Fire fighting systems
Direct purpose of fire fighting systems - the prevention, restriction of development, fire extinguishing, people and property protection from fire.
The most reliable in solving the above problems are the automatic fire extinguishing system. In contrast to manual fire fighting systems and systems that are managed by the operator, these systems are driven automaticaly using the sensor readings. This provides a rapid quenching of the source of fire without human intervention.
Automatic fire fighting systems provide:
- twenty-four-hour control of temperature and the presence of smoke in the protected area;
- triggering of sound and light warning system;
- showing the signal "alarm" on the panel of fire service
- Automatic closing of fire-resistant valves and doors
- Automatic engaging of smoke removal systems
- Automatic feeding of extinguishing agent (EA)
- Notification about the EA feeding
As an extinguishing agent it’s used: an inert gas - Freon, carbon dioxide, foam (of low, medium, high multiplicity), fire extinguishing powders, aerosols and water.
Automatic fire extinguishing systems are classified by the extinguishing agent using:
- Gas (CO2, argon, nitrogen, and freons);
- Water-foam (water with foam formers);
- Powder (powder of a special chemical composition); Aerosol
"Water" settings are divided into sprinkler, intended for the local fire-fighting and drencher - to extinguish the fire in a large area. Sprinkler settings are programmed for triggering at a temperature rising above the set standards. While extinguishing the fire, the jet spray of water is served in close proximity to the source of fire. Governor assemblies of these settings are "dry" type - for unheated facilities, and "wet" type - for rooms, where the temperature does not drop below 0 degrees by C.
Sprinkler setttings are effective to protect the premises, fire in which, presumably, will grow rapidly.
Sprinklers of this type of settings are very diverse, it is possible to use them in rooms with different interior.
Drencher systems, in contrast to the sprinkler, are triggered by the command of fire detector. This allows to liquidate the fire of early development stage.
One of the novelties on the fire market – the setting with fine-air mist water supply system.
Tiny particles of water under high pressure have highly penetrating and smoke precipitating action. This system greatly enhances the fire extinguishing effect.
The notable disadvantage of all the above systems is the excessive water flow. Frequently, the damage, caused by the amount of supplied water is comparable with the fire consequences.
Sprinkler is a valve, triggered by the heat-sensitive locking device. Typically, it’s a glass capsule with fluid, which bursts at a given temperature. Sprinklers are installed on the pipelines, in which the water or air under high pressure are located inside.
As soon as the room temperature rises above the set one, the glass locking device of the sprinkler destroyes, due to the destruction, the water/air feeding valve is opened, pressure in the pipeline decreases. When the pressure is dropped, the sensor, which starts the water supply pump to the pipeline, is triggered. This option provides the delivery of the required amount of water to the site of a fire.
There are a number of sprinklers, which differ by different response temperature. "Perun” company offers a large selection of sprinklers, differing in response temperature, capacities, irrigation area and specificity, materials and finishes.
Regardless of the subspecies, sprinkler covers an area of 9 up to 21 m2
Wall sprinklers are designed to protect facilities, which architectural feature doesn’t allow placing a network of sprinkler pipelines under the ceiling or in the floor. These sprinklers are suitable for using in areas with a class of fire danger OH 1. Such sprinklers are designed for the locations with high temperature and corrosive environment.
Splinkers with preliminary action
Sprinklers with preliminary action significantly reduce the likelihood of false triggering. The structure of the device is such that both splinkers, which are a part of the system, have to be opened to enable the water supply.
The main difference of the drencher systems is that the water for fire extinguishing is fed directly into the pipeline in case of fire. At the time of fire these systems feed a much larger amount of water to the protected area. As a rule, drencher systems are used for creating a water curtain and cooling of particularly sensitive to heat and flammable objects.
For water supply to the dencher system it is used the, so-called, drencher control unit. The unit is activated by an electric, pneumatic or hydraulic means. The signal to start the drencher fire extinguishing system is served as automatically - fire alarm system, as manually.
