is relatively easy to produce. This process takes only a few minutes and is done by special furnaces that have been available for years and are capable of curving and tempering at the same time. On the other hand, double curved glass is much more complex to produce. Flat glass is placed over custom-fabricated moulds (adaptive moulds are still not a working reality) and heated up to approximately 700Â°C. As glass slowly softens, gravity causes it to sag and take the shape of the mould supporting it. This method is slow, and sagging into the mould is not accurately controllable so it requires a good amount of trial and error to succeed. It takes 6-16 hours to produce a panel which will not be tempered. Considering that dark glass with a high solar energy absorption would be used, thermal stress was a real risk in Dubai climate and glass needed to be tempered. Chemical tempering was available, but it is a long and pricy process, with difficulties of getting long term warranties in a high sand abrasion environment. For these reasons, the goal was to minimize the amount of hot bent panels, and in consequence we reached out to cold bending tempered flat glazing. Cold bending is a cost effective way to shape glass. It can be done in different ways: by bending glass only (shape forming with laminate), or by bending the whole unit (glass and frame together). For the later one, a flat unitized curtain wall unit is produced and then one corner is forced into an out of plane position during construction using a special bracket. To our advantage, we at Koltay Facades had already carried out a series of physical tests for previous projects with the help of Exova testing facility in Dubai. Panels were tested with a hydraulic jack attached to the top corner and by incorporating transducers for measuring the resulting twist after incrementally increasing the offset values. By monitoring and observing the behaviour of cold bent panels, short term and long term, these experiments helped to quantify the bending limits in relation to panel sizes and proved that the cold bent units can and should be designed with the sides straight, essentially folding along the diagonal, rather that curving the edges.

While there was an effort in establishing the limit value for cold bending â&#x20AC;&#x201C; with 80 to 100mm considered at different stages â&#x20AC;&#x201C; after carefully taking into account the framing system, it was decided not to use cold bending in the way described above. Firstly, the interfaces between cold bent panels with effectively straight frames and hot bent units with curved frames would require transfer panels, further complicating the system. Also, to further complicate things, each floor height unit has two pieces of glass with a mid-transom. Additionally, the skylight system would also need a different approach than simply trying to pull one corner out of plane.

Instead of this, the solution that was finally adopted for certain panels with a low degree of curvature and relatively small offsets was to produce flat glass and curved frames and to cold bend the glass while bonding it with structural silicone to the curved frames. Void area glass: To summarize the above explained glass forming selection process, there is some cold bent glass on the project, however the majority is in fact hot bent glazing. This double curved glass presented a high risk of thermal breakages: it has very high solar energy absorption due to its dark colour, however it

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Amazing projects in glass

cannot be tempered in a conventional way or chemically tempered for this application. An approach was taken to determine the amount of solar heat load each piece of glass would be exposed to, and the maximum absorption that can occur without thermal breakage. In this process a new challenge was discovered. The shape of the void is such, that one portion of the faรงade forms a concave lens that focuses reflected solar waves to the other face. A study, using Ecotect, Rhino and Grasshopper, was carried out to determine this focusing effect over the year and to see the critical case caused by the focalized reflected waves which obviously responds to hourly and annual sun path variations. The study concluded that the external reflectivity of the glass was to be kept below 15% in order to avoid problems from these projected hot spots. The initial glass build-up type considered was a dark blue tinted product, Privablue, with low-e coat. This was quickly disregarded for its high solar energy absorbance and risk of thermal breakage. A coloured PVB laminate was then proposed. However, this option also had problems, as

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the void glass is installed in vertical, inclined, skylight and soffit locations, necessitating the laminated layer to be placed differently on the outer or inner lites of the double glazed unit. This resulted in a significant visible colour difference due to the different placing of the blue laminate in front of or behind the low-e coat which heavily affects the performance and

appearance. Another problem with this buildup was the high external reflectivity, which magnified the earlier explained focalizing effect. The design then reverted to a body tinted option, but this time with two layers of lighter blue glazing, a product from Taiwan Glass which distributed the solar heat more effectively. Additionally, the low-e coating was moved

Amazing projects in glass

to the inner lite, which is not ideal for a hot climate, but was a necessity in order to reduce the absorption on the outer pane. In addition, silicone foam warm edge spacers were used in order to avoid temperature shock at the edges. To verify this solution, the final build-up was independently tested for thermal breakage by heating one half of the panel with infrared lamps while the other half was cooled with water mist, thus resembling a partial shading scenario. The external glass. The external glass was designed by the architects with a changing diameter dot pattern, applied in stripes for an overall pulsating effect. There was a big concern in the number of templates needed for creating this motive. Following a rationalization of the pattern the number of the templates was reduced to 12 only, used both in upright and upside-down positions. In the future, with the spread of digital technologies, this will not be a concern anymore, however at the time it resulted in a significant cost saving. This pattern was intended to be a high reflectivity mirror appearing coating, and finding a product that fitted the budget, matched the aesthetic requirements and allowed low-e coating on top was a long process that involved a number of glass manufacturers. The final product was obtained through a similar process to ceramic fritting. A mirror ink was applied on the glass through silk screening and dried in a furnace prior to deposition of the low-e coat. The glass was then assembled to IGUs with the patterned coated surface being in position 2, which gives the best performance in hot climates. The framing systems. The external facades and the vertical and inclined areas of the void facades are built with a unitized curtain wall system. To allow for easier bending of the curved elements, a female-female system was selected due to its more compact â&#x20AC;&#x153;box likeâ&#x20AC;? members. There were several unique challenges, such as draining certain locations where the surface inclination would not allow so, or substituting the load transferring swords, which would make installation difficult if placed in curved members.

Manufacture and assembly. Different components of the facade are manufactured and supplied from various countries around the globe. Mirror glass and curved glass was sourced from China, bent aluminium from Denmark, bent steel from The Netherlands, with assembly of panels taking place in Dubai. Ensuring these custom shaped parts fit together was a great challenge, and in response to this the contractor developed a very detailed 3D model in order to obtain precise material dimensions. A coordinated approach for shape control and consistent tagging and labelling took also place from the same central 3D model.

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Amazing projects in glass

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Amazing projects in glass

The skylight and soffit systems are back drained cassette systems. It was important that the glazed panels have a carrier frame, for better shape control, protection of the edges during handling, and improved overall system performance. A sophisticated lighting system was integrated into the façade as well. The night time vision for the project is to have a matrix of lights that are invisible during daytime but allow the void to glow and pulsate at night. Each light will have its own IP address allowing to program colour and intensity changes. The lights are placed on a regular grid and hidden in the joint, without blocking system movements. All materials were checked several times, both at origin and in Dubai. QA/QC checks for shape accuracy included measurement with stretched piano wire, digital 3D scan, or CNCcut foam counter moulds. Similarly, the project has freeform glass fibre bulkheads integrated into the panels. They are also 3D curved and have been laser scanned for shape accuracy. Conclusion. Technology is constantly progressing and what we have been witnessing in the past years of The Opus development, is how the unique, the customized, the “each piece different” structures can be designed and manufactured using computer technology and in a way that the production itself is mass production, but the outcome is each unique and different. There is no question that it is easier to build The Opus today than what it was a few years ago, and will probably be even easier in a few more years’ time, when critical elements may be just 3D printed in situ. However, we do need projects like this, to push the limits and induce progress. We see unique pieces produced and handled as repetitive pieces. We are witnessing the “unique” transforming into “usual”.

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Amazing projects in glass

intelligent glass solutions

Amazing projects in glass

The Zig Zag Building, London Faรงades acting as intermediate spaces Sun protection glazing with stone-look printed PVB interlayer

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Amazing projects in glass

Photo: Simon Kennedy

The Zig Zag Building is part of a development area in London’s Victoria Street designed by Lynch Architects and developer Land Securities bringing civic qualities to this area and creating a lively town center. The name Zig Zag Building refers to the irregular shape of the building with its multiple recesses. Vertical fins are echoing the verticals of Westminister Cathedral and City Hall. These façades are acting as intermediate spaces with openable windows, balconies, roof terraces and welcoming areas on the ground floor. Horizontal as well as vertical sheet metal fins give the façade is specific structure. The vertical fins support a curtain-type sun protection with stone print PVB interlayer. The residential and office building with its recesses and terrasses is harmoniously merging with the surrounding stone buildings. Each façade element is unique – this is also due to the varying dimensions between axes of the façade units which have been fabriquated by the German curtain wall manufacturer Gartner. Façades speaking to the city The 80 m long and 30 m wide development in Victoria Street, near Buckingham Palace, consists of a residential building and an office building. To the East, the building reaches it highest point at 52 metres which is slightly underneath the neighbouring Westminster City Hall.

Klaus Lother, Josef Gartner GmbH

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The 13-storey building is a mixed use development with offices above two floors of retail units. Architect Patrick Lynch wanted to realize an urban office design. „It’s the façade that speaks to the city,“ says Lynch. So the façade should act as a threshold between the world of its occupants and the city beyond. Users should be able to occupy, relate to and interact with the public/surroundings by opening windows or stepping on to terraces. Therefore, the façades should act as intermediate spaces rather than opaque or reflective boundary planes. Lynch is inspired by Renaissance Florence: „They have a base and a top, and there´s a delicious pleasure in walking past these buildings because their lobbies are like urban rooms.“ At low level, the Zig Zag Building has active retail frontages, stepped in section.

Amazing projects in glass

intelligent glass solutions

Amazing projects in glass

Abundance of natural light and openable windows The building offers 188,700 sq. ft. commercial office space with private terraces on 7 floors and also a total of 187 cycle parking. The building is characterized by flexible floor plates, an abundance of natural light, and enviable sustainability credentials. It expands the public space by throughfares, gardens, restaurants and retail. Most of the shops, office and residential areas were let or occupied in 2015, including a restaurant of the celebrity chef and restaurateur Jamie Oliver. In November 2015, Deutsche Bank Asset Management and Private Wealth Management relocated to Zig Zag Building. Mechanical ventilation is not needed thanks to a façade with careful sun-shading and openable windows together with cooled ceilings. Furthermore, the building is designed to last more than a century and has been awarded the prestigious BREEAM „Excellent“ certificate. The building is also winner of the „Commercial Development“ of the Year at the 2016 PROPS awards in May 2016. Low-iron glazing with printed PVB interlayer and onyx pattern The architectural design is dominated by curtain-type horizontal and vertical metal sheet fins which give structure to the building and are aligned to an internal grid of 1,5 m distance. As the building depth and the distances between the building axes are diminishing from the ground floor to the upper floors, the distance to the front edge diminishes as well making the building look narrower as it rises.

Photo: Sandra Martin, Lynch Architect

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At the upper part of the vertical fin interspace, there are glass panes of 1,100 mm height each, protecting the tenants from direct solar radiation. Especially during hours of high sun elevation at the south side of the building, the fins provide good shading to the rooms. Low-iron glasses which allow for good colour reproduction, have been provided with a printed PVB interlayer resembling onyx stones. A total of 23 different onyx patterns have been fabricated by use of special printing technology and installed into their individual position at the building. The laminated safety glass panes with printed interlayer were thus given their unique aspect and create irregular patterns. As compared to the printed glazing, glasses with printed interlayer also allow for more complex and multi-coloured designs.

Amazing projects in glass

Unique façades with different axial dimensions Most of the elements of the façade with its total volume of 11.500 m2 are 3,85 m high and weigh approx. 800 kg. The planning grid is approx 3 m. Due to the irregular floor plan of the building and the different sizes of the fins there are numerous types of different axial dimensions. Into each façade unit, Gartner has installed individually operable window leaves with Juliet balconies. Die pivot windows can be opened mechanically in positions from 15 up to 90 degrees. Here, tenants can choose whether they prefer to only open the upper part or the full height of the window down to the floor. Mullion-transom façades in three different designs Other areas were mostly closed by 1,200 sqm large mullion-transom façades in three different designs. Recesses, ceilings, terraces or soffits are continuously subdividing these areas. The stainless steel mullions of the 8 m high entrance façade area are positioned at the outside instead of the inside, this area has, therefore, been glazed on the inside. The ground and first floor on the north side were clad with louvres on the steel tubes of a mullion-transom façade. The major part of the façade is bronze anodised. On the ground and first floor, the façades are clad vertically with brushed stainless steel panels, and with mirror finish stainless steel panels on the soffits. Double insulating glass with laminated safety glass Office areas are glazed with double insulating glass with laminated safety gass VSG, inside as well as outside (outside with heat strengthened TVG) with a solar control coating Sunguard HS SN 70/37 HT. The shops in the lower two floors are also provided with double glazing, with laminated safety glass VSG (outside with heat strengthened TVG) inside as well as outside, and with solar control coating Sunguard HS SN 62/34. In addition to the façades, Gartner supplied a canopy, door systems with storey-high sliding doors, revolving doors and pivot doors, balustrades in stainless steel, aluminium and glass, the sheet cladding of the façade, louvres for the roof area, and the cladding of the roof structures with louvres and glass. Photo: Simon Kennedy

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Amazing projects in glass

Photo: Sandra Martin, Lynch Architect

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Roche Bau 1, Basel (Switzerland)

Closed Cavity Façade

Engineering Visions in Glass and Aluminium Josef Gartner GmbH | 89423 Gundelﬁngen | Germany +49 9073 84-0 | www.josef-gartner.de | info@josef-gartner.de

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Amazing projects in glass

Transparency through geometry â&#x20AC;&#x201C; a case study Lisa Rammig, Eckersley Oâ&#x20AC;&#x2122;Callaghan

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Amazing projects in glass

lass has always fascinated the creators of buildings due its inherent defining property – transparency. From mystical spaces in gothic cathedrals, to today’s transparent building envelopes; glass continues to be a major design component in architecture.

In the past century, glass has increasingly been used as a structural component. However, its inherent brittleness still requires opaque metal connections to transfer loads, which commonly are stainless steel or titanium. These connections define contemporary glass architecture – firstly, because they are immediately apparent in a transparent structure and, secondly, as they are part of the engineering design language. However, designers and architects are still aiming to increase the transparency of building envelopes and structures, hence there is a strong demand to reduce the visibility of structural connections in glass. In particular, glass staircases have gained popularity in recent years, forming transparent structural features within buildings. Due to the loads they have to carry, coupled with safety regulations, these structures traditionally consist of many layers of glass, laminated into thick packages and then connected with opaque metal fittings. Structural adhesives have become increasingly common in facade applications, where loads are transferred from glass-to-glass, or from glass to supporting structure, through silicone. Transparent structural adhesives, however, have been mainly explored on an experimental basis and are not often found in building applications. In parallel to the development of structural glass design, architects have developed more and more organically-shaped buildings, leading to progressively demanding requirements for the size and shape of the materials used for cladding.

This is also extended to the glass, a material that is traditionally produced as a flat element. Due to its inherent brittleness, glass must be heated when curving to tight radii. Several curving technologies allow for different sizes and curvatures to be achieved. Automated curving ovens, shape and toughen the glass at the same time. The glass is placed on adaptable rollers inside a kiln that can form a radius down to approximately 1000mm. While the kiln heats up and the glass softens, the rollers bend it into shape. Then the glass is quenched, similar to a standard toughening process to create a stress differential through the thickness of the material, leading to higher allowable stress and therefore greater strength of glass. Due to the limitations of this process, very tight radii and double curvatures cannot be easily achieved. An alternative is a gravity bending process where flat glass sheet is placed over a mould and heated up in a kiln to slump the softening glass over the adopted shape. Rather than rapidly cooling to achieve a pre-stress, the glass requires a slow annealing process to release any stress that has been induced in the process. This bending process not only shapes the glass, but also increases its stiffness by adding structural depth. Design process: The installation described here is intended to showcase the technical possibilities of curving and connecting glass as well as expressing the beauty and transparency of the material at its best. Eckersley O’Callaghan collaborated with fabricators Cricursa to develop the design of a glass slide, which was featured at the Glass Technology Live exhibition at GlassTec 2016. Curving the flat sheets to a very tight radius (450mm) embeds inherently stiff, allowing the glass to span 9 metres in this triangulated configuration with only 2 layers of 10mm glass.

Typically glass structures consist of many layers of glass, connected with opaque fittings that transfer the load.

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Amazing projects in glass

Curved glass prior to installation

In comparison, a flat glass would require approximately 10 layers of 10mm glass to achieve a similar span. Adding this amount of thickness to the glass significantly reduces transparency due to the increased absorption. Reducing the thickness of the glass, by introducing a curvature, increases the light transmission by 20% compared to the thicker flat build-up. Visual light transmittance however, is not the only factor playing a role in the appearance of a transparent object. The colour plays a very important role in the perception of transparency. The smaller the perceivable tint in a glass, the more transparent the glass appears. Even on a glass with a reduced iron content, as used in this installation, a tint exists which becomes more visible the more layers of glass are stacked together. The concept was to develop a structure expressed as a very simple shape while being functional and pure in its design language, using as few visible connections as possible. It comprises two half cylinders, leaning against each other in an asymmetric manner form the slide. The only visible connection of the two pieces is formed by a 12mm silicone joint at the top. Structural concept The installation works as a triangulated, pinned structure, which is held at the bottom in stainless steel shoes connected to a continuous steel frame. To achieve a flush sliding surface, the stainless steel shoes are located on the underside of the glass only. Dead load is supported through the

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rebate at the bottom of the shoe, which is connected to the glass with structural silicone. The treads forming the slideâ&#x20AC;&#x2122;s ladder are solid borosilicate rods which are machined to fit the shape of the cylinder and fixed with a transparent silicone adhesive (TSSA). This material is much stronger than traditional structural silicone and can therefore be used in very thin layers. However, pressure and temperature are required to achieve a sufficiently strong bond which means the connections must be cured in an autoclave similar to common polymer interlayers. Whilst TSSA has previously been tested on glass-metal connections, glass-glass connections have not been formed. Due to the complexity of exactly fitting a glass rod into a specific location on a cylindrical glass, which has fabrication tolerances up to 7mm, several design options were considered. Metal connections could have been locally laminated to the cylinder, and allowing the glass rods to be â&#x20AC;&#x2DC;hooked onâ&#x20AC;&#x2122;. This option was considered as laminating the glass rods requires very precise analysis of the existing glass geometry and significant machining and adjustment of every single glass rod to achieve a close fit. The metal fittings would be more forgiving, as tolerance could be taken in the connection between metal fitting and glass rod.

Amazing projects in glass

Design and connection development Another advantage of the metal connection was the additional movement tolerance which could be accommodated at the connection, and so reducing the stress concentrations in the glass bars. However, this approach of using metal fittings would have significantly compromised the desire to maximise transparency. An additional option was considered to reduce the complexity of the TSSA connections which included notching the inner layer of glass to create transparent supports for the treads whilst offering movement as per the previous option. A transparent silicone ring was proposed to provide friction between tread and glass support. Although this option provided significantly simpler support conditions, the complexity of the bending process would have increased, as the glass would have to be notched prior to the bending process. The geometry of the support would have been dependant on the precision of the curving process. Although this option enables transparent connections, it would have compromised the simplicity of the design by adding complex shapes, exposing glass edges towards the inside of the slide, leading to increased reflection and refraction and reducing the perceived transparency of the construction. Fabrication: The two main parts of the slide consist of two sheets of 10mm low iron glass, each laminated with 1.52mm of SGP. To achieve the very tight radius of 450mm, the glass is bent in a gravity process over a steel mould. To achieve a good fit of both glass layers in the subsequent lamination process, both panels are bent together at a temperature of approximately 600Â°C. In an annealing cycle, in which the glass is cooled down from bending temperature to room temperature very slowly, the stress induced into the panels during the bending is released. After bending, the two glass panels are separated and a ionoplast interlayer is placed in between. The bond is achieved by temperature and pressure for which the glass is placed in an autoclave. After the lamination process, the top glass edge was polished to assure that the two glass edges to be

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Amazing projects in glass

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Amazing projects in glass

siliconed together at the top were exactly perpendicular. Due to schedule limitations, this was performed manually. However, it would have been possible to replace the manual polishing process with a 5 axis CNC process which would achieve an accurate chamfer. The treads had to be laminated in a separate step to better control quality during the lamination process and achieve maximum accuracy. Summary The goal of this case study was to design a glass structure using a minimum material and connections to showcase the beauty of transparency that glass offers. Connections are reduced to a minimum and do not penetrate the glass surface making them less apparent. The continuous reflectivity of the surface is maintained where the shoes sit behind the glass. The 12mm silicone joint connecting both pieces of glass at the top has a reduced visual impact due to the simplicity and linearity of the connection as well as lightly defining the geometric junction between the two tubes.

On the ladder, the high number of connections are kept transparent, making it difficult to distinguish between the tube and the glass rods; they become one transparent component. Most importantly, however, a design has been developed that reduces the amount of material used and increases the transparency of the structure by making use of the geometrical stiffness gained by bending the glass into a tight curve. The clarity achieved with this approach is significantly greater than using flat glass to span without additional support. This leads to the conclusion that the use of geometrical stiffness might be a useful approach for the design of glass structures, either by introducing stiffness through small amounts of cold bending, or through the work with thin and ultra-thin glass which requires a design approach that limits the flexibility of the material. The significantly increased strength of these high strength ultra thin glasses would allow curvatures to be introduced even through cold bending and might lead to even greater transparency.

