What is the extinguishing agent in gas fire extinguishing installations. The use of a fire extinguishing agent in gas fire extinguishing installations. Brief description of the protected object
Gas fire extinguishing has more than a century of history. The use of carbon dioxide (CO2) to extinguish fires was first started in the late 19th century in countries Western Europe and the United States, but widespread this method he received fire extinguishing only after the Second World War, when freons began to be used as the main component of GOS.
Basics and classification
At the moment, the regulatory documents in force in the Russian Federation allow the use of gas extinguishing compositions based on carbon dioxide, nitrogen, argon inergen, sulfur hexafluoride, as well as freon 227, freon 23, freon 125 and freon 218. According to the principle of operation, all GOS can be divided into two groups:
According to the storage method, fire extinguishing gas mixtures are divided into compressed and liquefied.
The field of application of gas fire extinguishing systems covers industries in which extinguishing with water or foam is undesirable, but contact of equipment or stored supplies with chemically aggressive powder mixtures- hardware rooms, server rooms, computing centers, ships and aircrafts, archives, libraries, museums, art galleries.
Most of the substances used for the production of waste water treatment plants are not toxic, however, the use of gas fire extinguishing systems creates an environment in an enclosed space that is unsuitable for life (this is especially true for waste water treatment plants from the group of deoxidants). Therefore, gas fire extinguishing systems pose a serious danger to human life. So on November 8, 2008, during the sea trials of the nuclear submarine "Nerpa", an unauthorized operation of the gas extinguishing system led to the death of more than twenty members of the submarine's crew.
In accordance with regulatory enactments, all automatic fire extinguishing systems with UWWTP as a working substance in mandatory should allow for the possibility of delaying the supply of the mixture until the complete evacuation of personnel. Rooms where automatic gas fire extinguishing is used are equipped with GAZ! DO NOT ENTER! " and "GAZ! LEAVE!" at the entrance to and exit from the premises, respectively.
Advantages and Disadvantages of Gas Fire Suppression
Fire extinguishing with the help of GOS is widespread due to a number of advantages, including:
- fire extinguishing with the help of GOS is carried out throughout the entire volume of the room;
- fire-extinguishing gas mixtures are non-toxic, chemically inert; when heated and in contact with burning surfaces, they do not disintegrate into poisonous and aggressive fractions;
- gas fire extinguishing practically does not harm equipment and material values;
- after the end of extinguishing, UWWTs are easily removed from the room by simple ventilation;
- application of GOS possesses high speed extinguishing a fire.
However, gas fire extinguishing also has some disadvantages:
- extinguishing a fire with gas requires sealing the room
- gas fire extinguishing is ineffective in large rooms or in open space.
- storage of loaded gas modules and maintenance of the fire extinguishing system is fraught with the difficulties associated with the storage of substances under pressure
- gas fire extinguishing installations are sensitive to temperature conditions
- GOS are unsuitable for extinguishing the fire of metals, as well as substances that can burn without oxygen.
Fire extinguishing installations using GOS
Gas fire extinguishing installations can be divided into three groups according to the degree of mobility:
V non-residential premises, in warehouses and storages, in enterprises related to the production and storage of fuels and explosive substances automatic gaseous fire extinguishing systems are widely used.
Diagram of an automatic gas fire extinguishing system
Since fire extinguishing with gas poses a high danger to the personnel of the enterprise, in the case of installing an automatic fire extinguishing system using the GOS at enterprises with a large number of employees, the integration of the automation of the system with the access control system (ACS) is required. In addition, the automatic fire extinguishing system should, upon a signal from the fire sensors, perform maximum sealing of the room in which the extinguishing is taking place - turn off ventilation, as well as close the automatic doors and lower the protective rollers, if any.
Automatic gas fire extinguishing systems are classified:
Equipping the facility with a gas fire extinguishing system
The initial calculation and planning of the installation of a gas fire extinguishing system begins with the choice of system parameters, depending on the specifics of a particular facility. The correct choice of extinguishing agent is of great importance.
Carbon dioxide (carbon dioxide) is one of the most inexpensive options State fire extinguishing system. Refers to fire-extinguishing substances-dioxidants, in addition, it has a cooling effect. Stored in a liquefied state, requires weight control of the leakage of the substance. Carbon dioxide-based mixtures are universal, limitation to use - fires with ignition of alkali metals.
Gas cylinders
Freon 23 is also stored in liquid form. Due to its high inherent pressure, no propellant gases are required. It is allowed to be used for extinguishing premises where people can stay. Environmentally friendly.
Nitrogen is an inert gas and is also used in fire extinguishing systems. It has a low cost, however, due to storage in a compressed form, the modules loaded with nitrogen are explosive. If the nitrogen gas extinguishing module does not work, it must be sprinkled abundantly with water from the shelter.
Steam fire extinguishing installations are of limited use. They are used in facilities that generate steam for their operation, for example, in power plants, ships with steam turbine engines, etc.
In addition, before designing, it is necessary to select the type gas installation fire extinguishing - centralized or modular. The choice depends on the size of the object, its architecture, number of storeys and number separate premises... Installation of a centralized type of fire extinguishing installation is advisable to protect three or more rooms within one facility, the distance between which does not exceed 100 m.
It should be taken into account that centralized systems are subject to a large number of requirements of the normative NPB 88-2001 - the main regulatory document governing the design, calculation and installation of fire-fighting installations. According to their design, gas fire extinguishing modules are divided into unitary modules - they include in their design one container with a compressed or liquefied gas mixture extinguishing and propellant gas; and batteries - several cylinders connected by a manifold. On the basis of the plan, a gas fire extinguishing project is being developed.
Designing a fire-fighting system using GOS
It is desirable that the entire range of works related to equipping the facility with a fire-prevention system (design, calculation, installation, commissioning, Maintenance) was carried out by one contractor. The design and calculation of the gas fire extinguishing system is carried out by the representative of the installer in accordance with NPB 88-2001 and GOST R 50968. The calculation of the installation parameters (the amount and type of fire extinguishing agent, centralization, the number of modules, etc.) is based on the following parameters:
- number of premises, their volume, availability false ceilings, false wall.
- area of permanently open openings.
- temperature, barometric and hygrometric (air humidity) conditions at the facility.
- availability and work mode of personnel (routes and time of personnel evacuation in case of fire).
When calculating the estimate for the installation of fire extinguishing system equipment, some specific aspects should be taken into account. For example, the cost of one kilogram of fire-extinguishing gas mixture is higher when using modules with compressed gas, since each such module contains a smaller mass of substance than a module with liquefied gas therefore, the latter will be required less.
