Light Lines January/ February 23

SECRETARY

Brendan Keely FSLL bkeely@cibse.org

SLL COORDINATOR

Cara Littlechild clittlechild@cibse.org

EDITOR

Jill Entwistle jillentwistle@yahoo.com

COMMUNICATIONS

COMMITTEE:

Eliot Horsman MSLL (chair)

James Buck Iain Carlile FSLL

Jill Entwistle

Chris Fordham MSLL

Rebecca Hodge

Stewart Langdown FSLL Luke Locke-Wheaton

Rory Marples MSLL

Linda Salamoun MSLL

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 LL2 2023 IS 6 JANUARY

PUBLISHED BY

The Society of Light and Lighting

222 Balham High Road London SW12 9BS www.sll.org.uk ISSN 2632-2838

© 2023 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

Unit C, Northfield Point, Cunliffe Drive, Kettering, Northants NN16 9QJ Tel: 01536 527297

FROM THE EDITOR

The end of 2022 saw the publication of the new SLL Code for Lighting (see p8). It is a beast of a reference work, summarising the latest standards in all aspects of the lit environment. Not only that, but it makes sense of them, offering commentary and advice. It also drills down into all the basic principles of lighting, calculation and metrics.

Around the same time as the Code was launched, a special issue of Lighting Research and Technology was published, entirely devoted to the proposals of one individual, Kit Cuttle, an unprecedented event (see p11). His LiDOs Procedure advocates a shift away from task to ambient lighting.

It is an interesting juxtaposition in that Cuttle gently challenges the thinking behind existing lighting standards for interior spaces.

But the point is that both the Code and Cuttle are actually in agreement in wanting to encourage good, creative, innovative lighting that promotes pleasant, stimulating spaces,

human wellbeing and energy efficiency.

Over the years the Code has embraced new thinking, endorsing the move away from the horizontal plane as a baseline metric, encouraging designers and specifiers to think creatively rather than solely in terms of calculation.

'The role of the lighting standard should be to eliminate bad options – just that and nothing more,' says Cuttle. Peter Raynham, the theneditor, said much the same thing when the last edition of the Code was published in 2012: 'When we think of what the role of the Code is, it’s actually to stop bad lighting.'

JILL ENTWISTLE JILLENTWISTLE @YAHOO.COM

CURRENT SLL LIGHTING GUIDES

SLL Lighting Guide 0: Introduction to Light and Lighting (2017)

SLL Lighting Guide 1: The Industrial Environment (2018)

SLL Lighting Guide 2: Lighting for Healthcare Premises (2019)

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 (2021)

SLL Lighting Guide 9: Lighting for Communal Residential Buildings (2022)

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 (2022)

SLL Lighting Guide 13: Places of Worship (2018)

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

SLL Lighting Guide 15: Transport Buildings (2017)

SLL Lighting Guide 16: Lighting for Stairs (2017)

SLL Lighting Guide 17: Lighting for Retail Premises (2018)

SLL Lighting Guide 18: Lighting for Licensed Premises (2018)

SLL Lighting Guide 19: Lighting for Extreme Conditions (2019)

SLL Lighting Guide 20: Lighting and Facilities Management (2020)

SLL Lighting Guide 21: Protecting the Night-time Environment (2021)

SLL Lighting Guide 22: Lighting for Control Rooms (2022)

Guide to Limiting Obtrusive Light (2012)

Code for Lighting (2022)

Commissioning Code L (2018)

SLL Lighting Handbook (2018)

Printed in UK

E: gary@matrixprint.com

CIBSE TM66: Creating a Circular Economy in the Lighting Industry (2021)

FROM THE SECRETARY

We are delighted to confirm that the SLL Code for Lighting 2022 was released at the end of November (see p8) and members can download the publication from the CIBSE Knowledge Portal (see box right). The hard copy is also available to purchase. We thank Sophie Parry (head of UK Akademie, Trilux Lighting), who was the Code for Lighting project manager and editor-in-chief.

Chapter authors and principal contributors included Sophie along with: Allan Howard (group technical director, lighting, WSP), Professor Peter Raynham (at the UCL Institute for Environmental Design and Engineering), Peter Thorns (Zumtobel Group Lighting) and Ruth Kelly-Waskett (Hoare Lea).

We thank all the contributors, reviewers, the SLL technical and publications committee, and all involved in this project. It is a considerable piece of work and we hope you all find the publication of great use.

We welcome Eco Fix UK Energy Solutions to the SLL Sustaining Membership programme. If you want more details on the programme please do drop me a line. A list of all SLL Sustaining Members along with the benefits of membership can be found on the SLL website (again, see box).

Back in May 2022 we hosted the Responsible Outdoor Lighting at Night (ROLAN) conference with our partner Dr Karolina ZielinskaDabkowska. We are pleased to confirm that the conference recordings are now available to purchase at a small fee on demand. All 44 videos, including the introductions, presentations and panel sessions, are now available from the ROLAN website (box).

The SLL has signed the Responsible Outdoor Lighting at Night Manifesto for Lighting Professionals (see p4) along with the ROLAN conference Founding Partners: the International Association of Lighting Designers (IALD), International Dark-Sky Association (IDA), Illuminating Engineering Society (IES), ILLUME, Institution of Lighting Professionals (ILP) and the Lighting Industry Association (LIA).

The UN Sustainable Development Goals do not explicitly refer to external illumination and its multiple impacts. The Founding Partners of the ROLAN movement are keen to address this in support of the SDG Goals. The manifesto sets out 10 core principles for external illumination and a plan of action to implement positive change in the lighting community, to lead to a more sustainable, healthier and safer future for all. For

• To download/purchase the new Code for Lighting: www.cibse.org/knowledgeresearch/knowledge-portal/ sll-code-for-lighting

• For more details about SLL Sustaining Membership: www.sll-membership/ sustaining-membership

• To watch the ROLAN conference: https://go.cibse.org/ROLAN22

• For more details of the ROLAN Manifesto: www.cibse.org/society-of-lightand-lighting

• For more details of the Jean Heap Bursary: sll@cibse.org

the manifesto details take a look at the Latest News section of the website (box).

