VOICES | AMBIENT LIGHTING Better ambient lighting design must be our focus The authors of the Ambient Lighting Manifesto insist that a change in methods of designing interior lighting is necessary and urgent. They explain why new metrics need to be adopted in codes and standards O ur Ambient Lighting Manifesto was published in the CIBSE Journal in December 2020, and a response from eight leading members of the profession was published in the March 2021 edition. We welcome the feedback from these highly respected lighters, and continue the dialogue with our response to their comments below, in no particular order. First, it is important for us to reiterate that changing workplaces, changing visual needs, the growing realisation that lighting affects health and wellbeing, and the demand to use energy wisely, mean that a change in our methods of designing interior lighting is necessary and urgent. This will never happen, however, unless we lift our eyes from the horizontal plane and develop better ways of | CALCULATION METHODS LIGHTING AMBIENT LIGHTING MANIFESTO: THE RESPONSE t lighting manifesto, written by four In December, CIBSE Journal published an ambien for a paradigm shift in lighting highly respected lighting academics who are calling the document from leading members practice. Here, we print a summary of reactions to on our website full in of the profession, whose responses can be read LIGHTING LIGHTING | MANIFESTO FOR | MANIFESTO FOR CHANGE CHANGE The ambient ifesto lighting man Kevin Kelly Boyce, Kit Cuttle, academics Peter Leading lighting to lighting practice fundamental change are calling for a P a often depends on science and technology way interior rogress in society, is needed in the must and we believe one paradigm shift we mean designers practised. By this lighting is generally give priority to lighting plane and, instead, on a horizontal working focusing on the visual tasks. than just the space rather for this belief: is delivered to perform a task There are four reasons information necessary required. Today, a lot of the illumination is not screens, so task through self-luminous and printing, good-quality photocopyingpower the availability of computer partly because of machine vision, of the growth in and partly because for human health and robotics. responses important the task to light visual and non-visual away from lighting Light generates is directing attention on a hypothetical a set illuminance and wellbeing. This of Lighting that delivers the main functions received at the eye. to what should be plane is irrelevant human health horizontal working visible and supporting the whole space lighting: making and Peter Raynham delivered to a nominal task illuminance means we will plane horizontal working money. save energy and miss a chance to Current practice by a number of is undertaken Lighting equipment from designers, groups, ranging and building manufacturers, architects to electrical contractors. services engineers and levels of expertise of These have varying streams, so the amount different income design varies but time spent on lighting They things in common. they do have two designs, to develop their all use software standards and they follow illuminanceinternational and produced by national poses a risk of bodies. To do otherwise of current practice The consequences a By designing for are many and varied. on a horizontal nominal task illuminance it is is delivered where working plane, light level that is not necessary. not needed at a is wasted. Further, In other words, energy as a lighting will be seen there is a risk that and where innovation simple commodity and price is everything. creativity are limited Left to right: Kevin Kelly, Kit Cuttle, Dr Peter Boyce and Professor Peter Raynham to quantify the nonbe a better way of the space. It would received by the eyes. peoples perceptions the amount of light lighting, as it estimates Design Objectives (LiDOs) procedure, visual impact of method, the Lighting of the lighting A suitable design to specify the objectives be determined and the practitioner can exists. It requires ambient illuminance this is done, the installation. Once cover situations values. This can illuminance ratio adjusting the target/ambient The objective shift, the lighting To achieve the paradigm by bodies such as standards produced from SLL must change ISO, CEN, CIE and illuminance uniformity illuminances and to minimum ambient on a horizontal plane of a space. It involves within the volume light in the distribution of consideration of to be expected to relate the space and can across a horizontal It will never happen unless all those involved lift up their eyes from the horizontal working plane working plane if that is the objective. professional manufacturers, regulators, are: support of designers, to be addressed We will need the Among the questions bodies and architects. practice be changed? How will lighting consumption? current practice? increase energy Will the change compared with the of ambient lighting What are the costs for the lighting industry? more working What are the opportunities and lighting designers Will it lead to architects the LiDOs procedure? closely together? be rewritten to support Can design software take? lighting standards What form should into the LiDOs procedure? be incorporated How can daylighting shift can occur: paradigm the desired lighting and are needed before Several activities for quantifying ambient essential. is suitable metrics 1 Research to identify for inclusion in standards human