What you need to now about alarm and sprinkler requirements in industrial occupancies
NFPA Journal®, March/April 2012
Industrial occupancy fire alarm systems face somewhat different challenges than systems found in other occupancies. Industrial occupancies frequently store hazardous materials or use them in manufacturing operations. In addition, other authorities having jurisdiction (AHJs) often have additional requirements for the fire alarm system than those included in NFPA 101®, Life Safety Code®. For example, property insurers typically include requirements to ensure rapid notification of both in-house fire brigades (if provided) and the local fire department.
Once NFPA 101, NFPA 5000®, Building Construction and Safety Code®, or some other private AHJ requires a fire alarm system for an industrial occupancy, such requirements typically insist on compliance with NFPA 72®, National Fire Alarm and Signaling Code, and NFPA 70®, National Electrical Code®, to ensure operational integrity.
In general, most new industrial occupancies will be protected by an automatic sprinkler system. The codes require the fire alarm system to monitor the operational readiness of the automatic sprinkler system and initiate an alarm when the sprinkler system operates. In addition, NFPA 72 requires the installation of at least one manual fire alarm box, the location of which is directed by the AHJ. Depending on the hazard classification of the occupancy, the alarm will consist of either a positive alarm sequence that sounds an audible and visible signal in a constantly attended location to allow a limited time for investigation before a general alarm sounds, or a general evacuation alarm. Existing systems are permitted to have pre-signal alarm systems, in which the alarm sounds only at predetermined locations until someone in authority initiates a general alarm.
Code requirements for industrial occupancy fire alarm systems are straightforward. However, the monitoring and additional supervision requirements of the fire alarm and automatic sprinkler systems mandated by some insurers could surprise designers and installers, who must take care when determining the extent of the fire alarm system design and its operation.
Some industrial occupancies contain hazardous materials storage areas that may have special hazard fire protection systems installed to protect the hazard. The building fire alarm system must monitor these systems as well. Occupant notification is also straightforward. In some instances, owners may desire a voice evacuation system to better inform occupants about their evacuation or relocation to a safer area.
Industrial occupancies must also conform to the requirements of NFPA 90A, Installation of Air-Conditioning and Ventilating Systems. NFPA 90A requires duct smoke detectors downstream of the air filters and ahead of any branch connections in air supply systems with a capacity greater than 2,000 cubic feet (57 cubic meters) per minute in and at each story before the connection to a common return, and before any recirculation or fresh air inlet connection in air return systems with a capacity greater than 15,000 cubic feet (425 cubic meters) per minute and serving more than one story.
The smoke detectors must also be connected to the fire alarm system in accordance with NFPA 72. The code also requires that automatic smoke detection be installed in areas not continuously occupied to provide notification of fire at each fire alarm control unit, notification appliance circuit power extender, and supervising station transmitting equipment.
Although the industrial occupancy section of NFPA 101 does not mention notifying emergency responders, most designers and installers will find that other AHJs will require connection to a supervisory station, which is typically a central station.
Wayne D. Moore, P.E., FSFPE, is a principal with Hughes Associates.