DETAIL Green English Edition November 2014

Solar WorldDecathlon exhibition 2012 of emerging in Madrid architecture: the Solar Decathlon Qualitätsmanagement Less is more – or is it? On fürsuffi gesunde ciencyInnenräume in building Vorschau Resource-effi aufcient die EnEV steel2012 composite construction

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∂Green 02/14 DETAIL Special Edition 66266 ISSN 1868-3843

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Magazine World exhibition of emerging architecture: the Solar Decathlon 2014 in Versailles Jakob Schoof

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Projects

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Events

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Publications

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Background Less is more – or is it? On sufficiency in building Jakob Schoof

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Sustainable architecture Students’ centre in London O’Donnell + Tuomey Architects, Dublin

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Office building in Woking Hopkins Architects, London

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Residential building in Hamburg architekturagentur, Stuttgart

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Education complex in Hamburg bof architects, Hamburg

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Research and practice Building design with a vision: experimental houses in Nyborg Jakob Schoof

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Resource-efficient steel-composite construction in office buildings Richard Stroetmann, Christine Podgorski

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Products and materials

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Planning partners and manufacturers

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Editorial and publishing data/photo credits

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www.detail.de/english Publishers and editorial department: Institut für internationale Architektur-Dokumentation GmbH & Co. KG, Hackerbrücke 6, 80335 Munich, Germany, Editorial department: Christian Schittich (editor-in-chief), Jakob Schoof E-mail: redaktion@detail.de, telephone: +49 89 38 16 20-57; Advertising: e-mail: anzeigen@detail.de; telephone: +49 89 38 16 20-48; Distribution & subscriptions: e-mail: detailabo@vertriebsunion.de; telephone: +49 61 23 92 38-211 UK correspondent: Oliver Lowenstein Translations: Sharon Heidenreich, Lance Phipps, Feargal Doyle, Sean McLaughlin English copy-editing & proofreading: Anna Roos

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Content/Editorial

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A common grievance among architects, in particular, is that sustainable building has become the domain of technical experts who conceive of buildings as power plants rather than places where people live and work. This tendency is being reinforced by excessive legal requirements that result in buildings which are highly complex, but dysfunctional in actual practice.

Furthermore, these requirements run contrary to the principles of ‘good design’.

This is not entirely incorrect. But, those who merely complain implicitly demonstrate their powerlessness. It is therefore encouraging that, in many spheres, there are signs of a counter-movement and buildings are being created that fulfil the criteria of both sustainability and good design. Here, architecture is key. First comes the design concept and then, subordinate to it, the technical planning.

Space and the designed structure, rather than pipes and equipment, are the most important means of ensuring energy efficiency in these buildings. Moreover, they often display a new simplicity that is not based on complicated construction as minimalism used to be, but rather on the genuine endeavour to achieve more with less.

In the current issue of DETAIL Green, we present a series of buildings that illustrate this economy of means. We begin with the houses at Solar Decathlon 2014, which were not simply conceived as plus-energy, single-family homes as in the preceding competitions, but as solutions to urgent social and urban-planning problems in the home countries of their designers.

We continue with the discussion about sufficiency in building, whereby architects can make a name for themselves as pioneers of a new ‘less is more’ approach. The issue also features a research project in Nyborg in Denmark that tackled questions of sustainability above and beyond pure efficiency. In the case of new buildings in London, Hamburg and Woking, which are looked at in this issue, planning was not primarily aimed at technical innovations, but at the skilful combination of tried-and-tested solutions.

In order to avoid any misunderstandings, it should be noted that these buildings are often complex – especially in spatial terms – and have yet to prove their viability. What’s more, the idea is not to renounce all the technical achievements of the past few years. The aim is to help bring about a reappraisal of a vital resource that not even masses of technical equipment can adequately substitute: namely, human intelligence. It is, and will remain, an indispensable component of sustainable building design – irrespective of high-tech materials and simulation programmes.

Jakob Schoof

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2014 ¥ 2 ∂Green

World exhibition of emerging architecture: the Solar Decathlon 2014 in Versailles Jakob Schoof

Italy in first place, followed by France and the Netherlands, and then Germany and Switzerland – these were the results of the Solar Decathlon Europe 2014, decided in mid-July in Versailles, near Paris. It was a neck-on-neck competition in which Team ‘RhOME’ from Università degli Studi Roma Tre, squeezed ahead of their competitors from Nantes and Delft, on the final day, by the slimmest of margins, a mere 0.88 points.

It would not do the exhibition justice, however, to judge it solely on points scored or values measured. Like a magnifying glass, the Solar Decathlon reveals current trends and technological developments in the field of sustainable building. Furthermore, in Versailles, important decisions were revealed, which will impact the future of one of the most prestigious student architectural competition worldwide.

Despite receiving great media interest in recent years, the Solar Decathlon nonetheless has provided hardly any new answers to critical questions for the future.

Prior to Versailles, the rules of the competition had not been altered since the competition’s inception in Washington in 2002.

The brief stipulated that each team should design and finance a house for two occupants with a floor area of 45 to 75 m2. The

designs are ultimately erected at the exhibition site where their performance is monitored over a two-week period. The projects are evaluated in ten different categories, seven of which are assessed by juries, and three of which are evaluated through continuous monitoring by sensors installed in each room. Each house has to operate self sufficiently using solar energy − in so far as this is possible under the climatic conditions at the competition site – and, despite the small floor area, should offer all the comforts that one would expect from any other house.

Concepts for the city of tomorrow Inevitably this prescriptive framework led to certain similarities between the projects. Moreover, and more crucially, single-family homes are certainly not the building typology that is most suited to solve the myriad of urban, social and ecological problems of the world. In order to better address this problem, the organisers in Versailles decided to change a few of the rules. They requested that the projects focus on important issues relevant to the future of architecture; such as urban density, cost effective building, the integration of architecture and mobility, and the efficient use of resources and energy.

But above all, the designs should propose solutions to conditions in the home countries of the respective teams.

The design teams took on the challenge with analytical focus and a wealth of interesting ideas. A little abstract thinking was required to understand some of the concepts, as − due to scale, cost and time factors − the projects presented in Versailles in the form of single-family homes, were usually only prototype sections of far wider-reaching concepts.

The winning entry from Rome makes a proposal for a social housing block in timber construction, which − if an investor can be found − could someday be the first of its kind to appear on the outskirts of the Italian capital.

The team that was awarded second place presented a concept to revitalise an early modern industrial building in the port of Nantes with a combination of residential accommodation and greenhouses. TU Delft even reconstructed the entire terraced house of the grandparents of one team member at the competition site, which they used to demonstrate their concept for an energy-saving renovation using solar energy. Five of the teams − including the Berlin team that came in fourth place − simultaneously presented Team

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1. Rome (IT) 2. Nantes (FR) 3. Delft (NL) 4. Berlin (DE) 5. Lucerne (CH) 6. Valparaiso (CL)/La Rochelle (FR) 7. Frankfurt (DE) 8. Lyngby (DK) 9. Angers (FR)/Boone (USA) 10. Sant Cugat (ES) 11. Chiba (JP) 12. Hsinchu (TW) 13. Mexico City (MEX) 14. Rhode Island (USA)/Erfurt (DE) 15. Alcala/Castilla − La Mancha (ES) 16. Cartago (CRI) 17. Bangkok (TH) 18. Mumbai (IN) 19. Bucharest (RO) 20. Paris (FR)

Score 840,63 839,75 837,87 823,42 804,75 802,42 793,71 780,01 776,92 776,24 774,09 772,15 760,17 657,46 650,44 588,80 508,15 452,30 348,49 268,81

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Rooftop structure for a typical old Berlin apartment building: Rooftop (TU Berlin/UdK Berlin) Overview of the competition area with the Palace of Versailles in the background above the trees Renovation of a Dutch terraced house: Prêt−à− loger (TU Delft) Symbiosis of living and horticulture: Philéas (Team Atlantic Challenge, Nantes)

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houses which were actually conceived as rooftop extensions for existing buildings.

Many entries that did not feature amongst the frontrunners also presented thoughtprovoking ideas. The students from Chile and Japan concentrated on reconstruction after floods or earthquakes, whilst their colleagues from Mexico City designed a low-cost building system for residents of slums and shantytowns, which focus on the particular climate and chronic water shortages of the Mexican capital.