Congratulations to the four finalists who took part in the SLL Young Lighter 2022 in midDecember. We will feature the winning paper in the March/April issue of Light Lines.

Thanks to all those who took part in SLL Ready Steady Light in association with Rose Bruford College back in October 2022 (see p6). Well done to Team Cundall on winning the technical award, Team CBG Consultants for winning the artistic award and Team MID for winning the peer prize. A special thanks goes to the judges for the event: Andrew Bissell and Eliot Horsman from SLL, Christopher Knowlton and Emma Cogswell from IALD, and Ben Ratcliffe from Rose Bruford College. The lead student for the event was Daniel Paget – well done Daniel.

The 2023 Jean Heap Bursary has now been launched. There is up to £4000 of funding available which is paid in four instalments. Each year, a panel of expert judges look for a specific piece of lighting research that could benefit SLL members and the industry as a whole. Please email us for further information (box).

BRENDAN KEELY

BKEELY @CIBSE.ORG

EDITORIAL SECRETARY'S COLUMN NEWS

MIND THE GAP

How can designers and manufacturers get the high-quality, evidence-based research they need? Francis Pearce on a recent SLL debate that provided insights from industry and academia

NATURAL SELECTION

The winners of the latest Ready Steady Light competition found their creative inspiration in nature

THE BOOK OF LIGHT

The new SLL Code for Lighting has just been released. Sophie Parry outlines the updates which appear in the final version –and looks at the history of the Code

MEASURE OF PROGRESS

For the first time in its history LR&T has devoted an issue to one theme: Kit Cuttle and his proposal for a new approach to lighting design. He summarises the thinking behind his LiDOs Procedure

REFLECTION AND PERCEPTION

Interreflected light, perceptual gloss and interpersonal evaluations are investigated by three recent LR&T papers that have been selected by Iain Carlile

TOAST OF THE TOWN

Andrew Bissell selects his Top Five cities in the second of a new series which sees lighting professionals choose exemplars of excellent lighting in different contexts

EVENTS

COVER: Mycelium, an illuminated acrylic wall by artist Nicolas Baier and GPI Design for Bay Street Bridge, Toronto, shortlisted for the exterior lighting category of the Surface Design Awards 2023

LIGHTING BODIES JOIN IN SIGNING EXTERIOR LIGHTING MANIFESTO

The Founding Partners of the Responsible Outdoor Lighting at Night (ROLAN) conference have come together to sign a manifesto for lighting professionals. It sets out 10 core principles for external illumination, and a plan of action 'to implement positive change in the lighting community':

1 Everyone should have the right to access darkness and quality lighting, and light needs to be used and distributed fairly without discrimination.

2 Start your design with darkness and only add light if it supports nocturnal placemaking and protects a view of the stars.

3 In all projects, strive to maximise the benefits of outdoor light at night by creating legible, safe spaces and journeys, simultaneously limiting each project’s environmental and financial costs.

4 Collaborate with researchers from different disciplines and specialties, such as astronomers, ecologists, biologists, lawyers and so on, so they can provide expertise on unfamiliar topics.

5 Educate clients about the importance of ROLAN.

6 Ensure the community you work with is an active stakeholder and participant in all lighting projects. Enquire about their needs and wishes at night, and provide them with access to information to make informed decisions.

7 Embrace technology by asking for support from the lighting industry to ensure that night-time biodiversity is sustained and energy consumption is reduced. Engage with the lighting design industry to deliver an appropriate lighting solution.

8 A circular economy should be integrated into the brief, design, specification and manufacturing process of your project, as well as its installation.

9 After project completion, visit the site at night with community stakeholders, to verify that your lighting design was fully implemented and meets ROLAN principles.

The principal authors of the ROLAN Manifesto for Lighting Professionals are Dr Karolina M Zielinska-Dabkowska of the ILLUME research group/Gdansk University of Technology and Ruskin Hartley of the International Dark‐Sky Association. Contributions and support have also been given by the SLL, the IALD, the IES, the ILP and the LIA.

'Because the UN Sustainable Development Goals do not explicitly refer to external illumination and its multiple impacts, the Founding Partners of the ROLAN movement are keen to address this in support of the SDG Goals,' said Zielinska-Dabkowska.

Any lighting organisation that would like to support the ROLAN movement should contact Dr Karolina M Zielinska-Dabkowska at: k.zielinska-dabkowska@pg.edu.pl

The inspiration for the Lego Luminaire came suddenly and painfully, according to Ambience MD David Justice. 'I stepped on a piece at 3am when going to the bathroom. The idea hit me as I was screaming really, really loud.'

Designed by Melbourne-based Ambience for its Symphony Lighting range, the 965mm-long Lego light is made entirely of the repurposed plastic bricks and emits light from a 7W LED through an opal

diffuser on the underside of the fitting.

It can either be suspended from the ceiling as a pendant, or balanced against a wall on the ground for a more nonchalant effect. But not where you might tread on it. https://ambiencelighting.com.au

French architect Odile Decq has designed a house with walls of translucent glass to create the optimal lighting conditions for a client with a vision impairment. The Maison de Verre, in Carantec, Brittany, was for a client who can only see vague shapes because of a progressive sight loss condition.

At his request, the light had to be homogeneous throughout and without glare. 'Entirely made of glass, the house is a box of natural light,' said Decq.

The walls are made of double panels of light-diffusing insulating glass (OKALUX K) between which the metal structural grid passes, becoming invisible. The textile tile included in its cavity allows shadowless lighting, with daylight penetrating deeply into the spaces.

The shape of the building – a parallelepiped (in other words all faces are parallelograms) dissected by a linear block – helps enhance the effect. 'The tilted shape allowed for the optimisation of the orientation of the glazed surfaces on the roof,' said Decq.

'The complete translucency of the walls, facades and roof, creates a singular phenomenon inside,' she added, 'a homogeneous and identical light at all points, an impression of a cocoon.'