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We’re not done yet, as always, there’s still PLENTY MORE TO COME! On page 64, Jutta Albus & Johannes Pellkofer of Stuttgart University remind us of a few highlights from the inimitable glasstec 2016 that took place in Duesseldorf back in September 50 years of proven performance with silicone structural glazing, Dr.Andreas Wolf & Dipl.-Ing Christoph Recknagel provide compelling evidence for this technology on page 82, whilst on page 98 we enter the technical world of Larry Carberry who takes over IGS for 18 pages and reveals results for a comparison of the thermal transmittance of curtain wall spandrel areas. You’ll most likely get your architectural glass engineering degree after reading this paper. This is IGS after all, the glass industry publication known around the world for having the most super intelligent, the most good looking and the sexiest readers of any magazine that exists under the sun! IGS, there is nothing more, nothing less... Nothing Else!

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Amazing projects in glass

Remembering Zaha Al Alﬁa Holding announces projects by Zaha Hadid Architects for Lusail City Doha, Qatar

Commissioned by H.H. Sheikh Mohammed Bin Khalifa Al Thani in 2013 as part of Lusail City’s masterplan to create a sustainable, integrated community, Zaha Hadid designed two projects for Al Alfia Holding. Zaha Hadid Architects (ZHA) will now develop the first project, a 70,000 sq m hotel with residential apartments to complete in 2020, in Lusail City’s Marina District. The second of Hadid’s designs commissioned by Al Alfia Holding will be built within the on-going plan for future development of the city. Designed with innovative solutions as an environmentally sustainable community of 450,000 residents and visitors, Lusail City incorporates a 38km light rail system to transport them throughout the city with direct connection to the wider Doha Metro network. Integrating its management and conservation of water within an urban landscape, the city’s energy, communications and transportation systems are also planned to automatically adapt to continually changing weather and traffic conditions, making Lusail the most sustainable city in the region. Continuing these ecological considerations, the formal composition of Hadid’s design has been inspired by the structure of the Desert Hyacinth; a flowering plant native to the landscapes and

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Amazing projects in glass

PROJECT TEAM Architect: Zaha Hadid Architects Design: Zaha Hadid and Patrik Schumacher ZHA project director: Charles Walker ZHA project associate: Tariq Khayyat ZHA project architect: Kutbuddin Nadiadi ZHA project team: Gerry Cruz, Drew Merkle, Dennis Brezina, Alia Faisal Zayani, Alessandra Lazzoni, Matthew Le Grice, Mu Ren, Alexandra Fisher, Kwanphil Cho, Joris Pauwels, Jose Pareja Gomez, Katherina Hieger, Konstantinos Psomas, Leo Alves, Mei-Ling Lin, Nicholette Chan, Yifan Zhang CONSULTANTS Structure and Facade Engineers: Arup MEP and Sustainability: Atelier Ten Landscape: Francis Landscape Hotel: GC Hotel Consultancy Food Services: Tricon

coastlines of the Arabian Gulf. The nine-pointed form of the building’s podium surrounds a central core defined by the interwoven fluid geometries of the hyacinth. A filigreed mashrabiya façade envelops the building to reduce solar gain. Fluidity is embedded within the region’s architectural heritage and traditions. Continuous calligraphic and geometric patterns flow from domes to ceilings, ceilings to walls, walls to floors, establishing seamless relationships and blurring distinctions between architectural elements. Zaha Hadid developed this historical understanding of the region’s architecture in a contemporary interpretation evolving from her research into natural systems of organization and structure, as well as applying the possibilities achieved through advancements in design, construction and material technologies to deliver workable solutions for the 21st century.

Hadid’s work sees form and space composed into fluid spatial progressions. Transforming notions of what can be achieved in concrete, steel and glass, Zaha Hadid’s architecture combines her unwavering optimism for the future and belief in the power of invention with concepts of connectivity and fluidity. Working with Arup Engineering and Atelier Ten, global leaders in environmental design and engineering, Zaha Hadid Architects’ vision for the 38-storey project embraces collaboration between disciplines, responding to current and future environmental challenges and providing the most comfortable living spaces for residents, guests, visitors and staff. “With truly inspirational public spaces and atrium, 120 unique residences and 200 hotel rooms of Zaha Hadid’s unmistakable signature, we celebrate her remarkable legacy and continue Lusail City’s commitment to creating the region’s most sustainable, interconnected community,” said H.H. Sheikh Mohammed Bin Khalifa Al Thani, Chairman of Al Alfia Holding.

“We often look at nature’s systems when we work to create environments; at her unrivalled logic and coherence,” Zaha Hadid previously explained.

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#GPD2017

ALL EYES ON GLASS. GLASS PERFORMANCE DAYS 2017 JUNE 28 - 30, 2017. TAMPERE, FINLAND 1

Submit Your Abstract for GPD Finland by

OCTOBER 31, 2016 Second deadline for abstracts January 20, 2017.

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GPD CALLING FOR PAPERS, WORKSHOPS AND EXHIBITORS If you are interested in workshops (27.–28.6.2017) or expo booths, please visit www.gpd.ﬁ

CONFERENCE MAIN TOPICS

Facades

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Glass and Sustainability in Buildings Smart glazing • Facade Engineering • Complex Geometry

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Glass in Architecture Architectural Challenges & Solutions • Glass in Interior design (Decorative & Structural) • Architect Forum •

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For further information please visit www.gpd.fi or contact speaking and sponsor opportunities: jorma.vitkala@gpd.fi, mobile +358 40 553 2042 and brown.onduso@gpd.fi, mobile +358 40 773 9313 GPD Exhibition: Heli Huhtala, gpd2017@meetingsmill.fi, mobile +358 400 737 420

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Amazing projects in glass

Remembering glass technology live 2016 at glasstec in Dusseldorf Dipl.-Ing. Jutta Albus, Dipl.-Ing. Johannes Pellkofer MBA As part of the Glasstec trade fair, glass technology live is a special show presenting high-end glass technologies and facade innovations. Organized by the Institute of Building Construction, Technology and Design Chair 2, under the patronage of Professor Stefan Behling (senior executive partner, Foster + Partners), the show took place from September 20 through 23, in Dusseldorf. For over 22 years, the platform has created a network between architects, designers, and representatives of the glass and façade industry. This year’s special show ‘A Future in Glass’ presented numerous exhibits related to building and construction relevant themes. An area of about 2500 m2 created the framework for the show’s distinctive features such as Smart Glass, Innovative Façades, Heat/Sun Protection Glass, Solar Technology and Glass Design. Focused on glass, this exhibition merges research results, architectural highlights and product developments, thus offering a platform for more than 60 exhibitors to present their deliverables. Along with the latest product technologies and research developments, current glass specific applications were displayed.

Intelligent Glass Technologies Furthermore, the high-tech components enable applications in alternative areas of a building such as multi-functional interior floor or wall elements. The light sources provide an implementation range that can easily be controlled and used as information source by simultaneously generating a multi-diverse appearance. Against this background, a sports flooring by ASB Glass integrated the technology to quickly adapt its surface to a variety of indoor sports. Depending on game configuration, the LEDs allow for easy adjustment of the information lines within seconds. A prototypical development from England exemplified the approach, introducing a 400 m2 glass field that switches between 10 customized configurations in high-speed. The lightemitting diodes, inserted on the inside of the laminated glazing, support an identification of active lines for the respective sport. Etching on the glass surface reduces glare and reflections, and a selective print coating contributes to better adhesion. An aluminium substructure ensures the system’s vibration damping, which

enables further application possibilities, e. g. as a programmable dance floor, indicator of escape routes, or ambient mood lighting in spas. Innovative Façade Applications In the field of innovative building envelopes and structural façade design, exhibits represented current developments and stateof-the art applications. Against this background, self-supporting all-glass structures, a carbonsteel hybrid roof structure, and the newly interpreted stone façade that were transferred into a building envelope of glass bricks, were shown as 1:1 scale mock-ups.

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Amazing projects in glass

Dutch architects MVRDV collaborated with specialist ABT Glass and researchers of TU Delft to advance the design of the building envelope. As an extension of a historic retail store in Amsterdam, NL, the monolithic glass bricks complement the existing façade, providing similar dimensions as the blocks. The innovative building skin enables direct load transfer by using a specifically developed adhesive that achieves the structural bonding. Featuring the reinvention of the classical brick wall by generating a visual impression that resembles a crystal. The title ‘Crystal House’ reflects the project’s unique transformation.

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Amazing projects in glass

New Technologies Advanced glazing solutions, façade innovations, processing methods, as well as new technologies of other industries become catalysts for the building and construction segment. An outstanding prototype was displayed by the German glass processing company Sedak, this was an elliptically shaped yacht glazing. The inspiring unit of 1.28 m by 3.68 diameter showed cutting edge glass manufacturing, providing a single curved, triple-laminated safety glazing that created a fully transparent boat hull. With a 30 mm engraving, the bent line of the glasses runs diagonally, perfectly nestling within the spherical surface of the yacht envelope.

Due to the extreme environmental off-shore conditions, products for the naval industry require high-precision manufacturing and specific quality control to achieve fault-free implementation. In this particular case, a leak testing in 50m depth assured functionality and operability while a pressure load of 50 t/m2 was applied. Consequently, the product obtained the Lloyd’s register certificate.

An exhibit out of the collaboration between glass manufacturer Cricursa and specialist engineering designers

Eckersley O’Callaghan is Vidre Slide. This mockup collates the latest in innovative techniques applied in the form of a 4 m high triangulated glass structure, and forming a 9 m long slide. The design maximizes transparency – utilizing long, tight-curvature glass and minimal, adhesive bonds without mechanical fixings. Vidre-Slide consists of two long glass elements, propped against each other and tied together at their base by a steel structure. The annealed glass is slumped to form 450-mm-radius half cylinder elements. Fabricated as single 9 m long pieces without splicing, they are laminated with

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Amazing projects in glass

2 layers of 10 mm annealed low-iron glass plies and a SentryGlas interlayer. The curved form of the glass is pivotal in realizing the structure’s long spans. Annealed glass is sufficient to withstand the relatively low stresses due to the geometrical benefits of the half cylinder shape, offering better transparency than if tempered glass was employed. The primary connections are achieved with structural silicone – at the apex glass-to-glass mitred joint, and the glass-to-stainless steel pinned supports at the base. The silicone transfers the forces, fundamental to the stability intelligent glass solutions

of the structure, without using mechanical fixings. A detailed Finite Element Analysis approach accurately determined the joint stiffness, required to distribute the stresses safely. The treads are 42 mm diameter extruded glass rods bonded using Transparent Silicone Structural Adhesive (TSSA) on the inside of the shorter glass element. This adhesive provides an almost invisible bond able to resist the shear load from the weight of a person ascending the structure. The technique for forming long, tightcurvature glass was developed by Cricursa in

collaboration with Eckersley O’Callaghan for a project in Hong Kong. Vidre-Slide exemplifies a collaborative approach between engineers and fabricators that tests the practical application of emerging glass technologies. Conference and Architectural Symposium Similar to previous years, the exhibition was accompanied by an architectural symposium with expert lectures, introducing building applications and structural innovations around the material. Under the heading ‘Transparent Building Skins and Digital Planning Processes’, internationally renowned engineers and researchers presented the latest developments of the building and construction segment, as well as projects that introduced solutions of advanced glass research.

A celebration of glass & other structural materials in contemporary building facade technologies

5IVSTEBZ UI .BSDI t )VMMFU )PVTF )POH ,POH The Glass Supper Asia Paciﬁc is presented by Intelligent Publications Ltd (IPL) & China Trend Building Press Ltd (CTBP)

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The Glass Supper Asia Pacific 2017: Hullitt House, Hong Kong A platform for stakeholders in society to meet in an environment of trust and impartiality to debate important issues on the future of architectural glass and facade technology, then put these plans into action. High on the agenda are issues that will prepare the world for a future that promises to be vastly different to the world we know today. Glass Supper Asia Pacific 2017 guests can take advantage of unique and unqualified access to global experts and leaders of the architectural glass and facade industry whose knowledge and insight will help define and set the framework for the future of buildings and human society here on earth. Furthermore, Glass Supper Asia Pacific guests will gain insider knowledge on the ideas, the solutions and the blueprint for intense boardroom discussion, triggering action and industry advancement. Never before has there been a platform with such unprecedented access to Leadership level delegates, government ministers and ultimate decision makers of the glass construction and facade industry. You will witness and take part in face to face communication at the highest level on global issues that really matter, and exactly how these issues affect our daily lives, and life in the world to come.

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Silicone Structural Glazing g – Assessing g Durability y and Performance

Proven Performance that lasts Dr. Andreas T. Wolf, Consultant, A&S SciTech Consulting

Dip.-Ing. Christoph Recknagel, Project Leader, German Federal Institute for Material Research and Testing - BAM

tructural Silicone Glazing (SSG) is a curtain walling method that utilizes a structural silicone sealant to adhere glass, ceramic, metal or composite panels to supporting framing members by means of a peripheral adhesive joint. In SSG curtain walls, silicone sealants serve not only as a weather seal, but also act as a structural bonding element, eliminating the need for exterior retainers and covers (1). In the 1960‘s, the Dow Corning Corporation was a pioneer of this revolutionary technology that opened the eyes of architects to a new

way of designing and realizing pure glass aesthetics: Dow Corning’s first silicone structural glazing project in 1964 involved structurally bonding glass mullions to external glass in order to rigidify the facade structure, increase daylight opening and transparency. With growing interest in this technique, the 1980s saw the SSG curtain walling concept spread rapidly around the world as this glazing method allowed architects new levels of design freedom and offered a unique aesthetic appearance. SSG has become an outstanding success with literally tens of thousands of projects which showcase its aesthetic and performance benefits.

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Silicone Structural Glazing g – Assessing g Durability y and Performance

455 W Fort Street, Detroit. The world’s first four sided silicone structural glazing project, bonded with Dow Corning SSG Sealant, was designed by architects Smith, Hincham and Grylls. Photo courtesy of SmithGroupJJR.

The Challenge: Estimating the Technical Useable Life of SSG Curtain Walls One major concern with adhesively assembled structures in general is the long-term integrity of the structural bond. Therefore, with the aim of ensuring public health and safety, building code authorities in countries like Germany or Austria still require additional mechanical fasteners for four-sided SSG curtain walls to provide safe retention of the infill panel in case of structural sealant failure – unless the technical useable life can be predicted with the help of more suitable test methods. Furthermore, despite their practically proven performance and stellar track record, uncertainty still exists regarding the ultimate (technical) scientific based service-life prediction of SSG curtain walls. Many SSG curtain walls are disassembled and replaced because of aesthetic and commercial considerations long before they have reached the end of their usable life. Still, there is a significant number of SSG curtain walls globally that have now reached 30+ years of service and building owners and code authorities are faced with the task of estimating the residual service life of these structures.

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Ultimately, the underlying questions are, what is the ‘theoretical’ life of a SSG curtain wall – is it 50, 75 or even 100 years – and how exactly will a structural silicone sealant degrade and ultimately fail? Will it be possible to explore time-dependent performance and fatigue as well as failure mechanism - e.g. with the aim to detect fatigue and failure indicators? Can a scientific-based comparable investigation method over a simulated life time period under use conditions come close to reality? And which technical indicators describe normal operation and can be indicators for beginning degradation? In some countries, this uncertainty is responsible for inhibiting the wider use of the four-sided structural bonding technology. Therefore, important issues that remain to be addressed are the prediction of the degradation behavior and the resulting long-term durability of adhesive-bonded structures. The basis to overcome these open questions, however, is firstly a performance-related understanding of the (mechanical) operating principle of each specific SSG solution under super-imposed loading. To describe the operational principle e.g. in mechanical terms, opens up the possibility to detect degradation and

Silicone Structural Glazing g – Assessing g Durability y and Performance

failure with the help of relative changes. The essential challenge that researchers face today is threefold: a. How to develop a test method that allows study of the mechanical operating principle of an SSG solution, independent of the sealant’s material or SSG construction, under superimposed (realistic) loading conditions? b. How to develop durability test methods that provide a better representation of the actual service environment in the laboratory? c. And, how to calibrate laboratory durability test results against actual in-service performance of SSG adhesive joints? Besides the possibilities for a performance-related design of sealant materials as well as whole SSG constructions, another ultimate objective then, is a more realistic prediction of the technical usable life of SSG curtain walls. Two recent studies constitute major steps forward in this direction and, for the first time ever, provide compelling scientific support for service life estimates of SSG structures significantly in excess of 25 years. The findings validate anecdotal evidence gathered from successful field-performance of SSG buildings that have now been in operation for more than 30 years (2).

A Unique Opportunity: Calibrating ETAG 002 Test Requirements Against Actual In-Service Performance In 1985, the southwest facing bow front façade section of a building at ift Rosenheim, an internationally renowned authority in the testing of windows and façades, was installed using the then-novel ‘hybrid’ foursided SSG system. In this SSG design, special toggles engage in U-shaped glass edge spacers located at the periphery of insulating glass units. Regardless of their mechanical fixation to the substructure, toggle-glazed hybrid SSG designs still expose the insulating glass edge seal to structural loads; therefore, an approved structural silicone sealant must be used to adhesively bond the U-shaped retention channel to the adjacent glass panes. The three-story high toggle-glazed hybrid SSG system broke new ground, as it was installed (in regards to the outboard glass panes) without additional safety retainers and without dead load support. Such a hybrid SSG design corresponds to Type IV Glazing listed in ETAG 002, as the structural bond transfers not just dynamic external loads, such

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Silicone Structural Glazing g – Assessing g Durability y and Performance

Originally constructed in 1985, the façade of the ift Rosenheim was structurally bonded with Dow Corning SSG Sealant Photo: ®ift Rosenheim

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Silicone Structural Glazing g – Assessing g Durability y and Performance

“ Jerry Klosowski, Klosowski Scientiﬁc Inc., about the pioneering spirit:

It was an exciting time. There was a spirit of camaraderie in the industry. All of us working together in a community of trust to develop a new architectural concept and prove to the world that it would work.

as wind load, but also the self-weight of the infill panel. However, different from the situation in a regular SSG design, the structural bond in a hybrid SSG system is also subjected to climatic loads, as changes in temperature, atmospheric pressure, and altitude influence the sealed gas volume trapped within the insulating glass unit. In their approval of the structure, the building code authority placed a high value on the documentation of the manufacturing, quality assurance, and installation of the SSG modules as well as on the structural health monitoring of the SSG bond during service. These concomitant studies, conducted by ift Rosenheim, created a wealth of reference data. When the façade was refurbished for improved energy efficiency after 23 years of service, the dissembled SSG structure offered the opportunity of ‘calibrating’ the requirements stated in the European approval guideline for SSG sealants and systems, ETAG 002-1. ETAG 002 was developed by the European Organization for Technical Approvals (EOTA) in 1991 [3-5]. Its comprehensive range of tests and stringent assessment criteria makes ETAG 002-1 a very demanding standard for SSG sealants. The standard defines key provisions for bonding strength and durability of bonding strength of the SSG sealant and, notably, mentions that the provisions made in the ETAG 002-1 are based on an assumed service life of the SSG structure of 25 years. In 2012, after the dismantled façade had been stored in an unheated warehouse for 2 years, Nikolaus Graf, an undergraduate researcher at the University of Regensburg, conducted an experimental and statistical evaluation of the natural aging behavior of the structural silicone sealant installed at the ift Rosenheim façade in light of the ETAG 002-1 requirements (6). Fortunately, the B.Sc. study was supported by the ift Rosenheim, a fact that allowed Graf to compare his data with the previously collected reference data. A key consideration for determining safety in use and, thus, the suitability of a SSG sealant according to ETAG 002, is the stability of cohesive and adhesive properties when exposed to different environmental and aging conditions. Therefore, an important question to ask is whether or not the

” structural sealant that had undergone 25 years of environmental exposure would still pass the requirements of ‘Initial Mechanical Strength’ and ‘Residual Strength’ (now applied to natural aging) as laid out in ETAG 002-1 sections 6.1.4.1. and 6.1.4.2. The aim of the Initial Mechanical Strength tests is to evaluate the bonding strength of the structural sealant when subjected to tensile or shear forces acting on the joint at different temperatures. Temperature-induced variations in the sealant’s properties may lead to a drop in mechanical and bonding strengths. Therefore, ETAG 002-1 stipulates that the mean tensile and shear strength values measured at -20 °C and +80 °C must not drop below a minimum of 75% of the corresponding values observed at +23 °C and that rupture must occur at an average cohesive failure mode of 90% or greater. In the B.Sc. study, test specimens were subjected to destructive tensile and shear tests at -20 °C, +23 °C, +60 °C, and +80 °C. Across the board, the sealant passes both the above mentioned ETAG 002-1 Initial Mechanical Strength requirements with flying colors. The Residual Strength test is meant to determine the durability of the bonding strength. ETAG 002-1 stipulates that the residual tensile strength after all types of accelerated aging tests must still equal or exceed 75% of the sealant’s initial strength measured at 23 °C and that the failure mode after aging must be ≥90% cohesive in nature. Despite 23+2 years of natural aging, the sealant successfully passes the ETAG 002-1 criteria. Such strong performance against key performance indicators at the end of the 25-year service life assumed by ETAG 002 is quite reassuring. It may give conservative building code authorities the added confidence they need to consider future four-sided SSG structures without supplementary safety retainers. The findings of this study are especially remarkable as the silicone sealant used in the ift Rosenheim SSG application, Dow Corning ID200 (a two-part sealant similar to Dow Corning® 983 SSG Sealant), was commercialized long before the ETAG 002-1 guideline was developed and failed to meet its stringent requirements, once this standard went into effect. The inability of Dow Corning 983 Sealant to meet the ETAG

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Silicone Structural Glazing g – Assessing g Durability y and Performance

specification then triggered the development of Dow Corning® 993 SSG Sealant, the next-generation, higher performance successor product, which is capable of passing all SSG standards globally.