Affordability was a priority for the southern European teams. The students from Sant Cugat near Barcelona − winners in the category ‘Architecture’ − presented the simplest of buildings with a scaffolding structure and polycarbonate envelope, which was donated after the competition to a community in the Catalonian hinterland. How the building is used can be decided by the community itself: the building layout is so flexible that it functions equally well as a community hall, a supermarket or a workshop.

The designs of three of the teams demonstrated the potential of international cooperation. Amongst them was the terraced house ‘Maison Reciprocity’, in which students from Angers (France) and Boone (USA) sought to promote the use of Euro-

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pean solid timber construction in North America. In this case, the journey that the building materials took is characteristic of the early phase of such a technology transfer (albeit with high transport costs): the cross-laminated timber slabs for exterior walls, floors and roof were manufactured in Austria, further processed in the college in the USA into finished building elements, and then returned to Europe for the competition.

Sustainability beyond the energy issue In Versailles, the fact that the Solar Decathlon − as its name indicates − is centred on the use of solar energy became almost incidental. Urban planning, design features and social aspects were consistently the focus of the presentations. Some important themes for the future kept reoccurring; for example the use of recycled materials, which has become almost standard, particularly in the interiors of Solar Decathlon houses. In general, the quality of workmanship that many teams displayed in the interior fit-out of their buildings would be worthy of its own evaluation category in the future. The furniture and interior fittings were often designed by students from the same colleges.

A second, constantly recurring trend was

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urban gardening or horticulture. It was the Nantes team who pushed this theme the furthest by covering the entire flat roof of the former industrial building with green houses, which they envisage being managed by professional horticultural companies. In other houses, residents were invited to act as (hobby) gardeners themselves, to maintain either large planting troughs, green facades with automatic watering or − significantly cheaper − earth-filled plastic drink bottles cut in half.

A further future theme was: the ‘Sharing Economy’. The communal use of space and resources was the primary concern of the ‘Your+’ house, from Luzern. The project represented a section from a larger residential building complex, in which the living space per person would be 35 square meters, rather than the current standard in Switzerland of 50. This would be achieved via a differentiated hierarchy of private rooms and bathrooms, kitchens used by small groups, and living areas and other spaces used by all residents of the building.

Break out into the smart grid When it comes to energy supply concepts, the Solar Decathlon 2014 represents a paradigm shift, which can already

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Projects

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Boomerang effect Office building in Pantin Fassio Viaud Architectes, Paris

Ground floor plan Scale 1:1000

Pantin is a town with 50,000 inhabitants just beyond Paris’ ring road, the Boulevard Périphérique, to the northeast of the city. Directly in the town centre, amidst a heterogeneous environment consisting of a major thoroughfare, the town hall, a school and the Canal de l’Ourcq stands this 6250 m2 office building designed by Fassio Viaud Architectes, which is largely run by energy generated on-site. The overall form and layout of the floor plans were determined by the boomerangshaped site, which slopes to the south.

The previous use of the site as a car park was retained and incorporated into the lower ground floor of the new-build. The four office floors thus seem to be suspended one level above the ground, and are separated from the street by a strip of

glazing. According to the architects, this had several beneficial effects, both in terms of costs (further excavations were not needed for an underground car park) and, in terms of user satisfaction, as notoriously unpopular ground-level workspaces could be avoided altogether.

The building – which was funded by an investor – can accommodate a total of 466 office workers, and be divided up into as many as eight separate rental units.

To preserve flexibility in the interior layout, the facades of the building consist of load-bearing concrete with 18 cm of insulation and rainscreen cladding made of white Corian panels. According to the architects, this is only the second time that this mineral compound material has been used as a facade cladding in

France. The architects justify this rather costly solution with the longevity, seamless aesthetic and self-cleaning effect of the material, which allows graffiti to be easily removed.

The new-build complies with the French ‘Bepos-effinergie Standard’, which means that its primary energy demand for heating, cooling, ventilation, fixed lighting, and hot water amounts to a mere 40 kWh/m2a of primary energy, and is offset by the energy generated by a 700 m2, 144 kWp photovoltaic array on the roof. Furthermore, just as a boomerang – if skilfully thrown – will always return to the person who threw it, a large part of this electricity is actually used within the building (e. g. for elevators, IT and office lighting) rather than fed into the grid. To maximise this proportion, a fleet of electric cars (which are made available to employees) is incorporated into the system, with their batteries being recharged mainly when excess electricity is available.

Heat is supplied to the offices by a groundwater heat pump via ceiling panels, which at the same time accommodate the lighting and act as sound attenuators.

For cooling purposes, the groundwater (at 12 °C) can flow directly through the same ceiling panels. All of these measures result in utility bills being about 60 % lower than those of average office buildings in the neighbourhood. The energy concept did not stop with the handover of the building either: During the first three years of operation, the users will receive advice from a specialised environmental consultancy on how to optimise their energy consumption behaviour.

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November 2014 International Passive House Days Passive house residents open their homes 7.11.2014 – 9.11.2014 Worldwide www.passivehouse-international.org/ index.php?page_id=262 RIFF Architecture Conference Conference on architecture and habitat 10.11.2014 − 11.11.2014 Bucharest/Romania www.ieriff.ro BIG 5 Dubai Largest construction trade fair in the Arab Gulf Region 17.11.2014 – 20.11.2014 Dubai/UAE www.thebig5.ae RENEXPO South East Europe Trade fair and congress on renewable energy and energy-efficiency 19.11.2014 − 21.11.2014 Bucharest/Romania www.renexpo-bucharest.com Passi’bat French Passive House Congress and trade fair 25.11.2014 – 27.11.2014 Paris /France www.passibat.fr NZEB and Beyond Symposium Symposium on energy-efficient architecture, nearly zero energy buildings and energy-efficiency refurbishments 27.11.2014 Brussels/Belgium www.nzeb.be/en 2nd Passivhaus Portugal Conference Congress on energy-efficient architecture 29.11.2014 Aveiro/Portugal www.passivhaus.pt

December 2014 20th Internationales Holzbau-Forum International congress and exhibition on timber construction 3.12.2014 – 5.12.2014 Garmisch-Partenkirchen/Germany www.forum-holzbau.com TIM Expo Shanghai Trade fair on thermal insulation materials and energy-efficient technologies 5.12.2014 – 6.12.2014 Shanghai/China www.baowenzhan.com.cn/en/

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PLEA 2014 30th international PLEA conference; theme: Sustainable Habitat for Developing Societies 16.12.2014 − 18.12.2014 Ahmedabad/India www.plea2014.in

January 2015 BAU 2015 International trade fair for architecture, materials and systems 19.1.2015 – 24.1.2015 Munich/Germany www.bau-muenchen.com Klimahouse 2015 International fair on energy-efficient construction and sustainable building 29.1.2015 – 1.2.2015 Bolzano/Italy www.klimahouse.it

February 2015 MiaGreen 2015 Expo & Conference Trade fair on green building, solar energy, clean technology etc.

Miami/USA 11.2.2015 – 12.2.2015 www.miagreen.com 1st South Pacific Passive House Conference Conference and trade show on passive house design and technology 15.2.2015 – 16.2.2015 Auckland/New Zealand www.passivehouse.org.nz/ World Sustainable Energy Days Congress on sustainable energy production and use in construction, industry and transport 25.2.2015 – 27.2.2015 Wels /Austria www.wsed.at

March 2015 EcoBuild Trade fair for sustainable design, construction and the built environment 3.3.2015 – 5.3.2015 London/UK www.ecobuild.co.uk

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ISH 2015 International trade fair for bathroom design, energy and air-conditioning technology as well as renewable energies 10.3.2015 – 14.3.2015 Frankfurt/Germany ish.messefrankfurt.com Expo Build China 2015 International trade event for the construction industry 30.3.2015 – 2.4.2015 Shanghai /China www.expobuild.com

April 2015 5th Forum Bois Construction (FBC) Congress and exhibition on timber construction 16.4.2015 – 17.4.2015 Nancy, France www.forum-holzbau.com 20th International Passive House Conference International congress and trade fair on energy-efficient buildings 17.4.2015 – 18.4.2015 Leipzig/Germany www.passivhaustagung.de

May 2015 4th Forum Internazionale dell’Edilizia in Legno Congress and exhibition on timber construction May 2015 Verona/Italy www.forum-holzbau.com

CEB Clean Energy Building Trade fair for renewable energies and passive housing 20.5.2015 – 22.5.2015 Stuttgart/Germany www.cep-expo.de

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2014 ¥ 2 ∂Green

Less is more – or is it?