The artificial lighting has been designed to create the same homogeneity with translucent pendants attached to the roof structure, complemented by a series of peripheral spotlights.

www.odiledecq.com/projets/threeexperimental-glass-houses/

PEOPLE IN GLASS HOUSES

MIND THE GAP

When Peter Fordham of Sainsbury's read a story that LEDs turned milk sour he decided to investigate further. The research looked at LEDs and no other sources. It used milk that spent a whole week in the cabinet –under unusually intense light. And it was paid for by a firm that makes an additive to plastic that turns it opaque.

The news item was hokum but it made headlines; however good, most research appears dull and arrives too late to make good copy, one reason, perhaps, for lower awareness among the public and funders than the industry imagines or needs.

‘The traditional route for research to influence practice is via standards and guidance but this is a slow process, added to which the timescales for research and industry can be very different,’ said Hoare Lea’s Ruth Kelly-Waskett, who chaired the recent SLL online panel discussion titled Agile Lighting Research – Bridging the Gap Between Research and Practice.

‘As designers, we want to gather evidence that is specific to the project or the demographics or the stakeholders that need to benefit from the design,’ argued panel member Florence Lam of Arup. ‘This is quite different from universities where the research is based on a defined set of subjects.’

‘It’s a learning experience for us all,’ admitted Surrey University’s Debra Skene. ‘Everyone uses different language and industry operates to different deadlines and timelines.’

It was important to apply evidencebased solutions, said Kelly-Waskett. While some clients want to experiment most want to know that their investment will be worthwhile, she pointed out. ‘When there’s a business imperative for research, we need agile models that allow shorter pieces of independent research.’

‘Applied research definitely has its place, and most manufacturers would be happy to discuss it with customers,’ said Sophie Parry of Trilux, ‘but there will always be a business case in the background.’

UCL’s Peter Raynham warned that the student shouldn't be 'over-steered' by the sponsor. ‘If you just followed what the sponsor said, you might always get an outcome that favoured their product.’

Evidence-based research is ‘all about codesigning,’ according to Skene. ‘We can avoid bias; if we use objective measures as well as all the self-reporting, we can completely design a project with all the right controls,’ she said.

Ultimately, the research ‘should be made available to everyone in the lighting industry,’ Parry observed.

Aside from taking part in Knowledge Transfer Partnerships and KT Networks, ‘one thing the industry can do, particularly large companies, is to work with academics to approach the research councils to ask for a tranche of PhDs over several universities, over several years,’ said University of Sheffield knowledge exchange manager Karim Sorefan. Research councils’ remits are broad and

lighting fits into at least three themes: design, electronics and manufacturing. Lighting research also crosses academic boundaries, encompassing psychology and biology as well as areas of technology. ‘Academic institutions have internal pots of money to invest in things that will have a big impact either on industry or policy,’ said CIBSE head of research Anastasia Mytona.

‘Very often when an idea for a research project comes it’s not fully formed,’ Raynham pointed out. ‘We can do pilot research to see if it’s a valid idea and then turn that around with relatively little funding and also get an answer quickly.’

Sheffield allocates more than £1m a year to pump prime projects, typically one to six-month projects often at no cost to the company. And while academics often work within a one to three-year timeframe, Sorefan added, funding known as an impact acceleration account, ‘allows rapid, dynamic funding of projects throughout the year.’

In the end, ‘you can talk about the topdown approach, where you want regulations to change and so on but it’s most important to think bottom-up and to create awareness with the people that you’re trying to help,’ said Christina Friis Blach of LYS Technologies.

SLL Agile Lighting Research – Bridging the Gap Between Research and Practice took place on 3 November 2022. To see the discussion in full go to: www.youtube.com/ watch?v=miy2rZ3gnqA

Chair: Ruth Kelly-Waskett, senior associate, Hoare Lea

Co-host: Shelley James, director Age of Light Innovations

Participants: Christina Friis Blach, CEO, LYS Technologies; Peter Fordham, electrical engineering design manager, Sainsbury's; Florence Lam, global lighting design director, Arup; Anastasia Mytona, head of research, CIBSE; Sophie Parry, head of Trilux UK Akademie; Peter Raynham, professor of the lit environment, UCL; Debra Skene, professor of neuroendocrinology, University of Surrey; Karim Sorefan, knowledge exchange manager, University of Sheffield

How can designers and manufacturers get the high-quality, evidence-based research they need? Francis Pearce reports on a recent SLL online panel debate that provided insights from both industry and academia

NATURAL SELECTION

All three of the awards in the latest Ready Steady Light competition, as usual coorganised by the SLL and Rose Bruford College in Sidcup, Kent, went to schemes that mainly focused on natural elements such as foliage and trees in the drama college's grounds.

Cundall won the technical award, judged by Andrew Bissell, SLL president, and Eliot Horsman, chair of the SLL marketing and communications committee.

The artistic award went to CBG Consultants, and was judged by Christopher Knowlton, IALD CEO, Emma Cogswell, IALD UK project manager, and Ben Ratcliffe, RBC subject leader in lighting design. Marlow Integrated Design (MID) won the peer prize, a coveted award judged by all the contestants taking part.

Taking place in its 19th year, Ready Steady Light is one of the society’s flagship events, providing 'a space for creativity and play, and a return to the basics of design and engineering'.

There were 13 teams participating in the event which took place last October. The teams of lighting designers, manufacturers and students – from the UCL light and lighting MSc course – are asked to create external lighting installations using a limited selection of lighting equipment and in only 180 minutes. The teams have to overcome challenges without a budget and within time constraints.

A key aspect of the event is that it provides an opportunity for students to gain some handson experience, experimenting with lighting techniques and working alongside practising lighting professionals.

Each year, the SLL puts out a call to lighting manufacturers who may wish to donate lighting equipment to Rose Bruford College, supporting their lighting education programme and students, along with future RSL events. If you are interested in finding out more or in donating lighting equipment, please contact the society (sll@cibse.org).

The winners of the latest Ready Steady Light competition all found their focus in nature

p From top to bottom: the winning schemes by Cundall, CBG and MID

Andrew Bissell: judging the technical award

Eliot Horsman and I visited each installation, both during set up and once it was dark. To be given just six light fittings and a random area of the campus is a tough gig. However, all the teams created something unique. By the end of the judging four teams were within two points of each other.