Cameron Centre, Tsimashatui. The first four-sided structurally glazed building in Hong Kong, bonded with Dow Corning SSG Sealant

Back to Basics: Developing a Performance-Based Durability Assessment for SSG Sealants Inspired by the results of the case study mentioned above there is still an open question for further acceptance: How can we explore the functional principle and its possible changes in use with the help of an repeatable test standard as a basis for durability estimation accepted by the authorities? In 2012, the German Federal Institute for Materials Research and Testing (BAM), a leading research institute for science and technology, picked up the challenge of developing a performance-based durability test method for SSG sealants that better reflects the actual service environment. The project was executed between 2012 and 2015 and accomplished the following major deliverables [7]: a) Derivation of a realistic environmental and mechanical loading function suitable for accelerated durability testing under the most important SSG-loadings; b) Development of a system test specimen that provides a better representation of the real SSG joint design; c) Design and construction of a test facility capable of simultaneously imposing weathering and complex, multi-axial mechanical loadings on the test specimen independent of sealants nature or constructional design of the SSG-solution; d) Evaluation of the durability of different ‘benchmark’ SSG sealants. The test was designed to reproduce typical environmental exposure and service conditions. Consideration was given for the following loads [8,9]: • Mechanical loads resulting from self-weight, temperature, wind and extraordinary theoretical loadings like human impact loads; • Climatic loads taking into account typical average and extreme temperatures, humidity, the number of rainy days and the average amount of precipitation and solar radiation per year; • Chemical loads resulting from water (rain) and cleaning agents (aqueous surfactant solution). The deformation/stress loading was derived from parametric finiteelement analyses (FEA) of a large-sized SSG glazing unit installed at a height of 50 meters on a building located in wind load zone II considering terrain categories II and III according to DIN 1055-4 [10]. The following assumptions were made in the parametric analyses [XX]: • The SSG glazing module (2.5 m wide and 3.2 m high) is oriented vertically; the unit is structurally bonded on all four sides; the dimensions of the structural bond (sealant’s cross section) are 12 mm x 6 mm; • The SSG system is glazed with either single pane, insulating glass, or stepped insulating glass (3 options) and installed either with or without support of its own self-weight (types II and type IV according to ETAG 002); • The design stress (σdes) of the structural sealant is 0.21 MPa. (So a 50% higher design strength compared to the typically used σdes =0,14MPa to calculate an SSG façade.)

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Furthermore, in order to simulate a human impact on the SSG module, a separate FEA study was conducted to investigate the effect a pendulum impact test according to DIN 18008-4. The multitude of FEA studies allowed the BAM researchers to derive the maximum tensile and shear deformations occurring in the SSG sealant for each loading event. In general, they assumed the worst-case combination of loads (and resulting movements). However, in order to derive deformation parameters for regular loads, they used the load distribution spectrum, as laid out in ETAG 002-1 section 5.1.4.6.5 Mechanical Fatigue. 50 test cycles successfully passed – equal to 50 years actual service exposure Utilizing the knowledge of the life-cycle load profile that was established during the previous research, the BAM researchers subjected the test specimens to repetitive durability cycles. Each durability cycle, which exposed test specimens for 24 hours to simultaneous climatic and multiaxial mechanical loads, was designed to represent one year of actual service exposure. After the completion of 50 durability cycles, the test specimens were subjected to a rapid, complex deformation in order to evaluate the aged sealant’s ability to sustain an accidental human

Silicone Structural Glazing g – Assessing g Durability y and Performance

impact on glass. The impact simulation was then followed by another two durability cycles. Multi-axial mechanical loading was super-imposed taking into account worst loading scenarios.

Larry Carbary, Dow Corning Industry Scientist:

“

Structural glazing today provides a powerful tool for architects to achieve the most incredible building designs. Not only is it a proven method of curtain wall construction, this technique works as part of a complete system to facilitate state-of-theart performance with regards to air inﬁltration, water inﬁltration, thermal performance, seismic performance, impact resistance, longevity and design freedom. This high performance technique is a benchmark for current and future materials regarding sustainability and green construction.

” 76

Simultaneously to the complex, two-dimensional shear and tensile deformations, test specimens undergoing durability cycles were exposed to surrounding temperatures of -10 °C to +60 °C, relative humidity ranging from 20% to 98%, rain events (distilled water) corresponding to a middle yearly rain fall of 620 l/m2, and maximized energy input of UV light (290 to 410 nm). In order to investigate the effect of mechanical fatigue, additional test specimens were kept in the BAM weathering chamber that were subjected only to weathering without movement. Dow Corning® 993 Sealant was chosen by the BAM researchers as one of the benchmark sealants. After completion of the durability test, the system test specimens were cut by water-jetting into standard-sized ETAG 002-1 samples, which were then tested for their residual strength. Table 5 displays the results observed initially (prior to testing) and after completion of the durability test from comparable test sections under comparable test conditions. Tensile and shear strength values along with the corresponding residual strength ratios (after aging) are shown. The data gathered at the completion of the durability test differentiate between test specimens that had undergone simultaneous weathering and enforced movement and those that were subjected only to weathering. This underlines the most important influence of mechanical loading on the durability behaviour and confirms the new approach and testing methodology introduced. Table 5. Tensile and Shear Strength Values and Residual Strength Ratios for Dow Corning 993 Sealant, observed in the BAM Durability Testing Specimen

Initial Weathering Weathering + Movement

DC 993 Sealant Tensile Residual Strength Strength (MPa) Ratio (%) 1.59 1.52 0.95 1.23 0.78

Shear Strength (MPa) 1.18 1.18 0.98

Residual Strength Ratio (%) 1.00 0.83

As can be seen, Dow Corning 993 Sealant successfully passed the ETAG 002-1 criterion for residual tensile strength The substrate adhesion was good and in accordance with the ETAG 002 requirements. Resulting from additional visual bond control only a marginal loss of adhesion was observed primarily at the corners of the specimen. After more than 50 cycles of super-imposed mechanical as well as climatic loading, extraordinary mechanical loads and chemical loading both the sealant and the specific SSG construction still shows performance behaviour according to the requirements.

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Silicone Structural Glazing g – Assessing g Durability y and Performance

“ Karl-Heinz Rückeshäuser, KHR Consulting:

Beside the challenges and hurdles we had to take to establish structural glazing in Europe, it was an exciting time and a pleasure to work with the “Innovators” on implementing this concept in a quite conservative market environment. I am pleased to see how popular this design concept is now after more than 25 years in Europe.

” Such strong performance against key ETAG 002-1 performance indicators after natural and accelerated exposure is quite reassuring. It may give conservative building code authorities the added confidence they need to consider future four-sided SSG structures without supplementary safety retainers. SSG has proven its reliability now for many years, which is a testament to the performance of the structural silicone sealants involved and the implementation of effective quality assurance procedures. Summary and Conclusions Recently, two research studies focusing on the investigation of the durability and service life of SSG structures were completed. Both studies provide compelling scientific support for service life estimates significantly in excess of 25 years. A test method was introduced able to explore the functional principle and with it a test tool for performance-related further advancement of sealant materials as well as SSG construction is given. The findings validate anecdotal evidence gathered from successful fieldperformance of SSG buildings that have now been in operation for more than 30 years.

The long track record confirmed by the ETAG002 test carried out after 25 years and the developed proposal for a performance based durability assessment re-enforce confidence and trust in this structural bonding technique. Equally important to ensure longevity and long-term durability is the quality of workmanship, the structural joint dimensioning, the design requirements itself and the assessment of adhesion and compatibility. Dow Corning provides the well-established Quality Bond™ programme to ensure high quality during application based on regular audits, quality controls and testing during project execution, documentation, adhesion and compatibility testing.

References [1] Klosowski, J.M. and Wolf, A.T., Sealants in Construction, Second Edition, CRC Press (2015), ISBN 9781574447170. [2] Carbary, L.D., “A Review of the Durability and Performance of Silicone Structural Glazing Systems,” Glass Performance Days 2007, J. Vitkala (ed.), 190-193; available online at: http://www.glassfiles. com/articles/review-durability-and-performance-siliconestructural-glazing-systems. [3] EOTA, ETAG 002 Structural Sealant Glazing Systems, Part 1: Supported and Unsupported Systems, European Organization for Technical Assessment, Brussels, Belgium (2012); available online at: http://www.eota.eu/handlersdownloadashx?filename= endorsed-etags%5cetag002%2fetag-02-may-2012.pdf. [4] Lieb, K., “It Keeps Lasting and Lasting and Lasting – Structural Glazing Façade Undergoes Duration Test” [“Sie hält und hält und hält… Structural Glazing Fassade im Dauertest”], Rosenheimer Fenstertage 2013, ift Rosenheim, pp. 49-53; available online at: https://www.ift-rosenheim.de/documents/10180/131529/

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FA_RFT1310_Lieb.pdf/3a91c9a1-c052-423b-b620-bfa96ef12363. [5] Lieb, K. and Krewinkel, H., “23-Year Old Bonded Façade Undergoes Lab Testing – A Historical SG Façade is Subjected to Lab Testing After Actual Service and Displays Amazing Durability” [“23 Jahre alte geklebte Fassade im Labortest – Historische SG-Fassade kommt nach Realtest auf den Prüfstand und zeigt erstaunliche Haltbarkeit“], ift Rosenheim Publication; available online at: https://www.ift-rosenheim.de/documents/10180/131529/ FA_FAS1303_1.pdf/91cafefd-5efd-4463-be98-22b7803e1291. [6] Graf, N., Durability of Structural Sealant Glazing Systems (SSGS) – Material-based, experimental study and statistical evaluation of an ift facade subjected to natural aging in accordance with EOTA ETAG 002-1 [Beständigkeit von SSGS – Materialorientierte experimentelle Untersuchung und statistische Auswertung einer real gealterten ift-Fassade in Anlehnung an die EOTA ETAG 002-1], Bachelor dissertation, University of Applied Science Regensburg (2012).

[7] Anonymous, Structural Sealant Glazing – Evaluating the performance and durability of structural sealant glazing systems under combined mechanical and climatic loads, available online at: http://www.bam.de/en/kompetenzen/fachabteilungen/ abteilung_7/fg71/fb71_geklebte-glaskonstruktionen.htm. [8] Kaatz, R. and Recknagel, C., “Advanced Evaluation of Structural Sealant Glazing Systems by a New System Test Approach”, ASTM STP 1583 (2015), DOI: 10.1520/STP158320140074; available online at: http://www.astm.org/DIGITAL_LIBRARY/STP/PAGES/ STP158320140074.htm. [9] Recknagel, C. and Kaatz, R., “Exploration and Evaluation of the Performance and Durability of SSG Systems by Dynamic– Mechanical System Testing”, ASTM STP 1583 (2015), DOI: 10.1520/ STP158320140064; available online at: http://www.astm.org/ DIGITAL_LIBRARY/STP/PAGES/STP158320140064.htm. [10] DIN 1055-4:2005-03, Action on structures – Part 4: Wind loads. Deutsches Institut für Normung e. V. (DIN), Beuth-Verlag, Berlin (2005).

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Trosifol Structural ® SentryGlas interlayer gets stuck into

The Shanghai Tower The enhanced strength, superior edge performance and visual clarity of SentryGlas® interlayer is key to The Shanghai Tower’s unique twisting double skin glass façade Photo: Kuraray / Youcen

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More than 200,000 square meters of SentryGlas® interlayer is used in the double skin glass facades Photo: Blackstation and Gensler

Laminated safety glass with SentryGlas® ionoplast interlayer – part of the Trosifol® Structural offering - has played a key role in enabling the design of a twisting, all-glass double skin façade on The Shanghai Tower in China — the world’s second tallest building after the Burj Khalifa in Dubai. SentryGlas® interlayer was chosen primarily for its visual clarity in combination with low-iron glass, the enhanced strength it provided to the overall glass assembly, and because it eliminated edge delamination due to the exposed edges of the glass. Completed in 2015, The Shanghai Tower is 632 meters (2,073 ft.) high and has 128 stories, with a total floor area of 380,000 m2 (4,090,000 sq. ft.). The building’s tiered construction is designed for high-energy efficiency and sustainability, providing multiple separate zones for office, retail and leisure use. The Tower takes the form of nine cylindrical buildings stacked atop one another, all enclosed by the inner layer of the glass façade, which completes a 120-degree twist as it rises.

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Between the inner and outer layer of the façade are nine indoor zones that provide public space for visitors. Both layers of the glass façade are transparent, which is unique as most buildings have only a single façade of highly reflective glass to lower heat absorption. The double layer of glass eliminates the need for either layer to be opaque and reduces the need for indoor air conditioning and heating. In recognition of the building’s sustainable design, the owners of the building, Shanghai Tower Construction & Development, received certifications from the China Green Building Committee and the US Green Building Council. In addition, the China International Exchange Committee for Tall Buildings (CITAB) and the Council on Tall Buildings and Urban Habitat (CTBUH) recently awarded its CITAB-CTBUH 2016 China Innovation Award to the Shanghai Tower for its suspended glass curtain wall, which the judging panel recognized as “particularly novel”. The Tower’s architect, Gensler, identified three key design strategies — the tower’s

asymmetrical form, its tapering profile and its rounded corners – which would allow the building to withstand the typhoon force winds that are common in Shanghai. Using wind tunnel tests conducted in a Canadian lab, Gensler and structural engineer Thornton Tomasetti, refined the tower’s form, which reduced building wind loads by 24%. The result is a lighter structure that saved $58 million in costly construction materials. Designed with 20,589 wall panels with 7,000 unique shapes, the double skin glass façade is suspended from above on massive cantilevered trusses and stabilized by hoop rings and struts. The circular inner glass façade required 14% less glass than a square building of the same floor area. The primary reasons for choosing the Trosifol® product SentryGlas® as the interlayer were the enhanced strength it provided to the overall glass assembly and the elimination of any edge delamination due to exposed glass edges in the structural silicone glazing. SentryGlas® also contributed to the overall sustainability of the

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The Shanghai Tower takes the form of nine cylindrical buildings stacked atop one another, all enclosed by the inner layer of the glass façade, which completes a 120-degree twist as it rises. This design reduces wind loads on the building by 24%. Photo: Blackstation and Gensler

tower by allowing a light coating to be used in conjunction with the interlayer for solar control. The choice of interlayer was also an important consideration for the glass laminator, Shanghai Yaohua Pilkington (SYP) based in China and by the façade consultant. Initially, SentryGlas® was specified for the outer skin façade only, but the project scope was later increased to include the inner façade, podium building façade, glass fins and interior balustrades. In total, approximately 200,000 square meters of SentryGlas® interlayer were used in the building. The structure of the outer glass façade comprised of three layers: 12 mm Low-Iron annealed glass + 1.52 mm SentryGlas® interlayer + 12 mm Low-Iron annealed glass. The structure of the inner glass façade comprised of five layers: 6 mm Low-Iron glass + 0.89 mm SentryGlas® interlayer + 6mm Low-Iron glass + 12 Air + 6 mm Low-Iron glass. The most commonly used panel sizes were 2100 mm x 2400 mm and 2100 mm x 4200 mm. For the glass façade, local building codes had to be considered. In China, the “Technical Code for Glass Curtainwall Engineering” (JGJ 102, Revised Version) is currently under review by the Chinese Government. According to this revised

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code, glass facades for schools, children’s play areas and other public buildings must use laminated glass. In addition, the code work specifies “ionoplast interlayers” as the official recommended interlayer for glass-laminated facades (previously only PVB was listed). The code work also advises that Effective Thickness Calculations should use the ASTM-E1300 (Standard Practice for Determining Load Resistance of Glass in Buildings) standard to ensure low probability of glass breakage.

The laminated glass with SentryGlas® interlayer was also subjected to a number of stringent tests, including subjecting the mock-up to a full test regimen for air, water, dynamic wind, structural load, wind loads, and differential structural movements, in accordance with China, US and European standards. The visual clarity of laminated glass was also an important factor. Visual clarity is normally measured using the Yellowness Index (YI), which is a measure of the tendency of plastics to turn yellow upon long-term exposure to light.

Low-iron glass provides improved visual clarity by increasing light transmission and reducing the greenish tint in clear glass that is most apparent when viewed from the edge. Due to its high clarity, SentryGlas® ionoplast interlayers eliminate the undesirable ‘yellow’ or ‘greenish’ tint that affects safety glass produced with conventional interlayers such as PVB, even at the outermost edge of weather-exposed laminates. Not only does SentryGlas® start clearer than other safety glass interlayers, it also remains clearer throughout its life. The interlayer remains clear, there are no adhesives, other laminating aids or additives to be concerned about inside the composite material. With a YI that starts at 1.5 or less (compared to 6-12 YI for PVB alternatives), SentryGlas® keeps its initial clarity after years of service. Please read more in the Trosifol® Laminated Glass News at www.trosifol.com

Disclaimer: SentryGlas® is a registered trademark of E.I. du Pont de Nemours and Company or its affiliates for its brand of interlayers. It is used under exclusive license by Kuraray and its sub-licensees. Butacite® polyvinyl butyral (PVB) thermoplastic film is sold in North & South America and the Asia Pacific region. In EMEA, Kuraray only sells Trosifol® PVB interlayers.

The Shanghai Tower is the tallest building in China, standing at 632 meters (2,073 feet) high, with a total floor area of 380,000 m2 (4,090,000 sq. ft.) Photo: Blackstation and Gensler

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Silicones enabling crystal clear connections

Valérie V alérie H Hayez ayez Dow D ow Corning Corning E Europe urop S.A.

Background A façade is quite literally, the face of a building, the signature of its owner or the architect, with much consideration dedicated to its conception and integration in its environment. Major advances in glazing and façade technology over the past 30 years have enabled fully glazed sustainable designs providing the demanded aesthetics, whilst respecting occupant benefits such as natural daylight and integration of energy efficiency systems.

Structural glazing enables architectural design through the reduction of exposed metal, for example, by using point fixation, reducing sightlines and smoothing the surface texture and tautness of the exterior glass façade. The six metre high glazed areas used in the Museum aan de Stroom (figure 1) forms a stunning gallery which provides panoramic views of the city, including the river and docks. The Museum aan de Stroom has proven to be an exceptionally challenging project due to its complex array of singularly glazed, serigraphed, s-shape glass panels. This unusual design

required the use of deep u-channeled frames to support the large glass panels, which were 5.5 m x 2 m x 12 mm. Dow Corning® 993 Silicone Structural Glazing Sealant was specified for the two sided bonding due to the depth of the joint and its ability to accommodate the full load of the glass in the event of breakage. The vertical edges of the glass were sealed with Dow Corning® 791 Silicone Weatherproofing Sealant. These weatherseal joints are required to accommodate dynamic movements due to thermal dilation and wind load as well as the

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Fig. 1 Museum Aan de Stroom, Scagliola/ Brakkee / Neutelings Riedijk Architects

Fig. 2 ICE Krakรณw Congress Centre, Image courtesy of G Ziemianski.

constant load present due to the proximity of the adjacent glass plates. Although necessary, the structural and weather seal joints which are the connecting elements between the transparent glasses, represent the remaining visible bottleneck in the continued architectural quest to maximize facade transparency and break the visual barrier between the interior and exterior environments, since the adhesives being used are not necessarily both transparent and durable (figure 2).

Fig. 3 Example of Dow Corning TSSA application (Press Glass, Croatia)

Crystal Clear Structural Bonding Silicones In response to the needs of modern architectural trends, Dow Corning has been active for several years in the development of a range of clear silicone bonding technologies.

