What a fire extinguishing agent is used in fire extinguishing installations. The use of fire extinguishing agent in gas fire extinguishing installations. Types used

The gas fire extinguishing system is an extremely effective installation for the operational liquidation of the fire at the initial stage of ignition. Its special value is the lack of additional damage to the fire extinguishing agent protected equipment stored by documents, artistic values.

The inevitable effect of water, chemical foam, powders for building structures, decoration decoration, furniture, office, household appliancesThe documentation during the extinguishing of the fire often leads to direct and indirect material losses, quite comparable with the flames, combustion products.

Filling the volume of the room with a mixture of inert gases that are non-consisting with burning materials quickly reduces the oxygen content (less than 12%), making the combustion process. Gas fire extinguishing systems use:

• liquefied gases - chladones (coal - fluoride compounds used as refrigerants), sixfluoride sulfur (SF6), carbon dioxide (CO2);
• compressed gases - nitrogen, argon, argonite (50% nitrogen + 50% argon), inergen (52% nitrogen + 40% Argon + 8% CO2).

Applied gases, mixtures thereof to certain concentrations (!) In the air are not dangerous to the health of people, and also do not destroy the ozone layer.

The automatic gas fire extinguishing system (ASSP) is a set of storage vessels of liquefied, compressed fire extinguishes, supplying pipelines with nozzles, motivating (signal-starting) devices, control node. There are several ways to turn on asGP:

• auto;
• remote;
• local.

The last two species are duplicate, auxiliary ways that ensure the start of the fire extinguishing system during the failures of the automatic fire alarm system. They are used by a manual trained personnel of the enterprise, security service staff from the fire extinguishing station of the centralized gas fire extinguishing system or from the system startup device installed before entering the room.

According to the type of object protection, the automatic gas fire extinguishing system is distinguished:

Systems of volume fire extinguishing.

It is used for operational filling of the gas mixture of the room or a group of premises of the building, where there is expensive technological, electrical equipment, material, artistic values.

Local fire extinguishing systems.

Used to eliminate fire focus on separate technological equipment, if the extinguishing of the entire volume is impossible.

The need to apply an automatic fire extinguishing system, its type, view of the fire extinguishing gas for various buildings, premises, equipment is determined by the current state regulations, the rules in the field of fire protection.

Installation and installation of a gas fire extinguishing system

To determine the need to design an automatic fire extinguishing system, the documentation development exist two main documents in this field of fire provisionalization: NPB 110-03, SP 5.13130.2009, regulating all design issues, installation of installations automatic fire extinguishing.

In addition, the following official documents are used to calculate the design, installation, installation of the gas fire extinguishing system:

Fire safety standards,

Federal standards (GOST R), which determine the composition, methods of installation, installation, methods and timing of testing, testing the performance of the fire extinguishing system with a gas mixture at the end of the installation, commissioning.

There are also sectoral, departmental norms of the ASGP device, which take into account the specifics of objects, the properties of used substances, materials.

According to paragraph 3 of the NPB 110-03, the type of automatic installation, the choice of fire extinguishing agent, the form, the fire extinguishing method, the type of equipment used is determined by the design organization based on the construction, structural, technological parameters of protected objects. As a rule, the gas fire extinguishing systems are design, installed, set the type solutions of the ASPP stations in the following categories of objects to be protected:

The buildings of federal, regional, special archives, where rare publications are stored, various reports, documentation, which is of particular value.

Unnwided technical sets of radio centers, radio relay stations.

Unattended premises of hardware complexes of cellular base stations.

Auto ATS with switching equipment, placing electronic stations, nodes, centers, numbers of numbers, channels 10 thousand and more.

Storage premises, issuing rare publications, manuscripts, important reporting documentation in public, administrative buildings.

Storages, stores of museums, exhibition complexes, art galleries of federal, regional importance.

Premises of computer complexes used in technological management, which will stop the security of personnel, pollution ambient.

Server, archives of various media.

The last item also applies to modern data processing centers, data centers with expensive equipment.

Primary data for project development, calculations, further installation, installation of automatic fire extinguishing are: a list of protected premises, the presence of suspended ceilings, technical veils (raisedpins), geometry, water volume, the size of the enclosing structures, the parameters of technological, electrical equipment.

Centralized ASGP Call a system containing cylinders with states installed indoors of fire extinguishing station, and used to protect at least two rooms.

Modular system Includes modules with states installed directly indoors.

During the installation of ASGP, installation individual elements Systems, commissioning should follow the following basic rules:

Equipment, components, devices must have technical passports, documentation certifying their quality (certificates), and comply with the project specifications, the conditions of application.

All equipment used for installation, installation of ASD, must serve at least 10 years (according to the technical passport).

The pipeline system must be symmetrical, uniformly installed in the protective room.

Pipelines must be performed from metal pipes. To connect the module to the pipeline, it is permissible to use high pressure sleeve.

The connection of pipelines must be welding or threaded connections.

