Types of fire detectors. Review.
Fire detectors are a type of technical means designed to detect a fire, generate, collect, process, record and transmit in a given form signals about a fire, system operating modes, other information and, if necessary, issue signals to control technical means of fire protection, technological, electrical and other equipment.
The scientific classification of software implies that the types of fire detectors are represented by three varieties: traditional threshold, addressable threshold (non-polling and polling), — addressable-analog.
Fire detector types for addressable threshold systems use addressing at the level of individual SPS units.
They use widely used models of fire detectors without additional addressable elements; service areas are defined by one loop with an individual address in the system; operational reliability and stability of the system are increased due to the possibility of multiple backup of its functions.
These fire detector typesare easily and flexibly reconfigured.
The SPS is built by adding the necessary modification to the general structure of the equipment.
Addressable-analog systems are systems whose main difference is the separation of the functions of making decisions about an alarm.
Addressable-analog systems provide the ability to adjust the operation of the system as a whole depending on the characteristics of the object.
An addressable analog system collects and processes data on the state of an object and a system in real time.
These systems use detectors that are capable of providing information on the parameters that the detector monitors and on its current state.
These parameters are processed in the control panel, which makes the necessary decisions and implements the programmed algorithm for interaction with other components of the system, implementing the necessary control over the correctness of its execution using the principles of address identification. Let's consider the main types of PI addressable-analog systems.
Heat fire detector (IP)
The heat fire detector (IP) reacts to an increase in temperature in the protected area to 600-700C, depending on the modification.
Disposable sensors consist of two flexible plates connected by a special low-melting compound with a melting point of 700-720 C.
The reusable thermal fire detector (IP) consists of a reed switch surrounded by a magnet with two thin petal radiators.
At a temperature of 700 C, the magnetic field of the permanent magnet becomes insufficient (weakens) to keep the reed switch contacts in a closed state.
When selecting thermal fire detectors, it should be taken into account that the response temperature of maximum and maximum differential fire detectors should be at least 20°C higher than the maximum permissible air temperature in the room.
Thermal fire detector (FI) is used if significant heat emission is expected in the control zone in the event of a fire at its initial stage.
Differential and maximum differential thermal PI are used to detect a fire source if no sudden temperature changes unrelated to a fire are expected in the control zone, which could trigger the fire alarm of these subtypes.
Smoke fire alarm (DPI)
Smoke fire alarm (DPI) is an automatic optical-electronic device that responds to the appearance of smoke in a protected area. Manual action PI. are intended for forced manual issuance of a fire alarm during working hours.
The operating principle is based on breaking the loop by pressing a button or lever.
The DPI smoke fire alarm, powered by the SPS loop and having a built-in sounder, is recommended for use for prompt local notification and determination of the location of a fire in premises where the following conditions are met:
— the main factor in the occurrence of a fire in the initial stage is the appearance of smoke; — people may be present in the protected premises.
The DPI smoke fire alarm must be included in a single SPS with the output of alarm notifications to the PFKP located in the premises of the personnel on duty around the clock.
Flame fire alarm
Flame fire detector — a functional element of the fire safety system that detects the appearance of an open flame in a protected area and generates an alarm signal notifying of a fire.
Such detectors allow not only the fact of the appearance of a flame to be detected in a timely manner, but also to determine the source of the fire, which allows the flame to be quickly eliminated and the fire to be prevented from spreading.
Flame fire detectoris capable of protecting large outdoor areas, including those in hazardous areas.
The detector spends a minimum of time detecting the ignition of materials that do not have a smoldering stage, such as flammable liquids and plastics.
A flame fire detector has specific operating conditions, which are determined by the design features and placement of fire detectors.
The specifics of the use of flame fire detectors determines the weak coverage of this topic in the industry press, although there is a constant increase in interest in this equipment.
The spectral sensitivity of flame detectors must correspond to the radiation spectrum of the flame of combustible materials located in the FI control zone.
Flame FIs should be used to detect fires of those types of combustible substances and materials that are listed in the technical documentation for PI.