Codes and Standards
Although state and local building codes vary, most are based upon:
- The National Electrical Code®, NFPA 70, Article 700;
- The Life Safety Code®, NFPA 101, Sections 7-8 through 7-10;
- The Occupational Safety and Health Act (OSHA), which offers some general guidelines.
"Emergency illumination shall be provided for not less than 1½ hours in the event of failure of normal lighting. Emergency lighting facilities shall be arranged to provide initial illumination that is not less than an average of 1 ft-candle (10 lux) and, at any point, not less than 0.1 ft-candle (1 lux), measured along the path of egress at floor level. Illumination levels shall be permitted to decline to not less than an average of 0.6 ft-candle (6 lux) and, at any point, not less than 0.06 ft-candle (0.6 lux) at the end of 1½ hours. A maximum-to-minimum illumination uniformity ratio of 40 to 1 shall not be exceeded."
It is important to remember that code requirements reflect minimum standards and, therefore, are generally considered only a starting point in designing emergency lighting systems. Additional emergency lighting, beyond minimums, is warranted in some facilities, depending upon facility use and other relevant factors. Hospitals and nursing homes, for example, are excellent candidates for additional emergency lighting. The same is true of manufacturing and production areas, which often present numerous potential safety hazards even under the best of conditions.
Codes mandate, among other actions and standards, periodic monitoring of emergency lighting equipment once it is installed. Emergency operation must be tested monthly (30 seconds) and, for battery-powered sources, annually (90 minutes) in order to meet the NFPA's Life Safety Code (see Section 7.9). Moreover, the NFPA requires that written records of these tests and their accompanying visual inspections be kept as proof of maintenance (see the Life Safety Code, Section 7.9 and the National Electrical Code, Article 700). Because this emergency equipment is used only on an emergency basis, it is important that regular maintenance be performed. As with all capital investments, upkeep is vital and provides proof when liability questions arise. Common sense must be used in planning emergency lighting systems. The major objective of adequate and reliable emergency lighting is to help ensure occupants a safe, panic-free exit from a building in the event of a power failure.
This section contains a revision of portions of a 1977 article written for EC&M by former Bodine Emergency Lighting CEO David Crippen.