Fire Alarm Systems

GENERAL


A fire alarm system consists of interconnected devices and controls to alert building occupants to fire or dangerous conditions and provide emergency responders with information on those conditions. Clear and concise information will enable responders to operate efficiently and safely.

Fire alarm systems monitor alarm-initiating devices such as manual pull stations, automatic detectors, or water flow indicators (Figure 6.1a). If a signal is received, the control components process it via software programs or relays (Figure 6.1b). The system then activates audible and visual evacuation notification devices (Figure 6.1c); sends a remote signal to the fire service or other authorities; displays the location of the alarm; recalls elevators; and controls ventilation systems.

 

(Fig. 6.1a) Initiating device (smoke detector).(Fig. 6.1a) Initiating device (smoke detector).

 

(Fig. 6.1b) Control panel.(Fig. 6.1b) Control panel.

 

(Fig. 6.1c) Notification device (horn/strobe).(Fig. 6.1c) Notification device (horn/strobe).

 

Systems can vary widely in complexity. A basic, fundamental system consists of a control panel, initiating devices, and notification devices. On the other end of the spectrum are complex selective voice evacuation systems with integrated fire department phone communications systems. Detection systems have devices that automatically sense fire or its byproducts. Detection systems are often integrated into fire alarm systems, and this chapter covers both.

Building and fire codes often specify requirements for fire alarms systems. Commonly used codes include the IBC, NFPA 5000, and NFPA 101. The National Fire Alarm Code, NFPA 72, is a comprehensive installation standard. This code, along with the fire alarm wiring portion of the National Electric Code, NFPA 70, sets the requirements for design, installation, and maintenance. In addition, OSHA standards create obligations with respect to employee alarm systems.

This chapter covers fire service personnel interaction with fire alarm systems and provides guidance for designers to facilitate operational efficiency. Elevator control, often interconnected with the fire alarm system, is discussed in the section, Firefighter Access, on page 21. The section, Smoke Control Systems, on page 63, covers these systems.