Base zero lighting design
Sustainability Report 2014
by Mark Loeffler, Director
Recently, I needed to consult our jumbo copy of The Lighting Handbook, 10th Edition by the Illuminating Engineering Society. It is almost four inches thick and weighs about 10 pounds. It is the accumulated knowledge of the organisation that dubs itself ‘The Lighting Authority’. It is impressively massive and cumbersome, ironically not a ‘handbook’ at all.
It is also a metaphor for how lighting design is typically practiced. Conventionally, the emphasis has been on making buildings attractive. This has driven lighting designers to an approach that endeavors to maximize the lighting budget and energy allowance to create beautiful, photogenic architectural compositions while meeting standardized illuminance targets. As energy codes have become more stringent, designers who start with a ‘maximum energy’ approach will always be resentful of energy codes as a creative constraint.
Instead, we apply a different design philosophy that comes from the opposite direction that I have dubbed “Base Zero Lighting Design.” This means we start from scratch and build up a lighting system from baseline darkness. By beginning from zero light (and zero energy consumption) it is possible to develop a lighting design that serves the visual experience for the building occupants while using the least amount of equipment and energy consumption. By understanding the purpose of the building and the visual needs of its occupants, a designer can start by optimizing daylighting and task lighting, before adding accent lighting and ambient lighting, then finally a judicious application of decorative lighting. By lighting for people first, then for architectural effect, we can clearly prioritize design strategies. By treating light as a precious environmental resource, the fewest but most effective light sources, luminaires, and controls can be selected for the specific project, contributing to the ‘dematerialization’ of high-performance buildings.
This approach returns to the basics of building illumination before the advent of electric lighting. It is rooted in a fundamental understanding of ‘natural’ daylighting, supplemented by ‘artificial’ architectural lighting.
The human visual system is very accommodating. We can adapt to 100,000 lux of sunlight and 0.1 lux of full moonlight and everything in between. We naturally prefer a variation of luminance patterns over uniformity. We tend to like lighting of vertical planes to delineate interior space. Daylight is free, but must be treated with respect. Windows and skylights are not just simple openings in walls and ceilings. Daylight dynamically combines direct sunlight, indirect skylight, and diffuse cloudy light. It continually shifts – predictably by location, date, and time and unpredictably by climate and weather. Reflective interior finishes and smart space planning improve the effectiveness of daylighting and architectural lighting systems.
By clustering similar visual tasks and taking advantage of perimeter fenestration, lighting can be most efficiently organized and controlled. The smart selection of light sources and luminaires can provide suitable intensity, direction, diffusion, and color to supplement daylight during daytime and to create desirable visual environments after dark. New solid state luminaires and digital lighting control systems make this integrated design approach more feasible, affordable, and intuitive than ever before.
While this approach may seem obvious, it is sufficiently intriguing for me to be invited to speak at Lightfair in New York City in May 2015 on the topic. I will explore the design opportunities and challenges to putting this philosophy into practice, correlated with green building benchmarking programs and energy code compliance.