Issue 8 December 2018
Journal
Sustainable Design & Applied Research in Engineering and the Built Environment
The SDAR Journal is a scholarly journal in sustainable design and publishes peer reviewed applied research papers Cover SDAR Journal 2018.indd 1
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BUILDING ENGINEERING MECHANICAL, ELECTRICAL & ARCHITECTURAL DESIGN What is Building Engineering? A building can be likened to a human body - the human body has a skin (preferably without leaks!) and so does a building, both using skin to regulate temperature. The body has a heart which pumps blood and heat around the body, similar to a heating system in a building; a respiratory system that takes in fresh air and exhales stale air just like an air-conditioning system and a brain that acts as a control centre for all these systems. And just like the human body, a building has a brain – the Building Engineer – whose job it is to ensure that the building is a pleasant and productive place for the people that occupy it.
DIT is an innovator in this discipline and our graduates are in high demand as we have the only Level 8 accredited Building Engineering programme in Ireland.
DO YOU HAVE WHAT IT TAKES
YOU ARE ADAPTABLE You can travel anywhere in the world with these skills working for top Irish companies or you can work for yourself.
You can study to become a building engineer in a variety of streams. You do not necessarily have to have a Leaving Cert honours maths qualification.
For more information contact: DT026 B.Eng. Building Engineering - Level 8 Brian Clare (Programme Chair) E: brian.clare@dit.ie T: (01) 402 3973 DT005 B.Eng.Tech Building Engineering - Level 7 Chris Montague (Programme Chair) E: chris.montague@dit.ie T: (01) 402 3833
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YOU ARE AMBITIOUS You want high earnings and the lifestyle to match but you also recognize that money and status is nothing unless you really are making a difference in the world.
DT033 Part-time Option – Level 7
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Noel O’Neill (Programme Chair) E: noel.oneill@dit.ie T: (01) 402 3909
You will be on the frontline of a new engineering revolution. You will design and power great things while reducing carbon emissions You will build a sustainable career.
Ciara Ahern (Head Of Discipline) E:ciara.ahern@dit.ie T:(01) 4023826 Ms Miriam Daly (School Administration) E: miriam.daly@dit.ie T: (01) 402 3659
06/11/2018 11:03
Contents 5 The present and future of lighting research PR Boyce PhD prb.lrt@btinternet.com
15 A case study of energy efficient measures undertaken in an industrial facility Tommy Shannon tommy.shannon@excel-industries.com
29 A matched pair of test houses with synthetic occupants to investigate summertime overheating in dwellings Ben M. Roberts, Loughborough University b.m.roberts@lboro.ac.uk David Allinson, Loughborough University d.allinson@lboro.ac.uk Kevin J. Lomas, Loughborough University k.j.lomas@lboro.ac.uk
41 The built environment and its patterns – a view from the vision sciences
Prof A J Wilkins, Department of Psychology, University of Essex email: arnold@essex.ac.uk
Introduction Welcome to the SDAR Journal which the Chartered Institution of Building Services Engineers (CIBSE Ireland) produces in partnership with the Dublin Institute of Technology (DIT). It is the eigth edition of the journal, which has gone from strength to strength down through the years, thanks in particular to the commitment and dedication of the editorial teams and reviewing panels involved each year. The main objective of the SDAR Journal is to promote sustainable design and applied research and, having read the spread and diversity of papers in this issue, I’m sure you will agree that building services engineering has a great deal to offer in shaping the future of our environment for years to come. This edition has again proved to be an excellent production with papers by Irish and international authors whose time and dedication to excellence in research and design should be applauded. The SDAR Journal has been downloaded 27,000 times (from 100 countries) and, when employers are looking for the perfect candidate for a position, there is no doubt that having a paper published in the journal elevates the candidate to the top of the pile. I wish to thank all of the researchers, authors, reviewers and editorial team on behalf of CIBSE Ireland for all of their great work, and I hope you will all take something from this publication that will go towards a more sustainable and safer environment.
Dr Olivier Penacchio, Department of Psychology, University of St Andrews email: op5@st-andrews.ac.uk
Paul Martin BEng Hons, CEng, FCIBSE CIBSE Ireland Chairperson (cibseirelandchair@gmail.com)
Dr Ute Leonards, School of Psychological Science, University of Bristol email: Ute.Leonards@bristol.ac.uk
Since its inception the Journal of Sustainable Design and Applied Research (SDAR
51 What we can we learn from the Grenfell Tower disaster: priorities for sustainable change Hywel Davies, Technical Director, CIBSE hdavies@cibse.org Editor: Professor Kevin Kelly, DIT and CIBSE Contact: kevin.kelly@dit.ie Deputy Editor: Kevin Gaughan DIT Contact: kevin.gaughan@dit.ie Editorial Team: Kevin Gaughan, Yvonne Desmond, Keith Sutherland, Avril Behan, Michael McDonald, Paul Martin, Ciara Aherne, Brian Widdis, Pat Lehane, Kevin Kelly. Reviewing Panel: Kevin Donovan, Joseph Little, Kevin Gaughan, Mona Holtkoetter, Paul Martin, Dr James Duff, Dr Derek Kearney, Prof David Kennedy, Dr Marek Rebow, Dr Ciara Ahern, Dr Keith Sunderland, Dr Emma Robinson, Dr Martin Barrett, Dr Avril Behan, Dr John McGrory. Upload papers and access articles online: http://arrow.dit.ie/sdar/ Published by: CIBSE Ireland and the College of Engineering & Built Environment, DIT Produced by: Pressline Ltd, Carraig Court, George’s Avenue, Blackrock, Co Dublin. Tel: 01 - 288 5001/2/3. email: pat@pressline.ie Printed by: W&G Baird Ltd
Journal) has been published by CIBSE in association with Dublin Institute of Technology. The journal represents an outstanding example of the synergies that result from very close cooperation between professional bodies and higher education institutions, and is now a significant mechanism by which the outcomes of research and development become available to, and are translated into, practice. We live in an era where very low energy smart buildings are fast becoming a reality. In this context, the SDAR Journal has been a conduit for communicating key developments that will continue to reinvent and recast what “building services engineering” actually is. Change is not only fundamental to our profession but also to higher education. With effect from 1 January 2019, the Dublin Institute of Technology, the Institute of Technology, Blanchardstown and the Institute of Technology Tallaght will be designated as Technological University Dublin. Education at TU Dublin will be career-focused, practiceled and research-informed. It will offer programmes from apprenticeships to PhD for school leavers, for those seeking advanced studies and for career advancement or change. To be a major force for innovation the proportion of research students will increase from 4% to 7%. At this pivotal point in the history of DIT it is particularly timely to pay tribute to our distinguished colleague Professor Kevin Kelly. Kevin will be an Emeritus Researcher in TU Dublin but has recently retired as Head of the School of Multidisciplinary Technologies in DIT. As Editor Kevin has driven the SDAR Journal, maintaining a distinctive approach that has met a real need. As and from January, the Journal will be a jewel in the crown of TU Dublin. We look forward to your continued support as authors, readers and users of the information contained in the articles.
ISSN 2009-549X © SDAR Research Journal. Additional copies can be purchased for F50
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Professor Brian Norton President DIT, Honorary Fellow CIBSE
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SDAR Journal 2018
Editorial
Editorial Board
This is a challenging time for all building professionals in the built environment. In the UK the calamitous affects of Grenfell have had an awful impact on the many people affected, and they are being roundly felt by all in the industry. As a result, there is a determination there to change the culture across all sectors of the industry. In Ireland, we too have had a nasty fire in the multi-storey Metro Hotel building in Ballymun. We also had to close (in some cases temporarily, in others maybe long-term) over 20 schools because of issues with construction. Previously we had problems with fire and safety standards in buildings that have resulted in costly and disruptive correction measures for residents and owners. Thankfully, so far all of this has been without fatalities. However, many of us still remember the Stardust fire and know that complacency is never an option in this regard. We must face up to our issues in Ireland, especially those relating to procurement and the “mere minimum compliance” approach. As Dame Judith Hackett concluded from her review of practice in the UK, we have to change the culture from one of minimum compliance to one where buildings will be assuredly safe. This requires a whole change of mind-set for government, and clients generally, as well as the industry itself. This edition of the SDAR Journal carries an invited paper from CIBSE Technical Director Dr Hywel Davies about the Grenfell review in the UK, and it has lessons for us all. While we strive for modern sustainable buildings, we must as a priority also make sure they are safe for their occupants. There is no suggestion that these two essential aims are in any way mutually exclusive … on the contrary, they align well.
Professor Brian Norton Dublin Institute of Technology Professor Andy Ford London South Bank University Professor Tim Dwyer University College London Dr Hywel Davies CIBSE Technical Director Paul Martin Chairman, CIBSE Ireland Professor Gerald Farrell Dublin Institute of Technology Professor John Mardaljevic Loughborough University Professor Michael Conlon Dublin Institute of Technology Professor David Kennedy Dublin Institute of Technology Professor Tony Day International Energy Research Centre – Cork Professor Kevin Kelly Emeritus Researcher, TU Dublin, Vice-President CIBSE, Past-President SLL
Looking to the future, one of the aims of the SDAR Journal is to provide a platform for working engineers to publish their “real world” project performances and cutting-edge practices. Safety is at the top, followed by sustainability and then modern, efficient construction practices. We would welcome abstracts and submissions on these issues for next year’s publication to kevin.kelly@dit.ie We will provide support to working engineers, and new writers, where this is requested
.
Professor Kevin Kelly C Eng FCIBSE FSLL Emeritus Researcher, TU Dublin Vice-President CIBSE Past-President SLL kevin.kelly@dit.ie
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A Reader’s Guide Professor Peter Boyce delivers a paper that outlines the gaps in knowledge in lighting research internationally, both today and in what the future may hold. Professor Boyce is Editor in Chief of what is probably the leading lighting research journal worldwide, Lighting Research & Technology. It receives over 200 papers per year and publishes eight editions per annum. In this regard, there is no one in the world better placed to identify the emerging lighting research areas. He does this succintly and his paper is a “must read” for those involved in lighting. Boyce’s review of the topics range from residual studies on visibility and visual discomfort, through attempts to identify the influence of lighting on factors beyond visibility such as mood and behaviour, to the whole new field of light and health. But activity alone is not enough to justify a future, he argues. For lighting research to have a future it is necessary for it to be influential and focus its attention on outcomes that matter to people. Thomas Shannon, a company CEO and an engineer, provides an excellent account of energy efficiency measures investigated and implemented in a manufacturing facility in Ireland that led to substantial savings in energy bills and CO2 emission reductions. These measures could be applied in many companies. Simple and effective, and a good example of applied research in everyday engineering practice.
The paper from Roberts and Lomas, Loughborough University, addresses the problem of overheating in houses in summer. It is based on a presentation made at this year’s CIBSE Symposium in London South Bank University and is an excellent example of the links between CIBSE and the SDAR Journal. The
methodology is also interesting. They adapted two adjoining, semi-detached houses to create a matched pair of test houses for full-scale, side-by-side overheating experiments under real weather conditions. Synthetic occupancy was applied with dynamic remote control of actuated windows, motorised curtains, automated internal doors and internal heat gains. The houses were provided with calibrated sensors to measure the internal and external conditions. Wilkins, Penacchio and Leonards provide a psychologist’s insight, and a different perspective than we are used to seeing, into the effects everyday visual patterns in buildings can have on the people both indoors and outdoors. Highly-geometric and repetitive patterns
can be aversive; patterns in our visual environment are rarely considered with regard to their impact on brain, behaviour and well-being. Patterns in public spaces can lead to discomfort, avoidance behaviours and falls, particularly in older citizens. Recent developments in analysis now allow us to measure and predict adverse effects of patterns in the real world. This insightful paper reviews the evidence of neurological behaviour effects arising from aversive patterns in “real world” examples. It is a “must read” for architects and engineers and is part of a series of such presentations and papers by Professor Wilkins on this topic. The catastrophic fire at Grenfell Tower in London in 2017 killed 72 people and shocked the world. Subsequently, Dame Judith Hackett was appointed by the UK Government to lead the independent review of Building Regulations and Fire Safety in the UK. Dr Hywel Davies, Technical Director of CIBSE, represented CIBSE in that review and chaired one of the working groups established. In this paper he informs us of the lessons learned in the UK. However, these lessons apply much more widely than just to the UK, and in a far more widespread way to just fire safety. Dame Hackett expressed shock regarding some of the practices in the UK. She has called for a change of culture from one of minimum compliance to one that delivers a safe system. This paper summarises the activity associated with the review and where changes in practice are needed in the UK. Davies concludes that the industry must change in order to reduce, as far as is humanly possible, the prospect of any such horrific fire ever occurring again. 3
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Enhancing Thermal Mass Performance of Concrete
The present and future of lighting research
Professor PR Boyce PhD peter.robert.boyce@gmail.com
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Abstract
1. Introduction
The aim of this paper is to consider where lighting research is
In 2004 I published a paper entitled Lighting research for interiors: the beginning of the end or the end of the beginning[1]. It is always instructive for anyone attempting to predict the future to assess how accurate they were in the past, so the objective of this paper is to review what has happened since the publication of that paper and to consider where lighting research is likely to go in the future. The essential message from that paper was that to flourish, lighting research had to move beyond studies of the effects of lighting on visibility and visual discomfort. Specifically, it had to address questions about how lighting influences mood and behaviour through the “message” that lighting delivers to the perceptual system, as well as how lighting affects health and performance through what was then called the circadian system. Now it is more correctly called the non-image forming system. A move in that direction has certainly happened.
today and what its future might be. There is little doubt that, today, lighting research is an active field. A brief review of the topics being studied reveals that they range from residual studies on visibility and visual discomfort, through attempts to identify the influence of lighting on factors beyond visibility such as mood and behaviour, to the whole new field of light and health. But activity alone is not enough to justify a future. For lighting research to have a future it is necessary for it to be influential. To become influential, research needs to focus its attention on outcomes that matter to people and the elements of those outcomes on which lighting is known to have a major influence. Further, researchers will have to be determined to overcome the barriers to changing lighting practice. By doing this, lighting research may change the world for the better, to be an important topic, not an irrelevance. Keywords Lighting, research, future, technology, measurement, design, performance, health. Glossary Photopic vision Occurs under daylight and conventional interior lighting. It is characterised by fine discrimination of detail and good colour vision. Mesopic vision Occurs under outdoor lighting at night. It is characterised by poor discrimination of detail and limited colour vision. Scotopic vision Occurs in the absence of any lighting. It is characterised by no discrimination of detail and no colour vision.
There are still papers published on specific visibility issues such as the seeing of trip hazards when walking on the streets at night[2], the ability to acquire information from traffic signs[3], and the marking of a work-zone on a motorway[4]. Likewise, there are still papers published on discomfort glare[5], [6] and, somewhat surprisingly, flicker[7], the latter being driven by the widespread introduction of LEDs with their very fast response times. Despite these, the last decade has seen a major shift in lighting research away from visibility and visual discomfort to work on perception and its consequences[8], [9], and to work on the use of lighting to ensure circadian stability[10] and improve work performance through increased alertness and cognitive function[11, 12]. From this it might be thought that lighting research is flourishing but I fear that it is not. Indeed, I rather suspect that the current state of lighting research might be compared to a fly in treacle, a lot of energy is being expended but it is not going anywhere. There are a number of reasons for this but, before getting to them, it is necessary to consider what the areas of active lighting research are currently.
2. The present 2.1 Technology Lighting technology is always an active research area, although this is not always evident as little is published in the open literature until the resulting products are ready to market. Nonetheless, the dramatic growth in the adoption of solid-state lighting over the last decade is evidence enough that commercial research on light sources has certainly been active, so much so that academic papers are now appearing that offer ways to improve the colour properties of existing LEDs[13], limit the glare from LED luminaires[14], and provide better ways to estimate the life of LED luminaires[15]. By combining LEDs in different ways, a wide range of light spectra can be constructed. This has led to a resurgence of research on colour metrics[16-20]. Further, the light output of solid-state light sources is easy to adjust. This, combined with developments in information technology and wireless communication, has encouraged the development of control systems responsive to human activity and daylight availability[21], [22]. These developments offer the prospect of lighting ceasing to be a relatively inflexible building
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service and to it becoming a stimulating accompaniment to everyday life. 2.2 Measurement Another area of lighting research where there have been significant developments is in the field of measurement. The most obvious changes have been the decrease in size and price of what, until recently, were very sophisticated measurement tools[23]. As a result, it is now quite common for luminance distributions to be measured using high dynamic range imaging[24], for spectral distributions to be measured using hand-held spectroradiometers[23], for what people are looking at to be identified using eye trackers[25], and for data on peoples’ perceptions to be collected for virtual lighting installations using the internet[26]. Such tools allow measurements to be made that once were either impossible or impractical, and therefore open up new fields of study. While such measurements have been shown to be useful, the potentially most significant change in lighting measurements has had nothing to do with equipment. Rather, it has to do with the recognition that there are multiple spectral sensitivities operating in the retina, depending on what combination of the five types of photoreceptors present in the retina are active under different conditions, how their signals are connected, and the routes they take through the brain[27]. Despite this complexity, light as a physical quantity is still defined by applying the CIE Photopic Luminous Efficiency Function (VȜ) to the spectral power distribution. Every basic photometric quantity, luminous flux, luminous intensity, illuminance and luminance is defined using the VȜ function; yet VȜ represents only the outputs of the longand medium-wavelength sensitive cones. When the main concern of people providing lighting was to ensure that people could see the detail they needed to see, VȜ was a reasonable way to measure light as it reflected the response of the fovea which is what we use when wishing to examine something closely. Although this is still an important aspect of lighting, other aspects of vision involving additional photoreceptors are now considered to be worth consideration, e.g., off-axis detection when driving, the perception of brightness and stimulation to the circadian system[27].
with the development of improved photocopiers and better (or ubiquitous use of) display screens. Even when they have not, there are other technologies available that can do the task better than a human using unaided vision. Hence, he recommends that the purpose of interior lighting should be changed from ensuring adequate visibility so that tasks can be done quickly and easily, without discomfort or fatigue, to first lighting the space so that it is perceived as having adequate illumination, and then providing a hierarchy of light to suitably emphasise objects and surfaces of interest, including any tasks that require special lighting. This approach requires a different set of metrics and measurement procedures. Specifically, lighting recommendations would no longer be made in terms of illuminance on the task plane, usually assumed to be horizontal, but rather in terms of mean room surface exitance and task/ ambient illuminance ratio. This approach is capable of being applied to a wide range of situations, from simple open interior spaces where there is no knowledge of what is to be done in the space, to a sculpture gallery where a great deal is known about what will go where and how it will be viewed. Essentially, this approach can be called a perceptionbased approach to lighting design[31]. In a way, it represents the change in how lighting is considered, from illumination engineering to environmental design. 2.4 Performance While the fundamentals of how lighting and task characteristics affect visual performance are well established[32], there are still papers dealing with specific tasks, usually tasks where the stimulus is characterised by multiple contrasts and colours. For example, Fotios et al have been active in studying the ability to recognise intent from facial expression under street lighting[33], while Mundinger and Houser have shown that, contrary to popular belief, surgeons have no particular preference for the CCT of operating lights[34].
