Lighting Journal October 2016

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JOURNAL The publication for all lighting professionals

WALK THIS WAY What pedestrians actually look at when they’re walking the streets at night LIGHT FANTASTIC The health benefits of circadian lighting CLEAR AS DAYLIGHT How to overcome the challenges of representing daylight

October 2016

Mixity, by Valmont. When we hear this word used in reference to lighting columns we think of the obvious... Columns that are constructed from a mix of materials such as Aluminium, Wood, Galvanised Steel, and Stainless Steel. This form of “Mixity” is becoming more and more popular in todays world. The next step will be to go beyond mixing materials with in a single product, but to use a mixture of different products across the whole of the project. A good example is a hospital installation, here we encounter multiple areas with varying uses such as entrance roads, refuse areas (for waste / rubbish / recycling), car parks (staff / visitor), social spaces for patients, main entrance, drop off points, children’s play areas and the like. Historically, if a plan to revive the area’s lighting to update or upgrade the lighting solutions a mid range solution would be opted for, as an example an anodized aluminium column, and rolled out across the site utilizing the allocated budget of £500,000. Now, with Mixity, there is an alternative approach. While RETAINING the same budget but being sensitive to the context of installations giving an “added value solution” only to the areas that will actually benefit and in turn a lower calibre of product for the “low-value” areas. For example: By taking this approach we maximise the use of “cost effective” and “high end” solutions with a sensitive consideration to the areas... Installing an anodized aluminium column in refuse areas, a waste? Using a stepped tubular galvanised column in refuse areas, logical? Valmont offers you the opportunity to channel all of these products via a single source supplier bringing this added value approach within reach....

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Our understanding of how lighting affects our circadian rhythms is growing all the time, yet lighting designers still have a long way to go to properly understand, let alone implement, circadian (or biologically-active) lighting. This has to change, argues Inessa Demidova










The advantages of LED are well-documented. But there is still not enough debate about its potential environmental effects in terms of circadian disruption, glare, uniformity and colour temperature, writes Brian Healy




Lighting within the healthcare sector has to be efficient, reliable and fit for its task purpose. It also needs to replicate natural light as much as possible, as it is becoming increasing recognised this can aid patients in their recovery. Paul Davidson looks at how to square these complex circles


All lighting designers appreciate the importance of maximising the benefits of daylight within an interior space. But describing and representing daylight within a space remains challenging. Dr Jemima Unwin and Longyu Guan explore some of the latest, and changing, thinking around daylight metrics


By gaining a deeper insight into what pedestrians actually look at when they’re walking pavements at night, Peter Raynham and Navaz Davoodian are helping lighting professionals to understand better what it is they’re doing right, and doing wrong, when it comes to illuminating urban areas



Six months from now all employers with a pay bill of more than £3 million will start paying into the government’s new apprenticeship ‘levy’. With ministers providing an update to their plans in August, what do we now know? Nic Paton reports


The EU’s ban on inefficient directional halogen lamps came into effect last month, meaning directional (reflector) mains voltage halogen lamps such as GU10, R63 and R50 are no longer allowed to be placed on the market. But this will create its own challenges around LED dimming, warns Sam Woodward

Former Institution President Joe Woodhouse sadly passed away in July. Bob Stevenson looks back at his life, while Richard Ryan adds his recollections about how Joe inspired him to enter the profession

The uncertain economic climate since June’s ‘Brexit’ vote could mean a rise in payment and contract disputes. The Construction Act, which is 20 years’ old this year, is one of the key pieces of the law lighting professionals can use to protect themselves. Howard Crossman and Kirstie Sowter look at how it has changed over the years

The latest publication from LUCI highlights 15 innovative light art installations and how they helped their respective municipalities to regenerate and transform their urban areas. Emma Cogswell is impressed


Central Management Systems (CMS) nowadays offer the lighting engineer ever more control over his or her lighting stock. But CMS is not a new idea, and the concept of central control has bubbled through the literature since the earliest days of public street lighting. Simon Cornwell delved back into the archives








A stretch of the A143 through the small Suffolk village of Great Barton is hosting a pilot connected lighting scheme that, it is being argued, has the potential to transform the economics of smart city applications. Lighting Journal took a look


Emergency lighting will be firmly in the spotlight at next month’s LuxLive. Lighting Journal took a look at what lighting professionals can expect

Pedestrians enjoying the night life in Liverpool city centre – research is helping lighting professionals better understand what pedestrians look at when out at night

Lighting Journal October 2016

Not all LED street lights are made equal

Editorial Volume 81 No 9 October 2016 President Kevin Grigg, Eng Tech, AMILP Chief Executive Richard G Frost BA(Cantab) DPA HonFIAM Editor Nic Paton Email: Editorial Board Tom Baynham MEng MA (Cantab) Emma Cogswell IALD Mark Cooper IEng MILP Graham Festenstein CEng MILP MSLL IALD John Gorse BA (Hons) MSLL Alan Jaques IEng MILP Nigel Parry IEng FILP Richard Webster Designed by Julie Bland Advertising Manager Andy Etherton Email: Published by Matrix Print Consultants Ltd on behalf of Institution of Lighting Professionals Regent House, Regent Place, Rugby CV21 2PN Telephone: 01788 576492 E-mail: Website: Produced by

Matrix Print Consultants Ltd Unit C, Northfield Point, Cunliffe Drive, Kettering, Northants NN16 9QJ Tel: 01536 527297 Email: Website:

The more we understand, the less we know. It’s a bit of an over-simplification but, in many respects, this is the thread running through this edition. As Inessa Demidova of Arup has highlighted, scientific advances are gradually giving us a much clearer understanding of how the recently discovered intrinsically photoreceptive retinal ganglion cells in our eyes influence our circadian, hormonal and behavioural systems. Yet how we translate this knowledge into effective circadian (or biologically-active) lighting is still a real challenge for lighting professionals. Similarly, our understanding of the benefits, and value, of daylight as a stimulus and a contributor to wellbeing is advancing all the time.Yet how we describe and represent daylight in the context of lighting design, and how we develop daylight metrics that actually then correlate with the needs of building users, is something the industry continues to wrestle with, as Dr Jemima Unwin and Longyu Guan of UCL have also explored. Or take our article by Jemima and Longyu’s colleagues at UCL, Peter Raynham and Navaz Davoodian, outlining the fascinating research they are currently conducting on pedestrian vision at night. All of us, of course, will have tramped the urban landscape at night (in my case undoubtedly a little worse for wear on occasion). But what we are we actually looking at; what are ‘our patterns of fixation’, how (and why) do they differ from daytime, and what role does artificial light play in these differences? Those, as Peter and Navaz make clear, are much harder questions to fathom. Finally, I’ve distilled down for you the latest guidance from the government on how the new apprenticeship ‘levy’ is set to work from next April. Certainly, our understanding is now clearer. There is considerably more flesh on the bones of the government’s plan, and it’s possible to get an outline sense at least of how the levy will work in practice for big and small employers alike. But our knowledge of what these changes will actually mean in terms of attracting and bringing skilled young people into our industry remains somewhat opaque. The fact new employer-designed training and assessment standards for construction have yet to be approved by government is a concern, as is the continuing lack of clarity around how the various complicated new funding formulas are going to work. Lighting as an industry desperately needs to be attracting young people. That’s only going to happen if, first, they are offered the right skills, incentives and career pathways. Second, educating them will need to stack up financially for training providers. Third, employers will need to feel the cost of the levy is offering them a worthwhile return on investment. The worry is, six months out, we’re a long way off knowing the answer to any of this. Nic Paton Editor

© ILP 2016 The views or statements expressed in these pages do not necessarily accord with those of The Institution of Lighting Professionals or the Lighting Journal’s editor. Photocopying of Lighting Journal items for private use is permitted, but not for commercial purposes or economic gain. Reprints of material published in these pages is available for a fee, on application to the editor.

Lighting Journal October 2016

4 Lighting and health

LIGHT FANTASTIC Our understanding of how lighting affects our circadian rhythms is growing, yet lighting designers still have a long way to go to properly understand, let alone implement, circadian lighting. This has to change, argues Inessa Demidova


he recent discovery of intrinsically photoreceptive retinal ganglion cells within the human eye has led to a massive push in the amount of research being undertaken by academics, scientists and lighting professionals to understand the exact role our visual system plays in regulating our body rhythms [1, 2, 3]. Within this, circadian (or biologically-active) lighting is a relatively new area of research. So new, in fact, that when researching this article, I could not even find a universally agreed-upon definition of what circadian lighting is. I therefore propose to define circadian lighting as ‘an artificial lighting system which is designed to influence human circadian rhythms by changing the qualities of light throughout the day’. In this article, I’m not going to explain the potential benefits of using circadian lighting. A plethora of publications by lighting manufacturers [4, 5, 6], recent publications in mainstream media [7, 8] as well as research institutions have all covered the benefits of this, although there is undoubtedly still more scope for debate and research. What, instead, I intend to do is focus on the gap between concepts and practical implementations when it comes to circadian lighting. Having read extensively on the topic, having worked on projects that use circadian lighting principles, having spoken to lighting designers, manufacturers and researchers, for me, there is one other key question that needs to be explored, namely: ‘What can be improved with the current way we, as lighting designers, work on schemes that include a circadian lighting element?’ As professional lighting specialists, we have to make sure, if we propose lighting with additional benefits, that it has the required effect. But it also, of course, has to be feasible and within the realm of contemporary construction industry capabilities. Circadian lighting presents additional challenges and considerations. Just as LEDs brought new issues which didn’t

exist with halogen and incandescent lighting, so circadian lighting has a potential to further complicate design and installation. What this article therefore intends to address is a few issues that, as a lighting designer, I have come across and which I believe require our additional attention. OVERALL CONCEPT ISSUES 1. Circadian lighting metrics do not correspond to metrics that are commonly used by lighting designers and those available from lighting equipment manufacturers. As outlined in Report on the First International Workshop on Circadian and Neurophysiological Photometry published by CIE [9], non-visual responses to light require the adaptation of traditionally used units because of using different photoreceptors in the human eye and having different spectral sensitivity compared to our image-forming systems. It was highlighted that illuminance (unit: lux) and correlated colour temperature (CCT) (unit: kelvin) values have proved insufficient when the effects achieved under supervision of the scientists needed replication. Furthermore, it is suggested lighting used in previous laboratory and application studies might not have been sufficiently adapted to the non-visual reception system which, in turn, might have led to considerably higher lighting levels and higher energy consumption than necessary. This is still very much an area for discussion within the world of circadian rhythms research, and we can only expect more refined systems and ways to measure the effects of light on our bodies. 2. The teams who are responsible for creating office environments rarely ever include consultants on human biology or even environmental psychologists. This may lead to a lack of understanding on how systems such as circadian lighting should be implemented. It is currently unclear who should be responsible for setting

Winter sun over Edinburgh: how our eyes respond to light is much more complex than reacting to a particular wavelength or brightness

Lighting Journal October 2016

Lighting and health 5 up the exact algorithm that will decide how the lighting should be changing throughout the day. Lighting design consultants, naturally, have a wealth of knowledge in the field of light and lighting, but this area touches on realms of human biology that do not necessary overlap with our field of expertise. For example, it is particularly unclear how circadian lighting models should cater for individual differences in circadian phases – in one space the wake/sleep cycle can vary significantly depending on an employee’s age, lifestyle, commute pattern to and from work and so on.

