Smoke and heat detectors
Smoke detectors
This type of detector detects fire by detecting smoke and by announcing it to the fire control system, they prepare the conditions for taking the necessary measures, and in general, these detectors are divided into three categories:
Photoelectric smoke detectors:
These detectors are made of a light source and a photoelectric sensor. When a fire occurs, the smoke from the fire enters the detector chamber and cuts off the light path, the light emitted from the light source does not reach the photoelectric sensor and therefore the system detects the fire.
Ionization Detectors:
A small amount of radioactive material is used in these detectors. In these detectors, there are two electrodes in the chamber, and there is an empty space between them. There is very little current between these two electrodes. When smoke enters this chamber, alpha rays are absorbed and reduce the ionization and current between the two electrodes. It is in this state that the detector announces the fire to the control system.
Beam Detectors:
These detectors include two modules that are installed in two different places and the radiation is sent from one module to the other module. In a normal state, the radiation sent is received by the receiver, but when a fire occurs and the resulting smoke is created, the path of the radiation is closed and the receiver will not receive it, and thus the occurrence of a fire is detected. These detectors are usually used for large areas that require many detectors.
Heat detectors
Unlike other detectors, heat detectors do not simply detect a fire. These detectors are sensitive to temperature changes and will act upon its sudden increase. These detectors are usually used in places that have a constant temperature, such as small rooms or kitchens. These detectors should not be used in places where the temperature is constantly fluctuating.
Conventional and Addressable equipment:
Each of the mentioned fire alarm detectors are available in two conventional and addressable types. In conventional systems, the components of the system do not have a specific address and different areas are determined as specific zones, which include several detectors or other equipment related to fire notification; At the end of each zone, a current limiting resistor (End Of Line) is placed. In addressable systems, each system component has a specific address and the equipment is connected to each other in a loop. In such systems, due to the addressability of the equipment, it is possible to accurately detect the location of the fire.
Also, an isolator system is usually considered for each equipment in order to remove it from the circuit when a problem occurs for the equipment in question and while notifying the control unit of the problem, to prevent any disruption in the operation of other equipment. Prevent.
