We’ve been looking for a term that encompasses the approach that we need to take to achieve a healthful lighting environment. ‘Human Centric Lighting’ is all but discredited since its been picked up by marketing departments and used as a convenient tag for anything containing tunable white LEDs, so we’re obliged to look for something more appropriate to describe what we’re trying to do.
While we’ve been thinking about it, the CIE has already gone ahead and done the work for us. The term that we’ve been looking for is Integrative Lighting.
Defined as ‘lighting specifically designed to produce a beneficial physiological and/or psychological effect upon humans’ the term Integrative Lighting both opens out what Lighting for Health might mean, while at the same time focusing on a very important factor – that for lighting to be successful in a healthful environment it must be seen as a component part of the broader Wellness environment – it must be integrated into the whole.
Lighting does not make a healthful environment; it is part of an overall strategy for Health.
Integrative Lighting embraces the visual and non-visual effect of lighting. In those respects we need to consider all of the impacts that lighting can have on us; and its starting point must be Do No Harm. A proper Integrative Lighting scheme must take into account:
- The effects of glare within the lit environment
- Flicker in LED lighting, which is finally being recognised as a source of potential health problems
- The impacts of the spectral power distribution of light, both in its blue content, but also in any potential risk posed by the introduction of UV through the growing use of violet LEDs in ‘daylight’ LED products.
- The distribution of light in space, in particular the balance of direct and indirect illumination
- The ability for the individual to control their personal lighting environment
- We might also add that Integrative Lighting also makes optimal use of daylighting
Jennifer Veitch of the National Research Council Canada has defined a number of design conditions for ‘healthful lighting’:
- 1. The daily light dose received by people in industrialized countries might be too low.
- 2. Healthy light is inextricably linked to healthy darkness.
- 3. Light for biological action should be rich in the regions of the spectrum to which the non-visual system is most sensitive.
- 4. The important consideration in determining light dose is the light received at the eye, both directly from the light source and reflected off surrounding surfaces.
- 5. The timing of light exposure influences the effects of the dose
Veitch’s guiding principle is that Integrative Lighting is design-led – not product driven. Integrative Lighting is necessarily a dynamic principle; it answers client needs. Schemes should be built from evidence-based design findings, not simply imposed from one-size-fits-all codes and standards. It also calls for on-going analysis of the impacts of schemes once they are put in practice. We are desperately short of real-life analyses of ‘healthful’ lighting installations. Post-occupancy evaluation is the method whereby we can determine the true success of the principles behind Integrative Lighting.