One team had lit an element high up on the tree, with a lowlevel light positioned, aimed and mapped to perfection to give the desired effect. Another team had used the gravel material of the land to create patterns and shadows to amplify the effect of the lights. We also saw a finesse in some of the gel use, with different shades and multiple gels used to create a swathe of colours in the landscape. A particular favourite of mine was the use of the trees as stage props to create the ‘prison bars’ which described the team's narrative of how they had felt through lockdown.

The winning team, however, just edged it with a few neat tricks. First, they had deliberately included darkness between the lit viewing position and the lit wall you viewed. Secondly, they didn’t shy away from lighting a fan coil unit and downpipe, they embraced those items and worked on getting the colour, beam angle, aiming and shadows spot on. They had the most difficult site and, in the opinion of Eliot and I, technically achieved the most on the night.

p Cundall, winner of the technical award (top), CBG, presented with the artistic award (centre), MID receiving the peer prize (above)

THE BOOK OF LIGHT

The new SLL Code for Lighting has just been released. Following a preview which appeared in Light Lines early last year, Sophie Parry outlines the updates which appear in the final version – and looks at how and why the Code has evolved since it first appeared in 1936

The Code for Lighting has an interesting history. The first edition was published by the Illuminating Engineering Society of Great Britain in 1936. In those days, the ‘Code’, as it is affectionately known, was also the sole publication containing all the application metrics for indoor and outdoor lighting, as well as chapters on first principles, calculations and metrology.

By 1985 the various IES regions around the UK had become part of CIBS, later to become CIBSE, and the Society of Light and Lighting was eventually the result.

In 2002, the EU’s CEN, jointly with the British Standards Institute, became responsible for indoor and outdoor lighting standards and so the now familiar BS EN series of standards started to appear. The SLL Code for Lighting continued to be published with periodic updating, and over several chapters included metrics by lighting application and in agreement with the BSi.

Where the Code adds extra value is that it also provides additional guidance notes on certain aspects of these metrics found in the reproduced BS EN lighting standards for indoor, outdoor and road lighting.

In addition, there are still all the chapters providing very detailed information and insights into lighting

first principles, calculations and metrology.

The Code is a comprehensive source of technical reference information for the lighting student, designer and engineer. I make no apology for ‘going technical’ – to understand the first principles of light and lighting requires some technical knowledge.

Curiosity is another useful attribute. If ever you want to know why you need to know about the first principles of lighting, then the Code will become essential reading. Like most subjects at a professional level, you think you know all about the subject until you really need to go deeper to find the answers, and at this point you begin to realise just how much more you have to learn.

So, if you are content to design and specify lighting by using a popular software package and accept ‘computer says yes’ or ‘computer says no’ outcomes then maybe it’s time to understand what else you can do as a student or a professional lighter to understand why the ‘computer says no’ and maybe even challenge your computer and prove it wrong.

The SLL Code for Lighting should not be confused with the SLL Lighting Handbook. The Handbook is the sister publication to the Code, and is more about design and project considerations and applications rather than first principles, although inevitably there is some dovetailing between both publications.

However, they complement each other in taking the reader on a journey from lighting theory and first principles to the understanding and delivery of lighting applications and solutions.

WHY DID THE CODE NEED UPDATING?

The Code was last published in 2012, about the time LED lighting was just making its debut but was still not the dominant light source. Since that time there have also been updates to the standards for daylighting, interior, exterior and road lighting, as well as changes to the minimum requirements

for lighting energy consumption, both via the UK Building Regulations and the growth of wholebuilding energy certification schemes.

From a scientific point of view, there has been some progress regarding the codification and metrics for the non-visual effects of light, with enough information available for melanopic content to be a design consideration. However, at the time of writing, there is still more research and codification required so it is prudent to stay informed about developments in this field.

In conclusion, not much stays the same in lighting for very long and the past 10 years have been no exception. The next 10 years will likely see a drive towards the codification and adoption of some new, key lighting metrics, as well as advances in the quality of delivered electric light.

KEY UPDATES

The first two chapters are overviews that establish the thought processes and philosophies relative to the deeper content of the Code.

Chapter 1 The balance of lighting

This chapter outlines the deliverables, impacts and costs (financial and environmental) associated with lighting and is written by way of introduction to the essence of the Code content.

Chapter 2 Light and human performance

This chapter outlines the benefits of lighting in terms of task lighting, human behaviours and how they can be affected or modified by lighting and the non-visual effects of lighting on people.

Chapters three through to eight are based on the current versions of BS EN lighting standards, with additional comment where appropriate to further assist the reader to make informed decisions on interpreting and applying the recommendations of these standards. Significant content relating to the metrics of the current standards has been reproduced with BSi permission.

Chapter 3 Indoor workplaces

This chapter has been updated in line with the revisions to BS EN 12464-1:2021 Light and lighting

– Lighting of work places – Pt 1: Indoor work places. There is additional commentary on some of the recommendations in the standard, as well as the inclusion of all 42 metrics tables by lighting application.

Chapter 4 Outdoor workplaces

This chapter has been updated in line with the revisions to BS EN 12464-2:2011 Light and lighting – Lighting of work places – Pt 2: Outdoor work places. There is additional commentary on some of the recommendations in the standard, information on environmental zoning and reducing light pollution, and the inclusion of all 19 metrics tables by lighting application.

Chapter 5 Road

This chapter has been updated in line with the revisions to BS 5489-1:2013 Code of Practice for the Design of Road Lighting and Public Amenity Areas, as well as the updates applied to BS EN 13201 parts 2, 3, 4 & 5 Road Lighting, which was published in 2015.

There is also comprehensive information on the application of these standards and links to further additional information.

Chapter 6 Daylight

This chapter has been updated in line with BS EN 17037:2018 Daylighting of Buildings. Daylighting is an important part of the lighting deliverable in the built environment and its quality is the benchmark standard that electric lighting should aspire to. However, working with daylighting involves taking into account many variables not encountered with fixed electric lighting and this chapter explains the nature of these variables and how to manage them.

