Light Lines Jan/Feb 17

Volume 10. Issue 1. Jan/Feb 2017

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Northern lights: how the SLL illuminated York

n A Masterclass in the art of lighting galleries and museums 1

Editorial

Secretary Brendan Keely MSLL bkeely@cibse.org SLL Coordinator Juliet Rennie Tel: 020 8675 5211 jrennie@cibse.org Editor Jill Entwistle jillentwistle@yahoo.com Communications committee: Gethyn Williams (chairman) Rob Anderson Iain Carlile MSLL Jill Entwistle Chris Fordham MSLL Wiebke Friedewald Mark Ingram MSLL Stewart Langdown MSLL Linda Salamoun Bruce Weil All contributions are the responsibility of the author, and do not necessarily reflect the views of the society. All contributions are personal, except where attributed to an organisation represented by the author.

Copy date for NL 2 2017 is 23 January Published by The Society of Light and Lighting 222 Balham High Road London SW12 9BS www.sll.org.uk ISSN 1461-524X © 2017 The Society of Light and Lighting The Society of Light and Lighting is part of the Chartered Institution of Building Services Engineers, 222 Balham High Road, London SW12 9BS. Charity registration no 278104

Jill Entwistle jillentwistle@yahoo.com

Current SLL lighting guides SLL Lighting Guide 1: The Industrial Environment (2012) SLL Lighting Guide 2: Hospitals and Health Care Buildings (2008) SLL Lighting Guide 4: Sports (2006) SLL Lighting Guide 5: Lighting for Education (2011) SLL Lighting Guide 6: The Exterior Environment (2016) SLL Lighting Guide 7: Office Lighting (2015) SLL Lighting Guide 8: Lighting for Museums and Galleries (2015) SLL Lighting Guide 9: Lighting for Communal Residential Buildings (2013) SLL Lighting Guide 10: Daylighting – a guide for designers (2014) SLL Lighting Guide 11: Surface Reflectance and Colour (2001) SLL Lighting Guide 12: Emergency Lighting Design Guide (2015) SLL Lighting Guide 13: Places of Worship (2014)

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LATEST SLL Lighting Guide 14: Control of Electric Lighting (2016)

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There is no doubt that the original Night of Heritage Light was a success.

The national TV coverage, the unprecedented general publicity and the awards it garnered throughout 2016 are testimony to the quality and outreach of the event. It also engendered a satisfying esprit de corps among the lighting community, energising and enthusing participants and onlookers alike.

The trick, however, was to build on that success and develop it into something more tangible and permanent. Especially where the public is concerned these events are ephemeral, quickly supplanted in the imagination by one of the myriad distractions of modern life.

NoHL2 has done exactly that.

Pragmatically the decision was made to go for a regional event, this time

focusing activities on the city of York which already has an established annual lighting festival in October (see NoHL2: the next level, p5).

What this venture lacked in scale and national attention, it more than made up for in establishing a deeper connection with the community, particularly the local schoolchildren. Around 80 children, ranging in age from primary level to year 10, were involved in the Pockets of Light aspect of the exercise. They took part in hands-on workshops before submitting their own designs for lighting up some of the city’s heritage landmarks. The winners saw their schemes implemented and viewed by the public over the four nights of the festival.

As Stem ambassadors have repeatedly discovered, children’s response to lighting is invariably enthusiastic. The combination of art and science gives it broad appeal and the magical effects that can be created with light and colour instantly engage a young audience.

According to Dan Lister, who was heavily involved in organising the event, there are at least 30 primary schoolchildren in York who would now like to be lighting designers.

The exercise is clearly a blueprint for the future. ‘We can now begin to reflect on the legacy, a model for a regional NoHL and school engagement programme of Pockets Of Light – ready to be delivered by the next set of willing volunteers,’ says Lister.

Secretary’s column

Happy New Year to you all. Well, if the International Year of Light was a great year, 2016 was just as good.

The Night of Heritage Light received a number of accolades – as well as winning a Lighting Design Award and a darc award, it was given a Highly Commended in the Lux Awards. Well done to all volunteers and partners for delivering an amazing event.

Following on from the success of that event, the society’s volunteers and partners delivered the second Night of Heritage Light (NoHL2) and Pockets of Light in association with the illuminating York festival held towards the end of October (details on p5).

We headed out to Dubai at the very end of October to exhibit at Light Middle East and we welcome the 20 new members who signed up at the event.

We also held the first Ready Steady Light Middle East competition with the organiser Messe Frankfurt. It was very successful and enjoyable with 60 participants split into eight teams.

The winner of the Creative Award for their project, entitled Light-Life, were: Sofia Centofanti, Carlo Ottaviani, Vinod Pillai, Gagan Chibber and Aditi Kumar.

The winners of both the Technical and Peer Awards for their project, Droplets of Heaven, were: Rolf Huüsbeck, Shoeb Undre, Tapiwa Chasi, Chetna Misra, Jonathan Rush, Louise Santiago and Cherine Saroufim. The winners were presented with their trophies at the Awards Dinner which followed the final day of the exhibition. We will be adding a write-up of the event to the news section of the website soon.

We are pleased to welcome our newest Sustaining Member, Secom, to the programme, which has now been running for more than 10 years. We thank all 32 of our Sustaining Members for their continued input.

We had a great time at LuxLive in November and many thanks for all the volunteers who took time out to help with stand duty and all members that came along to say hello. Sofia Tolia was awarded the Young Lighter of the Year title along with the £1000 prize (see News p4). Each of the four finalists received £250 for their efforts and we congratulate all of them.