Connecting the ASD to the internal power grid of the building must be provided by 1 category of power supply in accordance with the rules of the electrical installation device.

Premises, protected asgps, should have light boards at the output of "Gas - Leave!" And at the entrance to the room "Gas - not to enter", warning sound signals.

Prior to installation, installation of equipment, pipelines, fire alarm detectors, make sure that the volumes, areas, the presence, the size of construction, technological openings, the existing fire load in the protected areas, comply with the data of the approved project.

Maintenance of gas fire extinguishing systems

To carry out regulatory work to maintain automatic fire extinguishing systems in a working condition, as well as carry out installation, installation of ASSP, only specialized installation and commissioning organizations are entitled to provide services on the basis of the current MOE license for these activities.

Any amateurness, including the involvement of enterprise engineering services, organizations, unpleasant, often by severe consequences.

Gas automatic fire extinguishing equipment, especially working under pressure, quite specific, requires a qualified handling of it. The conclusion of a service agreement will save the owner, the head of the enterprise from problems on the proper content of ASSP, on the design, installation, the installation of which considected by considerable means.

It should be carried out by testing the performance of the ASD equipment immediately before the commissioning system, and then 1 every five years. In addition, current regulations are needed (inspection, adjustment, painting, etc.), repair, replacement of equipment if necessary, as well as weighing cylinders, modules to establish the absence of the leakage of the state within the time set in technical passports on the vessels (containers ).

It is also necessary to take into account that the Inspectors of the Fire Supervision of the Ministry of Emergency Situations of the Russian Federation during scheduled, operational checks of fire regime in buildings, premises necessarily pay attention to the staffing, the efficiency of AGPS, the availability of technical documentation, a service contract with a licensed organization. In case of gross violations, the head can be brought to justice established by law.

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24.12.2014, 09:59

S. Sinelnikov
Head of the Project Department of LLC "Tehnos-M +"

Recently, in systems of fire safety of small objects to be protected by automatic fire extinguishing systems, automatic gas fire extinguishing systems are becoming increasingly distributed.

Their advantage is relatively safe fire-standing compositions, the fully absence of damage to the protected object when the system is triggered, repeatedly use the equipment and extinguishing the fire focus in hard-to-reach places.

When designing installations, questions often arise on the choice of fire extinguishing gases and hydraulic calculation of installations.

In this article we will try to reveal some aspects of the problem of the choice of fire extinguishing gas.

All the most common gas fire extinguishing compositions can be conditionally divided into three main groups. These are the substances of the refrigerated series, carbon dioxide is widely known as carbon dioxide (CO2) - and inert gases and mixtures thereof.

In accordance with the NPB 88-2001 *, all of these gas fire extinguishes are used in fire extinguishing facilities for extinguishing fires Class A, B, C, according to GOST 27331, and electrical equipment with voltage not higher than those specified in the technical documentation used by GOTV.

Gas affects are used mainly for bulk fire extinguishing in the initial stage of the fire according to GOST 12.1.004-91. Also, hundreds are used for phlegmatization of an explosive environment in chemistry oil, chemical and other industries.

HOTEL non-electric conductives, easily evaporate, do not leave traces on the equipment of the protected object, in addition, the important dignity of the MOTS is their

fitness to extinguish expensive electrical installationsStress.

It is prohibited to use GOTS for extinguishing:

a) fibrous, bulk and porous materials capable of self-burning with the subsequent flow of the layer inside the volume of the substance (wood sawdust, rags in bales, cotton, herbal flour, etc.);

b) chemicals and their mixtures, polymeric materials, prone to degeneration and burning without air access (nitrocellulose, powder, etc.);

c) chemically active metals (sodium, potassium, magnesium, titanium, zirconium, uranium, plutonium, etc.);

d) chemicals capable of subjected to car decay (organic peroxide and hydrazine);

e) metal hydrides;

e) pyrophoric materials (white phosphorus, metal organic compounds);

g) oxidizing agents (nitrogen oxides, fluorine). It is prohibited to extinguish the fires of the class C if it is possible to allocate or enter the protected volume of combustible gases with the subsequent formation of an explosive atmosphere.

In the case of the use of GOTS for fire protection of electrical installations, the dielectric properties of gases should be taken into account: dielectric constant, electrical conductivity, electrical strength.

Typically, the limit voltage at which extinguishing without turning off the electrical installations by all GOTOS is not more than 1 kV. To extinguish electrical installations with a voltage up to 10 kV, only CO2 of the highest grade can be used - according to GOST 8050.

Depending on the extinguishing mechanism, gas fire extinguishing compositions are divided into two qualifications:

1) inert diluents that reduce the oxygen content in the burning zone and the inert medium forming in it (inert gases - carbon dioxide, nitrogen, helium and argon (species 211451, 211412, 027141, 211481);

2) inhibitors that hinder the combustion process (halogen farmers and their mixtures with inert gases - chladones).