2.3 Design
A more general trend in research related to performance has been the move away from simple visual tasks to looking at how stimulation of the non-image-forming system by light affects the performance of cognitive tasks and the intermediate condition of alertness[35]. This move started by looking at how alertness and cognitive performance could be enhanced during a night shift by the suppression of the hormone melatonin[36]. Then attention switched to what effects there are on alertness and cognitive task performance following light exposure during daytime[37]. While the cost and benefits of melatonin suppression for performance at night are well established, the same cannot be said for daytime exposure when melatonin concentration is at a minimum, although other hormones such as cortisol are certainly present and are influenced by exposure to light.
Another area of active research interest is design. Using conventional experimental techniques and sophisticated statistics, different lighting designs have been shown to influence perceptions of spaces and products[29]. This has commercial significance but the most interesting research is more fundamental. Cuttle has argued the need to change the purpose of lighting of interiors in general[30]. He argues that basing interior lighting recommendations on visual performance can no longer be justified. With few exceptions, light is now inexpensive enough and illuminance recommendations are high enough to ensure good levels of visual performance, especially as visual tasks have become easier
There are a number of reasons why this is a difficult area to study. First, the impact of light exposure on the non-image-forming system depends on the retinal irradiance, the light spectrum, the timing of the exposure, the duration of exposure and the photic history of the individual. Usually, only one or two of these factors are considered in experiments. Second, the performance of cognitive tasks depends on many factors, lighting being just one of them. Third, there seem likely to be several different routes to the intermediate conditions such as alertness. For example, it has been shown that both short wavelength (blue) and long wavelength (red) light can increase alertness, but the
Although a number of alternative luminous efficiency functions for brightness perception and circadian stimulation have been proposed[27], [28], to date, VȜ and the scotopic equivalent (VȜ’) – which reflects the activity of the rod photoreceptors – are the only ones recognised for photometric measurements. Until this limitation is admitted and a series of spectral sensitivities for different effects approved,it is unlikely that lighting will be able to achieve its full potential.
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non-image-forming system is only sensitive to short wavelength light[38]. This might be expected because compared to the visual system, the non-image-forming system is slow, insensitive and non-locating. From an evolutionary point of view, relying on such a system to alert you about danger is a recipe for extinction. To summarise, while performance is still a topic of interest because of its relationship with productivity and wealth generation, research activities have generally moved on from the relative simplicity of the effect of light on visual performance to the more complex area of cognitive performance and the effects of light operating through the non-image-forming system. This is an interesting but difficult field of study and, as a result, there is no coherent understanding of the role of lighting at present. 2.5 Health The ability of optical radiation to damage both eye and skin tissue has been appreciated for many years with the result that there exist standards and guidance about maximum levels of exposure to light[39]. The advent of phosphor-converted LEDs as a major light source with their peak emission in the short wavelength visible has resurrected interest in this field, particularly the blue light hazard[40]. Similarly, the fast response time of LEDs and their resulting sensitivity to any instability in the LED drivers has resurrected interest in flicker as a cause of migraines and illusions, resulting in more standards and guidance[41]. But one aspect of health, and its rather more nebulous companion well-being, that has generated a lot of research activity has been the effect of light on the non-image-forming system. It is well established that long-term and frequent disruption of the human circadian system is often associated with serious ill health[42]. This has resulted in efforts to discover how light can be used to limit circadian disruption[11]. Of course, one possibility would be to insist that everyone should sleep at night and be awake by day but this is seen as unrealistic in what has become a 24-hour society. For those who have to work at night, particularly those working rapidly-rotating shifts, schedules of exposure to light have been proposed to minimise circadian disruption while ensuring adequate performance[43]. For those who sleep at night and work during the day, there is considerable interest in ensuring enough light exposure to stabilise the circadian system. One way to do this is to go outside in the middle of the day but this may not always be possible, or effective, depending on the weather or the location. This has resulted in attempts to make lighting more effective in stimulating the non-image-forming system either by increasing the ingress of daylight into a building, by changing the spectrum of the electric lighting to provide more short-wavelength emission, or by increasing the illuminance provided at the eye by the electric lighting. These have all been approaches aimed at the general population. However, there are some groups whose health is known to benefit from enhanced light exposure. One such group are those who suffer from seasonally-affective disorder. Exposure to bright light during periods of limited daylight has been shown to alleviate the symptoms of this condition[44]. Another group who have been shown to benefit from enhanced exposure to light at the right time are those who suffer from dementia[45]. Delivering light to the eyes of such people during the day is not easy using conventional lighting so a simple light table has been suggested[46]. There is little doubt that light and health has
become a major area of research as it has the potential to improve the lives of many people.
3. The future From the above it should be clear that lighting research has been very active. The question now becomes, what is its future? Before that question can be answered it is necessary to consider what determines its future. This is its value to society and that, in turn, depends on the reasons it was undertaken. Lighting research can have a number of different objectives. One is to develop a new product … a light source, a luminaire, or a control system that can be marketed and sold at a profit. Another is to gain new knowledge so as to explore a new concept or to develop a new model from which predictions about future uses can be made. Yet another is to change lighting practice so as to deliver the lighting that people desire in a sustainable and economic manner. How recent lighting research fits into this framework will now be considered, as will what is required from research to achieve these objectives. 3.1 New products The history of lighting is a story of innovation. From incandescent to discharge to solid-state light sources, the story has been one of steady development interspersed with sudden and dramatic changes. The advent of solid-state lighting and the disruptive effects it is having on the lighting industry is only the latest of these changes. The brutal truth is that, whatever lighting equipment offers a good combination of luminous efficacy, appropriate light output, reasonable colour properties and a long life, all at an attractive price, that equipment will be widely adopted. Solid-state light sources are still being developed but the areas of research that seem most likely to be influential in the future are in the areas of artificial intelligence applied to lighting controls and 3D printing applied to luminaire design. It is not science fiction to believe that homes and workplaces equipped with lighting that has learnt the preferences of the occupants in different situations will soon be with us. But it is not enough to have a product that is new. Newness, itself, is of interest to only a few. What is essential for widespread adoption is that the product should offer something that was not possible before, something that makes a desirable outcome achievable in a convenient manner, at a reasonable price. Lighting research to achieve such products is ongoing. How successful it is will be for the market to decide. 3.2 New knowledge The search for new knowledge might be thought of as an academic exercise; certainly, generating new knowledge is the key to academic success. Yet new knowledge is also the key to new ideas and new products. Consider what has followed from the discovery of the intrinsically-photosensitive retinal ganglion cells and their link to the non-image-forming system. The consequences have ranged from a large number of studies exploring the effects of different light spectra, different radiant flux, different timing and different durations of exposure leading to a number of models of the impact on melatonin concentration, as well as a new way to represent circadian disruption. These, in turn, may lead to light sources weighted to provide a high level of circadian stimulation and lighting designed to
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The present and future of lighting research
provide both visibility and circadian stimulation. Before this can happen, there will need to be some consensus reached on the best way to quantify the circadian stimulation provided. Unfortunately, outside of the field of circadian stimulation, there has been little by way of new concepts or models. It is true there is a new model for discomfort glare[47] but this is of little practical interest because discomfort glare is largely a non-problem today. Luminaire designers know how to minimise discomfort glare. A similar situation is evident for work on the calculation of mesopic luminances[48]. Luminances far into the mesopic region are rare. Most outdoor lighting standards recommend luminances in the low photopic or high mesopic range so the consequences of correcting for mesopic luminance are minimal. There have also been a few studies looking at the life-cycle costs of lighting[49], [50] but these have had little impact. Where interest has been rising is in the psychological effects of lighting. Studies of learning in schools[51], recovery from medical operations[52] and perception of brand identity[29] have all demonstrated that the form of lighting used can have beneficial or detrimental effects on desirable outcomes. These effects tend to be probabilistic rather than certain and are associated with specific situations. Nevertheless, in the given situation they can be real enough and suggest that lighting has a consistent role to play in influencing behaviour. Yet other studies have been devoted to exploring the effect of lighting conditions on mood and behaviour[53-55]. Many of these studies can be considered to be proof of concept studies, i.e., they seek to establish that lighting does have an effect on the specific outcome and therefore should be considered when studying all the factors. Unfortunately, this is just the first step on what is likely to be a long and tortuous path to a full understanding resulting in a model capable of quantifying the role of lighting. An example of such a development is the work of Veitch et al[56]. This reports two laboratory studies using simulated office spaces in which temporary office workers did a range of office tasks over a day. Two statistical analyses of the data revealed a series of links which demonstrated that people who perceived their office lighting to be of higher quality rated the office as more attractive, reported a more pleasant mood and showed greater feelings of health and well-being at the end of the day. Other studies have demonstrated that satisfaction with lighting contributes to greater environmental satisfaction, which in turn leads to greater job satisfaction, a factor that influences organisational commitment[57]. The defining feature of such models is that lighting is just one among many aspects of the situation that have to be considered when estimating the likelihood of the desired outcome, no matter whether it be mood, behaviour or cognitive task performance. Further, all three of these outcomes depend on the context. For example, if the context is a shop and the desired behaviour is for an item on show to be sold, there is no doubt that the way the item is lit has a role to play in making the item look attractive. The way the space is lit also has a role to play in bringing people into the shop and establishing the atmosphere they experience when inside. Unfortunately, the same could be said about the acoustic and thermal shop environment, the attitude of the shop staff and the price of the items on display, as well as the shopper’s finances and recent experiences completely unrelated
to a possible purchase of the item. Given this complex pattern of potential factors influencing the desired outcome, it is very difficult to establish a model that reliably quantifies the role of lighting in achieving the desired aim. At the very least it will require multidisciplinary studies in a clearly-defined context, studies that are both expensive and time-consuming. It is unlikely that many such ambitious studies will ever be undertaken. Given the difficulty of generating models of the effects of lighting on outcomes remote from visibility, does this mean that research in these areas is impossible? I think not, although what is possible will be less ambitious. Basically, what is proposed is to restrict study to whatever aspects of the desired outcome are primarily determined by lighting. In much the same way that visual performance has been separated from task performance by studying it using tasks where the nonvisual components have been minimised, the suggested approach for the shop would be to study how lighting can be used to make the item to be sold most attractive, and how the ambient lighting affects people’s perception of the atmosphere in the shop. The rationale for such an approach would be that the best identified lighting would be making as big a contribution to the desired outcome as it could, any failure to achieve the desired outcome being most likely due to some other non-lighting factor. It is this approach that has led to the studies on how lighting affects alertness described above, the assumption being that an alert individual will perform any task better than one who is sleepy. Such studies would certainly be less expensive and less difficult than attempting to identify the role of lighting among a host of competing factors and, thus, represent a practical way forward for studying such probabilistic outcomes as mood, behaviour and cognitive task performance. 3.3 Changing lighting practice The overarching aim of many people involved in lighting research is to change lighting practice so as to deliver the lighting that people desire in a sustainable and economic manner. There are a number of ways to do this. One way is to produce a better product. The growth in the use of solid-state lighting has been driven by the fact that these light sources offer a higher luminous efficacy, a longer life and good colour properties, all at a reasonable price. Another example is the change in outdoor lighting where fully-shielded luminaires have been developed in response to the public concern about light pollution. Another way is to use legislation to ban the use of specific products, usually energy inefficient products. This approach has been used for many years resulting in the removal of electromagnetic ballasts, incandescent lamps and, most recently, halogen lamps, from the market. Yet another way is to change lighting standards or recommendations. This is effective because only the most self-confident lighting designers or electrical contractors are willing to ignore lighting standards and guidance because, to do so, would leave them open to litigation should the design prove to be unsatisfactory. Unfortunately, it is very difficult to get a standard changed even though most quantitative guidance on lighting is prepared by professional bodies. This is because most standards have a defensive screen of vested interests around them. A light source manufacturer who has designed a product range around existing colour metrics will not take kindly to
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a new metric, particularly if some existing products would be downgraded. Similarly, lighting consultants who are familiar with daylight factor may not view having to learn a whole new method of daylight evaluation with much enthusiasm. Moreover, bodies that issue authoritative guidance may have difficulty changing the basis of that guidance if it means admitting that they have been wrong for many years. Despite these defences, standards can be changed. To do this requires a good argument. Such an argument has to address a recognised problem, either a lighting problem or a policy issue related to lighting. Unfortunately, sustainability has not yet reached the critical mass necessary to cause a change in lighting standards. Given that a change in standards is necessary, what is required is a quantitative metric. Quantitative lighting metrics are what save the lighting world from anarchy. Without the lighting recommendations issued by authoritative bodies, and based on such metrics as illuminance on the working plane, illuminance uniformity, colour rendering index and unified glare rating, lighting practice would degenerate into a race to the bottom. Experience over many years has shown that qualitative advice issued by authoritative bodies has little impact. Then, the quantitative metric has to be easily understood, should make a significant difference, and has to be simple to implement in design and in practice. These are all requirements that the researcher should keep in mind if the aim is to change lighting practice. Of all the research reviewed earlier, the quantitative metric most likely to change in the near future is the CIE Colour Rendering Index. An alternative and much more informative system for characterising light source colour properties has already been adopted as a standard in the USA and it is easy to understand[58]. The other attempt to change lighting practice, the removal of illuminances on the task plane as the basis of design and their replacement with the perception-based system of lighting design[30], [31], will take much longer, if ever, because it requires a compete reorientation of how lighting is designed, as well as a new set of metrics. Although it is claimed that the method developed simply follows the approach used by experienced lighting designers, it will require a lot of support for such a dramatic change in metrics to be accepted, as well as some assurance that the change will not lead to an increase in the amount of electricity used for lighting. The wild card in this area is the effect of lighting on health. Very few people care about lighting per se but many care about their health. If it can be shown that exposure to light of a specific spectra and amount is necessary for the health of the whole population, then lighting standards will need to change. At the moment, lighting standards are concerned solely with ensuring visibility without discomfort. These objectives will remain but, if health becomes an additional objective, then lighting standards and lighting practice will have to change. At the moment, research is concentrated on the fundamentals of how light exposure influences the non-imageforming system. Research on application is rather limited and there is no agreement about how to quantify the stimulus delivered to the non-image-forming system so there is a long way to go before we can be sure about the effects of light exposure on human health. However, the potential for changing lighting practice is huge.
4. Conclusion This paper has addressed the current state of lighting research and its future prospects. From the brief review of current research topics, it should be evident that lighting research is indeed active. What is not so clear is whether or not all that activity will lead to any improvements in lighting practice as it affects the bulk of the population. After writing this paper, I have to conclude that the answer is a definite maybe. New technology is waiting to be introduced. Some of this technology has the potential to allow people to choose the form of lighting they like, and to vary it as they desire. The market will decide if such technology is worth having. There is also a lot of new knowledge on the effects of lighting being produced. A lot of this has to do with lighting’s impact on the nonimage-forming system and the consequences for health. There have also been some attempts to explore the impact of lighting on remote effects beyond visibility such as mood, behaviour and cognitive task performance. Much of this is of doubtful value because these remote effects are determined by many factors other than lighting. If the aim is to demonstrate the benefits of lighting other than visibility, it is necessary to focus attention on those aspects of the desired outcome that can be strongly linked to light exposure. As for attempts to change lighting practice, new colour metrics seem certain to be adopted soon, but expecting to completely reorient the purpose of lighting away from task visibility to lighting the space seems unlikely to succeed unless it can be demonstrated that it would make a significant difference to people’s satisfaction with lighting without imposing additional costs. One research area where this is not so is the impact of light exposure on human health. If it can be shown that lighting can have a significant impact on human health, then both lighting standards and lighting practice will have to change, regardless of the cost. This is the research area that is most likely to drive major changes in lighting practice. In conclusion, in my earlier paper[1] I said that for lighting research to flourish it had to move beyond studies of the effects of lighting on visibility and visual discomfort to studies of how lighting influences mood and behaviour. These studies should be done through the “message” that lighting delivers to the perceptual system and health and performance through the effect light has on the non-imageforming system. That has certainly happened. But although lighting research is flourishing, it is not necessarily influential. To become influential, it needs to focus its attention on outcomes that matter to people and the elements of those outcomes on which lighting is known to have a major influence. Further, researchers will have to be determined to overcome the barriers to changing lighting practice. By doing this, lighting research will be seen to change the world for the better, to be an important topic, not an irrelevance.
