An automatic fire alarm system is a type of automatic fire-protection facility installed in buildings or other premises for the purpose of detecting and reporting fires at an early stage and taking effective measures in a timely manner to control and extinguish them. In many developed countries, the production and application of automatic fire alarm devices or systems are very widespread.

An automatic fire alarm system generally consists of trigger devices (such as fire detectors and manual fire alarm buttons), fire alarm devices, fire warning devices, and a power supply; more complex systems also include fire control equipment (such as fire-extinguishing control devices, linkage control devices for elevators, fire shutters, etc., fire emergency broadcast and fire communication, emergency lighting, and other control equipment). It is a kind of ... integrating automatic fire detection, automatic alarm into one, and a system capable of automatic control in conjunction with related linkage equipment. Its basic forms include three types: the local alarm system, the centralized alarm system, and the control center alarm system.

Different buildings vary in their nature of use, degree of importance, fire hazard, structural form, fire resistance rating, distribution, environmental conditions, and difficulty of evacuation and firefighting. The installation of an automatic fire alarm system should be designed in a targeted manner according to the characteristics of the protected object and actual needs, so that the system is both suited to the protected object and capable of effectively achieving early alarm, while remaining economical and reasonable. The design of automatic fire alarm systems shall comply with the provisions of the national standard Code for Design of Automatic Fire Alarm System.

Different types of fire detectors differ in their response principles, structural characteristics, and applicable locations. In the design of a fire alarm system, the selection of the type of fire detector should be comprehensively determined based on the formation and development characteristics of the initial fire that may occur in the detection zone, the room height, environmental conditions, and possible causes of false alarms. For locations or parts where the initial fire has a smoldering stage, producing a large amount of smoke and a small amount of heat with little or no flame radiation, smoke detectors should be selected; for locations or parts where the fire develops rapidly and can produce a large amount of heat, smoke, and flame radiation, heat detectors, smoke detectors, flame detectors, or a combination thereof should be selected; for locations or parts where the fire develops rapidly, with intense flame radiation and a small amount of heat and smoke, flame detectors should be selected; for locations or parts where the fire formation characteristics are unpredictable, detectors may be selected based on the results of simulation tests. Due to technical requirements, the technical interlayer of a clean operating department is relatively high in height, has good airtightness, and contains a considerable amount of combustibles. Early detection and control of fire in this space is very important for preventing fire spread and ensuring personnel safety, especially the safety of people in spaces where operations are in progress. Fires in the technical interlayer of a clean operating department are dominated mainly by smoke in the early stage, so smoke detection devices should preferably be adopted.

Matters such as the selection of detector types, installation height and protection range, the design of fire alarm devices, the design and protection of fire alarm transmission lines, and the functions of the automatic alarm system are clearly specified in the national standard Code for Design of Automatic Fire Alarm System (GB50116-98). The fire protection design requirements concerning the location of the fire control room, fire separation, safe evacuation, resistance to electromagnetic interference, and communication may be implemented in accordance with the Code for Fire Protection Design of Buildings and the Code for Fire Protection Design of High-rise Civil Buildings (for the styles of detectors and fire alarm devices, see Figure 10.4).