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Is there a dark side to biologically effective lighting?

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Biologically effective lighting is a form of artificial light that is modelled on natural light. It is intended to contribute to safe, healthy and productive workplaces. Variation of the colour temperature is a particular means by which this is achieved. OSH experts however still have their reservations when it comes to binding regulations governing the technology, since it may also be associated with risks, and results from long-term studies are not yet available.

A pleasant sunny day has a positive influence on mood. It is bright, it is warm, and as a result we feel good. We are all aware that daylight has other, positive effects on us besides that of simply illuminating our surroundings. Researchers and designers have therefore been trying for many years to understand daylight and its diverse and dynamic properties, in order to recreate it artificially and to use it for various purposes, for example at workplaces. These include stabilization of the circadian rhythm, or increasing of workers' capacity for performance.

Within DIN's Lighting Technology Standards Committee, numerous experts on biologically effective lighting have joined forces in the working committee responsible for the effect of light upon human beings. Their aim is to gather recognized knowledge on the non-visual effects of light and to make it available through standards.

The correct dose is crucial

The delegates to the seventh DIN Expert Forum, hosted by the standards committee in June 2013, were however not in agreement on whether biologically effective lighting had already been sufficiently developed for general use. A small number of major manufacturers in the lighting industry have already adopted a proactive stance and launched the first products on the market employing biologically effective lighting, dynamic light, or light adapted to the natural (circadian) daily rhythm as their unique selling points. Measurable long-term effects, and relationships between certain properties of light and the associated effects, are however still not generally recognized. In addition, the technology raises new ethical questions. Attempts could for example be made to use blue light in order to increase productivity or to influence human beings deliberately by other forms of "light doping".

The advocates of the technology point out that owing to their working hours or the nature of their workplaces, employees' access to daylight has long been limited. Supplementary biologically effective light is, they argue, therefore healthy and beneficial. The real question is however whether the entire daily dose of light is in fact the relevant factor and whether leisure time and working hours should therefore be given equal consideration.

During leisure hours, people are free to decide for themselves what light sources (such as candles, sunlight, or indeed biologically effective lighting) they choose to expose themselves to, and for how long. By contrast, scope for personal influence is more limited at the workplace. Responsibility for the consequences of defined environmental factors such as sources of light is therefore also regulated differently. Requirements for employers concerning lighting are formulated in technical rules governing workplaces. These provisions, which are binding, are intended to assure the occupational safety and health of all workers.

Dialogue is needed

With their practical character and their greater level of detail, standards may be able to support the technical requirements applicable to workplaces. The precise mode of action and possible areas of application of biologically effective lighting have however not yet been clarified conclusively. For this reason, the only normative document to date is DIN SPEC Technical Report 67600, "Biologically effective illumination – Design guidelines", which documents the results of the standards committee's work obtained to date.

It is undisputed that daylight in general has a positive effect upon the health and well-being of human beings1. How, then, should the deficit be rectified for people who are not able to work in daylight? The technical requirements that must be met by biologically effective lighting in order for it to be fully effective yet without influencing employees unacceptably in their behaviour have yet to be established.

KAN is engaged in dialogue with representatives of the social partners, German government bodies, the German Social Accident Insurance (DGUV) and DIN regarding the possible content of a future standard from the perspective of occupational safety and health and whether aspects of biologically effective lighting might even be included in binding provisions (such as the ASR 3.4 technical rule for workplaces).

Dr Dirk Bartnik
bartnik@kan.de

1 Technical Rule for Workplaces ASR A3.4, Lighting www.baua.de/de/Themen-von-A-Z/Arbeitsstaetten/ASR/ASR-A3-4.html (in German)
BAuA on biologically effective lighting:
www.baua.de/en/Research/Research-Project/Ambient-Intelligence/Project-Bundle-6_content.html