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The present and future of lighting research
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22. Caicedo D, Li S, Pandharipande A. Smart lighting control with workspace and ceiling sensors. Lighting Research and Technology 2017; 49: 446-460 23. Bergen T, Young R. Fifty years of development of light measurement instrumentation. Lighting Research and Technology 2018: 50; 141-153. 24. Cai H, Chung TM. Improving the quality of high dynamic range images. Lighting Research and Technology 2010; 43: 87-102. 25. Fotios S, Uttley J, Cheal C, Hara N. Using eye-tracking to identify pedestrians’ critical visual tasks. Part 1: Dual task approach. Lighting Research and Technology 2015; 47: 133-148. 26. Villa C, Labayrade R. Validation of an online protocol for assessing the luminous environment. Lighting Research and Technology 2013; 45: 401-420. 27. Rea MS. Value Metrics for Better Lighting. Bellingham,WA: SPIE Press, 2013. 28. Rea MS. The lumen seen in a new light: Making distinction between light, lighting and neuroscience. Lighting Research and Technology 2015; 47: 259-280. 29. Schiekle T. Light and corporate identity: Using lighting for corporate communication. Lighting Research and Technology 2010; 42: 285-295. 30. Cuttle C. A new direction for general lighting practice. Lighting Research and Technology 2013; 45: 22-39. 31. Cuttle C. Lighting Design: A Perception-based Approach. Abingdon, UK: Routledge, 2015. 32. Rea MS, Ouellette MJ. Relative visual performance: A basis for application. Lighting Research and Technology 1991; 23: 133-144.
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33. Fotios S, Yang B, Cheal C. Effects of outdoor lighting on judgements of emotion and gaze direction. Lighting Research and Technology 2015; 47: 301-315.
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34. Mundinger JJ, Houser KW. Adjustable correlated colour temperature for surgical lighting. Lighting Research and Technology. First published 24 November 2017. DOI: 1477153517742682.
12. Rea MS, Figueiro MG. Light as a circadian stimulus for architectural lighting. Lighting Research and Technology 2018; 50: 497-510.
35. Ye M, Zheng SQ, Wang ML, Ronnier Luo M. The effect of dynamic correlated colour temperature changes on alertness and performance. Lighting Research and Technology. First published 14 February 2018. DOI: 1477153518755617.
13. Zhou Z, Wang H, Zhang J, Su J, Ge P. LED chip-on-board package with high colour rendering index and high luminous efficacy. Lighting Research and Technology 2018; 50: 482-488. 14. Tashiro T, Kawanobe S, Kimura-Minoda T, Kohko S, Ishikawa T, Ayama M. Discomfort glare for white LED light sources with different spatial arrangements. Lighting Research and Technology 2015; 47: 316-337. 15. Zhang JP, Bai YF, Zhang X, Chen Wl, Li WB, Cheng GL, Chen X. An optimized model for lifetime prediction of LED-based light bars using luminance degradation method. Lighting Research and Technology 2018; 50: 316-325. 16. Luo MR, Cui G, Georgoula M. Colour difference evaluation for white light sources. Lighting Research and Technology 2015; 47: 360-369. 17. Wei M, Houser KW, David A, Krames MR. Colour gamut size and shape influence colour preference. Lighting Research and Technology 2017; 49: 992-1014. 18. Ma S, Wei M, Liang J, Wang B, Chen Y, Pointer M, Luo MR. Evaluation of whiteness metrics. Lighting Research and Technology 2018; 50: 429-445. 19. Ohno Y. Pratical use and calculation of CCT and Duv. Leukos 2014; 10: 47-55. 20. Dikel EE, Burns GJ, Veitch JA, Mancinci S, Newsham GR. Preferred chromaticity of color-tunable LED lighting. Leukos 2014; 10: 101-115. 21. Wen Y-J, Agogino AM. Control of wireless-networked lighting in open-plan offices. Lighting Research and Technology 2011; 43: 235-248.
36. Eastman CI. Circadian rhythms and bright light recommendations for shift work. Work Stress 1990; 4: 245-260. 37. Figueiro MG, Kalsher M, Steverson BC, Heerwagen J, Kampschroer K, Rea MS. Circadian effective light and is impact on alertness in office workers. Lighting Research and Technology. First published 9 January 2018. DOI: 1477 153517750006. 38. Figueiro MG, Bierman A, Plitnick B, Rea MS. Preliminary evidence that both blue and red light can induce alertness at night. BMC Neuroscience 2009; 10:105. 39. Commission Internationale de l’Eclairage. S009 Photobiological Safety of Lamps and Lamp Systems. Vienna: CIE, 2002. 40. Bullough JD. The blue light hazard: A review. Journal of the Illuminating Engineering Society 2000; 29: 6-14. 41. IEEE Standards association. IEEE Standard 1789-2015 IEEE Recommended Practices for Modulating Current in High Brightness LEDs for Mitigating Health risks to Viewers. Piscataway, NJ: IEEE Standards Association, 2015. 42. Knutsson A. Health disorders of shift workers. Occupational Medicine (London) 2003; 53: 103-108. 43. Smith MR, Fogg LF, Eastman CI. A compromise circadian phase positon for permanent night work improves mood, fatigue and performance. Sleep 2009; 32: 1481-1489.
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44. Golden RN, Gaynes BN, Ekstrom RD, Hamer RM, Jacobsen RM, Suppes T, Wisner KL, Nemeroff CB. The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence. American Journal of Psychiatry 2005; 162: 656-662. 45. Forbes D, Blake CM, Thiessen EJ, Peacock S, Hawranik P. Light therapy for improving cognition, activities of daily living, sleep, challenging behaviour and psychiatric disturbances in dementia. The Cochrane Database of Systematic Reviews 2014; 2: CD003946. 46. Figueiro MG, Plitnick B, Rea MS. Research Note: A self-luminous light table for persons with Alzheimer’s disease. Lighting Research and Technology 2016; 48: 253-259. 47. Scheir GH, Donners M, Geerdinck LM, Vissenberg MCJM, Hanselaser P, Ryckaert WR. A psychophysical model for visual discomfort based on receptive fields. Lighting Research and Technology 2018; 50; 205-217. 48. Uchida T, Ohno Y. Defining the visual adaptation field for mesopic photometry: Effect of surrounding source position on peripheral adaptation. Lighting Research and Technology 2017; 49: 763-773. 49. Principi P, Fioretti R. A comparative life cycle assessment of luminaires for general lighting for the office – compact fluorescent (CFL) vs Light Emitting Diode (LED) – a case study. Journal of Cleaner Production 2014; 83: 96-107. 50. Takhamo L, Halonen L. Life cycle assessment of road lighting luminaires – comparison of light-emitting diode and high-pressure sodium technologies. Journal of Cleaner Production 2015; 93: 234-242. 51. Sleegers BE, Moolenaar NM, Galetzka M, Pruyn A, Sarroukh BE, van der Zanden BM. Lighting affects students’ concentration positively: Findings from three Dutch studies. Lighting Research and Technology 2013; 45: 159-175. 52. Joarder A. Price, A. Impact of daylight illumination on reducing patient length of stay in hospitals after CABG surgery. Lighting Research and Technology 2013; 45, 435-449. 53. Boyce PR, Veitch JA, Newsham GR, Jones CC, Heerwagen J, Myer M, Hunter CM. Lighting quality and office work: Two field simulation experiments. Lighting Research and Technology 2006; 38: 191-223. 54. Hubalek S, Brink M, Schierz, C. Office workers’ daily exposure to light and its influence on sleep quality and mood. Lighting Research and Technology 2010; 42: 33-50. 55. Johansson M, Rosen M, Kuller R. Individual factors influencing the assessment of the outdoor lighting of an urban footpath Lighting Research and Technology 2011; 43: 31-43. 56. Veitch JA, Newsham G.R, Boyce PR, Jones CC. Lighting appraisal, well-being and performance in open-plan offices: A linked mechanism approach. Lighting Research and Technology 2008; 40: 133-151. 57. Wells MM. Office clutter or meaningful personal displays: the role of office personalization in employee and organizational well-being, Journal of Environmental Psychology 2000; 20: 239-255. 58. Illuminating Engineering Society of North America. IES TM-30-18 IES Method for Evaluating Light Source Color Rendition New York: IESNA, 2018.
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Institiúd Teicneolaíochta Átha Cliath Dublin Institute of Technology Dublin School of Architecture College of Engineering & Built Environment Over the next three years the Nearly Zero Energy Buildings (NZEB) Standard will be applied to buildings built for, or rented by, public bodies; then to all new and retrofitted buildings. At the same time technological innovation and other environmental and building performance concerns are creating other needs and opportunities. Dublin School of Architecture has a range of postgraduate and post-apprenticeship programmes that meet these challenges. Practicing architects, technologists and engineers who wish to increase their knowledge and skills in delivering new build and retrofitted buildings to the impending NZEB Standard can join a range of multi-disciplinary, blended online CPD programmes. They may also wish to go further to become industry leaders and specialists in one or more areas of building performance. Applications are being accepted for September 2018. Code
Programme
NFQ level Duration
Fee
DT9771
Postgraduate Certificate in Building 9 Performance (Energy Efficiency in Design)
1 year, part time
F2,500
DT9772
Postgraduate Diploma in Building 9 Performance (Energy Efficiency in Design)
2 years, part time
F5,500
DT9773
MSc in Building Performance 9 Performance (Energy Efficiency in Design)
3 years, part time
F7,500
DT9774
CPD Diploma in NZEB Design Tools
9
1 semester, part time F1,500
CPDEB01
CPD Certificate in NZEB Policy and Technology
9
5 weeks, part time
DT775b
CPD Diploma in NZEB Thermal Bridge
9
2 semesters, part time F1,500
F600
Contact: cormac.allen@dit.ie Site foreman and supervisors working for general builders and subcontractors who wish to engage better with the way information is increasingly delivered or created on site using digital and mobile technologies should attend CPD IT for Site Workers in DIT Bolton Street. Applications are being accepted for January and September 2018. Code
Programme
ARCH6001 CPD IT for Site Workers
NFQ level Duration 6
13 weeks part time
Fee F1,050
Contact: joseph.little@dit.ie For further details see:
http://www.dit.ie/architecture/programmes/
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Institiúd Teicneolaíochta Átha Cliath Dublin Institute of Technology
School of Electrical and Electronic Engineering The School of Electrical and Electronic Engineering, Dublin Institute of Technology (SEEE), is the largest education provider in the electrical and electronic engineering space in Ireland in terms of programme diversity (apprentice to PhD), staff and student numbers. Based in Dublin city centre (Kevin Street) and established since 1887, it prides itself in providing practice-based and professionally-accredited programmes across a variety of full-time and parttime options. The School also focuses on applied research with a strong emphasis on producing useful and novel ideas to help Irish industry compete globally. SEEE research is recognised for its impact and quality, which in many cases is on a par with that of the very best groups internationally.
SEEE Programmes Level 9 (Masters) MSc in Energy Management
DT711 or DT015
ME in Sustainable Electrical Energy Systems
DT704 or DT705
MSc in Electronic and Communications Engineering
DT085 or DT086
Level 8 (Hons) BE in Electrical and Electronic Engineering
DT021
BE in Computer and Communications Engineering
DT081
BSc in Electrical Services and Energy Management
DT035, DT712 or DT018
BSc in Networking Applications and Services
DT080B
Level 7 BEngTech in Electronic and Communications Electrical Services Engineering Engineering
DT008
BEngTech in Electrical and Control Engineering
DT009
Level 7 in Electrical Services Engineering BEngTech BE in Networking Technologies BTech
DT010
For further information on the school contact: School of Electrical and Electronic Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 Tel: + 353 1 402 4617/4650/4575 Email: seee.admin@dit.ie www.seee.dit.ie
DT080A
Enhancing Thermal Mass Performance of Concrete
A case study of energy HIÀFLHQW PHDVXUHV XQGHUWDNHQ LQ DQ LQGXVWULDO IDFLOLW\
Tommy Shannon tommy.shannon@excel-industries.com
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Abstract Energy and facility operational costs are a large part of the
Keywords
overheads of Irish manufacturing and distribution companies.
Accelerated Capital Allowances (ACA); heat recovery;
This paper deals with the design and implementation of
solar thermal; computer control; carbon emissions;
low-carbon technologies and engineering innovations which
virtualised networking; heat pump; programmable
have evolved over recent years, including integration of
logic controller.
network-based programmable logic controllers (PLC), to enhance interconnectivity and control.
Glossary AC
Alternating Current
Recording of the energy consumption of production plant
ACA
Accelerated Capital Allowances
and associated services, including heating and ventilation
CNC
Computer Numerical Control
DC
Direct Current
(HVAC) systems, compressed air systems, water usage/ recovery, power systems, information technology support systems and facilities were undertaken prior to commencing upgrade works.
DHCP Dynamic Host Configuration Protocol EIM
Excel Industries Manufacturing
EN
European Standards
The paper describes how upgrade and retrofit works were
HVAC Heating Ventilation & Air-conditioning
identified following research into the latest equipment and
IT
Information Technology
controls, and these were undertaken as part of three separate
LED
Light Emitting Diode
projects on a phased basis. The initial project concentrated
PLC
Programmable Logic Controller
MIC
Maximum Import Capacity
kWh
Kilo Watt Hour
SEAI
Sustainable Energy Authority of Ireland
SEU
Significant Energy User
TCA
Taxes Consolidation Act
on simple achievable savings in common services for the complete facility, and included compressed air, exterior lighting, water heating and control of the main incoming water and gas services. Completion of the initial phase brought about an ongoing annual saving of 146,600kWh in energy consumption within the facility, reducing direct costs. The reduced energy consumption savings achieved from the first phase were used to part finance capital expenditure on the other two project phases, and combined with the timing of equipment upgrades and periodic maintenance, as in the case of lighting, over a three-year period. The second phase incorporated changes to the main heating and ventilation systems, along with IT infrastructure and centralised control of production processing machines. A major lighting upgrade to LED of the production and warehouse lighting fittings was undertaken as part of the third phase project, with occupancy controls integrated into zoned areas. Continuous monitoring and evaluation over the three years has enabled adjustments to systems, ensuring optimisation of savings and a further annual reduction of over 450,000kWh in energy. The savings have been achieved in a period of expansion in facilities and production, combined with a reduction in the maximum import capacity (MIC). 16
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A case study of energy efficient measures undertaken in an industrial facility
PRINCIPLE ACCESS
H E.S.B. SUBSTATION
6M SLIDING GATE CG001 ENTRANCE ONLY
AC CE SS
2P
LINK CARGO 2 GOODS IN / OUT
Factory 1 PRODUCTION / WAREHOUSE
FD1 VISITOR ENTRANCE
EIM CARGO 3 GOODS IN
PEDESTRIAN ACCESS 1P
CARGO 1 STORES GOODS IN
H
PU BL IC FO OT PA TH
FE2 STAFF ENTRANCE
FE3
FE7
Factory 2 PRODUCTION / MANUFACTURING
FE4 Office STAFF ENTRANCE
6M SLIDING GATE CG003
6M SLIDING GATE CG002 EXIT ONLY
CP1 CUSTOMER ENTRANCE
FE1 STAFF ENTRANCE
PARKING
PEDESTRIAN ACCESS 3P PUBLIC FOOTPATH
PE DE ST RI AN
LOADING
PARKING
FE8
EIM CARGO 4 GOODS IN FIRE EXIT (FE6)
Factory 3 WAREHOUSE / STORES
FD2 STAFF ENTRANCE
6M SLIDING GATE CG004 TRUCKS IN / OUT
LOADING
PARKING H
CARGO 6 STORES GOODS OUT
CARGO 5 STORES GOODS IN
FE5
FE9
FE10
LOADING
LEAF GATES CG005
LOADING RAMP
Dock Leveler & Gate CDL01
Figure 2.1: Layout facilities of the three main buildings.
1. Introduction Irish manufacturing companies have had to adapt and transform to survive in an ever-changing economy, combined with rising energy costs and environmental pressures. Companies that improve their energy efficiency and management can establish real competiveness, making the difference between profit and loss (Turner, W.C. and Doty, S. 2007). Demand for products, both for export and in the Irish marketplace has evolved, as have work-cycle patterns. This paper details the design, implementation and monitoring of retrofitting advances in engineering innovations over a three-year period to reduce energy usage and waste. The facility included a manufacturing division, warehousing and distribution, research and development laboratory and back-end support offices. The benefits of a project approach in developing energy efficient solutions are described in a joint study by the Greenov Partners in How to Develop Energy Efficient Refurbishment on a Large Scale which illustrates a range of technical and software solutions to support reductions in energy consumption. A phased approach was adopted for the implementation and upgrading of energy saving products to ensure the costs were self-
financing, and delivered further capital savings by the accelerated capital allowances for energy efficient equipment under Section 285A TCA 1997 Finance Act 2008. As some of the processes and production systems have changed or adapted over the years and additional mezzanine floors were installed, a revised approach to the services, including lighting designs and space heating, were required. The buildings are over 30 years old and services were designed and installed based on concepts and technologies available at the time. The refurbishment and upgrading works were designed to utilise as much of the original core service systems of wiring and piping and ducting while, at the same time, upgrading equipment types and controls to achieve substantial reductions in energy consumption and waste.
2. Background The facility has three separate buildings with a combined total area of 65,998 sq ft internally. Electricity is provided via a main incoming three-phase 400V supply from a dedicated transformer, and also from a mains incoming natural gas supply for process and space heating. The buildings are linked by a main cargo “in out” building as per Figure 2.1. Most of the operational areas cover two floors and are split as follows:
17
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Facility layout of main three buildings Building 1 Ground floor – Manufacturing First Floor – Pre-packaging manufacturing/component storage. Building 2 Ground floor – Manufacturing Mezzanine floor – Component storage, main canteen, toilets, showroom Office/support – Sales office, locker rooms/wash room, shower facilities. Building 3 Ground floor – Distribution warehouse racking Ground floor – Technical research laboratory First Floor – Distribution warehouse racking Office/support – Admin/finance offices, computer room and facilities.