Depending on the aggregate state, the gas fire extinguishing compositions under storage conditions are divided into two classification groups: gaseous and liquid (liquids and / or liquefied gases and gases in liquids).

The main criteria for selecting the gas fire extinguishing agent are:

■ Safety of people.

■ Technical and economic indicators.

■ Saving equipment and materials.

■ Application restriction.

■ Environmental impact.

■ Ability to remove GOTV after use.

Preferably, apply gases that:

■ have acceptable toxicity in used fire extinguishing concentrations (suitable for breathing and allow to evacuate staff even when gas supply);

■ thermally racks (form the minimum amount of thermo-arms products, which are crirrow-zyon-active, irritating mucous membrane and poisonous inhalation);

■ most effective during fire extinguishing (protect the maximum volume when feeding from the module, which is filled with gas to the maximum value);

■ economical (provide minimal specific financial costs);

■ Eco-friendly (do not have a destructive action on the ozone layer of the Earth and do not contribute to the creation of the greenhouse effect);

■ Provide universal methods for filling modules, storage and transportation and rewrings. The most effective in fire extinguishing are chemical chladones. The physico-chemical process of their action is based on two factors: chemical inhibition of the process of oxidation reaction and reduce the concentration of oxidizing agent (oxygen) in the oxidation zone.

Undoubted advantages have chladone-125. According to the NPB 882001 *, the regulatory fire extinguishing concentration of chladone-125 for fires of class A2 is 9.8% of. Such a concentration of chladone-125 can be increased to 11.5% vol., At the same time, the atmosphere is suitable for breathing for 5 minutes.

If you rank up to toxicity with a massive leakage, then the smaller gases are the least dangerous, because Carbon dioxide ensures human protection from hypoxia.

The chladones used in systems 88-2001 *) are low-toxic and do not show a pronounced inxication pattern. By toxicokinetics, chladones are similar to inert gases. Only with the long-term inhalation effects of low concentrations of chladones can have an adverse effect on cardiovascular, central nervous system, lungs. With the inhalation effects of high concentrations of chladone, oxygen starvation is developing.

Below is a table with the temporal values \u200b\u200bof the safe residence of a person in the medium of chladone brands most frequent in our country at different concentrations (Table 1).

Concentration,% (vol.)			10,0 | 10,5 | 11,0				12,0 12,5 13,0
Safety time, min.
Cold 125HP
Cladon 227EA

The use of chladones when caring fires is almost safe, because OG-wing concentrations for chladones are an order of magnitude less than fatal concentrations with the duration of exposure to 4 hours. The thermal decomposition is approximately 5% of the mass of the refrigeration filed to extinguish the fire, therefore the toxicity of the medium formed when cutting the fire with chladones will be much lower than the toxicity of pyrolysis products and decomposition.

Claudone-125 refers to ozone-protected. In addition, it has the maximum thermal stability compared to other chladones, the temperature of thermal arms of its molecules is more than 900 ° C. The high thermal stability of chladone-125 allows it to be used to extinguish fireflows, because At temperatures of the tension (usually about 450 ° C), the thermograph is practically not occurring.

Claudone-227ea is no less safe than chladone-125. But their economic indicators in the composition of the fire extinguishing installation are inferior to chladone-125, and efficiency (protected volume from a similar module) is slightly different. He is inferior to chladone-125 and thermal stability.

The specific costs of CO2 and Coldone-227ea almost coincide. CO2 is thermally stable during fire extinguishing. But the effectiveness of CO2 is small - a similar module with chladone-125 protects the volume by 83% more than the CO2 module. The fire extinguishing concentration of compressed gases is higher than the refrigeration, therefore it takes 25-30% more gas, and, therefore, the number of tanks for the storage of gas fire extinguishes increases.

Effective fire extinguishing is achieved at CO2 concentration of more than 30% vol., But such an atmosphere is unsuitable for breathing.

Carbon dioxide at concentrations of more than 5% (92 g / m3) has a harmful effect on human health, the volume fraction of oxygen in the air is reduced, which can cause the phenomenon of oxygen insufficiency and choking. Liquid carbon dioxide with a decrease in pressure to atmospheric turns into gas and snow temperature -78.5 ° C, which cause skin charm and lesion of the mucous membrane of the eye.

In addition, when using coal acid installations of automatic fire extinguishing temperature of the surrounding air of the working area should not exceed + 60 ° C.

In addition to refrigerants and CO2, inert gases (nitrogen, argon) and mixtures thereof are used in gas fire extinguishing installations. Unconditional environmental friendliness and safety for the person of these gases are undoubted advantages of their use in augpt. However, a high fire extinguishing concentration and the associated greater (compared to chladones) the amount of the required gas and, accordingly, a greater number of modules for its storage, make such installations more cumbersome and expensive. In addition, the use of inert gases and their mixtures in augpt is associated with the use of higher pressure in modules, which makes them less safe during transportation and operation.

In recent years, modern flavors of the new generation in the domestic market began to appear.