Cool lighting against metal panelling can make skin appear unhealthy

3. Human response to light is much more complex than reacting to a particular wavelength or particular brightness by a single type of cells in our eyes. There is a growing understanding that more parts of our visual system take part in adjusting the circadian rhythms and a number of light characteristics are affecting our circadian rhythms and performance, such as the light amount and spectrum, the timing, modulation and duration of exposure as well as accumulated qualities of light received prior to that by an individual. It is worth noting that this applies to light incident to an individual’s eye as opposed to lighting reaching a task surface. 4. An overall concept of creating comfortable workplaces, following the circadian models offered by researchers, may not work so well with other aspects of wellbeing in space. For example, rooms with aluminium panelling and very cool, nearly blue 1,7000K light have shown the highest level of raising self-reported alertness [10, 11]. However, architects and interior designers in a team would generally not welcome this type of lighting and surfaces, as it would negatively affect rendition of skin tones and overall atmosphere of a space. For example, one interior designer I interviewed noted that some lighting modes in tuneable white systems ‘can look visually weird and then impact negatively on aesthetics and so wellbeing’. 5. The effects of light on circadian biology are cumulative

and are there throughout the day and the night. This means it is important to take into account the lighting conditions in an environment, and surrounding an individual, throughout the dayand night. And it may be, of course, that these are outside the scope of control, for example within their homes or during their commute. EQUIPMENT ISSUES 1. Lighting designers in their practice rely on a wide range of lighting tools. Despite a growing number of companies taking up on the subject and offering solutions with tuneable correlated colour temperature (CCT) light sources, finding a particular type of luminaire has proven to be an issue. Three main complications are as follows: • Lack of good optical performance wall washer, in other words a downlight with asymmetrical light distribution that would direct light to vertical surfaces. • Close-offset linear grazing equipment. Due to the nature of individual LEDs being close to a surface which needs to be lit, proper mixing of colours has proven to be a difficult task to achieve. • Narrow-beam downlight with soft round edges. 2. There can be significant differences between different manufacturers. At the moment there doesn’t seem to be an agreement or a standard on how circadian lighting should be implemented. This causes a number of potential compatibility issues between different manufacturers of luminaires and lighting control systems. For example, the range within which the luminaires would change its colour does not necessary correlate across the market, proprietary and specific to a manufacturer control protocols are used. 3. Commissioning is becoming ever-more complicated. Observation over a longer period of time is necessary to establish the quality of transitions and more sophisticated methods of measuring the circadian element may be required once a methodology is established. The quality of control system and its adjustability is more prominent as, given the number of changes throughout the day, the ability for it to be gradual is of extreme importance. One of the designers I have interviewed gave me an example of a project where the entire tuneable white lighting system had to be decommissioned because people who used the space found the changes too abrupt and frequent. 4. Additional data is required for light sources. According to current published research, ipRGCs (intrinsically photosensitive retinal ganglion cells which are located in our eyes and are responsible for regulating our circadian rhythms) are the most sensitive to 480nm light, so logically there should be information available on spectral power distribution for the considered light sources. However, in reality we struggle to get information on much simpler parameters, such as Colour Rendering Index (CRI) for a particular standard colour. So one can foresee potential complications and delays collecting all the necessary information. As our understanding of the non-visual effects of light develop, we may need to have an additional set of light measurements to give us a fuller picture. SUGGESTED LIGHTING PRINCIPLES 1. To establish the baseline for lighting design with a circadian element, at least a basic assessment of daylight availability is needed more than ever. This should be the starting point for every scheme with a circadian lighting component.

Lighting Journal October 2016

6 Lighting and health

Light amount, spectrum, timing, modulation and duration of exposure all play a part in adjusting our circadian rhythms

2. Early strategy should include an outline control strategy, ideally developed within a team including a specialist on human biology. In this strategy, a minimum level of performance should be specified to ensure gradual changes throughout the day will be as non-disruptive as possible. In addition to that, this exercise can be used to define the principles of changes throughout the day, the amount of individual control of the brightness and colour of luminaires, changes throughout the season and, roughly defined, a schedule for periods of activation and deactivation. For example, in open-plan office areas circadian lighting would most likely be centrally controlled, but a degree of individual control can be offered with task lighting. 3. Circadian lighting-specific parameters for the luminaries should be defined at earlier stages. A scope for circadian lighting can be outlined at this stage taking into account daylight availability and intended occupancy. One example can include focus pods, which can have independent lighting scenarios which can trigger a more alert phase. Another example would be to rationalise lighting equipment and only use circadian lighting for areas of continuous occupation and where daylight doesn’t provide enough stimulation to visual system. 4. Traditional lighting design principles should not be left out when designing for non-visual responses. Attention still should be given to appropriate lighting to vertical surfaces. Lighting designers should be paying even more attention now to working with ceiling and vertical surfaces, as these areas are most important for non-biological responses. The research shows that areas of the upper part of the retina are more effective in suppressing melatonin in humans [12]. The CIE report [9] provides a general recommendation to maximise the lighting area, while keeping luminance levels low in order to avoid glare effects. Indirect lighting is suggested for this but this is not prescriptive and is open to interpretation. 5. The transition from daytime active phase to evening, aimed at gradual relaxation and preparation for a better

Lighting Journal October 2016

night’s sleep, should take into account not just change in colour temperature but overall brightness of the environment. Unlike during the daytime hours, big bright-lit surfaces would not be advisable for stimulating the right body reaction.Typical recommendations of general lighting being supplemented by task lighting (for example desk lights or free-standing lamps) in warm colour temperature and, preferably, spectral distribution suited for deactivation phase fits well for that purpose. This approach is already widely advised in contemporary lighting design and has been a topic for discussion within our office as well as in email correspondence with other lighting designers. 6. If there is a need for an individual to work through until a later phase it is suggested that ambient lighting is dimmed down and task lighting is used as the primary source of illumination. Warm colours with only little biological effects can maintain good vision without strongly influencing circadian effects in the evening, while cooler colours with enriched blue content used over the day are providing good vision and higher biological effectiveness simultaneously. The evening and night scenario also allows to reduce the laminar light distribution and a change to spot-like illumination exclusively. This also allows substantial reductions in the amount of energy needed for lighting, as only the visual tasks and emotional aspects have to be respected in these hours. Reductions in energy consumption may be further achieved by including sensors and intelligent controls, without deductions in illumination quality. 7. Trials and post-occupancy visits should play a major role in the development of such applications. This can be fed back to the research community working in this area and provide incentives for change and improvement. This is of particular importance as at the moment there is a pronounced lack of independent studies based on actually implemented circadian lighting designs observed over long periods of time.

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8 Lighting and health GENERAL PROPOSALS AND PRINCIPLES FOR CIRCADIAN LIGHTING SYSTEMS 1. Circadian lighting has to form part of a wider approach of providing higher quality built environments. For the human visual system, availability of daylight and a view out has been proven to increase user satisfaction and reported wellbeing [13]. 2. Artificial lighting with quality is paramount. We need to be very careful when choosing the luminaires and how the spaces are lit if we want to have a chance of achieving the desired effect. In particular, light sources with enough spectral power within around 480nm should be specified in order to achieve elevated alertness levels and improved cognitive performance. This, however, should not compromise the quality of white light delivered and attention should be given to colour rendering and avoidance of flicker. 3. Ever closer collaboration between manufacturers of luminaires, control systems and lighting consultants is going to be required. This approach opens up further possibilities to develop innovative solutions, but the lighting manufacturers should be open to collaboration and modification according to the needs of lighting designers. Further involvement of the research organisations working within circadian lighting can help to direct the lighting customisation process. 4. A more active engagement in the research and development of circadian lighting concepts is required. During my interviews it became apparent that conferences such as ‘BioWi’ in Germany, which focus on the latest developments in biologically-active and circadian lighting attract surprisingly low numbers of lighting designers. This suggests that the connection between the researchers and practitioners can be improved in both directions. The lighting design industry has accumulated a wealth of knowledge on specifics of human perception in design and architecture research fields, not just psychology and biology, but is often overlooked outside of the narrow field in which we specialise. On the other hand, working together with researchers we can gain first-hand knowledge as well as develop a common language between research and applications. 5. Industry standards need to be developed, tried and tested. Currently there are a number of documents in circulation, which offer an insight on a number of very important topics, such as circadian lighting metrics and circadian lighting applications. These include German DIN SPEC 67600 design guidelines on biologically effective illumination, European BS EN 16791 Quantifying irradiance for eye-mediated non-image forming effects of light on humans (draft version only) and recent publications by the CIE, amongst others. CONCLUSION The effects of artificial light exposure on health and wellbeing are being increasingly recognised as an important factor within built environment design. It is therefore paramount that people who are making the decisions about lighting solutions are as well-informed as possible. Although there is still vast scope for scientific research and a lot of questions to be answered in this field, the first results of circadian lighting applications open up a promising field for improvement in quality of the indoor environment, when also combined with advances in other areas, such as healthier materials for indoor finishes and better air quality. This provides us with both a challenge and an opportunity to

Lighting Journal October 2016

expand on the role of lighting design within architecture. There is no reason why we should not try to implement these schemes if, indeed, they can positively affect the wellbeing of people working in these environments. However, it is worth emphasising that further real-condition testing is needed, and using circadian lighting principles should in no way overwrite or overshadow good lighting design principles. Finally, this trend will continue to have an impact on the client’s expectations about what a good lighting scheme can provide. With a growing body of knowledge and technological advances within the lighting industry, we should not miss the opportunity to create innovative and beautiful environments as well as having a more positive effect on people’s lives. Inessa Demidova is a lighting designer at Arup Lighting


[1] Brainard, G. C., et al. (2001). ‘Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor.’ J Neurosci 21(16): 6405-12. [2] Thapan, K., et al. (2001). ‘An action spectrum for melatonin suppression: evidence for a novel non-rod, noncone photoreceptor system in humans.’ J Physiol 535 (Pt 1): 261-7. [3] Berson, D. M., et al. (2002). ‘Phototransduction by retinal ganglion cells that set the circadian clock.’ Science 295(5557):1070-3. [4] Schlangen, L. (2013) ‘The effect of light on our sleep/ wake cycle’ Philips. [Online]. Available: Education/Lighting_Academy/how-to-beat/Daily-sleepwake-cycles-whitepaper-FINAL.pdf. [Accessed: 04- Sep2015]. [5] Osram, (2014) ‘Light in its third dimension. The biological aspect of lighting design for better quality of life.’, Osram. [Online]. hires/333819/light-in-its-third-dimension.the-biologicalaspect-of-lighting-design-for-better.pdf [Accessed: 04- Sep2015]. [6], (2015) ‘TUNABLE WHITE’, Zumtobel. [Online]. Available: en/index.html. [Accessed: 04- Sep- 2015]. [7] Bramley, E. (2014) ‘Urban light pollution: why we’re all living with permanent “mini jetlag”’, the Guardian. [Online]. Available: [Accessed: 04- Sep- 2015]. [8] BBC News, (2015) ‘Are night shifts killing me? – BBC News’. [Online]. Available: magazine-33638905. [Accessed: 04- Sep- 2015]. [9] CIE TN 003:2015 Report on the First International Workshop on Circadian and Neurophysiological Photometry, 2013, CIE – INTERNATIONAL COMMISSION ON ILLUMINATION, 2015. [Online]. Available: http://www.cie. [Accessed: 04- Sep- 2015]. [10] Viola, A. U., L. M. James, et al. (2008). ‘Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality.’ Scand J Work Environ Health 34(4): 297-306. [11] DIN. (2013). Biologically Effective Illumination – Design Guidelines, DIN SPEC 67600 (2013-04). Deutsches Berlin, Germany: Institut für Normung e.V. [12] Glickman, G., et al. (2003). ‘Inferior retinal light exposure is more effective than superior retinal exposure in suppressing melatonin in humans.’ J Biol Rhythms 18(1):719. [13] P. Tregenza and M. Wilson, (2011) Daylighting. London: Routledge, pp. 8-10, 128.


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10 Lighting and health

OUT OF THE BLUE The advantages of LED are welldocumented. But there is still not enough debate, and questioning, about its potential environmental effects in terms of circadian disruption, glare, uniformity and colour temperature, writes Brian Healy


he LED revolution in outdoor lighting is well and truly under way and there is no doubt it can, should and is playing a big part in reducing energy demands globally. It brings with it many benefits, but it has to be said, its deployment is not without its critics, but we will come back to that.... I have been involved in public lighting since setting out in 1970 as a raw electrical apprentice taken on by Ken Shaw, who went on later to become president of the ILE, as it was then. Ken rang a tight but happy ship at Beeston and Stapleford Urban District Council (B&SUDC) and I was guided and mentored through my electrical apprenticeship by three great time-served electricians with strong street-lighting bias. Very interestingly and with much success, I would later team up with another Ken Shaw-protégé in my career with Philips – take a bow, Bob Cox. I simply never dreamed back in those early days of my apprenticeship that my career and involvement in lighting would end up taking me to Japan, the USA, the Middle East and most of Europe on numerous occasions in the pursuit of better and improved lighting. A few months into the job in 1970 as a young apprentice I assisted in converting the first trunk route in England to SON (the A453). B&SUDC was a well-funded authority adopting the latest technology to lower operating costs. In 1974 B&SUDC became Broxtowe BC and here I would finish my training and become a fully-fledged electrician. At BSUDC we were one of the first authorities with a new-fangled Simon articulated MEWP, and I experienced many differing scenarios from street-lighting to commercial and residential maintenance and sewage station upkeep. Every day was different, with many an eye-opening experience: memorable roman candle cable faults, twocore bell-wire ring mains, exploding MH lamps and my first emergency attendance at a fatal RTA as a first responder; flooded sewage sumps, swing pin lamp-holders, new ideas from Merlin Gerin, Siemens – all game changers. Eventually, after running my own department in a neighbouring authority, sales came calling for me and what

Lighting Journal October 2016

a privilege working initially in power distribution, then into lighting with Iwasaki, Philips and GE, all enabling me to be heavily involved in the market introduction of some wonderful innovative new lighting technologies into the industry, both in exterior and interior application. Color Arc, FEC, T8, T5, Son Comfort, CDO, Cosmopolis, LED – all spearheading market penetration of technical innovation that drove major change, these shape our professional development and stay with us. And it here that my argument in the context of lighting and health really begins, and gets interesting. In my experience, change and innovation generally always sees resistance when introducing new ideas. But it is very clear to me that LED deployment in exterior lighting has a higher-thanaverage number of detractors; maybe as an industry we are failing to take notice of some of the issues surrounding LED deployment and, with it, the frustrations felt by some stakeholders. Is there a case to answer that, in the race to save money and energy, we are guilty of deploying LED technology too rapidly, without encapsulating the benefit of evolving technology development as we saw over time with previous light sources in application? It’s also appropriate to consider how the technology itself differs from all previous generations of artificial light and, as such, maybe we need to better attempt to understand its potential impacts. LIGHT AND FIRE For centuries, mankind relied on light in a natural way from the sun or reflected moonlight and, of course, man’s first artificial light initially came from fire. Our modern world of electrically-driven artificial sources has a relatively short history of just over a century, and our knowledge of light in all its forms and vision is growing fast. There is a vast amount of information and research papers on light and its circadian and other health and environmental impacts now readily available online. So let’s take a look at those sources deployed in exterior application and how they compare: It’s immediately clear that the output of an LED is very

Figure 1. Sunlight and relative spectral shift over day

Lighting and health 11

Figure 2. Typical moonlight

Figure 3. Spectral outputs for Tungsten and discharge

Figure 4. Typical LED spectral distribution output

significantly different to any artificial light source previously deployed. The % spectral output of LED in the blue end of the spectrum is significantly higher than the corresponding output of SOX and SON and latterly prevailing HID white light that make up the bulk of the public lighting asset.

