When upgrading or redesigning commercial outdoor lighting systems, many companies face the question of what the lighting levels should be for their various outdoor areas. Is there a minimum safety requirement for foot pathways? Is there a suggested lighting level for parking areas that will increase security? Depending on your specific locale, the guidelines for choosing appropriate outdoor lighting levelsmay be based on a complex combination of both mandated building regulations, and best industry practice and recommendations.
Location is Everything
At its most basic level, the purpose of outdoor lighting is to enhance both public safety and security. The ideal aim today is for this to be accomplished with as great a level of energy efficiency, and as little contribution to the hazards of light pollution, as possible. Across Canada, outdoor lighting for built structures and private areas is enforced by various building and municipal codes that take their cue from recommendations provided by the Illuminating Engineering Society of North America (IESNA). These codes help to determine the illumination levels, location and use for outdoor lighting, but they are not yet standardized.
While national building codes in Canada suggest that all exterior lighting have automatic controls that turn it off when daylight is available – exempting large, covered areas like parking garages – specifics of lighting levels still fall under regional jurisdiction. In the city of Toronto, for example, the municipal code states that commercial walkways, parking lots, loading docks and ramps should maintain a minimum level of illumination of 10 lux, or 1 foot-candle, at ground level, at no more than a 10:1 uniformity ratio. Lux (lx) and foot-candles (fc) are simplythe metric and imperial measurements of light intensity, while the uniformity ratio describes how evenly that light is dispersed over a given area. The lower the ratio, the more evenly distributed the illumination is.
Adopting Advanced Lighting Practices
But because most outdoor lighting policies were developed with the concern for safety and security first and foremost, they have yet to fully embrace recommendationsrelated to minimizing energy usage and light pollution.With the current LED technology revolution, however, these themes are slowly but surely making their way into the jumble of outdoor lighting codes and regulations. Valuable research put forward by groups like The Lighting Research Centre (LRC) in New York, and education offered by public awareness proponents like the International Dark-Sky Organization, are beginning to make an impact on policy-makers. Some jurisdictions, like Toronto, have already introduced requirements for appropriately shielded and directed light sources to minimize the negative effects of glare and light trespass.
Earlier this year, the LRC presented noteworthyfindings that indicated effective LED lighting levels for parking lots are more determined by their uniformity than by their intensity when it comes to establishing a sense of security. Their research found that people had the same perception of safety with 9 lux and a 3:1 ratio of lighting uniformity as they did with 40 lux and a 10:1 ratio. The widespread standardization of optimal outdoor lighting levelsbased on important research such as this may soon go a long way toward recognizingsignificant energy and cost savings nation-wide.