The cost of installing and maintaining a centralized extinguishing system is usually less, however, if the facility has several sufficiently remote rooms, the savings are "eaten away" by the cost of pipelines.
Installation and maintenance of a gas fire extinguishing station
Before the start installation works When assembling a gas fire extinguishing installation, it is necessary to make sure that there are certificates for the equipment subject to mandatory certification and check that the installer has a license to work with gas, pneumatic and hydraulic equipment.
The room, equipped with a gas fire extinguishing station, must be equipped with exhaust ventilation to remove air. The air removal rate is equal to three for freons and six for deoxidants.
The manufacturer carries out the installation of fire extinguishing modules or centralized balloon tanks, trunk and distribution pipelines and starting systems. The modular or centralized pipeline part of the gas extinguishing station is integrated into a single automated control and monitoring system.
Piping and system elements automated control should not interfere with the appearance and functionality of the premises. Upon completion of installation and adjustment, an act of completed work is drawn up, and an act of acceptance and transfer to which test reports and technical passports of the equipment used are attached. A maintenance contract is signed.
Equipment performance tests are repeated at least once every five years. Maintenance of gas extinguishing systems includes:
- regular testing of the efficiency of the elements of the gas extinguishing station;
- routine maintenance and Maintenance equipment;
- weight testing of modules for the absence of UWTF leakage.
Despite certain difficulties associated with installation and use, gas systems fire extinguishing have a number of undoubted advantages and high efficiency in its field of application.
The design of gas fire extinguishing systems is a rather complex intellectual process, the result of which is a workable system that reliably, timely and effectively protects an object from fire. This article discusses and analyzesproblems arising in the design of automaticgas fire extinguishing installations. Possibilityof these systems and their effectiveness, as well as considerationrush possible options optimal constructionautomatic gas fire extinguishing systems. Analysisof these systems is made in full compliance with the requirementsrequirements of the set of rules SP 5.13130.2009 and other norms, actcurrent SNiP, NPB, GOST and Federal laws and ordersRF on automatic fire extinguishing installations.
Chief Engineer project of OOO ASPT Spetsavtomatika
V.P. Sokolov
Today, one of the most effective means extinguishing fires in rooms to be protected by automatic fire extinguishing installations AUPT in accordance with the requirements of SP 5.13130.2009 Appendix "A" are automatic gas fire extinguishing installations. Type of automatic installation extinguishing, the method of extinguishing, the type of fire extinguishing means, the type of equipment for the fire-fighting automation installations are determined by the design organization depending on the technological, structural and space-planning features of the protected buildings and premises, taking into account the requirements of this list (see clause A.3.).
The use of systems where a fire extinguishing agent in case of fire is automatically or remotely in a manual start-up mode is supplied to the protected room is especially justified when protecting expensive equipment, archival materials or valuables. Installations automatic fire extinguishing allow to eliminate at an early stage the ignition of solid, liquid and gaseous substances, as well as electrical equipment under voltage. This method of extinguishing can be volumetric - when creating a fire extinguishing concentration throughout the entire volume of the protected room or local - in the event that a fire extinguishing concentration is created around the protected device (for example, a separate unit or unit technological equipment).
When choosing the optimal control option for automatic fire extinguishing installations and choosing a fire extinguishing agent, as a rule, they are guided by the norms, technical requirements, features and functionality of the protected objects. When properly selected, gaseous fire extinguishing agents practically do not cause damage to the protected object, the equipment located in it with any production and technical purpose, as well as the health of the personnel working in the protected premises with a constant presence. The unique ability of gas to penetrate through cracks into the most inaccessible places and effectively act on the source of fire is widely used in the use of gas extinguishing agents in automatic gas fire extinguishing installations in all areas of human activity.
That is why automatic gas fire extinguishing installations are used to protect: data processing centers (DPC), server rooms, telephone communication centers, archives, libraries, museum stores, bank cash vaults, etc.
Consider the types of fire extinguishing agents most commonly used in automatic gas fire extinguishing systems:
Freon 125 (C 2 F 5 H) standard volumetric fire extinguishing concentration according to N-heptane GOST 25823 is - 9.8% of the volume (brand name HFC-125);
Freon 227ea (C3F7H) standard volumetric fire extinguishing concentration according to N-heptane GOST 25823 is equal to - 7.2% of the volume (brand name FM-200);
Freon 318C (C 4 F 8) standard volumetric fire extinguishing concentration according to N-heptane GOST 25823 is equal to - 7.8% of the volume (brand name HFC-318C);
Freon FK-5-1-12 (CF 3 CF 2 C (O) CF (CF 3) 2) standard volumetric fire extinguishing concentration according to N-heptane GOST 25823 is equal to - 4.2% of the volume (brand name Novec 1230);
Carbon dioxide (CO 2) normative volumetric fire extinguishing concentration according to N-heptane GOST 25823 is equal to - 34.9% of the volume (can be used without constant stay of people in the protected area).
We will not analyze the properties of gases and their principles of impact on a fire in a fire. Our task will be the practical use of these gases in automatic gas fire extinguishing installations, the ideology of building these systems in the design process, the issues of calculating the mass of gas to ensure the normative concentration in the volume of the protected room and determining the diameters of the pipes of the supply and distribution pipelines, as well as the calculation of the area of the outlet openings of the nozzle ...
In gas fire extinguishing projects, when filling out the drawing stamp, on the title pages and in the explanatory note, we use the term automatic gas fire extinguishing installation. Actually this term it is not entirely correct and it would be more correct to use the term automated gas fire extinguishing installation.
Why is that! See the list of terms in SP 5.13130.2009.
3. Terms and definitions.
3.1 Automatic start of the fire extinguishing installation: starting the installation from its technical means without human intervention.
3.2 Automatic fire extinguishing installation (AUP): fire extinguishing installation, automatically triggered when the controlled factor (s) of the fire exceed the set threshold values in the protected area.
In the theory of automatic control and regulation, there is a division of the terms automatic control and automated control.
Automatic systems is a complex of software and hardware and devices working without human intervention. An automatic system does not have to be a complex set of devices to control engineering systems and technological processes... It can be one automatic device that performs predetermined functions according to a predetermined program without human intervention.
Automated systems Is a complex of devices that convert information into signals and transmit these signals over a distance over a communication channel for measurement, signaling and control without human intervention or with his participation on no more than one side of the transmission. Automated systems are a combination of two automatic control systems and a manual (remote) control system.
Consider the composition of automatic and automated control systems for active fire protection:
Means for obtaining information - data collection devices.
Means for transmitting information communication lines (channels).
Means for receiving, processing information and issuing control signals of the lower level - local receptions electrical devices,instruments and stations for monitoring and control.