The key driver for LED adoption is clearly energy savings, as local authorities scramble to manage and optimise budgets. The savings aspect of LED deployment is widely accepted as necessary, but what of the concerns for human circadian disruption and the impact of white light at night on surrounding fauna? Everywhere I go I see some very compelling business cases being put forward to support a dash to LED. What I don’t see is evidence of the same degree of effort in due diligence in looking at impact studies. Evidence exists in research to suggest we should at the very least exercise some degree of caution. Stakeholders, far and wide, globally are asking serious questions of our industry and of LED technology in terms of suitability in minimising circadian disruption, glare, uniformity issues, suitability of (correlated colour temperature) CCT in deployment and how it impacts on the surrounding environment. So what are the considerations in delivering an energy saving lighting scheme and why is it receiving so much criticism by some? To my eyes, all the following need to be considered: • Efficacy, glare/comfort, ambiance and uniformity • Security, safety, and control • Environmental So where are the issues?The main critics of LED point to glare, unsuitable CCT deployment and poor design and uniformity. With previous generation technology it was widely understood that, when we used pot optics, the very essence of good luminaire design was to ‘hide’ the light source up in the optic and minimise glare. Now, strangely, it’s suddenly the norm to take a high-intensity light source, stick it behind a clear optic and shine it directly at someone entering the space. Mmmm! Clearly, some in the supply chain have back-tracked on good luminaire design principles and, without a cover glass, also choose to ignore how dirt is attracted to these optics. One can only speculate as to what has driven this negative design shift. Thankfully, some quality suppliers are using non-direct reflector optic systems or comfort optic systems. Some also argue the use of LED without minimising its blue light output has also potentially serious consequences for the insect population. I read glib marketing statements almost every day about LED being ‘insect or bug friendly’ because of no UV output. The reality is the vast majority of insects have a very high response to blue light and, as such, may be additionally drawn to and entrapped by an LED light source rich in blue light. ROAD LIGHTING DISCOMFORT Figures 5 and 6 above are the response curve for the eye of a cabbage root beetle compared to that of an onion fly. We can

Lighting Journal October 2016

12 Lighting and health

Figure 5. The response curve for the eye of a cabbage root beetle

Figure 8. The amount of fluorescence is directly related to the wavelength of light entering the eye

Figure 6. The response curve for the eye of an onion fly

see the cabbage fly has a much lower response to UV than the onion fly; crucially both have a very significant response to blue light. The dotted line represents the lower limit of human vision. Some impact studies in Germany suggest serious damage to insect populations as a result. In addition to recognising glare as a result of using very directional sources we also need to recognise we are lighting for an ageing population and the impact of glare can be the cause of serious discomfort. I experienced this myself earlier this year when I travelled a section of UK motorway just relit with LED. My first impression in good weather conditions was wonderful. However, a subsequent trip on a cold wet dark March night revealed to me the most serious and dangerous case of discomfort glare I have ever witnessed. Research (Figure 7 below) shows the amount of perceived discomfort glare from a light source, especially at night, is strongly dependant on the colour composition of the light. In

Figure 7. Perceived discomfort glare from a light source

Lighting Journal October 2016

the graph above, the black lines show the level of reported discomfort experienced by observers viewing light sources of the same intensity, but at different wavelengths. The line with the solid dots is the data from younger research subjects. The lens of the eye actually fluoresces – glows – when exposed to light, as shown on Figure 8. This graph shows how the amount of fluorescence is directly related to the wavelength of light entering the eye. This effect becomes more pronounced as the eye ages and can affect visual acuity in both high and low light levels. It likely adds to the perception of glare at night, making those bluetinted headlights and street lamps more disruptive for older drivers than younger ones. In the US, Federal funding mechanisms are linked to a 3,000K upper limit for LED road lighting. I would advocate we seriously consider replicating that when considering funding or design of new schemes here at home. Additionally, many optional dimming and control options are available that can play their part too in furthering energy reduction to offset the small premium in moving to a warmer CCT. Apple’s famous recent software update, which brought in a ‘night shift’ mode to reduce blue light, and the fact that one of the UK’s leading sleep therapists recently advocated that GPs actively monitor patients’ exposure levels to blue light are further indicators of rising concerns in the blue light debate. Our light source choice and its delivery can’t be absolute on energy; light quality and comfort has to play its part too. I would urge all of my industry colleagues with input in design to truly understand that LED is different and needs to be treated as such. We should be challenging our chosen supply chain and the status quo, and insist on solutions that address blue light by driving down CCT, tackle glare from directional sources and uniformity issues. It’s not just about insects either, our dash to LED lighting has an impact on every aspect of the natural world around us, including us ageing humans. In fact, a 2016 study is suggesting LED lighting is already impacting on bat foraging habits. If we don’t act now to stem the tide and adjust to a more measured and appropriate deployment, we risk leaving a long legacy of wasted opportunity to get it right. Brian Healy is director of Bright Design Carbon Solutions

Lighting and health 13


Lighting within the healthcare sector has to be efficient, reliable and fit for its task purpose. It also needs to replicate natural light as much as possible, as it is becoming increasing recognised this can aid patients in their recovery. Paul Davidson looks at how to square these complex circles


atural daylight has the ability to invigorate and promote a sense of wellbeing within people, so the aim of the lighting designer when working in the healthcare sector should be to replicate these benefits as closely as possible using artificial light sources. Quality of light is achieved through the specification of the optimum light source packaged within the optimum luminaire. For healthcare, lighting should provide a combination of three elements: visual performance in order to maximise work benefits; visual comfort to provide a feeling of satisfaction and stimulation; and an energy-efficient solution with reduced operational and maintenance costs. However, each particular application within the healthcare environment requires specific task-oriented solutions; from basic lighting within storerooms and lighting to facilitate access in corridors and waiting areas, through to ambient lighting for wards and consultancy rooms and very task-specific lighting within operating theatres. LED lighting opens up a whole new range of solutions for the healthcare industry, with the use of luminaires that

Lighting within the healthcare environment requires specific task-oriented solutions, from basic lighting within storerooms, to ambient lighting on wards, and to task-specific lighting within operating theatres

Lighting Journal October 2016

14 Lighting and health

LED can offer a whole new range of solutions for the healthcare industry, including increased lumen performance and more controlled illumination

offer increased lumen performance, a controlled level of illumination with low glare, and others that confer high colour rendering values. LED now has the capability of developing products that assist in providing measures of infection control. CONTINUOUS OPERATION Another important consideration is that hospitals are buildings in use 24-hours-a-day, 365 days a year. This continuous level of operation creates its own issues for a lighting manufacturer to provide a level of illumination that can be maintained over the life of the fitting whilst still retaining the quality of light produced. Installing fittings that provide an extended life to L70 together with a long period of warranty is critical, as this benefit maximises the time period between installation and replacement, whilst also reducing maintenance costs. Glare is important consideration. Choosing fittings with a large surface area or with glare control can provide qualitative illumination without appearing to be too bright or uncomfortable on the human eye. Qualitative lighting within the healthcare environment is important from another perspective, too, our ‘body clock’ or the circadian rhythm. It is well-known that the natural spectral distribution of light constantly changes throughout the day in the angle of inclination, in direction,

Lighting Journal October 2016

in colour temperature and in its distribution, all of which affects the way in which people feel.

Circadian lighting is designed to replicate natural daylight. This is achieved by changing the colour spectrum across a single day. During daylight hours enriched blue light is produced to boost alertness and maintain the day/night cycle. To create the feeling of night, warmer colours with lower levels of illumination provide the most relaxed environment

Attempting to replicate natural light through artificial means can provide much benefit in a hospital environment to aid recovery of patients. Circadian lighting is designed to replicate natural daylight. This is achieved by changing the colour spectrum across a single day. During daylight hours enriched blue light is produced to boost alertness and maintain the day/night cycle. To create the feeling of night, warmer colours with lower levels of illumination provide the most relaxed environment. Circadian lighting is also beneficial in such places as care homes where the elderly tend to be fairly inactive and spend long periods of time sitting within a poorly-lit environment. Maintaining the day/night cycle had the benefit of providing daytime alertness to undertake tasks. The night period enables individuals to benefit from qualitative sleep, which can also mean less disruption from residents during the night, when staffing levels tend to be lower. Installing lighting equipment that can provide this type of colour temperature changing solution provides benefits and is achieved by having dual colour LEDs within the luminaire at 6,500K and 2,700K. Mixing both the colour and output achieves this artificial colour spectrum. Paul Davidson is technical and project manager for The Aurora Group

Lighting and health 15

Luton & Dunstable University Hospital: a £6 million LED refurbishment has created a better ambience


As part of a £6 million refurbishment throughout the existing hospital complex, Luton & Dunstable University Hospital (LDUH) wanted a more cost-effective, energy-efficient LED lighting installation, as well as one that created a more welcoming ambience throughout. Existing fittings, which were primarily tungsten halogen and fluorescent in type, were to be upgraded with LED technology. As Leslie Barras, mechanical and electrical capital projects manager at LDUH (pictured below), explains, creating a safe, clean and friendly environment has been a core objective. ‘It is extremely important that patients feel as at ease and as comfortable as they can, especially in the consultancy rooms.’ A four-step strategy was applied: continual dialogue with the client, a full lighting review of the existing system’s effectiveness, a proposed LED solution with calculated energy savings, and a plan to minimise occupancy downtime Products comprised approximately 1,500 fittings from the Aurora VersiTile and dSeries ranges. Within the corridors, the hospital chose to install new T-bar ceilings to create a better feel within the facility. To these we added our VersiTile energyefficient LED panels with an edge-lit design for both superior light performance and longevity. A high transmission diffuser drastically reduces uncomfortable glare. We also manufactured a bespoke luminaire, combining panel and emergency in one surface-mounted solution, where a flush-mount unit was not possible. Within the patient rooms, we proposed innovative colour-

changing LED lighting, with tuneable colour of between 3,000K and 6,500K to increase visual comfort. Within the consultancy rooms, dimmable IP44 downlights were specified in order to provide the quality of light to enable patients to feel at ease yet sufficient task lighting for the medical staff to do their jobs. These downlights feature a reduced heatsink, which allowed their installation in the shallow ceiling voids. Dimmable units were also installed on to the LED panels. Outside the buildings, corrosion-resistant floodlights were installed. These external fittings were bespoke manufactured to IP65 for long life and to also achieve maximum energy savings at a very efficient >70Lm/W. And the result? All the client’s objectives were met. Our scheme proposal led to 46% energy savings, improved patient experience and enhanced definition for CCTV monitoring. Outdoor lighting replacements will save approximately £15,000 during an eight-year period. In essence, a qualitative hospital lighting solution has been provided, while reducing energy and maintenance costs.

Lighting Journal October 2016

16 Lighting design

CLEAR AS DAYLIGHT All lighting designers appreciate the importance of maximising the benefits of daylight within an interior space. But describing and representing daylight within a space remains challenging. Dr Jemima Unwin and Longyu Guan explore some of the latest, and changing, thinking around daylight metrics


he benefits of daylight have been advocated for centuries, as we see in an ancient limestone relief that shows the Egyptian Queen Nefertiti holding up her daughters to the rays of the sun [1] (Figure 1, below). More recently, the writer and playwright George Bernard Shaw

Figure 1 (above). Nefertiti limestone relief (getty images) Figure 1a (below). Shaw’s revolving shed (image courtesy of:

Lighting Journal October 2016

(Figure 1a) used a revolving shed to optimise his daylit working conditions [1]. As electrical lighting increasingly replaced daylight in buildings, the effect of light on wellbeing was largely forgotten until the discovery of the intrinsically photoreceptive retinal ganglion cells (ipRGCs) which influence circadian, hormonal and behavioural systems [2]. The role of light as a stimulus for these systems is unquestioned, however whether ipRGC activation should be maximised or minimised in buildings is unknown [3]. Despite this, the advantages of daylight are unquestioned as it provides high retinal illuminance and information about the external environment. This is why daylight propagation in spaces where people spend most of their time is an important area of exploration. ‘Daylight factor’ is the ratio of interior to exterior illuminance over a horizontal plane, and has been the dominant metric for daylight design for over 50 years. Whilst the metric has remained the same, working environments have evolved. Figure 2, for example, compares a typical office in the 1970s with one of the present day. From the image of the 1970s, it is clear the desk top (in other words the horizontal working plane) is the most important task area. However, in working environments today, people find that the horizontal desk plane is no longer the only important task area. The most task-intensive planes are, arguably, computer screens on which good visual performance is easy to achieve (by ‘zooming in’ for example). As the use of computers means that people can work from anywhere, the main reason to attend a workplace is to communicate with colleagues, which involves looking at their faces. Therefore, it could also be argued that facial communication is also an important task. To summarise, the emphasis of lighting design has moved away from the lighting of horizontal working planes. Whilst task illuminance is still in use, there is now more emphasis on the appearance of the room and the people in them.