Figure 3.1: Main incoming distribution board supply.
There is further storage outside the building and sections for cargo loading and truck parking. These areas are enclosed by security fencing and access to the building is via automated gates for security requirements. Because of the different functions in each building, it was decided to undertake a survey of the main loads and operational factors throughout the buildings, evaluating the possible savings that could be implemented and the costings of different engineering solutions. Preparation of a plan based on production/process changes would be the key aspect of a continuous improvement program in the facility to reduce production energy consumption, waste and inefficiencies. The principal energy consumption parts of the facility can be broken down into the following categories: • Heating ventilation and air conditioning; • Compressed air; • Motive power; • Production processing, e.g. welding, thermal seaming, induction heating; • Lighting (internal and external); • Process plant and equipment; • IT infrastructure, networking, communications and control; • Support services, canteens and facilities.
3. Methodology The initial part of the project was to establish energy consumption patterns in the manufacturing and distribution parts of the facility as they covered the larger areas, and then all other areas through metering and recording. To achieve this an energy audit of the facility was conducted to determine where opportunities existed to improve current thermal and electrical energy consumption requirements. The audit identified significant energy users (SEU) of both thermal and electrical energy, and also the daily operational profile mapped against the main energy usage. A Fluke 3 phase 1732 energy logger (Figure 3.2) was installed permanently on the main incoming distribution board supply (Figure 3.1) to monitor the profile of energy consumption on a weekly basis.
Figure 3.2: 3-phase kW recording in main incoming.
Further measurement was also undertaken on sub-distribution boards with other instruments (Figure 3.3) to profile and record the daily operational characteristics (Figure 3.4). Energy recorders were also installed on SEU loads such as compressors, extraction plant, CNC, welding plants and IT servers to enable accurate monitoring and analysis of consumption. Lighting loads were calculated by surveying the number of light fittings in use, both internally and externally, and their load and annual operating hours entered in the lighting section of the SEAI Energy Map spreadsheet toolkit shown on Figure 3.5. Monitoring and recording of the main incoming supply gave a good indication of the load profile over the week and the consumption out of hours. Not only did the energy audit identify areas and opportunities for improvement throughout the manufacturing and warehouse facility, but it also heightened interest and awareness among staff and the management team in each area. Energy bills for gas, electricity and water consumption for the previous three years were analysed to identify overall consumption patterns
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Figure 3.4: Load monitoring and recording
for the facility. This showed the ratio of thermal and electrical energy consumption by month and season. Energy bills were analysed to identify the max demand load monthly, to identify if patterns were evident in the use and cost of energy, and whether consumption patterns varied between winter and summer.
4. Design Concepts
Figure 3.3: Load measurement.
The data collected was collated into a main load survey summary covering the maximum demand as per Figure 4.1. By analysing the audit data, large consumption variations were identified, primarily relating to the compressed air system, night storage load and the
Figure 3.5: SEAI Energy Map Toolkit for Significant Energy users – sample lighting section [3rd April 2016]
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heating ventilation incorporating dust extraction. Research was undertaken into newer and more efficient equipment and how some of the production processes could be modified. A number of different programmable controllers (PLC) were tested for both operational integration and network communications. Siemens Logo 8 was chosen because of its flexibility in dealing with both AC and DC inputs/outputs, and also because of its ability to connect multiple devices on an existing Category 6 cabled, RJ45 computer connection, and to communicate across a standard dynamic host configuration protocol (DHCP) computer network. For a retrofitting project this substantially reduces the physical control cabling as units can be installed as “slaves” around the facility, receiving control instructions from the master unit across the standard IT infrastructure. 4.1 Main installed Load From the information recorded three areas were identified for main projects to be undertaken in stages over a three-year period commencing in March 2015 Figure 4.1 – Main Load Survey Summary Building
Original Load
All
Compressed Air 1 x 37kW Compressor running at base load.
37
1 x 30 kW compressor covering peak load.
30
2 EIM
Process heating
8
All
Water heaters – Canteens/facilities
16.6
All
Exterior lighting Metal Halide/Sun
6.5
2 EIM
Heating Ventilation and Air Conditioning Space Heaters
70
All
Night Storage Heating
72
3
IT Server Infrastructure
10.6
1
Met Fab Production processing equipment 62.4 welding, thermal seaming, induction heating
2 EIM
Production processing equipment Laboratory
2 EIM
EIM Production processing equipment CNC, Edging , Machining
80.6
1
Lighting Production Dispatch Link, Mezzanine and Offices
16.42
2
Lighting EIM Manufacturing and 19.48 Showroom Production/Storage Mezzanine’s, Storage and Canteen
3
Lighting Warehouse and Offices
2
Canteen Water Heating 3 Burko Boilers Max Demand Loading kW:
Total Rating kW
14
Project Phase 1 • • • • •
Compressed air system overhaul and upgrade; Programmable logic control network; Water facility heating and process heating; Exterior lighting; Services control – water, natural gas.
The compressed air system was an important service for all areas but was also one of the highest daily loads. There were also a number of sub-compressors around the building for different processes. It was decided to completely re-design the compressed air system, storage and air drying and to install loading and zone control valves, as well as solenoid control valves, at each machine. By recording and monitoring the air usage profile it was noted that the Base 37kW compressor cycled regularly into idle mode and back to compression, but never off. This was a significant factor for the new design. Project Phase 2 • Heating ventilation and air conditioning; • IT infrastructure, networking, communications and control; • Production processing, e.g. welding, thermal seaming, induction heating; The primary ventilation load consisted of an environmental dust extraction system for the Excel Industries Manufacturing (EIM) building. Redesign of the ducting layout within the building and extraction point controls ensured that the system load was limited to the operational equipment. Further changes involving removal of ducting to areas where production had changed over the years were also planned. Replacing the central IT server system required extensive research into systems and software, ensuring developments in applications used in the facility were covered for the next five years. The existing IT infrastructure contained nine physical servers with a total load of 10.6kW operating around the clock. From research a Dell VORTEX, Virtualised server configuration was chosen as a preferred replacement for the existing server array, enabling multiple “virtualised” to be installed on a single physical unit with significant reduction in the power consumption. Production processing equipment in the metal fabrication area tended to be left switched on, so auxiliary relays were installed and wired back and configured to the main programmable logic controller network to enable controlled switch-off of equipment and auxiliary plant during break-times and on completion of processes. Project Phase 3
18.724 9 462.324kW
• Lighting and controls; • Motive power; • Support services, canteens and facilities. Lighting was identified as an area where substantial improvements could be made by illumination of the workplace as recommended by the EN12464 Standard. The standard specifies the lighting level for the task area, the level of light immediately surrounding by a width of at least 0.5m, and from this the background area at least 3m. Technological advances of lighting types and integrated controls
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provided a number of solutions in areas of direct lighting, or where natural light for daylight linkage could be incorporated. Innovations in high-output fluorescent daylight linkage and LED lighting were also considered. Movement detection was designed into the daily operational requirements based on the standard, ensuring the correct illumination was available for the task. Motive power consumption was improved by the installation of electronic invertors controlling the start-up and running of some of the larger motors. Load recording and upgrading of the central power factor system on the main incoming supply ensured the system was optimised to respond to inductive load variations from the retrofit projects. While a relatively small load for the overall facility, changes to the water heating for locker-room/toilet facilities and canteen were also looked at. The design plan finalised incorporated installing a central solar thermal heated storage tank in each building, complemented with a closed-loop circulated hot water pipe network supplying canteens and facilities, ensuring hot water was always available at the taps during operational times.
Figure 5.2: Base 11kW Kaeser compressor
5. Implementation Project Phase 1 Compressed air system overhaul and upgrade A program of extensive maintenance was initiated, repairing all air leaks on equipment and removing all quick-coupling fittings. Next the complete air system was revamped and zoned into production areas. Solenoids were fitted at each zone (Figure 5.1), controlled from a network-interfaced Siemens programmable logic controller that manages the flow of compressed air to plant and machinery when required. Remote controls were fitted allowing operatives to switch on air to the production zone that they were working in (the control system selects the most efficient mode of compressor cycle operation at a given time). Additional solenoids were also fitted at each machine, isolating air supply when not in use. The existing compressors were replaced with three 11kW compressors working to a higher pressure 8bar (Previously 7.5bar) complemented with three 2000 litre compressed air storage tanks (Figure 5.5).
Figure 5.3: Plant 7.5 bar loading valve
An 11kW Kaeser soft-start unit (Figure 5.2) was installed to run on base-load to the higher output operating pressure of 8bar. The compressor starting-on pressure was reduced to 7.2bar. This gave a new operating differential of 0.8bar, enabling the compressor to switch off more regularly and for longer periods during daily operation. A primary building loading valve set to a maximum output operating pressure of 7.5bar was installed (Figure 5.3). This controlled the output pressure of compressed air to the facility, ensuring safe secondary operating pressure and total isolation at night time, thereby reducing air losses. Two 11kW Ingersoll Rand screw compressors (Figure 5.4) were installed for peak load and in the event of a failure, but because of the efficiencies from reducing air losses and operating at a higher pressure, they have been largely redundant for peak operation. Programmable logic control network
5.1 Facility zone compressed air isolation valves.
Following the selection of Siemens Logo 8 programmable logic controllers (PLC) as the preferable mode of control units, they were installed in the main distribution board and in each power sub
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Figure 5.7: Siemens Logo 8 networked system
Figure 5.4: Peak/back-up 11kW Ingersoll Rand compressors
Figure 5.8: Solar panels for facility and process water heating.
distribution board (Figure 5.6). Each unit was connected to the main computer network, eliminating the requirement to run control cabling. An overview of the Siemens 8 PLC can be seen on the layout diagram Figure 5.7. This system enables multi-application flexibility for the control of compressed air, HVAC, lighting control, etc. and the integration to all existing equipment as part of the retrofit programme. PLC inputs can be AC/DC voltage or current at different voltage levels. Control can be set by calendar, ensuring that equipment is off at weekends, holidays and bank holidays. This system has the flexibility going forward of integrating new equipment and changes in the production process. Figure 5.5: 2,000 litre air storage tanks 8bar.
Water facility heating and process heating Surprisingly, it was discovered that the load from facility water heaters and process heating had grown significantly over the years with the addition of small under-sink heaters ranging from 700W to 1.6kW. Because individually their load capacity was small they had largely gone undetected but the cumulative load was recorded at 24.6kW throughout the facility. Washroom, canteen facilities and locker rooms were re-plumbed to a central tank in each of the three buildings, heated primarily from solar thermal panel (Figure 5.8) and backed up by electric elements on the night rate tariff at a total load of 3.6kW. Process heating for the chemical production section was supplied from a heat pump thermal recovery (Figure 5.9), converting waste heat in the central compressor room. Exterior lighting:
Figure 5.6: Siemens 8 logo PLC at power board.
External lighting was completely revamped, from metal halide fittings consuming between 400W and 250W each to high-output LED
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Figure 5.9: Heat pump for thermal recovery.
Figure 5.10: Main centralised dust extraction system.
fittings varying between 70W and 30W, depending on location. Movement controls were installed in some areas where all-night security lighting was not required, bringing an energy saving of over 70%.
The equipment chosen was on the SEAI Triple E Register, ensuring funding through the Accelerated Capital Allowance (ACA) which is a tax incentive aimed at encouraging companies to invest in energy efficient equipment. The incentive allows eligible companies the opportunity to write off the total purchase value of the equipment in one year against their corporation tax. Capital allowances provisions require companies to own the equipment and use it specifically for
Services control – water, natural gas: Isolation valves controlled for out-of-hours and weekends were installed on the incoming mains water, natural gas to space heating units and urinal flushers in toilets to reduce waste. This alone brought a considerable saving in water consuption of nearly 9,000 litres per month.
Project Phase 2 Heating ventilation and air conditioning: The extraction system ducting was overhauled to adapt to changes over the years in the manufacturing process. Extraction shut-off valves were fitted at each machine to auto-isolate when not in use. The major change in structure was a recirculation damper and ducting back into the building from the filtration output to return air to the building in the winter. This also enabled a damper to divert the air externally in summer mode to cool the manufacturing environment. The motor was also replaced with a 55kW high drive (Figure 5.10) not running at full capacity because of changes in ducting and recirculation of air in normal operation.
Figure 5.11: Vortex virtualised server system.
IT infrastructure, networking, communications and control The nine main physical servers in the computer room running 24/7 all year around were replaced with a single Dell VORTEX virtualised server configuration (Figure 5.11), enabling multiple software virtualised servers to operate from this single physical unit. While this project involved significant capital expenditure and planning, the substantial reduction in operational energy consumption can be seen from Figure 5.12 Vortex UPS Supply showing an operational load of 636W.
Figure 5.12: Vortex UPS supply.
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the purposes of that trade, ensuring that it is still in use at the end of the chargeable period (Revenue Commissioners, Reviewed January 2015). Production processing, e.g. welding, thermal seaming, induction heating The metal fab production area consists of an array of welding plants, induction spot welders, plasma cutters , cnc equipment and ancillary equipment such as guilitines, presses. Overall operations are infrequent but it was noted during the survey that they were left turned on during the day. Simple control interfaces were introduced to auto– shut down or place on standby when not in use.
Project Phase 3 Lighting and controls
Figure 5.13: PLC controlled aisleway LED lighting.
For the implementation reference was taken from the EN12464 Standard to ensure light levels were at an appropriate level for the task and background. Fitting types and controls selected depended on the areas where lights were located, reliability of the solution, and payback cost benefit analysis for each area of application. For the first floor areas of the building and the main EIM manufacturing area high-frequency, high-output fluorescent type fittings with daylight linkage were chosen as these areas had a high level of natural light from roof skylights. The fittings were connected in groups to electronic controllers monitoring light level to predetermined task levels and adjusting the output frequency to the fittings, reducing energy consumption up to 90% depending on the level of natural daylight. The T5 lamp fittings were selected for this application, reducing the maximum power consumption by 60% for the fittings being replaced.
Figure 5.14: Occupancy control of LED lighting.
For the ground floor and lower mezzanine areas the existing fittings were replaced with LED fittings (Figure 5.13) along with an occupancy presence detection (Figure 5.14), ensuring lower energy consumption and fast reaction to movement sensors. Integration of controls with the Siemens Logo 8 programmable controllers ensure only required lights are switched on and at break times, 75% of lights are automatically switched off, so only necessary and walkway lights remain on. In office areas fittings were retrofitted with LED lamps as the optimum option, whereas in larger floor areas high-efficiency LED flat panel fittings were installed to replace the existing fluorescent types. Motive power Variable speed drives were used to replace a number of conventional motor-gearbox drives, mainly on CNC machines, and on cutting and sanding machines. The variable speed drives have reduced operational costs in the woodwork production area by approximately 18% per unit produced while, at the same time, providing better and more accurate means of speed control. The control from the Siemens Logo system ensured that equipment start-ups were not simultaneous, reducing the max demand level at any given time. Support services, canteens and facilities
Figure 5.15: Solar thermal storage tank system.
Burco boilers were replaced with two high-efficient wall-mounted water heaters controlled by the main programmable controllers. This ensured that water was heated at night-rate tarriff and boosted for
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lunch breaks and not left turned on. All other hot water sink, locker and shower facilities were supplied from the newly-installed building solar thermal storage tanks (Figure 5.15) with back-up electrical elements on the night rate tariff.
6. Results Monitoring and measurement of consumption continued after the implementation of each stage of the projects. This enabled continual adjustments of controls and revision of programmes on the Siemens Logo 8 programmable control network. The primary result of the changes was a reduction in the maximum available demand by 195.65kW. Further annual operational reductions and savings achieved from each project are summarised below. The summary breakdown between the original load and post-retrofit for Project Phase 1 can be seen in Figure 6.1. Figure 6.1 – Energy consumption Project 1 monitored pre- and post- retrofit Project Phase 1:
Figure 6.2 – Energy consumption Project 2 monitored pre- and post- retrofit Project Phase 2:
Original Total kWh
New Total kWh
Heating Ventilation and Air Conditioning
142800
73440
Night Storage Heating
120960
36000
IT Infrastructure – Servers
96602
6115.2
Production processing e.g. welding, thermal seaming, induction heating
63648
32130
Production processing equipment Laboratory
28560
12240
EIM Production processing equipment CNC, Edging , Machining
82212
43758
kWh Total:
534782
203683
Figure 6.3 – Energy consumption Project 3 monitored pre- and post- retrofit
Original Total kWh
New Total kWh
Compressed air system overhaul and upgrade
98729
5455
Project Phase 3:
Water facility heating and process heating
16320
1020
Lighting and Controls
Process heating
21165
918
Exterior lighting
21249
3374
kWh Total:
157463
10767
Maintenance of the air system to minimise leaks and increasing the compressed air back-end air pressure by 0.5bar accompanied by 6,000 litres of primary storage enabled significant operational energy savings. Figure 6.2 shows the energy totals for Project 2 monitored originally and post retrofit. Changes to the main extraction system contributed to lower demands on the main drive motor, reducing operational costs. Changes to control of the night storage heating system and switching off at weekends/bank holidays added to the energy savings. In three areas of the facility (canteen, toilets and locker rooms), the storage heaters were replaced with ceiling panel induction space heating devices controlled to heat during the periods of occupancy. Combined with reductions from the virtualised server system, and production machine control, Project 2 accounted for nearly 50% of the overall savings but nearly 70% in the capital investment costs to implement.
Original Total kWh
New Total kWh
Blg 1 Production Dispatch Link, Mezzanine and Offices
50738
9753.96
Blg 2 Lighting EIM Manufacturing and Showroom
60193
6426
Blg 3 Lighting Warehouse and Offices
57857
7063.5
Support services, canteens and facilities
5508
1322
534782
203683
kWh Total:
while not as significant a capital expenditure as other equipment, required considerable resources in time to install. Savings from each project are summarised in the comparison graph Figure 6.4.