On sufficiency in building Jakob Schoof

‘Reduce Reuse Recycle’ was the slogan of the German pavilion at the Architecture Biennial 2012. The exhibition was a powerful plea against the feverish new building boom and in favour of the creative appropriation of existing built structures. However, the need to ‘reduce’ – i.e. to actually decrease specific types of construction activity – only played a marginal role in the event. This was hardly surprising. After all, neither architects, construction companies, or the German Government – who financed the German pavilion at the biennial – are interested in the continual reduction of building activity in Germany.

Nevertheless, the question “How much is enough?” has become a hotly discussed topic in architecture – at least in parts of Central Europe. Two years ago, Zurich’s Building Surveyor’s Office published a first basic draft for an “Energy Sufficiency Roadmap” [1], and in the meantime, there have been congresses dedicated to this issue.

The discussion relating to sufficiency – i.e. moderate consumption – in the area of building development fits in well with the ongoing debate in society on the question: how much (economic) growth our ecosphere can actually tolerate? And this is by no means something new. As early as 1973, the American economist, Herman E. Daly, published his book Steady-State Economics. In the publication, he calls for a rejection of continuous economic growth, which he argued, our planet would not be able to

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cope with in the long term. E. F. Schumacher made similar critical remarks against continual growth in his book, Small is Beautiful, as did Dennis Meadows et al. in the seminal first report to the Club of Rome, Limits to Growth.

In the following years, criticism of growth decreased, the widespread hope being that technical progress and efficiency improvements would gradually decouple economic growth from the consumption of natural resources. However, this only happened in a few exceptional cases. Seen from a global point of view, the current situation looks dismal; for example, worldwide CO2 emissions have risen by as much as 40 % since the beginning of the 1990s.

An effective, but unpopular approach In ecological theory, sufficiency is regarded as being the third component of effective sustainability strategies. The first two of these are efficiency (which tries to achieve more with less resources) and consistency (which strives towards closed cycles of materials and the use of renewable energy, i.e. a mode of industrial production that is consistent with the cycle of materials in nature). In practice, however, it is disputed whether sufficient lifestyles can ever become attractive to the population at large.

At the same time, the wasteful manner in which we erect and use our buildings and city districts are strikingly obvious. For example, the heating demand of Germany’s residential building stock has decreased by around 1.8 % per year since 2005 (Fig. 3). Most of these efficiency gains, however, have been consumed by the increase in the amount of living space per capita.

As a consequence, the consumption of heating energy per person has remained almost static. In Switzerland (and other European countries), the situation is no different. Moreover, targets have only been achieved with respect to heating energy; the consumption of electrical energy in households is still increasing steadily – in Switzerland, for example, by 15 % in the last decade.

Another known dilemma relates to the heating behaviour of building occupants. Whereas heating systems in the 19th century were designed for a room temperature of 16 °C, it was already 18 °C at the beginning of the 20th century and, in the post-war period, quickly rose to about 20 °C. Today, most people heat their homes to a temperature of 22–23 °C. This rebound effect is mainly apparent in the efforts to improve the energy performance of buildings. If an average old building is insulated, the real energy saving is frequently 20–30 % lower than the saving previously calculated. In buildings that were extremely inefficient prior to renovation, this figure can be as high as 50 %. The main reason being that, after renovation, occupants tend to heat their rooms considerably more than before.

The list could be continued with the growth in size of our cities in terms of the area they cover. In the EU, an area the size of Berlin

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Prototype of a student residence in Versailles (F), Technical University of Darmstadt 2014. The size of the individual rooms is limited to 7.2 m2 each.

To compensate for this, the residents dispose of a generous (but only partially heated) communal space.

Residential and commercial building in Zurich (CH), Müller Sigrist Architects 2014. The amount of living space has been reduced to 35 m2 per capita.

Development of the space heating demand and living space per capita in Germany. For most of the last 5 decades, the increase in living space has (over-)compensated for any improvements in energy efficiency in buildings.

Typical CO2 emissions per capita, per year depending on type of building, living space per capita and user behaviour (according to [1])). Also indicated is the target value for the Swiss 2000-Watt society. The graph shows that ambitious climate targets can only be met by a combination of energy-efficient buildings (refurbishment or new build), limited living space per capita and modest user behaviour.

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In its study, Zurich’s Building Surveyor’s Office demonstrates how much energy could be saved if buildings were equipped less lavishly and users behaved more ‘sufficiently’. For example, a widely known rule-of-thumb states that one degree less room temperature results in a 6 % saving in heating energy. However, this figure only applies to inefficient old buildings – in an average new building, it is more like 10 % and, in a passive house, over 13%. This shows that sufficiency, i.e. using only what is strictly required, is particularly important where the potential for efficiency improvements has largely been exhausted.

Reducing the amount of living space by a third results in a saving of around 15% with respect to the energy use in a building, the reason being that not all areas of consumption (e.g. hot water and power consumption) decrease proportionally to the living space. All in all, the biggest differences in consumption between a life-style that is moderately sufficient (but by no means ascetic) and one that is wasteful occur in the field of electricity use (Fig. 7). With regard to heating, the percentage differences tend to be limited, but the differences in absolute terms (above all in

old buildings) should not be underestimated, as heating accounts for the largest portion of the overall energy consumption.

Fig. 7 shows the cumulative differences due to differences in home size, home equipment/fittings and user behaviour. Yet, changes in behaviour alone can also have a considerable impact. Pilot projects in which tenants were given advice on energy consumption and then changed their behaviour have shown that 20–25% energy savings can be achieved in the area of heating, between 18% and 30% in the case of hot water, and 20–50% with respect to power consumption (lighting and electrical equipment) without the building, itself, having to be altered.

Pilot projects relating to sufficiency As with consumption, the same question also arises regarding the restriction of energy use: How much is enough? Most people will probably not want to go as far as the Munich-based architecture professor, Richard Horden, who in 2005 designed an experimental student housing estate consisting of ‘micro compact homes’ 6.5 m2 in size – he even inhabited one of the micro units himself for a period of several years (Fig. 9). Nevertheless, there is currently a trend towards having tiny apartments for students and young people who are just starting their careers, especially in large cities with high property prices. These dwelling units are usually around 20 m2 in size and offer all the amenities of modern city living. What is interesting is that there are hardly any such options for single people who are older. This suggests that the older people become, the more living space they want or need – especially once they retire from work and spend most of their time at home.

Nonetheless, it is possible to devise modestly-sized housing for all age groups., The building ‘Kalkbreite’ was completed in the summer of 2014 in Zurich (Fig. 2). It houses a tram depot, a cinema, shops and restaurants, as well as 88 apartments – all unGWP [kg CO2 eq./Person]

is still being claimed every year for new settlement areas and transport routes – and this at a time when the size of the population is almost stagnant.

Even in the area of building construction, there is unused potential for the improvement of sufficiency. Continually increasing demands for noise and fire protection, as well as modern amenities are causing buildings to become ever-more complex with the number and extent of technical installations in them steadily increasing. For example, a luxury shower unit with integrated loudspeakers and automatically controlled lighting may sound impressive – but its embodied energy exceeds that of a 20-yearold model several times over.

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Less is more – or is it? On sufficiency in building

2014 ¥ 2 ∂Green

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der one roof. The building (which complies with the Swiss Minergie-P-Eco Standard) not only meets the highest energy-efficiency requirements and complies with ecological methods of construction, but also includes two sufficiency components. On the one hand, all occupants have to agree to abstain from owning a car for the rental duration, and on the other, the living space is limited to 35 square meters per person. The latter restriction is, without doubt, a helpful measure in order to keep the rents affordable in the exorbitant Zurich area. However, this also shows that the client is serious about the goals of the ‘2000-Watt Society’, which has officially applied to all new buildings in Zurich since a referendum in 2008. The 2000-watt concept envisages a limited energy budget per person that must suffice for all areas of life (housing, mobility and private consumption). This limit is easier to adhere to in 35 m2 of living space than in the almost 50 m2, which is otherwise typical in Switzerland.