We are looking forward to the year ahead. President Jeff Shaw will be coaching three young speakers in this year’s PLD-C The Challenge competition. Round 3 will be held from 9-10 February at Brunel University. The winners from this round will go on to present in the finals at the Professional Lighting Design Conference (PLD-C) in November in Paris. More information can be found at the PLD-C website (www.pld-c.com).

‘If the International Year of Light was a great year, 2016 was just as good. The Night of Heritage Light won a number of accolades’ The 2017 Jean Heap Bursary is now open to applicants. This year’s bursary is valued at £4000 and for more details please do contact us (sll@cibse.org).

We will again be hosting Ready Steady Light with Rose Bruford College.

The main event will be on Tuesday 21 March, while the Junior event will take place on Saturday 18 March. Last year team slots sold out very quickly so please do get in touch as soon as possible to secure your place.

We’re pleased to welcome Gethyn Williams as the new chair of the communications committee. The society would like to thank Iain Carlile who is now stepping down from the position to focus on his role as vice president.

We encourage all of our members to think about joining the education and membership committee, which helps guide the society’s education plans as well as membership promotion. If you are interested please do let me know. bkeely@cibse.org

Contents

Editorial

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Secretary’s column

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News

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NoHL: the next level 5 Dan Lister reports on the latest SLL venture, another ambitious event designed to illuminate and educate The art of smart Based on his Masterclass presentation, Roger Sexton looks at the latest source and control technology for lighting art galleries and museums

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Case for an expert eye Paul Ruffles gives an insight into the forensic world of the lighting investigator

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Star light The winner of the 2016 Design a Light competition

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New lamps for old Iain Carlile singles out LR&T papers comparing LEDs with traditional technology

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Cover: NoHL2 – how the SLL brought society members and the schoolchildren of York together for an extraordinary exploration of lighting (see p5) Photography: Lee Wright

Events

For up-to-date information follow us on Twitter @sll100

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NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...NEWS...

Ernest Road to YLOTY success OBITUARY: Wotton (1921-2016)

Lighting engineer Sofia Tolia of Aecom (pictured) has been named Young Lighter of the Year 2016 for her work on energy saving in road lighting.

The winning paper, Variable Lighting Levels for Highways: A Different Approach, was delivered in a 15-minute

presentation alongside three other finalists at the LuxLive exhibition at London’s ExCeL. James Duff won the prize for the best presented paper, A Journey Towards Change. The other finalists were Aisha Robinson, whose paper was entitled A Visible Light Communication Scheme for Use in Accent Lighting, and Eleonora Brembilla, who looked at the Applicability of Climate-based Daylight Modelling.

Tolia’s research for her Master’s diploma thesis centred around the Greek port of Piraeus. Also winning the bestwritten paper award, she examined the current methods used to save energy by dimming road lighting in periods when traffic is predicted to be low, and suggests an alternative methodology.

Richard Caple, SLL vice-president and one of the judges, said that judging was ‘particularly tough due to the exceptional quality of the four finalists’.

Following the success of the International Year of Light and Lightbased Technologies 2015, Unesco is setting up an annual International Day of Light. It will be celebrated on 16 May every year starting in 2018.

The proposal, introduced by sponsors Ghana, Mexico, New Zealand and the Russian Federation, was adopted by the Unesco Executive Board during its 200th Session in Paris held last October (pictured right).

‘The purpose of an International Day of Light will be to provide an annual focal point for the continued appreciation of the central role that light plays in the lives of the citizens of the world in areas of science, culture, education, sustainable development, and in fields as diverse as medicine, communications

On the lighter side...

Kazuhiro Yamanaka’s collapsible moon lamp brings a literal twist to the luminaire. Using a photo-reflecting structure, the user can expand or collapse the light, which can be propped against a wall or laid on the floor. An LED strip is embedded inside the edge of a spring steel frame towards the centre of the circle, creating an even full-moon effect. And should you insist, it can also change colour (www.designboom.com).

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Unesco/A Dunasovs

Day of light dawns

and energy,’ said the official statement.

IYL 2015 featured more than 13,000 activities in 147 countries and involved some 100m participants.

Lighting consultant and academic Ernest Wotton, FSLL, has died in Toronto, Canada, at the age of 95. Also a fellow of the IES and CIBSE, which awarded him the Silver Medal, Wotton also received the SLL’s 2010 President’s Medal, only the second recipient. The following year he received the IES Medal, the institution’s highest award.

Wotton started his lighting career during the Second World War in the lighting division of a UK engineering firm, working on the early adaptation of fluorescent lighting into ships and trains.

He moved to the US after the war and then settled in Toronto. In 1958, he introduced the city to the concept of lighting pedestrian crossings using a demonstration to the city council (complete with rain and smoke effects provided by the fire department), which led to the implementation of pedestrian crossing lighting in the city.

In his 75 years of work in lighting, Ernest made numerous technical contributions to the profession, developing content for and contributing to both institutional and government committees. An early advocate of understanding the effects of light on health and wellbeing, he carried out studies on daylighting. The interrelationship of light, health and energy efficient design were fundamental to his practice, writing and teaching over many years.

‘He was an enthusiast for better quality lighting who advocated his cause with courtesy, knowledge, passion and persistence,’ said Peter Boyce in a tribute to him.

‘He was a very keen educationalist and loved lighting and its history,’ said Lou Bedocs. ‘He was also a charming man and outstanding gentleman.’

Events: Masterclass NoHL 2013/14 York

NoHL: the next level

Lee Wright

How to build on the success of an award-winning event? Dan Lister on the SLL’s latest venture in York that brought local schoolchildren and the society’s members together for an extraordinary exploration of light

NoHL2: the Multangular Tower, part of the original Roman wall and medieval city defences

lapse of concentration and being slow to step back from the line of potential volunteers, resulted in the author being tasked with developing what a ‘region-based NoHL’ might look like and, more important, how it could be delivered.