These special compositions are mainly produced abroad and have, as a rule, high cost. However, their low fire extinguishing concentration, eco-logicalicity and the ability to use low pressure modules make their use attractive and promise good prospects for using such GOTV in the future.

Based on all above, it can be said that chladones are most effective and accessible at this time of fire extinguishes. The relatively high cost of chladon is compensated by the cost of the installation itself, the installation of the system and its maintenance. Especially important quality of refrigerants used in fire extinguishing systems (in accordance with the NPB 88-2001 *), there are their minimally harmful effects per person.

Table. 2. Summary table of characteristics of the most consumed in the territory of the Russian Federation

CHARACTERISTIC	Gas fire extinguishing substance
Name GOTV	Carbon dioxide		Cold 125.	Cold 218.	Cladon 227EA	Cladon 318c	Six-fluorin
Name options	Carbon dioxide	TFM18, Fe-13.			FM200, Imemer-2.
Chemical formula										N2 - 52%, AG - 40% CO2 - 8%
		TU 2412-312 05808008.	TU 2412-043 00480689.	TU 6-021259-89	TU 2412-0012318479399.	TU 6-021220-81
Fire classes	AND ALL Up to 10,000 B.
Fire extinguishing efficiency (class of fires A2 n-heptane)
Minimum bulk fire extinguishing concentration (NPB 51-96 *)
Relative dielectric constant (N2 \u003d 1.0)
Filling coefficient modules
Aggregate state in the AUPT modules	Liquefied gas	Liquefied gas	Liquefied gas	Liquefied gas	Liquefied gas	Liquefied gas	Liquefied gas	Compressed gas	Compressed gas	Compressed gas
Mass control GOTV	Weighting device	Weighting device	Manometer	Manometer	Manometer	Manometer	Manometer	Manometer	Manometer	Manometer
Pipe layout	With no restrictions	With no restrictions	Taking into account the bundle	With no restrictions	Taking into account the bundle	Taking into account the bundle	Bed restrictions	With no restrictions	With no restrictions	With no restrictions
Need order
Toxicity (Noael, Loael)					9,0%, > 10,5%
Fire load interaction	Strong cooling		\u003e 500-550 ° С	\u003e 600 ° C highly toxic				Absent	Absent	Absent
Methods of calculation	MO, LPG NFPA12		MO, ZALP, NFPA 2001		MO, ZALP, NFPA 2001
Availability of certificates					FM, UL, LPS, SNPP
Warranty period of storage
Production in Russia

Installations of gas fire extinguishing are specific, expensive and fairly difficult to design and edit. To date, there are many companies that offer various gas fire extinguishing installations. Since there is little information in open sources of gas fire extinguishing, then many companies enter the customer's misleading, exaggerating advantages or hiding the shortcomings of certain gas fire extinguishing installations.

The presence of an automatic fire extinguishing system on any facility of the national economy is regulated by regulatory acts. Installing such systems is required in rooms where important information is stored (for example, in the server room). They are needed on closed car parking, warehouses, repair workshops different products. Other premises should also be equipped with such means of protection depending on the area of \u200b\u200bthe territory and functional purpose.

Gas fire extinguishing is one of the types of automatic fire extinguishing.

Such subsystems are a reservoir, which is filled with a special substance designed to extend the focus of ignition, as well as a combination of special managers and controlling devices, pipelines and sprayers. Automatic fire extinguishing systems are classified depending on the substances that apply. In practice, gas, water, foam, water-foam, powder, aerosol fire extinguishing, as well as the repayment of the fire with thin water is used.

The main aspects of gas fire extinguishing

Gas fire extinguishing is a separate type of fire elimination, in which special gas substances are used. This method is optimal, since when the protective line is triggered, all the equipment located in the room is preserved and is not exposed to special means of extinguishing fires. This subsystem is more expensive than the rest. In practice, this type of protection is installed in hermetically closed rooms or storage places of valuable things. The use of gas allows you to extinguish the fire effectively, since they are filled with the entire perimeter of the object. Gas penetrates hard-to-reach places where foam or powder can enter.

On video - Presentation of the gas fire extinguishing system:

The advantages of applying gas fire extinguishing system are:

• Lack of negative effect on the ozone layer;
• When using gas, a greenhouse effect is not formed;
• Such specialists have a long shelf life;
• In the event of contact with fire, poisonous or toxic compounds are not formed;
• Short-term fire extinguishing;
• There are no significant atmospheric pressure drops;
• The gas fire extinguishing system allows the fire in several rooms at the same time.

The use of such fire fights may have a modular and centralized management type. Large financial costs are required when installing equipment. An important aspect It is timely filling with stewing substance of modules after automatic response system. The use of gas in order to extinguish the fire is classified into three classes on the basis of the subject, the fire of which happened:

• Class "A" - solid combustible substances and materials (plastic, fabric, paper, wood, etc.);
• Class "B" - flammable fuel and lubricants (oil, petroleum products, gasoline, varnishes, paints, etc.);
• Class "C" - combustible gases.