Lighting design 17

Figure 2. Offices from the 1970s (right) and the present day (left)

Therefore, it is worth questioning whether the traditional daylight factor approach meets the needs of modern daylight design and whether there is any scope for metrics which consider daylight propagation in the whole volume occupied by people. A STEP TOWARDS VOLUMETRIC LIGHTING Electrical lighting standards have moved a step forward from the lighting of the horizontal plane. In 2002, the European electrical lighting standard EN 12464-1 removed the term ‘working plane’, and instead recommended illuminance levels on ‘task areas’ (which may or maybe not be on a horizontal plane) and on ‘major room surfaces’ (wall/ceiling/floor) [8]. In the 2011 revision, the standard introduced ‘cylindrical illuminance’. Cylindrical illuminance measures the illuminance on the curved surface of a small cylinder centred at the reference point. To ensure good visual communication and adequate illumination in the volume of space, EN 12464-1 recommends a minimum mean cylindrical illuminance of 50 lux evaluated 1.2m above the floor for sitting people, and 1.6m for standing people [9]. Another metric that can be useful to describe lighting in the volume of occupied space is ‘cubic illuminance’. In this concept, developed by Cuttle [10], the calculation point is a tiny cube on which illuminance is measured on all six faces. From these values the illuminance vector of the calculation point can be deduced. Figure 3 (below right) shows illuminance vectors of multiple calculation points in a daylit room. Drawing the illuminance vectors reveals the indoor ‘daylight flow’ and the spatial distribution of illumination. This can be a useful tool for advanced daylight designs, such as daylighting for a sculpture gallery. However, due to its complexity, cubic illuminance is hardly used in general practice. Even though it is useful for the derivation of other metrics, such as cylindrical illuminance and

hemispherical illuminance, cubic illuminance contains too much information which makes it uneconomical to calculate. Then the question becomes: ‘Is there a simpler volumetric lighting metric?’, ‘Can we make it more approachable for daylighting?’. The answer may lie within the concepts of ‘exitance’ and ‘indirect illuminance’. EXITANCE AND INDIRECT ILLUMINANCE Exitance is the luminous flux reflected by a surface per unit area (as shown in Figure 4 below). Therefore, it equals the illuminance of the surface (E) multiplied by the surface reflectance (R).

Figure 4. Incident flux and exitance

For example, if one wall inside a room was lit to 100 lux and the wall has a reflectance value of 0.8, then there will be 80 lux of exitance reflected back to the space. If exitance is calculated for all major room surfaces, an average exitance value can be obtained to summarise the diffused light in the room. This average exitance value is called Mean Room Surface Exitance (MRSE). This term ‘MRSE’ might be new (proposed by Cuttle [11]), however its underlying concepts are not. Essentially, it is a way of describing

Figure 3. Cubic illuminance (left) and illuminance vectors in a daylit room (right)

Lighting Journal October 2016

18 Lighting design the indoor inter-reflection of light. The same concept is used to calculate the internal reflected component of daylight factor (for example, Hopkinson’s split flux method [12]). MRSE as a daylight metric has some user-friendly traits. Firstly, it is a single number and is easy to calculate to a first approximation using Sumpner’s principle (in any closed system the flux emitted must equal the flux absorbed [13]). The components needed to calculate MRSE are only the total flux entering the window (Φ), the room surface area (A_r) and surface reflectance (R). Secondly, it correlates very well with the electrical lighting standards. The lighting standard EN 12464-1 recommends illuminances on major room surfaces, and this, coupled with guidance on surface finish reflectance, already effectively forces a minimum MRSE. In addition, MRSE may be related to the biological effects of light. Given that ipRGCs are in the retina, a good candidate for driving the response is likely to be illuminance in the plane of the pupil. Moreover, as aversion of gaze is the natural reaction to a direct view of a light source, it is quite likely that the best metric to describe any possible response is indirect pupil plane illuminance. This suggests that MRSE might be a good way of describing the potential of a daylighting design to impact on people’s endocrine systems. While MRSE might look promising in theory, it faces problems in practice [14]. The biggest flaw of the exitance approach is that it does not work so well when a building is open-planned and geometrically complex. Exitance is the flux intensity being bounced back to the space from room surfaces, and MRSE measures the average exitance in the enclosure. However, what if the room is not a closed system? What if there is no ceiling, or one or more internal walls is missing? Open spaces and voids are very common in modern architecture. In a workplace such as that shown in Figure 5 (below right), it is only possible to calculate the exitance from the highlighted surfaces. However, what about the light being reflected from the far back corner of the building, and what about the flux ‘loss’ to the ground floor due to the huge void on the first floor? MRSE works perfectly for a simple ‘box-like’ room geometry, but it cannot be sub-sampled or calculated for open spaces or complicated spaces. A solution to this limitation of MRSE is to use indirect illuminance. The total illuminance of any location facing any direction consists of direct and indirect illuminance (Figure 6). The indirect illuminance is the illuminance produced by one or multiple reflections from internal surfaces. It is a very similar concept to exitance, as both describe the flux intensity through reflections. In fact, the essence of MRSE can be considered to be the average indirect illuminance value of the entire room.

Figure 5. MRSE (left) and open space office [15] (right)

Lighting Journal October 2016

Figure 6. Example of direct and indirect illuminance (on a cube), assuming the window is on the distant left wall

Unlike exitance, which emphasises room surfaces, indirect illuminance can be calculated for any given point of the space (thanks to modern computation). Therefore, it is possible to calculate the indirect illuminance at multiple locations facing different directions, just like calculating cubic illuminance. However, unlike cubic illuminance, where the total illuminance of some directions might be significantly greater than others due to facing the light source, the indirect illuminance values on the other hand are very close on different faces. This means the indirect illuminance values of all faces can be averaged to give the ‘Average Indirect Illuminance of the calculation point’. If multiple calculation points are assigned in the space, the average indirect illuminance at each point can be measured (Figure 7 below right) and from this, a value of ‘Average Indirect Illuminance of the space’ can be calculated. As MRSE, the Average Indirect Illuminance (AIE) of the space describes the overall inter-reflection within the room space. The more calculation points taken to calculate AIE, the closer the result will be to MRSE. However, AIE could be seen as an improvement because it overcomes the weakness of MRSE because it can be sub-sampled and can be calculated regardless of geometry complexities. CONCLUSIONS AND SUGGESTIONS FOR FUTURE RESEARCH Describing daylight in space is challenging. However, as daylight is likely to influence wellbeing, it is an important area of study that requires further research. Whilst this article has shown that there is good theoretical justification for the use of volumetric daylight metrics, this does not constitute grounds for widespread adoption until there is more evidence to show

Lighting design 19 REFERENCES

Figure 7. Indirect illuminance (left) and calculating average indirect illuminance of the space (above)

that such metrics correlate better with the needs of building users compared to traditional metrics. Testing the metric is the hardest part of developing new metrics. An initial pilot study which used data of people’s perceptions of daylight, revealed that Average Indirect Illuminance better reflects people’s perception of daylight adequacy. In a study of three spaces it gave a higher value for a space that had a large window with a passive shading device, compared to daylight factor, and this was well correlated with office workers’ self-reported preferences. The metric will also encourage high-reflectance indoor surface materials. However, daylight metrics can only be reliably tested in a large number of real buildings. The link with people’s perception of daylight is challenging, as impressions are affected by other factors (such as view, weather and so on). Further research will conduct more real-life case studies and compare the performance of different daylight metrics. The incorporation of climate-based daylight modelling into the method will also be explored. In conclusion, as a volumetric lighting metric for daylighting, Average Indirect Illuminance combines the advantages of both MRSE and cubic illuminance. It is one simple number which summarises the diffused daylight within the volume of space, yet it also can be sub-sampled and calculated anywhere in the space. Unlike daylight factor, which only focuses on the working plane, Average Indirect Illuminance better represents daylight in the whole space. If this is found to also relate to how people perceive daylight, then its use may lead to spaces that have a positive influence on wellbeing.

[1] R. Hobday, The Healing Sun: Sunlight and Health in the 21st Century, Forres, Scotland: Findhorn Press, 2000. [2] D. Berson, F. Dunn and M. Takao, ‘Phototransduction by retinal ganglion cells that set the circadian clock,’ Science, vol. 8, 2002. [3] R. Lucas, S. Peirson, D. Berson, T. Brown, H. Cooper, C. Czeisler, M. Figueiro, P. Gamlin, S. Lockley, J. O’Hagan, L. Price, I. Provencio, D. Skene and G. Brainard, ‘Measuring and using light in the melanopsin age,’ Trends in Neurosciences, vol. 37(1), pp. 1-9, January 2014. [4] CCIV 244, ‘Nefertiti as Divine Protector of Akhenaten’s Sarcophagus,’ [Online]. Available: project-5/1120-2/. [Accessed 06 July 2016]. [5] The Telegraph, ‘Shed love: a selection of images of readers’ sheds and sheds of the famous,’ [Online]. Available: http://www.telegraph. html?image=23. [Accessed 06 July 2016]. [6] University of North Carolina, ‘Interior view of office of RAVU in the 1970s,’ [Online]. Available: national_climatic_data_center/Interior/Office%2050s.jpg. [Accessed 06 July 2017]. [7] Hotel-r, ‘Office-19,’ [Online]. Available: hotel/lv/office-19.png. [Accessed 06 July 2016]. [8] British Standard, ‘Light and Lighting-Lighting of work places-part 1: Indoor work places,’ BS EN 12464-1, 2002. [9] British Standard, ‘Light and Lighting-Lighting of work places-part 1: Indoor work places,’ BS EN 12464-1, 2011. [10] C. Cuttle, ‘Cubic illuminance,’ Lighting Research and Technology , vol. 29, no. 1, pp. 1-14, 1997. [11] C. Cuttle, ‘Towards the third stage of the lighting profession,’ Lighting Research and Technology, vol. 00, pp. 1-21, 2009. [12] R. G. Hopkinson, P. Petherbridge and J. Longmore, Daylighting, London: Heinemann, 1966. [13] W. E. Sumpner, ‘The diffusion of light,’ Proc. Phys. Soc (London), vol. 12, pp. 10-29, 1892. [14] P Raynham, ‘Room lighting in the absence of a defined visual task and the impact of mean room surface exitance’, Lighting Research and Technology, April 2016; vol. 48, 2: pp. 190-204., first published on November 27, 2014 [15] Applied Acoustic Design (AAD), ‘£14.5M NATIONAL TRUST’S HEELIS CENTRE,’ 2016. [Online]. Available: [Accessed 06 July 2016].