Means for using information- automatic regulators andactuators and warning devices for various purposes.
Means for displaying and processing information, as well as automated control of the upper level - central control panel orautomated workplace operator.
Automatic installation of gas fire extinguishing AUGPT includes three starting modes:
- automatic (starting from automatic fire detectors);
- remote (starting is carried out from a manual fire detector located at the door to the protected area or from a security post);
- local (from a mechanical device for manual start located on the launch module "cylinder" with a fire extinguishing agent or next to the fire extinguishing module for liquid carbon dioxide MPZhU, which is structurally made in the form of an isothermal container).
Remote and local starting will only be performed with human intervention. So the correct decoding of AUGPT will be the term « Automated installation of gas fire extinguishing ".
V recent times The customer, when agreeing and approving a gas fire extinguishing project for work, requires that the inertia of the fire extinguishing installation be indicated, and not just the estimated delay time for the release of gas to evacuate personnel from the protected area.
3.34 The inertia of the fire extinguishing installation: the time from the moment the controlled fire factor reaches the threshold of the sensitive element of the fire detector, sprinkler sprinkler or incentive device to the beginning of the supply of fire extinguishing agent into the protected area.
Note- For fire extinguishing installations, in which a time delay is provided for the release of fire extinguishing agent in order to safely evacuate people from the protected room and (or) to control technological equipment, this time is included in the inertia of the AUP.
8.7 Time characteristics (see SP 5.13130.2009).
8.7.1 The installation should delay the release of GFW into the protected room during automatic and remote start-up for the time required to evacuate people from the room, turn off ventilation (air conditioning, etc.), close the dampers (fire dampers, etc.), but not less than 10 sec. from the moment the evacuation warning devices are turned on in the room.
8.7.2 The installation should ensure inertia (response time without taking into account the delay time for the release of the GFFS) no more than 15 seconds.
The delay time for the release of a gaseous fire extinguishing agent (GFFS) into the protected room is set by programming the operation algorithm of the station that controls the gaseous fire extinguishing. The time required to evacuate people from the premises is determined by calculation using a special method. The time interval of delays for the evacuation of people from the protected premises can be from 10 sec. up to 1 min. and more. The gas release delay time depends on the dimensions of the protected room, on the complexity of technological processes in it, functional features installed equipment and technical purpose, both individual premises and industrial facilities.
The second part of the inertial delay of the gas fire extinguishing installation in time is the product of the hydraulic calculation of the supply and distribution pipeline with nozzles. The longer and more complex the main pipeline to the nozzle, the greater importance has the inertia of the gas fire extinguishing installation. In fact, compared to the time delay required to evacuate people from the protected premises, this value is not so large.
The inertia time of the installation (the beginning of the gas flow through the first nozzle after opening the shut-off valves) is, min 0.14 sec. and max. 1.2 sec. This result was obtained from the analysis of about a hundred hydraulic calculations of varying complexity and with different gas compositions, both freons and carbon dioxide contained in cylinders (modules).
Thus, the term "Inertia of the gas fire extinguishing installation" consists of two components:
Gas release delay time for safe evacuation of people from the premises;
The time of the technological inertia of the installation itself during the release of GFFS.
It is necessary to separately consider the inertia of a gas fire extinguishing installation with carbon dioxide based on a tank of an isothermal firefighting unit "Volcano" with different volumes of the used vessel. A structurally unified series is formed by vessels with a capacity of 3; 5; ten; 16; 25; 28; 30m3 for a working pressure of 2.2MPa and 3.3MPa. To complete these vessels with shut-off and starting devices (ZPU), depending on the volume, three types of shut-off valves are used with nominal diameters of the outlet opening 100, 150 and 200 mm. A ball valve or a butterfly valve is used as an actuating mechanism in the shut-off and starting device. A pneumatic actuator with a working pressure on the piston of 8-10 atmospheres is used as a drive.
Unlike modular installations, where the electric start of the head shut-off-starting device is carried out almost instantly, even with the subsequent pneumatic start of the remaining modules in the battery (see Fig-1), the butterfly valve or ball valve opens and closes with a slight delay in time, which can be 1-3 sec. depending on the equipment produced by the manufacturer. In addition, the opening and closing of this ZPU equipment in time, due to the design features of the stop valves, has a far from linear relationship (see Fig-2).
The figure (Fig-1 and Fig-2) shows a graph on which one axis is the mean carbon dioxide consumption, and the other axis is the time value. The area under the curve within the target time determines the calculated amount of carbon dioxide.
Average consumption of carbon dioxide Q m, kg / s, is determined by the formula
where: m- the estimated amount of carbon dioxide ("Mg" according to SP 5.13130.2009), kg;
t- standard time of supply of carbon dioxide, s.
with carbon dioxide of modular type. 
Fig-1.
1-
to - opening time of the locking and starting device (ZPU).
tx – the time of the end of the flow of CO2 gas through the ZPU.
Automated installation of gas fire extinguishing
with carbon dioxide on the basis of the isothermal tank MPZHU "Volcano".
Fig-2.
1- curve that determines the consumption of carbon dioxide over time through the ZPU.
The storage of the main and reserve stock of carbon dioxide in isothermal containers can be carried out in two different separately standing tanks or together in one. In the second case, it becomes necessary to close the locking and starting device after the main stock leaves the isothermal container during an emergency situation of extinguishing a fire in the protected room. This process is shown as an example in the figure (see Fig-2).
The use of an isothermal tank MPZHU "Vulkan" as a centralized fire extinguishing station in several directions, implies the use of a locking and starting device (ZPU) with an open-close function to cut off the required (calculated) amount of extinguishing agent for each direction of gas fire extinguishing.
The presence of a large distribution network of the gas fire extinguishing pipeline does not mean that the gas outflow from the nozzle will not start before the ZPU fully opens, therefore, the opening time of the exhaust valve cannot be included in the technological inertia of the installation when the GFFS is released.
A large number of automated gas fire extinguishing installations are used at enterprises with different technical production for the protection of process equipment and installations, both with normal operating temperatures and with a high level of operating temperatures on the working surfaces of the units, for example:
Gas pumping units of compressor stations, subdivided by type
drive engine for gas turbine, gas engine and electric;
High pressure compressor stations driven by an electric motor;
Generating sets with gas turbine, gas engine and diesel
drives;
Production technological equipment for compression and
preparation of gas and condensate at oil and gas condensate fields, etc.
Let's say working surface In certain situations, gas turbine drive casings for an electric generator can reach sufficiently high heating temperatures, exceeding the autoignition temperature of some substances. In the event of an emergency, a fire, on this technological equipment and the further elimination of this fire using an automatic gas fire extinguishing system, there is always the possibility of a relapse, re-ignition when hot surfaces come into contact with natural gas or turbine oil, which is used in lubrication systems.