Chapter 7 Energy and electric lighting

This chapter explains why lighting energy is a significant consideration when lighting in a sustainable way, with the need to support the decarbonisation of the built environment while maintaining the quality of delivered light. The method of calculating lighting energy in use is accurately modelled in BS EN 15193-1+A1:2021

Energy Performance of Buildings – Energy

Requirements for Lighting – Specifications, module M9. This is further applied to the Building Regulations example which is based on the current and most up-to-date Building Regulations Part L Conservation of Fuel and Power 2021 version for England.

There is also reference to optional energy certifications outside of the building regulations such as BREEAM, LEED and NABERS.

Chapter 8 CDM 2015 Regulations

This chapter explains the Construction (Design and Management) legislation in respect of lighting schemes and its relevance to lighting projects, and explains the obligations of clients, principal designers, designers, principal contractors, contractors, manufacturers and workers.

The following chapters cover the first principles of lighting physics and calculations, and also explain the relevance to lighting applications. The first principles have mostly remained constant since 2012 but the impact of light source technology adaption is factored into some chapters.

Chapter 9 Basic energy and light

This chapter covers light as a part of the electromagnetic spectrum, the energy contained within light, how light behaves, spectral, photopic and, the only addition, the melanopic or non-visual component of light.

Chapter 10 Luminous flux, intensity, illuminance, luminance and their relationship

Do you know the difference between illuminance and luminance? Quite simply, this chapter will provide the answers.

Chapter 11 Direct lighting

Ever wondered about the less obvious characteristics of light sources fixed to a ceiling and that point downwards? This chapter covers point, line and area light sources and the additional benefits of cylindrical, semi-cylindrical, spherical and hemispherical illuminance.

Chapter 12 Indirect lighting

So what happens when the light source is directed towards a surface such as a ceiling and the lighting solution is dependent on surface reflectances? This chapter covers the theory and application of Sumpners method, transfer factors and form factors. Here you will find a good example of how a lighting method can confuse software-based design tools due to the complexity of modern surface coverings, and why there is a need to know your first principles to validate your design.

Chapter 13 Photometric data sheets

Did you know that there is a series of BS EN standards that recommend how photometric data sheets are created and compiled? This chapter explores the BS EN 13032 series of standards and will provide useful first principle information on how a comprehensive and accurate data sheet should be written.

p 550 Madison, New York, by Gensler/KGM Architectural Lighting: Chapter 6 (Daylight) looks at the variables of working with natural light and how to manage them

p Dubai Route 2020 Metro link by dpa lighting consultants: Chapter 14 (Indoor lighting calculations) details the first principles of lighting in a spatial environment and looks at how to derive illumination values

Phil Handforth Architectural Photography

James Ewing

EChapter 14 Indoor lighting calculations

There is a lot more to indoor lighting calculations than just measuring the horizontal illuminance on a defined task area some distance above the floor and what happens when there is more than one light source required to light a space.

This chapter details the first principles of lighting in a more realistic spatial environment and looks at how to derive illumination values such as Planar, scalar, hemispherical, cylindrical and semicylindrical illuminances.

Chapter 15 Outdoor lighting calculations

Outdoor lighting calculations are not indoor lighting calculations. This chapter concentrates mostly on road lighting scenarios, as this represents perhaps the most important type of outdoor lighting in terms of safety, relative to the number of users.

In this chapter you will find information on how to determine glare, how surface reflectance can change, and why the previously mentioned terms semi-cylindrical and semi-spherical illuminances are important.

Chapter 16 Measurement of lighting installations and interpreting the results

This chapter examines how to measure the light output of a completed lighting installation that you may have designed or are asked to verify. It’s clear from the outset that an app on a mobile phone won’t cut the mustard here.

The specifications for illuminance and luminance meters are covered, as are the operating conditions under which measurements can be made, grids and illuminance measurement, and the measuring of road luminance and spatial illuminances as covered in chapters 13 and 15.

Chapter 17 Colour

This chapter is divided into two sections in order to explore the two critical factors that will help deliver colour in the way the designer wishes the viewer to perceive objects, both animate and inanimate:

• Colour properties of light sources

Chromaticity, colour temperature, colour rendering and the different methods for determining rendering, for example, CRI, Colour Quality Scale (CQS) and the IES TM 30-20 model

• Colour properties of surfaces

Munsell system, natural colour system (NCS) DIN system, BS 5252, RAL and CIE L*a*b* methods

Chapter 18 Predicting maintenance factor

We have all seen lighting designs with an MF of 0.8, but why is this so? This chapter explains how the maintenance factor for both indoor and outdoor lighting can be calculated and, more importantly, how to explain the reason why an MF other than 0.8 is being proposed.

Chapter 19 Glossary of Terms

Like most subjects, lighting loves a good acronym or obtuse term. This chapter lists all the acronyms and terms used in the Code and provides explanations and/or definitions.

Chapter 20 Appendices

A comprehensive list and referencing of all external legislation, standards, technical papers and guidance documents used in the Code.

So how do you update a 20-chapter publication? This has been a large project for the SLL’s technical and publications committee, and additionally there have been contributions from other SLL members and non-members.

The project has been ongoing for several years, but reached a critical point early in 2021 when there was enough update material created to justify bringing this project to a conclusion and while all the information in the SLL Code is still current. To the following list of acknowledgements, I would like to add Simon Robinson, immediate past chair of the SLL technical and publications committee, for entrusting me with the task of updating this key piece of guidance in UK lighting.