With thanks to Roderic Bunn, building performance analyst at the BSRIA, for kindly providing data for the pilot study. Longyu Guan is a PhD research student and Dr Jemima Unwin is lecturer in light and lighting at the UCL Institute for Environmental Design and Engineering, The Bartlett, University College London

Lighting Journal October 2016

20 Pedestrians and urban lighting


By gaining a deeper insight into what pedestrians actually look at when they’re walking pavements at night, Peter Raynham and Navaz Davoodian are helping lighting professionals to understand better what it is they’re doing right, and doing wrong, when it comes to illuminating urban areas


t present, the specification for road lighting can be justified on the basis that it must meet a number of assumed needs of pedestrians. These needs are best 1 summarised by Van Bommel and Caminada . They proposed that it was necessary for pedestrians to detect obstacles on the footpath, be able to know where they are and to know where they are going, to be able recognise other people’s faces and to be able to do this in a comfortable and pleasant environment. The exact nature of the pedestrian tasks has always been a subject for conjecture and their implications for lighting requirements even more so. For example, in the original work by Van Bommel and Caminada they decided that face recognition was needed at a distance of 4m and then with a Class

limited range of subjects they found that 0.8 semi-cylindrical lux was needed to achieve this. Then someone working on standards (in the 1990s) worked out that with typical road lanterns if you go 5 lux on the horizontal you would also get 0.8 lux cylindrical. Thus, the evolution of the current set of standards has depended on many layers of assumptions, and thus the whole basis of road lighting for pedestrians may well be wrong. CURRENT STANDARDS The basis for road lighting practice in the UK derives from the EN 13201 series of European standards. It is normal practice to base lighting for pedestrians on one of the P Classes defined in 2. section six of BS EN 13201-2 the requirement of these classes

Horizontal illuminance

Ēa (min. maintained) 1x

Additional requirement if facial recognition is necessary

Em in (maintained) 1x

Ev,min (maintained) 1x































performance not determined

performance not determined



Esc,min (maintained) 1x

i 0,2

To provide for uniformity, the actual value of the maintained average illuminance shall not exceed 1,5 times the minimum Ē value indicated for the class


This value in EN13201-2 table 3 is different to the value given in CIE 115:2010 table 7 and CEN is planning to issue an addendum to EN13201:2 to ensure the values in the two tables are the same

Table 1. The P lighting classes

Lighting Journal October 2016

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22 Pedestrians and urban lighting that perhaps the time spent looking at the pavement is not necessarily all used for doing critical visual tasks. To look at this in more detail we studied the time spent looking at the pavement on different sections of the route. The results are shown in Figure 2. The interesting thing in this chart is that on the accompanied part of the route, where there were fewest obstacles and there was the most light, there is more time spent looking at the pavement than on the other parts of the route, where there were more obstacles. This reinforces the point that the time spent looking down at the pavement is not all associated with visual tasks, and it may be considered that a significant part of the time spent looking down is governed by time taken to look at other things in the environment and the subjects look down during the time left over.

is given in Table 1 reproduced on the previous page. It this latest version of the standard there is now an optional requirement for vertical and semi-cylindrical illuminance. The selection of lighting classes, and the requirements necessary to demonstrate compliance to the class selected, 3 are covered in the UK standard BS 5489-1 . This however predates the current version of EN 13201-2 and thus there as yet are no recommendations for the UK on how to apply these new vertical and semi-cylindrical values. UNDERSTANDING THE REAL NEEDS OF PEDESTRIANS To start to understand what pedestrians actually need from road lighting we have been conducting research trying to find out what they actually look at. This work has been fully 4 reported in the journal Lighting Research and Technology . In this study, we asked a series of subject to walk a predefined route whilst wearing an eye tracker. This permitted us to see exactly where the centre of their visual field was at any given time. By careful selection of the route used we could ensure that the walk covered roads lit to three different lighting classes. Section of route

Lighting class

RE-ANALYSIS OF THE EYE TRACKING VIDEO More recently we have looked again at the videos in order to understand in more detail what people look at and the differences between what pedestrians look at during the night and what they look at during the day. To do this we needed to understand exactly where people were looking in terms of direction rather than simply what they were looking at. This was a much more complex assessment, as the video images were not taken in a fixed frame of reference as the subjects turned and tilted their heads as they walked along. In this part of the study we extracted ten still images from every second of video. We then measured the co-ordinates of the point of fixation and the point at eye height on the centre of the footpath, and the angle of tilt of the notional horizon. This process was quite simple; the problem was that we needed to look at a total of 44,528 images. From the measured data we could calculate the angular position of the gaze direction with respect to the axis of travel along the street. We then divided up the visual field into squares that were 1° by 1° and counted how many times the subjects looked in that direction and thus we could work out the percentage of time that subjects spent looking in a particular direction.

Obstacle density

Part 1



Part 2






Table 2. Properties of the sections of the route used

Table 2 summarises the parts of the route. At the end of the experiment we reviewed the videos and the analysis was focused on how much time was spent looking at particular surfaces. A summary of the amount of time looking at various things across all three elements of the route is given in Figure 1 reproduced below. The initial finding here is that for about half of the time the subjects were looking at the pavement. However, they spent less time looking at the pavement at night than during the day. This difference between day and night is an indication Night


80% 70%






Observed Duration

Observed Duration
















Figure 1. Percentage of time looking at different things

Lighting Journal October 2016


Transient Objects


Route 1

Route 2

Accompanied Route

Figure 2. Time spent observing the pavement on different sections of the route

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24 Pedestrians and urban lighting

Figure 3. Where people look in the day

REFERENCES Van Bommel W. J. M., Caminada E., Considerations of the lighting of residential areas for non-motorised traffic, CIBSE National Lighting Conference 1982 2 BS EN 13201-2: 2015 - Road Lighting Part 2: Performance Requirements 3 BS 5489-1:2013 Code of practice for the design of road lighting. Lighting of roads and public amenity areas 4 N Davoudian and P Raynham , What do pedestrians look at at night? Lighting Research and Technology, December 2012; vol. 44, 4: pp. 438448., first published on February 8, 2012


Figure 4. Where people look at night 0.72% - 0.80% 0.32% - 0.40%

0.64% - 0.72% 0.24% - 0.32%

0.56% - 0.64% 0.16% - 0.24%

0.48% - 0.56% 0.08% - 0.16%

Comparing the two set of results, it is clear that during the night pedestrians tend to focus more on what is directly ahead and there is a significant drop in looking to the sides close to the horizon. WHAT IS GOING ON? We need to understand why the pattern of fixations is different at night compared to the day. To start with it is necessary to understand the way peripheral vision drives eye movement. Peripheral vision is very good at detection objects and movement, but it is very poor in giving detailed information about an object. Thus our visual system responds to significant objects detected in the peripheral field by turning the central field towards the detected object, so that detailed information about the object can be obtained using the fovea, the highly spatially sensitive part of the central retina. Thus, for a subject to look at an object it is necessary for it to be detected in the peripheral field and the object must be assessed and being sufficiently salient. This tells us at night that objects in the peripheral field on the horizon line, but

Lighting Journal October 2016

0.40% - 0.48% 0.00% - 0.08%

separated from the direction of travel by more than about 15°, in general are less salient – and thus looked at less frequently. WHAT COMES NEXT? We know that there is a problem at night with the saliency of objects in the peripheral field and the most likely cause of this problem is the relatively low level of vertical illuminance at night on surfaces that run parallel to the axis of the street. So, our next step is to go back to our videos and note the objects that are looked at during the day and see if they are looked at during the night. We can then go and measure the luminance and contrast of the objects during the day and night and work out how much the vertical illuminance needs to be increased so the objects become salient during the night. Peter Raynham is course director of the MSc in light and lighting at the Institute for Environmental Design and Engineering at University College London. Navaz Davoodian is senior research associate and teaching fellow at the institute






26 Education and apprenticeships

EARN TO LEARN Six months from now all employers with a pay bill of more than £3 million will start paying into the government’s new apprenticeship ‘levy’. With ministers providing an update to their plans in August, what do we now know? Nic Paton reports


ike it not, it’s coming. Six months from now – from next April – employers will be expected to begin paying the new apprenticeship ‘levy’, the central plank of the government’s ambitious reform programme for apprenticeships and vocational training. While more detail is expected to be announced this month and in December, the Department for Education (DfE) in August added some significant flesh to the bones of its plans with the unveiling of two documents: proposals for how its new funding model for apprenticeships might work, and further details on the levy itself. So, what’s going to be happening? Essentially, from April 2017, any employer from across the UK with a pay bill of more than £3 million a year will be required to contribute to the levy which will, in turn, be put towards a new funding mechanism for apprenticeships in England that will kick off from May 2017. The levy will be charged at a rate of 0.5% of your annual pay bill. However,

Lighting Journal October 2016

there will also be a ‘levy allowance’ of £15,000 per year that an employer will be able to offset against the amount of levy paid. The levy will be paid to HM Revenue and Customs (HMRC) through the regular Pay as You Earn (PAYE) channels and will be levied (as it were) on a monthly basis. If, as an employer, you have calculated that you will pay the apprenticeship levy, you will need to declare this and include it in your usual PAYE payment to HMRC by the 19th (or 22nd if you report electronically) of the following month. Therefore, the first submission in which you will need to declare that you will pay the levy will be in May 2017. Unfortunately, the levy will not be allowable for corporation tax purposes. DIGITAL SYSTEM That’s all relatively clear enough. But the next obvious question is what happens to this money when you’ve paid it and how can you get it back to pay for training or apprenticeships?

According to the DfE document, once an employer has declared it has paid the levy to HMRC it will then be able to access funding for apprenticeships through a new digital apprenticeship service account. This, regular readers of Lighting Journal may recall (Lighting Journal March 2016, vol 81, no 3), is the online portal the government is setting up through which employers will be able to select the most appropriate apprenticeship for them, choose a training provider and then pay for the training. Payment will all be done digitally, through a ‘digital voucher’ scheme that has been compared to how you enter a discount code for an Amazon voucher or similar. You register your details, get your code, enter it and then redeem it to make payments to your learning provider, which in turn will reclaim the value of the voucher back from the Skills Funding Agency. Although, technically, this portal was supposed to be up and running from this month, according to the latest document employers will only

now be able to register to create their account from January onwards. Once you’ve registered, you’ll need to verify your PAYE schemes and link them to your account. The good news (sort of) is that, while employers will now be expected to be stumping up some of their hardearned cash to pay for apprentices, they won’t be expected to be paying for all of the cost of this training. Within its proposals, the government outlined that it will apply a 10%

The levy will be charged at a rate of 0.5% of your annual pay bill. However, there will also be a ‘levy allowance’ of £15,000 per year that an employer will be able to offset against the amount of levy paid monthly ‘top-up’ to the levy funds an employer pays in, for apprenticeship training in England. This should mean, the DfE has said, ‘for every £1 that enters your digital account to spend in England on apprenticeship training, you get £1.10.’ Funds will expire 18 months after they enter your digital account unless they have been spent on apprenticeship training. This will also apply to any top-ups. However, funds will be used on a ‘first in, first out’ basis meaning that, whenever a payment is taken from the digital account, the funds that entered your account first will be used first. The digital account will also let an employer know when any funds are due to expire, the DfE has said. Groups of employers will be able to come together and collect funds into one digital account. This will have to be done by registering to have the different PAYE schemes attached to a single digital account. The fact the system is all digital means employers should have a better handle on the funds they have already

paid, the funds they have available, and the price that they’ve agreed with their training provider, the DfE has argued. The expectation is that by 2020 all employers will be using the digital apprenticeship service to pay for training and assessment for apprenticeships. BUYING TRAINING OK, so your account is set up, your money’s all in. What now? When you agree to buy apprenticeship training from a training provider and the apprenticeship has started, monthly payments will be automatically taken from your digital account and sent to the provider. This, the DfE has argued, will spread the cost of the training over the lifetime of the apprenticeship. ‘The new system will pay providers one month in arrears for training they report has been delivered. This means that the first payments to leave your digital account, for training purchased in May, will be in June,’ the DfE has said, by way of example. ‘When you buy apprenticeship training through the digital apprenticeship service you don’t need to have enough funds in your digital account to cover the entire cost of the training at the start. As payments are taken from the digital account monthly, you just need to have enough funds in your account to cover the monthly cost of each apprenticeship you have chosen. You will see funds entering your digital account each month as you pay the levy, and funds leaving the account regularly each month as you pay for training,’ it has added. If you don’t have enough in your account in a particular month, you will be asked to make a contribution to the extra cost of training and to pay this directly to the provider, rather than through your digital account. Employers that don’t come under the remit of the levy – normally because they’re smaller (in other words their pay bill is below £3 million a year) – won’t need to use this digital service immediately. The likely start date for bringing smaller employers into the frame is 2018 onwards, the DfE has estimated. Smaller employers that are not paying the levy will still be required to ‘co-invest’ a proportion of the cost of training – currently the plan is 10% – but the government will stump up the other 90%. Very small employers (employing fewer than 50 people) will

KEY POINTS • • Despite requests from many within industry for a delay, the government has said it intends to go ahead with introducing the levy from 6 April next year, with new funding mechanisms coming into play a month later. • • You will need to pay the levy if you are an employer with a pay bill of more than £3 million each year. It will apply to employers across the UK, not just in England. • • The levy will be charged at a rate of 0.5% of your annual pay bill. There will be a ‘levy allowance’ of £15,000 per year to offset against the levy you pay. It will be paid to HMRC through regular PAYE processing. • • The levy allowance will operate on a monthly basis and will accumulate throughout the year, meaning it will be, in effect, an allowance of £1,250 a month. Any unused allowance can be carried from one month to the next. • • Once you have declared your levy to HMRC, you will be able to access funding for apprenticeships through a new digital apprenticeship service account. • • The government will, however, apply a monthly 10% ‘top-up’ to the funds employers have for spending on apprenticeship training in England. • • Employers that do not pay the levy, but would like to train an apprentice, will be required to ‘co-invest’ 10% of the cost of the apprenticeship training and assessment, with the government paying the remaining 90%. However, very small firms (employing fewer than 50 people) aiming to train young apprentices (aged 16-18) will be exempt from this requirement. • • The government ran a short consultation on the plans between August and September. More details are due to be announced this month (October) on final funding levels, rules and the finer details of government support. There will be further guidance for employers from HMRC in December on how to calculate and pay the levy. • • Full details of the government’s proposals can be found on the Department for Education’s web page within the government portal,

Lighting Journal October 2016

28 Education and apprenticeships

EXAMPLES The Department for Education outlined some examples of how the levy might work in practice.