For equipment with hot work surfaces in 1986. VNIIPO of the Ministry of Internal Affairs of the USSR for the Ministry of Gas Industry of the USSR developed a document "Fire protection of gas-pumping units of compressor stations of main gas pipelines" (Generalized recommendations). Where it is proposed to use individual and combined fire extinguishing installations for extinguishing such objects. Combined fire extinguishing installations involve two stages of putting fire extinguishing agents into action. The list of combinations of fire extinguishing agents is available in the generalized manual. In this article, we only consider combined gas fire extinguishing installations "gas plus gas". The first stage of gas fire extinguishing of the facility complies with the norms and requirements of SP 5.13130.2009, and the second stage (extinguishing) eliminates the possibility of re-ignition. The method for calculating the mass of gas for the second stage is given in detail in the generalized recommendations, see the section "Automatic gas fire extinguishing installations".
To start up the first stage gas fire extinguishing system in technical installations without the presence of people, the inertia of the gas fire extinguishing installation (delay in starting the gas) must correspond to the time required to stop the operation of technical means and turn off the equipment air cooling... The delay is intended to prevent the entrainment of the gas extinguishing agent.
For a second stage gas fire extinguishing system, a passive method is recommended to prevent recurrence of re-ignition. The passive method involves inerting the protected area for a time sufficient for the natural cooling of the heated equipment. The time for supplying the extinguishing agent to the protected area is calculated and, depending on the technological equipment, can be 15-20 minutes or more. The operation of the second stage of the gas fire extinguishing system is carried out in the mode of maintaining a given fire extinguishing concentration. The second stage of gas fire extinguishing is switched on immediately after the end of the first stage. The first and second stages of gas fire extinguishing for the supply of a fire extinguishing agent must have their own separate piping and a separate hydraulic calculation of the distribution pipeline with nozzles. The time intervals between which the cylinders of the second stage of fire extinguishing are opened and the supply of fire extinguishing agent is determined by calculations.
As a rule, carbon dioxide CO 2 is used to extinguish the equipment described above, but freons 125, 227ea and others can also be used. Everything is determined by the value of the protected equipment, the requirements for the effect of the selected extinguishing agent (gas) on the equipment, as well as the extinguishing efficiency. This issue lies entirely in the competence of specialists involved in the design of gas fire extinguishing systems in this area.
The control scheme of the automation of such an automated combined gas fire extinguishing installation is rather complicated and requires a very flexible logic of control and management from the control station. It is necessary to carefully approach the choice of electrical equipment, that is, to control devices for gas fire extinguishing.
Now we need to consider general issues for the placement and installation of gas fire extinguishing equipment.
8.9 Pipelines (see SP 5.13130.2009).
8.9.8 The distribution piping system, as a rule, should be symmetrical.
8.9.9 The internal volume of pipelines should not exceed 80% of the volume of the liquid phase of the calculated amount of GFFS at a temperature of 20 ° C.
8.11 Nozzles (see SP 5.13130.2009).
8.11.2 The nozzles should be located in the protected room, taking into account its geometry and ensure the distribution of GFFS throughout the volume of the room with a concentration not lower than the standard.
8.11.4 The difference in the GFFS flow rates between the two extreme nozzles on the same distribution pipeline should not exceed 20%.
8.11.6 In one room (protected volume), nozzles of only one standard size must be used.
3. Terms and definitions (see SP 5.13130.2009).
3.78 Distribution pipeline: pipeline on which sprinklers, sprayers or nozzles are mounted.
3.11 Branch of the distribution pipeline: section of a row of a distribution pipeline located on one side of the supply pipeline.
3.87 Distribution pipe row: a set of two branches of the distribution pipeline, located along the same line on both sides of the supply pipeline.
Increasingly, when approving project documentation for gas fire extinguishing, one has to deal with different interpretations some terms and definitions. Especially if the axonometric layout of pipelines for hydraulic calculations is sent by the Customer himself. In many organizations, the same specialists are engaged in gaseous fire extinguishing systems and water fire extinguishing systems. Consider two layouts of gas fire extinguishing pipes, see Fig-3 and Fig-4. The comb-type scheme is mainly used in water-based fire extinguishing systems. Both schemes shown in the figures are also used in the gas fire extinguishing system. There is only a limitation for the comb-type scheme; it can only be used for extinguishing with carbon dioxide (carbon dioxide). The standard time for the release of carbon dioxide into the protected room is no more than 60 seconds, and it does not matter if it is a modular or centralized gas fire extinguishing installation.
The time for filling the entire pipeline with carbon dioxide, depending on its length and tube diameters, can be 2-4 seconds, and then the entire pipeline system to the distribution pipelines, on which the nozzles are located, turns, as in the system, of water fire extinguishing into a “supply pipeline”. Subject to all the rules of hydraulic calculation and the correct selection of the internal diameters of the pipes, the requirement will be fulfilled, in which the difference in the GFW flow rate between the two extreme nozzles on one distribution pipeline or between the two extreme nozzles on the two extreme rows of the supply pipeline, for example, rows 1 and 4, will not exceed twenty%. (see copy of clause 8.11.4). The working pressure of carbon dioxide at the outlet in front of the nozzles will be approximately the same, which will ensure a uniform consumption of the GFFS fire extinguishing agent through all nozzles in time and the creation of a standard gas concentration at any point in the volume of the protected room after 60 seconds. since the start of the gas fire extinguishing installation.
Another thing is a kind of fire extinguishing agent - freons. The standard time for the release of freon into the protected room for modular fire extinguishing is no more than 10 sec., And for a centralized installation no more than 15 sec. etc. (see SP 5.13130.2009).
fire extinguishingaccording to the “comb” type scheme.
FIG-3.
As the hydraulic calculation with freon gas (125, 227ea, 318Ts and FK-5-1-12) shows, for the axonometric layout of the “comb” type pipeline, the main requirement of the set of rules is to ensure a uniform flow of fire extinguishing agent through all nozzles and to ensure the distribution of GFFS over the entire volume of the protected premises with a concentration not lower than the standard (see copy of clause 8.11.2 and clause 8.11.4). The difference in consumption of GFFS of the freon family through the nozzles between the first and the last rows can reach 65% in the place of the permissible 20%, especially if the number of rows on the supply pipeline reaches 7 pcs. and more. Obtaining such results for a gas of the freon family can be explained by the physics of the process: the transience of the process in time, the fact that each subsequent row takes a part of the gas onto itself, a gradual increase in the length of the pipeline from row to row, the dynamics of resistance to gas movement through the pipeline. This means that the first row with nozzles on the supply pipeline is more favorable conditions work than the last row.
