Fire is a disaster capable to cause irreparable damage not only to property, but also directly to a human's life. There are a lot of reasons of ignition: careless electrical appliances handling, ignition of electrical wiring, unauthorized smoking and violation of fire safety rules. Every owner of real estate of any special purpose strives to improve the level of safety; therefore it is extremely necessary to install an automatic fire extinguishing system. Such systems efficiently and quickly react to the process of ignition of any scale, are able to localize or neutralize it without human intervention having previously warned by alarm about the start of the system’s operation. The automatic system performs tireless monitoring of the temperature regimen and smoke level using special indicators. In case of critical increase of values, the system comes into action, warns about the alarm, the signal goes directly to the fire control panel. Until the firefighters are on their way, the effective system localizes the fire by itself.
Automatic fire-extinguishing systems are classified in the following way:
- gas systems;
- aerosol systems;
- foam systems;
- dry-chemical systems;
- water systems;
- systems of water atomized spraying.
The first and the most common variant of systems is water fire extinguishing. Despite mass character of installation and its proven effectiveness, such systems have disadvantages: water can do damage to property in the process of extinguishing (archives, documentation) and installation of such systems is impossible wherein high-voltage electrical equipment is present. System of water atomized spraying is more delicate. Its main element is a special valve, which is affected by a temperature-sensitive locking device in the case of a fire. Most commonly such a device is a glass bulb, which bursts when the temperature rises. The valve is installed at the end of the water pipe. The main principle of work is to spray the smallest drops of water under ultra-high pressure; upon activation of such a system the premise is filled with a moist mist that displaces oxygen and localizes the fire seat.
According to the way of activation, the fire extinguishing systems are divided into sprinkler and drencher ones.
The main advantage of sprinkler fire extinguishing system is its operation only in direct proximity to the source of ignition. The reason is that the sprinkler systems include a heat-sensitive element that breaks down at a certain temperature thereby opening the valve. Another advantage of this system is a possibility of installing heat-sensitive elements with different thresholds of operating values.
Drencher systems come into action by fire alarm control and indicating equipment signal thus the fire extinguishing begins immediately after its detection. The disadvantage of such system is that extinguishing is carried out throughout the facility and not in the place of ignition. As a consequence, there is a large flow of water and additional damage caused by flooding of premises.
If an aerosol or powder is used in the premise during extinguishing, measures for preliminary evacuation of people are foreseen. Light and sound detector "powder. come out".
Automatic foam-extinguishing systems are relevant wherein combustible mixtures, liquids and substances are present since the foam has a smaller specific gravity and covers the entire surface neutralizing the flame. Such systems not to come cheap, require additional equipment (foam generator) but they work effectively.
Aerosol fire extinguishing systems appeared in the field of firefighting relatively recently, the acting basis of it is a fine powder (aerosol). They have a number of undeniable advantages: long service life, they do not provoke corrosion of metal and insulating structures, do not inflict harm to the human’s health and life and are non-toxic.
Dry-chemical extinguishing systems When a fire occurs, they throw out special powder fillers, the volumes of extinguishing can be local and large-scale. The powder may differ depending on the class of fire.
Gas systems of fire extinguishing are the most expensive option; they can be used in archives, museums, libraries and other premises where the use of water can do harm. The principle of operation of such a system is to reduce the concentration of oxygen by filling the fire zones with incombustible gas. The active substance is inert gases (argon, nitrogen, halocarbons), which allow a person to breathe during evacuation. The main rule is air tightness of the premise, which needs to be extinguished.
Criteria to choose an automatic fire-extinguishing system are simple: you need to determine the level of load, scales and volumes, the presence of electrical equipment, explosive substances and flammable liquids within the territory. Selection of the system should be well-grounded, carried out by specialists with experience and knowledge in safety engineering. Correctly selected fire extinguishing system is an opportunity to avoid serious consequences of fire, guarantee of safety of material values, property, but the most important - human life and health.