‘Sufficient’ user behaviour is becoming more and more relevant where buildings are intended to achieve the Zero or Plus Energy Standard, and not only in theoretical calculations, but also in reality. A so-called ‘active townhouse’ with 74 apartments is being erected on a site in Frankfurt’s inner city. Photovoltaic modules on the roof and on the southern facade are intended to generate more power than its occupants need, including household electricity (Fig. 5). To achieve this, their active participation in energy saving is required. To this end, each apartment contains an integrated PC tablet. The latter displays energy consumption and generation in real time, estimates the future energy yield of the photovoltaic equipment (based on weather forecasts) and gives the occupants specific tips on how to save energy (Fig. 6).

What’s more, there is a financial incentive; each household has an annual energy budget (not particularly generous, but adequate if the occupants are economical) that is included in the all-inclusive rent. Only if consumption exceeds the budget are households individually charged for the additional kilowatthours.

When buildings are being constructed, there is also a certain amount of sufficiency potential that can be exploited – especially if intelligent design replaces expenditure on materials. In its new office building, called ‘2226’ in Vorarlberg, the architecture office, be baumschlager eberle decided to omit any kind of heating, cooling, or ventilation system (Fig. 8). For heating purposes, only the heat gains from people, IT equipment and solar are Sufficient

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used; whilst cooling and ventilation are achieved by means of automatically controlled flaps alongside the windows. In the Woodcube, a residential building in Hamburg (see. p. 36), the client and architects refrained from the use of additional plasterboard panelling on the solid wooden walls and ceilings. This would normally have been necessary for fire-protection reasons.

However, extensive fire protection tests in the laboratory were first necessary in order to convince the authorities that the construction was actually fireproof.

What both these examples have in common is the large amount of expensive planning work required. In the case of the Woodcube, this has resulted in high rents, whereas for ‘2226’, the architects mostly worked ‘pro bono’. Such buildings will therefore only be economically efficient in the future if the experience gained in this context becomes widely known and can be used for planning and standardisation.

Political leeway If moderate approaches to building are to become more widely adopted, it is necessary to progress beyond just a few pilot projects; the process should also be supported politically. To this end, the authors of the Zurich Energy Sufficiency Roadmap are absolutely correct: “Sufficiency cannot be prescribed. But it can be promoted to a certain extent, for example by means of occupancy regulations for individual residential estates, refraining from the provision of parking spaces for individual estates, incentive taxes and so on.”

Such an incentivising effect could be achieved, for example, if legal energy standards were to be staggered according to the amount of living space needed per person. A generously sized, single-family house would then have to consume considerably less energy per square metre than a compact multi-apartment dwelling. The regulations governing fees for planners also contain disincentives that could be eliminated. To the regret of many people (including, most notably, clients), the rule so far has been that the larger, more complex and therefore more expensive a building is, the higher the fees are for the architects and engineers. However, anyone who strives to bring about reforms in this regard will have to introduce new, transparent and unambiguous benchmarks to replace the previous orientation to construction costs. And this will undoubtedly be difficult.

For really effective sufficiency incentives, a recognised fact from the area of environmental economics is decisive: anyone who aims to reduce resource consumption must make it more expensive. In principle, the way to do this is to impose eco taxes or to integrate private households into the EU-wide emissions trading scheme. However, neither of these two measures is likely to be popular with the public. There is another reason why most politicians shy away from implementing really effective measures; they realise that if everyone were to exercise sufficiency, the

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Residential building in Frankfurt (D), HHS Architects + Planners: With real-time feedback on energy generation and consumption, the designers aim to motivate the building users to be modest energy consumers.

Screenshot of operation panel with indication of the monthly energy use and the weather forecast Differences in energy consumption between moderately sufficient and ‘wasteful’ households Office building in Lustenau (A), be baumschlager eberle. Due to an intelligent building management system, there is no need for active heating or cooling in this building.

Student residences in Munich (D), Horden Cherry Lee Architects with Haack & Höpfner Architects 2005: On a mere 6,5-m2 footprint, these cubes contain all the amenities needed for modern student living.

[1] Zurich’s Building Surveyor’s Office (pub.): Grundlagen zu einem Suffizienzpfad Energie, Zurich 2012. Available for download at www.stadt-zuerich.ch/nachhaltiges-bauen >Fachinformationen [2] Jukka Heinonen: The Impacts of Urban Structure and the Related Consumption Patterns on the Carbon Emissions of an Average Consumer. Doctoral thesis, Alvar Aalto University Helsinki 2012, accessible at http://lib.tkk.fi/Diss/ 8

economy would stagnate and there would be a threat of social conflict relating to the re-distribution of wealth.

It can therefore be expected that sufficiency will only continue being negotiated on the level of individual life-styles, and anyone who wants to advance it will have to rely on personal conviction, exemplary pilot projects and optimally attractive incentives.

What is important here is the realisation that only a combination of efficiency, consistency and sufficiency will make it possible to achieve ambitious sustainability goals such as those of the 2000 Watt Society (Fig. 4). In old, inefficient buildings, moderate behaviour alone is of little help, and two people sharing a 200-square-metre passive house will also miss the target by far.

Moreover, the influence of the built environment on our ecological footprint should not be overestimated. The Finnish architect, Jukka Heinonen, for example, used his dissertation to clear up a few myths about the supposedly energy-efficient mode of living in compactly built-up cities [2]. Heinonen compared the CO2 footprint of a typical inhabitant of Helsinki with that of an average Finnish person living in the countryside. He found that, apart from commuter traffic by car, the city dweller emitted more CO2 than a person living in the countryside in all (!) areas of life (i.e. goods consumption, air travel, dining out, power consumption and even space heating). The results cannot be applied 1:1 to other countries – in Finland, for example, there is a huge differ-

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ence in affluence between the city and the countryside, and CO2-neutral heating with wood is preferred in many rural homes.

These issues are nevertheless food for thought.

An opportunity for architects?

This could actually be the end of the matter. Sufficiency is primarily a concern of the life-style of individuals and would remain a niche issue in architecture for the foreseeable future if it were not for the fact that ever-greater numbers of people are compelled to live ‘sufficiently’ in the world’s expensive cities as they can’t afford not to. Soaring real estate prices are already causing the living space per person in many places to decline again, rather than to rise. In particularly extreme cities, such as Tokyo, it has never even reached the European level. This is precisely where architects are called upon to design housing for a sufficient, yet nevertheless comfortable way of living. Intelligently conceived floor plans, high quality fixtures and fittings, generous communal areas outside the home and other spaces (e.g. bedrooms for guests) that are shared with others rather than individually owned, enable a high standard of living even in a limited amount of space. The planning processes are also important in that, although intensive participation of the users may sometimes be annoying for architects, it does enhance occupants’ identification with the final product.

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Office building in Woking Eco-Tech revisited Oliver Lowenstein

Of the four main practices associated with the British ‘high-tech’ movement in the 1990s, it has been Michael Hopkins Architects whose architectural identity has been perceived as moving furthest from that initial characterisation. While Richard Rogers, Nicholas Grimshaw and, most obviously, Norman Foster have maintained many aspects of high-tech architecture in their work, transforming briefly into ‘eco-tech’ at the turn of the century, Hopkins started to explore more traditional materials such as brick and timber, and has engaged with the tactile and atmospheric properties that these materials can create. Still, in any Hopkins building where these materials have been employed, high-tech structural solutions, expressed in elegant minimal detailing, are a constant. The recent World Wildlife Fund’s Living Planet headquarters in Woking, on the southwestern edge of London’s sprawling suburbs, is no exception.

The 92m-long, low slung, sleek office building is the latest in a

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series of Hopkins’s timber-hybrids, which have long been part of the practice’s sustainability profile. These include Yale University’s School of Forestry and Environmental Studies, Kroon Hall, which was awarded LEED Platinum rating in the US in 2009, and the Olympics Velodrome, a project that became the landmark building of London’s 2012 Games. The latter, in particular was a highlight for the studio, showcasing how the integration of timber into their palette has been used to refine, broaden and indeed redefine Hopkins’s previous high-tech approach.

The new World Wildlife Fund’s UK headquarters is the latest expression of this fusion, featuring a lightweight engineered timber-hybrid diagrid roof. The building responds to a brief set by the client for an office building to promote both their work and the business case of an ambitious, low energy workspace agenda. As one of the first BREEAM Outstanding rated mixed-use buildings (it has been certified according to a BREEAM 2008

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Client: WWF UK, Woking Architects: Hopkins Architects, London Structural engineers: Expedition Engineering, London Environmental design consultants: Atelier Ten, Glasgow Life cycle asessment: Sturgis Carbon Profiling, London Landscape architects: Grant Associates, Bath General contractor: Willmott Dixon Construction, Letchworth Garden City 2

building at any one time, with an extra 30 spaces for hire, as well as breakout and other spaces. This version was then taken up in the next design stage. Obviating the need to accommodate one third of the staff significantly reduced the building’s potential size. A smaller building meant less emissions and, of course, less expense. Project architect, Mike Taylor highlights this reduction as a “key point”, arguing that smaller optimised buildings are greener, and that this is an ‘ethical’ approach designers need to take into consideration. About 35 %, or 10,000 square feet, was carved away from the original size of the building.