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Amazing projects in glass Dow Corning® TSSA –Transparent Structural Silicone Adhesive Already well-established for façade exteriors, Transparent Structural Silicone Adhesive (TSSA) is an optically clear and high strength silicone film. With a thickness of 1mm, this adhesive film is designed to structurally bond glass to metal without any additional dead load support. The permanent design load is about 50 times higher when compared to a conventional structural glazing silicone. It enables a flush and smooth design option in comparison to alternative systems that require drilling and mechanical fastening of glass. By eliminating the traditional need to drill through the glass for placement of retaining bolts and the use of gaskets to retain air/gas tightness at the point of fixation, it ensures superior durability and longevity, as the gas-filled insulating glass cavity remains untouched. Therefore, it contributes to a more thermally sustainable insulation of the façade. The single glazed facade of the new production facility of Press Glass in Croatia was secured using Sadev architectural glass components for the point-fixing. Over 2000 points were bonded

Fig. 4 Architectural rendering of 8511 Warner, Culver City California TSSA project, to be finalized in 2017. Image courtesy Eric Owen Moss Architects

by Press Glass to the tempered laminated glass panes, also manufactured in their factories, with TSSA film. A sleek aesthetic and improved transparency is obtained as the glass panes are not breached, thus retaining the integrity of the glass. It also allowed the glass thickness to be

reduced from 25.4 mm to 17.52 mm permitting the weight and cost of the glass to be reduced (Figure 3). Pushing the boundaries of strength and creativity even further, Eric Owen Moss

Fig. 7 Transparent structural silicone adhesive 2400 used as weather seal between mono-lithic glass (10mm thickness) panes

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Fig. 5 Examples of Interior glass-metal bonding using TSSL (pictures from Glas Trösch AG, Switzerland: Swissstep Bond)

Architects designed an unprecedented glass roof for the 8511 Warner Drive project in Culver City, CA. Curved laminated glass half cylinders form the web members of a series of cable trusses, providing a striking structure unequalled in structural glass design (Figure 4). Their pursuit of discovering methods that bring projects to public prominence is evident in this design. The project uses nearly 200 glass cylinders of various lengths ranging from 7ft to 14ft, forming an acoustic canopy over a performance space. The cylinders are annealed, the only glass process available to achieve their tight radius, and therefore can’t be suspended from the structure by using drilled holes and bolts. The top of the tube is designed with conventional structural silicone and a “Yoke” inside the middle of the tube is attached with TSSA. The Yoke is designed to rest on a steel cable supporting the middle of the tube. The Yoke is bonded to curved steel rectangular patches with TSSA. The curved fittings attached to the glass have to be machined to meet the glass that has a 305 mm radius. The engineering challenge is to use the TSSA to resist the rotational and shear stresses between the two halves of the cylinder during wind and seismic events. Dow Corning® TSSL – Transparent Structural Silicone Laminate Similarly, a clear film for interior applications (Transparent Structural Silicone Laminate or TSSL) is also available for point and area lamination. Its durability, high strength and elastic properties show significant advantages, especially in interior applications like structural bonding of stair cases, glass beams or other interior decorative glass connections. The use of TSSL in a glazed staircase is illustrated in Figure 5. A stainless steel L profile has been

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Fig. 6 Aesthetics in glass fin fixation using crystal clear structural silicone hot melt

laminated to the glass stair string using TSSL clear thin high strength silicone film. The assembly of the glass stair to the glass string on site was done with a conventional, manually applied black silicone. This can be now replaced by clear structural bonding, the newly developed Dow Corning® 2400 Assembly Silicone Sealant for pure glass aesthetics. Dow Corning 2400 Assembly Silicone Sealant for crystal clear manual application The latest breakthrough silicone technology is an optically clear, one-component silicone for specific structurally glazed designs, weather sealing and other glass-glass or glass-metal connections, where durable and crystal clear aesthetics is required. The clear Dow Corning 2400 Sealant is a neutral 100% silicone hot melt. The cure is obtained by reacting with moisture in the atmosphere, whereas the high strength silicone films for exterior and interiors (TSSA & TSSL) have to be

factory applied as they need heat and pressure to cure. The dynamic design strength of Dow Corning 2400 Sealant of 0,14 Mpa is similar to the values of conventional structural silicones. Dow Corning 2400 Sealant provides high strength and high elasticity reaching an ultimate elongation of more than 100% at an allowed movement capability of +/-50 %. Due to this high movement capability and elasticity, joint dimensions are thinner than with conventional structural glazing sealants. Whereas structural glazing requires a minimum joint of 12 x 6 mm2, a silicone hot melt joint of 10 x 3 mm2 may be recommended to resist the loads typically occurring in structural glazing applications. Dow Corning 2400 Sealant develops primerless adhesion to, amongst other materials, all substrates approved by Dow Corning for structural glazing. Testing results obtained until now have confirmed the potential of the technology to fulfill the role of a traditional structural

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glazing sealant. The combination of strength and transparency in conjunction with high movement capacity might be especially attractive for glass beams, closed cavity facades, decorative glass bonding, double skin façades or glass-fin applications. Glass-fins are typically bonded to the face glass along the height (long dimension) with a black structural sealant whilst the top and bottom of the glass-fin is mechanically fixed in a U channel profile. Therefore in this kind of application the joint is only subjected to dynamic wind loading and no dead load, making it an ideal application where this technology could bring a clear aesthetic advantage (Figure 6). Using the Dow Corning 2400 Sealant as a weather seal to increase the transparency of a curtain wall seems to be an obvious application (Figure 7). Butt joints sealing two monolithic glasses provide a unique transparency. As the silicone is suitable for interior and exterior applications with a good UV, temperature and weather-resistance, it opens many opportunities to connect glass to glass or glass to metal. Good examples are double skin facades or closed cavity facades, where floating and clear aesthetics can be achieved, which combine structural properties and the weather sealing function. Since it is now possible to replace both the structural and weather seal joints with crystal clear silicone connections, spacers and secondary seals in insulating glass units (IGU) have become the next remaining barrier to achieve perfectly clear façades. Additional testing related to durability of IGUs is indicating that this technology has potential as a secondary seal for specific insulating glazing designs.

Fig 9: Clear light-guide film

First trials (figure 8) have been performed whereby Dow Corning 2400 Sealant was used on the verticals of an insulating glass unit. On the top and bottom horizontal, a traditional insulating glass design is used, with a spacer containing desiccant, butyl and an opaque silicone secondary sealant. This particular set-up will of course limit durability of the system and hence is only suitable for niche applications for exterior and interior clear glass designs. Optical Grade Silicones – Architectural Lighting As can be seen in Figure 8, the Dow Corning 2400 Sealant was combined with a transparent spacer, manufactured with clear, optical grade moldable silicones. These silicones have specifically been formulated for the lighting industry where they are, for example, being injection molded in 3D shapes such as lenses or LED luminaires. Their specific formulation ensures high temperature, UV and weathering resistance without yellowing and guarantees perfectly clear views. Furthermore their scratch resistance is excellent, making them an easy material to handle in a factory. Besides their use for relatively simple linear accessories like spacers and gaskets, optical grade silicones open up a whole new world of architectural lighting for the increasing number of buildings having illuminated façades. Because of architectural, societal and technological changes, lighting design faces extreme challenges. Materials implemented need to be able to resist high temperature developed by LED light sources, be durable over the lifetime expectancy of the façade while being exposed to harsh environmental

Fig 8. First prototype of insulating glass using the clear hot melt on the verticals and as a transparent spacer

conditions. They should not be visible during daytime and be able to follow complex shapes of façades to bring light efficiently where it is needed during nighttime. Within the range of Dow Corning optical grade silicones, one recently developed material is particularly outstanding thanks to its extreme low light attenuation. In combination with its perfect transparency and unique silicone durability, it becomes a perfect candidate to manufacture very thin flexible clear light-guide films able to bring light to the façade where it is needed. First prototypes were manufactured successfully (Figure 9). Currently the light injection and light extraction options are being investigated. Conclusion Strength and durability combined with its unique aesthetics and transparency open up a new dimension in architectural design freedom. As silicon-based structural glazing solutions have gained a ubiquitous role in the modern commercial architectural realm, we can see that the technology and its application have evolved to address the challenges brought forth by more sleek and transparent facade designs. Designs that, in many instances, can only be realized with clear silicone bonding solutions. This unique combination of solutions comprises higher design load capacity, a high movement capability to accommodate joint movement paired with the higher instant strength enhancing handling and productivity. It opens new design options and fabricator benefits which can produce a more visually understated transparency on behalf of well stated architectural design intents.

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Trosifol® premieres new brand strategy at “glasstec 2016” in Düsseldorf Successful realization of the Best-of-Both approach – product creatively showcased in fashion show

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Trosifol® made a big impact at glasstec 2016, when it unveiled its striking new Corporate Design to partners and customers. The Trosifol® umbrella now covers three leading brands – Trosifol®, SentryGlas® and Butacite® – with a shared and forward-looking market brand and a reconfigured image. The Best of Both worlds At glasstec 2014 one of the biggest talking points was the takeover of the Glass Laminating Solutions (GLS) business from DuPont Packaging & Industrial Polymers (E. I. du Pont de Nemours and Company), with Kuraray promising a raft of new corporate activities. Using a Best-of-Both approach, the respective strengths of the two businesses were to be highlighted, leveraged and implemented in a new strategic concept. In order to achieve this and to make the integration process a success story, numerous employees from both divisions have been hard at work, collaborating over the last two years. “It was important for us to select the best that both worlds had to offer and then develop these further. With a great deal of passion and hard work, we have collectively converted former rivals GLS and Trosifol® into a strong, fighting-fit and future-proof business,” says Johanna Krauthauf, a member of the project management team that helped to shape the integration process. The outcome is a unified business unit under the Trosifol® brand umbrella that now offers the world’s biggest and widest portfolio of laminated safety glass films. The impressive new Corporate Design of market giant Trosifol® is now the outward and inward sign of the success of the integration process. “In spring 2016, after a long shared integration journey – with much deliberation along the way – we made the decision to use Trosifol® as the umbrella brand,” explains Krauthauf, Head of Global Branding & Communications in the new PVB division. As the strongest product in the PVB portfolio and with its association – by customers worldwide – with quality and a superior service and customer orientation, there were persuasive arguments in its favor. As a result, Trosifol® is now the new face of Kuraray as the global market leader for PVB and Ionoplast interlayers for laminated safety glass.

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New logo makes difference visible “From now on, the Trosifol® umbrella brand will be clearly visible, with a modern logo, striking key visuals and the slogan ‘Trosifol™ — World of Interlayers’,” says Bianca Schönfeld, Branding & Communications. She continues: “We won’t use separate logos for the other products, as they will all benefit from the pulling power of Trosifol®.”

TV & Sightseeing Tower - Guangzhou Photo: Kuraray

With this self-assured line-up under the brand umbrella, it is now easier for customers to identify with the collective brand name. Customers can make use of the broad product portfolio and can be assured of the back-up from an organization that is unparalleled worldwide. Designers and architects as new target group The glasstec booth visibly demonstrated the architectural aspirations and attracted countless visitors. Impressive projects were showcased, such as the Louis Vuitton building in France, whose curved glass surfaces project like sails above the tree-tops of the Bois de Boulogne in Paris, successfully communicating the impressive properties of Trosifol® products. A special highlight was this year’s customer event, which celebrated the new brand image. Under the motto “Blue Carpet”, the Trosifol® marketing team brought many products – including UV Protection, Black & White and SentryGlas®* – onto the stage in the form of sensational futuristic costumes. At “Ufer 8” right by the Rhine, over 430 guests witnessed an overwhelming light and fashion show in which the Trosifol® products were spectacularly displayed. “You could see the astonishment and delight on the faces of our customers,” says a very gratified Andrea Schröter, Communications & Fairs/Events. “They couldn’t believe that accessories and parts of the dresses had actually been tailored from our products.” Creativity will be an important factor in future talks with customers. “Until now we’ve tended to be creative for ourselves and in direct appeals to customers. With this highprofile fashion show and the transplantation of product solutions into a seemingly alien domain like fashion, we wanted to demonstrate to our customers how much creative potential can be found… even from a manufacturer of films,” concludes Krauthauf.

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All-glass house – a new space for living Philip Wilson Spatiale Limited This paper will present a residential project in France – completed 2014 – fully clad to the façade and roof in translucent glass. The prototype house (Architect: Studio Odile Decq) is characterized by its simple volume and sleek design – a parallelepiped intersected by a longitudinal volume that contains the services function of the house. The house measures approximately 12m x 10m x 6m high with a glazed envelope of approximately 420m2 made up of a double façade of translucent insulated glass units that permits up to 40% light transmission. The structure of the house comprises a steelwork frame of 120mm deep rectangular section that is clad to the front and back with a translucent IG unit to provide thermal insulation yet allow natural light to enter the space. The paper will review the benefits of daylight exposure to the human experience, the operational performance of the building, sustainability and to create energy savings. There will be reference to current national building regulations for environmental and sustainability standards and energy consumption. In conclusion, the paper will compare and contrast the different design solutions and consider a future for glass enclosures as spaces for living.

Introduction Glass enclosures In the last 5 years, we have recorded a trend where structural glass elements replace traditional materials. This dramatic increase is due to increasing interest from architects as well as the transparent yet durable material, resistant to weathering. By using supporting glass structures and frames, like beams and fins, this increases the transparency even further to form all-glass enclosures. Daylighting Daylighting is the act of lighting the interior/ exterior of a building with natural daylight (1). Natural daylight is proved to have positive effects on health, productivity, learning rates, etc… and to provide more healthy and productive work spaces. Study after study has quantified the benefit of daylight exposure. Daylight exposure has been linked to improved employee productivity, student performance, and even the regulation of a person’s circadian rhythm, which drives the all-important wake/ sleep cycle. Beyond improving the human experience, effectively incorporating daylight in the interior, or daylighting, can dramatically improve the operational performance of

the building and create energy savings. The definition of a ‘well daylit space’ is considered a space that is primarily lit with natural daylight and that combines a high occupant satisfaction with the visual and thermal environment with low overall energy use of lighting, heating and cooling. For office work insufficient daylighting is considered as less than 100 lux, useful daylight as between 100 lux and 2000 lux and too much daylight with visual/thermal discomfort for more than 200 lux. Concept design The brief from the client was for a private house 140-160m2 built from steel and clad (walls and roof) with glass, making use of Nanogel® for thermal insulation. The frame of the house would be built from steelwork and clad with glass as the client intended to import these materials from the UK into France. Furthermore, the client has poor eyesight and a building totally clad in translucent material would let the maximum amount of light into the property as possible. The architect is French - Odile Decq who is known throughout the world as an avant-garde architect and she proposed building the house in Brittany, France. In the end more land was available (2000m2) than anticipated and it was decided

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with more natural daylighting and reduced energy consumption. The light diffusion allowed by the aerogel particles will make the glazing unit translucent and will avoid the need for expensive shaders or louvres (sun blinds) that also require some maintenance and tend to change the aesthetics of a building. More natural daylighting and reduced energy consumption (lower utilities costs) allow more architectural freedom.

Figure 1 Original scheme for the 3 glass houses (Architect: Studio Odile Decq)

to build 3 prototype houses of 170m2 floor area and clad entirely to walls and roof with insulatd glass units filled with Nanogel® by CABOT CORPORATION that form cloud-like enclosures with thermal insulation that’s superior to triple-glazing. Cabot’s translucent Nanogel is a hydrophobic aerogel comprising 95% air in nano-sized pores to inhibit heat transfer through the material. The light diffusion

allowed by the aerogel particles will make the glazing unit translucent with more natural daylighting and reduced energy consumption. Cabot’s translucent Nanogel® is a hydrophobic aerogel comprising 95% air in nano-sized pores to inhibit heat transfer through the material. The light diffusion allowed by the aerogel particles will make the glazing unit translucent

Figure 2 Perspective of 3 houses looking from West (Architect: Studio Odile Decq)

Detailed design and calculations The 3 houses are characterized by their simple volume 12m x 10m x 6m high and architectural respect for each other. Each house is a variation on the same theme: a parallelepiped intersected by a longitudinal volume that contains the services function of the house. A floor surface area of 170m2 compares to a glazed envelope of 420m2 made up of a double façade of translucent double glazed units and solar control PVB film that cuts out 40% solar heat (IR) energy, giving an exceptional thermal performance. The calculated overall U-value for the façade and roof was 1.09 W/m2K and solar gain of the façade of 0.31 and roof of 0.21.

Criteria U-value

1.09 W/m2K EN 673

40% Total light transmission

Solar gain

31% Façade 21% Roof

Table 1 Calculated performance values of the double skin façade and roof

In the final project the Nanogel® was replaced with a translucent glass fibre insulation material, which enhances the thermal insulation (U-value) and offers sun protection, because it reduces solar heat penetrating the window in the summer. Due to the effect of scattering light even deep rooms can be illuminated evenly, without blending and shading. The material is UV-stable, temperature resistant up to 100°C and insensitive against humidity. It is easy to install as it fills the space between the double glazing unit completely.

Figure 3 Perspective of 3 houses looking from East (Architect: Studio Odile Decq)

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Figure 4 Perspective of steelwork structure supporting glazed façade & roof units

Building regulation The French building regulation RT 2005 that came into force in September 2006 require an Energy Consumption (CEP) lower that the reference (CEP ref). The maximum summer tempera-ture Tic must be lower than a reference value Tic ref. Despite the above values being greater than the specific requirements for U-values of walls of 0.45 W/m2K and roofs of 0.34 W/m2K, the provision of a ground source heat pump resulted in a C value of 159 kWh/m2 cf. C ref of 163 kWh/m2 and a Tic of 64 °C cf. Tic ref of 68 °C.

Construction

Figure 5 and 6 Site images during construction

Figure 7 and 8 Exterior images taken May 2015

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Figure 9 and 10 Interior images taken May 2015

Building accreditation In the US The Leadership in Energy and Environmental Design (LEED) relates to environmental standards for sustainability, efficiency, and indoor environmental quality. Of the 57 available credits, one involves daylighting. Specifically, one credit can be obtained by ensuring a minimum of 2 percent daylight factor over 75 percent of the floorspace. LEED is similar in spirit, though different in detail, to the Building Research Establishment Environmental Assessment Method (BREAM). In the UK, the British Council for Offices has published a guide to “Best Practice in the Specification for Offices”. It requires a minimum daylight factor of 0.5% with an average of 2-5%. Part L (2002) of the UK Building Regulations allows an exemption from lighting power density requirements for spaces which are “daylit”, ie. which have a daylight factor of 2 percent over 80 percent of the floor area.

Performance

Figure 11 Temperature readings (Winter)

Figure 12 Temperature readings (Spring)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5

Outside=7000 lux Outside=5000 lux Outside=5500 lux Outside=6800 lux Outside=6600 lux

Table 2 Light transmission values

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Inside Patio=3500 lux (50%) Inside Patio=2900 lux (58%) Inside Patio=3300 lux (60%) Inside Patio=3500 lux (52%) Inside Patio=3500 lux (53%)

Inside house=1500 lux (21%) Inside house=1000 lux (20%) Inside house=1300 lux (24%) Inside house=1200 lux (18%) Inside house=1400 lux (21%)

Conclusions As structural consultants we have seen an increase in size and complexity of glass structures related to residential use. The mechanics and safety of these structures have been proven and environmental standards have been respected. At Spatiale we combine consultancy on structural analysis with energy performance to give an integrated design service. National standards will become a lot more demanding: in the UK 2013 and 2016 Building Regulations will require a 44% and 150% emissions reduction, respectively, and in France the RT 2012 envisage a maximum consumption of 50 kWh/m2/year. Glazing coatings & films will need to continually improve to satisfy these future standards.

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Attaching insulated glass to buildings, what are your options? Louis Moreau, AGNORA, Collingwood, ON, Canada Franklin Lancaster, Eckersley Oâ&#x20AC;&#x2122;Callaghan, New York, NY, United States Abstract Five commercial glazing system analysis and a project study show the advantages of using Insulated Glass Unit (IGU) edges to mechanically attach glass to buildings. Introduction Dry glazing with pressure plates and spider fittings have been used for decades. Development in silicone chemistry enabled Structural Sealant Glazing (SSG). This technology triggered an architectural trend where the building envelope conveys a seamless image. Glass panels are mounted side by side, without separation, concealing the supporting structure. The SSG technique requires a lot of operations and quality control and is very difficult to perform on site. It superimposes silicone and aluminum that are already components of structural IGUs. Facade system makers developed ingenious ways to use the IGU edges to allow mechanical connections between glass and the structure as a substitute to SSG.

Systems

QUATERNARIO -PERMASTEELISA Principle Full perimeter mill finish aluminum frame integrated in the sealant bead. The internal lite is stepped back to provide a large bonding area for the front lite. This assembly can be made on the automated IGU assembly line. The original patented design presented here allows snapping on frame. More recent version provides screwing capabilities. Challenges Because of the complex automated assembly and extra equipment required to assemble automatically, very few fabricators can produce Quaternario IGUs. The design of this system requires a large sight line. Manufacturing Both inner and outer lites have different sizes and their dimensional tolerance needs to be Âą1 mm. Aluminum cutting and mitering are required to assemble the frame. Finally a special silicone application head has to be used to inject the silicone in a narrow opening.

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FW 50 SG – SCHÜCO

VGG – REYNAERS

Principle The classic Schüco system uses a special IGU spacer bar that comprises a U channel attached or molded to the spacer box. This creates a continuous channel on the whole perimeter of the unit. Threaded toggles or glazing clips are used to attach the middle of the profile to mullions. Schüco also offers a pocket system.

Principle A full perimeter thin mill finish aluminum V profile is attached to the back lite of the IGU. Long and thin interlocked strip inserts into the cavity to attach to the profile.

Challenges The standard aluminum spacer has thick walls and high thermal conductivity.