For the original core NoHL team the aim was to engage the public as much as possible, without becoming responsible for a lighting festival and crowd control. Similarly, as the SLL is always looking at how to connect more with the engineers and designers of the future, Stem engagement with schools was also a strong priority. As a result an NoHL with students as the designers seemed a natural choice, but we didn’t want the kids having all the fun. We were also adamant that members of the society should also have the opportunity to be creative as part of the installation. So we had a vague idea of the What and some experience of the How...but Where? Once again the city where the idea germinated appeared to offer a potential host in the illuminating York festival held in October at half-term. As the place of conception, the beautiful and historic city of York felt like the natural canvas for NoHL2. t

As with many things that are worth doing, although it may not be immediately apparent while in the middle of doing it, ‘it seemed like a good idea at the time’...or ‘never again’ are often muttered in partial jest or justification for making your own life awkward. These were certainly phrases used by both Liz Peck and myself in October 2015, having helped deliver the fantastically well received, but strength-sapping Night of Heritage Light (NoHL) as the SLL’s contribution to the Unesco International Year of Light in 2015.

It wasn’t until sufficient time had passed to cloud the memories, and following an excellent day at the February SLL Masterclass in York, that a number of the delegates and speakers retired to the local hostelry to discuss the day’s topics. With a number of culprits from the previous NoHL in attendance, conversation inevitably bubbled around to the opportunity for a follow-on event to celebrate the anniversary and what form that may take.

The conclusion was that holding a smaller regional succession event to NoHL would be a good thing. A momentary

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NoHL York

Multangular Tower inner surface: part of the original Roman wall and medieval city defences St Leonard’s Hospital undercroft: constructed in the 13th century and part of the former hospital complex and chapel, co-located with the Multangular tower in the gardens of Explore York Exhibition Square: a section of the medieval city wall adjacent to York Art Gallery St Michael le Belfrey – a 16th-century church adjacent to York Minster Each site offered its own opportunities and challenges, typically ranging from finish material, facade relief, viewing positions, availability of power and accessibility to the public.

All of which needed to be understood by the core delivery team, but also communicated to the young ‘designers’.

We were bombarded with imaginative designs and concepts demonstrating a fantastic understanding of the subject matter. A high bar had been set From this seed NoHL2 was born as a one-evening, closeddoor event run for and designed by SLL volunteers from the Yorkshire region (with a little help from some of our North West colleagues). This would allow us, as the SLL, to have a dress rehearsal and springboard into Pockets of Light – a series of four lighting installations delivered over the four nights of the festival, conceived by Yorkshire members of the society, designed by students of York and facilitated by the SLL. The illuminating York organisers provided an education advisor in the form of Colin Jackson from Creative Learning Partnerships (CLP) to help us navigate the challenges of working with young people and getting access to schools.

During the first few weeks of September CLP helped develop our thinking around the format for the student engagement, from which we essentially settled on a two-part approach: a short presentation on career options in lighting followed by a two-hour workshop with a mixture of presentations on light, lighting and lighting techniques. The hands-on workshop with lighting equipment preceded each school being set the design brief and personal/group investigation into the design task. The design brief to the students was simple: to produce a sympathetic lighting design befitting the historic structure.

Colin was also able to quickly identify four institutions that would be keen to embrace the opportunity and negotiated a tailored format for each school to better meet their needs: York College: first and second-year students of the Backstage Arts Diploma as an exercise to develop creative thinking in lighting design Fulford School: careers presentation to 200 year-nine pupils, before a group of 15 female pupils, selected by their science teachers, were given the opportunity to be involved in the workshop and design exercise The Mount: an independent girls’ school that introduced 26 year-10 girls as part of the science and art curriculum St Wilfrid’s RC Primary School: year-six primary school pupils taking full advantage of the combined curriculum opportunities lighting provides, mixing science and art within one topic

Liz Peck

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The match was made in heaven. The illuminating York organisers welcomed the society with open arms and were keen to engage and support the project in any way they could.

Our focus on the architecture and heritage of the city fitted perfectly with their mission statement of ‘Discovering York in a new light’ with the curators wanting to deliver unique art commissions that were a part of the fabric of York.

The festival also had a long struggle with gaining greater engagement with the younger members of the community and incorporating more educational elements, so our aspirations of engaging local schools also met this challenge perfectly.

Members of the NoHL core team met with the festival curators to flesh out the details of how the SLL could be involved, taking on one of the artist roles. Walking the York Snickelways and paths least trodden the team looked for inspirational architecture that was close to other sites in the festival, not normally lit, often overlooked, and which would form a suitable subject for our young designers. Four sites were eventually identified:

Pockets of Light: Exhibition Square 2, a section of medieval city wall, by St Wilfred’s Primary School

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Week beginning 26 September saw SLL volunteers visit the schools and college. Working in pairs, with myself, Liz Peck, Helen Marsh, David Battersby, Gethyn Williams and Graham Parker forming the core team, we delivered the presentations and interactive workshops. Supported by Colin, these were fun and engaging exercises with students getting hands on with the workshop kit, experimenting and investigating the possibilities of light. The students were engaged, asking intelligent questions and made the presenters think on their feet.

