ABSTRACT
Certain types of occupancies are required to have automatic or manual fire alarm systems by the National Fire Protection Association (NFPA) Life Safety Code and model building and fire prevention codes. Fire alarm systems may also be installed even if they are not required by any code. All that is required is a good job of salesmanship by the authority having jurisdiction (AHJ). The primary purpose of a fire alarm system in an occupied building is to alert occupants to a fire and start a timely evacuation of the building. Fire alarm systems can also be used to evacuate a building for other types of emergencies that are not fires, such as chemical releases and gas leaks. A fire alarm system consists of interconnected automatic smoke, heat and fire monitoring devices, manual activation devices, notification devices, and auxiliary controls. The system is designed to alert building occupants to fire or dangerous conditions and provide emergency responders with information about those conditions. Clear and concise information will enable responders to operate efficiently and safely at an incident scene. Fire alarm systems monitor alarm-initiating devices such as manual pull stations; automatic smoke, heat, and fire detectors; or water flow indicators. Fire alarms also interface and control elevators and building HVAC systems as well as smoke control and smoke evacuation systems. Fire alarm systems operate in the following manner: When a signal is received, the control components process it via software programs or relays. The system then activates audible and visual evacuation notification devices; sends a remote signal to the fire service or other authorities; displays the location of the alarm; recalls elevators; shuts fire doors on magnetic hold-open devices; initiates smoke control systems; starts stair pressurization; and controls ventilation systems. 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 by-products. Detection systems are often integrated into fire alarm systems, and both will be covered in this chapter.
