Automatic fire detection devices, when combined with other elements of an emergency response and evacuation plan, can significantly reduce property damage, personal injuries, and loss of life because of fire accidents in the workplace. The main function of such devices is to identify a developing fire quickly and alert the building occupants and emergency response personnel before extensive damage takes place. Automatic fire detection systems achieve this by using electronic sensors to detect the smoke, heat, or flames from a fire and provide an early warning to the occupants.
How Do They Work?
Most fire detection systems that are in use have been designed and installed to meet the fire protection requirements of a specific OSHA standard, and they comply with the “Fire Detection Systems” standard 1910.164. These highly reliable fire detection devices have been a standard of the industry for over 45 years. In some systems, the fire detection device is used as an ALARM device, to sense overheat or fire, and alert personnel. In other systems, the fire detection units are used as a release device, to sense fire and actuate fire attack systems.
Types Of Fire Detectors
The three most common types of fire detectors are: smoke detectors, heat detectors and flame detectors.
The role of smoke detectors is to detect the visible or invisible smoke particles from combustion. The two main types of smoke detectors in use are ionization detectors and photoelectric detectors. The ionization detector contains a small radioactive source that is used to charge the air inside a small chamber. The charged air allows a small current to cross through the chamber and complete an electrical circuit. When smoke enters the chamber, it shields the radiation, which stops the current and triggers an alarm.
In the photoelectric smoke detector, a light source and light sensor are arranged in such a way that the rays from the light source do not hit the light sensor. When smoke particles enter the light path, some of the light is scattered and redirected onto the sensor, causing the detector to activate an alarm.
Heat detectors are used in dirty environments or places where dense smoke is produced. Heat detectors may be less sensitive when compared to smoke detectors, but are more appropriate than a smoke detector in these environments. The most common heat detectors either reacts to a broad temperature change or a predetermined fixed temperature.
Flame detectors are line-of-sight devices that look for specific types of light including infrared, visible, and ultraviolet, emitted by flames during combustion. When the detector recognizes this light from a fire, it sends a signal to activate an alarm.