Liz Peck

NoHL York

Pockets of Light: Multangular Tower lit by Fulford School

The day saw a collection of SLL members travel to site not only to prepare for the coming week, but also for their opportunity to work as a team across the two sites to deliver NoHL2. Hidden from the public the creative skills of the SLL members were on show (along with the now obligatory ‘blue cubes’), captured for prosperity by Lee Wright. t

Following the workshop, students were encouraged to develop the design as part of their curriculum, before submitting it to the team for judging. The rules for the submission were easy: provide a picture of the lighting design (rendering), a plan indicating where they thought luminaires would be required and finally a written description of the concept behind the lighting design (though for St Wilfrid’s Primary school this was adapted to a poem about light).

Unfortunately (or fortunately) the standard was extremely high as we were bombarded with imaginative designs and engaging concepts demonstrating a fantastic understanding of the subject matter. A high bar had been set and the NoHL team judged the designs based on the creative visual content of the submission, strength of the concept behind the design and the practicalities of delivering the solution at the festival.

All that remained was to source the equipment, raid the Ready Steady Light stores, call favours in to borrow equipment, source cabling, organise power sources, liaise with building owners, health and safety requirements, design interpretation boards and all the other logistical requirements of running four concurrent sites within the centre of a city at once. All of which was organised and delivered in under two weeks. As ever the manufacturing and supply chain fraternity stepped up to the mark, going above and beyond what any reasonable request would allow – with all the equipment arriving on site, like clockwork, on 24 October 2016.

Light Years Away!

When the Romans built our city walls, Spacemen were light years away.

When Harold fought the Vikings for York, Moon landings were light years away.

When the Tudors set our churches ablaze, The Sun became the king of space.

Then when Victoria rules the land, In our system, Neptune found a place.

Now at night our city glows bright and proud, With our history on show by the day.

So we colour our future here and now, For learning light years away.

– Izzy Hanson, year-six pupil at St Wilfrid’s RC Primary School

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Lee Wright

NoHL York

NoHL2: Multangular Tower

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The subsequent days, 25-29 October, saw SLL volunteers deliver and man the sites as part of Pockets Of Light at the illuminating York festival. One of the winning ‘designers’ Alexandra Cornell Atkinson, a second-year student from York College, joined us for a day to programme the complex colour-mixing sequences within St Leonards undercroft.

A timely piece of work experience before her interview at university the following day.

All the students who took part in Pockets of Light have earned themselves an Arts Award, a qualification suite coordinated by Arts Council England. Facilitated by Creative Learning Partnerships, we have been able to assist the students in achieving an Arts Award Discover which is achieved by participants taking part in arts activities (in this case lighting design), finding out about the work of artists and their career paths (the activities of the SLL and the careers of the presenters) and recording what they learnt and enjoyed (via feedback forms and discussions at the end of the workshops).

All participants will receive a certificate from Arts Council England/Trinity College London.

Reading my report, you may perhaps be taken by how much is mentioned about the build-up, but very little about the festival itself. But without belittling the amazing work of the volunteers on site, for the core team that was the point. This story, NoHL2 and Pockets of Light, is not about the physical outcome, but about the journey taken by the 78 students who took part in our workshops and had their first real exposure to lighting design as a possible career. To a certain extent the lighting delivered at the festival is immaterial and not as important as the subtly lit interpretation boards, however the feedback from visiting teachers, students and their parents

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presented to and overheard by the volunteers during the festival has been genuinely heartwarming.

Without the volunteers it simply would not have been possible to deliver Pockets of Light. Not only in the preparation of the equipment, but also the dogged support in installing and stripping out the four installations each evening in order to protect the loaned equipment. No mean task considering the 100 luminaires, five gobo projectors, two haze machines and DMX control and mixing desks the students’ designs needed.

As we come to a close to NoHL 2015 (one Lighting Design Award, one Darc Award and one Highly Commended at the Lux Awards), we can now begin to reflect on the legacy, a model for a regional NoHL and school engagement programme of Pockets Of Light – ready to be delivered by the next set of willing volunteers.

‘The question, “Who wants to be a lighting designer when they grow up…?” was met with 30 small hands bolting upright into the air. The real legacy of Pockets of Light.

A big thanks to the core team of Dan Lister, Liz Peck, Helen Marsh, David Battersby, Gethyn Williams and Graham Parker. Thanks also to acdc lighting, Amerlux, Apollo Lighting, BlackLight, Erco, Lumenpulse, Martin, Rosco, Rose Buford College and Tryka LED, and to the SLL and CIBSE members of the Yorkshire and North West Regions: Paul Ingham, Alastair Sherry, Nick Howard, Georgina Penfold, Steve Redhead, Charlie Comerford, Brian Healy, Shahin Darvishnarenjbon, Eliot Horsman, and Sabrina Mostofa. And thanks to Brendan Keely and Juliet Rennie for the stalwart support from Balham HQ.

SLL Masterclass 2016-17

The art of smart Light quality is the essential starting point. It impacts visitor perception of the gallery’s architecture itself, the artwork on display, and the visitors’ sense of themselves in the space.

Sustained colour point consistency and the best possible colour rendering of course are relevant, but so are non-visible SPDrelated (spectral power distribution) attributes that could cause pigments in paints and fabrics to fade or change in hue.

Light quality is a function of the LEDs and phosphors used in the light source. But the quality of dimming is also important, in terms of its smoothness, its depth and its lack of flicker, including non-visible flicker where links to negative physiological effects have been claimed. In gallery applications colour-point stability through the dimming cycle is also important.

Fig 1: peer-to-peer networked communication including lighting offers many advantages in a gallery

One way of ensuring good quality dimming is to have the LED driver and dimming circuitry incorporated into a Smart LED Module. Perfect tuning of modulation and frequency is then ensured. These modules can incorporate diagnostic sensors that detect temperature, power status and more, allowing a microprocessor to report real-time module status, as well as protect the module from itself. For example, the thermistors at temperature-sensitive components in the module can trigger dimming if the module begins to overheat because of a site-related issue.