Acknowledgements

Project manager/editor in chief:

Sophie Parry, CEng MIET FSLL, head of Akademie, Trilux UK

Chapter authors and principal contributors:

Allan Howard, BEng (Hons) FLIP FSLL, group technical director (lighting), WSP

Peter Raynham, CEng MSc

MCIBSE FILP FSLL, professor of the lit environment, Institute for Environmental Design and Engineering, UCL

Sophie Parry (as above)

Peter Thorns, CEng BSc (Hons) FCIBSE FSLL, head of strategic lighting applications, Zumtobel Group Lighting

Ruth Kelly-Waskett, PhD CEng MCIBSE FSLL, senior associate, Hoare Lea, SLL past president Contributors and reviewers

Steve Fotios, PhD CEng MEI

MILP FSLL, professor of lighting and visual perception, University of Sheffield

Nigel Monaghan, FSLL, senior lighting consultant, Luminous Solutions

Peter Raynham (as above)

Peter Thorns (as above)

The SLL Code for Lighting is available free in PDF format for SLL members and at £84 for non-members. The hard copy version is £46 for members (£92 for non-members). It can be purchased/downloaded at: www.cibse.org/knowledge-research/knowledgeportal/sll-code-for-lighting

Technical secretary, SLL technical and publications committee John Fitzpatrick Editor

Ken Butcher, CIBSE Publications

Sophie Parry, FSLL, is chair of the SLL's technical and publications committee and a member of BSi Committee CPL/34/4 Luminaires among other roles. She is currently head of the Trilux UK Akademie

MEASURE OF PROGRESS

For the first time in its history Lighting Research and Technology has devoted an issue to one theme: Kit Cuttle and his proposal for a new approach to lighting design. Here he summarises the thinking which led to his LiDOs Procedure – and its potential evolution

The way in which we apply lighting technology for planning indoor lighting installations is off target.

The lighting standards that guide so much of general lighting practice specify the quantity of illumination to be provided as a value of task illuminance, but there are many types

 Four Seasons Bangkok at Chao Phraya River, lighting design by Project Lighting Design, winner of a 2022 IALD Award of Excellence – an exemplar of what LiDOs is aiming at: 'Its role is to encourage innovative and application-specific lighting solutions'

Sven Ellsworth

of indoor space for which there is no identifiable visual task to determine peoples’ needs for illumination. It simply makes no sense to require provision of illuminance to ensure efficient performance of a nonexistent visual task.

FROM TASK ILLUMINANCE TO AMBIENT ILLUMINANCE

Instead, the Lighting Design Objectives (LiDOs) Procedure is based on how people respond to the visible effects of the overall quantity of illumination within a space. In every lit space, the lighting creates a threedimensional luminous flux field that fills the volume of the space, providing the ambient illumination of that space.

This flux field consists of two visually distinct components. First, there is a direct component that comprises the flow of light from light sources (luminaires or windows) to points of incidence on room surfaces or objects within the space.

Secondly, the indirect component comprises the total first reflected flux (FRF) generated by the direct flux field, together with all the flux due to subsequent interreflections that occur until the FRF is totally absorbed.

The characteristics that make these two components visually distinct are that the direct flux field makes the light sources visible, and if this causes glare its effect would be to darken the overall appearance of the space. Conversely, the indirect flux field is the source of spatial brightness that provides for peoples’ visual experience of their surrounding environment. It is for this reason that ambient illuminance is defined as

the average density of the indirect flux field, and its metric is mean room surface exitance (MRSE) specified in lm/sqm.

SPATIAL BRIGHTNESS AS THE BASIS

Researchers have related peoples’ assessments of spatial brightness, expressed as how brightly lit or how dimly lit a space appears, to MRSE values. This research-based relationship provides the basis for lighting practitioners to specify ambient illuminance levels to create the spatial brightness levels that correspond to their chosen lighting design objectives. It also provides the basis for lighting standards to specify minimum ambient illuminance levels for categories of indoor locations that are based on typical assessments of spatial brightness.

Specification of selected spatial brightness in terms of ambient illuminance forms the basis of the LiDOs Procedure, and in fact, spatial brightness is the only lighting design objective that the practitioner needs to specify to apply the procedure. In doing so, the practitioner determines the quantity of first reflected flux needed to generate the indirect flux field within the space.

DIRECT FLUX DISTRIBUTION AS THE OUTPUT

That is the basis of the procedure. After that comes the question, how to plan the direct flux field that will generate the indirect flux field? In some cases, the lighting design objectives (LiDOs) may require only that the ambient illuminance is adequate for the activity that occurs in the space, in which case the procedure guides the practitioner towards an ‘illumination efficiency’ solution for which direct flux is distributed to generate the indirect flux field with optimal efficiency.

While efficiency is always a concern, other situations occur for which the practitioner will want to direct flux on to selected surfaces or objects to achieve an ‘illumination hierarchy’ comprising an envisaged distribution of visual emphasis. Several application-specific LiDOs may be needed to specify an illumination hierarchy. From these the procedure guides the practitioner towards deriving a direct flux distribution (DFD) that will generate the indirect flux field which will provide the intended spatial brightness with the envisaged distribution of visual emphasis.

While these concepts concern core

issues of the purpose for which we provide illumination within our buildings, there is another crucial way in which our current practice is off target. It all started with the Lumen Method, for which the lighting practitioner selects a luminaire, plans a layout, and performs a calculation to work out the average illuminance that the installation will provide over the horizontal working plane.

As more lighting criteria have been added, each requires a separate calculation to predict how the installation will perform. If the calculation for one of these added criteria, such as unified glare rating, indicates that the selected luminaire is unsatisfactory, the practitioner needs to restart the process. Experienced practitioners avoid this by choosing luminaires which, their experience tells them, will be acceptable for all the specified criteria, but inevitably, this inhibits innovation.

STARTING WITH LiDOs

The LiDOs Procedure reverses this process. The practitioner starts by identifying lighting design objectives relating to the quantity and distribution of illumination to be provided. Guidance is given on specifying these LiDOs in quantitative terms, and working from these values, the procedure guides the practitioner towards a specification of how the lighting installation is to direct luminous flux within the space to optimally achieve the combination of specified LiDOs. This is the direct flux distribution (DFD) which enables the practitioner to conduct an informed search for luminaires, and to devise layouts and control strategies to achieve the selected combination of LiDOs for each space. In this way, the procedure encourages innovative lighting solutions.

THE EVOLVING PROCEDURE

This describes the LiDOs Procedure in its present form, and more information and a worked example of application can be accessed online (see opposite for website). The procedure has caught the attention of some researchers and lighting design practices, and proposals for taking LiDOs up to another level abound. The special issue of Lighting Research and Technology draws together a selection of these ideas.