The smaller footprint also reflects changes in work and communications organisation, with WWF-UK embracing the hot-desking revolution. Cisco Technologies, along with a number of other tech firms, which had already collaborated on the London Olympics (an event that had likewise been informed by an One Planet Living approach), worked with WWF-UK in moving towards a ful-

Bespoke scheme), the 3,600 m2 structure cuts energy use by just over 50 %, compared to an average building of the same size and use. The total project cost amounted to £20 million, including a £5 million donation from the Rufford Foundation.

Early on in the design process, WWF-UK had visited Hopkins’s London office, and found the showcase mix of lightweight and high-tech architecture appealing, particularly the dismountable mezzanine which part of the studio operates in. This prospective increase of work space also slotted in well with the site, a car park on land owned by the town council, a short distance from the centre of Woking. The result is an elongated, cleanly resolved building, raised above the still existing car park, amidst considerable foliage, and flanked on one side by a road and on the other by the Basingstoke Canal.

Alongside targeting the highest possible BREEAM rating, the design team assembled by Hopkins also committed to using and promoting the One Planet Living approach developed by BioRegional with the WWF. It is not surprising, therefore that the design team consists of a number of increasingly influential offices that have recently been in increasing demand in the UK for their environmental expertise. Expedition Engineers are respected structural engineers, who worked with Hopkins on the Olympics cable net structure, while Atelier Ten have built a formidable reputation for low energy building services that started in the early 1990s.

Strategies for reducing carbon For WWF-UK staff, the contrast with their old working quarters is considerable, and dramatically illustrated by the open diagrid roof canopy. Where previously the organisation had worked in cramped, separated rooms in a series of older buildings in nearby Godalming, their new work environment is spacious and airy.

From the main lower floor, sizeable windows overlook leafy trees that provide shade and natural cooling in summer.

At each end of the HQ, landscaped gardens continue this verdant surrounding, while inside, a row of potted trees take pride of place on the lower ground floor. The interior layout is a result of work early on in the five-year project, when carbon analyst consultants, Sturgis Carbon Profiling established that although there were around 350 staff members, at any one time there were actually only between 200 (40 %) and 250 (60 %) staff in the Godalming offices. The remainder were absent, working either at home, or on projects around the world. Sturgis prepared three initial research scenarios: light, mild and dark. The last scenario highlighted a building with a total capacity of 300 staff, accommodating a reduced WWF-UK staff of 230 working in the 1 2 3

Southwest view of the building with car park beneath Site plan Scale 1:5000 Breakout area at the southwestern end of the building

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Office building in Woking

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Lightweight timber shells and the green office of the future The diagrid canopy, comprised of engineered glulam sections, and supported by steel struts along both sides, is the most immediately visually appealing, tactile and structural feature of the building. It also complements both WWF’s lobbying activities in terms of forestry certification, and provides the environmental organisation with the striking example of a contemporary open plan office that it had set out to create together with the Hopkins team. At first, back in 2008, a timber deck was by no means assured. Material variations included steel, concrete, and a wide range of timber structures, including gridshells, other doublecurved shell structures, as well as straight timber and even solid timber roofs. After a few design variations however, timber – which had been the most appealing option from the onset – also became economically justifiable. The required, low curved shape of the roof, while too low for an effective barrel-vaulted arch, also ruled out the more complex, time consuming and expensive design which either a gridshell or lamella would have involved. This made the simple, regular diagrid an obvious structural solution. The result is an exposed glulam single-span canopy, which curves over the upper mezzanine floor, rather close to those working below, at a height of 6.5 metres. The smooth, regular, 37.5-metre diamond lattice spans the entire workspace, each side sloping down gently to the building’s edges. Comprised of long, thick glulam beams, joined by steel connectors, the structure invokes a sense of mathematical regularity and consistency.

Handled by Constructional Timber, the deck went up in 16 weeks during the autumn and early winter of 2012/13. In all, there are 828 individual glulam trusses, or 214 m3 of glulam, weighing 98.5 tonnes, manufactured by the Austrian company, Kaufmann. Where the upper mezzanine meets the sloping glulam beams, thin metal tubes have been added to the diagrid for Area

Baseline Final (after Stage C) (as built)

Embodied carbon emissions

t CO2 eq.

t CO2 eq.

Roof Building services Lift Internal fit-out Facades Sanitary (WC, shower, kitchen) Structure External works PV array Site preparation and excavation

1,170 2,310 200 2,880 1,630 210 2,480 1,010 670 540

700 1,920 140 1,210 680 160 1,230 850 410 210

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1,010 2,400

1,010 2,400

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extra load-bearing support. Outside, along the building’s external edges, long V-struts transfer the loads of the roof into the concrete substructure.

Outside the building, a canal bridge and ramp to the entrance foyer provide a fine view of the building as one approaches.

From here, another signature element of the building comes into view: a series of roof cowls that assist the exhaust ventilation in summer. They can be seen as more orthodox variations of the kind that pepper ex-Hopkins employee, Bill Dunster’s BedZED, and a few early Hopkins’s buildings.

A new form of eco-tech?

It is difficult not to admire this elegant building, which in different surroundings might, externally at least, be mistaken for a particularly chic railway station canopy, or airport hangar. Still, the effort that went into attaining the cherished BREEAM ‘Outstanding’ rating (which was, in turn, was a significant element in ensuring that the project met One Planet Living Standards), shows how challenging it will be to make One Planet building culture a norm, rather than languishing in the realm of showcases.

At the same time, the successful delivery of the building also invokes a new form of eco-tech – one in which the emphasis is shifted from hi-tech materials to the hi-tech modelling of materials and technical equipment in order to reduce carbon and energy footprints. The Living Planet Centre provides a vivid illustration of this new eco-tech 2.0, its energy reduction determined and arrived at through the power of computer modelling. The question that this new orthodoxy begs, however, is whether any other approach to sustainable building that is not informed by new media technology, will remain within the mainstream of zero carbon architecture, or if low-tech approaches are in the midst of being consigned to the margins, or even destined to disappearing altogether into history books.

Renewable energy systems 3,8% External works 7,8%

Structure 11,3%

Regulated operational energy 9,2%

Unregulated operational energy 22,0%

Sanitary (WC, shower, kitchen) 1,5% Facade 6,2%

Operational carbon emissions

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Site preparation, excavation, waste disposal 1,9 %

Roof 6,4% Internal fit out 11,1% 11

Lift 1,3%

Plant/Building services 17,6%

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9 Longitudinal section with energy concept a Cowl for exhaust air (closed in winters) b Solar control glazing with external shading c Earth ducts for passive cooling (6 concrete pipes, 0,9 m diameter, buried 1 metre below car park; total length = approx. 450 m) d Roof-integrated photovoltaic panels (510 m2; peak output 55 kWp) e Displacement ventilation f Two air handling units (maximum air volumes: 7,4 m3/s and 5,4 m3/s, respectively) g High efficiency interior lighting with daylight dimming and occupancy sensors (background light level: 300 lux) h Acoustic tiles with integrated phase change materials i Louvred openings for natural ventilation (open in mid-season) j 35 m3 harvesting tank for greywater and attenuated rainwater k Rainwater overflow to purpose-made swale attenuated to the canal l 20 boreholes, each 100 m deep, connected to 4 ground source heat pumps for heating and cooling (COP: 4 for heating, 4,5 for cooling) 10 Lifetime carbon emissions and reductions achieved during construction 11 Sources of life-cycle carbon emissions over 60 years and their relative impact 12 BREEAM certification results 13 Interior view from the mezzanine level 12

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Results of BREEAM Final Assessment (Version: BREEAM Bespoke 2008) Category

Total score

Weighted score

Management Health & Wellbeing Energy Transport Water Materials Waste Land Use & Ecology Pollution Innovation

100 % 87 % 88 % 93 % 88 % 73 % 86 % 90 % 67 % 50 %

12.00 % 13.09 % 16.63 % 7.43 % 5.25 % 9.17 % 6.43 % 9.00 % 6.67 % 5.00 %

Total score

90.66 %

Result BREEAM Outstanding (Pass: 30 %, Good: 45 %, Very Good: 55 %, Excellent: 70 %; Outstanding: 85 %)

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2014 ¥ 2 ∂Green

Building design with a vision: experimental houses in Nyborg Jakob Schoof

Those who want to see urban sprawl first hand do not have to travel all the way to the Unites States. The phenomenon can also be found in the centre of Europe, for example in Nyborg, a small town with 16,000 inhabitants on the banks of the Great Belt on the Danish island, Funen.