This leads to the main topic of this article: an addition to the electronics that enables wireless communication. Figure 1 sets out a vision of peer-to-peer communication. This involves forming a seamless network of intelligent, interoperable devices. Intelligence allows these Smart LED Modules to make independent decisions based on direct, real-time input from

sensors and switches, without the delays and inconsistencies associated with centralised controllers. This decentralised intelligence offers many benefits in a gallery.

The use of simple, intuitive apps demystifies controls, allowing anyone to carry out commissioning and operation.

Commissioning can be as easy as selecting a given track spot on a handheld phone or tablet and setting the level with a virtual slider. Groups and presets can be created by ‘dragging and dropping’. And when the exhibition is changed the process is simply repeated – no wires or controllers to worry about. Move the luminaires, and the rest is all software. There are no driver boxes and all the action is below, not in or above, the ceiling.

Figures 2 and 3 show smart lighting being trialled and commissioned respectively at the Van Gogh Museum, Amsterdam, and the Museon, a museum of culture and science in The Hague. The wireless localised control discussed here can even be ‘overlaid’ with a wired backhaul system used for scheduled on/off times, energy monitoring of all building services, alerts on maintenance issues and so on.

Smart LED Modules can save initial cost on drivers, dedicated control wiring and hubs. But they can also provide significant savings on maintenance costs. Module selfmonitoring and auto-correction can prolong module life, and real-time reporting of operational information makes preventative maintenance possible.

Maintenance is especially important if downtime is costly or high ceilings necessitate scissor lifts. Think of the high, vaulted Victorian ceilings in some UK museums, or where closely spaced exhibits are threatened by a cherry picker’s turning radius. With continuous, accurate diagnostics information (Figure 4), maintenance becomes more efficient and cheaper.

Maintenance people have to go on site once only, knowing in advance what the problem is. And they bring the right parts with

Fig 2: simplified flux setting using wireless smart controls in a trial at the Van Gogh Museum, Amsterdam

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Based on his presentation for the latest Masterclass: Lighting Knowledge series, Roger Sexton of Xicato looks at how smart sources and wireless communication can transform the gallery environment

SLL Masterclass 2016-17

Light levels can be raised slowly as the visitor reaches a statue to create a revelation. This is not simply aiding the journey – lighting becomes part of the show

Fig 3: simplified grouping using wireless smart controls at the Museon, The Hague

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them. Alerts could be sent to a tablet for small installations, or for larger installations, via a gateway linked to bigger Content Management Systems with dashboards in FM control rooms.

Smart LED Modules can also report historical data on operating hours, temperature and lighting intensity levels (see also Figure 4), enabling status reports and recommendations for group replacement cycles. This also allows manufacturers to offer extended warranties based on actual usage data.

Some museum owners hire consultancies to provide Building Information Management (BIM) services. Smart LED Modules can contribute by providing accurate real-time and historical input data on which BIMs depend to identify issues and finetune building management policy for maximum efficiency.

They can also be central to energy saving. Lux sensors linked wirelessly to Smart LED Modules can detect incoming daylight and trigger a decrease or increase in the artificial lighting. The modules can be programmed to prevent irritating changes based on transient conditions. While daylight compensation has been available for decades, wireless sensing and independent control makes it more flexible and more powerful. Exactly the same can be said for motion sensors.

Programmable occupancy and lighting states, with configurable delays and ramp times, can provide truly efficient, adaptive control to individual visitors, while preventing abrupt changes that could mar a visitor’s experience. A lone user in a gallery may not even notice that as he or she approaches a given painting the lighting has slowly been increasing in their direction of travel. Visitors can start off in a cocoon of light that gradually expands. Reach point A then lighting at a point B comes on as guidance. Light levels can be raised incrementally as the visitor reaches a statue to create a revelation.This is not simply aiding the journey – lighting becomes part of the show.

Sensor-controlled lighting can of course be a major aid to

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Fig 4: with continuous and historical operational data maintenance becomes more efficient and cheaper

conservation. In galleries there is a balancing act between access and conservation. For conservators, light is a menace – all light degrades paintings over time. In planning an exhibit, the conservator calculates a maximum allowable light dose.

This takes into account the artwork’s sensitivity, the light source SPD, and therefore damage factor, and the work’s preservation target – the time before a ‘just noticeable difference’ is evident.

Sensors can measure lux hour exposure on a painting, providing data that is digested by specialised software into practical advice, warnings, alarms and so on.

Just as wireless sensors can stream sensor data, mobile devices can transmit control commands, and Smart LED Modules can stream operating data for maintenance purposes.

The same modules can emit periodic Eddystone or iBeacons that allow a mobile app to identify the visitor’s location in the museum for a variety of purposes.

SLL Masterclass 2016-17

Fig 5: indoor location services – a mobile app compares the received signal strengths from different beacons

The signal from global positioning systems (GPS), which enables car navigation and speeding delivery of emergency services, does not enter buildings, and even if it did it would not be accurate enough for an interior. For indoor use, for example, knowing which floor of a building someone is on rather than just a point on a map is important. Museum visitors would like to know which picture they are close to with an accuracy of well under 1m, so that they can be provided with information about it.

There is a lot of activity in the industry to provide these indoor location services using Bluetooth Beacons. Beacons

Fig 6: indoor location service demonstration at the Van Gogh Gallery, Amsterdam

advertise proximity-specific data up to 100 times a second, for another Bluetooth device to pick up. A mobile app compares the received signal strengths from different beacons (Figures 5 and 6), locating the user and calling up information suitable to that location, whether it is details of a particular exhibit or indoor mapping. This information can supplement that on wall plaques, for example, as well as provide up-to-the-minute links to events, dates or other temporary exhibits. Wayfinding can guide users on a preconfigured tour or to related exhibits, suggest an appropriate route to the nearest bathroom or point them to the museum cafe or shop.