Manufacturing Installation of the perimeter extrusion is done manually and is time consuming. During assembly, a double-sided tape is used to hold the profile before and during the sealant application. Foam bead preventing silicone to contaminate the groove needs to be removed after sealant has cured.

Manufacturing The horizontal top corners assembly requires milling equipment for the spacer. A special silicone application head must be used to inject the silicone in two narrow cavities without filling the middle one.

Challenges Larger sightline: the profile height (10 mm) is not considered structural

VARIO – ECKELT

SKANDINAVISKA

Principle VARIO uses a 100 X 12 X 8 mm stainless steel U channel that is embedded or suspended in the middle of the silicone joint. Those fixation points are spaced 400 to 600 mm apart on the perimeter.

Principle 100 mm waterproof plastic pockets are embedded in the silicone joint and spaced apart from 200 to 600 mm, depending on wind load. Several types of pockets offer shallow or deeper retention area. The IGU is mechanically fixed back to the facade construction by means of the 25-30 mm retractable tabs and a threaded restraint.

Challenges Top horizontal channels can fill with stagnant water Manufacturing The pocket is inserted after normal automated sealant application. Correct positioning of the clips requires a jig and skilled workers. Silicone reflow inside the channel can be awkward.

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Challenges Fixed 15 mm spacer Manufacturing The IGU assembly is done on a normal automatic line assembly. The self-centering plastic or composite pockets are pushed into the fresh silicone at the end of the line. This expels only the clip’s volume of sealant.

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Case study

pressure caps suggested either a fully structural silicone approach or a toggle system.

H&M 5TH AVENUE, NEW YORK. The H&M store was completed in July 2014. It consists of large format insulated units (typically 3.5x2.2 m) supported by structural glass fins. The triple laminated glass fins with a total height of approximately 13.5 m are spliced in two locations and carry the vertical load from the facade IGU panels. The architectural requirements to have minimal and clean sight lines with no discrete point or patch fittings or 96

Whilst fully structurally bonding the facade panels to the glass fins with silicone potentially looks simple, it has several drawbacks such as ensuring sufficient structural bite to transfer the applied loading, large amounts of on-site silicone work and difficult replacement. Beyond the typical drawbacks of a full-fledged SSG system, one of the biggest challenges of this project was lateral drift of the building

under wind load. Under this induced movement, the facade panels rotate about their support points, which causes differential vertical displacements in the joint between two adjacent panels. If the facade panels were attached to the fin directly with structural silicone, then the shear force generated in the silicone would be too high. For these reasons, the Skandinaviska clip system was used to laterally restrain the panels, meaning that all the silicone joints could be low modulus weathersealed type

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capable of accommodating the required strain. Furthermore, the custom Skandinaviska channel could be structurally bonded to the glass fins in the factory under controlled conditions, ensuring a high quality bond, and delivered to the site ready for the IGU panels simply to be mechanically fixed in place. This led to a very quick installation process and high quality finish with minimal sight lines.

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A Comparison of the Thermal Transmittance of Curtain Wall Spandrel Areas Employing Mineral Wool and Vacuum Insulation Panels by Numerical Modeling and Experimental Evaluation D.W. Bettenhausen a,*, L.D. Carbary b, C K. Boswell c, O.C. Brouard c, J.R. Casper a, S. Yee b, M.M. Fukutome c (a) Enclos, 2770 Blue Water Rd., Eagan MN 55121 (b) Dow Corning Corporation, PO Box 994, Midland MI 48686 USA (c) Skidmore Owings and Merrill LLP, One Front St., San Francisco CA 94111

Abstract: Research was performed to establish the merits of utilizing fumed silica vacuum insulation panels (VIP) and aerogel enhanced fabrics in the construction of curtain wall spandrel areas; specifically, with the aim of considering potential performance improvements and novel esthetic possibilities. In doing so, a thermally isolated framing system adapted from plans for a commissioned building was chosen as a benchmark and detailed according to conventional practices commonly employed for unitized curtain wall construction. Spandrel assemblies incorporating this framing system with various applications of insulating materials were evaluated by the FEM (finite element method) and compared to results obtained from experimental evaluation. Respectively the software program Therm 6.3[1] and the ASTM C 1363[2] procedure were used with NFRC100 [3] environmental conditions. With regard to geometry, two unique compositions were employed for the study consisting of both a spandrel area isolated from adjacent vision areas and spandrel area with adjacent vision areas above and below the spandrel. In the latter case, both a fixed head rail and stack joint were included. The physical dimensions of the samples varied from 900mm x 1500mm to 1500mm x 2130mm (3 ft x 5 ft to 5 ft x 7 ft). The results of the work established that thermal modeling techniques can be proven to predict spandrel area thermal transmittance with reasonable accuracy when compared to an accepted industry test standard. Furthermore, the merits of the innovating the insulation technologies proposed are addressed quantitatively and the results are projected for a range of typical curtain wall assemblies.

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1.) Introduction Energy Code requirements, such as those in ASHRAE 90.1[4] and the International Energy Conservation Code (IECC)[5] set requirements for the minimum level of thermal performance that curtain wall systems must achieve. In many cases today’s floor to ceiling “all glass” buildings, which have become ubiquitous of commercial construction, fail to satisfy these objectives. Architects want to increase the portion of the envelope that is vision glass because they perceive that doing so will enhance views and increase daylighting. In many instances, the only reason that architects accept the integration of spandrel panels is because they are required by building codes to achieve floor to floor fire separation [2015 IBC section 705.8.5]. There is an unsatisfied need expressed by designers for wall components that either improve the thermal performance of the vision glazed area, or provide a better performing non-vision component that taken in aggregate will allow for the increased use of vision glass while also satisfying code requirements. The resistance of spandrel has been reported in literature; however, both the methodologies applied and results obtained vary. Of critical interest is the effect of “thermal bridges” through insulating elements which can be analyzed with varying degrees of fidelity. Though such differences exist, model energy codes do not favor a particular approach, and it is not clear how the basis for performance reflected by code has been established. While this can be said of spandrel (non-vision) areas, consensus standards for vision areas do exist and have enjoyed widespread adoption. It is natural to question if such standards can be adapted for the evaluation of spandrel areas? Historically, industry practice pays homage to a relatively narrow range of insulation products. With regard to curtain wall, the venerable mineral wool insulation panel has been privileged with wide spread use while the prospect of their being an alternative has largely been ignored. This incumbent philosophy speaks to a multitude of factors such as the low cost of mineral wool and its desirable material properties. For instance, fire resistance, thermal insulating quality and durability have been established based on extensive past use. To challenge this established choice, alternate insulation products will need to go to great lengths to establish their merits. The essential chemistry that gives rise to the performance of the vacuum insulation panel (VIP) evaluated in this study has its basis in the use of fumed silica held under a vacuum. Owing to special thermal properties which are discussed thoroughly in the literature, this combination provides an effective thermal conductivity that is far less than air at standard pressure and temperature [6]. It serves to note that most conventional insulation products, such as mineral wool, derive their insulating quality by trapping small pockets of air within a lattice of material. Thus, the thermal conductivity of air is a limiting bound on their performance. This performance is diminished by small-scale convection and radiation which occurs in the air voids as well as heat conduction through the lattice material. To create the core material the fumed silica was mixed with an opacifier, to reduce radiant heat transfer, and a binder to hold it together during processing. The mixture is heated to remove any moisture vapor, cut to size, and placed in a multi-laminate foil bag. The bag is placed under vacuum of 1-4 mBar and heat sealed. The superior thermal performance

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of the vacuum insulation panel is based on the vacuum eliminating convective heat transfer through the core. The silica core is known for its thermal performance due to its extremely small kernel size and microporosity. Another feature of the fumed silica core is that it allows excellent performance as atmospheric gases slowly diffuse through the seals. Non silica cores made into VIPs (vacuum insulation panels) are intolerant of the smallest diffusion of atmospheric gasses. Larger VIPs are desirable compared to small ones because the multilaminate foil bag in itself is a thermal bridge. Small size panels are not as thermally efficient compared to large panels due to the thermal bridging of the multilaminate foil. Fumed silica VIPs start with a thermal conductivity of about 4mW/mK and after 25 years may rise to 7mW/mK. This increase in thermal conductivity is due to atmospheric gas diffusion into the core allowing a small amount of convective heat transfer. However conventional insulation materials are unable to compare to these extreme low thermal conductivity values. [6] VIPs are commonly used in high performance refrigeration for both in home and transportation applications along with small size shipping of refrigerated items. VIPs have been in use in construction applications in Europe the longest due to energy costs in combination with strict building codes. VIPs in construction in North America are new, with experience and understanding of the use in Canada exceeding that of the United States. [7] The study described herein in a multi-disciplinary effort conducted across industries to establish the thermal performance of a curtain wall shadow box based on contemporary framing design, with the aim of considering different insulation assemblies which feature vacuum insulation panels. Key objectives include determining the adequacy of analysis methods prescribed by standards for vision areas to evaluate shadow boxes, to establish the performance of the assemblies experimentally and to compare the use of systems incorporating VIPs to those which feature conventional mineral wool insulation. It is the hope of those who have partaken in the effort that the results will contribute to the evolution of technologies and practices. Conventional mineral wool insulation is quoted to have a thermal conductivity of 0.034 W/mK. The VIPs will start with 4mW/mK and age to 7mW/mK. [6] At the final aging the VIPs are between more costly R value per inch basis on an area basis. The additional costs for the VIP has to be accounted for by capturing the value in the reduced thickness required to achieve the desired or required system thermal performance. 2.) The Physical Assembly 2.1 Tests A, B & C – Variations on the Curtain Wall Framing It was deemed appropriate to model and test realistic assemblies in the, “hot box” chamber to confirm their inherent constructability and thermal performance. For this purpose a total of twelve samples were created as will be described in this section. With specific regard to the insulation products used there are four options that were chosen for the study. In particular, a “baseline case” which uses a liberal application of mineral wool to represent typical practice was compared against three variations of the VIP product. These variations were chosen on a basis of fire code requirements, esthetics and performance.

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Although it is not a constant, typical curtain wall assemblies that are representative of the built environment are commonly 1524mm (5 ft) in span and one story in height, 3962mm (13 ft). Unfortunately, these dimensions conflict with the guarded area of 2438mm x 2438mm (8 ft x 8 ft) defined within the context of ASTM C1363 and that is generally reflected in practice by most labs. Subsequently, the design of the assemblies tested needed to be shortened with respect to their height dimension. The area of interest to the authors is specifically the opaque section of the curtain wall; namely, the “shadow box” which consist of a recessed finish panel backed by insulation that is recessed from a transparent insulated glass unit (IGU) at the exterior surface. Typical shadow boxes in a highly transparent glass office building are 914mm x 1524mm (3 ft x 5 ft) and a vision lite would be 1524mm x 3048mm (5 ft x 10 ft) resulting in a window to wall ratio (WWR) of 77%. It may not be uncommon to decrease the WWR to 61% by reducing the glass height to 2438mm (8 ft) and increasing the height of the shadow box to 1524mm (5 ft). Opaque assemblies of 1524mm x 1524mm (5 ft x 5 ft) have been studied and modeled previously [8][9] in this same spirit, however the assemblies studied were not shadow box designs. Given the history, the constraints of the test apparatus and the typical dimensions used in the industry today, the team of authors determined three assemblies would be used, as noted as Test A, Test B and Test C. This is outlined in Figure 2.1. Test A represents a fully-framed shadow box that is placed between two fully-framed vision areas located above and below the shadowbox. The total height of this assembly is 2133mm (7 ft). It includes a curtain wall stack joint, and a stationary horizontal transom respectively above and below the shadowbox. With regard to the extents of the specimen where it interfaces the chamber surround, split vertical mullions were included at the jambs and stationary horizontals were placed at the head and sill. This test was included to account for the full effect of the transition framing between vision and spandrel. Test B is a fully-framed shadow box assembly with dimensions of 914mm x 1524mm (3 ft x 5 ft). The stack joint and horizontal rail above and below the test sample were modified to fit the chamber as detailed in Figure 2.2. Note that the shaded region indicates where the insulation assemblies were placed. These assemblies will be discussed extensively in the proceeding sections. The purpose for including this test assembly was for comparison with Test A to determine whether or not including the adjacent vision sections has a meaningful impact on the test outcome. Test C is a shadow box assembly with dimensions of 1524mm x 1524mm (5 ft x 5 ft). Aside from the increase in height this sample is identical to Test B previously described. The purpose of this sample was for comparison with the outcome of previous tests. [8][9] 2.2 Options 1, 2, 3 & 4 – Variations on the Shadow Box Insulation Furthermore, four insulation configurations were tested in framing systems A, B & C and will be furthermore referred to as insulation options 1, 2, 3, and 4. These assemblies are highlighted in Figure 2.3. On the left hand side of the figure the insulation panels are shown at the center of the assembly. The outermost IGU shown in each case is 25mm (1 in) in thickness consisting of two 6mm (¼ in) clear glass lites with a 12.7mm (½ in) air cavity and a low-E coating on the second surface. In particular, a

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double-silver low-E was used. The specific insulation configurations will be discussed. On the right hand side of the figure the jamb condition corresponding to each case is also shown. These images depict the application of supplemental insulation over each mullion. Vertical mullion wraps, as they are known in industry, are generally applied to mitigate heat loss through the frame and supply fire protection. Insulation option #1 represents the, “baseline” case and is a benchmark based on conventional shadow box design as it is currently practiced. The depth of the shadow box is 74mm (2.9 in) in front of the metal panel and 100mm (4 in) of mineral wool insulation. Insulation option #2 incorporates a 19 mm (¾ in) vacuum insulation panel in conjunction with 51 mm (2 in) of mineral wool insulation placed interior to the VIP. The recessed dimension of the finish panel within the shadowbox is 107 mm (4.2 in). The intent of this assembly was to match the thermal performance of the assembly #1 while retaining the mineral wool layer to maintain similarity with fire rated assemblies. Insulation option #3 incorporates a 25 mm (1 in) vacuum insulation panel. Note that in order to protect the VIP (vacuum insulation panel) that a 0.635mm (24 gauge) galvanized steel panel is affixed at its interior surface. The extent of this panel was held back from the framing to avoid thermal bridging. The depth of the shadow box is 155mm (6.1 in) in front of the metal panel and the vacuum insulation combination. The spirit of this assembly is to match the thermal performance of the assembly #1 and provide the deepest shadow box assembly possible. Vertical mullions were clad in 10mm (3/8 in) of aerogel insulation. Insulation option labeled #4 incorporated a metal bathtub shadow box at 94mm (3.7 in) depth. 20mm (¾ in) of Aerogel insulation surrounded the metal tub. The Bathtub was placed over 80mm (3 ¼ in) of vacuum insulation panels clad in in the 0.635 mm (24 gauge) metal. The metal tub was attached to the interior vertical and horizontal frames with structural silicone. The extent of this panel was held back from the framing to avoid thermal bridging. The spirit of this assembly was to maximize the thermal performance of this system by using a maximum thickness of high performance insulation and using a standard shadow box depth. Vertical mullions were also clad in 20mm (¾ in) of aerogel insulation. A total of 12 assemblies were fabricated and tested based on all possible combinations of the tests and insulation options described. Distinction of tests A, B & C and the insulation options 1-4 have been described as such to establish a nomenclature. For instance, Test B3 corresponds to insulation option 3 in framing system B. Since no anchoring system is present within the test chamber it was necessary to surround each case with a structural wood frame in order to hold the samples together, in particular for Test A which features the moving joint. For consistency, and to facilitate ease of handling of the samples, this practice was carried out for all of the tests. Thermocouples were attached during the manufacture of each test so that temperatures of the test could be compared to models. The hot box results represent the total assembly that includes the wood frames. Thermal modeling was used to predict what the performance of the entire assembly and center of frame to center of frame performance.

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Figure 2.1: Dimensions in Elevation of the Curtain Wall Framing for Test Cases A, B & C

Figure 2.2: Respective Head and Sill of Shadow Box Conditions for Tests A, B & C

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Figure 2.3: Insulation Options 1 through 4 Placed with Framing Assemblies A, B & C

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3.) Numerical Model 3.1 Historical Context and Current Practice So far, as analytical methods of evaluation have been applied to quantify the thermal performance of building envelope systems a distinct legacy is embodied by domestic and international standards such as those prescribed by the International Organization for Standardization (ISO) and American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE). Methods adopted hail to a steady-state model of heat transfer which relies upon an analogy between thermal processes and electric circuits. This, so called, “thermal resistance model” assumes that the thermal capacitance of each envelope material is negligible and that a given construction is represented by a network of distinct thermal resistance elements which are analogous to electrical resistors. Corresponding to each element a rate of heat transfer Q flows onedimensionally from a node of higher temperature Tn to a node lower temperature Tn-1 at a rate that is proportional to the temperature difference of the nodes Tn - Tn-1. As with electrical circuits a scalar constant of proportionality relates the rate of heat transfer through the element to this temperature difference. The reciprocal of the proportionality constant is an element property referred to as its thermal resistance of the element. This relationship, and the accompanying mathematical relationship, is described schematically in Equation 1.

Equation 1: Thermal Resistance Element A utility harnessed by this simplification of heat transfer is that the great array of analysis methods which have been developed for electrical circuits can be applied to heat transfer occurring within a network of materials. Borrowed from electric circuit analysis is the concept of an, “equivalent circuit.” An equivalent circuit is a simpler circuit which exhibits the same behavior as a more complicated circuit when placed between the same two nodes. The equivalent circuit contains only a single resistance which represents the effect of the combined resistances acting as a network. It is well established that the equivalent resistance of two resistors placed in parallel between two nodes is the reciprocal sum of the individual resistances. When resistors are placed in series between two nodes the equivalent resistance is the sum of the resistances. In the parlance of mechanical engineering the equivalent resistance of a, “thermal circuit” is referred to as an R-value. It is also common to describe the relationship between temperature difference and rate of heat transfer as a conductance defined as the U-value (1/R-Value). From a standpoint of evaluating potential building envelope products for a given application, determination of the equivalent R-Value or U-value corresponding to the total assembly of components provides a holistic metric which describes the overall performance of the product as the aggregate of its individual parts. Subsequently, the aim of any thermal resistance model is to identify individual elements within an assembly and how they are networked so that an equivalent resistance can be determined.

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How a given construction is decomposed into resistance elements and how those elements are networked relies on choices that are inherent to a given standard and bear a significant impact on the fidelity of the overall result. An investigation of every popular method commonly employed in practice exceeds the scope of this paper. With regard to the specific study at hand the methodology used was based upon the ISO15099 [10] standard which is adopted in the National Fenestration Ratings Council (NFRC) Procedure 100 [3]. Specific details are available in print from these respective authors. The ISO procedure embodies the construction of a window. For a given frame nine distinct resistance elements provide parallel paths for heat flow. Those are: 1.) The resistance corresponding to the center area 2.) The four edge resistances corresponding to the head, jambs and sill areas 3.) The four frame resistances corresponding to the head, jambs and sill areas

Figure 3.1: Thermal Resistance Network Corresponding to a Window

These resistances are shown in Figure 3.1. Distinction of each window area associated with a given element as an independent entity relies strongly on the assumption that the resistance embodied by that area is distinct with regard to the driving temperature difference and not in any way inter-related with heat transfer occurring at other elements. In corollary, heat transfer cannot occur between the areas allocated to each element. Heat transfer can only occur 1-dimensionally at each element per the expression shown in Equation 1. Corresponding to each zone the method of analysis used to determine the element’s resistance differs. In particular, the “center element” calculation adopts a distinctly different approach than the “frame and edge” element calculations. In the former case heat transfer is not thought to be strongly affected by multi-dimensional effects; whereas, in the latter cases, 2-dimensional effects are presumed to be important. Furthermore, the modeling of thermal radiation is different in each case. Glass is a spectrally-selective semi-transparent media and subsequently

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the center calculation must account for spectral dependences if they have a significant effect on heat transfer. Such is commonly the case when radiation of solar origin is incident on glass resulting in significant transmission between layers at a, “favored” spectral distribution. Framing areas, on the other hand, are generally composed of opaque materials that do not exhibit spectrally selective transmission. Radiation exchanges therefore do not need to account for transmission of radiation through materials and can rely upon more rudimentary assumptions. 3.2 Model of 1-Dimensional Heat Transfer at the Center of Spandrel For the present case the complexity associated with solar transmission is not explored and further research is required to establish radiation effects which are inherent to that case. The resistance corresponding to the center of area is derived from a 1-dimensionsal series resistance model where the resistance of each solid material is determined solely by its thickness and thermal conductivity. The resistance is simply t/k where t denotes the material thickness and k denotes thermal conductivity. For gas spaces an equivalent resistance is determined based on an empirical correlation which involves convective and radiative coefficients. A detailed explanation of the method used is shown in section 6.6 of the ISO15099 [10] standard. 3.3 Model of 2-Dimensional Heat Transfer within the Frame The resistance corresponding to both the frame and edge is derived from a single 2-dimensional model with a solution space corresponding to the cross-sections of the head jamb and sill as shown in Figure 3.2. This solution space is terminated laterally at the interior and exterior surface of the wall. The longitudinal extents are carefully placed at locations where adiabatic planes can be thought to exist either as a result of symmetry or abutment with highly insulating materials.