On its western edge, facing away from the sea, the town is surrounded by a wide commuter belt that consists of detached houses characteristic of suburban areas on the periphery of Danish towns: singlestorey buildings with exterior brick or timber walls and low-pitched, tiled hip roofs.

It is in this remote place that the real estate company, Realdania Byg, has built six prototypical houses that are intended to pave the way to a future in which energy-efficient building will become standard and other essential aspects of sustainable construction will also finally be addressed. Among other things, this includes the increased use of recycled materials, durability and maintenance-friendly construction techniques, as well as the consideration of user behaviour. Expressed in simple terms: (almost) all the energy efficiency parameters that are not currently considered in the energy perfor-

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mance certificates of buildings. The relative significance of these aspects is increasing progressively with each tightening of the legal minimum requirements for the energy efficiency of buildings. From 2015 onwards, for example, the construction, maintenance and dismantling of a typical single-family house in Denmark are expected to account for no less than 40% of the total lifecycle CO2 emissions of the building. Only the remaining 60 % of total emissions will result from heating and power consumption, which – by comparison – still make up the bulk of emissions in old, inefficient buildings.

Five of the six ‘Mini CO2 Houses’ in Nyborg are dedicated specifically to one aspect of energy efficiency. The sixth house combines – as a kind of marketable synthesis – many of the features proven successful in the other buildings. Jørgen Søndermark, project manager at Realdania Byg, stresses that the houses are not intended to be experiments without real stakes, but field-tested approaches for the Danish construction industry. It is for this reason that the budget for each was limited to 1.7 million Danish crowns, which is approximately 230,000 euros.

The considerable costs for the design, planning, material enquiries and accompanying research were not included in the price, however, but paid for separately by the client, a subsidiary of the Danish Realdania Foundation, whose primary objective it is to promote innovations in the construction industry.

In order to check the effectiveness of the projects, Realdania Byg commissioned two life cycle assessments for each house – one for an observation period of 50 years and the other for a longer period of 120 years. The houses are to be sold on to private customers before the end of the year. Their marketability will be proof as to whether or not there is a real demand in the market for the solutions that have been tested in Nyborg. The six newbuilds have floor plans ranging from 129 to 157 square metres and already meet the requirements for Denmark’s statutory Low-Energy Standard of 2015. This is achieved, as stressed by Jørgen Søndermark, without the use of photovoltaic panels on the roofs, or any other state-of-theart energy technology. The houses are heated with district heat generated in a nearby waste incineration plant. Three of

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the houses use traditional radiators to distribute the heat, whilst the other three use an underfloor heating system.

A house with a history The first house to be completed in the series is the smallest and one of the most unusual: Realdania Byg, in cooperation with the architectural practice, Lendager, had been pondering for some time with the idea of constructing a house primarily with the use of recycled material.

Their efforts resulted in the Upcycle House, the load-bearing structure of which includes two parallel-aligned discarded shipping containers resting on second-hand steel screw piles, as well as recycled timber beams spanning between them. Concrete has not been used anywhere in the entire building. The space between the two containers is airy and bright, with a hall-like feel, receiving daylight from the clerestory windows above. The character of the room is mainly determined by the wall panelling made of OSB board, which was produced from scrap wood. In the bedrooms and ancillary rooms, the walls have been lined with gypsum plasterboard with a recycled

content of 25 %. The outer skin of corrugated aluminium sheeting has an even higher recycled content of 95 %. The terrace decking is a blend of 40 % recycled paper and 60 % PVC polymers – a waste product from the production of self-adhesive labels. Recycling materials were also used for the kitchen floor, where there is a floor covering made of sliced corks arranged and glued onto a substructure of thick, recycled paper.

There are some interior fixtures and fittings, such as the kitchen cupboards and sanitary ware, which the architects bought from estate sales and simply reused. The floor covering on the veranda is made of bricks from a demolished house and the veranda windows were salvaged from a school in Copenhagen.

The story behind the remaining windows is even more noteworthy: they are rejects from a window manufacturer – completely flawless from a technical point of view, but accidentally made to the wrong size specifications. Lendager Arkitekter had the windows removed from the frames and attached the panes to the timber stud walls using a clamping mechanism. This means that the windows cannot be

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Upcycle House (Lendager Arkitekter): Veranda with flooring made of reused bricks, as well as reused windows from an old school building The living space occupies the central (and highest) part of the building.

South view of the house, with facade cladding made of waste paper and plant-based binders (on the external wall leading onto the terrace) as well as corrugated cladding made of 95 % recycled aluminium Axonometric of the construction a Interior wall made from second-hand plastic jerry cans b Wall covering made from recycled bed linen c Recycled glass tiles d Kitchen floor made from old wine corks e Window panes salvaged from window manufacturer rejects f Corrugated aluminium cladding with a recycled content of 95 % g Waste paper insulation h 45 ≈ 50 mm waste timber battens i 45 ≈ 195 mm waste timber roof beams

k l m n o p q r s t u v w x y z

Facade cladding made from waste paper and plant resin Ø 60 mm post made from recycled aluminium Terrace decking: wood waste/plastic scrap composite Windows salvaged from school refurbishment Veranda floor with recycled glass foam granulate insulation Facade insulation made from waste paper Particle board made from wood waste Kitchen worktop made from reclaimed floorboards Second-hand kitchen cupboards with new coat of paint Veranda floor covering made from recycled roof tiles Gypsum plaster board with 25 % recycled gypsum Adhesive-free OSB panels made from wood waste 45 ≈ 95 mm waste timber floor joists Salvaged 40-foot shipping container Floor insulation made from shredded Styrofoam waste Plinth wall made from an ice-rink surround Foundation system with second-hand steel screw piles

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Resource-efficient steel-composite construction in office buildings

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345 325 305

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285

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265 20

225

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90

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a=3

350

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Comparison of total mass, construction height, ecological rating and costs of different slab types and distances between floor beams (a). Assumptions: Two-span beams made of S355 steel; variable total building depth L = L1 + L2 Ceiling slabs with different configurations of downstand beams and column spans Demand of building materials per m² of gross floor area for the investigated structural systems Degree of ecological achievement and costs of structural systems with downstand beams (trend lines). Assumptions: in-situ concrete ceiling slabs (C30/37), IPE downstand beams (S460) and HE steel columns (S460; length = 350 cm)

a

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height of 100 mm is decisive for profiled sheeting slabs up to a span of approximately 3.6 m. The lower diagram indicates that in-situ slabs are slightly advantageous in terms of their ecological performance, as the higher concrete mass that they require is overcompensated by the ecological cost for galvanising the profiled sheeting.

Pre-stressed slabs are generally only used for larger ceiling spans of 6 to 12 metres. The parametric study shows that this also makes sense in terms of ecology, as the ecological rating of the prestressed hollow-core slabs is significantly lower than that of the other slab types.

Floors with composite downstand beams As can be seen in fig. 5, ceiling spans of up to 4 m are favourable with regard to ecology and economy. The same applies to floor systems with composite beams, even if the proportion of steel profiles per m2 of floor area decreases with increasing distances between beams.

In the left-hand diagrams in fig. 6, the total construction height and the total mass (slab and beam) per m2 of floor area is assessed for various distances between beams and building depths, as well as for in-situ concrete and profiled sheeting slabs. The composite beams are calculated as two-span beams with asymmetrically placed central columns to allow for a corridor in the centre of the building.

Therefore, resulting in two unequal spans: L1 and L2. With an increasing distance between the beams (a), the construction height, the total mass and the mass of the reinforcement also increase, while the mass of the steel profiles per square metre decreases.