Gas fire extinguishing according to current safety standards may include the following fire extinguishes:

• Carbon dioxide (CO2);
• Coldone (CF3H), 125 (C2F5H), 218 (C3F8), 227 (C3F7H), 318 (C4F8H);
• Sulfur sixfluoride (SF6);
• Argon (AR);
• Nitrogen;
• Inergen;
• Argonite;
• Gas mixes.

Complex composition of gas extinguishing systems

Gas fire extinguishing systems consist of the following components:

• Special modules;
• Distribution devices;
• Nozzles;
• Pipelines.

Special modules (containers) are designed for gas storage. When automatically activated the device, the gas is displayed through pipelines. Modules are made in the form of cylinders. Cylinders are equipped with a shut-off mechanism. They can be made of various materials. Depending on the functional features Systems in general, volume and pressure can also be diverse. As practice shows, high-strength steel is used for the manufacture of cylinders. On the inside of the capacitance is coated with a polymer substance. This processing performs an anti-corrosion function.

The locking and starting mechanism works with the help of an electromagnet or a pyropatron. With a large area of \u200b\u200bthe room, gas extinguishing fire includes several installations, and for small rooms is enough one. Distributing devices are installed to move the stewing substance into the pipeline. This device is presented in the form of a triple valve. The design is equipped with a locking valve and a mechanism that allows you to lift the substance and direct it into the pipeline.

The gas distribution mechanism can be performed manually or remotely.

Nozzles allow you to spray stewing substance. They are installed, as a rule, on pipelines. The nozzle creates a pressure under which gas comes out. The prescribed pressure allows you to determine the spraying range. Spraying should be made comprehensively: at an angle of 360º. Pipelines transport gas to nozzles. Gas fire extinguishing is designed according to various technical parameters. The cross section, the volume and length of pipelines is determined individually for each room so that the gas supply is operational. In places with a large fire hazard coefficient, steel pipelines are used.

Scope of the system

Gas fire extinguishing is intended for use in premises where valuable things are located or expensive equipment. For example, in server rooms where electronic equipment is installed, just such a system should be mounted. The use of water, powder or foam when extinguishing the fire can lead to the exit of the equipment. This type of fire extinguishing is used in places where relics are stored, historical cultural monuments: in museums, libraries.

Along with the use of gas to extinguish the fire, insulation technology can be used. In the presence of special InstallationsIn the event of a focus of ignition, oxygen access is eliminated. The oxygen level is reduced to a minimum, in which the maintenance of the combustion process is impossible. In places of large cluster of people (airport stations) for gas systems, special compositions are used. In such cases, it is impossible to limit oxygen access. Each fire extinguishing system is designed individually, taking into account the set of factors.

The video shows how the gas fire extinguishing of the production premises is performed:

Designing the installation of a gas fire extinguishing complex

When installing a gas fire extinguishing line on the object, a working draft must be drawn up, which includes the following sections:

• Explanatory note;
• Technological part;
• Electrical part;
• Description of the specifics of equipment and materials;
• Estimate (its presence depends on the requirements of the customer).

An explanatory note must necessarily contain general provisions, purpose, brief description of the protected object. The general provisions indicate the basis of the design of the system and the name of the object. It is necessarily listed by the regulatory documents that were used in the preparation of project documentation. Next specifies the model gas installation, Its purpose and functionality. The characteristic of the room contains an indication of the area of \u200b\u200bthe protected object. The following indicators are noted:

• Atmosphere pressure;
• Air temperature;
• Humidity;
• Technical characteristics of ventilation;
• Features of structures;
• Classified zones.

The technological part of the documentation contains a description of the complex installation of fire extinguishing. All components are described: the type of module, fire safety certificates, sprayers, nozzles, pipelines, etc. In the same subsection, the calculation formulas that contain information on the concentration of stewing substance in a particular room are presented. One of the main formulas is the calculation of the time to evacuate all people from the room. Accurately indicates the time of termination of the equipment. On average, this time is 10 seconds. The delay in the operation of the automatic fire extinguishing system with gas is undesirable, since it is intended to eliminate the focus of fire at an early stage.

When performing calculations, it is necessary to take into account the designs that are constantly open.

The electrical section of the documentation contains the following provisions:

• Principles of choosing devices notifying the emergence of a fire;
• Their name, type, certificate number;
• A description of the receiving, control and control mechanisms, their serial numbers and certificate numbers;
• Briefly describe the functionality of the device;
• The principle of operation of the equipment (necessarily includes four subsections, including the "Automatics and turned off" modes, remote and modular start, power supply);
• Elemental composition and their placement;
• Place of installation and technical requirements for it;
• Marking of wires, cable, the order of their masonry;
• The composition of persons (professional and qualifying), which make installation and maintenance of equipment;
• Description of the necessary qualifying level;
• The number of service personnel;
• List of labor protection measures;
• Safety instructions;
• Requirements for persons servicing mechanisms;
• Algorithm of actions in case of operation of the system and the emergence of fire.

