Types of Supervising Stations
Chapter 26 of NFPA 72 governs supervising station alarm systems, which provide off-premises monitoring of fire alarm signals. There are three main types: central station service, proprietary supervising station service, and remote supervising station service. Central station service is the most comprehensive, requiring a listed central station that meets specific staffing, equipment, and operational standards. Proprietary systems are owned and operated by the property owner and monitor multiple buildings at a single campus or facility. Remote supervising stations receive signals at a location such as a fire department or third-party monitoring center.
Central Station Service
Central station service has the most stringent requirements. The central station must be listed by a nationally recognized testing laboratory, staffed by trained operators at all times, and equipped with redundant signal receiving and processing equipment. Upon receiving an alarm signal, the central station must retransmit the alarm to the fire department within 90 seconds. Central station service also requires runner service, where a trained representative is dispatched to the protected premises upon receipt of an alarm, supervisory, or trouble signal.
Signal Transmission Technologies
Signals between the protected premises and the supervising station may be transmitted via various technologies, including telephone lines, cellular networks, internet protocol (IP), radio, and mesh networks. Each transmission technology must meet specific performance requirements for reliability, speed, and supervision. The transmission path must be monitored for integrity, and faults must be reported within defined time limits, typically 200 seconds for most technologies.
Response and Documentation
Chapter 26 specifies required response actions for each signal type. Alarm signals require immediate retransmission to the fire department. Supervisory signals require investigation within a defined timeframe. Trouble signals require notification of the building owner and corrective action. All signals and actions must be documented and retained. Supervising station operators must follow written standard operating procedures approved by the authority having jurisdiction.