response of these metrics results in a better appropriate levels that ambient lighting 2 Research to establish illuminance meter. robust ambient of a reliable and 3 Development including any attempts 4 to current practice, approach relative ambient lighting How to get there 5 Hoare Leas lighting scheme for Barings, the horizontal plane, using uplighting volume (architect: 38 December 2020 TP Bennett) standards investigation. movement from and needs further be required if the on phase is likely to plane to ones based 6 A transitional have on a horizontal working standard would based on task illuminancesucceed. A transitional lighting and is to and uniformity) ambient illuminance practice (illuminance based on current would allow lighting and so on). This application tables (MRSE, MICI, TAIR, for a given project. they thought best for ambient lighting use whichever approach EN 12464-1, should prepare by practitioners to as possible. such as those revising approach as soon Lighting regulators, on the ambient lighting providing information eyes from the horizontal we must lift our CJ lighting to occur ambient lighting. for presented by For a shift to ambient see the opportunities working plane and University Dublin; and emeritus at Technological is editor of LR&T FSLL is professor PETER BOYCE FSLL KEVIN KELLY FCIBSEFSLL is a lighting consultant; DR at UCL KIT CUTTLE FCIBSEis professor of the Lit Environment PETER RAYNHAM om www.cibsejournal.c 2020 om December www.cibsejournal.c 39 Heatherwick Studio, Maggies, Leeds Left: The manifesto is published in the December edition of the Journal Barrie Wilde, retired lighting consultant, teacher, and former Society of Light and Lighting (SLL) president: Having retired recently, after 60 years as a lighting designer, these claims do not register with my own experience, or with that of the profession. Quite the reverse. The considerable number of highly successful, independent lighting-design building services, consultancies including specialist lighting units in an enlightened design and architectural practices already operate design ethos of ambient, task, display. Of course, there are still lighting designs based on spraying a horizontal surface with an abundance of luminous flux, but surely this is a case for education, not a wholesale change in the metrics? The SLL presidents address of 2005, by lighting the academic and researcher Geoff Cook, was titled Mind gap, and addressed the widening gap between research is and design. This manifesto perhaps indicates that there shift still a disconnect between the two and, if a paradigm to is really necessary, it should be to close this gap, not produce yet another set of metrics. 36 March 2021 www.cibsejournal.com 19/02/2021 15:20 The response to the manifesto of eight leading lighting professionals, in the Journal in March 2021 CIBSE March 21 pp36-38 Lighting manifesto response.indd 36 designing lighting that respond to these changing needs. Continuing to design lighting using illuminance on a plane as the central metric is inappropriate and will not allow us, as a lighting and engineering community, to move forward. Our manifesto has set out our beliefs. If you put the four of us in a room, we would probably not agree on very much. However, we do agree on this manifesto, because there is growing evidence based on multiple PhD theses and published papers that the ambient lighting metrics originally proposed by Kit Cuttle are valid, robust and reliable enough to justify their widespread use. It is argued that lighting designers already consider ambient lighting; maybe it is true that some do, but a lot of design in the industry is still based around a 100-year-old metric for working-plane illuminance. Even if lighting designers already do consider ambient lighting in practice, the new metrics mean room surface exitance (MRSE) and task/ambient illuminance ratio (TAIR) coupled to the Lighting Design Objectives Procedure (LiDOs), offer new tools for design and to prove compliance when codes and standards include these metrics. This is already beginning to happen. In this way, we do indeed support what leading lighting designers are already doing. A very good point was made about closing the gap between research and design, and this is what our manifesto set out to do. This continuing dialogue, and the engagement of practitioners, furthers this aim. As researchers and academics, we are aware of the research published and the research coming through for publication. Without this research, there would be no evidence to support the change to the new paradigm represented by LiDOs. And it is a new paradigm a whole new way of doing things. It starts with listing the lighting design objectives in descriptive terms that everyone can understand, and this can be as simple or as complex as circumstances demand. Then, the practitioner specifies those objectives relating to illumination quantity and spatial distribution in terms of the metrics, and the procedure guides the user towards a specification of the required lighting performance. This specification enables an informed selection of light sources, luminaires, and layout, with confidence that the chosen objectives will be achieved. If LiDOs shifts standards towards what advanced lighting designers are already doing, that can only be a good thing. Another question raised was, is this moving from design to auto design? No, is the answer. There may be moves 24 May 2021 www.cibsejournal.com CIBSE May 21 pp24-25 Ambient manifesto.indd 24 23/04/2021 15:57