Design, installation, as well as fire extinguishing systems service perform specialized firms.

Gas fire extinguishing has more than a century of history. Apply carbon dioxide (CO2) to extinguish fires for the first time began at the end of the 19th century in countries Western Europe and USA but widespread this method Fire extinguishing only after World War II, when chladones began to apply as the main component of the state.

Basics and classification

Currently, the regulatory documents currently active in the Russian Federation allow the use of gas fire extinguishing compositions based on carbon dioxide, nitrogen, argon inergen, sixfluoride sulfur, as well as refrigeration 227, chladone23, chladone 125 and chladone 218. According to the principle of operation, all states can be divided into two groups:

Deoxidants (oxygen displays) - substances that create a concentrated cloud that obstructs the influx of oxygen and "suffocating" in this way the focus of ignition. This group includes state based on carbon dioxide, nitrogen, argon and inergen.

Inhibitors (burning suppressors) are substances that enter the burning substances into chemical reactions that take energy from the combustion process.

According to the method of storage, fire extinguishing gas is divided into compressed and liquefied.

The scope of gas installations of fire extinguishing covers industries in which stealing water or foam is undesirable, but also unwanted contact of equipment or stored reserves with chemically aggressive powder mixtures - Hardware halls, server, computing centers, sea and aircraft, archives, libraries, museums, art galleries.

Most substances applied to the production of state are not toxic, however, the use of gas fire extinguishing systems creates a closed medium that is unsuitable for life (this applies to the state from the deoxidant group). Therefore, fire extinguishing gas systems present a serious danger of people's lives. So on November 8, 2008, during the running tests of the atomic submarine "Nerpe", the unauthorized response of a gas extinguishing system has led to the death of more than twenty crew of the submarines.

In accordance with regulatory acts, all automatic fire extinguishing systems with the state as a working substance must necessarily allow the possibility of delaying the filing of the mixture to the full evacuation of personnel. Premises in which automatic gas fire extinguishing is used, equipped with light boards "Gas! Do not go! " And "Gas! Leave! " At the entrance to the room and outlet of it, respectively.

Advantages and disadvantages of gas fire extinguishing

Fire extinguishing with the help of state gained widespread due to a number of advantages, including:

• fire extinguishing with the help of state is carried out throughout the size of the room;
• non-toxic fire extinguishing gas, chemically inert, when heated and contact with burning surfaces do not disintegrate into poisonous and aggressive fractions;
• gas fire extinguishing practically does not harm equipment and material values;
• after graduation, the state is easily removed from the room by simple ventilation;
• the application of the state has a high fire extinguishing.

However, gas fire extinguishing has the same drawbacks:

• fire extinguishing gas requires room sealing
• gas fire extinguishing is ineffective in the premises of a large volume or in the open space.
• storage of oven gas modules and maintenance of the fire extinguishing system are associated with difficulties that accompany the storage of substances under pressure
• gas fire extinguishing installations are sensitive to temperature regime
• The state is unsuitable for extinguishing metals, as well as substances that are able to burn without access of oxygen.

Fire extinguishing installations with the help of state

Installations of gas extinguishing fire according to the degree of mobility can be divided into three groups:

Mobile gas fire extinguishing installations - fire extinguishing installations mounted on a wheel or tracked chassis, towed or self-propelled (installation of gas fire extinguishing "Sturm").

Portable primary extinguishing agents - fire extinguishers and fire extinguishing batteries.

Stationary installations - mounted inpatient installation of fire extinguishing with state, automatic and operating on the command from the remote control.

IN non-residential premises, in warehouses and storage facilities, in enterprises related to the production and storage of combustible and explosive substances Automatic gas fire extinguishing systems are widely used.

Automatic Gas Fair System Scheme

Since the fire extinguishing gas has a high danger to the staff of the enterprise, in the event of an automatic fire extinguishing system with the help of the state at enterprises with a large number of employees, the integration of the system of system with control and access control system is required. In addition, the automatic fire extinguishing system should at a signal of fire sensors carry out maximum sealing of the room in which extinguishing is to turn off the ventilation, as well as close the automatic doors and lower the protective rolets, if there are those.

Automatic gas fire extinguishing systems are classified:

In terms of extinguishing - the extinguishing of full volume (the entire area of \u200b\u200bthe room is filled) and local (gas is supplied directly to the heart rate).

On the centralization of the supply of a fire extinguishing mixture - centralized (gas is served from the central tank) and modular.

According to the method of initiation of the extinguishing process - with electric, mechanical, pneumatic, hydraulic descent, or by their combination.

Equipment of the object of the gas fire extinguishing system

The primary calculation and installation planning of the gas fire extinguishing system begins with the selection of the parameters of the system, depending on the specifics of a particular object. Of great importance is the right choice of fire extinguishing agent.