The rule states that the difference in the flow rate of the GFFS between the two extreme nozzles on the same distribution pipeline should not exceed 20% and nothing is said about the difference in flow rate between the rows on the supply pipeline. Although another rule states that the nozzles should be placed in the protected room, taking into account its geometry and ensure the distribution of GFFS throughout the volume of the room with a concentration not lower than the standard.
Gas installation pipeline layout plan
fire extinguishing according to a symmetrical scheme.
FIG-4.
How to understand the requirement of the code of practice, the distribution piping system, as a rule, should be symmetrical (see copy 8.9.8). The comb-type piping system of the gas fire extinguishing installation also has symmetry with respect to the supply pipeline and, at the same time, does not provide the same flow rate of freon gas through the nozzles throughout the entire volume of the protected room.
Fig-4 shows the piping system for installing gas fire extinguishing in accordance with all the rules of symmetry. This is determined by three criteria: the distance from the gas module to any nozzle has the same length, the diameters of the pipes to any nozzle are identical, the number of bends and their direction are the same. The difference in gas flow rates between any nozzles is practically zero. If, according to the architecture of the protected premises, it is necessary to lengthen or move some kind of distribution pipeline with a nozzle, the difference in flow rates between all nozzles will never go beyond 20%.
Another problem for gas fire extinguishing installations is the high heights of the protected premises from 5 m and more (see Fig-5).
Axonometric diagram of the pipeline layout of the gas fire extinguishing installationin a room of the same volume with a high ceiling height.
Fig-5.
This problem arises when protecting industrial enterprises, where the production workshops to be protected can have ceilings up to 12 meters high, specialized archive buildings with ceilings reaching heights of 8 meters and above, hangars for storing and servicing various special equipment, gas and oil products pumping stations, etc. .d. Common maximum height installation of a nozzle relative to the floor in a protected room, widely used in gas fire extinguishing installations, as a rule, is no more than 4.5 meters. It is at this height that the developer of this equipment checks the operation of his nozzle for compliance with its parameters with the requirements of SP 5.13130.2009, as well as the requirements of other regulatory documents of the Russian Federation on fire safety.
At high altitude industrial premises, for example 8.5 meters, the process equipment itself will definitely be located at the bottom of the production site. In case of volumetric extinguishing with a gas fire extinguishing installation in accordance with the rules of SP 5.13130.2009, the nozzles must be located on the ceiling of the protected room, at a height of no more than 0.5 meters from the ceiling surface in strict accordance with their technical parameters. It is clear that the height of the production room 8.5 meters does not correspond to technical specifications nozzle. The nozzles should be located in the protected room, taking into account its geometry and ensure the distribution of GFFS throughout the volume of the room with a concentration not lower than the standard (see copy of clause 8.11.2 from SP 5.13130.2009). The question is how long in time the normative gas concentration will equalize over the entire volume of the protected premises with high ceilings, and what rules can regulate this. One solution seems to be this issue this is a conditional division of the total volume of the protected room by height into two (three) equal parts, and along the boundaries of these volumes, symmetrically install additional nozzles every 4 meters down the wall (see Fig-5). The additionally installed nozzles allow faster filling of the volume of the protected room with a fire-extinguishing agent while ensuring the standard gas concentration, and, more importantly, provide a quick supply of the fire-extinguishing agent to the technological equipment at the production site.
It is most convenient for the given pipe routing scheme (see Fig-5) to have nozzles with spraying of GFFS at 360 ° on the ceiling, and on the walls of the nozzles with side spraying of GFFS at 180 ° of one standard size and equal estimated area of holes for spraying. As the rule states, in one room (protected volume), nozzles of only one standard size should be used (see copy of clause 8.11.6). True, the definition of the term for a nozzle of one standard size in SP 5.13130.2009 is not given.
For the hydraulic calculation of the distribution pipe with nozzles and the calculation of the mass the required amount gas extinguishing agent to create a standard fire extinguishing concentration in the protected area, modern computer programs are used. Previously, this calculation was carried out manually using special approved methods. This was a difficult and time-consuming operation, and the result obtained had a rather large error. To obtain reliable results of hydraulic calculation of pipe routing, a great experience of a person involved in calculating gas fire extinguishing systems was required. With the advent of computer and training programs, hydraulic calculations have become available to a large circle of specialists working in this field. Computer program "Vector", one of the few programs that allows you to optimally solve all kinds of complex problems in the field of gaseous fire extinguishing systems with minimal loss of time for calculations. To confirm the reliability of the calculation results, the hydraulic calculations were verified according to computer program"Vector" and received a positive Expert opinion No. 40 / 20-2016 from 03/31/2016. The State Fire Service Academy of the Russian Emergencies Ministry for the use of the Vector hydraulic calculation program in gas fire extinguishing installations with the following extinguishing agents: Khladon 125, Khladon 227ea, Khladon 318Ts, FK-5-1-12 and CO2 (carbon dioxide) produced by ASPT Spetsavtomatika LLC.
The computer program of hydraulic calculations "Vector" frees the designer from routine work. It contains all the rules and regulations of SP 5.13130.2009, it is within the framework of these restrictions that calculations are performed. A person inserts into the program only his initial data for the calculation and makes changes if he is not satisfied with the result.
Finally I want to say that we are proud that, according to many experts, one of the leading Russian manufacturers automatic gas fire extinguishing installations in the field of technology is ASPT Spetsavtomatika LLC.
The company's designers have developed whole line modular installations for different conditions, features and functionality of protected objects. The equipment fully complies with all Russian regulatory documents. We carefully follow and study the world experience in development in our field, which allows us to use the most advanced technologies in the development of our own production plants.
An important advantage is that our company not only designs and installs fire extinguishing systems, but also has its own production base for the manufacture of all necessary equipment for fire extinguishing - from modules to manifolds, pipelines and nozzles for gas spraying. Our own gas filling station gives us the opportunity to as soon as possible to refuel and inspect a large number of modules, as well as to carry out comprehensive tests of all newly developed gas fire extinguishing systems (GFG).
Cooperation with the world's leading manufacturers of fire extinguishing compositions and manufacturers of GFFS within Russia allows ASPT Spetsavtomatika LLC to create multi-profile fire extinguishing systems using the safest, most efficient and widespread compositions (Freon 125, 227ea, 318Ts, FK-5-1-12, carbon dioxide ( CO 2)).
