Tillotson Design Associates bundled more than 10,000 lamps into groups of four individual sockets to create an industrial style fixture at R/GA's headquarters, in New York. Photo: John Muggenborg
Natural is often best, and that statement is also true when it comes to illuminating interiors. However, daylight must oftentimes be supplemented with electric light to meet code requirements and provide adequate lighting around the clock, particularly in environments in which people spend significant amounts of time, such as workplaces, schools, and healthcare and senior living facilities.
Newer editions of building codes factor energy conservation in their lighting specifications, but scientific studies have also connected quality of light to human health and well-being; that is, lighting needs to meet both the visual and non-visual needs of occupants. The relatively new concept of human-centric lighting encourages lighting designs that balance visual, emotional, and biological benefits, regardless of the source of the light.
What the Codes Say
Currently, building codes that prioritize energy efficiency place a premium on lighting power density (LPD) limits. These codes establish maximums, expressed in watts per square foot, that can be defined by space to space, whole building, or performance target.
For more than 35 years, ANSI/ASHRAE/Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings has been the benchmark for commercial building energy codes, and it is the basis for the International Energy Conservation Code (IECC). Many jurisdictions have adopted the IECC; the highly populated states of California and New York have even implemented more stringent requirements aimed at conserving a greater amount of energy.
Because lighting should both integrate with and enhance the overall building environment, architects often turn to experts—lighting designers, M/E/P engineers, and lighting manufacturers—to calculate appropriate, code-compliant lighting levels using sophisticated software packages, and to recommend fixtures. At the same time, lighting manufacturers are continually challenged to produce new luminaires that meet ever-evolving code requirements.