Figure 6.3 shows the energy totals for Project 3 monitored originally and post retrofit following a major upgrade primarily of the lighting: While lighting and controls were identified initially as an area where significant savings could be made, they were left to the third project. This was because the installation of a network of Siemens Logo 8 programmable logic controllers linked to the new IT Virtualised server system had to be undertaken. Replacement of the lighting system,
Figure 6.4: Annual total reductions from each project are shown against original operation.
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air system, required relatively small investments for the large energy reductions achieved. Reduced ongoing maintenance costs and longer operational life from equipment such as LED fittings, optimising occupancy controls, reduced CO2 emissions, changes in kWh from day to night rates and accelerated capital allowances are other factors that will affect the actual pay-back.
Figure 6.5: Summary of total annual savings from each project.
The implementation of low-carbon technologies and engineering innovations were carried out in a period of increased production and installation of additional production equipment to meet production requirements. Cumulative reductions from each project have brought significant savings to daily operational energy consumption and costs with an annual reduction at year three of 627,525 kWh of energy. The annual savings going forward from each project can be seen from Figure 6.5. Reductions in energy consumption as a consequence reduced the carbon emissions from the facility. Using the carbon footprint calculator from Energia, the retrofit works implemented in the three projects have reduced the CO2 emissions to the environment by 333,843 Kg.
7. Conclusions Significant advances in electronic equipment and controls for motor drives, lighting, communications and information technology equipment are enabling significant savings in the cost base of energy and a reduction in carbon emissions for businesses. A balance has to be struck when retrofitting facilities covering large floor areas between the cost of the equipment and installation works against the ongoing savings. For this facility, having undertaken the initial energy audit, it was decided to undertake the energy savings and retrofit through a phased approach. Upgrading the compressed air system was selected as one of the first projects as it did not require significant resources in labour to implement. The savings made through the initial project were used to complement the costs of project implementation. After three years there is a total annual reduction 627,525kWh for the facility and a further reduction of 333,843Kg of CO2 waste. Other financial savings have been achieved by the reduction of the maximum import capacity (MIC), enabling savings on monthly maximum demand billing charges. Capital investment of energy efficient products from the SEAI Triple E Register accounted for a further write-back of F36,917 against the corporation tax. However, the final real pay-back across all projects over the three years is difficult to calculate as some of the measures, for example the replacing of servers computers required large capital investment, whereas other measures such as changes to the heating and ventilation systems and extraction, and upgrades to main compressed
26
There are plenty of new technologies available in the marketplace for improved performance and efficiency of equipment. These are ideal and easily designed into new installations. However, retrofitting of older installations, especially where processes and applications have changed, require more thought at the design and integration to ensure that the implementation of technological advances have a pay-back and positive impact for the environment. It is important post implementation stage of any system to continue with regular monitoring and recording, and with making adjustments to controls and equipment, to ensure optimisation of operation and savings.
References David McCulloch, WSGS 2003, “Improving Compressed Air System Performance: A Sourcebook for Industry”, Sourcebook for Industry., U.S. Department of Energy., Energy Efficiency and Renewable Energy. DOE/GO-102003-1822, US DOE, California. Day, A. R., Ratcliffe, M. S. & Shepard, K. J. 2003. Heating Systems, Plant and Control, Oxford, Blackwell Publishing. Department of Finance Accelerated Capital Allowances for Energy-Efficient Equipment [Section 285A TCA 1997] Finance Act 2008. Shengwei Wang. 2010. Intelligent Buildings and Building Automation: published by Spon Press of the Taylor & Francis Group,2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN. Turner, W.C. and Doty, S. (2007) Energy Management Handbook, 6th edition, Oklahoma: The Fairmount Press. SEAI Accelerated Capital Allowance (ACA) – Lighting 2016. Available: (http:// www.seai.ie/your_business/accelerated_capital_allowance) [12th March 2016] How to Develop Energy Efficient Refurbishment on a Large Scale. Available:http:// www.codema.ie/images/uploads/docs/Greenov_Report_How_to_Develop_Energy_ Efficient_Refurbishment_on_a_Large_Scale.pdf [20th March 2016]. Sustainable Energy Ireland – SME-Guide-to-Energy-Efficiency. Available: https:// www.seai.ie/resources/publications/SME-Guide-to-Energy-Efficiency [3rd April 2016]. Sustainable Energy Ireland SEAI tools and calculators. Available: https://www.seai. ie/resources/tools/Lighting-Replacement -Calculator.xlsx https://www.energia.ie/ business/energy-efficiency/carbon-calculator [2rd April 2018]. Energia – Calculate your carbon emissions. Available: https://www.energia.ie/ business/energy-efficiency/carbon-calculator [2rd April 2018].
Institiúd Teicneolaíochta Átha Cliath Dublin Institute of Technology School of Multidisciplinary Technologies College of Engineering & Built Environment The School of Multidisciplinary Technologies provides modules and programmes, at undergraduate and postgraduate levels, which link engineering and built environment disciplines for the design and operation of healthy, low-energy buildings and infrastructure for a modern sustainable world. These full-time and part-time courses are founded on a research base and promote multidisciplinary themes across the DIT and with external partners. Themes include energy, sustainability, engineering computing (applied technology), building information modelling and management (BIM), and educational research.
Undergraduate Programmes Bachelor of Engineering (Hons) Engineering (General Entry)
Full Time
DT066
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Full Time
DT097
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Part Time
DT9876
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Part Time
DT9876
Part Time
DT9876
Check out our video “DIT Engineering General Entry” on YouTube.
Postgraduate Programmes
Check out our video “BIM@DIT Promotion” on YouTube.
Research Programmes PhD and MPhil opportunities in areas such as Lighting, Energy Management, FT/PT BIM, collaborative Digital Construction, and Analytics/Computation/ Critical Digital Literacy for Engineering and Built Environment Applications
Contact School
CPD By successfully completing modules from our Postgraduate Suite in areas such as BIM and Applied Computing you can upskill in emerging aresa and progress your career through the award of standalone CPD certificates or through the accumulation of credits into postgraduate awards. Review our available modules on: Review our available modules on: www.dit.ie/bim and www.dit.ie/multidisciplinarytechnologies
Please contact us if you have any queries about our programmes, research, or other activities. School Administrator: Jane Cullen. Tel: 01 – 402 4014. email: multidisciplinaryadm@dit.ie DIT Multi-Discp 2018.indd 1
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Enhancing Thermal Mass Performance of Concrete
A matched pair of test houses with synthetic occupants to investigate summertime overheating
Ben M. Roberts
David Allinson
Kevin J. Lomas
LOUGHBOROUGH UNIVERSITY b.m.roberts@lboro.ac.uk
LOUGHBOROUGH UNIVERSITY d.allinson@lboro.ac.uk
LOUGHBOROUGH UNIVERSITY k.j.lomas@lboro.ac.uk
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Abstract
1. Introduction
Summertime overheating is increasingly prevalent in both
Summertime overheating of dwellings is a growing health problem in the UK, with reports of dwellings experiencing high internal temperatures in the present climate[1]. The risk of overheating may be getting worse due to a warming climate with increasingly extreme weather events such as heatwaves; higher levels of home insulation and airtightness that reduce the rate of heat loss generated by internal and solar heat gains; an increasingly urbanised population exposed to urban heat islands, with potentially fewer adaptive opportunities; a reluctance to ventilate by leaving windows open due to pollution, noise and security risk; and an ageing population less able to regulate their body temperature and more likely to be at home at high risk periods (mid-afternoon)[2].
new and existing UK dwellings. High internal temperatures can be dangerous to vulnerable occupants, disrupt sleep and cause thermal discomfort. The mitigation or exacerbation of overheating through simple occupant interventions like window opening and blind use needs better understanding if homes are to be comfortable and safe in summer without the use of air conditioning. This paper describes the adaptation of two adjoining, semi-detached houses to create a matched pair of test houses for full-scale, side-by-side summertime overheating experiments under real weather conditions. Synthetic occupancy was installed to allow dynamic remote control of actuated windows, motorised curtains, automated internal doors and internal heat gains. The houses were instrumented with calibrated sensors to measure the internal and external environment. These instrumented, matched pair homes have also been used to accurately quantify the effects on energy demand, internal temperatures and air quality of refurbishment strategies, occupant behaviour, and different heating, cooling and ventilation technologies.
Keywords Overheating; test houses; experiments; synthetic occupancy; measurement.
High indoor temperatures are a concern for occupant health. Studies are more actively focusing on overheating in dwellings[1], [3], [4], [5], [6], [7], [8], [9], [10] . The bias is towards modelling studies, which are faster and cheaper than monitoring. Detailed monitoring is however needed to understand the effect of occupant behaviour on overheating and so to produce better models and validate existing ones. A study by Jones et al.[11], for example, calls for more monitoring work after observing that two similar homes had very different summertime temperatures, which was attributed to differing occupant behaviour. One method would be to compare two identical houses in the same location whilst occupant behaviour is changed in a measurable and repeatable way. This paper describes how two adjoining semi-detached houses were adapted and modified into a fully instrumented matched pair test facility for studying the impact of occupant behaviour on indoor temperatures in summer. The houses, which had been used in a previous study[12], were refurbished in the same way and had automatic controls fitted to the windows, curtains, blinds, and internal doors with schedulable internal heat gains implemented in each room. Tests ensured the heat loss and airtightness of the houses was similar. Experiments using the test houses were conducted in summer 2017 and the results will be presented in a future paper.
2. Test houses 2.1 Built form, layout and construction The test houses comprise a matched pair of two adjoining unoccupied semi-detached two-storey houses (Figure 1 and Figure 2), with a mirrored floor plan (Figure 3). They are naturally ventilated (free running) with no mechanical ventilation. Window sizes and opening areas are identical in each house. Each house has three bedrooms, (UK mean 2.8[13]), a total floor area of 85.4 m2, (UK mean 94 m2)[13], and a total volume of 209.2 m3. Semi-detached homes are the most prevalent housing type in the UK[13]. In common with 16.7% of the UK housing stock[13], the test houses were built in the 1930s in a manner typical of the era, with uninsulated brick cavity walls and uninsulated suspended timber floors ventilated below by air bricks, both elements verified via borescope examination (see Table 1, next page, for assumed U-values).
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A matched pair of test houses with synthetic occupants to investigate summertime overheating
Figure 1. Loughborough matched pair test houses viewed from the front.
Figure 2. Loughborough matched pair test houses viewed from the rear.
The houses are well matched, having been maintained in the same way by Loughborough University for many years and simultaneously upgraded during the summer of 2016 with 300 mm of loft insulation and double-glazed windows and doors (Table 1). For full details of all the refurbishments’ works see Roberts et al.[14]. The test houses compare to the UK housing stock where nationally 30.5% have
uninsulated cavity walls, 38.5% similar levels of loft insulation and 80.8% are fully double glazed[13].
Each house is entered on the south side into an entrance hallway with stairs leading to the upper floor; a kitchen to the north; with a separate dining room and living room against the party wall to the north and south of the house respectively. The living rooms feature a
Table 1 – Summary of construction elements, areas and estimated U-values from SAP[15] and calculated U-values from glazing and insulation manufacturer.
a
External walls
Uninsulated brick cavity
1.6
89.2
Internal partition walls
Solid brick covered with gypsum plaster
2.1
53.9
Party wall
Uninsulated brick cavity covered with gypsum plaster
0.5
42.2
Bathroom
Bathroom
3.8 m² / 9.1 m³
3.8 m² / 9.1 m³
Ground floor (except kitchen)
Suspended timber (uninsulated)
0.8
37.6
Ground floors (kitchen)
Solid concrete (uninsulated)
0.7
5.7
Windows (north and south)
uPVC double glazing
1.4
20.3
Windows covered (east and west)
uPVC double glazing with aluminium foil on glazing and 50 mm PIR foil-backed insulation board inserted into the frame.
0.46
2.7
c
External doors
uPVC with double glazing
1.4
5.5
c
External door glazing covered (east and west)
uPVC double glazing with 50 mm PIR foil-backed insulation board over glazing only.
0.46
0.51
Down
WC 0.8 m² / 1.9 m³
Rear Bedroom
Rear Bedroom
14.4 m² / 34.6 m³
14.4 m² / 34.6 m³
WC 0.8 m² / 1.9 m³
Front Bedroom
Front Bedroom
14 m² / 33.6 m³
14 m² / 33.6 m³
Down
0.16
Landing 5.6 m² / 13.4 m³
300 mm fibreglass, pitched with clay tiles over vapour-permeable membrane b
45.6
FIRST FLOOR
Landing 5.6 m² / 13.4 m³
Roof
U-value Area (m2) (W/m2K)
Single Bedroom
Single Bedroom
4.2 m² / 10 m³
4.2 m² / 10 m³
GROUND FLOOR c Kitchen 5.7 m² / 14.3 m³
Dining Room
Dining Room
14.2 m² / 35.5 m³
14.2 m² / 35.5 m³
Living Room
Living Room
13.6 m² / 34 m³
13.6 m² / 34 m³ Up
a. Horizontal area (not pitched) b. Measured at internal wall surface c. Total area including frames
Kitchen 5.7 m² / 14.3 m³
Up
Building element Description
The houses are in a suburban residential area of Loughborough, UK (52.771071° N, 1.224264° W). The front of the dwellings face southsoutheast (160°) towards a front garden and a road, the rear of the properties faces north to a large back garden. There are neighbouring houses of similar roof heights to the east and west.
Hall
Hall
9.1 m² / 22.8 m³
9.1 m² / 22.8 m³
West House
East House
Figure 3. Floor plans of test houses.
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Figure 4. Application of foil and insulation to landing windows to reduce east/west solar gain.
Figure 5. Fireplace vents sealed with aluminium tape to ensure uniformity between houses.
bay window and the dining rooms a glazed door to the garden. On the upper floor the rooms off the landing include a small WC and a separate bathroom on the north side. The three bedrooms comprise a small box-room to the south and two large bedrooms to the north and south over the dining and living rooms. The south-facing double bedroom also features a bay window (Figure 3). The side-by-side adjoining houses will inevitably influence each other. One house will shade the other at points throughout the day. One house will shelter the other from the wind. There will be some heat transfer between the two houses via the party wall. However, the party wall is of cavity construction and unsealed at the top. This is likely to reduce the heat transfer between dwellings, while providing another heat loss path. In summer there is a small difference between the inside and outdoor air temperature. In the winter heating season there is usually a greater difference. During winter testing the party wall will be a greater source of heat loss than in summer. 2.2 Modifications for testing Modifications were carried out to the houses to ensure that the thermal performance was the same. The primary concern was they would receive different solar gains through the side windows: east facing windows in one house and the west facing in the other. To limit this difference, aluminium foil was taped to the glass on the inside of each of the side windows and 50 mm polyisocyanurate insulation boards, with a low emissivity foil-facing, were taped across the entire opening (Figure 4). The U-value of the blocked windows is lower than the external walls (Table 1). The chimney breasts in the living and dining rooms had been bricked up at some unspecified point in the past and fitted with vents. The vents differed in sizes between houses so were sealed using aluminium tape (Figure 5). Air vents in the external walls of the upstairs bedrooms were also sealed with aluminium tape. Sub-floor airbricks were left unblocked.
3. Comparing the thermal performance of the test houses Thermal performance and airtightness testing was carried out to confirm that the two test houses were closely matched. A co-heating test was used to measure the heat transfer coefficient and a series of blower door tests to measure the airtightness. All performance tests were conducted after the double-glazed windows and doors, loft insulation and new roof had been installed and after the modification work of blocking east and west facing windows and chimney/room vents had been carried out. 3.1 Co-heating test The co-heating test measures the heat transfer coefficient (HTC) of a building. The HTC has units of Watts per Kelvin (W/K) and combines transmission and ventilation heat loss[16]. Co-heating tests were conducted simultaneously in both houses from 7 December to 31 December 2016 (25 days) following the methodology set out by Johnston et al.[17]. Bauwens et al.[16] achieved satisfactory thermal characterisation results in two weeks, so 25 days was deemed sufficient. During the test, the houses were heated to a constant 25°C air temperature using electric fan heaters in every room (Figure 6). The heaters were controlled using a thermostat located on a tripod in the volumetric centre of the room and shielded from solar radiation using thin foil-covered insulation. Floor-mounted fans ensured mixing and circulation of air in and between zones. Heaters faced away from walls to heat room air, not the building fabric. Fans faced away from external walls to avoid increasing the surface heat transfer coefficient[18]. Internal doors, blinds and curtains were fully open. External doors, windows and trickle vents remained shut throughout testing. No occupancy was simulated, and the gas central heating was turned off.
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A matched pair of test houses with synthetic occupants to investigate summertime overheating
Figure 7. Qualitative air leakage testing using smoke sticks.
Table 3 – Mean q50 results from blower door tests West house q50 (m3/h/m2 @ 50Pa)
East house q50 (m3/h/m2 @ 50Pa)
Difference
14.7
14.9
1.4%
house. More tests were carried out in the west house due to research associated with Roberts et al.[14]. The airtightness was measured by fan depressurisation using a Model 3 Minneapolis blower door located in the rear door. This method was selected due to its speed and simplicity and was found to produce consistent results in a variety of weather conditions[14]. Tests were carried out in accordance with the ATTMA protocol[21]: all external doors and windows were closed and internal doors propped open; water traps in sinks and baths were filled with water and wall vents and fireplace vents were sealed with aluminium tape; gas central heating was turned off during testing; trickle vents were closed.
Figure 6. Co-heating equipment deployed in each room.
