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Fire alarm systems for K–12 schools
BY WAYNE D. MOORE
MOST STATE BUILDING, fire, and life safety codes now require all new K–12 schools to have manual fire alarm systems. In schools with more than 100 occupants, these systems initiate the occupant notification signal utilizing an emergency voice/alarm communications system that meets the requirements of, and is installed in accordance with, NFPA 72®, National Fire Alarm and Signaling Code. NFPA 72 does not require any type of fire alarm system to be installed in a building, but once a governing building code, fire code, or NFPA 101®, Life Safety Code®, requires any type of fire alarm system, the design and installation of the system must meet the requirements of NFPA 72.
Given the fact that the code only requires a manual fire alarm system in K–12 occupancies, the actuation of any manual fire alarm box will annunciate at the fire alarm system control panel, at any remote annunciator, and initiate a prerecorded notification message throughout the building. Under most circumstances, this notification message will indicate that all occupants should immediately evacuate. However, in certain circumstances, the authority having jurisdiction (AHJ) may approve or require other messages, such as the message appropriate for a high-rise building.
In addition, NFPA 72 permits the emergency voice/alarm communications system to provide other uses, such as for public address (PA) or mass notification purposes. When the system also serves a public address function, it might seem as if some features required for the PA system would violate NFPA 72 requirements. However, as long as emergency messages have priority over nonemergency messages, and all individual or zone speaker volume controls default to the emergency sound level when used for a fire alarm or an emergency mass notification message, the system will remain code compliant.
NFPA 72, Chapter 24, provides guidance regarding messaging. Subsection 24.3.6 requires first that stakeholders develop messages for each scenario noted in the emergency response plan, meaning that schools must have emergency response plans. Using a message template as defined in NFPA 72 and based on the emergency response plan, emergency messages must have content that provides information and instructions to the people in the building. An evacuation message must use the standard alarm evacuation signal consisting of a three-pulse temporal pattern with a minimum of two cycles preceding and following the voice message.
The codes also provide specific design requirements for the K–12 emergency voice/alarm communication systems. For example, the emergency voice/alarm communications system must have the capability to broadcast live voice messages by paging zones on a selective and all-call basis. Additionally, the codes permit the use of the emergency voice/alarm communications system for other announcements, provided the manual fire alarm use takes precedence over any other use. Both NFPA 72 and the codes require an emergency power supply—with the capacity to power the required load for a duration of not less than 24 hours—for the emergency voice/alarm communications systems.
It is important for designers, installers, and AHJs to understand that although all emergency voice/alarm communications systems required by the code must meet the requirements of NFPA 72, the governing codes and local jurisdiction amendments may dictate other design requirements. The operation of any automatic fire detector, sprinkler waterflow device, or manual fire alarm box must automatically sound an alert tone followed by voice instructions giving approved information and directions for a general or staged evacuation in accordance with the building’s fire safety and evacuation plans required by the jurisdiction’s fire code—“approved” meaning acceptable to the AHJ.
WAYNE D. MOORE, P.E., FSFPE, is vice president at JENSEN HUGHES.