Carbon dioxide (carbon dioxide) is one of the most affordable options for fire extinguishing. Refers to dioxidant fire extinguishes, also has a cooling effect. Stored in liquefied state, requires weight control of the leakage of the substance. Mixtures based on carbon dioxide are universal, restrictions on use are fires with alkali metal ignition.

Gas cylinders

Cladon 23 is also stored in liquid form. Due to its high pressure, it does not require the use of outstanding gases. It is allowed to use for extinguishing rooms, in which people stay possible. Environmentally safe.

Nitrogen - inert gas, is also used for use in fire extinguishing systems. It has a low cost, however, due to storage in a compressed form, the modules are explosive. If the gas fire extinguishing module has not worked, it is necessary to rush to irrigate water from the shelter.

Limited use has steam fire extinguishing installations. Used on objects generating pairs for their work, for example on power plants, courts with steam turbine engines, etc.

In addition, before designing, you must select the type of fire extinguishing gas installation - centralized or modular. The selection depends on the size of the object, its architecture, the floors and the number of individual premises. Installation of the fire extinguishing installation of a centralized type is suitable for protecting three and more rooms within a single object, the distance between which does not exceed 100m.

It should be taken into account that centralized systems are subject to large quantity The requirements of the regulatory NPB 88-2001 are the main regulatory document regulating the design, calculation and installation of fire protection plants. Fire extinguishing gas modules in their execution are divided into unitary modules - include one container with a compressed or liquefied gas mixture with a gas and gas stipulated; And the batteries are several cylinders connected by the collector. Based on the plan, a gas fire extinguishing project is being developed.

Designing a fire system with the use of state

It is desirable that the entire complex of works related to the equipment of the object by the fire system (design, calculation, installation, adjustment, maintenance) was carried out by one executor. Designing and calculating the gas fire extinguishing system is made by the representative of the installer in accordance with the NPB 88-2001 and GOST R 50968. The calculation of the installation parameters (the number and type of fire extinguishing agent, centralization, the number of modules, etc.) is made on the following parameters:

• the number of rooms, their volume, the presence of suspended ceilings, falseland.
• area of \u200b\u200bconstantly open openings.
• temperature, barometric and hygrometric (air humidity) mode on the object.
• the presence and mode of personnel operation (paths and time of personnel evacuation in case of fire).

When calculating the estimates on the installation of fire extinguishing equipment, some specific aspects should be taken into account. For example, the cost of one kilogram of fire extinguishing gas market is greater when using compressed gas modules, since each such module contains a smaller mass of a substance than a module with liquefied gas, therefore, the latter will need less.

The cost of mounting and maintenance of a centralized extinguishing system is usually less, however, if the object has several sufficiently remote premises, the savings "eaten" the cost of pipelines.

Installation and maintenance of gas fire extinguishing station

Before starting installation work on the assembly of gas fire extinguishing installation, make sure that the availability of certificates to the mandatory certification equipment and check the availability of a license to work with gas, pneumatic and hydraulic equipment from the installer firm.

The room equipped with a gas fire extinguishing station is mandatory equipped with exhaust ventilation to remove air. The multiplicity of air removal is equal to three for chladones and six for deoxidants.

The manufacturer carries out the fire extinguishing modules or centralized balloon tanks, trunk and distribution pipelines and starting systems. The modular or centrally pipeline part of the gas extinguishing station is integrated into a single automated control system and control.

Pipelines and elements of the automated control system should not disturb the appearance and functionality of the premises. At the end of installation and adjustment, the act of completed work is drawn up, and the act of acceptance and transmission to which the test protocols and technical passports of the used equipment are attached. The contract for maintenance.

Equipment performance tests are repeated at less often than once every five years. Maintenance of gas extinguishing systems includes:

• regular tests of performance of gas extinguishing station elements;
• regulatory work I. maintenance equipment;
• weight tests of modules for the absence of leakage of state.

Despite certain difficulties associated with installation and use, gas extinguishing systems have a number of undoubted advantages and high efficiency in their field of application.

A technical and economic comparison showed that in order to protect the premises of more than 2000 m3 in the UGP, it is more expedient to use isothermal modules for liquid carbon dioxide (mp3).

Moju consists of an isothermal reservoir for CO2 storage, with a capacity of 3000 l to 25000l, shut-off and starting device, instruments for controlling the amount and pressure CO2, refrigeration units and control cabinets.

From the ISP in our market, applying isothermal tanks for liquid carbon dioxide, mute Russian production In terms of its technical characteristics, overseas products are superior. Isothermal reservoirs of foreign production must be installed in heated room. The mission of domestic production can be operated at ambient temperature up to minus 40 degrees., Which allows you to install isothermal tanks outside the buildings. In addition, in contrast to foreign articles, the design of the Russian mission allows the submission to the protected room CO2, dosing by weight.

Cladon Nozzles

For the uniform distribution of GOTV in the volume of the protected room on the distribution pipelines, the UGP is installed nozzles.