Table 2 – Results from co-heating tests West house (W/K)
East house (W/K)
Difference
223
216
5.6%
Power measuring plugs (Figure 14, see p35) recorded electrical heat input from all electrical devices. U-type thermistors placed on shielded tripods measured indoor air temperature at one-minute intervals. Another shielded thermistor measured outdoor air temperature on the north side of the house. All thermistors were calibrated at five points using a water bath and calibrated thermometer. Global horizontal solar radiation data was sourced from Sutton Bonington Weather Station 5.38 km from the test houses[19]. Prior to the test starting the houses were pre-heated to 25°C using the electric heaters for three days to warm the thermal mass. During this pretest phase, the thermostatic controllers were adjusted to achieve the same temperature in each room as recorded by calibrated thermistors. Data was analysed using the Siviour linear regression method[18]. The results for the two houses (Table 2) were within the uncertainty of the co-heating test method of ±8-10%[18], [20]. This demonstrates that the houses are thermally matched. 3.2 Blower door test Blower door airtightness testing was conducted by the same operator on 12 separate days between 4 January 2017 and 15 March 2017. A total of 34 tests were carried out in the west house and 16 in the east
The tests showed that the houses have similar airtightness with only 1.4% difference (Table 3). The mean q50 value of 34 tests in the west house was 14.7 m3/h/m2 with a standard deviation of 0.26 m3/h/m2 and a standard error of 0.05 m3/h/m2. The mean q50 value for 16 tests in the east house was 14.9 m3/h/m2 with a standard deviation of 0.4 m3/h/m2 and a standard error of 0.09 m3/h/m2. The higher standard error in the east house is due to the smaller sample size. The repeatability of these blower door tests is discussed in Roberts et al.[14]. At points during testing smoke sticks were used to identify air leakage paths. The leakage paths in both houses were similar: under window ledges, through gaps in skirting boards, around plumbing and electricity services, at the edge of the suspended timber floor, and into the loft hatch (Figure 7). The windows were well sealed but there was some leakage through closed trickle vents.
4. Synthetic occupancy To replicate real people, synthetic occupancy was installed in both houses to control window opening, blind and curtain use, internal door opening and internal heat gains. A wireless smart home controller (Figure 8) was used to set time schedules for each device or to respond to triggers, such as temperature thresholds. Synthetic occupancy provides the ability to define precise behaviours that are performed at specific times: producing heat from metabolic processes and using appliances; and opening and closing doors, windows, curtains and blinds. Synthetic occupants can do these things with far less variability than real occupants, which has both positive and negative implications for research. There is a high degree
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Figure 8. Left – Lightbulbs connected to smart plugs. Right – smart home controller used to control all synthetic occupancy devices in the test houses.
Figure 10. Left – wireless temperature sensor which relayed room air temperature data to the controller. Right – wireless receiver embedded behind each window switch which controlled window opening.
of certainty that the behaviours are being performed at specific times, but synthetic occupants can never truly represent the inherent psychological, sociological, cultural and irrational drivers of human behaviour. Internal heat gains, to represent people and appliances, were generated using electric lightbulbs connected to smart plugs (Figure 8). Lightbulbs were sized to produce specific heat gains in each location and were the same in both houses. Chain actuators were installed to open and close windows. For security reasons, and to prevent rain ingress, only top-hung windows were actuated (Figure 9). Larger side-hung windows may provide greater ventilation rates, but people may be reluctant to use them for security reasons and their use was not practical in unoccupied test houses, which are unattended for long periods. All rooms had at least one actuated window. Every actuated window was controlled independently, with signals from the smart home controller via a dedicated wireless receiver (Figure 10). Window opening can respond reactively to temperature and occupancy stimuli or statically to fixed schedules independent of temperature. For reactive window opening, windows opened when specific air temperature thresholds were exceeded, and the room was deemed to be occupied. Windows closed when the temperature fell below a specified value or the room became unoccupied. Internal temperature data was transmitted to the smart home controller from room-specific sensors placed in the centre of each room on the tripod under a radiation shield (Figure 10). A window control program was written using “Apache Groovy” programming language which used conditional statements to perform window opening actions based on true or false conditions. Namely “if” the room indoor air temperature exceeded a set value and the room was scheduled to be occupied “then” a window open signal was sent by the controller to open the window in that room, “else”
Figure 11. Automated curtains and blinds used in the test houses.
a close signal was sent. For windows to open both temperature and occupancy requirements must be satisfied (above threshold and occupied). However, windows closed if either the room temperature fell below the set threshold or the room became occupied. Occupancy schedules were inputted into the control program along with window open temperature thresholds. Curtains were controlled via motorised toothed-rails and blinds via a motorised roller. Curtains with a curved rail were used in the living room and front bedroom to fit the bay window. Curtains on a straight rail were used in the dining room, front single bedroom and rear bedroom. Roller blinds were used in the kitchen and bathroom (Figure 11). Each window covering was connected to a wireless receiver and programmed to open or close based on time of day via the smart home controller. Chain actuators were used on internal doors, controlled by a wireless receiver connected to the smart controller (Figure 12). Spring closers were used on each door along with a flexible connection between
Figure 9. Windows controlled by chain actuators.
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Figure 12. Internal doors controlled by a chain actuator.
recorded to a cloud storage database whenever a change in state occurred (Figure 13). Metering plugs measured the electricity consumed by every internal heat gain and allowed detection of failed heat emitters (Figure 14). Internet connected cameras, with pan and tilt control, were used to remotely view the rooms and check for correct internal door and curtain operation (Figure 15). Figure 13. Contact sensor recording window opening.
It was important to continuously monitor the performance of the synthetic occupancy devices to ensure that what was programmed to happen, did happen. Synthetic occupancy monitoring devices were chosen to be accessed remotely so as not to disrupt the tests. Contact sensors were placed on all opening windows with open/close status recorded to a cloud storage database whenever a change in state occurred (Figure 13). Metering plugs measured the electricity consumed by every internal heat gain and allowed detection of failed heat emitters (Figure 14). Internet connected cameras, with pan and tilt control, were used to remotely view the rooms and check for correct internal door and curtain operation (Figure 15).
5. Monitoring temperatures, comfort and weather Figure 14. Electricity meter logger plug.
Figure 15. Internet connected camera and camera output.
the chain and the door. This was so that doors could always be opened, even when actuated closed, preventing trapping. It was important to continuously monitor the performance of the synthetic occupancy devices to ensure that what was programmed to happen, did happen. Synthetic occupancy monitoring devices were chosen to be accessed remotely so as not to disrupt the tests. Contact sensors were placed on all opening windows with open/close status
Internal dry bulb air temperature was measured at one-minute intervals using U-type thermistors (¹0.2°C) wired into a datalogger, calibrated using a temperature-controlled water bath and calibrated thermometer. The thermistor was hung on a tripod at a height of 1.1 m and protected from incoming solar radiation using a shield made of foil-backed bubble-wrap held in a cylinder with aluminium tape (Figure 16). Care was taken to avoid the thermistor touching the tripod or radiation shield. One thermistor was placed on a tripod in the centre of every room, including the hall. In the living room and double bedrooms, in addition to the central thermistor, three shielded U-type thermistors were placed at 0.1 m, 0.6 m and 1.1 m (Figure 17) in the assumed position of a seating area or bed. Operative temperature was measured in every room at one-minute intervals using a 40 mm black globe[22], [23] attached to a calibrated U-type thermistor wired into a datalogger. In the living room and large bedrooms, black globes were mounted at 0.6 m from the oor
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Figure 16. Left – shielded tripod covering wired U-type thermistor. Middle – 40 mm black globe on a U-type thermistor taped to a tripod. Right – battery powered T-type thermocouple.
in the assumed position of a seating area or bed. In all other rooms the black globes were placed centrally in the room at 1.1 m from the floor, attached to a different tripod than used for the air temperature measurements, to avoid obstruction from the radiant shield (Figure 16). Care was taken to avoid direct sunlight falling on the black globe. Additional battery-powered T-type thermocouple loggers with 40 mm black globes (±0.2°C) (Figure 16) were positioned on each tripod as a backup should wired thermistors fail. In the living room of each house, operative temperature data were collected at thermal comfort stations sited at the assumed position of a seating area. Thermal comfort stations comprised measurements of dry bulb temperature, omni-directional air velocity and direction at three heights (0.1, 0.6 and 1.1 m from floor), and a direct measurement of operative temperature using a grey ellipsoid probe (±0.2°C) (Figure 17: Left). The operative probe was angled 30° from vertical at 0.6 m from the floor to represent a seated person (Figure 17: Right). Thermal comfort station sensors logged at ten-minute intervals to allow adequate sensor response time.
The ellipsoidal operative probes were calibrated in a climate chamber which itself had been calibrated (Figure 18). A U-type thermistor, calibrated in a water bath against a calibrated thermometer, was placed inside the climate chamber as a secondary comparison to ensure the chamber was at the correct temperature.
Figure 17. Left – thermal comfort station. Right – Ellipsoidal operative probe.
External dry-bulb air temperature was measured using a calibrated U-type thermistor connected to the indoor data logger. The external thermistor was shielded by a naturally-aspirated radiation shield. One external thermistor was used per house, as a precaution should one fail. Wind speed and direction was sourced from the University weather station, 1km from the test houses. The same weather station also provided global horizontal solar radiation data. There may be small differences between the weather at the test houses and weather station due to the differing topography and sheltering or canyoning effects of surrounding buildings and trees.
Figure 19. Naturally-aspirated radiation shield for external air temperature monitoring.
Figure 18. Calibrating operative probes in a climate chamber using a previously calibrated U-type thermistor.
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6. Proposed experimental programme The houses will be used to investigate the mitigation of summertime overheating through various interventions such as dynamic ventilation in response to specific indoor temperatures, night ventilation and the use of internal blinds. The experimental programme will comprise side-by-side paired tests with different occupant behaviours enacted in each house. This gives the ability to make direct comparisons between two sets of behaviours and analyse their effects on internal temperature, thermal comfort and compliance with overheating criteria. The data gathered will help build better, more accurate models of overheating risk in UK homes and provide a better understanding of the effect of occupant behaviour on internal temperatures during heatwaves.
Centre for Doctoral Research in Energy Demand (grant EP/L01517X/1). Loughborough University is acknowledged for funding the continued maintenance of the test houses and providing 24-hour security.
This unique facility can be used to directly compare the impact of occupant behaviours, fabric upgrades, heating/cooling systems and their controls in any season. It is being used in a wide range of research projects.
7. Conclusion Summertime overheating in UK dwellings is a growing problem. The effect of occupant behaviour on overheating is expected to be significant, yet is poorly understood. This paper has described a synthetically-occupied, matched pair of test houses prepared for conducting a range of overheating experiments under UK summer weather conditions. They have the same construction, having been built at the same time and renovated in tandem since then. The houses were modified and tested to ensure that they were matched in their thermal performance. They were also modified to minimise the effect of unequal solar gains. The co-heating test showed a 5.6% difference in heat transfer coefficients between houses. Blower door tests demonstrated similar airtightness (1.4% difference) and qualitative smoke-stick analysis identified similar air leakage paths. A range of devices were installed to replicate the behaviour of human occupants and sensors were installed to measure the internal and external conditions. This test facility provides the opportunity to enact different occupant behaviours in nominally identical houses and directly compare the differences in internal temperatures and thermal comfort under the same weather conditions. Future planned work will identify how occupants can reduce overheating risk. These matched pair homes can be used to accurately quantify the effects on energy demand, internal temperatures and air quality of different occupant behaviours, heating, cooling and ventilation technologies. Note: This paper is based on Roberts et al.[24] to which additions and amendments were made following peer review for this journal. Acknowledgements This research was made possible by Engineering and Physical Sciences Research Council (EPSRC) support for the London-Loughborough
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References [1]
A. Beizaee, K. J. Lomas and S. K. Firth, “National survey of summertime temperatures and overheating risk in English homes,” Building and Environment, vol. 65, pp. 1-7, 2013.
[2]
K. J. Lomas and S. M. Porritt, “Overheating in buildings: lessons from research.,” Building Research & Information, vol. 45, no. 1-2, pp. 1-18, 2017.
[19] The British Atmospheric Data Centre, “Extract UK Station Data – The CEDA Web Processing Service (WPS),” 2017. [Online]. Available: http://ceda-wps2.badc.rl.ac.uk/view/proc?proc_id=ExtractUKStationData. [Accessed 15 January 2017].
[3]
R. Gupta and M. Gregg, “Using UK climate change projections to adapt existing English homes for a warming climate,” Building and Environment, vol. 55, pp. 20-42, 2012.
[20] R. Jack, D. Loveday, D. Allinson and K. J. Lomas, “First evidence for the reliability of building co-heating tests,” Building Research & Information, pp. 1-19, 2017.
[4]
K. J. Lomas and T. Kane, “Summertime temperatures and thermal comfort in UK homes,” Building Research & Information, vol. 41, no. 3, pp. 259-280, 2013.
[21] ATTMA, Technical Standard L1: measuring air permeability in the envelopes of dwellings, Buckinghamshire: The Air Tightness Testing & Measurement Association, 2016.
[5]
A. Mavrogianni, P. Wilkinson, M. Davies, P. Biddulph and E. Oikonomou, “Building characteristics as determinants of propensity to high indoor summer temperatures in London dwellings.,” Building and Environment, vol. 55, pp. 117-130, 2012.
[22] CIBSE, “Environmental Design: Guide A,” Chartered Institute of Building Services Engineers, 2006.
[6]
A. Mavrogianni, M. Davies, J. Taylor, Z. Chalabi, P. Biddulph, E. Oikonomou, P. Das and B. Jones, “The impact of occupancy patterns, occupantcontrolled ventilation and shading on indoor overheating risk in domestic environments,” Building and Environment, vol. 78, pp. 183-198, 2014.
[7]
A. Mavrogianni, A. Pathan, E. Oikonomou, P. Biddulph, P. Symonds and M. Davies, “Inhabitant actions and summer overheating risk in London dwellings,” Building Research & Information, vol. 45, no. 1-2, pp. 119-142, 2017.
[8]
A. Pathan, A. Mavrogianni, A. Summerfield, T. Oreszczyn and M. Davies, “Monitoring summer indoor overheating in the London housing stock,” Energy and Buildings, vol. 141, pp. 361-378, 2017.
[9]
A. D. Peacock, D. P. Jenkins and D. Kane, “Investigating the potential of overheating in UK dwellings as a consequence of extant climate change,” Energy Policy, vol. 38, pp. 3277-3288, 2010.
[18] D. Butler and A. Dengel, “Review of co-heating test methodology,” NHBC Foundation, 2013.
[23] CIBSE, “TM52: The limits of thermal comfort: avoiding overheating in European buildings,” Chartered Institute of Building Services Engineers, 2013. [24] B. M. Roberts, D. Allinson and K. J. Lomas, “Overheating in dwellings: a matched pair of test houses with synthetic occupants,” in CIBSE Technical Symposium, 12-13 April 2018, London, UK, 2018.
[10] S. M. Porritt, P. C. Cropper, L. Shao and C. I. Goodier, “Ranking of interventions to reduce dwelling overheating during heatwaves,” Energy and Buildings, vol. 55, pp. 16-27, 2012. [11] R. V. Jones, S. Goodhew and P. de Wilde, “Measured indoor temperatures, thermal comfort and overheating risk: Post-occupancy evaluation of low energy houses in the UK.,” Energy Procedia, vol. 88, pp. 714-720, 2016. [12] A. Beizaee, D. Allinson, K. Lomas, E. Foda and D. Loveday, “Measuring the potential of zonal space heating controls to reduce energy use in UK homes: the case of un-furbished 1930s dwellings,” Energy and Buildings, vol. 92, pp. 29-44, 2015. [13] Department for Communities and Local Government, “English Housing Survey 2014-2015: Headline report,” Crown Copyright, 2016. [14] B. Roberts, D. Allinson, K. J. Lomas and S. Porritt, “The effect of refurbishment and trickle vents on airtightness: the case of a 1930s semi-detached house,” in 38th AIVC Conference, Nottingham, UK, 2017. [15] BRE, “The Government’s Standard Assessment Procedure for Energy Rating of Dwellings,” Building Research Establishment, Garston, Watford, 2014. [16] G. Bauwens, P. Standaert, F. Delcuve and S. Roels, “Reliability of co-heating measurements,” in First Building Simulation and Optimization Conference, Loughborough, UK, 2012. [17] D. Johnston, D. Miles-Shenton, J. Wingfield and M. Farmer, “Whole house heat loss test method (co-heating),” Centre for the Built Environment, Leeds Metropolitan University, 2012.
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Enhancing Thermal Mass Performance of Concrete
The built environment and its patterns – a view from the vision sciences
Prof A J Wilkins DEPARTMENT OF PSYCHOLOGY, UNIVERSITY OF ESSEX arnold@essex.ac.uk
Dr Olivier Penacchio DEPARTMENT OF PSYCHOLOGY, UNIVERSITY OF ST ANDREWS op5@st-andrews.ac.uk
Dr Ute Leonards SCHOOL OF PSYCHOLOGICAL SCIENCE, UNIVERSITY OF BRISTOL Ute.Leonards@bristol.ac.uk
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Abstract
1. Introduction
Visual patterns are all around us. Despite overwhelming
In his seminal book on Survival through Design, architect Richard Neutra stressed the need for objective criteria to judge the quality of design in architecture (Neutra, 1954). In particular, he, Frank Lloyd Wright and others raised concerns that the environments we create might directly impact on our ability to function as human beings, affecting our behaviour, our emotion and our ability to think (Robinson, 2015); i.e. our well-being. Yet, 60 years after the first publication of Neutra’s book, we are still surprisingly far from criteria to define the quality of design in the sense that Neutra understood them.
evidence from the visual sciences that some visual patterns, in particular highly-geometric and repetitive patterns, can be aversive, patterns in our visual environment are rarely considered with regard to their impact on brain, behaviour and well-being. Yet, attempts toward developing healthier, more inclusive cities recently attracted negative headlines, for example for their use of dazzling floor patterns in public spaces that lead to discomfort, avoidance behaviours and falls, particularly in older citizens. Recent developments in analysis now allow us to measure and predict adverse effects of patterns in the real world. Here, we show that aversive patterns are rare in natural scenes but prevalent in modern man-made settings. They occur at every spatial scale, partly because of modular construction, partly because of artistic expression. We review the evidence that visual discomfort and other adverse neurological and behavioural effects arise from aversive patterns, and hypothesise that this is because of the way our visual system has evolved to analyse scenes from nature. We finish our review with an outlook for future research and by proposing some simple ways of preventing adverse effects from visual environments, using urban design as example. Keywords
New developments in translational research in the cognitive neurosciences now start to see neuroscientists and architects working together to investigate the impact architectural design might have on the person as a whole, including their brain (see e.g. Robinson & Pallasmaa, 2015) and mind (see e.g. Maslin, 2012). In this article, we propose that vision sciences might not only be able to help to define one of Neutra’s objective criteria for design, but to tackle the wider issue of modern living, namely how the context of the (visual) world we live in affects our behaviour, our physical and mental abilities.