For an employer with an annual pay bill of £5 million. Levy sum (0.5% x £5,000,000) = £25,000 Minus levy allowance (£25,000£15,000) Total: £10,000 annual levy payment For an employer with an annual pay bill of £2 million (meaning it does not have to pay the levy). Levy sum (0.5% x £2,000,000) = £10,000 Minus levy allowance (£10,000 – £15,000) Total: £0 annual levy payment

be exempt from even this – as long as they’re taking on young apprentices aged 16-18 – and so, effectively, their training needs will be completely subsidised. There will also be a system of grants available to soften the financial blow for the smallest employers.

Lighting Journal October 2016

Small employers will get £1,000 as an incentive if they take on 16- to 18-year-old apprentices, with training providers getting another £1,000. This, as it stands, appears to be similar to the existing Apprenticeship Grant for Employers, which is currently worth up to £1,500 for small firms to help with the cost of their first five apprentices aged 16-24. But there are still details to be confirmed on this. DEVOLUTION QUESTION Finally, given the levy will apply to all employers but the new digital service will only be for apprenticeships in England, what will this mean for employers in the other countries of the UK? The idea previously mooted has been that the government will distribute a share of the levy fund to the home nations other than England. However, in the current document, the DfE has remained somewhat vague about this, simply arguing: ‘Apprenticeships are a devolved policy, which means that authorities in each of the UK nations manage their own apprenticeship programmes, including how funding is spent on apprenticeship training. ‘The digital apprenticeship

Very small employers (employing fewer than 50 people) will be exempt from ‘coinvesting’ – as long as they’re taking on young apprentices aged 16-18 – and so, effectively, their training needs will be completely subsidised service will support the English apprenticeship system. Scotland, Wales and Northern Ireland have their own arrangements for supporting employers to access apprenticeships.’ Hopefully more detail on this issue, among others, will become clear in the expected announcements by the government later this month and in December.

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30 Connected lighting


A stretch of the A143 through the Suffolk village of Great Barton is hosting a pilot connected lighting scheme that, it is being argued, has the potential to transform the economics of smart city applications. Lighting Journal took a look

But the savings come from selectively reducing light output when it is not needed. Lighting empty roads in the early hours on full power is, of course, in no-one’s interests, not least the taxpaying public. Based on these savings, a connected street lighting system, including the wireless network, pays for itself in just a few years. One of the benefits of connected street lighting that isn’t in a typical business case is the ability to remotely adapt lighting levels. This is used today

to brighten lighting to assist emergency services or for special events. But it is also useful to fine-tune LED lighting in residential areas. The public reaction to LED street lights is notoriously difficult to predict, and typically varies street by street, with some residents complaining about glare and others about gloom. Without central control the only response is to manually visit and reset each light, wiping out much of the initial LED energy savings. Connected street lights


s most lighting professionals will full well know, the primary business case for connected street lights is relatively straightforward, and is one based very much on maintenance and energy cost savings. Without connected street lights, the only way to ensure lights are working is through regular night patrols. Connected street lights, on the other hand, alert when they are not working; they provide important diagnostics that ensure a first-time fix and can even warn of potential problems before they occur. The result, naturally, is a much more efficient maintenance and upgrade operation. Energy savings include more accurate on/off timing and adapting the light output to compensate for age degradation and cleaning intervals.

Lighting Journal October 2016

The lighting column-mounted sensor is measuring traffic volume but is also a gateway for other sensors

Connected lighting 31 therefore allow a constant refining of lighting programmes over time, at an ultra-local level. VARIABLE TRAFFIC PATTERNS All of which brings us back to the system in Great Barton. What is being tested in this Suffolk village is a hybrid system that combines connected street lighting with multiple sensors across a smart city data hub, all using an open data standard. The lighting controls company behind the project is Telensa, working with BT. Suffolk County Council already has a longstanding relationship with Telensa, having connected its 60,000+ street lights several years ago using the company’s PLANet wireless Central Management System (CMS). As Richard Webster, street lighting manager at Suffolk County Council, has put it: ‘As a pioneer of connected street lighting we’re always looking for new ways to make lighting a better experience for citizens and better value for taxpayers. This pilot integrates traffic sensors to automatically deliver the right light at the right time.’ To that end, the LED street lights along the main road (A143) are centrally set by PLANet gradually to dim after 9pm, when traffic levels typically subside to a low level. But, like many roads, traffic patterns are variable. The council was therefore looking for a more dynamic setup that would provide the best balance between energy efficiency and safety. The solution has been to combine PLANet with the BT Sense ‘Smart City’ services suite. Commissioned by BT and using street light-mounted multi-sensors, the unit consists of a video camera and a compute platform running video analytics to count the number of vehicles passing per minute in each lane. No video is stored or transmitted, just the vehicle count number is sent to the Cloud-based BT data hub. The PLANet algorithms look up the

As a pioneer of connected street lighting we’re always looking for new ways to make lighting a better experience for citizens and better value for taxpayers. This pilot integrates traffic sensors to automatically deliver the right light at the right time traffic count from the BT data hub and, from that, decide whether to over-ride the timed dimming program. PLANet only communicates with the street lights if a change is needed, and the override only lasts until the next scheduled programme change. This means that, in the event of a network outage, the street lights will simply return to their normal scheduled programme. Of course, adaptive street lighting isn’t new. But what’s different about this pilot is that, instead of the system requiring time-consuming and costly custom integration, the interfaces between the BT data hub and PLANet are built to the Hypercat standard. Hypercat is the UK-developed open standard for the integration of smart city technologies. It allows disparate systems to interact and exchange data using standard, familiar internet technologies. This means it is easier for sensor and

application developers to integrate with other systems, and so reduce the time and cost of doing so. In the case of the trial at Great Barton, it meant BT developers did not need to know anything about the intricacies of PLANet, while the PLANet developers just accessed the traffic data in a standard format. INTEGRATION COSTS Smart cities of the future will be an array of countless sensors, actuators and systems from many vendors. Open interfaces such as that being tested at Great Barton are therefore potentially an example of how hybrid applications can be built to deliver business and social value without incurring crippling integration costs. So, what’s next? Clearly, part of ‘what’s next’ will be simply assessing and evaluating the pilot as it stands. But one area being examined is the fact the traffic sensor is more than just a camera and a processing unit. It is measuring average speed, and acts as a gateway that other sensors can connect to; it is being used to measure noise, SO2 and NO2 pollution, as well as temperature and air pressure. This illustrates the potential at least for street lights to act as low-cost hosts for sensors, and the potential street light remote control systems could have in terms of dynamically mapping data. A further area of potential value is the data beyond traffic volume that can be derived from the camera. You could, for example, count and interrogate the different types of traffic – the mix of trucks, vans, cars, bikes and pedestrians and so on. This, in turn, would allow adjustment of lighting levels according to the type of traffic, for example turning it up if there was a certain level of cycle traffic or of pedestrians on the pavement. Such ‘ultra-local’ data could also help with traffic planning, not to mention be a potential source of revenue for local authorities in cash-strapped times.

Lighting Journal October 2016

32 LuxLive 2016


Emergency lighting will be firmly in the spotlight at next month’s LuxLive. Lighting Journal took a look at what lighting professionals can expect


ore than 8,000 lighting professionals are expected to descend on London’s ExCel centre on 23 and 24 November for this year’s LuxLive lighting show and exhibition. There will some 300 exhibitors at the show, which is supported by the ILP, as well as a plethora of speakers and presentations to choose from. So, what can lighting professionals expect? One new feature to look out for this year is The Escape Zone, a theatre dedicated to emergency lighting. To that end, there will be an array of presentations over the two days devoted to common emergency lighting questions, challenges and opportunities. For example, there will be sessions on ‘Is my emergency lighting compliant?’, a battery masterclass, a presentation on the particular challenges associated with emergency lighting in heritage buildings and an expert panel debate, to cite just a few of the emergency lighting-themed events scheduled in. CONNECTED LIGHTING Returning this year after making its debut at LuxLive in 2015, will be the Internet of Things (IoT) Arena. This will be an open-plan arena devoted to all things connected lighting, including internet-enabled controls and building management. Again, there will be a huge amount of content to choose from, but topics being covered this year include IoT security, the reality of a wireless network, lighting’s role in smart buildings and the likely role of street lighting within smart cities. There will also be two Tech Theatres running practical sessions on a range of topics, including warranties, financing, latest standards and codes of practice, among many others. As in previous years, presentations have themed so that key sectors are covered each day. On the Wednesday, for example, the focus will be on lighting for retail, hospitality, office, education and healthcare. On the Thursday, the focus will be more industrial, outdoor and transport lighting. Among a wide-ranging programme of presentations and events, the KEY INFORMATION What: LuxLive 2016 When: 23-24 November Where: ExCel centre, London Doors open: 9am Where to find out more: • LuxLive: • • Strategies in Light Europe:

Lighting Journal October 2016

main Lux Arena will once again host the Bad Lighting Awards, with aim of casting ‘a badly-aimed spotlight on retailers, restaurateurs and other high-street names who are getting it wrong’. More positively, the SLL Young Lighter on the Year will also be named in the arena on the Thursday morning. Finally, LuxLive will once again be running alongside the lighting design market, ‘where lighting meets architecture’, and which is this year hosting some 40 exhibitors. As well as lightspace.London, the Strategies in Light Europe conference will also be taking place across the two days.


TO GAME CHANGER 1978 - 2016

Dextra Group are rewriting the lighting rule book. Find out more at Lux Live 2016, stand H20.




34 Legislation


The EU’s ban on inefficient directional halogen lamps came into effect last month, meaning directional (reflector) mains voltage halogen lamps such as GU10, R63 and R50 are no longer allowed to be placed on the market. But this will create its own challenges around LED dimming, warns Sam Woodward


rom last month (1 September), the European Commission’s ban on inefficient directional halogen lamps came into effect. This means there will be a lot of GU10 sockets, for example, into which LED replacements will now be fitted. For many people, this will not be a smooth process: LED lighting is very prone to flicker and instability when dimmed, because the LED chips themselves react so quickly to changes in the electricity supplied to them. Whereas with more traditional light sources, such as incandescent lamps, it was normal to swap lamps from different manufacturers and to expect similar behaviour, that’s no longer the case with LEDs. Instead it is now crucial to consider compatibility between each part of the whole LED system; the lamps, the dimmers and the drivers which supply power to the LEDs themselves. Here’s my top ten hints to help lighting professionals achieve success with LED dimming.

1. All LED systems have a driver: the electronics that converts the incoming AC mains voltage into the lowvoltage DC which the actual LED chips require. For mains-dimmable lamps the components to achieve this are usually hidden away inside the lamp, often located in the stem, or as a small internal PCB. For LED fixtures this is often a remote-mounting box, joined by a short cable to the ‘light engine’. The compatibility of the driver and the dimmer is the crucial element in determining smooth-dimming, flicker-free success in an LED project. 2. Remember that not all LED lamps are created equal – different models will perform very differently, even when connected to the same type of dimmer. Even different lamp SKUs from the same manufacturer may give very different results, despite looking similar from the outside. And, of course, some lamps are not dimmable at all. That information is often buried in the small print on the

GU10 halogen lamps, which are often popular as ceiling spots, will gradually need to be replaced with LED

Lighting Journal October 2016

Legislation 35

Whereas with more traditional light sources, such as incandescent lamps, it was normal to swap lamps from different manufacturers and to expect similar behaviour, that’s no longer the case with LEDs. Instead it is now crucial to consider compatibility between each part of the whole LED system; the lamps, the dimmers and the drivers which supply power to the LEDs themselves

packaging and is therefore easy to miss. Make sure you only use lamps that have been tested to show they are compatible with the dimmer you’re using. 3. ‘Minimum load’ is an issue on many older dimmers, but not all. Some dimmers require at least 40W of load in order to work, whereas newer dimmers, designed specifically with LED in mind, may not have this restriction. Depending on the internal design of the LED lamp you may achieve success with older dimmers, but the only way to know this for sure is to properly test the combination of lamps and dimmer. 4. A well-designed dimmer will have a setting known as ‘low-end trim’. This is the minimum power level at which the dimmer will first switch on the lamp. For those lamps which suffer from flicker problems at the lower end of the dimming range this setting can ensure that they are never dimmed into this ‘unstable range’, thereby avoiding flicker issues. 5. The lowest stable brightness level will vary considerably between different lamp models, in other words some lamps are better at being dimmed lower than others. The lighting industry usually uses ‘measured power’ to describe dimming levels, for example 1%, 5% or 10%. However, ‘measured brightness’ and ‘perceived brightness’ are not the same thing: the pupils of our eyes open up at low light levels to let more light in, and therefore we see small brightness changes at low levels more clearly. Be aware, therefore, that a lamp + dimmer combination

Lighting Journal October 2016

36 Legislation

that can dim down to 10% power will still look as if it’s at 30% brightness. To achieve a 10% perceived brightness, you’ll need to find a combination that can dim as low as just 1% measured light, which narrows your choice of lamp vendor considerably. We, for example, list both the minimum power and the perceived brightness achievable with each lamp tested on our LED report-cards. 6. There are some LED lamps are compatible with leading edge dimmers, and some are compatible with trailing-edge dimmers. Some more advanced dimmers, known as ‘phase-adaptive’, can perform either way round, meaning a wider selection of lamps will be compatible. Proper testing, with the right equipment, is the only way of knowing which option to use. 7. For lamps that are dimmed using the leading-edge method there will be an effect known as ‘repetitive inrush current’ on each half-cycle of the chopped-up mains input to the lamp. The quantity of lamps which can be connected to any one dimmer will be determined by the total size of this inrush, along with the total wattage of the load. The only way to determine the safe maximum permitted quantity of lamps is by measuring the repetitive inrush current, during testing. The quantity of lamps that can be connected to one dimmer can vary very widely indeed: you can often halve or double the permitted quantity simply by choosing a different lamp. 8. Mains dimming isn’t the only option for dimming lamps, although in a retrofit scenario it is likely to be the first choice.