In the first paper, I propose that the procedure be extended for 'holistic lighting solutions' – the procedure should be able

'Spatial brightness is the only lighting design objective that the practitioner needs to specify to apply the procedure'

to cope with lighting design objectives that relate to the spectral and temporal distributions of illumination, as well as spatial distributions. This would enable practitioners to specify LiDOs relating not just to the familiar criteria of lighting standards, but also to other responses such as circadian effects and changing adaptation to daylight conditions, including ‘flow of light’ effects.

In fact, it should be able to cope with application-specific lighting solutions, for which several examples are illustrated. It is acknowledged that the computations involved would be beyond the scope of spreadsheets and that professional quality design software would be needed for this to happen.

The literature on brightness research is extensive, and usually concerns subjective assessments of the appearance of contrasting luminous fields under controlled viewing conditions. Spatial brightness is different in that it concerns how the overall quantity of illumination influences the appearance of a space, and it has only recently been established that spatial brightness is a function of ambient illuminance.

The study of assessments made in a small office reported by Durante and Kelly greatly extends the range of data on this functional relationship, and while there is still need for more studies in different types of locations, the prospect of providing practitioners with reliable guidance for specifying spatial brightness to satisfy the perceived adequacy of illumination (PAI) criterion has been brought a distinct step closer.

The authors also report the first investigation of the PAI criterion, and this is an important step towards lighting standards that specify minimum illuminance schedules specified in terms of a spatial illuminance metric, such as MRSE.

The calculation of spatial illuminance can be made straightforward by the application of Radiance software, but measurement faces two basic problems: how to capture the entire light field surrounding a point in space, and how to separate incident direct flux from indirect flux.

Researchers have successfully coped with these issues in laboratory situations, but a practical solution for verifying onsite conditions has not been available. The paper by Zhang, Li, Huang and Dai proposes a procedure for dealing with the first issue

by taking a series of 12 measurements within the space using a conventional illuminance meter to achieve a close approximation to the average value, while two papers by Li and Cai employ the recently developed 360-degree panoramic cameras to analyse the field of view surrounding a measurement point. These compact devices incorporate back-to-back 180-degree digital cameras to produce fullfield, high dynamic range (HDR) images as a single output file.

The authors explain how an illuminance meter, or better a luminance meter, can be used to calibrate these images as 360-degree panoramic luminance maps, enabling computation of a wide range of lighting metrics to be derived. As sources of direct light may be distinguished from their surroundings by their relative luminance values, incident direct flux can be separated from indirect flux to provide reliable measurements of spatial illuminance.

In a similar manner, the full-field luminance maps provided by these compact and robust devices would enable practical measurement and verification of a whole new range of novel metrics for lighting practice.

Finally, Boyce, Brandston and Cuttle review these concepts in the context of the lighting standards that guide current lighting practice. Without doubt, lighting standards have been very successful in overcoming inadequate and badly applied lighting practice, but the authors are critical of the notion that quality lighting can be achieved by adding additional criteria to the standards.

They illustrate examples of some successfully illuminated spaces and examine how their lighting compares with the criteria specified in BS/EN 12464-1:2021, using this standard as representing the most progressive among current lighting standards. Their conclusions propose that lighting standards should be enforceable, but should have a more restricted role, so giving more scope for practitioners to specify lighting design objectives leading to application-specific lighting solutions.

A NEED FOR PARTICIPATION

While the LiDOs Procedure is evolving with support from researchers around the world, there is need for yet more research and more reporting of practice-based experience. Perhaps even more than that, there is need for exploration and discussion among lighting professionals involved in indoor lighting practice.

Dr Kit Cuttle, FSLL FCIBSE FIESANZ FIESNA, is a lighting educator, designer and author

The special issue of Lighting Research and Technology (LR&T: Vol 54, Issue 7, November 2022) themed around the work of Kit Cuttle is now available: https:// journals.sagepub.com/toc/lrtd/54/7

Online versions of the following papers will be available to download free of cost until 23 May 2023:

Extending the lighting design objectives procedure for holistic lighting solutions, C Cuttle: https://journals.sagepub.com/doi/ full/10.1177/14771535211061044

Indoor lighting standards and their role in lighting practice

PR Boyce, HM Brandston and C Cuttle: https://journals.sagepub.com/doi/ full/10.1177/14771535221126413

Further reference

Details of LiDOs Procedure and a worked example of application: https://tinyurl.com/LiDOs-P

'The role of the lighting standard should be to eliminate bad options – just that and nothing more'

REFLECTION AND PERCEPTION

Interreflected light, perceptual gloss and interpersonal evaluations are investigated by three recent Lighting Research and Technology papers singled out by Iain Carlile

CYu et al have looked into the changing spectral properties of light as it interreflects within a space. The authors note that the effective light (the actual light in a space) can be defined as a complex light field, resulting from a combination of light from emissive light sources and indirect mutual surface reflections/interreflections.

The resultant light field therefore typically consists of diffuse and directional illumination, varying in spectral irradiance as a function of location and direction. The spatially varying differences in spectra result in correlated colour temperature (CCT) and colour rendition variances over the light field.

The study investigates the colorimetric properties of the actual light – or 'effective' CCT and colour rendition – for spaces of one reflectance (uni-chromatic spaces). Physical and simulated measurements for the spectra of the diffuse light-field component (light density) and directional light-field component (light vector) were taken.

The investigation revealed significant differences between the lamp-specified CCT and colour rendition, and the actual light-based effective CCT and colour rendition. The interreflections predominantly affected the CCT and colour rendition of the light density relative to the light vector, thereby demonstrating the importance of considering the materials in a space in context.

Tanaka et al’s paper examines the difference between physical gloss (as a physically measurable index) and perceptual gloss (a surface’s gloss as perceived by people). These differences occur because calculation of physical gloss is based only on specular properties and does not take into account physical features that may affect the perceptual gloss.

Measuring the properties of 127 flat objects, the authors analysed the relationship between physical features and the perceptual gloss. The flat objects consisted of three main material types: paper, resin and metal plating. Perceptual gloss was visually evaluated using a magnitude estimation method at 20, 60 and 80-degree angles. Physical features such as the gloss unit (GU), haze, distinctness of image, and high dynamic range (HDR) luminance were studied from which the authors constructed prediction models in order to predict the perceptual gloss.