LLC "ASPT Spetsavtomatika" offers not one product, but a single complex - a full set of equipment and materials, design, installation, commissioning and subsequent maintenance of the above-listed fire extinguishing systems. Our organization regularly holds free training in design, installation and commissioning of manufactured equipment, where you can get the most complete answers to all your questions, as well as get any advice in the field of fire protection.
Reliability and high quality Is our top priority!
The gas fire extinguishing system is an extremely effective installation for prompt fire extinguishing at the initial stage of ignition. Its special value is the absence of additional damage by the fire extinguishing agent to the protected equipment, stored documents, and artistic values.
The inevitable effect of water, chemical foam, powders on building construction, interior decoration, furniture, office, household appliances, documentation in the course of extinguishing a fire often leads to direct and indirect material losses, quite comparable to the applied fire, combustion products.
Filling the volume of the room with a mixture of inert gases that do not interact with burning materials quickly reduces the oxygen content (less than 12%), making the combustion process impossible. In gas fire extinguishing systems, the following are used:
- liquefied gases - freons (carbon - fluoride compounds used as refrigerants), sulfur hexafluoride (SF6), carbon dioxide (CO2);
- compressed gases - nitrogen, argon, argonite (50% nitrogen + 50% argon), inergen (52% nitrogen + 40% argon + 8% CO2).
The gases used, their mixtures up to certain concentrations (!) In the air are not hazardous to human health, and also do not deplete the ozone layer.
An automatic gas fire extinguishing system (ASGP) is a set of vessels for storing liquefied, compressed fire extinguishing substances, supply pipelines with nozzles, incentive (signal-triggering) devices, and a control unit. There are several ways to enable LRA:
- auto;
- remote;
- local.
The last two types are redundant, auxiliary methods that ensure the start of the fire extinguishing system in case of malfunctions of the automatic fire alarm system. They are used by manually trained personnel of the enterprise, security personnel from the premises of the fire extinguishing station of the centralized gas fire extinguishing system or from the system triggering device installed in front of the entrance to the premises.
By the type of object protection, the automatic gas fire extinguishing system is distinguished:
Volumetric fire extinguishing systems.
They are used for prompt filling of a room or a group of premises of a building with a gas mixture, where expensive technological, electrical equipment, material, artistic values are located.
Local fire extinguishing systems.
They are used to extinguish the source of a fire on separate technological equipment, if extinguishing the entire volume of the room is impossible.
The need to use an automatic fire extinguishing system, its type, type of extinguishing gas for various buildings, premises, equipment is determined by the current state regulations and rules in the field of fire protection.
INSTALLATION AND INSTALLATION OF GAS FIRE EXTINGUISHING SYSTEM
To determine the need for the design of an automatic fire extinguishing system, the development of documentation, there are two main documents in this area of fire regulation: NPB 110-03, SP 5.13130.2009, which regulate all issues of design, installation of automatic fire extinguishing installations.
In addition, for the calculation, design, installation, installation of a gas fire extinguishing system, the following official documents are used:
Fire safety standards,
Federal standards (GOST R), which determine the composition, installation methods, installations, test methods and timing, check the performance of the gas mixture fire extinguishing system at the end of installation and commissioning work.
There are also sectoral, departmental norms for the device of the ASGP, which take into account the specifics of objects, the properties of the substances used, materials.
According to clause 3 of NPB 110-03, the type of automatic installation, the choice of extinguishing agent, type, method of fire extinguishing, the type of equipment used is determined by the design organization based on the construction, design and technological parameters of the protected objects. As a rule, they design gas fire extinguishing systems, install, assemble standard solutions of ASGP stations on the following categories of objects to be protected:
Buildings of federal, regional, special archives, where rare editions, various reports, documentation of particular value are kept.
Maintenance-free technical workshops of radio centers, radio relay stations.
Unattended premises of hardware complexes of cellular base stations.
Auto halls of automatic telephone exchange with switching equipment, premises electronic stations, nodes, centers, the number of rooms, channels 10 thousand and more.
Premises for storage, issuance of rare publications, manuscripts, important reporting documents in public, administrative buildings.
Depositories, storerooms of museums, exhibition complexes, art galleries of federal and regional significance.
Premises of computer complexes used in the control of technological processes, the shutdown of which will affect the safety of personnel, environmental pollution.
Server, archives of various media.
The last point also applies to modern data centers, data centers with expensive equipment.
The primary data for the development of the project, calculations, further installation, installation of automatic fire extinguishing are: the list of protected premises, the presence of spaces for suspended ceilings, technical pits (raised floors), geometry, volume of premises, dimensions of enclosing structures, parameters of technological and electrical equipment.
Centralized ASGP is called a system containing cylinders with UWWT, installed inside the premises of the fire extinguishing station, and used to protect at least two rooms.
Modular system includes modules with UWWTP installed directly in the room.
During the installation of ASGP, installation individual elements systems, commissioning works the following basic rules should be followed:
Equipment, components, devices must have technical passports, documentation certifying their quality (certificates), and comply with the project specifications, conditions of use.
All equipment used for the installation, installation of ASGP must serve at least 10 years (according to the technical passport).
The piping system must be symmetrical and evenly installed in the protected area.
Pipelines must be made of metal pipes. It is permissible to use a high pressure hose to connect the module to the pipeline.
The pipelines must be connected by welding or threaded connections.
The connection of the ASGP to the internal electrical networks of the building must be provided for the 1st category of power supply in accordance with the "Rules for the Installation of Electrical Installations".
Premises protected by ASGP must have light boards at the exit "Gas - go away!" and at the entrance to the premises "Gas - do not enter", warning sound signals.
Before installation, installation of equipment, pipelines, detectors fire alarm it is necessary to make sure that the volumes, areas, presence, dimensions of construction, technological openings, the existing fire load in the protected premises correspond to the data of the approved project.
MAINTENANCE OF GAS FIRE EXTINGUISHING SYSTEMS
Only specialized installation and commissioning organizations that provide services on the basis of a valid license of the Ministry of Emergency Situations of the Russian Federation for these types of activities are entitled to perform routine maintenance work to maintain automatic fire extinguishing systems in a working condition, as well as to carry out the installation, installation of ASGP.
Any amateur activity, including the involvement of employees of engineering services of an enterprise, organization, is fraught with unpleasant, often serious consequences.
Automatic gas fire extinguishing equipment, especially those operating under pressure, is quite specific and requires qualified handling. The conclusion of a service contract will relieve the owner, the head of the enterprise from the problems of the proper maintenance of the ASGP, the design, installation, the installation of which was spent a lot of money.