Lighting Journal October 2016

There are other types of LED driver, which do not take a chopped-up incoming mains supply in order to dim them, but instead use a fixed mains supply with a low-voltage signal to indicate the required output brightness. These low-voltage signals use a protocol such as 0-10V, DALI or DMX. Generally, you’ll experience more success in using this type of system because the mains supply to the driver is not chopped up, but be aware of the cabling requirements. 9. Why dim lamps? There are two answers. Firstly, dimming LEDs, in other words reducing the amount of power going through them, will lower the LED chips’ ‘junction temperature’, which in turn will increase the lifetime of the LED, thereby reducing maintenance cycles. The other answer is far more aesthetic: dimmed light creates an atmosphere and reduces energy usage. 10. Focus on compatibility testing. For example, since 2009 we’ve had a team of engineers dedicated to testing compatibility between LED lamps and dimmers. The resulting LED report cards give details of the minimum and maximum number of lamps that can be connected to each dimmer zone, along with the minimum and maximum output power, and the resulting perceived low-end level which can be achieved. Sam Woodward is customer education leader at Lutron and co-author of the Institution of Engineering and Technology’s Code of Practice for the Application of LED Lighting Systems

Inside the ILP: obituary 37


Former Institution President Joe Woodhouse sadly passed away in July. Bob Stevenson looks back at his life and career while, below, Richard Ryan adds his recollections about how Joe inspired him to become a lighting professional


oseph (Joe) Woodhouse, former chief lighting engineer for Sheffield and past President of the Institution died peacefully at home on 19 July, aged 97 years. Joe was happily married to Kathleen for 65 years until she died in March 2011. He was dad to four children, granddad to eight and great granddad to seven. The Scouts and the Unity Church were ‘the critical factors’ in Joe’s life, which resulted in Joe becoming a scout leader and a lay preacher. WARTIME MEDICAL TRIALS He was one of a number of conscientious objectors during World War Two who volunteered to work with the Sorby Institute in Sheffield, under the leadership of Major Dr Kenneth Mellanby. There they were used as human guinea pigs to try to identify the causes and possible cures for scabies, which affected many soldiers. Joe started his career with Sheffield City Lighting Department as a clerk. In those days, the high priority in the lighting department was keeping account of gas mantles and the work of the ‘knocker up’, whose duties were to get lighting department workers to start work on switching gas and electric lights on and off. After rising to the position of deputy engineer in the late 1940s in Sheffield, Joe became lighting engineer for Derby between

1951-1960, before returning as chief to Sheffield between 1960-1974, and then finishing his career with South Yorkshire County Council from 1974-1980. Joe was responsible for the introduction of low pressure sodium lighting in Sheffield, which culminated in the final disappearance of gas and tungsten filament lighting within the city. He masterminded the engineering side of the famous Sheffield Christmas lights in the 1960s, beginning with second-hand castoffs from London’s Regent Street and the Blackpool Illuminations. HIGHLY RESPECTED He pursued the professional side of his career through membership of the Association of Public Lighting Engineers (APLE) (now, of course, the ILP), taking on a variety of roles, including that of Treasurer, before being elected President in 1971. Joe was a highly respected member of the lighting profession and always prepared to help other people; even after retirement he carried on encouraging engineers to further their careers by helping to run lighting training courses for them. Joe was described by one of his grandchildren as the ‘kindest person I know’ – an apt summary for a highly respected member of the lighting profession.



would just like to add how sad I am to hear about the passing of Joe Woodhouse – a man who had a massive impact on the Blackpool Illuminations. Yes, that was not a typo, I say Blackpool Illuminations as, without Joe and his contemporaries, the amazing spectacle that was Sheffield’s Christmas lights in the 1960s would not have inspired the son of a hoover salesman in a Sheffield suburb to dream, aged seven, that he wanted to be a part of Blackpool’s famous annual illuminations jamboree. I met Joe in back in 1999 when I still had hair, glasses like Dennis Taylor and less excess weight hanging over my trousers. While they say ‘never meet your heroes’ in Joe’s case this was 100% wrong. He was charming, witty and still had a passion for his subject. SOURCE OF PRIDE Despite the difficulties in dealing with winds and rain, Sheffield’s lights were at that time unquestionably the best in the country, and were a massive source of pride to the muchbombed city. Joe was a fantastic representative of our profession; inspirational and truly dedicated. He was a genuine role model for anyone who wanted to be good at their job and, above all, he was a genuinely lovely chap. I was so lucky to study his work and learn from him and am proud to this day of that association. Joe – thank you. Richard A Ryan is head of Blackpool Illuminations

Above: Former President of the Institution Joe Woodhouse early in his career, and during his retirement Below: Sheffield Illuminations 1965

38 Legal issues


Legal issues 39

The uncertain economic climate since June’s ‘Brexit’ vote could mean a rise in payment and contract disputes. The Construction Act, which is 20 years old this year, is one of the key pieces of the law lighting professionals can use to protect themselves. Howard Crossman and Kirstie Sowter look at how it has changed over the years


ighting is generally seen as part of the construction industry. Therefore, stipulations regulating procedures in the construction industry are very relevant to lighting. Central to this is the Construction Act, which covers payment procedures and the adjudication process. Experts predict a slump in new projects following the aftereffects of Brexit, creating a fertile ground for arguments on payment issues and disputes. We, therefore, thought it was good timing to drill down into the Construction Act and explain key provisions and some of the changes over the years. This year marks 20 years since the inception of Part II of the Housing, Grants and Regeneration Act 1996 (the ‘Construction Act 1996’), in effect, the original Construction Act. Changes to the Construction Act 1996 came into force in October 2011 following the implementation of the Local Democracy, Economic Development and Construction Act 2009 (the ‘Construction Act 2009’) and we cover this below. DOES THE CONSTRUCTION CONTRACT HAVE TO BE IN WRITING? As its name suggests, The Construction Act only applies to construction contracts. The Construction Act 2009 removed the requirement for a ‘construction contract’ to be in writing in order for a dispute under such a contract to be referred to adjudication. Therefore, there has been a real surge in disputes arising under oral construction contracts becoming the subject of adjudications and enforcement claims in the Technology and Construction Courts (known as the TCC). Of course, best practice remains to ensure any lighting contract is agreed in writing before the start, although prioritising drafting and agreeing a written document often slips through the net and getting started takes priority! THE SCHEME FOR CONSTRUCTION CONTRACTS The Construction Act 1996 also dealt with multiple issues relating to payment under a construction contract, including payment mechanisms and notices, default payment notices and pay less notices. The Construction Act 1996 (and amended Construction Act 2009) are supplemented by the Scheme for Construction Contracts (England and Wales) Regulations 1998 (commonly known as the ‘Scheme for Construction Contracts’). It is a statutory requirement for every construction contract to include provisions with regard to payment and, if it fails to do so or provides contrary provisions, then the relevant clauses of the Scheme for Construction Contracts fill in gaps and/or take the place of contrary provision/s.

PAYMENT PROVISIONS The Construction Act 2009 made a number of changes to the payment provisions: Staged payments – Section 109(1) of the 1996 Act gave a party the right to payment by ‘instalments, stage payments or other periodic payments’ for any work under a construction contract if the duration is specified to be more than 45 days. The 2009 Act made a minor change, namely to change ‘under the construction contract’ to ‘provided for by the construction contract’ to ensure consistency with some of the new provisions (see below). Payment mechanisms – Section 110(1) of the 1996 Act required every construction contract (irrespective of the duration) to provide an adequate mechanism to calculate: (i) the due date, (ii) sums due and (iii) the final date for payment. The 2009 Act amended this section and introduced several new sections and definitions including: (i) Payee: ‘the person to whom payment is due’, (ii) Payer: ‘the person from whom payment is due’, (iii) Payment Due Date: ‘the date provided for by the contract as the date on which the payment is due’, and (iv) Specified Person: ‘a person specified in or determined in accordance with the provisions of the contract’. Conditional payments – Section 113(1) of the 1996 Act prohibited pay-when-paid clauses, but did not prevent paywhen-certified clauses (for example where the adequate mechanism for payment was linked to obligations under another head contract). The 2009 Act changed this to ensure pay-when-certified clauses were also banned. Payment notices – In order for a payment notice to be valid, it must state: (i) the sums due, (ii) how that sum is calculated and (iii) is issued within the correct timescale. A payment notice must be given, even if the sum due is zero. Payment of notified sum – The 2009 Act replaced Section 111 of the 1996 Act was with a new one. This provision requires the paying party to pay the ‘notified sum’ (the sum specified in the payment notice) by the final date for payment. This was a major change from the original Section 111, under which paying parties who wished to withhold payment of any sums due had to serve a withholding notice. Pay less notices – Section 111(3) allows the paying party to pay less than the notified sum (set out in the payment notice), providing the paying party gives a notice: (i) setting out the basis of the calculation for the amount specified in the pay less notice and (ii) that is served within the prescribed period (usually seven days) before the final date for payment. If the contract does not clearly set out these requirements, then the relevant provisions of the Scheme for Construction Contracts are implied into the contract. SUSPENSION FOR NON-PAYMENT Both the 1996 Act and the amended 2009 Act set out provisions for non-payment in breach of the payment requirements set out above. In a construction contract, an unpaid party has a statutory right to suspend performance for non-payment. That right is set out in section 112 of the 1996 Act. However, it is important to note this the right to suspend only applies where: • There has been a non-payment and not for any other type of breach under the construction contract • If the notified sum is unpaid after the final date for payment • The unpaid party has served notice to the defaulting party before it suspends some or all of its obligations under the contract This gives the unpaid party a right to suspend performance of ‘any or all’ of its obligations under the contract. Before the

Lighting Journal October 2016

40 Legal issues changes brought by the 2009 Act, the unpaid party could only suspend performance of ‘his obligations under the contract’ (usually interpreted as ‘all’ obligations under the contract). The option to suspend only some of the works allows lighting contractors and consultants the ability to strategically manage a non-payment issue without blowing up the whole project. However, in lighting, parties are less likely to suspend any of their work or services unless absolutely necessary because of the impact such a step may have on the commercial relationship with the rest of the project team. Working together in collaboration is not compatible with downing tools and suspending unless absolutely necessary (not least because of the requirements above). THE ADJUDICATION PROCEDURE If payment is still not forthcoming, then the last resort may be to refer a dispute to adjudication. Below is the adjudication procedure summarised. Dispute crystallises Either party served a notice of intention to refer the dispute to adjudicaton The notice must identify the dispute and set out the remedy Within seven days of the issue of the notice, the referring party must serve upon the other party its referral (setting out a detailed explanation of its case along with supporting documentation)

Also within the same seven day period, the referring party must secure the appointment of an adjudicator (either being the named person or the nominating body named in the contract) The nominating body will usually charge a fee to be paid by the referring party Following his appointment, the adjudicator will set out a timetable. This will usually permit the other party to issue a response to the referral, for the referring party to reply to that response and for the other party to issue a rejoinder to that reply

The adjudicator must make his decision within 28 days of the referral (that can be extended by an additional 14 days with the permission of the referring party)

The adjudicator’s decision will be binding on the parties (and enforceable by the TCC) unless the adjudicator has acted outside of his jurisdiction or was biased

There is no appeal process. However, the parties can take the same dispute to litigation

WHAT IS THE ‘SLIP RULE’? A further change brought by the Construction Act 2009 is to section 108(3A) of the 1996 Act, which introduced a statutory