Methods to improve the prediction accuracy were investigated through the use of the different physical properties and the GU in the power scale. The results from the study suggest that perceptual gloss may be related to brightness perception.

evaluations, it is not yet known whether the face is the most important visual cue.

Following a pilot study which showed the importance of being able to see a person’s face and hands, an experiment was conducted where test participants evaluated a photograph of an approaching person in night-time scenes. The photographs showed variations in the approaching person’s concealment of face (unobscured face, face concealed by hood and shades, lower face concealed by a scarf, and face fully concealed by hood, shades and scarf) and hands (exposed at the side of the body, exposed in front of the body, concealed in pockets, concealed behind the body).

Category rating and paired comparisons were used to evaluate the photographs. The results suggested that the face is more important than the hands when assessing the intent of other pedestrians at night.

Iain Carlile, FSLL, is a past president of the SLL and a senior associate at dpa lighting consultants

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)

Effects of interreflections on the correlated colour temperature and colour rendition of the light field

C Yu, M Wijntjes, E Eisemann and S Pont

Prediction model for perceptual gloss by physical measurement of flat objects

CCTs and lamp-specified CCTs (Yu et al)

Hamoodh et al have conducted a study which looks at how people assess the intent of other pedestrians after dark, investigating which aspects of a person’s appearance are most important for people to evaluate to support their feeling of safety. While past studies have investigated the degree to which road lighting supports facial identity and facial emotion

M Tanaka, S Amari and T Horiuchi

Visual cues to interpersonal evaluations for pedestrians

K Hamoodh, S Fotios and C Cheal

p Re lative differences between light-field

TOAST OF THE TOWN

In the second of a new series which sees lighting professionals choose exemplars of excellent lighting in different contexts, Andrew Bissell selects his Top Five cities

n the role we have as lighters and in a world where distance isn’t a barrier, we are generally lucky that in addition to overseas holidays we also get to travel for our clients and projects. Looking through photographs from the past 20 or so years has brought back some fantastic memories of truly beautiful places (day and night). Equally it has made me realise that I like everywhere I have been but for many different reasons.

I am not sure how I managed to get down to a list of five and I suspect if I did this again, I would select a different five. Also, doing this has reminded me how much I enjoy seeing new places and exploring how other people live and work. While I love the UK, and there are so many places there I still want to visit, there is something special about an overseas trip and as such all of my favourite cities are outside the UK.

I love the bustle of the centre of a city; however, I much prefer wandering off the beaten track into the back streets and residential areas. You learn more about a place and the people who live there. And the restaurants are always nicer.

Copenhagen

My first and indeed lasting impression of this city is how deliberate and meaningful the lighting is. The lighting is only there because it is needed. The spaces are not overlit and the lights themselves have a timeless elegance. Also, there is very little street clutter as a lot of the lighting is through catenary systems –something it would be good to see the UK adopt more of.

Hong Kong

It is the side streets and markets stalls which grabbed my attention in Hong Kong. Both incredibly bright and an utter mess yet at the same time it made me smile. I saw one stall with 6m of track and some 20 fittings on it. They couldn’t have got any more lights on there if they tried. Except on a recent visit HK lighting designer Minky Min found they had added four more runs of track

Detroit

The architecture rather than the lighting led me to put this city on my list. The glorious art deco buildings alongside modern blocks in the city centre, but all of it only a stone’s throw from derelict traditional American houses with steps up to the open porch. Sadly, I can't recall anything outstanding about the lighting, not even Comerica Park stadium lighting.

Tokyo

Sensory overload is the only way to describe Tokyo. Everything is lit. There are so many adverts you don’t know where to look first. During the day some areas are a mess with wires, brackets and control boxes on show. You have to wonder how it all works and doesn't catch fire. But after dark the mess becomes invisible. At night, it is all about the light.

Florence

The narrow streets have wall-mounted, oldfashioned lanterns which bring out the warmth and texture of the stone buildings. With so many restaurants tucked away in the narrow streets and with little or no signage to let you know where they are, you find yourself spotting the welcoming glow of the restaurant light long before you get there.

Unsplash

Min

Events 2023

For details of all upcoming webinars, go to: www.cibse.org/society-oflight-and-lighting-sll/sll-events/upcoming-webinars-and-online-content

For previously recorded CPD webinars (including regional webinars), go to: www.cibse.org/society-of-light-and-lighting-sll/sll-events/pastpresentations

ONLINE EVENTS

INTERNATIONAL INNOVATORS IN RESIDENTIAL HEALTHCARE NETWORK: BRIDGING THE GAP BETWEEN PRINCIPLES AND PRACTICE FOR CIRCADIAN LIGHTING

(online discussion organised by Age of Light Innovations and supported by the SLL)

Date: 7 March www.sll.org.uk

EVENTS

EUROLUCE

Date: 18-23 April

Venue: Fiera Milano, Milan www.salonemilano.it/en/exhibitions/euroluce

LIGHTFAIR

Date: 21-25 May

Venue: Jacob K Javits Convention Center New York

ENLIGHTEN EUROPE

(organised by the IALD)

Date: June 2023

Venue: TBC

AVAILABLE WEBINARS INCLUDE

RESPONSIBLE OUTDOOR LIGHTING AT NIGHT CONFERENCE 2022

All 44 videos, including introductions, presentations and panel sessions, are now available from the ROLAN website https://go.cibse.org/ROLAN22

AGILE LIGHTING RESEARCH: BRIDGING THE GAP BETWEEN THEORY AND PRACTICE IN HUMANCENTRED LIGHTING

(interdisciplinary debate sponsored by the SLL)

Curator: Shelley James: Age of Light Innovations

Chair: Ruth Kelly-Waskett: Hoare Lea

Panel: Peter Fordham, Sainsbury's; Christina Friis Blach, LYS Technologies; Florence Lam, Arup; Peter Raynham, UCL; Prof Debra Skene, University of Surrey; Karim Sorefan, University of Sheffield

SLL IN CONVERSATION (in assocation with Signify)

With Dr Eleonora Brembilla, assistant professor at TU Delft, and Dr Kynthia Chamilothori, assistant professor at Eindhoven University of Technology, who discuss their daylight research.