Figure 3.2: Solution Domain and Boundaries Within the solution space an equation of heat transfer is approximated by finite element method discretization of a partial differential equation. In particular, Laplace’s equation, Equation 2 is observed as the governing equation.

Non-adiabatic boundary conditions account for convection and radiation. Convection is established from a fixed heat transfer coefficient which approximates the effect of fluid motions that are not solved for. Radiation is determined based on a view factor calculation for interior surfaces and assumes a view factor of unity for exterior surfaces. In both cases, a temperature corresponding to far field convection and far field radiation must be independently specified. The degree of freedom of the finite element model is temperature. The outcome of a given simulation is the spatial temperature distribution corresponding to all locations within the solution space. From the temperature distribution and material conductivities the rate of heat flux occurring at each location are also solved for. 3.4 Material models The solution to Equation 1 requires that a thermal conductivity be defined for each material in the solution space and that the nature of heat transfer occurring is diffusive according to local temperature gradients. That is to say, that the physics embodied represent heat conduction. Any trained observer will quickly point out that other modes of heat transfer will be present within the cavities of the frame where convection and radiation also take place. In order to account for this limitation the solution methodology employed relies upon the concept of an “effective conductivity” which is thought to represent these effects to some degree. Specific details outlining this approach are available within the ISO15099 [10] standard. 3.5 Post Processing of Numerical Results The portion of the frame in cross-section which extends from the centerline of the mullion to the sightline is the, “projected frame dimension.” With regard to materials placed within the framing, whether they be glass or insulation, the first 63.5mm (2.5 in) in length adjacent to the frame is the “projected edge dimension.” Multiplication of the frame dimension and the span of that given frame component result in the “projected frame area.” Similarly a “projected edge area” corresponds to the edge dimension. A center area corresponds to the portions of a given window within the framing and edge areas. The goal of the post processing effort is to determine the rate of heat transfer occurring through each projected area so that, taken in combination with the known area and known interior vs. exterior temperature difference, the conductance of that component can be determined. Based on the simulation outcome for the Therm 6.3 [1] 2-dimensional model cases this result is easily obtained by summing the rates of heat transfer entering at each cell along the interior boundary for portions of the boundary which fall within the frame and edge dimensions described. For the 1-dimensional model case the resulting rate of heat transfer is used. 4.) Experimental Procedure The twelve specimens assembled in the curtain wall fabrication facility had Type T thermocouples placed in identical positions. The wires for the thermocouples were routed out through holes drilled in the assembly and also through the wet sealants use to attach and seal the vision glass to the framing. Care was taken to keep the wire penetrations through

Equation 2: Laplace’s Equation

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framing and seals air tight. Thermocouple wires were also routed behind backpans. All thermocouples were labeled and accounted for during the hot box testing. Thermocouples were carefully placed and taped so that intimate contact with the surface was achieved. See Figure 4.1.

Each test requires that steady state temperatures must be maintained for two four-hour periods. The results are based on the measured heat flow through the specimen during these steady state periods. The tests were performed at Architectural Testing, Inc. (ATI) test laboratory in St. Paul Minnesota. Figure 4.3 shows a specimen 1B mounted into the XPS with thermocouple wires. Thermocouple wires are noted to be penetrating the wet seals surrounding the glass on the cold side.

Figure 4.1: Type T thermocouples taped down with foil tape to ensure surface contact.

The testing used boundary conditions found in ASTM C1363 [2]. The exterior (cold side) temperature was -18C (-0.4F) with a 6.7 m/s (15 mph) wind which had an exterior film coefficient of 29.98 W/m2K (5.28 Btu/hr ft2 F). The Interior (warm side) temperature was 21 C (69.8F) with a 0.02 m/s (0.05 mph) with a warm side coefficient of 6.52 W/m2K (1.19 Btu/hr ft2 F). The guarded hot box incorporates a metering chamber. Figure 4.2 is a typical schematic detail of the guarded hot box assembly. The climatic chamber, and metering chambers are maintained as noted above the system is calibrated with 200mm (8 in) thick Extruded Polystyrene (XPS) foam separation between the climatic and Guard chambers. The XPS has a known thermal conductivity, thickness and overall U value. During this time the metering box loss is carefully measured. The XPS foam was cut to accept and test specimens 1B, 2B, 3B, and 4B because the opening was the same. After the first four tests were completed, the XPS foam was cut larger to then accept and test specimens 1C, 2C, 3C, and 4C. The XPS foam was cut again to accept and largest test specimens 1A, 2A, 3A, and 4A.

Figure 4.2: Guarded hot box schematic [2].

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Figure 4.3: Specimen 1B in the hot box cold side on left and warm side on right.

Each test specimen was wired with type T thermocouples to determine if temperatures measured would match the predicted temperatures in the 2 dimensional models. 5.) Comparison of Results from Numerical Simulation and Testing 5.1 Comparison of Experimental and Numerically Obtained U-Factors The U-factors determined for each test sample are depicted in Table 1. Values indicated in the first row correspond to results obtained from numerical simulation; whereas, values shown in the second row were produced experimentally. In both cases, the U-factor provided corresponds to the total extent of the sample placed within the hot box chamber partition. For instance, with regard to test A which included vision glazed areas immediately above and below the spandrel area, the quantity indicated embodies the averaged U-factor of both the vision and spandrel components. Also included are the full extent of the frame and adjacent wood framing required to provide structural support for the sample in the chamber. Alternatively, U-Factors shown in the fourth row correspond only to the spandrel zone of each case determined numerically from the area spanning the center line dimensions of the vertical mullions and horizontal rails. The fact that these latter values were determined numerically deserves emphasis. Due to the inherent nature of the test it is not possible to distinguish the individual heat transfer contributions of each wall component to the overall rate of heat transfer. Instead, only the overall rate of heat transfer can be inferred from the entirety of the specimen. It serves to elucidate that the reason for including both results is to explore two different interests. Results corresponding to the entire sample provide a measure of accuracy of the test and allow for a direct comparison between numerical and experimental results. On the other hand, values corresponding only to the spandrel area show the effect of

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the different test assemblies selected on the value determined for the spandrel, which is of course the performance metric most pertinent to actual building performance. Assuming that the venerable ASTM standard provides a reliable benchmark for accuracy the quality of each simulation can be explored by observing the delta between the simulation results and corresponding experiments. To this aim, calculating the percentage of error for each case based on the quantities shown in Table 1, reveals that the agreement was at best 3% for case A4 and at worst 22% for case C1. Furthermore, calculating the average percent error corresponding to tests A, B & C yields respective values of -6%, 11% and 18%. These results show that the accuracy of the simulation does indeed depend on the physical configuration of the test sample (A-C) and insulation (1-4) chosen. Furthermore, they suggest that the level of error in the simulation increases with the actual R-value of the sample evaluated. This has been recently reported in non-shadowbox curtain wall spandrel cases. [8][9] Another metric by which the accuracy of the U-factors determined can be evaluated is gained by observing the equivalency criteria dictated by the NFRC 100 standard. The most recent version identifies that numerical modeling and test equivalency are established by the standard when the simulated U-factor is within 10% of the tested value and the simulated U-factor is greater than 1.7 W/m2K (0.3 Btu/hr-ft2-F). For cases with a simulated U-factor less than 1.7 (0.30) the simulation must be determined within 0.17 W/m2K (0.03 Btu/hr-ft2-F) of the test. Application of these requirements reveals that only cases B3, C1 and C3 would not be equivalent per the standard. With regard to the difference in performance determined between insulation treatments the percent improvement corresponding only to the spandrel area provides the most meaningful comparison. Please recall, that these values are obtained by simulation and must be regarded in light of the model accuracy discussed. For each case it is unsurprising that the maximum improvement over the baseline is obtained when insulation option 4, featuring the greatest thickness of vacuum insulation panel and carefully allocated aerogel blankets, is utilized. For tests A, B and C the respective percent improvements over the baseline were similar and on average a value of -18%. For option 2 which features a

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deeper shadow box recess than conventional insulation the improvement was closer to -4% for tests A & B and -7% for test C. With regard to option 3 there was no improvement and the values obtained were somewhat worse than the baseline case. 5.2 Temperature Measurements Clearly, U-factors and R-values are not the only simulation output that can be compared with experimental values. In fact, these aggregated quantities may be somewhat forgiving as an evaluation metric when compared to overall measurements since they possess the ability to conceal errors associated with local quantities. In order to account for this possibility and also to guide a forensic evaluation of differences between the numerical and experimental results local temperature measurements were also obtained at a vast number of locations throughout each sample. Namely, three effects were evaluated by temperature measurement: 1.) Accuracy of temperatures determined at frame locations 2.) Validity of the assumption of 1-dimensional heat transfer at the center of spandrel 3.) Verification of the absence or presence of longitudinal thermal gradients within finish panels and mullions Table 3 shows temperature measurements obtained at selected locations and compares each value to its counterpart determined by numerical simulation. Note that the deltas between experimental and numerical values are listed in every third column. A positive quantity indicates that the simulated value was warmer than the associated experimental value; whereas, a negative value indicates the opposite. At most the numerical value arrived at was ~9 F warmer than tested and at minimum it was ~12 F colder. For the most part the modeled values were colder than those tested and the majority of locations were within 6 F of the tested value. Figure 5.1 illustrates the placement of thermocouples within the spandrel assembly.In total, two traverses spanning each material layer from exterior to interior were taken. The location of the first traverse was situated at the exact center of the spandrel finish panel and the location of the second was taken at a quarter point as described in the figure. Specifically, a thermocouple was placed at the interface of each material so that the temperature distribution obtained by physical testing could be compared to values determined by simulation.

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Figure 5.2 shows all of the temperature results obtained within the insulation assembly corresponding to the baseline configuration (1) for each test assembly (A-C). Shown as a dashed line is the calculated result output from the 1-dimensional series resistance model that was used computationally for the test cases shown (A-C). The remaining curve parameters are linked with the experimental results obtained from tests (A-C). These results are reproduced in Figures 5.2, 5.3 and 5.4 respectively for the remaining insulation configurations (2-4).

Figure 5.3: Temperature Traverses Through the Spandrel Assembly Determined by Numerical Analysis and Testing for the Option 2 Configurations (Tests 2A, 2B & 2C) a Measured at Center of Spandrel Area, b Measured at Center of Quadrant of Spandrel Area Figure 5.1: Location of Thermocouples Placed Within the Spandrel Assembly

Figure 5.2: Temperature Traverses Through the Spandrel Assembly Determined by Numerical Analysis and Testing for the Baseline Configurations (Tests 1A, 1B & 1C) a Measured at Center of Spandrel Area, b Measured at Center of Quadrant of Spandrel Area

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Figure 5.4: Temperature Traverses Through the Spandrel Assembly Determined by Numerical Analysis and Testing for the Option 3 Configurations (Tests 3A, 3B & 3C) a Measured at Center of Spandrel Area, b Measured at Center of Quadrant of Spandrel Area

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Figure 5.5: Temperature Traverses Through the Spandrel Assembly Determined by Numerical Analysis and Testing for the Option 4 Configurations (Tests 4A, 4B & 4C) a Measured at Center of Spandrel Area, b Measured at Center of Quadrant of Spandrel Area

With regard to the present evaluation 4 thermocouples were placed strategically at 63.5mm (2.5 in) intervals perpendicular to the edge of the finish panel as photographed in Figure 4.1 for the purpose of detecting the presence of thermal gradients which may reveal heat transfer occurring from the mullion towards the center of the panel. Shown in Figure 5.6 are these measurements taken at the center of span of the sill for the baseline case. Since the plots obtained from the remaining cases show a similar trend they are not shown in the interest of compactness. It is readily observed from the figure that a gradient is apparent for each case; however, the slope is relatively similar amongst cases. This would suggest that thermal gradients within the finish panel alone cannot be the sole cause of the temperature differences observed at the center of spandrel. In fact, it is apparent from the figure that for each case there exists a temperature bias which permeates the entire extent of the panel, which is to say that the aggregate panel temperature is on average progressively higher for cases A & B than they are for case C.

Most noteworthy is the level of agreement achieved for each case as defined by the difference between experimental and numerical temperatures. There is a substantial contrast with regard to these outcomes. For the case of test C the agreement is relatively good; whereas, for cases B and A the agreement becomes progressively worse, and to a substantial degree. This result demands an evaluation of the differences between each test sample and the bearing of those differences on the validity of the 1-dimensional assumption made at the center of the insulation assembly. Sources of error which could be thought to give rise to the deviations shown in test cases B & A are most likely either associated with miscalculation of the resistance associated with each element, or are the result of significant heat transfer exchanges between zones allocated as thermal resistance elements. Errors in resistance may stem from improperly measured thermal conductivities, failure of frame cavity models to predict accurate effective conductivities or incorrect specification of film coefficients associated with natural convection and radiation. On the other hand, errors associated with heat transfer between elements may include unaccounted heat transfer pathways such as heat transfer exchange between the frame and center area through the finish panel or mullions. While not rigorously dismissible, the former option appears on the surface to be less plausible due to the fact that the agreement for test case C was good and also due to the fact that assumptions have been reliably used within the context of the existing standard for vision areas. Turning our attention to the latter possibility requires an intuitive forensic approach. It is the experience of the authors that insulating assemblies are often compromised very severely by conductive pathways which bypass the placement of insulation. To elucidate loosely with an analogy, an assortment of rocks placed randomly in a river will serve poorly as a dam. The fact that they are impermeable to water is only of merit when assembled in a contiguous fashion.

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Figure 5.6: Temperature Along the Leading Edge of the Finish Panel for the Baseline Configuration at the Sill Condition

Moving outward from the panel the next logical place to examine for the presence of unaccounted heat transfer pathways is within the frame components. In particular, at locations where lengthwise thermal gradients might be expected to occur as a result of insulation placement, the location of thermal breaks or as a result of the inherent geometry. In order to capture these potential outcomes thermocouples were placed along the lengthwise coordinate of each mullion at the transition from vision to spandrel as shown in Figure 5.1. Figure 5.7 shows the temperature gradient measured along the seam of the aluminum extrusion and bed gasket at the lower extent of the vertical mullion within the spandrel area. Unlike the previous case, there is a distinct difference in slope measured amongst the three test cases. It is important to recognize that the assembly for test A is dissimilar from cases B and C due to the fact that the vertical mullion passes from spandrel to vision at the sill of the unit. This provides some intuition regarding the steeper gradient observed for that case. With regard to tests B and C the vertical terminates at the jamb of the chamber and does not cross into the warmer zone.

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6.) Application of Modeling Approach to Typical Curtain Wall Assemblies In complement of the calculations reported by the test chamber testing and the numerical curtain wall model simulation, it is proposed to evaluate as Tier I how the different shadow box design configuration plugged as cassettes into a curtain wall are impacting the thermal transmittance performance of the facade sized to real scale dimensions.

Figure 5.7: Temperature Along the Vertical Mullion at the Transition from Vision to Spandrel Corresponding to the Baseline Configuration While these results are not exhaustive in resolving the deviation between center panel temperatures they do suggest strongly that the pathways for heat transfer exist that are not accounted for by the ISO 15099 standard. [10] To elucidate this point, the results shown are evidence that the resistance elements identified by the standard are not truly independent. This warrants a more detailed approach which should be the subject of continued research. A capability harnessed by modeling is the ability to show contour diagrams which illustrate the spatial variation of temperature and heat flux that would be very difficult, if not impossible to show experimentally. Figure 5.8 provides a handful of such cases corresponding to the jamb condition of each test. With regard to the temperature diagrams shown in the upper portion of the figure it serves to note that the more tightly the contours are spaced within a material the greater its resistance relative to other materials within the assembly. This is easily observable for the insulated regions of the test assembly. The tightly bound contours with the region of the vacuum insulation panel relative to the conventional insulation illustrate that even with reduced thickness enhanced R-values are achieved. The heat flux contour diagrams shown in the lower portion of the figure identify regions within the assembly where heat transfer rates are the greatest. Materials such as the galvanized back pan, finish panel and aluminum extrusions bypass the insulation to some degree as shown.

Figure 5.8: Color Contour Diagrams of Temperature and Heat Flux Corresponding to the Jamb Conditions of each Test

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A full “clear floor-to-ceiling vision glass” curtain wall of 77% against a “panelized vision glass” curtain wall of 38.5% Window-to-wall ratio will be compared against each other. Also, to get a better understanding of the energy efficiency benefits of the various testing configuration, a set of whole building energy simulation analysis across five US cities in different ASHRAE climates zones have been run as Tier II to measure and establish relative comparisons of their impact on the building energy use. Finally, the various spandrel configurations can achieve good aesthetical aspect while meeting performance. The outputs results are to be compared and discussed. Whole building simulations are run over an annual basis to compare their impact on the energy consumption of a fictitious simulated office building in 5 different climates zones (2A-Hot and Humid, 3C-Warm Marine, 4A-Mixed Humid, 5A-Cool Humid, 6A-Cold Humid associated respectively to the cities of Miami, San Francisco, New-York, Chicago, Minneapolis) as shown in Figure 6.1. This yields to a total of 40 energy simulation runs, running 2 different window-to-wall ratio facades for 4 different spandrel configurations in 5 climate zones. The weather files used are collected data sets of average hourly values over a 30 year periods of solar radiation and meteorological elements for a 1-year period intended to be used for computer simulations of solar energy conversion systems and building systems to facilitate performance comparisons of different building configurations. The energy model inputs set to the prototypical 15 stories high-rise office building are following the ASHRAE Standards 90.1-2007, Addendum G, Performance Rating Method[4] with the exception of the changing variables of façade thermal transmittance (U-Value) applied differently to the windows and wall area following the Therm[1] output values calculated. A detailed computer simulation using EnergyPlus Version 8.1.0.008 [11] coupled to the OpenStudio front-end interface was performed for a proposed office building design using an ASHRAE 90.1-2007 minimally compliant building parameters for the systems described in Tables 5 and 6 in the Appendix. EnergyPlus is a program that calculates an hour-byhour building energy consumption over an entire year of 8760 hours to simulate building energy consumption and cost using the typical meteorological weather data (TMY and TMY3) accessible from the Department of Energy (DOE) which has developed and supported the program.

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Figure 6.1: International Energy Conservation Code (IECC) ASHRAE Climate Zone

The calculations are not intended to provide any predictions of actual energy consumption or cost for the proposed design if the fictitious building was to be built. Actual experience will differ from these calculations due to variations of the weather pattern, the occupancy density and behavior, the building operation and maintenance. It is rather intended to show relative comparisons between the different cases. The following section summarizes the simulation parameters.

Figure 6.2: Averaged HVAC End-use Energy Reduction for 5 climates

The vertical fenestration area (total area of the fenestration measured using the rough opening and including the glazing and frame) above grade is distributed uniformly and in the same proportion across the four orientations.

Facade performance impact on HVAC Energy Consumption End-use (%) 70 350

[CELLRANGE]

300

6.1 Summary of Findings On average, across the 5 different cities it was found that cutting the Window-to-Wall ratio by 50% from 77% to 38.5% of glazing area had a significant impact on the overall faรงade performance improvement of the R-Value which increased by 37%. This yielded 6% reduction on overall end-uses and up to 11.3% energy use reduction as shown in Figure 6.2 on the HVAC end-uses variables loads directly impacted by the faรงade (Space Cooling, Heating, Pumps, Fans, Heat Rejection) and detailed in Figure 6.4. The relative energy use reduction of the building across the five climate is shown in Figure 6.3.

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[kBtu/sf/yr]

[CELLRANGE]

40 30

[CELLRANGE]

250 200 150

[CELLRANGE] [CELLRANGE]

100

[kWh/m /yr]

The simulated typical high-rise office building is intended to be 59.4m(195 ft) high made of 15 floors of 4m(13ft) high each with a width and length of respectively 30m x 30m (98 ft x 98 ft) with a central core of 10m (32 ft-10 ft) wide by 10m (32 ft-10 ft) long and a lease spend from the perimeter to the core depth of 10m (32 ft-10 ft) for a total area of 13,500m2 (145,260ft2) shown in Figure A1 in the Appendix. A typical floor of 900m2 (9,688ft2) is modeled with 4 symmetrical perimeter zones of 4.6m (15 ft), 4 interior zones and 1 central interior zone for the core and multiplied 13 times over the entire height of the building - using adiabatic settings on the floor slabs assuming no energy transfer in between each floor - excepting the ground and last floor exposed to unique boundary condition inducing different heat transfer mode when exposed to earth, solar radiation and wind.