It is necessary to test the operability of the LRA equipment immediately before putting the system into operation, and then - once every five years. In addition, current routine maintenance (inspection, adjustment, painting, etc.), repair, replacement of equipment, if necessary, as well as weighing of cylinders, modules to establish the absence of a leakage ).
It should also be borne in mind that fire inspectors of the Ministry of Emergency Situations of the Russian Federation, when carrying out scheduled, operational checks of the fire regime in buildings, premises, must pay attention to the completeness, operability of the AGPS, the availability of technical documentation, and a service agreement with a licensed organization. In case of gross violations, the manager may be held accountable as established by law.
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Gas fire extinguishing
Gas fire extinguishing- This is a type of fire extinguishing, in which gas extinguishing compositions are used to extinguish fires and fires. An automatic gas fire extinguishing system usually consists of cylinders or containers for storing a gas extinguishing agent (GOS), gas stored in these cylinders (containers), control units, pipelines and nozzles that ensure the delivery and release of gas into the protected room, a control device and fire detectors.
History
Gas fire extinguishing in the server room. 1996 year
In the last quarter of the 19th century, carbon dioxide began to be used abroad as a fire extinguishing agent. This was preceded by the production of liquefied carbon dioxide (CO 2) by M. Faraday in 1823. At the beginning of the 20th century, carbon dioxide fire extinguishing installations began to be used in Germany, England and the United States, a significant number of them appeared in the 30s. After the Second World War, installations with the use of isothermal reservoirs for storing CO 2 (the latter were called low pressure carbon dioxide fire extinguishing installations) began to be used abroad.
Halons (halons) are more modern gaseous OTV. Abroad, at the beginning of the 20th century, halon 104, and then in the 30s, halon 1001 (methyl bromide) were used very limitedly for fire extinguishing, mainly in hand-held fire extinguishers. In the 50s in the USA research work which made it possible to propose halon 1301 (trifluorobromomethane) for use in installations.
The first domestic gas fire extinguishing installations (UGP) appeared in the mid-30s to protect ships and vessels. Carbon dioxide was used as a gaseous OTV (GOTV). The first automatic UGP was used in 1939 to protect the turbine generator of a thermal power plant. In 1951-1955. gas fire extinguishing batteries with pneumatic start (BAP) and electric start (BAE) have been developed. A version of the modular design of batteries with the help of type-setting sections of the CH type was used. Since 1970, the batteries have been using the GZSM locking and starting device.
In recent decades, automatic gas fire extinguishing systems have been widely used, using
ozone-safe freons - freon 23, freon 227ea, freon 125.
In this case, freon 23 and freon 227ea are used to protect the premises in which people are, or may be.
Freon 125 is used as a fire extinguishing agent to protect premises without permanent presence of people.
Carbon dioxide is widely used to protect archives and vaults.
Extinguishing gases
The operation of the gas fire extinguishing system in the server room
As extinguishing agents for extinguishing, gases are used, the list of which is defined in the Code of Rules SP 5.13130.2009 "Automatic fire alarm and fire extinguishing installations" (clause 8.3.1).
These are the following gas extinguishing agents: freon 23, freon 227ea, freon 125, freon 218, freon 318C, nitrogen, argon, inergen, carbon dioxide, sulfur hexafluoride.
The use of gases that are not included in the specified list is allowed only according to additionally developed and agreed standards (technical conditions) for a specific facility.
Gas extinguishing agents are classified into two groups according to the principle of fire extinguishing:
The first group of GOTV is inhibitors (freons). They have an extinguishing mechanism based on chemical
inhibiting (slowing down) the combustion reaction. Getting into the combustion zone, these substances intensively disintegrate
with the formation of free radicals, which react with the primary combustion products.
In this case, the burning rate decreases until it completely dies out.
The fire-extinguishing concentration of halons is several times lower than for compressed gases and ranges from 7 to 17 percent by volume.
namely, freon 23, freon 125, freon 227ea are ozone non-destructive.
The ozone depleting potential (ODP) of freon 23, freon 125 and freon 227ea is 0.
The second group is gases that dilute the atmosphere. These include compressed gases such as argon, nitrogen, inergen.
To keep burning necessary condition is the presence of at least 12% oxygen. The principle of diluting the atmosphere is that when compressed gas (argon, nitrogen, inergen) is introduced in the room, the oxygen content is reduced to less than 12%, that is, conditions are created that do not support combustion.
Liquefied gas extinguishing agents
Liquefied gas freon 23 is used without a propellant.
Freons 125, 227ea, 318Ts require pumping with a propellant to ensure transportation through pipelines to the protected area.
Carbon dioxide
Carbon dioxide is a colorless gas with a density of 1.98 kg / m³, odorless and does not support the combustion of most substances. The mechanism for stopping combustion with carbon dioxide lies in its ability to dilute the concentration of reactants to the limits at which combustion becomes impossible. Carbon dioxide can be discharged into the combustion zone in the form of a snow-like mass, while exerting a cooling effect. From one kilogram of liquid carbon dioxide, 506 liters are formed. gas. The fire extinguishing effect is achieved if the concentration of carbon dioxide is at least 30% by volume. Specific consumption gas in this case will be 0.64 kg / (m³ · s). Requires the use of weighing devices to control the leakage of fire extinguishing agent, usually tensor weighing devices.
Cannot be used to extinguish alkaline earth, alkali metals, some metal hydrides, developed fires of smoldering materials.
Freon 23
Freon23 (trifluoromethane) is a light, colorless and odorless gas. It is in the liquid phase in the modules. Possesses high pressure own vapors (48 KgC / sq. cm), does not require propellant pressurization. It is capable of creating a standard fire-extinguishing concentration in rooms located at a distance of more than 20 meters vertically and more than 100 meters horizontally from the modules with GEFU at the standard time (10/15 sec.). This quality makes it possible to create optimal fire extinguishing systems for objects with a large number of protected premises by creating a centralized gas fire extinguishing station. Environmentally friendly (ODP = 0). Recommended for the protection of premises with the possible stay of people. MPC = 50%, and fire extinguishing concentration - 14.6%. If HFC23 is released into a room from which people have not been evacuated (for some reason), then there will be no damage to their health!