Until now beacons have been stand-alone, plastic, batterypowered devices that trade off transmission frequency and power against the maintenance hassle of battery replacement.

Smart LED Modules allow optimum beacon configuration for more accurate location, while eliminating battery maintenance.

During each Masterclass session all of the above ways of using the technology are demonstrated. The session does not cover a detailed comparison of the different wireless protocols available, but the demonstrations use Bluetooth Low Energy enabled Smart LED Modules, sensors and switches with a reference control panel and app developed by Xicato.

Bluetooth Low Energy has advantages in terms of speed, low data packet size, low energy, easy embodiment, uptake in all smartphones and tablets, being the technology underlying iBeacon and the Physical Web, and the standards are open and licence free. A Standard Bluetooth Mesh code will become available next year with interoperability aims in mind. @sll100

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Professional insight

Case for an expert eye In the first of a two-part article, Paul Ruffles looks at the work of the lighting investigator: where Sherlock Holmes meets CSI

I’ve been carrying out technical investigations and providing expert witness advice for many years and have found that it has informed my own knowledge and practice of lighting enormously. So I thought I should try to share some of this with a wider audience as well as giving you some insight into the way these forensic investigations usually go.

The first point to establish is the difference between a technical investigation and expert witness work. A pure technical investigation is where a client has lighting equipment that may have been installed for some time and there is no expectation of finding anyone responsible for any failures; it just isn’t working properly now. They may well have had electricians in to prod the lights and check the wiring, but often the suggestion is to ‘just replace the lot’. This can obviously be a very expensive option; it is often cheaper to have a thorough objective investigation that may well reveal some problematic component, setting or interaction that others have missed.

Some technical investigations are on new builds where something is not right; the consultants, contractors and manufacturers concerned cannot pin it down, but are all willing to sort it out once the problem has been identified. An objective and fresh set of eyes can work simply and thoroughly through the lighting system without presumptions or any self-interest.

Expert witness work is where there is a dispute between parties and an objective investigation and report is needed to establish reasons for the failure(s) and sometimes to apportion blame. The dispute could also be about patent or design infringement, which still needs an investigation of a different sort and an opinion on whether an infringement has taken place in whole or part. You also need to realise that during pre-trial negotiations or in court a barrister may ask a question about an obscure technical issue deliberately to unbalance an opponent or to muddy the waters. So it is important to try to think of any question that may be used in this way and to have the answer provided in your report, even if you think it minor or irrelevant.

The two-year winge point I am often called in by a client some two years after handover of a new building. This is not really surprising as the first year following handover is normally the defects liability period, where problems and snags are meant to be sorted out. Most reliable contractors, consultants and manufacturers try their best during this period to do this. However, if the problem is complex or uncertain they may not be able to solve it during the defects period. As the months roll by the companies involved tend to become less interested in solving the problem – they have gone

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on to new projects and personnel involved may well have left.

In any case, they may all be certain that it is not their fault and so why does the client keep bothering them? By the time the second year is getting on the client loses patience and calls in an independent expert to look at the problem, decide what has gone wrong and, often, who is to blame.

Again the independent expert has the advantage of being completely new to the project and can view everything with an unbiased eye. For this reason, it is important to take the client’s view on who is to blame as just one more opinion – the expert needs to draw his or her own conclusions, based on the facts and details of the investigation. Indeed, on one project I found my building owner client to be partially responsible for the problem, as at one point he had agreed to a specification change.

Is 485 lux good enough?

Oh yes, I’ve encountered this vexed issue. ‘The spec says 500 lux, but I’ve found a corner where it is 485 lux.’ My first action on getting an enquiry of this nature from a client or tenant of a building is to run through the real differences between 485 lux and the specified 500 lux – usually so little different that their employees will not really be disadvantaged. Some are content with this, but others want their ‘pound of flesh’ – sometimes as a way of getting back at a consultant or contractor that they feel may not have performed well in other respects. Once more, you cannot be drawn into any background reason for the action taken; you just have to go in with a clear and objective mind.

On one case with a tenant in a city office building, they complained to the landlord that they were not getting the 500 lux specified in the lease and demanded action. The building’s design consultants said they had gone back in with a light meter and it was fine. The landlord needed an independent expert to decide who was right. Of course the reasons the two parties were getting different results was that they were using different light meters with unknown calibration dates and were measuring the level in different ways, at different times and in different parts of the room.

My first step was to establish with the consultants that they would carry out a formal test one dark evening with a freshly calibrated meter on a properly set-out measurement grid across an empty office space at the correct working plane

Professional insight

level. We all met on site late one evening and we established that the lights had been on for at least two hours and that the room temperature was normal for the office. The consultant set about the measurements on the pre-set grid of points they had carefully laid out across the carpet that afternoon. I took a few sample readings with my own freshly calibrated meter to check all was well. After the calculations of average measured light level had been made, the figures needed to be adjusted for the differences in the various factors that go to make up the maintenance factor. The factors are different for the actual time of use of the installation compared to those used by the consultants in their calculations of maintained illuminance – the slight differences in room surface reflectance from design assumptions to those used in the calculation also had to be taken into account. After all that had been done, the results were looked at and all parties agreed with my adjudication that the light levels were not at the specified level. So, did the tenant get new lighting? No. In fact they just wanted to use the result as a lever over the landlord to get new carpets.