Lighting Journal October 2016

slip rule that allows the adjudicator to correct a clerical, mathematical or typographical error arising by accident or omission. However, any request to amend a clerical error omission must be done so in reasonable time. An example of this is the case of YCMS Ltd (trading as Young Construction Management Services) v (1) Stephen Grabiner and (2) Miriam Grabiner [2009] EWHC 127. Mr Justice Akenhead confirmed that an adjudicator may address a ‘slip’ in a decision, but he must do so promptly and may only correct an error (rather than changing his mind). In this case, Mr and Mrs Grabiner employed YCMS to carry out extensive works at their property under a building contract in writing, which incorporated the JCT Intermediate Form. Substantial variations were issued under the contract which increased the contract sum to more than £1 million. Whilst the adjudicator found in favour of YCMS in respect of its first two adjudication referrals relating to a payment certificate and payment of additional preliminaries, he agreed with Mr and Mrs Grabiner in respect of the final certificate, which was also referred to adjudication. YCMS issued court proceedings to enforce the adjudicator’s decision in the TCC. Mr and Mrs Grabiner opposed enforcement on the basis that the adjudicator referred in his decision to a payment certificate that had not been included in the referral (but later emerged as part of Mr and Mrs Grabiner’s defence). In this case, the adjudicator had gone further than just correct his error and had decided to make a recalculation based on a different certificate. Mr and Mrs Grabiner were therefore materially prejudiced by the amendment. CONCLUSION The Construction Act 1996 and its subsequent amendments through the Construction Act 2009, working in conjunction with the Scheme for Construction Contracts, are designed to enhance the position of contracting parties (in the lighting industry) and seek to avoid cash-flow and insolvency issues. Disputes will, however, continue to arise in some shape and form. A steady trickle of reported cases in the TCC demonstrates there is still uncertainty in interpreting the legislation and the position continues to evolve. Furthermore, the current uncertainty with the economic climate in the UK creates fertile ground for arguments on payment and procedure. More than ever, there is increased focus on employers, local authorities, contractors, subcontractors, suppliers and consultants in lighting to deliver and for payments to be calculated correctly and paid on time – not least to avoid disputes. Kirstie Sowter is a solicitor and Howard Crossman (hcrossman@ is head of construction at Greenwoods solicitors LLP. With offices in London, Cambridge and Peterborough, Greenwoods is a UK commercial law firm providing legal advice and pragmatic solutions to local, national and international clients

Book review


‘A WELCOME ADDITION TO ANY BOOKSHELF’ The latest publication from LUCI highlights 15 innovative light art installations and how they have helped their respective municipalities to regenerate and transform their urban areas. Emma Cogswell is impressed Title: Light and Art in Public Spaces Pages: 70pp Author: LUCI Association Price: €23


ithout a doubt this book will appeal to the architectural lighting designer, town planner and anyone who is involved with lighting in the public realm. It is wonderfully set out in a landscape format with excellent photography. It is published by LUCI Light & Art Commission, chaired by the City of Gothenburg. The LUCI network has been growing since its inception in 2002, and one of its core goals is to put forward and explore the different areas in which lighting can make a difference to cities. The deputy mayor of Gothenburg states in the book that the goal was to illustrate and take advantage of the fact LUCI brings together individuals from a varied range of professions related to light and the city. From urban planners, to lighting engineers, to designers and artists; it is a mix of an individuals that work together with our public spaces and create memorable, useful and comfortable urban experiences for citizens and visitors alike. The book is broken in to four sections: creating light art installations in public spaces; using light to enhance public art; using light and art to enhance buildings and neighbourhoods; and using light and art to transform urban underpasses. It’s always important to set out why lighting is important; it may be obvious to those of us who work in this medium and even accepted by those who get to experience the end result, but the explanation is often needed to justify the expense. PUBLIC AWARENESS Light art can help to expand public awareness of city resources, promote tourism and bolster the local economy. With its unique ability to alter the way that space is perceived at night, light art has the potential to change popular attitudes about places in the city that are considered unsafe or unwelcoming. Light art has become more architectural in its nature. This could be due to changes in technology, which now enables designers and artists to create more fantastical scenes. LEDs and miniaturisation have given birth to more exciting creations built into the architectural fabric.

To that end, this book highlights 15 case studies within pioneering cities – Amsterdam, Gothenburg, Helsinki, Lyon, Rotterdam and Turin – that have been working with light and art as a key component in their urban planning strategy. Its aim is, as LUCI states, to give ‘municipalities and local authorities the tools to develop such light and art projects with artists and lighting designers: it describes the stakeholders and processes involved, main challenges faced and key factors of success’. One good example is Silo 468 in Helsinki, Finland, designed by Lighting Design Collective and inaugurated in October 2012, when Helsinki was the World Design Capital. The city decided to convert this silo into a light art structure in order to kick off the creation of a new residential area designed to attract 11,000 inhabitants by 2030. The idea is that it provides a focus for a previously relatively unknown area, creates a landmark and is a marketing device for the city. And this stunning project is so much more than making a building look pretty; it is a reminder of the past and a salute to the industrial heritage of the site.

I also particularly liked the section on using light and art to transform urban underpasses. As the book articulates, urban underpasses and tunnels are often ‘non-places’ or environments that the general public usually do not pay a lot of attention to. However, given the high frequency of their use, pedestrian tunnels are in fact important areas that have too long gone unaddressed. In addition, people often experience tunnels as unsafe places. Another installation highlighted in the book is ‘the Amphibious Tunnel’. This was a standard, rather unwelcoming, tunnel in Gothenburg, Sweden, until Kajsa Sperling added crystals into the walls at different heights.

POWER OF LIGHT AND ART These crystals slowly shift in light colour and intensity, which entices people to slow down and touch the walls. Large thermo plastic diamonds were painted at the exits between the inside and outside of the tunnel, almost intuitively inviting children and adults alike to hop on them. This project successfully proved that light and art can be powerful tools to get people to look PLACE AND PURPOSE at their environments differently and actively The public is encouraged to enter the building participate with the architecture. and experience the sanctum as well as enjoy its Such methods of citizen involvement can beauty from the outside. The project is open to have a positive effect on the wellbeing of people all citizens and provides a novel destination. It has won widespread appreciation and popularity, and urban space, as well as reduce damage and vandalism. collecting 12 international light art competitions. This book successfully brings together For me, it’s interesting to note the light art projects from Amsterdam, Gothenburg, works throughout the book often have this Helsinki, Lyon, Rotterdam and Turin. As well common theme: bringing purpose to a place, giving light the power to transform and bringing a as Silo 468 and the Amphibious Tunnel, the 15 examples highlighted in the book include new outlook to places. the Moodwall in Amsterdam, the Part-Dieu Often light installations, as we have seen with Library in Lyon, Light Gig in Rotterdam and Luci festivals such as Alingsås in Sweden, attract people to come and see the spectacle and even in d’Artista in Turin. It would be wonderful to see a second some cases be immersed in the lighting design. These visitors, naturally, boost the local economy edition that can include more of the beautiful cities and wonderful projects we have in in relatively simple ways: cafes sell more coffee, taxis are used etc. There is without doubt a sense other cities and towns across Europe. But, ultimately, this book is a welcome addition to of community and pride when such lighting any bookshelf. installations illuminate the cityscape.

Lighting Journal October 2016

42 Independent Light on the lighting past design

CENTRAL PLANNING Central Management Systems (CMS) nowadays offer the lighting engineer ever more control over his or her lighting stock. But CMS is not a new idea, and the concept of central control has bubbled through the literature since the earliest days of public street lighting. Simon Cornwell delved back into the archives


n the first decades of the 20th century, automatic control of individual lanterns was perfectly possible using either tried-and-tested time switches (now fitted with solar dials so they could adjust to the seasons) or fragile, selenium-based photoelectric cells. But the ability to control all the lighting at once was an easily identifiable need: what about unseasonable weather such as sudden fog or a heavy storm? What about part-time lighting where lamps would be extinguished in the early hours of the morning? And what about an early form of dimming where select lamps in multiple-lamped lanterns could be extinguished? As the 1930s progressed, and the threat of war became more palpable, the ability to quickly switch off the network became an urgent requirement The easiest, and most costly, centralised systems were achieved by physically connecting all the street lights together on their own dedicated network. An independent system of mains devoted to just the street lighting was one expensive solution and was used sparingly. Other systems utilised a ‘5th core’ or pilot wire to actuate relays in the street lights when either pulsed or turned on. All these systems required additions, or modifications, to the emerging electrical networks; but what the lighting engineers really wanted was

Lighting Journal October 2016

something that could be added more cheaply and simply to the existing network. DIFFERENT FREQUENCIES The solution was to broadcast signals through the network, which could be detected and acted upon by specialised units housed in each street light. Such signals would also be ignored and undetected by industrial and domestic equipment also connected to the network. Two competing systems emerged; one that injected high-frequency signals into the supply and one which altered the base voltage. Both required additional equipment to be installed in the substations, and individual detectors in each street light, but it was a small price to pay compared with a dedicated mains pilot wire or 5th core. Various manufacturers offered competing systems, but the most popular high-frequency based system was Rythmatic Control Equipment offered by the Automatic Telephone & Electric Company Limited. Different frequencies could be squirted into the network and these offered a discrete number of actions; the company initially offered ‘all on’, ‘half off’ and ‘off’ for street lighting but expanded the range to include support for actuating sirens as Air Raid Precautions (ARP) started appearing in the late 1930s, as fears about war intensified. The other system was DC Bias, where a fixed voltage was added or subtracted to the base voltage at the substation. Again, this would have made little difference to domestic or industrial equipment, which would’ve been designed for deviations in the supply, but it was just enough to trip sensitive receiver components in street lights. Therefore, varying the base voltage by battery-based equipment in the substation could offer an alternative CMS system. Standard Telephones & Cables Limited was the major manufacturer of this technology, and heavily promoted its system both before and after the Second World War on its simplicity and lower cost. Of course, the ever-resourceful gas manufacturers had to fight back. A pressure wave system was suggested, with high pressure pulses being sent down the gas pipes to turn on, and turn off, all gas lamps fitted with pressure switches. This system wasn’t a success, however, as the pressure pulse

By 1939 the Automatic Telephone & Electric Company Limited was advocating its central management system for street lighting and additional ARP measures such as police, wardens and sirens

administered at the local gasworks had the unnerving side-effect of blowing out all the burners on domestic gas cookers. Therefore, those authorities who still used gas – and it was neckand-neck against electricity in the 1930s – resorted back to either their armies of lamp-lighters or invested in clock controllers. Centralised control for the gas lighting engineer remained just a pipe dream. PHOTOELECTRIC CELL These central management systems enjoyed some limited success for about 20 years, but most authorities continued with time switches or 5th core. The development of the semiconductor in the 1950s and the final realisation of the photoelectric cell as an inexpensive, robust device saw the end of the dream of this form of centralised control. These 1930s solutions may not be as sophisticated as today’s systems, and given the continued popularity of both time switches and photoelectric cells, they may not have been the effective solution promised by their manufacturers. But they can clearly be seen as the direct descendants of today’s far more intricate systems; not in the ways in which they functioned, but in the desire of the lighting engineer to have far more control over his or her lighting system.

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Neither Lighting Journal nor the ILP is responsible for any services supplied or agreements entered into as a result of this listing.

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Public and private sector professional services providing design, technical support, contract and policy development for all applications of exterior lighting and power from architectural to sports, area and highways applications. PFI technical advisor and certifier support, HERS registered personnel.

This directory gives details of suitably qualified, individual members of the Institution of Lighting Professionals (ILP) who offer consultancy services.

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06 October

23-24 November

13 October

29 November

The ILP Lecture, with optician Ian Jordan Venue: Royal Over-Seas League, St James Street, London

North East Region Technical Meeting Venue: Durham County Hall

LuxLive Venue: Excel, London

How to be brilliant… with Jonathan Rush and team Venue: Marshalls Design Space, Clerkenwell, London

13-15 October

IALD Enlighten Americas 2016 Conference Venue: Puerto Vallarta, Mexico

20 October

How to be brilliant…, with Filip Vermeiren, Inverse Lighting Venue: Marshalls Design Space, Clerkenwell, London

20 October

Irish Regional Technical Seminar Venue: Armagh City Hotel

27 October

Autumn Technical Session Venue: Best Western Park Hotel, Falkirk

09 November

Fundamental Lighting Course Venue: ILP, Regent House, Rugby

09-10 November

Highways – Seeing is Believing Exhibition and Conference, the ‘inside-out’ of the highways maintenance and traffic management world Venue: Bruntingthorpe Proving Ground, Lutterworth, Leicestershire

13-15 November

IALD Enlighten Europe Venue: Prague, Czech Republic

06 October – The ILP Lecture, ‘Pain, dizziness and confusion?’. A unique demonstration of the physical effects of light on the body, with optician Ian Jordan, of Jordans Opticians in Ayr, The Royal Over-Seas League, London. This event is free to attend, although booking is essential. Go to:



The challenge of tackling social inequalities in public lighting, including the role lighting can play in improving the quality of life in our cities


16 November

Inside the Lighting Industry Association’s new Lighting Industry Academy, and how leaving the EU could affect skills and qualifications within the industry

17 November

Could lighting columns one day be used as ‘docking stations’ for Amazon drones?

Practical Street Lighting Venue: ILP, Regent House, Rugby

Western Region Charles Endirect Mini Papers. ‘Digging up the past’, with Amanda Reece Venue: Nailsea Rugby Club

For full listings of all regional and national ILP events go to:


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How much more could you be saving? Market-leading reliability and whole life cost savings with Direct DriveÂŽ technology For all your 35W to 250W LED upgrade projects NO driver or photocell replacement costs using Direct Drive Huge reductions in maintenance and risk Lightweight and quick to install weighing just 8kg Full dimming via DALI or pre-set locally, CMS compatible Configurable integrated photocell to eliminate day burning 115,000 hours lumen depreciation at L90B50

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