2. Discomfort can be caused by patterns, and these uncomfortable patterns are common in the man-made urban environment In this paper we focus on a phenomenon known as “visual stress” induced by repetitive, geometric patterns around us. Geometric patterns, particularly patterns of stripes, can be uncomfortable to look at (Wilkins et al., 1984). They can induce illusions of colour, shape and motion, and can bring on a headache, particularly in patients with migraine (Marcus & Soso, 1989) (see Figure 1 for an example of a pattern used in clinical practice to test a person’s susceptibility to visual stress). In patients with photosensitive epilepsy, geometric patterns of
Visual patterns; visual discomfort; migraine; urban environment; design; architecture.
Figure 1. A glaring pattern used to elicit symptoms of visual stress.
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this kind can even evoke epileptic seizures (Wilkins, Darby, & Binnie, 1979). The aversive properties of patterns are important not only because they might induce dramatic neurological consequences in visually-sensitive individuals, but also because there are consequences that are subtle and insidious: aversion to patterns may interfere with reading (Wilkins & Nimmo-Smith, 1987; Wilkins et al., 2007) and with other tasks that require visual search of spatially-repetitive material to find target objects (Singleton & Henderson, 2007); repetitive floor patterns may even interfere with walking trajectories (Leonards, Fennell, Oliva, Drake, & Redmill, 2015).
(c) duty cycle (the proportion of the cycle that the stripes are bright;) (d) contrast (the difference in the luminance of the bright and dark stripes expressed as a proportion of the sum of the luminances).
Note that this article is not concerned with trying to judge artistic expressions in design but concentrates purely on how the outcomes of our visual environment might affect human behaviour.
3. Examples of problems from patterns Many patients with migraine report that their headaches can be visually triggered. Harle and colleagues (Harle, Shepherd, & Evans, 2006) described some of the triggers, which include patterns of stripes such as the doormat shown in Figure 2. Sometimes the patterns can be so unpleasant that they affect healthy individuals who do not suffer migraine. When this is the case, the national press sometimes become involved as happened in the case of the “rug that will make you sick” (Daily Mail 6 February 2012) and the “headache carpet in hospital” and similar instances listed by Wilkins (1995, Chapter 8). Readers who are unfamiliar with patterns of this kind may wish to google “patterns that make you sick”.
Figure 3. Spatial parameters of patterns that evoke perceptual distortion in normal observers (broken lines) and paroxysmal electroencephalographic activity in patients with photosensitive epilepsy (solid lines). Effects of (a) size; (b) spatial frequency; (c) duty cycle; and (d) luminance contrast. From Wilkins (1995).
Figure 2. A doormat with stripes that can trigger epileptic seizures and migraines.
4. Parameters of uncomfortable stripes The characteristics of uncomfortable patterns of stripes that induce perceptual distortions, discomfort and seizures were described by Wilkins et al. (1984) and are summarised in Figure 3. Figure 3 shows the effects of: (a) size (angle in degrees radius subtended at the eye); (b) spatial frequency (the reciprocal of the period of the grating expressed in terms of the angle this spatial period subtends at the eye);
Figure 4. A pattern on railings photographed at various distances to show how the effects of pattern size and spatial frequency combine to determine discomfort.
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Figure 4 shows that the effects of a spatially-periodic pattern (in this case from a railing) depend on the distance from which the pattern is viewed. The viewing distance determines both the spatial frequency of the pattern and the angle the entire pattern subtends at the eye. The distance at which the railing is most unpleasant depends on the interplay of these two factors. The unpleasantness increases with the subtense of the pattern and reaches a maximum at a spatial frequency of about three cycles per degree of visual angle, i.e. when the spatial period of the pattern (a pair of light and dark stripes) subtends about 20 minutes of arc at the eye. As a rough estimate, one’s thumb held at an arm’s length corresponds to two degrees of visual angle (O’Shea, 1991); a black and white striped pattern of three cycles per degree would thus provide six black and six white stripes covering an area as wide as the thumb at arm’s length .
5. Predicting the adverse effects of visual images other than stripes Discomfort can occur not simply from basic geometric patterns but from more complex images. Recent work has shown that a simple mathematical algorithm can predict discomfort from images of all types, including (but not restricted to) stripes (Penacchio and Wilkins, 2015). Our research suggests that it does so sufficiently well to be of direct use in predicting discomfort and would thus provide a simple tool to avoid uncomfortable visual environments, and uncomfortable design more generally. This algorithm is based on a mathematical technique known as Fourier analysis: any image can be construed as made up of spatiallydefined waves having a wide variety of wavelengths, amplitudes, orientations and phases. Waves of the appropriate amplitudes, orientations and phase are added one to another to create the image. These waves thus comprise the Fourier components of an image. The wavelength of each wave is usually specified by its reciprocal, its spatial frequency. When images are analysed in this way, the waves with long wavelength (low spatial frequency) are typically of greater amplitude than those with short wavelength (high spatial frequency), see Figure 5.
Figure 5. Illustration of the component waves in Fourier analysis. The variation in luminance over space (luminance profile) of the sample shown at the top and enlarged in the first row of the left hand inset can be thought as composed of the addition of the waves shown below, and numbered 1-5. The amplitude decreases with their spatial frequency as shown in the right-hand inset.
In images from nature, there is on average a simple relationship between the amplitude of the wave, s, and its spatial frequency, f: the amplitude is roughly proportional to the reciprocal of frequency, i.e. s ~ 1/fa where a is close to 1 (Field, 1987). When the amplitude and spatial frequency for natural images are plotted on log-log axes, the 1/f spectrum has a straight line with a slope close to -1 (see right inset in Figure 5). Images that have a spectrum with a slope that substantially departs from 1/f are uncomfortable to look at, irrespective of what they represent. Periodic patterns of stripes such as Figure 1 depart radically from 1/f so the algorithm identifies them as problematic. Juricevic, Land, Wilkins, and Webster (2010) asked observers to rate the discomfort of images composed of filtered noise or randomlydisposed, randomly-sized, rectangles. For both categories of image, the discomfort was minimal when the Fourier amplitude spectrum had a slope of -1 (expressed on log-log coordinates) and increased when the slope was substantially greater or smaller than -1. Note that this held even for white noise and blurred images, which clearly depart from 1/f and are perceived as rather uncomfortable to look at (Juricevic et al., 2010). However, it is not simply the slope of the amplitude spectrum that is critical in determining visual discomfort. Fernandez and Wilkins (2008) showed images of non-representational modern art to a variety of observers. Again, images with a 1/f spectrum were rated as comfortable to look at. In this experiment, however, the uncomfortable images had a spectrum that departed from 1/f in terms of the shape, not the slope, of the Fourier amplitude spectrum. The uncomfortable images had a curvilinear spectrum with an excess of contrast energy at mid-range spatial frequencies relative to that expected from the 1/f function. Mid-range spatial frequencies are those to which the human visual system is generally most sensitive (Campbell & Robson, 1968). Using artificial images made by filtering random noise, Fernandez and Wilkins (2008) showed that departures from 1/f were responsible for discomfort, but particularly if the departures registered an excess energy at a spatial frequency close to three cycles per degree. By exchanging the phase and amplitude of comfortable and uncomfortable images, they also showed that discomfort was determined by the amplitude rather than the phase information entailed in the image. O’Hare and Hibbard (2011) used images constructed from filtered noise and controlled for the apparent luminance contrast of the stimuli. Again, an excess of energy at midspatial frequencies determined discomfort ratings, although with a spatial frequency tuning that was slightly lower than that obtained by Fernandez and Wilkins (2008). A Fourier amplitude spectrum is two-dimensional because it reflects the periodicity of the images at all orientations (vertical, horizontal and all orientations in between). The studies described above measured the Fourier amplitude spectrum by averaging over all orientations. Such averaging over orientations loses the distinction between periodicity in one orientation and that in another. Wilkins et al. (1984) showed that checkerboards (which have contrast energy in several orientations) are less uncomfortable than stripes in which the energy varies in only one orientation. Penacchio and Wilkins (2015) therefore measured the Fourier amplitude in two dimensions. Instead of averaging over all orientations and fitting a straight line on log-log
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coordinates, as had previously been done, Penacchio and Wilkins (2015) fitted a cone with slope of -1 to the two-dimensional log amplitude spectrum. The residual error in the fit provided a useful index that could predict how uncomfortable the image was. Indeed, the residual error increased as the structure of the image departed from that expected for a natural image. To test the generality of their approach, Penacchio and Wilkins (2015) used five categories of images obtained from seven different image sets: photographs of everyday scenes, of buildings, and of animals, images of randomly-generated polka dots and non-representational art. All images were rated for their visual discomfort. Despite the large range of images, the index explained 17% of the variance in judgements of discomfort. The prediction was improved when residuals were weighted to take account of the greater sensitivity to mid-range spatial frequencies, as reflected in a published estimate of the contrast sensitivity function (Mannos and Sakrison, 1974). From these two principles gleaned entirely from the literature (i.e. extent of residual error in 2D log amplitude spectrum and weighting of residuals based on human spatial frequency sensitivity function), Penacchio and Wilkins (2015) were able to explain an average of 27% of the variance in judgments of discomfort without fitting any specific parameters . In summary, two related factors were found to predict judgments of discomfort: 1 – departure from the statistics of natural images, and 2 – excess of energy at the spatial frequencies to which the human visual system is generally most sensitive. It is worth keeping in mind that ratings of discomfort from one person tend to correlate with those from another person with a coefficient of only about 0.8 across individuals and studies (Penacchio & Wilkins, 2015). Indeed, across the population, sensitivity to patterninduced visual stress seems to lie on a continuum (Wilkins, 1995). This intrinsic variability limits the variance that can be explained by any model, deterministic or otherwise. Moreover, the algorithm by Penacchio and Wilkins (2015) only analyses the luminance of images without considering their chromatic content, which may also have an influence on judgement of discomfort (Haigh et al., 2013). It is therefore remarkable that an algorithm as simple as this was able to explain a comparably large proportion of the variability in discomfort induced by different types of image – the more so, because the images were sourced from the web and were not calibrated or otherwise matched (see Penacchio & Wilkins, 2015 for a discussion on possible confounds due to low image quality).
6. Explaining the adverse effects of patterns – some speculatione In the previous section we showed that a simple algorithm can predict reasonably well how much visual discomfort different types of image might evoke. But why is this the case? It is tempting to speculate that, over the course of human evolution, the visual system has adapted to process efficiently those images of the environment human beings were mostly exposed to (Attneave, 1954; Barlow, 1961); i.e. those from the natural world such as grass
and woodland. Not surprisingly then, there is a large body of evidence in support of the hypothesis that visual processing is most efficient when images have the spatial characteristics of natural images (e.g. Atick & Redlich, 1992; Field, 1987; Graham, Chandler, & Field, 2006). For example, the human contrast sensitivity function is highly efficient for encoding images with the 1/f structure (Atick & Redlich, 1992) inherent in natural images. Several psychophysical studies have shown that performance in discrimination tasks is at its best when the amplitude spectra of the stimuli are close to 1/f, and that performance consistently drops with departures from 1/f (Girshick, Perry, Super, & Gallogly, 2001; Knill, Field, & Kersten, 1990; Parraga, Troscianko, & Tolhurst, 2000). In the same vein, using a binocular rivalry paradigm in which the two eyes are presented with a different image, each image competing with the other, Baker and Graf (2009) showed that images whose amplitude spectrum is close to 1/f dominate over images with other amplitude spectra.
7. Design has got more uncomfortable over the last century We have reviewed evidence that visual images can be uncomfortable to look at when they do not possess the spatial characteristics of natural scenes. Our modern world is built from repetitive elements, and these elements are often used as the basis of design. This applies at all spatial scales, in buildings at one extreme of scale and in written text, web page design, or clothing at the other extreme. Here, we will concentrate on the large scale most relevant to architecture and building design. First, images of the modern urban environment conform less to 1/f than do images of the modern rural environment, as can be seen in the following demonstration. We analysed images of urban and rural scenes using the algorithm by Penacchio and Wilkins (2015). The images were sourced from entries to a photographic competition of images of Britain held by the British Broadcasting Corporation (BBC). The images were published on the BBC website, conveniently categorised by the BBC into those with urban and those with rural content. Consecutive samples of 200 urban and 200 rural images were analysed, and the urban images had larger residuals than the rural ones (p<<0.0001, Cohen’s d=0.63). Given that the residuals predict discomfort from the image, it would appear that rural images may be, in principle at least, more comfortable to look at. Designers have long supposed that images from nature are restful and restorative (Korpela, Ylen, Tyrvainen, & Silvennoinen, 2010), and recent studies have involved the measurement of cerebral haemodynamics in the study of such restoration (Pati et al., 2014). The urban environment appears to have become less and less like that in nature over the last 100 years, partly as a result of changes in architectural design. To exemplify these changes, we sourced images of apartment buildings on Google that were categorised by year of construction, and analysed the images by the algorithm of Penacchio and Wilkins (2015). The increase in the residuals with each decade from 1890 to 2000 is shown in Figure 6.
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Figure 6. Log of the residual error after a cone with slope of 1/f has been fitted to the two-dimensional Fourier amplitude spectrum of images from a Google image search for photographs of apartment buildings, classified by year of construction. An average of 22 images per decade were analysed. Bars show standard error. The regression explains 30% of the variance of the means for each decade. Without the outlier from the 1930s, the regression explains 37% of the variance.
Given that images with large residuals are generally less comfortable than those that have small residuals and conform to 1/f, it would then appear that the urban environment in which the majority of today’s society lives has become visually less comfortable over the last century. This is partly because stripes are such a common feature of recent architectural and industrial design. Although high-contrast stripes are sometimes used in an attempt to produce a safer environment (e.g. high-contrast edging on stairs to increase the conspicuity of steps; markers to reduce speed on the road, and so on), they are also used simply as decoration or appear as a by-product of modular construction. In their publication, Penacchio and Wilkins (2015) included a set of case histories in which artistic, industrial and architectural design has led to problems. These ranged from modern art that gave headaches, to epileptic seizures induced by swirling stripes in street design. In each case, the measure of residuals predicted the complaints: the designs all had percentile scores higher than the 90th percentile of the set of images (~~800) investigated in total. The problematic designs consisted of spatially-repetitive elements, usually but not exclusively of stripes. Figure 7 shows examples. Note that the examples have been adapted slightly so that the locations of the buildings cannot be identified.
Figure 7. Examples of repetitive patterns that have caused complaints.
As we stressed above, there are a great many striped patterns in the modern urban environment. This was dramatically illustrated by the case of a patient with pattern-sensitive epilepsy who suffered absence seizures only when she looked at striped lines (Wilkins, Andermann, & Ives, 1978). Telemetric recording over the course of several days showed frequent absences (about 22/hour). These were reduced to two per hour when the patient wore spectacles with one frosted lens which, in laboratory studies, demonstrably reduced her susceptibility to stripes. Evidently, it was the many and varied stripes in her environment that were responsible for her seizures. Note that we do not want to imply that stripes should be avoided at all costs. Using stripes to accentuate areas of danger might be highly beneficial. The point we want to bring across is that it might be time we started to investigate more carefully the extent and the circumstances under which repetitive visual patterns are used in our environment, their luminance contrast and spatial frequency content, and the impact these might have not only on people suffering from migraine or photosensitive epilepsy, but more generally on people’s behaviour, health and well-being. We now consider what can be done in the short term to reduce possible adverse effects of patterns in everyday visual environments, how to estimate the strength of adverse effects, and for whom this might be important. Again, we will concentrate on building design, but similar criteria would concern any kind of visual environment a person is exposed to.
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Figure 8. Examples of patterns that prevent people seeing the structure of the surface they are walking on. (a) Led to headlines in the Daily Mail on May 12th 2014: “Woman, 74, suffers horrific injuries after she was dazzled by “invisible” new kurb stones”. (b) The pattern on the carpet masks the edges of the stair treads. (c) and (d) The stair treads form a perceptually unstable pattern owing to their high contrast.
8. Making our visual environment more comfortable In the previous section, we saw how repetitive elements in today’s built environment lead to departures from the characteristics of natural images, making them more uncomfortable to look at. In this section, we consider briefly some of the more obvious ways in which the modern environment can be made more comfortable. It is common practice in domestic buildings to place pictures on internal walls and to train plants to grow so as to cover external walls. The use of plants has been taken to extremes in the vertical forest skyscrapers of Milan, the Los Conquistadores Street Office in Santiago and the greenery curtains of Anjo City in Japan. The plants that cover the buildings not only provide insulation but a textured surface that breaks up the regularity of the structure, turning it into a scene closer to that found in nature. In street design, it is popular to use paved surfaces in public spaces. The tessellation of the stones can provide uncomfortable patterns, particularly when oblique rays from the sun highlight the grouting, thus increasing contrast of the tiles themselves. The same is true on a smaller scale in interior design, particularly with respect to tiled floors and tiled or panelled walls. Not only can the patterns be uncomfortable to look at, but even for people not prone to visual discomfort, the orientations within such patterns can make them veer away from their intended walking direction, thus directly impacting on their gait (Leonards et al., 2015). Moreover, dazzling floor and background patterns can make it difficult to perceive curbs on pavements and edges of steps, or to find objects.