The right-hand diagrams in fig. 6 present the ecological rating and the costs for each of the assessed composite floor systems. From the charts, it becomes clear that the slightly higher concrete mass for a beam distance of 3.6 m in comparison to 2.4 m can be compensated by the lower mass of the steel profiles,

Amount of material needed

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Reinforcement [kg/m2] Profile steel [kg/m2] Concrete [10 kg/m2] Distance between columns = 2a, except: *Distance between columns = a

35 30 25 20 15 10 5 0

2,4

3,6 4,8 4,8* 2,4 3,6 4,8 4,8* L = 13 m L = 16 m without central row of columns

and this is the favourable option in terms of environmental performance.

In [1] it has been shown that higher concrete grades (e.g. C30/37 instead of C20/25) do not result in an improvement of the ecological rating of in-situ concrete floor slabs, as the material savings are compensated by the disadvantageous ecological data of C30/37 in comparison to C20/25. The same is true for higher concrete grades in floor systems with composite beams. However, the mass of profile steel can be reduced by the use of higher strength steels as long as the steel grade is decisive for the dimensioning of the beams. The material savings by using S460 in comparison to S235 have a positive effect on both the ecological performance and costs.

Structural systems with downstand beams In order to optimise entire structural systems, their components have to be considered as a whole, as the sum of individually optimised components will not necessarily result in the best overall solution.

Reducing the number of columns, for example, will increase the vertical load on each column, but reduce the cost per kN of vertical loads of the columns. On the other hand, fewer columns results in larger spans of beams and, correspondingly, larger beam sections. Intermediate columns, on the other hand, will reduce the spans of the floor beams but require additional material for columns and, potentially, an additional downstand beam in the centre of the building.

Fig. 7 shows plans of different structural systems with varying configurations of columns and beams. If the distance between beams is smaller than the distance between columns, additional perimeter beams become necessary (fig. 7a and 7c). In deeper office buildings, intermediate supports are often introduced (fig. 7c and 7d). In this case, an asymmetrical configuration of columns is often chosen in order to be able to create a columnfree central corridor in the building.

2,4 3,6 4,8 4,8* L = 10 m

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3,6 4,8 4,8* 2,4 3,6 4,8 L = 13 m L = 16 m with central row of columns

In the parametric studies, the floor beams, as well as perimeter and intermediate beams consist of IPE profiles made of S460 steel as these allow for optimum results in terms of both ecology and economy. The floor slabs are made of C30/37 concrete, whereas the columns (height = 350 cm) consist of HE steel profiles made of S460 steel. The vertical loads on columns correspond to the average loads found in a typical five-storey office building. Three different distances between beams (a) have been assessed: 2.4 m, 3.6 m, and 4.8 m, the assumption being in each case that the distance between columns is twice the distance between beams (2a). For a = 4.8 m, the study additionally investigates one option in which the distances between beams and between columns are equal, thus eliminating the need for perimeter and intermediate beams (fig. 7d).

Fig. 8 shows the material use in kg per m2 of floor space for the investigated options.

The concrete mass per m2 varies only with the distance between beams a, where a = 4.8 m requiring more concrete than floor systems where a = 2.4 m and 3.6 m. The amount of reinforcement steel is lower for the structural systems without 100 90 80

4,8*

intermediate columns than for those with intermediate columns. The total mass of profile steel, on the other hand, is lowest in the option with central columns in which the distance between columns equals the distance between beams (fig. 7d). The mass is highest in the structural system without intermediate columns and with perimeter beams (fig. 7a).

Fig. 9 displays an evaluation of the ecological rating and the corresponding costs of the different options. For the structural systems without intermediate columns (green lines in the diagram), the costs increase moderately and the ecological rating decreases as the building becomes deeper. For the systems with intermediate columns the decrease in the ecological rating is less pronounced. The costs remain almost constant in this case, as on one hand the amount of materials used moderately increases with the building depth, but the number of building elements per square metre (and thus the amount of connections required) decreases. The best results are achieved by the structural systems where the distance between columns corresponds to the distance between beams (grey dashed lines).

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Products and materials

2014 ¥ 2 ∂Green

Doors, windows and facades

High-spec operation speeds pedestrian flow

At E.ON, the revolving entrance minimises the risk of bottlenecks at busy times and helps maintain the lobby’s ambient temperature.

The Universal 5201 was also used at the Beacon facility. In the event of power failure, the door can be used manually to ensure unrestricted access.

Tormax recently installed a three-wing revolving entrance at the Coventry headquarters of E.ON. The door is powered by the Universal 5201 drive, a high-specification operator designed to automatically capture system-specific data for safe motion control at all times. To further improve access, the existing swing doors on either side of the main entrance have been upgraded.

These are powered by iMotion 1301 operators, which benefit from motors with no abrading parts, according to the manufacturer, delivering exceptional durability. The building, accommodating over 1,000 employees of the integrated electricity and gas company, is partly powered by the largest solar installation in the country. The new revolving entrance helps to cut heat loss from the building, contributing to lower energy requirements. An impressive new community facility, the Beacon in Newcastle, also features a glass frontage with revolving doors incorporating a Universal 5201 drive and an automatic swing door with an iMotion 1301 operator. According to Tormax, the low-energy doordrives positively contribute to the sustainability of the building, effectively cutting energy bills by minimising through-draughts.

Tormax United Kingdom Ltd Unit 1, Shepperton Business Park, Govett Avenue Shepperton TW17 8BA, United Kingdom Tel: +44 (0)1932 238040 Email: sales@tormax.co.uk www.tormax.co.uk

Revolving doors that save and generate energy

The NRG+ Tourniket is Boon Edam’s first revolving door that can generate electricity from the energy that users apply to rotate the door.

With the NRG+ Tourniket, Boon Edam has developed a revolving door that not only saves energy, but is also able to convert the energy applied to turn the movement of the door into electricity to power the ceiling lamps. The product is available with three or four door wings with a variety of finishes. It can be equipped with remotely controlled locking, an air curtain, as well as a collapsible door set to make it function as an emergency exit.

To enhance the energy-saving qualities of its revolving doors, the Dutch manufacturer has also introduced a ‘Green Retrofit Package’ comprising a number of measures that can be installed on both new and existing revolving doors. These include weather strips that combine the traditional horsehair with plastic inlays for a 30 % increase in draft reduction. Additionally, a motion detector for automatic revolving doors detects the direction people are walking in the vicinity of the door, thus ensuring the door will only turn when someone actually wants to enter the building. According to Boon Edam, this reduces both the power consumption of the door and the thermal energy losses of the building. Furthermore, the package includes a LED lighting system which, according to the manufacturer, has a longer lifespan and consumes 60% less energy than traditional halogen lamps.

While LED lighting is included in all NRG+ Tourniket doors, it can now also be retrofitted to existing revolving doors via Boon Edam’s new Green Retrofit Package.

Boon Edam Ltd. Holland House, Crowbridge Road Orbital Park, Ashford TN24 0GR, United Kingdom Tel.: +44 (0)1233 505 900 Email: contact@boonedam.com www.boonedam.co.uk

∂Green 2014 ¥ 2

5 Products and materials

Kawneer systems help WWF achieve a carbon first Glazing systems from architectural aluminium system supplier, Kawneer have been used on the new headquarters of the World Wildlife Fund in Woking (UK), not least due to their ability to enable savings in terms of energy and embodied carbon. While Kawneer’s AA 100 mullion-drained and AA 100 SSG (Structurally Silicone Glazed) curtain walling with 50mm sightlines and concealed vents were used on the facades, AA 3110 horizontal sliding doors and 190 heavy-duty commercial entrance doors give access to the £14 million new-build. The systems were put forward by sub-contractor, JPJ Installations for main contractor, Willmott Dixon who, to meet the brief from the conservation charity, forensically tracked the carbon content of every single element of the 8,900m2 building. The carbon budget had assumed that the aluminium framing included 30% recycled content, but JPJ suggested an alternative supplier that could supply 80% recycled aluminium – that supplier was Kawneer.

WWF’s Living Planet Centre is the first building in the UK to have undergone a full, whole-life carbon assessment. It has been built on an elevated concrete structure over an existing car park at the edge of Woking’s city centre. Generous roof lighting (Kawneer’s AA 100 curtain walling) in the diagrid roof provides double the light of a typical office. The building will use 53% less energy than a typical office building and has been certified as BREEAM ‘Outstanding’.

