NFPA 72 defines a fire alarm system as a system or portion of a combination system that consists of components and circuits arranged to monitor and annunciate the status of fire alarm or supervisory signal-initiating devices and to initiate the appropriate response to those signals.
According to NFPA 72, “Fire Alarm Control Panel (FACP) or Fire Alarm Control Unit (FACU) is the brain of the fire alarm system, provided with primary and secondary power sources, which receives signals from alarm initiating devices or other fire alarm control units, and processes these signals to determine part or all of the required fire alarm system output functions(s) like alarm notification appliances.
NFPA 72, National Fire Alarm and Signaling Code, defines a detector as a device suitable for connection to a circuit that has a sensor that responds to a physical stimulus such as gas, heat, or smoke.
Fire Alarm Systems require an array of accessories to properly signal, alarm, notify, and complete fire alarm and detection activities.