0 Miami-2A

San Francisco-3C

New-York 4A

WWR 77%

Chicago-5A

Minneapolis-6A

WWR 38.5%

Figure 6.3: HVAC energy reduction per climate

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HVAC End-use break down - Energy Use reduction (%) - Average of 5 cities

20 [kBtu/sf/yr]

[CELLRANGE]

15 10

[CELLRANGE] [CELLRANGE]

[CELLRANGE]

Figure 6.4: Energy Use Reduction (%) – Average of 5 Cities

WWR 77% WWR 38.5%

[CELLRANGE] 0

0 Cooling

Heating

Pumps

Fans

One of the direct related benefits is the reduction of the energy bill on gas and electricity due to the reduction of the heat transfer rate across the assembly (heat gain and heat losses) and the immediate increase of opaque wall area acting as a mask against the diffuse and direct solar radiations enhancing the overall Solar to Heat Gain Coefficient (SHGC). but it can reduces as well the HVAC system size on the cooling tons, the fans, shafts and duct size dimensions needed to guaranty the interior user thermal comfort. Another beneficial aspect can be judged from a subjective visual standpoint. The frame layout being equally divided every 1.5m (5 ft) wide, in Figure 6.5, the addition of an opaque floor-to-ceiling insulated panel

110

[kWh/m /yr]

Cooling Towers

every other one, in Figure 6.6, allows a panelized checkerboard keeping a full clear vision glass area in between maximizing the daylight penetration into the space coming from the header and avoiding a significant continuous sill height of almost 1.47m (4’-9”) height casting the views when seating if the Windows-to-wall ratio had to meet the ASHRAE 90.1 2007 compliant path guidelines of 40% glazing area per paragraph 5.2.1.A of the ANSI/ASHRAE Energy Standard. The various spandrel configurations to test are detailed in Table 3 below and are associated to an energy run for each.

Figure 6.5: Rendering Option 1 (WWR: 77%)

Figure 6.6: Rendering Option 2 (WWR: 38.5%)

Figure 6.7: Option 1 (WWR: 77%)

Figure 6.8: Option 2 (WWR: 38.5%)

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Therm 2D Heat Transfer Simulation

Building Energy Simulations Runs Spandrel Configuration / Test 100mm (4”) mineral wool panel w/ 25mm (1”) mineral wool vertical mullion wraps 15.9mm (5/8”) VIP w/ 51mm (2”) mineral wool and 25mm (1”) mineral wool vertical mullion wraps 19mm (¾”) VIP w and 9.5mm (3/8”) aerogel vertical mullion wraps 29mm (1 – 5/32”) VIP w/ 19mm (¾”) aerogel vertical mullion wraps

SC1 SC2 SC3 SC4

OPT1 (WWR 77%) Run#1 Run#3

OPT2 (WWR 38.5%) Run#2 Run#4

Run#5 Run#7

Run#6 Run#8

Table 3: Spandrel configuration testing runs

The numerical model outputs from the Therm models for the U-Values of the Spandrel, Fenestration and overall assembly for Option 1 and Option 2 cases are shown above in Figure 6.7 and Figure 6.8 and compared against each other in term of performance improvement in Table 4 below. It is important to note the decrease of the performance of the Fenestration U-Value (Option 2) due to the absence of mullion wrap on the vertical jamb between the glazing and the panel yielding to a different design.

Testing options

Spandrel Configuration

OPT 1 (WWR 77%)

SC1

SC2 SC3 SC4 OPT 2 (WWR 38.5%)

SC1

SC2 SC3 SC4

U-Factor, [W/m2.K] [Btu/hr.ft2.°F]

R-Factor, [m2.K/W] [hr.ft2.°F/Btu]

Spandrel 0.806 (0.142)

Fenestration Overall 2.686 2.254 (0.473) (0.397)

Spandrel 1.2 (7.0)

Fenestration Overall 0.37 0.44 (2.1) (2.5)

0.772 (0.136) 0.852 (0.150) 0.664 (0.117) 0.721 (0.127)

2.686 (0.473) 2.680 (0.472) 2.686 (0.473) 3.168 (0.558)

2.243 (0.395) 2.260 (0.398) 2.215 (0.390) 1.663 (0.293)

1.3 (7.4) 1.2 (6.7) 1.5 (8.5) 1.4 (7.9)

0.37 (2.1) 0.37 (2.1) 0.37 (2.1) 0.32 (1.8)

0.44 (2.5) 0.44 (2.5) 0.46 (2.6) 0.60 (3.4)

0.681 (0.120) 0.767 (0.135) 0.585 (0.103)

3.168 (0.558) 3.146 (0.554) 3.168 (0.558)

1.635 (0.288) 1.680 (0.296) 1.578 (0.278)

1.5 (8.3) 1.3 (7.4) 1.7 (9.7)

0.32 (1.8) 0.32 (1.8) 0.32 (1.8)

0.61 (3.5) 0.60 (3.4) 0.63 (3.6)

R-Factor Improvement [%] Overall -

Shadow Box Depth [mm] [in] Spandrel 74 (2.9)

107 (4.2) 155 (6.1) 94 (3.7) 74 (2.9)

35.5%

37.2% 34.5% 40.3%

107 (4.2) 155 (6.1) 94 (3.7)

Table 4: Numerical model computed U-Factors

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Windows-to-wall ratio testing cases comparison - Energy Use reduction vs R-Value Performance per Cities

SC4

[CELLRANGE] [CELLRANGE]

41%

[CELLRANGE]

40%

[CELLRANGE] [CELLRANGE]

SC2 [CELLRANGE]

SC1

[CELLRANGE]

37%

[CELLRANGE]

36%

[CELLRANGE] [CELLRANGE] [CELLRANGE] [CELLRANGE] [CELLRANGE]

SC3 -18%

38%

[CELLRANGE]

R-Value Improvement

39%

35%

[CELLRANGE] 34%

-16%

-14%

-12%

-10%

-8%

-6%

-4%

-2%

HVAC Energy Use Reduction Miami

San Francisco

New-York

Minneapolis

Chicago

Figure 6.9: Façade performance improvement impact vs energy use reduction per Spandrel configuration

The Spandrel and Fenestration U-Value have been calculated using the Glazing Reference: Viracon VE-2M (VLT: 0.705 / SHGC 0.378). Across the different climate zones it can be observed a linear relationship between the relative comparisons of the ratio of the overall R-Factor of the façade performance associated to 77% window-to-wall ratio over the overall R-Factor of the façade performance associated to 38.5% windowto-wall ratio and the resulting overall HVAC energy use reduction, detailed in Figure 6.9. Higher R-Factor values yield to higher energy savings in a proportional way. The different depths of the shadow box mentioned above have been modeled in 3D and rendered using Vray v.2.40.03 and not intended to reproduce the visual reality. The images are put side to side for immediate comparisons below in Figures 6.10 – 6.13.

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Often times, achieving energy efficiency is directly associated to trade off with the old paradigm way of designing a building adding energy resiliency as has a new key variable to play with. The study conducted in this paper tends to show the opposite when balancing the energy performance with the external looking aspect of the facade. Compared to the SC1 baseline made of a traditional shadow box of 74mm (2.9 in) depth, the 3 other testing cases of deeper depths up to 155mm (6.1 in) for SC3 with a deep recess VIP panel, achieve an R assembly value almost all comparable, as shown in Figure 6.14. Designers have the option to play with different modules to expand their creativity through different composition without altering the overall performance of the façade.

Figure 6.10: Rendering of SC1 – Shadow box depth: 74mm(2.9”)

Figure 6.11: Rendering of SC2 Shadow box depth: 107mm(4.2”)

Figure 6.12: Rendering of SC3 Shadow box depth: 155mm (6.1”)

Figure 6.13: Rendering of SC4 Shadow box depth: 94mm (3.7”)

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Shadow Box Performance vs Depth Depth Shadow Box (mm) 50.8

76.2

101.6

127

152.4

177.8

1.8

1.6

1.4

1.2

7 6

0.8

0.6

0.4

0.2

SC1

0 0

SC1 SC2

SC3 5

R-Factor [m .K/W]

R-Factor [hr.ft .°F/Btu]

25.4

WWR 77% - Rassembly WWR 38.5% - Rassembly WWR 77% - Rs WWR 38.5% - Rs WWR 77% - Rfen WWR 38.5% - Rfen

0 7

Depth Shadow Box (in)

Figure 6.14: Shadow Box Performance vs Depth

Curtain walls being more and more expanded and largely utilized around the globe, from small to high-rise scale, Designers see the opportunity to explore new ways to enhance the expression of the building facades, customizing this epidermic layer in dialogue with the environment. The results show a range of flexibility to the architecture industry to achieve on average similar performance against traditional shadow depth associated to mineral wool insulation with deeper shadow box at the spandrel, increasing the perception of depth behind the glass and light penetration. This subjective approach becomes even more perceptible when the incident angle of sunlight during the day varies with the course of the sun, giving a different definition to the depth of the cavity, affecting colors, textures and contrast. At a wider scale this allows a customization of the façade to give a checkerboard effect. Where opacity being desired, a checkerboard panelized pattern can be achieved adding more subdivision to the curtain wall as suggested in Figure 6.15, improving even more the performance of the overall façade due to the reduction of the window-to-wall ratio.

Figure 6.15: Rendering of a Checkerboard façade looking aspect

Nowadays, building performance is consensus based and challenging, when the subjective qualitative looking aspect of a building needs to meet the objective quantitative energy performance aspect. The sweet point is at the crossroad of both and have to be balanced with each side of the equation. 7.) Conclusions The yearlong evaluation conducted and reported herein was a multidisciplinary effort across industries to benchmark the use of established standards for the purpose of evaluating the thermal performance characteristics of spandrel assemblies and furthermore to explore the performance potential of a novel insulating product. Included for this purpose was the design, analysis and testing of viable curtain wall assemblies to arrive at quantitative and qualitative results. 7.1 Quantification of the Performance of Vacuum Insulation Panels The performance of vacuum insulation as a building material should not be overshadowed as a result of what may be perceived by some as only moderate gains in overall envelope performance. Instead, they should inspire greater focus on the design of framing systems to harness the potential performance benefits of this insulating medium. In and of itself VIP is far more insulating than mineral wool insulation on an R-value per unit thickness basis. To illustrate this point, the effective thermal conductivity of a 25mm (1 in) thick VIP is equivalent to nearly 225mm (5 in) of conventional insulation. Subsequently it comes as little surprise that the test samples showing a minimal thickness were on par with the mineral wool sample in terms of their aggregate performance. This fact gives rise to aesthetic possibilities that were previously not possible as a result of the established practice. As discussed herein, the focus of future research will address the question of whether or not advanced framing system designs can harness greater

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thermal performance. This separate issue has a tantalizing appeal for those interested in achieving an advanced level of performance. What is known today as a result of this effort is that for conventional systems the limiting factor in performance is indeed heat loss through the frame. 7.2 Significance of Framing Effects To elucidate the previous point, the fact that heat loss through curtain wall framing has a significant impact on performance cannot be under emphasized. While this has been established to some degree by past efforts the magnitude of this impact is shown with a transparency of assumptions that has not formerly been presented. The results are devoid of any ambiguity which might contradict that: (a) the overall U-Factor of the spandrel area increases as the ratio of framing to spandrel insulation increases, (b) that the spandrel cavity temperature responds in an increasing manner, as evidence of a thermal bypass, with this ratio and that (c) the presence of any framing significantly detracts from the effective R-value of the insulation product used. Furthermore, temperature measurements taken throughout the sample establish that temperature gradients occur within the framing and spandrel finish panels. Such gradients support the presence of heat transfer in these materials. 7.3 Applicability of Accepted Industry Standards to the Evaluation of Spandrel In particular, it would appear that the NFRC 100 rating procedure is a prime candidate for adaptations that would allow it to be applied accurately as a mean to determine and certify the thermal performance of spandrel assemblies. Since this effort is ongoing and not reflected in the current standard it is not possible for the results obtained to confirm or disconfirm the potential fruition of this activity. At this time it is the knowledge of the authors that such efforts are being undertaken. If any utility is provided by the work presented here, it is to inform those involved of the limits of the modeling assumptions currently adopted for vision areas when they are applied to spandrel. The modeling approach reported was reasonably accurate within the equivalency requirements dictated by the standard. Of the 12 cases examined, only three failed to satisfy equivalency. While this fact is encouraging, it must be considered in accord with the observation that the samples chosen are not the same in terms of their dimensions as those currently specified by NFRC 100[3] for vision areas. In this study the dimensions of the spandrel zone were chosen to reflect those that are typical of actual buildings as they are understood by the industry professionals who participated. With regard to the construction of the test sample and the calculations performed it was established that termination of the horizontal framing at the head and sill of the unit had a significant effect on measured results even though the same framing details were used in both cases. Recall that for tests B and C adjacent vision areas above and below the spandrel assembly were not included as they were in case A. This owes to the fact that spandrel horizontals are very rarely symmetric intermediate details and often occur at transitions between vision and spandrel. If the full extent of the transition is not included in the test sample some fidelity will be lost.

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Perhaps the most significant outcome of the study was that the center of spandrel temperature distribution varied in a consistent way as a result of the dimensions and construction of the test sample chosen, a result which is reinforced by the fact that similar behavior was identified regardless of the insulation used. This may provide sufficient reason for pause amongst those who would champion proceeding with assumptions currently employed for vision, especially if further verification establishes that the center of spandrel performance is not independent of the adjacent framing. In so far as the temperature measurements that were performed are concerned, they serve to suggest that heat transfer through the interior finish panel and framing affect performance. 7.4 Application to Full Building Performance While the results surrounding the performance of spandrel areas as an indepedant entity are interesting in their own right it was the feeling of those who participated that they provide an incomplete picture of the role that spandrel performance plays in the overall picture of building energy performance. To this point, an effort was made to perform a case study based on a specific building. While it is implicit that construction and materials vary from the project to project the results provided should at least provide the reader with some level of intuition regarding the effect of relevant design variables. In the case of spandrel performance, the variation in R-value amongst the cases tested was not sufficient to show a significant difference in full building energy performance; however, this result is somewhat obvious in light of the findings that had already been presented. As could easily be infered from the foregoing, asthetic improvements leave more to harness from conventional assemblies than a performance improvement as a result of limitations that are imposed by heat loss through the framing. With regard to spandrel coverage, the results reinforce other studies which establish that inceasing spandrel areas has a favorable effect on overall building energy performance. Worthy of emphasis, is that for the present study all of the spandrel areas were unitized versus the alternative practice of hand setting such systems. With regard to systems affected by the envelope the improvments were as high as ~10% for a large increase in spandrel coverage. 7.5 Sustainability of Options The main objective of this study was to document the overall thermal performance impact of VIPs in comparison to that of current industry practice of using mineral wool insulation in non-vision areas. Through computer modeling and analysis, and further informed through physical testing, it has been shown that VIPs impart a positive thermal performance benefit to the façade system. However, like nature, building components and assemblies are only as good as the ‘sum of it’s parts’. The façade is but one of the many systems that make-up a building. In practicality, the facade is essentially the physical separation that controls the exterior elements from entering the built environment. Aesthetically, the facade is integral to expression of the design vision of the Architect. How does this relate to sustainability? This study relates to sustainability in the following ways. For modern architectural design, the goal is typically

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to achieve the highest percentage of vision glazing possible and to maximize daylighting, yet still optimize the thermal performance of the façade to meet the performance levels prescribed by building codes. The instinctive response to meet this challenge is to maximize the amount of thermal insulation in the non-vision areas of the façade. VIP helps to raise the thermal performance of the non-vision areas which in turn enable the Architect to maximize the vision glazing, whilst still maintain a comparatively slim facade profile. A similar approach can be applied to designs where the primary goal is to maximize the performance of the façade, which historically has resulted in facades with reduced vision areas to allow for controlled vision and daylight openings to favor thermal performance. Therefore, in addition to the direct thermal contributions to the façade, the VIP panels’ increased performance can allow additional vision glazing. This translates directly to additional daylight and heat gain in colder climates resulting in lower heating loads. In warmer climates, VIP spandrel panels will contribute in the reduction of heat gain through the increased R-value of the façade resulting in lower cooling loads. From a material perspective, the VIP panels are 100% recyclable[12] as such could serve to improve the carbon footprint of a building when factoring the longeity and service life. An Environmental Product Declaration (EPD) is available for interested parties to include the assessment of VIPs in a Life Cycle Analyis (LCA) as to its carbon footprint. 7.6 Design Implications Through this study of VIP as a replacement to the traditional mineral wool insulation it was established that the thermal resistance of the façade assembly could be increased by as much as 6%. The VIP through it’s higher thermal resistance also allows the Architect the opportunity more design freedom due to the reduced thickness required to achieve the same thermal performance as mineral fiber. It should be noted that the study looked at the code minimum panel which suggests that the potential for greater energy savings can be achieved if Architects challenged themselves to increase the non-vision areas on their façade designs to optimize the views and daylight in the building. It was learned the envelope thermal transmittance design variable was responsible for cutting 6% by itself of the total final energy when dealing with a typical office program internally load driven, but this parameter is only one step within an overall process to cut off energy consumption. The façade plays a buffer role with the immediate environmental exterior conditions but other conservative measures have to be considered to reduce energy consumption since once they are added together they yield to a meaningful asset. As mentioned above, aesthetically, the facade is integral to expression of the design vision of the Architect. The use of comparatively high performance insulation in the non-vision areas can serve to enable a

degree of design freedom to the architectural and design community – permitting designs to optimize vision glazing and daylighting opportunities, or conversely, balancing vision and non-vision components to maximize thermal performance properties. References 1. Therm 6.3 Lawrence Berkeley National Laboratory, http://windows.lbl. gov/software/therm/therm.html, viewed May 4th, 2015 2. ASTM C1363-2011 Standard Test Method for the Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus, West Conshohocken, PA: ASTM International 3. NFRC 100-2004 Procedure for Determining Fenestration U Factors, National Fenestration Rating Council Inc. 4. ASHRAE 90.1 2007. ANSI/ASHRAE Standard 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings, Atlanta GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc. 5. International Energy Conservation Code (IECC), International Code Council http://publicecodes.cyberregs.com/icod/iecc/2012/, ISBN 978-1-60983-058-8, viewed on May 4th, 2015 6. Binz, A., Moosmann, A., Steinke, G., Schonhardt, U., Fregnan, F., Simmler, H., Brunner, S., Ghazi, K., Bundi, R., Heinemann, U., Schwab, H., Cauberg, J.J. M., Tenpierik, M. J., Johannesson, G. A., Thorsell, T. I., Erb, M., and Nussbaumer, B. (2005). Vacuum Insulation in the Building Sector. Systems and Applications (Subtask B): IEA/ECBCS Annex 39 High Performance Thermal Insulation (HiPTI) 7. Mukhopadhyaya, P., National Research Council Canada “Long-term performance of Vacuum Insulation Panels (VIP) in the Canadian climate” Construction Innovation Volume 17, Number 3, September 2012 8. Carbary, L. D., Yee, S., Bagetelos, N., Architectural Insulation Modules: Thermal and Structural Performance for Use in Curtainwall Construction, ICBEST 2014 conference, Aachen Germany, June 2014 9. Norris, N., Carbary, L. D., Yee, S., Roppel, P., Ciantar, P., The Reality of Quantifying Curtain Wall Spandrel Thermal Performance: 2D, 3D and Hotbox Testing BEST4 Conference, National Institute of Building Science, Kansas City MO, 2015 10. ISO 15099 International Organization for Standardization. Thermal Performance of Windows, Doors and Shading Devices – Detailed Calculations, ISO/FDIS 15099, ISO TC163 11. Energy Plus, US Department of Energy, http://apps1.eere.energy. gov/buildings/energyplus/?utm_source=EnergyPlus&utm_ medium=redirect&utm_campaign=EnergyPlus%2Bredirect%2B1, viewed on May 4th, 2015 12. Dow Corning Environmental Product Declaration Vacuum Insulated Panels, ULE Declaration Number 13CA27308.101.1, http://www. dowcorning.com/content/publishedlit/Dow_Corning_Vacuum_ Insulation_Panels-EPD.pdf, viewed on May 4th, 2015

This article along with the article by Philip Wilson from Spatiale & Louis Moreau from Agnora are re-published by kind permission of the GPD team. They serve to prepare us for the forthcoming 25th Anniversary of the wonderful Glass Processing Days event that takes place in Tampere, the birthplace of world class glass conferences in June 2017 - I know you’ll be there

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See the possibilities Innovations in glass and glass manufacturing for a sustainable future by Paul Anderson Architectural SpeciďŹ cations Manager Guardian Glass

Markthal in Rotterdam: MVRDV Architects - product: Guardian SunGuard SN 70/41

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While the aesthetic properties of glass will always be important, sustainability is not only increasingly important, it is critical to our future. Therefore, as we continually innovate to make products that help improve our quality of life, we also need to look at all aspects of production and performance if we want to get the full picture on the challenges of sustainability. Contemporary architecture is notable for its generous use of glass. More and more glass is being integrated into building designs, increasing the amount of natural light in our buildings. This plays an important role in our quality of life: shops are brighter, offices more efficient and our homes feel more spacious. Light provides a sense of well-being and helps us embrace our personal and professional environments. The properties of glass make it, literally, an attractive option for architects. For starters, its aesthetic appeal makes it pleasing to external onlookers as well as a building’s occupants. Today’s increasingly advanced glass products also can help in improving people’s comfort and lowering their energy bills. Architects appreciate the sustainability features of glass because they are always looking for ways to help reduce the environmental impact of their buildings. Using glass with a high thermal index for the windows in a room can significantly reduce the room’s energy requirements, both in winter and in summer. Looking to the future The changing needs of society show us that to secure the long-term future of architectural glass, we must look beyond the demands and expectations of today. We need to constantly evaluate how glass is used and how it enables interaction with our surroundings. We need to see all the possibilities.

