Making a Connection
Does the code allow fire alarm systems to interface with non-fire alarm systems?
NFPA Journal®, May/June 2013
Chapter 21 of NFPA 72®, National Fire Alarm and Signaling Code, covers emergency control function interfaces, or the interconnection of non-fire alarm systems with fire alarm systems.
The code defines emergency control function as “building, fire, and emergency control elements or systems that are initiated by the fire alarm or emergency communications system and either increase the level of life safety for occupants or control the spread of the harmful effects of fire or other dangerous products.”
Some of the more common non-fire alarm systems include elevator recall for firefighter service; elevator shutdown; fire service access elevators; occupant evacuation elevators; heating, ventilating, and air-conditioning (HVAC) systems; door and shutter release; damper release; release of electrically locked doors; and the actuation of exit marking audible notification systems.
The code further states that “emergency control functions are meant to be observed functions, not equipment or devices. Examples of emergency control functions are fan control, smoke damper operation, elevator recall, elevator power shutdown, door holder release, shutter release, door unlocking, activation of exit marking devices, and so forth. Fans, elevators, smoke dampers, door holders, shutters, locked doors, or exit marking devices themselves are not emergency control functions.”
In reviewing this language, some people have difficulty understanding that fire alarm systems interface with non-fire alarm systems in order to provide the performance of the emergency control function. In addition to these non-fire alarm systems, the owner may ask that the fire alarm system interface with still other non-fire alarm systems in order to monitor or control them.
An owner may wish to have the fire alarm system monitor unattended industrial processes that might operate out of control and damage the facility. Such processes include chemical overflows or heat damage to processing equipment. A non-fire gas monitoring system may need to interface with the fire alarm system to allow signaling to an off-premises monitoring facility to ensure a rapid response to dangerous conditions.
When interfacing any emergency control function to a fire alarm system, a number of requirements may apply. Emergency control funtions cannot interfere with other operations of the fire alarm system. Unless connected in a failsafe manner, emergency control function interface devices must be located within 3 feet (1 meter) of the component controlling the emergency control function. The emergency control function interface device must function within the voltage and current limitations of the fire alarm control unit. The installation wiring between the fire alarm control unit and the emergency control function interface device must be Class A, B, D, or X in accordance with Chapter 12. The method of interconnection between the emergency control function interface device and the component controlling the emergency control function must comply with the applicable provisions of NFPA 70®, National Electrical Code®, and be monitored for integrity.
Meeting these key requirements ensures that nothing that interfaces with the fire alarm system will adversely affect the operation of the fire alarm system. Fire alarm systems provide a vital fire protection function when they interface with non-fire alarm systems to provide important building emergency control functions or to monitor the safe operation of industrial processes.
Wayne D. Moore, P.E., FSFPE, is a principal with Hughes Associates.