Kawneer UK Ltd Astmoor Road, Astmoor Industrial Estate Runcorn, Cheshire WA7 1QQ, United Kingdom Tel: +44 (0)1928 502500 Email: kuk.kawneer@alcoa.com www.kawneer.co.uk

WWF’s new Living Planet Centre is the first building in the UK to have undergone a full whole-life carbon assessment.

Kawneer’s AA 100 facade systems have been used for the front facades, as well as the roof lights of the 8,900 m2 new-build.

Internal insulation with unprecedented U-value With Kooltherm K13 and K14, Kingspan Insulation is offering two new types of insulated plasterboard for dry-lining the inside of external walls. The rigid thermoset modified resin insulation used for Kooltherm K13 and K14 achieves a thermal conductivity between 0.022 W/mK and 0.019 W/mK, depending on insulation thickness. When applied to a 215 mm solid masonry wall, a 100-mm insulation layer will thus yield a U-value of 0.19 W/m2K. According to Kingspan, the insulation has a Class 0 fire rating, is resistant to the passage of water vapour, and is manufactured with a blowing agent that has zero ODP and low GWP. While Kooltherm K14 has been developed for mechanically fixed dry-lining with the help of timber battens (see photographs), Kooltherm K13 is suitable for adhesive bonded dry-lining of masonry cavity walls or solid masonry walls. Both Kooltherm K13 and K14 have a front facing of 9.5 mm tapered-edge gypsumbased plasterboard which readily accepts dry-jointing materials and plaster skim. Both products typically achieve a vapour resistance far above 100 MN·s/g, and require no additional vapour barrier to be installed with the insulation.

Kingspan Insulation Ltd Pembridge, Leominster Herefordshire HR6 9LA, United Kingdom Tel: +44 (0)1544 388601 Email: info@kingspaninsulation.co.uk www.kingspaninsulation.co.uk

Kingspan’s Kooltherm K14 Insulated Plasterboard is fixed to the inside surface of masonry walls by means of timber battens.

The new products combine insulation, drylning and vapour control in one board.

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Planners and manufacturers/Photo credits

2014 ¥ 2 ∂Green

Page 20 Students’ centre in London 1 Sheffield Street London WC2A 2AP, UK

Page 28 Office building in Woking Rufford House, Brewery Road Woking GI21 4LL, UK

Page 36 Multi-family house in Hamburg Am Inselpark 7 D-21109 Hamburg

• Client: London School of Economics and Political Science, Estates Division, London • Architects: O’Donnell+Tuomey Architects, Dublin • Structural engineers: Dewhurst Macfarlane and Partners, London Horganlynch Consulting Engineers, Dublin • Building services and environmental engineering: BDSP Partnership, London • Security, fire protection, acoustics, transport & logistics: Arup, London • Catering: Tricon Foodservice Consultants, Barking • Project manager: Turner & Townsend, London • Quantity surveyor: Northcroft, London • Building control consultant: Carillion plc., Croydon

• Client: WWF UK, Woking • Architects: Hopkins Architects, London • Structural engineers: Expedition Engineering, London • Environmental design consultants: Atelier Ten, Glasgow • Life cycle assessment: Sturgis Carbon Profiling, London • Landscape architects: Grant Associates, Bath • Project management: JEB Project Management Services & Doherty Baines, London • Exhibition design (The WWF Experience): Jason Bruges Studio, London

• Client: Woodcube Hamburg GmbH, Hamburg • Architects: architekturagentur, Stuttgart • Structural engineers: Isenmann Ingenieure, Haslach • Building physics, fire protection: TSB Ingenieure, Darmstadt • Building automation: InHaus GmbH, Duisburg • Life cycle assessment: ina Planungsgesellschaft, Darmstadt

• Main contractor: Geoffrey Osborne Ltd., Reigate • Bricks: Coleford Brick & Tile Ltd., Cinderford • Bricklayers: SWIFT Brickwork Contractors, Chelmsford • Timber windows: GEM Group, Longford • Aluminium windows: Schüco, Westcliff-on-Sea • Concrete works: Foundation Developments Ltd., Wallington • Roofing: Rheinzink UK, Frimley

• General contractor: Willmott Dixon Construction, Letchworth Garden City • Concrete works: Lafarge, London • Curtain walling: Kawneer UK, Runcorn • Aluminium roof: Rigidal, Worcester • Wind cowls: Vision Ventilation, Waterlooville • Architectural steel work: Bailey Fabrication Ltd., Gosport • Photovoltaics: SunPower, Solihill • Heat pumps: Groenholland, Havant • Furniture: Kinnarps UK, London • Flooring: InterfaceFLOR, Halifax Nora, Rugby

• Timber construction: Erwin Thoma Holz GmbH, Goldegg • Concrete works: H. Mierwald GFS, Hamburg • Heating, ventilation, sanitary installations: B. H. Daehn & Co. GmbH, Hamburg • Electric installations: Thomas Elektro GmbH, Hamburg • Drywall construction: Fermacell GmbH, Duisburg (Manufacturer), EBS Ltd. & GmbH, Munich (Construction works) • Lift: Kone GmbH, Hannover • Gardener: König Garten- und Landschaftsbau, Hamburg • Windows: Stelzer Alutechnik GmbH, Gammertingen • Thermal insulation: Gutex Holzfaserplattenwerk, Waldshut-Tiengen • Interior paints, ETICS: Keim Farben, Diedorf • Membranes, Sealants: Proclima, Schwetzingen

Photo credits: Photos for which no credit is given were either provided by the respective architects or manufacturers, or taken from the DETAIL archives Pages 4, 19 top ,21, 22, 23 top, 26, 27, 44, 45, 46 bottom, 48, 50 top left, 61: Jakob Schoof, Munich Pages 5, 6 bottom: Jason Flakes, Annandale Page 6, top: Università degli Studi Roma Tre, Rome Pages 8, 9: Hufton + Crow, London Page 10: Michael Heinrich, Munich Page 11: Tord-Rikard Söderström, Stockholm Page 12: Sergio Grazia, Paris

Page 16: Thomas Ott, Mühltal Page 17: Michael Egloff, Zurich Page 18: HHS Architects + Planners, Kassel Page 19, bottom: Sascha Kietzsch, Munich Page 22 bottom, 24 bottom, 25: Dennis Gilbert/VIEW Page 24 top: Christian Schittich, Munich Pages 28, 29, 30 right, 31, 33, 35 top, 69 top: Morley von Sternberg, London Page 36: Falcon Crest/IBA Hamburg GmbH

Page 37: Patrick Sun/IBA Hamburg GmbH Pages 38, 39: Bernadette Grimmenstein/IBA Hamburg GmbH Pages 40, 41, 42: Martin Kunze/IBA Hamburg GmbH Page 46 top, 50 top right: Hagen Stier, Hamburg Pages 49, 50 bottom: Meike Hansen/Archimage, Hamburg Pages 52−57: Jesper Ray, Birkerød Page 69, 2nd from top: Richard Stonehouse/WWF

∂Green 2014 ¥ 2

Imprint

∂ Green Specialist Journal for Sustainable Planning and Construction Published by: Institut für internationale Architektur-Dokumentation GmbH & Co. KG, Hackerbrücke 6, 80335 Munich, Germany Tel.: +49 (0)89-38 16 20-0 Fax: +49 (0)89-33 87 61 www.detail.de/english P. O. Box: Postfach 20 10 54, 80010 Munich, Germany

Page 44 Education complex in Hamburg Krieterstraße 2 D–21 209 Hamburg • Client: GMH Gebäudemanagement Hamburg GmbH, Hamburg • Architects: bof architekten, Hamburg • Tender and site supervision: bof architekten Hamburg DGI Bauwerk GmbH, Hamburg • Structural engineer: Schumacher + Gerber, Hamburg • M&E engineering: EGS-plan GmbH, Stuttgart Ridder & Prigge, Hamburg • Landscape architects: Breimann & Bruun, Hamburg • Lighting design: Peter Amdres, Hamburg • Fire protection consultants (building): WTM Engineers, Hamburg • Fire protection consultants (timber facade): I. Kotthoff, Leipzig • Concrete works & masonry: Riedel Bau, Schweinfurt • Timber element facade: Zimmerei Sieveke, Lohne • Drywall construction and interior fit-out: TM Ausbau GmbH, Puchheim • Metal roofing: Kalzip GmbH, Koblenz • Linoleum flooring: DLW Armstrong GmbH, Bietigheim-Bissingen • Metal doors: Forster AG, Arbon • Windows: KOWA Holzbearbeitung GmbH, Goldenstedt

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