Cases like these have also allowed me to discuss the technical or procedural issues raised by the cases with the other members of the SLL technical committee – with case confidentiality maintained of course. These discussions over the years have included how we define uniformity and diversity, how we measure illuminance levels, surface temperature of luminaire parts and, just this year, how we calculate and measure lighting levels on staircases. This last case discussion led to the writing of the brand new guide on staircase lighting, which will be published soon.

Together they fail Problems arising from interactions between components have made up some of my most complicated investigation work over the years and rarely fail to throw up new and exciting ways that things can go wrong. Often the independent expert is called in on these cases because everyone else involved has either ground to a halt trying to solve the problem or is refusing to cooperate or admit any of their components could possibly be at fault. I will give two examples of just how difficult it can be for those involved to spot the problem.

Some years ago one London bank headquarters was experiencing random groups of lights switching on and off – except, of course, when anyone came to find the problem, when they all worked perfectly. Initially the controls suppliers came in and tested their system and found no problems.

Next the luminaire supplier came in and looked at their luminaires and found no problems. The lamp manufacturer similarly found their lamps to be fine. But still sometimes some groups of lights would turn on or off. In frustration the owners of the block called me in to do a forensic examination of the system and find out what was going on.

As a new set of eyes, my initial action was to get familiar with the technical characteristics of the lighting and controls and then to stand back to see how the system was used in the building. The users were supplied with handheld infrared controllers that linked via ceiling-mounted receivers to the lights near their desks. The system could be centrally configured to allow any given controller to switch or dim any group of the lights. Feedback from various users made it clear that the random switching happened sometime after they arrived at the office and nearly always in areas where they were working – there never seemed to be problems in areas where no one was working. This led to a hunch which, with some simple testing, identified the problem.

In the morning when the employees arrived the desks were

fairly clear but as the day progressed some of the desks got covered in nice white paper. This paper then reflected more of the light from the high-frequency fluorescent fittings back up to the ceiling. It was the infrared component of the light that was swamping the IR receivers of the control system causing them to turn lights on or off erratically. This highlights one of the advantages of an outside view on a problem – each supplier had looked at their own little part of the system and not considered the overall picture and subsequently wasted time and money testing their components which, on their own, worked just as expected.

A similar sort of problem occurred in a London company HQ where new lamps in uplights had been failing throughout the building. The initial response was to blame the medium wattage discharge lamps and indeed the reputable lamp manufacturer supplied a large batch of new lamps. When these started failing a few months later they tested them and concluded they had been overdriven and suggested the ballast was to blame. The reputable ballast manufacturer supplied some new ballasts that were retrofitted into the uplights. The ballast manufacturer tested the removed ballasts and said they may have been overstressed and suggested that the ballast, and therefore the lamps, had been switched on and off too often by the control system. So the control supplier came in and did tests and concluded that their system was fine and the switching was infrequent and should not have unduly affected the lamp life – the lamp manufacturer agreed with this conclusion. So everything was perfect, but still lamps kept failing.

When I came in my first problem was to find one uplight that hadn’t been fiddled with by someone and so still had the original lamp, ballast and control module in as supplied by the uplight manufacturer. Once this was obtained, laboratory tests could be carried out and conclusions drawn. In fact, it

turned out that the uplight manufacturer was at fault – the one party not so far considered a potential culprit. The combination of a lamp, ballast and control module in the compact uplight produced too much heat. The control module had been fitted as a special and this had added a small amount of extra heat but also took up volume inside the uplight so reducing air circulation. The result was that both the ballast and control module were stressed and the lamp overrun.

In the second part of his article in the March/April issue, Paul Ruffles will look at patent and design infringement, problems with exterior lighting and what makes you qualified to be a lighting investigator. @sll100

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Competition

Star light

A friendly but elegant design wins the Sparks prize Story Star by IA Interior Architects was the winner of the inaugural Design a Light competition 2016. The judges, who included SLL secretary Brendan Keely, chose it ‘for its mix of interactivity, simplicity, friendly and elegant design, while reflecting the Sparks brand and ethos’.

Runner-up was Cundall with the Cell, while Chantal and Molly Staats took third place with Molly the Rainbow.

Design a Light marked the 25th anniversaries of children’s medical research charity Sparks and lighting manufacturer Future Designs, the competition’s sponsor. Together they aimed to raise funds and awareness for the charity.

The results were announced at the Sparks annual Winter

‘The time, thought and effort that has gone into this from the entrants and judges has been inspirational’ Ball in the Roundhouse, north London, on 30 November. The top three designs were manufactured by Future Designs and auctioned at the event.

The successful bid for Story Star came from Paul Flatt, chair and CEO of Hurley Palmer Flatt, raising £6500. The total raised for Sparks through the competition came to more than £15,000.

‘The Design a Light competition called on the leaders in the lighting, design and property communities to create a unique light that represents the Sparks brand, and the results have been stunning,’ said David Clements, managing director of Future Designs. ‘The time, thought and effort that has gone into this from the entrants and judges has been inspirational.’

Winning ingredients: the base of the Story Star by IA Interior Architects forms a glowing star, acting as a night light. A clear Perspex disc can be drawn or written on and, when inserted, projects the message or image on to the ceiling

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LR&T essentials

New lamps for old

Iain Carlile looks at three recently published papers which compare traditional and new technology, and the evaluation of discomfort glare Examining some of the issues surrounding the retrofit of interior lighting to LED technology, Gentile et al conducted a field study comparing fluorescent and LED installations in a classroom environment. For the study, four identical classrooms were used in a secondary school in Sweden, with pupils aged 17-18 years of age. As a control, two of the classrooms were set up with a direct/indirect T5 fluorescent scheme, while the two experimental classrooms were set up with an experimental indirect LED lighting system. The students undertook their normal educational activities in these environments for an entire academic year. During the field study the light environment, electricity consumption, and students’ mood, light perception and saliva cortisol concentration were monitored.