Architects today can build increasingly larger glass façades because glass is far more flexible and efficient than ever before. This is mainly thanks to improved coatings. Advanced coating technology enables high performance solutions that offer an optimal balance of properties to suit any location and situation. For instance, high performance glass can provide both solar control and thermal insulation. Innovation: increasing product value Thanks to our process of continuous improvement, Guardian Glass is making glass more energy efficient to produce. We are not holding back on product innovation either! Guardian Glass invests tremendous resources on improving glass performance in g-value, U-value, and other efficiency measures such as clarity, durability, safety and more. For example, our SunGuard® Solar Control Glass has a coating which transmits substantial amounts of daylight while minimising solar heat transmission as much as possible. And as we constantly drive product performance, flexibility and application range grow, especially in the commercial construction segment. Along with improvements in glass performance, Guardian has also developed glass solutions that meet the aesthetics of the project. By combining flexibility, colour and function, these products support architects as they set out to realise their visions, while at the same time meeting the needs of owners and users.

Sustainability in action The 100,000-square-metre, arched Markthal, or Market Hall, in Rotterdam, the Netherlands, represents a stunning example of the beauty and sustainability of glass. Designed by the Dutch architectural firm MVRDV, the structure’s exterior incorporates 10,000 square metres of Guardian SunGuard® SuperNeutral® 70/41 and Guardian ExtraClear® glass in the apartment windows as well as elsewhere in the building. Winner of the 2016 prestigious Rotterdam Architecture Award, the Markthal has been designed to provide a fully integrated, sustainable combination of food, leisure, living and parking. The award recognises buildings which ‘highlight the cohesion of the urban fabric and the liveliness of the city’.

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Clerkenwell Turnmill London: Architect Piercy & Company – Photographer Jack Hobhouse – product: Guardian SunGuard SN51/28

At the recent Glasstec show, Guardian Glass introduced a range of new Guardian SunGuard® products that offer enhanced aesthetics at all angles. The SNX 60 Ultra, SN 70 Ultra and HD Diamond 66 Ultra coatings have been optimised for use on Guardian UltraClear™, a low-iron float glass which is clearer and more colour neutral than standard float glass. The use of UltraClear float glass delivers maximum transparency and colour neutrality without the green tint of standard float glass. The result is the perfect solution to meet the current trend for colour-neutral glass facades while still offering high light transmission and excellent thermal performance.

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Satisfying building energy codes To produce solar control glass, Guardian uses a Magnetron Sputter Vapor Deposition (MSVD) process. By using various gasses, such as argon or nitrogen and oxygen, and by depositing layers of metallic and dielectric materials in different sequences, we can produce a wide variety of coatings to meet a wide variety of requirements. In this way, we offer a range of products that can achieve dramatic energy savings, meeting or exceeding local and regional building energy codes, yet satisfying different aesthetic and design requirements.

Energy efﬁciency: from products to production It’s quite easy to see – and feel – the improvements in glass performance, but is glass production also following suit? For example, the production process of float glass involves

running a furnace at 1,600 °C around the clock, 365 days a year. This not only consumes lots of energy, the nature of the process means that heat inevitably escapes the furnace. Industry players are taking decisive steps to address this waste heat and improve efficiency. Guardian intelligent glass solutions

Case Studies Glass has implemented a customised Waste Heat Recovery System (WHRS) at its UK glass manufacturing plant in East Yorkshire. The WHRS utilizes an ingenious process to capture waste heat from the furnace, without disrupting the delicate convection currents critical for molten glass formation. The WHRS represents a new approach both for Guardian and for the glass industry. By turning the captured heat back into energy, it provides half the electrical energy needed to operate our full float line. This in turn reduces dependency

on the grid and effectively reduces CO2 emissions. So now our energy-efficient coated glass products are made in a more energyefficient production plant boasting a smaller carbon footprint. Material wealth: responsible sourcing Another aspect of sustainability and environmental responsibility relates to materials sourcing. Here too, Guardian continues to invest. Recently, after independent assessment by the British Standards Institution, our Goole, UK production facility gained BES 6001

Waste Heat Recovery System

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30 Cannon Street: Delvendahl Martin Architects & Arup â&#x20AC;&#x201C; product: Guardian SunGuard SN 62/34

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accreditation from the Building Research Establishment (BRE), for its responsible sourcing of materials. The BES 6001 certification assesses how well companies operate within strict standards of supply chain management and environmental and social responsibility when managing relationships with suppliers. Specifically, it acknowledges the ‘Responsible Sourcing of Construction Products’. It requires an organisation to demonstrate good management of transport impacts, greenhouse gas emissions, and the impact on employment and the local community. Moreover, the holder must show that the company engages with its own supply-chain partners to deliver sustainable policies of their own.

Standards collaboration Guardian has been following the development of the BES 6001 standard closely for many years. We have been working with British Glass and BRE – the authors of the standard – to help them better understand the glass and glazing industry and how the standard could be applied to address this construction product in the supply chain.

Conclusion Glass has always been a tremendous asset to society and as long as products evolve to meet new challenges, its value in the future is clear. Of course, as well as its performance, we must consider its production. By investing in new technologies and using few resources, we can reduce waste in our processes, explore better utilisation of existing assets and continue to expand our knowledge of glass applications. At the same time, giving architects, occupants and observers the freedom to enjoy the amazing aesthetic values of glass. And we need to understand that when it comes to finding more sustainable solutions, glass may well be a significant part of the solution.

Innovation brings new opportunities Innovation is also driving improved aesthetics in modern architecture. Glass may be fundamentally clear, but the perfect view and transparency are often adversely affected by glare, reflection, or filtering of the original colours. Continuous investment in improved processes and innovative coatings enables solutions, like Guardian Clarity™ anti-reflective glass, that helps achieve higher light transmission and lower reflection for better views. They also increase the versatility of glass, allowing more, as well as more adventurous, architectural opportunities. See what’s possible with Guardian Clarity on http://www.sunguardglass. eu/Products/AdvancedSolutions/ GuardianClarity/

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T hCea sI G e SS tcuodl ui emsn o f P a u l B a s t i a n e n

This World is on ďŹ re!!

The IGS Column of Paul Bastianen

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T h e I G S c o l u m n o f PCaausle BSatsutdi ai en se n

The Olympic Games of 2016 are far behind us, and oh boy, what exciting games they were! It began with scandals about the extensive doping affairs of Russian athletes, where positive doping samples were concealed from a high national level. This scandal prevented a significant number of Russian athletes from competing in the games; unfinished Stadiums and dubious accommodation for theOlympian athletes; some sporting competitions took place in the middle of the night when Europeans were still fast asleep, BUT, we all watched and greatly enjoyed the various sporting battles that ensued. The Olympic Games temporarily diverted us from events that dominated conversations and set Europe, and indeed the entire world on fire - BREXIT. Then of course there’s the devastating war in Syria, the terrorist attacks in Europe, the military coup in Turkey, the refugee crisis in Europe, the elections in USA, need I go on? Transitions are a kind of social transformation that spans throughout the time of a generation. Every transition is formed in four stages: stage 1 is the development phase from a dynamic equilibrium to eventually becoming established as the status quo (a disruptive technology). Stage 2 is ignition, in which the changes are emerging and settling into place; Stage 3 is the acceleration phase in which structural changes take place; And Stage 4 is the stabilization phase in which the rate of change decreases as the new system or technology has completely usurped the old, and becomes the norm, the accepted standard. These changes are not always conveniently progressive, for instance when we moved from coal to gas, which led to a transition in energy management, this was not a foregone conclusion. Let’s turn our attention to two quotes: ‘’History is the mother of truth, it bear witness to the past and serves as an example and advisor to the present’’ said Miguel de Cervantes, a noted Spanish writer. And secondly, “If you want the present to be different than the past, study the past”, a quotefrom Dutch philosopher Baruch Spinoza. Both are philosophical and clearly true. Looking at the last two centuries, there were three major transitions: the first industrial revolution between 1780 and 1850 which transformed a small scale handicraft concern into a fully mechanized production. The second industrial revolution occurred over roughly 60

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years from 1870 to 1930, that featured further mechanization in the assembly lines and the deplacement of iron to steel. The third industrial revolution started in the 1940’s and is now about to end. The development of computers in which the United States and Japan have played leading roles is the foundation of the third revolution and has clearly now reached saturation and the degradation phase. The strongest companies have been able to compete and/or take over competitors, big eats small if you please. Revolutions originate through ideas, inventions and discoveries, or by newly accumulated knowledge and insight. The world is currently facing the same problems it did at the end of the second

industrial revolution with similar symptoms of declining stock market indices, a steep rise in unemployment, the towering debt of companies and Governments, and the poor financial position of banks. There are currently few new inventions or discoveries that will help us reach the next industrial revolution, the chance to achieve this in the short term is uncertain. With tensions between the United States and Russia, the war in Syria, emergence of IS and the changes of NATO countries such as Turkey. The world’s economy is in a similar situation to the way things were during the second world war (1940-1945). It is now time for world economies and cross border industries to decide upon the most appropriate transition to be deployed.

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How will the next industrial revolution be defined? Smart technology continues to develop. Data and algorithms make decisions that formerly were taken by people. The results are not only based on reliable predictions, forecasts and a positive impact on our health, but also traffic safety and efficiency in factories. It is predicted that by 2020 humans will no longer be operating production lines, by 2025, factories will also fear for their survival because 3D printer can take it all away, 50 percent of todays products are 3D printed. China, the “Mother of the manufacturing industry” would be in a panic if it was asked to pay back all it’s debts to the West. The concept of 2025 takes something from the past. We don’t just want music, we want a stream via Spotify. We do not want a hotel, we want a pleasant setting and the option is for Airbnb,

which is growing in popularity and now realizing a million bookings a day. If they carry on in this vein within 5 years Airbnb will be larger than the Hilton group. Within the next 5 years, new medical devices will allow us to monitor our own health. In 2025 medical family practices will be replaced by smart devices that are connected to a super doctor Watson of IBM who will take care and warn us of any potential health problems. Skills that were perfected and used for the last 30 years will be of little or no use within 5 years.

The phenomena of skills training will take on a different perspective as lifelong learning becomes the motto. Many jobs for which we are now trained will simply no longer exist. Companies, institutions and Governments need to organize themselves in a different way. A new form of management is needed, a “disruptive management”. A new criteria is needed as demands on work, power and results will need a different type of organisation, a different corporate culture, different networks are required alongside employees with a different mindset than the one we have today. According to the Trend Watcher-Futurist and the keynote international speaker Richard van Hooijdonk, the following groundbreaking trends are emerging one by one in different sectors such as health, agriculture, transportation, logistics, retail, construction and education : • • • • • • •

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Big data Robotics 3D printing Drones Virtual reality Biotech Nanotech

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The IGS column of Paul Bastianen

• Energy • Media • Privacy hacking 1. Big data will give us a better picture of how we can use our time more effectively or how we can keep track on the state of our health. By 2020, we will have five times more data than we have now; this information is submitted by technology. In previous IGS columns I made reference to Industry 4.0 and I tried to explain that the integration of information exchange will help glass industry production to follow individualized specification with 3D printing in special design. 2. Robotics provide endless possibilities and we will meet them in the future everywhere: in the army, in medicine, in office administration, or energy production. Industrial robots now support many companies worldwide. Think of welding, painting, assemblage, ‘ pick & place ‘ and product inspection. Even the car producer Tesla manufactures cars in a factory where there are no humans. Industrial robots are more durable, more precise, faster and cheaper than the ‘old fashioned’ human based production. Artificial intelligence is going to help us with the assignment of unique human skills in machines. The glass industry must undertake Industry 4.0 methodology together with window and facade producers and fabricators in how best to utilise robotics and animation in the industry. This is already happening on a small scale in some segments of the industry e.g, PVC window frames, but there’s no movement in the glass processing industry....still. 3. New business models will appear. With the advances in 3-D printing I am thinking of subscriptions or leasing or of a specific ‘pay-as you go‘ (pay–per use) models that are very popular in certain areas like iTunes. Printers appear on the market that provides this raw material to niche markets such as health or agriculture. We can print at extremely low cost everywhere and everything. In my previous IGS columns I wrote about a 3D printing in construction, which changed a design possibilities enormously. 4. Drones provide a solution for a wide variety of challenges that were impossible to solve in the past. Smart drones are equipped with cameras and sensors and are linked with other systems. So we see drones flying over the

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agricultural field, which followed by an analysis and prediction can immediately give a forecast of the harvest to the farmer. In addition, drones are excellent for special tasks like inspection, deliveries, photography and film. Drones that are associated with smart cities, will in future be able to give shots of the area after a robbery or other such criminal activity. Police algorithms can then scan for suspicious movements and people. This is happening now. 5. Since the dawn of civilization “physical strength” has always been a property that could at least guarantee our survival. This was defined over years but in future, intelligence will rule. Virtual Reality has honed our mental adroitness, our movement and speed are much more dependent on our intelligence. In 2016, we see that Virtual Reality and Augmented Reality technologies are useful in other ways than in gaming. 6. Biotechnology is still a relatively new field, but it has fantastic potential when it comes to the promotion of medical developments. Many advances arise from developments in personalized medicine, in which patients new treatment methods are applied depending on particular circumstances and if disposable can be used appropriately according to genetic factors and other specific medical characteristics. Biotechnology is already being applied to fruits and vegetables to change colours, flavours and shapes. I have recently seen pioneering surgical operations on dogs

where biotechnology was used to aid the recovery of the animal. 7. Nanoscience and nanotechnology are 21st century credits and include the study and application of extremely small particles. The technology can be applied in different areas, such as in chemistry, biology, physics, materials science and engineering. This technology has been known in the glass industry for years and is now widely applied in nano-thick coatings for all kinds of applications. It is enough to look in to heat and solar control insulating glass, with magnetron coatings. New technologies to be developed in this area in the future should tackle the issues of preservation which makes the facade more durable, with lower maintenance costs and suitable for different geographical environments. This includes both hot and cold climates. This is important as the outcome is already under BREEAM certification and has to be seriously taken into account. 8. The future of energy offers great opportunities. Think of solar energy, wireless energy, electricity and energy that we gain from the air. We are continuously looking for new energy sources, maybe we will find it in space. There are several ways in which we obtain and use energy but this will change and it starts with smart grids: Smart thermostats and roads that enable our cars and self-driving vehicles to be‘’wirelessly-charged’’. SBSP (space-based solar power) generates energy via satellite for us to use here on Earth. Solar panels in space are

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The IGS column of Paul Bastianen

expected to be about ten times more efficient because they can focus on the Sun 24 hours a day. A ‘Smart Grid ‘ is an energy delivery system that has evolved from a central management system as we know it today, to an intelligence system that continuously adapts and refines the supply of energy. Energy surpluses from different user points (factories, hospitals, homes) are re-distributed to points where there is the possibility of energy shortage. All this is running within a system in which sensors, big data and algorithms of different energy sources and users are clinked together. The ‘Smart Grid ‘ will save us billions in the future. 9. Media has been strongly influenced by technology and this will happen in the future on an ever larger scale. The Internet of Things, gadgets, smartphones, virtual reality can all be used by global media news, articles, videos and all other kinds of information they would like to share. Communication in the coming years will be completely different to the way we communicate today. Thus we can get smart kitchens with VoIP and cameras, so that we can make contact with others and through our refrigerators we can order new groceries. We will soon be digital in every aspect of our life: car dashboards, our smart watches, they can be considered as the new smartphones! 10. We are increasingly concerned about the threat to our privacy, personal freedom and autonomy, by companies or Governments. Even by private individuals. Every week there are new facts coming forward, showing that we have less and less confidence for the organisations who have our personal information. The Internet of Things (IoT) makes daily life easier and more efficient but also more worrying. Planes are already connected to the tourist office and include a contact with satellites. A hacker has shown that he could change the satellite data of an airplane so the plane could be sent on an alernative route. The device that he needed, costs less than a thousand euros.

Private house in Hattem, Netherlands

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Large factories, such as energy and nuclear power plants, can be a target. In 2010 a nuclear plant was shut down by a cyber attack. Another cyber attack caused an explosion in a German steel mill. In Japan there were almost 1300 cyber attacks in 2014, an increase of 200% compared to the previous year. Big producers such as Siemens and General Electric are scratching behind their ears as to how they

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The IGS column of Paul Bastianen

can secure many of their valuable connected data and systems. They have not yet found an answer. In 2020, over 50 million devices will be connected, the terrorists of the future will love it as a simple hack will bring forth catastrophe. We face a huge challenge and it goes throughout the entire chain, from the architect, to the builder to suppliers such as the glass industry. Is the glass industry ready for the new industrial revolution which currently is already on the drawing board of the architect? I refer once again to my previous IGS columns where itâ&#x20AC;&#x2122;s been stated that the glass industry needs to step up the pace, it has been moving far too slow for far too long. Paul Bastianen

Emporia shopping centre Sweden

If you would like to comment on this column or on other topics, I would be pleased to hear from you by phone +31 643 888 728 or email p.bastianen@planet.nl

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Case Studies

AUTHORS DETAILS

Main Header Miriam White Clyde Dixon Land & Property 51 Park Road Kingston Upon Thames London KT2 6DB United Kingdom Tel: +44 (0) 7736 232577 E-Mail: miriammimiwhite@gmail.com

Klaus Lother Managing Director Josef-Gartner GmbH Gartnerstrasse 20 89423 Gundelfingen Germany Tel: +49 (0) 9073 840 www.josef-gartner.permasteelisagroup.com

Valérie Hayez Dow Corning Parc Industriel de Seneffe 7180 Seneffe Balgium Tel: +32 6488 8000 www.dowcorning.com E-Mail: Valerie.hayez@dowcorning.com

E-Mail: Klaus.lother@josef-gartner.de Dr. Helen Sanders Sage Electrochromics,Inc Sage Glass Saint-Gobain 2 Sage Way Faribault, MN 55021 USA Tel: +1 (0) 507 331 4848 www.sageglass.com E-Mail: hsanders@sage-ec.com

Standﬁrst

Joachim Stoss Edgetech Europe GmbH Gladbacher Strasse 23 52525 Heinsberg Germany Tel: +49 (0) 2452 9649 10 www.de.quanex.com E-Mail: j.stoss@edgetech-europe.com Guus Boekhoudt Vice-President Bodycopy Guardian Glass Europe Zone Industrielle Wolser L-3452 Dudelange Luxembourg Tel: +352 (0) 52 1111 www.guardianglass.com E-Mail: gboekhoudt@guardian.com Agnes Koltay Guillermo Fernandez Koltay Façades PO Box 215476; Office R-101-A Podium Villa R Executive Towers, Business Bay Dubai UAE Tel: +971 (0)4 425 3593 www.koltayfacades.com E-Mail: agnes.koltay@koltayfacades.com guillermo.fernandez@koltayfacades.com

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Lisa Rammig Eckersley O’Callaghan Engineers 236 Gray’s Inn Road London WC1X 8HB United Kingdom Tel: +44 (0) 207 354 5402 www.eckersleyocallaghan.com E-Mail: lisa@eckersleyocallaghan.com Zaha Hadid Architects 10, Bowling Green Lane London EC1R 0BQ Tel: +44 (0)207 253 5147 www.zaha-hadid.com E-Mail: info@zaha-hadid.com Jutta Albus Johannes Pellkofer Universit t Stuttgart Institut Für Baukonstruktion IBK2 Germany Tel: +49 (0) 711 685 83996 www.uni-stuttgart.de E-Mail: jutta.albus@ibk2.uni-stuttgart.de Johannes.pellkofer@ibk2.uni-stuttgart.de Dr Andreas Wolf Dow Corning Parc Industriel de Seneffe Rue Jules Bordet 7180 Seneffe Belgium Tel: +32 6488 8000 www.dowcorning.com E-Mail: andreas.wolf@dowcorning.com Kuraray/ Trosifol Mülheimer Strasse 26 53840 Troisdorf Germany Tel: +49 (0)22 412550 www.kuraray.com E-Mail: trosifol@kuraray.com

Philip Wilson Spatiale S.A.R.L 14 rue Oberkamf 75011 Paris France Tel: + 33 (0) 1 49 29 76 26 www.spatiale.com E-Mail: info@spatiale.com Louis Moreau Agnora ( Architectural Glass of North America) 200 Mountain Road Collingwood, ON Canada Tel: +1 (705) 444 6654 www.agnora.com E-Mail: info@agnora.com Lawrence Carberry Dow Corning Corp. Corporate Centre Midland, MI 48686-0994 USA Tel: + 1 (0) 989 496 4400 www.dowcorning.com E-Mail: Lawrence.carberry@dowcorning.com

Paul J Anderson Guardian Glass UK Tom Pudding Way, Goole East Riding of Yorkshire DN14 8GA United Kingdom Tel: +44 (0)208 366 1662 www.guardianglass.co.uk E-Mail: panderson@guardian.com Paul Bastianen PBH Publications Damloper 69 NL-4902CE Oosterhout The Netherlands Tel: +31(0) 643 888 728 E-Mail: p.bastianen@planet.nl

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