In modern conditions of widespread electrification, not every fire can be extinguished with ordinary water. Some materials do not tolerate contact with liquids, so quenching with water causes them no less significant harm than fire.
Gas extinguishing systems are used in offices with expensive electrical equipment, museums, libraries, as well as on ships and aircraft.
Historical reference
For the first time , gas began to be used as a fire extinguishing agent in the second half of the 19th century. The first gas used for these purposes was carbon dioxide. Today, it is used in gas fire extinguishing systems only in archives and cash vaults. Freons became more widespread. For the first time in Russia, gas fire extinguishing was carried out in the 30s of the XX century.
Briefly about the equipment and its scope
Gas fire extinguishing is one of many fire fighting methods that use the following fire extinguishing agents: compressed gases (such as nitrogen and argon) and freons.
An automatic installation consists of the following elements: a container with gas, a pipeline with nozzles, a control panel, a central control unit, and detectors.
A key element of the system is a gas fire extinguishing module, structurally consisting of a container with gas and a starting device. As a rule, a gas cylinder can be refilled repeatedly after use. If the system is complex and consists of more than one module, they are combined with special devices - collectors.
The principle of the gas fire extinguishing system
Gas fire extinguishing is carried out according to the following principle: non-combustible gases are displaced into the ignition zone under the influence of high pressure, displacing oxygen from the air. As is known from the school chemistry course, in the absence of oxygen in the air, the combustion process slows down and ignition stops.
The rooms equipped with gas fire extinguishing systems are also equipped with special sensors that transmit information on the fire that has begun to the control panel. After the received signal, the control unit starts the fire extinguishing scenario: ventilation is blocked in the room, non-combustible gas is piped through the sprayers. The higher its concentration, the faster the fire will be put out. As a rule, gas fire extinguishing lasts less than one minute.
Automatic installations of gas fire extinguishing systems, their types
Automatic gas treatment facilities are usually used in non-residential premises where it is problematic to notice a fire without an automation system, as well as in warehouses with explosive and combustible substances. The main criterion for the classification of automatic fire extinguishing systems is mobility. On this basis, they are divided into mobile, portable and stationary.
In the first case, the equipment will be installed on the chassis or tracks; it can be both self-propelled and towed.
Fixed installations are located directly in the customer’s premises and are controlled by remote control.
Wearable are more common than others. These are fire extinguishers, the presence of which is mandatory for each room.
Mobility is not the only criterion for automatic installations. They are also classified by the method of control and supply of non-combustible substances, as well as by the total amount of extinguishing.
There are a great many ways to control a fire extinguishing installation, and besides, they can be combined with each other. That is, each manufacturer decides for himself how exactly this or that model of the automatic fire extinguishing installation will be controlled .
Non-combustible mixture can be supplied in two ways: modularly, using removable cylinders or centrally, from a common tank.
In terms of extinguishing, automatic gas extinguishing installations are local or complete extinguishing. In the first case, the substance is supplied only to the source of ignition (for example, gas fire extinguishing by the server can be organized only this way), in the second - along the entire perimeter of the room.
Design, calculation and installation of gas fire extinguishing systems
Installation of a gas fire extinguishing system requires careful observance of all applicable laws and full compliance with the requirements of each projected facility. Therefore, it is better to entrust such a complex and painstaking business to professionals.
When installing such a system, it is necessary to take into account many factors: the number and area of all rooms, room features (such as a suspended ceiling or false walls), general purpose, humidity characteristics, as well as ways to evacuate citizens in case of emergency.
In addition, there are some nuances in this matter. For example, when installing equipment in a room with high traffic, installation should be performed in such a way that, when the fire extinguishing system is activated, the oxygen concentration in the air remains within the limits allowed by the norms.
It is also necessary to remember that each gas fire extinguishing module must be protected from external factors.
Routine maintenance of gas fire extinguishing systems
In order for gas fire extinguishing installations to function properly during the entire period of operation, they need preventive maintenance from time to time. Every month, all components of the system should be checked for their tightness, and ignition sensors - for operability.
After each actuation of the fire extinguishing system, it is necessary to refuel the gas tanks and reconfigure the warning system.
All the listed preventive works are carried out directly at the customer’s site, that is, they do not require constant reinstallation of the system.
In addition, routine maintenance of the gas extinguishing system includes regular technical inspection of the modules. Each gas fire extinguishing module must be checked once every 10-12 years.
What is included in the installation work?
Before installing gas equipment, it is necessary to make sure that the manufacturer has state-certified certificates. It will not be superfluous to verify the license of the contracting company that carries out its installation.
Then, you definitely need to make sure that the ventilation systems are working, and only then start working.
All modules of the device are combined into a single system responsible for the operation of the device in case of fire, and control the situation in the room. At this stage, the owner must make sure that the design proposed by the master not only suits him aesthetically, but also does not interfere with the work of the staff.
After installing the system, the contractor draws up the acceptance certificate, which includes test reports and technical documentation for each of its elements.