Question
What types of emergency lighting are listed by UL under the product category Emergency Lighting and Power Equipment (FTBR)?
Answer
Luminaires that are specifically for use as emergency lighting are listed under the product category Emergency Lighting and Power Equipment (FTBR), located on page 142 in the 2009 UL White Book. Luminaires listed under (FTBR) would be evaluated for compliance with the Standard for Safety for Emergency Lighting and Power Equipment, UL 924.
Other than exit signs, the most commonly known emergency lighting product is Unit Equipment; they are typically the two-lamp assemblies mounted to a battery pack that illuminate only during power outages or alarm signal events. UL 924 also covers emergency luminaires, which could be of one of two types:
1. Integral emergency battery pack system (inverter/ charger pack)—the luminaire has only one connection to the facility power source (normal utility power). When the normal power drops out, the on-board battery pack kicks in. These are essentially “normal” UL 1598, The Standard for Safety for Luminaires, listed luminaires with a UL 924-listed inverter charger pack, test switch, and indicator lights added either at the luminaire factory or in the field. In most all cases, the inverter/charger pack is sized to feed only the lamps within that luminaire, although it is possible to oversize the pack and feed an adjacent / additional luminaire. However, in most cases, the emergency circuit would not leave the luminaire that houses the inverter/charger pack.
2. Dual power source connection—two separate lead wire sets, one from the utility and a separate set from the emergency source, each energizing separate lamps within the luminaire. This construction is relatively uncommon today, typically due to improvements in luminaire efficiency and the expense of including emergency components that sit idle most of the time.
The standard for “normal” luminaires, UL 1598, does allow for the inclusion of a back-up battery; however, it does not evaluate the power capacity of that battery and thus those luminaires are not permitted to be marked as “emergency luminaires.”