Freon 125
Basic properties:
| 01. | Relative Molecular Weight: | 120,02 ; |
| 02. | Boiling point at a pressure of 0.1 MPa, ° С: | -48,5 ; |
| 03. | Density at 20 ° C, kg / m³: | 1127 ; |
| 04. | Critical temperature, ° С: | +67,7 ; |
| 05. | Critical pressure, MPa: | 3,39 ; |
| 06. | Critical density, kg / m³: | 3 529 ; |
| 07. | Mass fraction of pentafluoroethane in the liquid phase,%, not less: | 99,5 ; |
| 08. | Mass fraction of air,%, no more: | 0,02 ; |
| 09. | Total mass fraction of organic impurities,%, no more: | 0,5 ; |
| 10. | Acidity in terms of hydrofluoric acid in mass fractions,%, no more: | 0,0001 ; |
| 11. | Mass fraction of water,%, no more: | 0,001 ; |
| 12. | Mass fraction of non-volatile residue,%, no more: | 0,01 . |
Freon 218
Freon 227ea
Freon 318Ts
Freon 318ts (R 318ts, perfluorocyclobutane) Formula: C4F8 Chemical name: octafluorocyclobutane Physical state: colorless gas with faint odor
Boiling point -6.0 ° C (minus) Melting point -41.4 ° C (minus) Molecular weight 200.031 Ozone-depleting potential (ODP) ODP 0 Global warming potential GWP 9100 MPC r.z.mg / m3 r.z. 3000 ppm Hazard class 4 Fire hazard characteristic Non-combustible gas. In contact with a flame decomposes with the formation of highly toxic products Application Flame arrester, working substance in air conditioners, heat pumps
Compressed gas extinguishing agents (Nitrogen, argon, inergen)
Nitrogen
Nitrogen is used for phlegmatization of flammable vapors and gases, for purging and dehumidification of tanks and apparatus from residues of gaseous or liquid combustible substances. Cylinders with compressed nitrogen in a developed fire are dangerous, since their explosion is possible due to a decrease in the strength of the walls at high temperatures and an increase in gas pressure in the cylinder when heated. An explosion prevention measure is the release of the gas into the atmosphere. If this is not possible, the container should be sprinkled abundantly with water from the shelter.
Nitrogen cannot be used to extinguish magnesium, aluminum, lithium, zirconium and other materials that form nitrides with explosive properties. In these cases, argon is used as an inert diluent, much less often helium.
Argon
Inergen
Inergen - friendly towards environment fire fighting system, the active element of which consists of gases already present in the atmosphere. Inergen is an inert, that is, non-liquefied, non-toxic and non-flammable gas. It is 52% nitrogen, 40% argon, and 8% carbon dioxide. This means that it does not harm the environment and does not damage equipment or other items.
The extinguishing method inherent in Inergen is called "oxygen substitution" - the oxygen level in the room drops and the fire goes out.
- The Earth's atmosphere contains approximately 20.9% oxygen.
- The oxygen displacement method is to lower the oxygen level to about 15%. At this level of oxygen, the fire in most cases is unable to burn and will go out within 30-45 seconds.
- A distinctive feature of Inergen is its content of 8% carbon dioxide.
Physiologically, this is expressed in the ability of the human body to pump a larger volume of blood. As a result, the body is supplied with blood just as if a person were breathing normal atmospheric air.
One gas is replaced by another.
Others
Steam can also be used as a fire extinguishing agent, but these systems are mainly used for extinguishing inside technological equipment and in the holds of ships.
Automatic gas fire extinguishing installations
Light annunciators of the gas fire extinguishing system
Gas fire extinguishing systems are used in cases where the use of water can cause a short circuit or other damage to equipment - in server rooms, data warehouses, libraries, museums, aircraft.
Automatic gas fire extinguishing installations must provide:
In the protected room, as well as in adjacent ones that have an exit only through the protected room, when the installation is triggered, light devices must be switched on (a light signal in the form of inscriptions on light boards "Gas - go away!" And "Gas - do not enter!") And sound notification in accordance with GOST 12.3.046 and GOST 12.4.009.
The gas extinguishing system is also included as component in explosion suppression systems, used to phlegmatize explosive mixtures.
Testing of automatic gas fire extinguishing installations
The tests should be carried out:
- before putting the units into operation;
- during the period of operation at least once every 5 years
In addition, the weight of the waste water treatment plant and the pressure of the propellant in each vessel of the installation should be carried out within the time limits established by the technical documentation for the vessels (cylinders, modules).
Currently, when extinguishing a fire in rooms with electrical equipment, museums, archives, libraries and some other facilities, gas fire extinguishing is used as the most effective, environmentally friendly safe way fire fighting.
Compressed gases (nitrogen or argon) and freons are used as a fire extinguishing agent in gas fire extinguishing installations.
Pros of gas fire extinguishing
Gas fire extinguishing has a number of undeniable advantages over other types of fire extinguishing - aerosol, water, foam and powder. The main ones are:
- lightning speed of extinguishing fires;
- penetration of gases into hard-to-reach places the whole room;
- the possibility of lightning-fast liquidation of the consequences (with the help of ventilation);
- environmental safety for humans and lack of negative impact on the environment;
- no influence on property and material values.
In connection with such features, gas fire extinguishing is used in crowded places (due to the absolute harmlessness to the human body), museums, archives, libraries, rooms with electrical equipment, where it is important to preserve material values. They can function over a wide temperature range.
Components of gas fire extinguishing installations
The main components of an automatic gas fire extinguishing installation:
- a container with a fire extinguishing agent (cylinder or module);
- pipeline system (with nozzles);
- receiving and control device;
- Control block;
- detectors.
They are systems with a well-coordinated sequential algorithm of action; when designing them, specialists take into account a number of factors, including the properties of gases, the response of gas storage tanks to temperature changes.
In most cases, modular gas fire extinguishing installations are used in production and various facilities. A module is a cylinder, for the manufacture of which steel is used. A locking and starting device is placed on it - a valve to which a signal from a detector is received, as a result of which the locking device is activated. After use, the cylinder can be refilled with gas.
The mechanism of operation of the gas fire extinguishing installation consists in reducing the amount of oxygen in the room where the fire occurs by supplying a fire extinguishing agent - inert gas, carbon dioxide or freon.
Argon, nitrogen, argonite and inergen are used as inert gases in installations, which do not have a negative effect on people and can be used to extinguish electrical equipment. Plants with carbon dioxide use carbon dioxide.
How is fire extinguishing using gases - general principle consists in the fact that under high pressure non-combustible gases enter the fire site, which significantly reduce the oxygen concentration in the air, slowing down the combustion process.
- The sensors located in the room send information to the control panel about the beginning of the fire.
- After informing about a fire that has started, ventilation is blocked.
- Through pipelines with the use of sprays, the gas goes outside, and with its increased concentration, it is possible to put out the fire faster.
The process of gas fire extinguishing does not exceed 60 seconds, while the gas is evenly distributed throughout the room. After working out the system, to eliminate the consequences of using gas, it is enough to ventilate the room.
The principle of operation is quite simple, and the complex itself allows you to cope with the source of fire in a matter of seconds, without causing harm to property and people's lives.
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