Although patterns may be fun for the designer and those in the population who are less sensitive to aversive patterns, one has to consider the entire community that is exposed to the design, in particular in public spaces; this community includes a large number of people with neurological and mental difficulties. Among these, the most common are those who suffer migraine (at least 15% of the general population worldwide as estimated by the WHO in their latest headache fact sheet in April 2016), but increased pattern sensitivity has been described for stroke patients (Beasley & Davies, 2013), patients with multiple sclerosis, chronic fatigue syndrome (Wilson, Paterson, & Hutchinson, 2015), children with Tourette syndrome and with autism spectrum disorder (Ludlow & Wilkins, 2016), and people with dyslexia. There is even evidence that visual pattern sensitivity might vary with personality style (Hollis, Allen, Fleischmann, & Aulak, 2007). Figure 8 provides examples of aversive design. The first caused an elderly person to fall and severely injure herself, the others gave headaches. The negative impact of such patterns on the visual system can be reduced by using thin grouting that contrasts little with the surround (thereby reducing the energy in the pattern), or by breaking the pattern up through mixing of different-sized tiles or bricks. Even when the bricks are identical, it is possible to tessellate a surface without repetition provided the bricks have the appropriate shape (Figure 9). Wall and floor coverings often incorporate a repetitive design, and sometimes the pattern is evident only if large surfaces are covered. Such patterns, when striped, have been associated with complaints (Bonato, Bubka, Ishak, & Graveline, 2011; Penacchio & Wilkins, 2015; Wilkins, 1995, Chapter 8) and are best avoided.
9. Advice for design What could be simple rules of thumb for designers and others to estimate (and reduce) the visual stress of their environment, based upon the precepts outlined in the previous sections?
Figure 9. Examples of repetitive patterns that have caused complaints.
Avoid larger areas of repetitive stripes that are simply a feature of design, particularly when each stripe subtends at the eye an angle of between four and 60 minutes of arc because these are the most aversive (Wilkins, 1995), see Figure 3. You can calculate the angular
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subtense (A) from the width of a stripe (w) and the distance from which it is likely to be viewed (d), as follows: A = arctan(w/d). Stripes can consist of groups of elements when they form a repetitive pattern, as in Figure 4. Keep in mind that the spatial frequency of the patterns depends strongly on the viewing distance; stripes that closeup are widely spaced and thus do not induce discomfort can do so when looked at from further away; Where patterns of repetitive elements are necessary for construction, keep the visible area as small as possible. Avoid repetitive elements that are as wide as the space between them, because evenly-spaced stripes are the most aversive. If stripes are unavoidable, choose the reflectance to keep the difference in luminance less than 10% of the average luminance, and the difference in colour (separation in UCS chromaticity) to a minimum. This minimises the aversive effects (Haigh, Cooper, & Wilkins, 2015). Note that this advice may run counter to current building regulations, particularly those concerning stair treads;
distributions within the visual environment and eliminating as much as possible those that clearly diverge from the distributions of natural scenes, would be a comparably easy mechanism to improve architectural design and avoid costly failures leading to accidents or rejection of the building by users, finally moving towards Neutra’s goal: to find objective criteria for good design of our (visual) environment; and to do this quite generally – not just in architecture. Author contribution AJW provided a first draft of the manuscript and it was subsequently elaborated by all authors. Acknowledgements Our interest in aversive patterns was kindled long ago by Dr Fred Andermann (Montreal Neurological Institute) and his patient.
Remember that if the repetitive elements are of different heights, they can cast a shadow, and the shadow can increase the contrast between them; Common sources of repetitive patterns are carpets and doormats, see Figure 1. It is possible to choose mats with lower contrast. Paving provides another source of repetitive patterns, and these patterns can be broken up (and their visual interest increased) by tessellating paving stones of a variety of sizes. Tiling in washrooms is another source of repetitive pattern. The grouting can be chosen to reduce the contrast; When it is possible to use computer-aided design to provide views of the completed project, subject these images to the algorithm described by Penacchio and Wilkins (2015).
10. Conclusion The above review has highlighted the translational and interdisciplinary power of current research in the visual sciences related to patterninduced visual stress. In particular, we argue that a solid scientific evidence base has begun to emerge to suggest that visual design in modern environments can cause visual discomfort and accompanying adverse effects, most probably related to neurological processing within the brain, possibly processing that is inefficient. The extent of negative consequences on everyday functioning arising from such pattern-induced visual stress remains as yet unknown, but is likely to go far beyond the classic cases of visual discomfort, migraine and epilepsy that are mostly described in the literature. Future research might want to concentrate on possible links to vision-related risk of falls, place-specific cognitive abilities, emotional consequences and social inclusivity of places inducing visual stress, to name but a few. Other areas might include neuro-aesthetics and mental health. With regard to urban design we propose here that one criterion of good (and inclusive) design should be the avoidance of visual patterns that cause visual stress. A simple and fast mathematical algorithm can flag design areas that are most likely to lead to such symptoms based on their visual characteristics: Estimating the spatial frequency
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Leonards, U., Fennell, J. G., Oliva, G., Drake, A., & Redmill, D. W. (2015). Treacherous Pavements: Paving Slab Patterns Modify Intended Walking Directions. PLoS One, 10(6), e0130034. doi: 10.1371/journal.pone.0130034 Ludlow, A. K., & Wilkins, A. J. (2016). Atypical Sensory behaviours in children with Tourette’s Syndrome and in children with Autism Spectrum Disorders. Res Dev Disabil, 56, 108-116. doi: 10.1016/j.ridd.2016.05.019
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Abstract The catastrophic fire at Grenfell Tower on 14 June 2017 killed 72 people and shocked the world. It also changed many more lives forever. As well as the police and public inquiries, which are ongoing, it led to an independent review of Building Regulations and Fire Safety, led by Dame Judith Hackitt, a Chartered Engineer and Fellow of the Royal Academy of Engineering. Her review, and the associated activity around building regulations in England, is the most significant review in over a generation, since the 1984 Building Act, and is widely recognised as being a once in two generations opportunity to reform building regulations in England. It will also have implications in Wales, Scotland and Northern Ireland, which are watching closely. Moreover, it will extend beyond building regulations, which apply up until a building is complete and handed over, into the operation of the building and subsequent maintenance and minor works. This review activity is being watched closely outside the UK too, with three states in the Australian Commonwealth introducing legislation related to cladding on tall buildings in October 2018. Keywords Grenfell, Fire Safety, Building Regulations
This paper summarises the activity associated with the review, and also considers where we are likely to see changes in practice as a result of Grenfell Tower. Many have said that the industry must change in order that we reduce, as far as is humanly possible, the prospect of any such fire occurring again. Dame Judith was asked to focus on “High Rise Residential Buildings” (HRRBs), with a twofold purpose: • To make recommendations that will ensure we have a sufficiently robust regulatory system for the future; • To provide further assurance to residents that the complete system is working to ensure the buildings they live in are safe and will remain so. Dame Judith was asked to: • Map the current regulatory system (i.e. the regulations, guidance and processes) as it applies to new and existing buildings through planning, design, construction, maintenance, refurbishment and change management; • Consider the competencies, duties and balance of responsibilities of key individuals within the system in ensuring that fire safety standards are adhered to; • Assess the theoretical coherence of the current regulatory system and how it operates in practice; • Compare this with other international regulatory systems for buildings and regulatory systems in other sectors with similar safety risks; • Make recommendations that ensure the regulatory system is fit for purpose with a particular focus on multi-occupancy high-rise residential buildings. The review began by calling for evidence from interested parties. As well as contributing to responses by the Construction Industry Council and Royal Academy of Engineering, CIBSE responded with a detailed contribution on façade engineering aspects of the review developed by a working group of the Society of Façade Engineers1. Dame Judith’s interim report was published on 18 December 20172, in which she concluded that the current system of regulation of HRRBs is not fit for purpose. Dame Judith commented on some of her observations during the initial phase of the review, saying: “I have been shocked by some of the practices I have heard about and I am convinced of the need for a new intelligent system of regulation and enforcement for high-rise and complex buildings that will encourage everyone to do the right thing, and will hold to account those who try to cut corners. “Changes to the regulatory regime will help, but on their own will not be sufficient unless we can change the culture away from one of doing the minimum required for compliance, to one of taking ownership and responsibility for delivering a safe system throughout the life-cycle of a building.” She gave extended evidence later that day to the Communities and Local Government Select Committee of parliament3. This underlined her concerns and set out a number of reasons for them:
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1) Current regulations and guidance are too complex and unclear. This can lead to confusion and misinterpretation in their application to high-rise and complex buildings; 2) Clarity of roles and responsibilities is poor. Even where there are requirements for key activities to take place across design, construction and maintenance, it is not always clear who has responsibility for making it happen; 3) Despite many who demonstrate good practice, the means of assessing and ensuring the competency of key people throughout the system is inadequate. There is often no differentiation in competency requirements for those working on high-rise and complex buildings; 4) Compliance, enforcement and sanctions processes are too weak. What is being designed is not what is being built and there is a lack of robust change control. The lack of meaningful sanctions does not drive the right behaviours; 5) The route for residents to escalate concerns is unclear and inadequate; 6) The system of product testing, marketing and quality assurance is not clear. In late January there was an industry summit, which was accompanied by a statement which reinforced the interim findings and set out the next steps: • The current system for ensuring fire safety in high-rise and complex buildings is not fit for purpose; • A culture change is required, with industry taking greater responsibility for what is built – this change needs to start now; • This applies throughout the building life-cycle, both during construction and occupation; • A clear, quick and effective route for residents to raise concerns, and be listened to, must be created. The Report set out six broad areas for change: • Ensuring that regulation and guidance is risk-based, proportionate and unambiguous; • Clarifying roles and responsibilities for ensuring that buildings are safe; • Improving levels of competence within the industry; • Improving the process, compliance and enforcement of regulations; • Creating a clear, quick and effective route for residents’ voices to be heard and listened to; • Improving testing, marketing and quality assurance of products used in construction. The second and final phase of the Review set out to develop practical solutions that will deliver these areas of change and support the direction of travel set out in the Interim Report. Nothing short of a major overhaul of the whole system was envisaged, and Dame Judith undertook to work with all those who shared her ambition and drive
to create a new and robust regulatory framework and system that supports this. Across all sectors of the industry she called for radical thinking about the immediate actions that could be taken to lead to sustainable change. Industry leaders at the summit committed to work to create a new system that will work effectively and coherently, with working groups formed to develop innovative solutions in the following key areas: Design, construction and refurbishment: Establishing what industry and regulators need to do to fully embed building safety during the design and construction phase; Occupation and maintenance: Identifying what building owners, landlords and regulators need to do differently to ensure that building safety is prioritised when a building is occupied and throughout its life-cycle; Products: Determining how the product testing and marketing regime can be improved; Competency: Establishing how competency requirements for key individuals involved in building and managing complex and high-risk buildings should change; Residents’ voice: Determining the best way for residents to be given a clear, quick and effective statutory route for raising concerns on fire safety; Regulation and guidance: Resolving whether central Government ownership of technical guidance is the most appropriate model for complex and high-risk buildings. An expert group was also formed by the Ministry of Housing, Communities and Local Government (MHCLG) to inform the government response to the recommendation to consider how the suite of Approved Documents could be structured and ordered to provide a more streamlined, holistic view, while keeping the right level of relevant technical detail. The author chaired this working group. Its recommendations were submitted in March to Dame Judith and accepted in full in her final report. In response to Grenfell, MHCLG also established a very comprehensive web-based compendium of Grenfell-related information4. Dame Judith’s final report was published by government on 18 May 20185. In response to her remit, to “make recommendations that ensure that the regulatory system is fit for purpose with a particular focus on multi-occupancy high-rise residential buildings”, the report focuses on “higher risk residential buildings”, defined as residential buildings over 10 storeys. However, Dame Judith notes that a number of her recommendations should extend to multi-occupancy buildings. This has prompted considerable debate, and current thinking within the Construction Industry Council (CIC), which brings together all the professional bodies in the industry in England, is that her recommendations should apply to all multiple-occupancy residential buildings, regardless of height. The report envisages a new regulatory system, bringing the Fire Service, Health and Safety Executive and Building Control services together in a “Joint Competent Authority” (JCA), which is proposed to oversee both construction and operation of higher-risk buildings,
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and to take responsibility for the enforcement of the Building Regulations and other relevant legislation relating to HRRBs (see Chapter 1). It calls for a series of Gateways for new HRRBs and major projects on existing HRRBs, which would entail significant scrutiny and sign-off by the JCA. It also envisages a role for the JCA in overseeing a safety case system for existing HRRBs through the whole operating life of the building (see Chapters 2 & 3). The report calls for radical change in the current Building Regulations and associated guidance (Chapter 6), and for provision of full digital models for all new higher-risk buildings, and for them to be maintained through the life of the building (Chapter 8). However, it is Chapter 5 that sets out the (potentially) most farreaching recommendations for CIBSE and its members, and indeed for all professionals, relating to competence. Recommendation 5.2 of the Review calls for the professions to come together to provide a new and more robust and effective system for recognising and maintaining competence. The terms used in the Report could not set a clearer challenge to the built environment professions, and merits reading in full. Dame Judith, a past-President of the Institution of Chemical Engineers, was clear that professional bodies in the built environment and property and fire safety sectors must find a way to work together. She calls on government to supervise the process and, if we cannot deliver, to step in. The message is really clear, and the response was almost immediate, with a working group being formed. Other key recommendations from the report that will impact building services engineers include: • A clear model of risk ownership, with clear responsibilities for the client, designer, contractor and owner to demonstrate the delivery and maintenance of safe buildings. The project team will be held to account by the new JCA. This new body will have powers during both construction and operation of a building, and for existing buildings; • A set of rigorous and demanding duty-holder roles and responsibilities to ensure a stronger focus on safety during a building’s design, construction and refurbishment. These roles will be broadly aligned with the Construction (Design and Management) Regulations. Penalties for those “who choose to game the system and place residents at risk”, as Dame Judith describes them, will also be more serious. • Moving towards a system where ownership of technical guidance rests with the industry, with oversight by government. A clearer package of regulations and “truly outcomes-based” guidance which will be simpler to navigate while reflecting the level of complexity of building work. It acknowledges that “prescriptive regulation and guidance are not helpful in designing and building complex buildings, especially in an environment where building technology and practices continue to evolve, and will prevent those undertaking the work from taking responsibility for their actions”; • A more effective product-testing regime with clearer labelling and traceability because “the current process for testing and ‘certifying’ products for use in construction is disjointed, confusing,
unhelpful, and lacks any sort of transparency”. Poor procurement practices to be tackled to ensure high-safety, low-risk options are prioritised and full life-cycle cost is considered when a building is procured; • A digital record from initial design intent through to construction, including any changes that occur during occupation, is also called for, effectively producing a model similar to one created under BIM Level 2. This digital model will create “a golden thread of information” about each HRRB which is handed over to the owner. The information can then be used to demonstrate to the regulator the safety of the building throughout its life cycle; • Clearer rights for residents are also proposed, as well as responsibilities where resident activity can create risks that may affect others. Much of the report is eminently sensible and says a lot of things that have needed saying for some time, although there is still a lot of detail to be resolved. It is not yet clear how the government will proceed to address the full package of recommendations, but the Secretary of State for Housing, Communities and Local Government has already set out what will happen next: • Government has consulted on restricting the use of desktop studies as a means of assessing the fire performance of external cladding in lieu of an actual fire test. The consultation sought views on whether desktop studies should be used at all, and whether or not they are appropriate for construction products, wall systems, or for any other purpose; • Government has consulted on clarifications to Approved Document B (Fire) over the summer and on banning the use of combustible materials in cladding systems on high-rise buildings. Legislation on this point is thought to be imminent at the time of writing. A full technical review of Part B of the Regulations, and of the Guidance, is also very likely. The full Government response was promised for “late autumn 2018” and so may have emerged by the time you are reading this paper. In the meantime, Grenfell is not the only high-rise fire to have occurred. In Melbourne, Australia, the Lacrosse Building suffered a significant fire to which aluminium composite panels contributed. There were no casualties, and the sprinkler system helped to control the spread of the fire. There was also a multi-storey hotel fire in Ballymun, Dublin recently. Thankfully, again there were no serious casualties but the building suffered significant damage. Following a full investigation, the State of Victoria has now introduced legislation to limit the use of such material on buildings in the State. New South Wales has also introduced new regulations. Queensland, which has an unknown number of buildings with potentially-combustible cladding, has introduced legislation requiring owners of high-rise buildings to register them with the State Building Control Commission by next March, and those that appear to be at risk of having combustible cladding will then be investigated further. It is not just England that has the problem with this cladding.
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Grenfell was an awful event, and has devastated many lives. There does appear to be a resolve to change the way that we build and manage high-rise residential buildings in the UK, but we are now getting to the challenge of starting to deliver change, and not talking about it. In the meantime, it is clear that the problems we have in England are not unique, and those elsewhere are also taking a close look at the way they regulate their buildings in the light of their own experience, and also that at Grenfell.
References 1. https://www.cibse.org/News-and-Policy/Consultations/Closed-Consultations/ Independent-Review-of-Building-Regulations-and-Fir 2. https://www.gov.uk/government/publications/independent-review-of-buildingregulations-and-fire-safety-interim-report 3. The evidence session along with subsequent correspondence with the committee is at: https://www.parliament.uk/business/committees/committeesa-z/commons-select/communities-and-local-government-committee/ 4. https://www.gov.uk/guidance/building-safety-programme 5. https://www.gov.uk/government/publications/independent-review-of-buildingregulations-and-fire-safety-final-report
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