Fire Detectors Classification
Fire detectors are important components of fire detection and alarm systems: their function is to detect a fire at its initial stage. Using different types of fire detectors allows to optimize the fire alarm system for a specific building or room and provide reliable and unerring detection of fire.
According to EN 54-1 standard, a fire detector is a component of a fire detection and fire alarm system (FDAS) that contains at least one sensor which constantly or periodically monitors at least one suitable physical and/or chemical phenomenon associated with fire, and provides at least one corresponding signal to the control and indicating equipment. The decision to give the alarm of fire or to operate fire protection equipment or system may be made at the fire detector or at other FDAS component, for example the control panel (FACP).
Types of Fire Detectors
Classification of fire detectors can be based on different criteria.
For example, types of fire detectors according to monitored physical or chemical phenomenon:
- Smoke detectors are sensitive to particles of products of combustion and/or pyrolysis suspended in the air (aerosols).
- Heat detectors are sensitive to increase in air temperature.
- Flame detectors are sensitive to radiation emitted by flames from a fire.
- Combustion gas detectors are sensitive to gaseous products of combustion and/or thermal decomposition.
Multi-sensor detectors are designed to be sensitive to a wide range of fire types and reduce false alarms. They can compare the inputs from multiple sensors and monitor concurrently several phenomenon associated with fire.
In the standard, fire detectors are classified according to their configuration:
- Point type detectors, which respond to the phenomenon sensed in the proximity of a fixed point.
- Multipoint detectors, which respond to the phenomenon sensed in the proximity of few fixed points.
- Line type detectors, which respond to the phenomenon sensed in the proximity of a continuous line.
- Aspirating smoke detectors, in which air and aerosols are sucked through a sampling device and moved to one or more sensors by an integral aspirator (fan or pump).
In addition, fire detectors can be grouped in accordance with the method of their response to the monitored phenomenon (static, differential, rate of rise detectors), with their ability to return to their normal state of readiness (resettable, non-resettable detectors) or according to the possibility of the detector's head removal from its base (detachable, non detachable detectors).
Fire detectors are also categorized by the method of their initiation and taking decision to give the alarm:
- Manual call points can be used by personnel or residents to trigger an alarm in the event of a fire incident.
- Automatic fire detectors respond to environmental changes associated with fire and transfer signals to the fire alarm control panel.
- Self-contained (standalone) fire detectors are installed in locations where a full, wired fire alarm system is not needed. They perform the functions of fire detecting and produce alarm signals.
According to the type of connection and signal transmission, fire detectors are divided into categories:
- Hardwired, which are connected to the central control panel via physical wires.
- Wireless, which transmit signals through a radio bandwidth.
Criteria for Selection of Fire Detectors for the FDAS of a Building
Fire endangers property and human lives not only inside the building, but also on its premises. Fatal heat levels and toxic gases endanger the health of people and other living beings. That's why designing a fire alarm system and selection of its components requires a responsible approach.
When choosing fire detectors for a particular room or building, many things should be taken into account: technical parameters and operating conditions of the devices, characteristics of the room or the building, fire safety regulations and standards.
The main factors that determine the selection of fire detector type are:
a) the most probable type of fire at the initial stage and the predicted dynamics of its development (objects and materials in the monitored area, possible directions of fire spread),
b) room size (ceiling height is especially important),
c) availability of ventilation and heating systems,
d) microclimatic conditions in monitored space.
A single type of fire detectors that could quickly and accurately detect a fire in all possible conditions has not yet been invented. The choice of these components should be made based on analysis of specific conditions in the building. This may also lead to need to use a combination of fire detectors of different types.
In any case, the reliability of a fire alarm system depends on the quality of its components.
Our company develops and manufactures point addressable smoke and heat detectors. Our devices:
- have high sensitivity,
- ensure a minimum false alarm rate even in difficult operating conditions,
- operate reliably during service life specified by the manufacturer,
- have certificates of conformity.
Our specialists are ready to provide detailed consultations on technical parameters and technical application of fire detectors and other devices.