From the field study only marginal differences were found between the two different classroom types, with a slight preference towards the experimental LED installation. Only small energy savings were achieved in the experimental LED classrooms due to high parasitic losses.

Also considering fluorescent and LED light sources, Wang et al present a paper considering visual fatigue in users of visual display terminals (VDT). All test subjects completed eight hours of VDT work under both light sources. Visual fatigue was investigated through subjective reports of symptoms, ophthalmological parameters and physiological signals. They found that visual fatigue increases with prolonged use of VDTs and, compared to fluorescent light sources, that the LED luminaires resulted in greater near-point accommodation, blink amplification and oxygen saturation, but less dry eye symptoms, less best-corrected distance, visual acuityand less high-frequency electrocardiogram power. The authors noted, however, that while these effects were recorded, the symptom of ‘tired eyes’ was reported as moderate, and all other symptoms as slight.

Safdar et al consider problems with the Unified Glare Rating (UGR) method for the evaluation of discomfort glare, specifically the non-uniform luminance of the glare source.

(a) The relative spectral power distribution of LED and fluorescent luminaires and (b and c) change in normalised intensity over time for fluorescent and LED luminaires respectively (Y Wang et al)

They propose a new image-based metric, called the Neural Response-based Glare Model (NRGM), as a way to evaluate discomfort glare by modelling the human neural response.

The proposed image-based system evaluates both the luminance spatial distribution and the background luminance.

Experiments using non-uniform LED sources were carried out, comparing the results of the proposed image-based method against the UGR. They found that the NRGM gave a similar performance to UGR for luminaires which had symmetric patterns of LEDs, however they outperformed the UGR method for asymmetric patterns of LEDs. Iain Carlile, MSLL, is an associate of DPA Lighting Lighting Research and Technology: OnlineFirst In advance of being published in the print version of Lighting Research and Technology (LR&T), all papers accepted for publishing are available online.

SLL members can gain access to these papers via the SLL website (www.sll.org.uk) A field study of fluorescent and LED classroom lighting N Gentile, T Goven, and T Laike Visual fatigue following long-term visual display terminal work under different light sources Y Wang, X Zhong, Y Zhang, Y Tu, L Wang, Y Chen, C Zhang and W Zhou A neural response-based model to predict discomfort glare from luminance image M Safdar, M Ronnier Luo, M Farhan Mughal, S Kuai, Y Yang, L Fu and X Zhu

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EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS

2017 11 January West Midlands Region CPD Technical Seminar on TM30 Speaker: Peter Raynham Venue: Birmingham Chamber of Commerce www.sll.org.uk 26 January Masterclass: Lighting Knowledge Series Human Responses to Light Venue: Library of Birmingham Centenary Square, Birmingham www.sll.org.uk 7 February CIBSE Building Performance Awards Venue: Grosvenor House Hotel, London www.cibse.org/buildingperformance-awards

7-9 February: Light School at the Surface Design Show

7-9 February Light School at the Surface Design Show (Supported by the ILP) Venue: Business Design Centre, London www.surfacedesignshow.com/light-school

27 April How to be Brilliant (Organised by the ILP) Venue: Marshalls Design Space London EC1 jess@theilp.org.uk

9-10 February PLD-C The Challenge Warm-up (Round III and mini-conference) Venue: Brunel University, London http://pld-c.com/warm-up-in-londonuk/

4 May Lighting Design Awards Venue: London Hilton Park Lane http://awards.lighting.co.uk

23 February Masterclass: Lighting Knowledge Series Human Responses to Light Venue: The Lowry, Manchester www.sll.org.uk

9-11 May Lightfair International Trade Show and Conference Venue: Pennsylvania Convention Center www.lightfair.com

18 March Junior Ready Steady Light Venue: Rose Bruford College Sidcup, Kent www.sll.org.uk

18 May Masterclass: Lighting Knowledge Series Human Responses to Light Venue: London www.sll.org.uk

21 March Ready Steady Light Venue: Rose Bruford College Sidcup, Kent www.sll.org.uk

25 May SLL AGM and Awards Venue: TBC www.sll.org.uk

30 March Masterclass: Lighting Knowledge Series Human Responses to Light Venue: M-Shed, Bristol www.sll.org.uk

25 May How to be Brilliant (Organised by the ILP) Venue: Marshalls Design Space London EC1 jess@theilp.org.uk

4-9 April Euroluce Venue: Fiera Milano, Milan www.salonemilano.it

14-15 June Professional Lighting Summit (Organised by the ILP) Venue: Crowne Plaza, Glasgow jess@theilp.org.uk

27 April Masterclass: Lighting Knowledge Series Human Responses to Light Venue: The Lighthouse, Glasgow www.sll.org.uk

1-4 November Professional Lighting Design Convention Venue: Palais des Congrès de Paris http://pld-c.com

Lighting Masterclasses: Masterclass: The Lighting Knowledge Series is kindly sponsored by Holophane, Thorn, Trilux and Xicato. For venues and booking details: www.sll.org.uk

LET Diploma: advanced qualification by distance learning. Details from www.lightingeducationtrust.org or email LET@cibse.org CIBSE Training: various courses across the whole spectrum of lighting and at sites across the UK. Full details at www.cibse. org/training-events/cibse-cpd-training LIA courses: details from Sarah Lavell, 01952 290905, or email training@thelia.org.uk For up-to-date information follow us on Twitter @sll100