Emergency lighting is lighting that stays on or automatically turns on to facilitate a building’s safe evacuation when it suffers a power outage. There is a trend of using light fixtures as both general and emergency lighting, and it presents special control considerations. POE LED for Emergency Lighting can and will be the standard.
Traditionally, emergency lighting design often entailed installing dedicated battery-powered emergency units, such as tungsten-halogen “bug eye” light fixtures. These light fixtures would provide the average 1 foot-candle of egress path illumination for at least 90 minutes as life safety codes require.
However, these light fixtures sit “dark” until needed, detracting from the space’s aesthetics. A growing number of projects eliminate the dedicated emergency light and use the same light fixtures for general and emergency lighting, delivering emergency power using battery, backup generator or uninterruptible power supply. POE LED for Emergency Lighting is a perfect example, due to the low power consumption of PoE LED Lights a facility is able to maintain all lights at full or half power for an extended period of time and not require huge battery banks to do so. Growth in solid-state technology, resulting in proliferation of light fixtures with built-in switching and dimming functionality, facilitated this trend. These dual-function light fixtures may be subject to automatic/manual control for energy management (energy codes) and visual needs, and the life safety code may require them to automatically activate at full brightness in the event of a power failure.
A variety of codes regulate emergency lighting. The two most prominent codes are NFPA 70, the National Electrical Code (NEC); and NFPA 101, the Life Safety Code. Other codes and standards may apply, including UL 924 (emergency lighting and power equipment), UL 1008 (transfer switches), the International Building Code, the International Fire Code, and NFPA 110 and 111 (standby power systems). Consult the authority having jurisdiction (AHJ) to determine the codes and standards that apply to a given project and how they’re interpreted.
The 2014 NEC added a requirement to Article 700 that directly controlled light fixtures used for emergency lighting to be listed (UL 924 certification) for use in emergency systems, which acknowledged use of light fixtures that provide both principal and emergency illumination without sacrificing control flexibility. Similar to the 2017 NEC, UL 924 defines “directly controlled light fixtures” as having the functionality to automatically override any control setting (e.g., dim, off) and establish an appropriate output illumination level in the event of a power failure.
The bypass device must be UL 924-listed, or if the bypass is integral to the control equipment and used on an emergency circuit, that equipment must be UL 924-listed. If a directly controlled light fixtures is used on an emergency circuit, it must be UL 924-listed as well. If a device is used to transfer to emergency power in either a feeder or branch emergency circuit, it should be UL 1008-listed.
UL 924-listed directly controlled light fixtures equipped with integral battery and loss-of-voltage sensing electronics can be controlled by remotely operated two-pole circuit breakers designed to provide power connections for both emergency and normal lighting.
“This application-specific circuit breaker helps engineers design emergency lighting systems that meet NEC Section 700.12 that requires the same branch circuit to feed both emergency power and normal power of the emergency lighting fixtures,” he said.
At PoE Lighting UK our entire PoE LED lighting system (Luminetworx) is connected to a ups unit with a battery pack ensuring at least a 90 minute run time during a power outage for the entire office and not just the exits. The system was designed with safety and energy efficiency in mind meeting all local and sate code requirements.