Water mist fire extinguishing systems
Water mist fire extinguishing systems are designed and developed on the basis of the low pressure equipment. This provides a highly efficient fire protection with minimum outlet discharge and high reliability. Such systems are used for fires extinguishings of various classes. The extinguishing agent - water, as well as water with additives, gas-water mixture.
Water sprayed through a thin hole increases the area of impact, thus increasing the cooling effect, which then increases due to evaporation of water mist. This fire extinguishing method provides excellent effect of smoke particles thickening and the reflection of heat radiation.
Foam fire extinguishing
Allows to deal effectively with almost any type of fire. Foam extinguishing systems are able in a short period of time to suppress the fire by isolating the inflammable matter from the air.
This effect is achieved due to several factors:
1. Foam is lighter then any flammable liquids, because of this, it covers the surface, thereby suppressing the flame;
2. due to water contained in the foam former, inflamed material is cooled down to a temperature at which the reaction of combustion is not supported;
3. foam shroud prevents the release of combustible vapors that can mix with air.
Thus, foam generators are effective, ecologically clean means of fire extinguishing, which doesn’t pose a threat to human life and health. In addition, the big advantage of using them is that the foam from the generator itself is easily removed from the premises, without leaving a trace. Therefore, the use of foam generators lately got wide spread occurrence, especially in the chemical and petrochemical industry, working with flammable and combustible liquids.
Powder fire extinguishing systems
Are used in automatic powder fire extinguishing units. Used in extinguishing or localization of different fire classes (A, B, C - gaseous matter combustion), which is defined by the brand of used powder fire extinguishing.
Powder fire extinguishing unit is triggered, as by command fire alarm, as in an independent mode. A special powder is used as an extinguishing agent.
In the case of automatic triggering, the time of extinguishing agent feeding to the protected area does not exceed 35 seconds after sensor triggering. While an independent mode, the unit is usually throws out a one-time charge of powder. This option allows to extinguish the fire at an early stage in the narrowly focused area. For the automatic triggering, the system has to get the signal about the raising of the ambient temperature.
Extinguishing means: extensive, local – by area and volume.
Gas fire extinguishing systems
Represent cylinders with shut-off device for the storage and release of fire extinguishing gas mixtures. As the gas extinguishing agent, it is used the extinguishing matter, which is in gaseous state during extinguishing the flame. The start in this this module can be mechanical, electrical, pneumatic or represent their combination. Automatical gas fire extinguishing units are designed to create a protective environment. Fire extinguishing is carried out by filling the room with fire extinguishing gas mixture. It’s used the extensive or locally-volume method of quenching. The operating principle of the units is based on reducing the oxygen concentration due to the nonflammable gas entries into the reaction zone. Recently, such kind of systems got wide popularity. As an extinguishing agent, this unit uses an rare gas freon, as well as other rare gases, which create suitable environment for human breathing during the evacuation. The technological feature of gas quenching requires that the room, which needs to be extinguished, has to be hermetically sealed.
Gas fire extinguishing units can effectively extinguish a fire everywhere in the protected premises. Application of gas fire extinguishing systems, unlike water, powder, foam and spray, does not cause corrosion of the equipment being protected, and the consequences of its use easy to handle using conventional ventilation.
Gas fire extinguishing systems are recommended for the fire suppression of the electrical equipment under high voltage.
Aerosol fire-extinguishing systems
Presented systems use for fire extinguishing the fine-grained powder - spray. This substance has a high extinguishing capability. Aerosol fire extinguishing systems use the same principle of aerosol formation, based on the combustion of some solid chemical compositions. As a result of combustion of these substances a hot mixture of gases and particulates is produced, which fill the volume and extinguish the flame.
Systems of this kind are extremely easy to use and have several advantages over other systems.
1. Aerosol does not cause a devastating impact on the Earth's ozone layer.
2. Aerosol systems have a relatively low cost and long life.
3. Spray is not harmful for clothing and the human body.
4. The absence of a corrosive effect on the majority of structural and insulating materials.