Nozzles are installed on the outlet openings of the pipeline. The design of the nozzle depends on the type of gas supplied. For example, for the supply of refrigeration 114V2, which under normal conditions is a liquid, two-rigs were previously used with the impact of the jets. Currently, such nozzles are recognized as ineffective regulatory documents recommended to replace them on hooks of a jack-type or centrifugal, providing fine spliced \u200b\u200bchladone type 114V2.

For supplying refrigerations type 125, 227EA and C02, a radial type nozzle is used. In such nozzles, the flows of gas incoming in nozzles and extending gas jets are approximately perpendicular. Radial type nozzles are divided into ceiling and walls. Ceiling nozzles can supply gas jets to sector with an angle of 360 °, walls - about 180 °.

An example of the use of radial-type ceiling nozzles as part of augps is shown on fig. 2.

The placement of nozzles in the protective room is carried out in accordance with the technical documentation of the manufacturer. The number and area of \u200b\u200bthe outlet openings of the nozzles is determined by the hydraulic calculation, taking into account the flow rate and the map of the dispenser specified in the technical documentation for the nozzle.

AUGP pipelines are made from seamless pipes, which ensures the preservation of their strength and tightness in dry rooms for a period of up to 25 years. Applied pipe connection methods - welded, threaded or flange.

To maintain the expenditure characteristics of pipeline wiring over a long period of operation, the nozzles should be made from corrosion-resistant and durable materials. Therefore, advanced domestic firms do not apply nozzles from aluminum coating alloys, and only brass nozzles use.

The right choice of UGP Depends on many factors.

Consider the main of these factors.

Method of fire protection.

UGPs are designed to create a gas environment that does not support the combustion in the protected room (volume). Therefore, there are two ways to fire extinguishing: volumetric and locally volumetric. The overwhelming majority applies a volumetric method. Local in terms of volume from an economic point of view is beneficial in the case when protected equipment is installed indoors of a large area, which is not fully protected by regulatory requirements.

In NPB 88-2001, regulatory requirements are given at the locally and volume method of fire extinguishing only for carbon dioxide. Based on the data of the regulatory requirements, it follows that conditions exist under which the location of the extinguishing method is economically more expedient for volume. Namely, if the size of the room is 6 times and more exceeds the conditionally dedicated volume occupied by the equipment to be protected by the APT, then in this case the local extinguishing method is cost-effective in volume.

Gas fire extinguishing substance.

The choice of gas fire extinguishing agent should be made only on the basis of a feasibility study. All other parameters, including the efficiency and toxicity of GOTS cannot be considered as determining for a number of reasons.
Any of the permitted to use is quite efficient and the fire will be eliminated if a regulatory concentration will be created in the protected amount.
An exception to this rule is the extinguishing of materials prone to degeneration. Studies conducted in FGU VNIIPO EMERCOM of Russia under the direction of A.L. Chibisov showed that the complete cessation of burning (fiery and decline) is possible only when the three-time carbon dioxide is submitted. Such a number of carbon dioxide reduces the concentration of oxygen in the burning zone below 2.5% vol.

According to regulatory requirements in Russia (NPB 88-2001), it is forbidden to produce a gas extinguishing agent into the premises if people are located there. And this restriction is correct. The causes of people's death in fire shows that more than 70% of the deaths of people are fatal outcome due to the poisoning of combustion products.

The cost of each of the GOTS is significantly different from each other. At the same time, knowing only the price of 1 kg of gas fire extinguishing agent cannot be estimated the cost of fire protection 1 m 3 volume. Unambiguously, it is only possible to say that protection of 1 m 3 of volume with GOTV N 2, AR and "Inergen" at a cost of 1.5 times and more expensive than the remaining gas fire extinguishing substances. This is due to the fact that the listed GOTOS is stored in gas fire extinguishing modules in a gaseous state, which requires a large number of modules.

UGPs are two types: centralized and modular. The selection of the type of gas fire extinguishing type depends on the number of protected premises on one object, secondly, from the availability of a free space in which the fire extinguishing station can be placed.

When protecting on one object of 3 and more rooms, located apart at a distance of 10 m, from an economic point of view, centralized UGP is preferable. Moreover, the cost of the protected volume decreases with increasing the number of rooms protected from one fire extinguishing station.

At the same time, centralized UGP compared to modular, has a number of shortcomings, namely: the need to perform a large number of requirements of the NPB 88-2001 to the fire extinguishing station; The need for laying on the building of pipelines from fire extinguishing station to protected premises.

Gas fire extinguishing modules and batteries.

Gas fire extinguishing modules (IHL) and batteries are the main element of the installation of gas fire extinguishing. They are intended for storing and producing GOTV to the protected room.
IHP consists of a cylinder and a locking device (s). Batteries, as a rule, consist of 2 and more gas fire extinguishing modules, combined with a single collector of factory execution. Therefore, all the requirements that are presented to the IHL are similar for both batteries.
Depending on the gas extinguishing agent used in the UGP of the Gas Flavoring Substance, must meet the following requirements.
IHL, reflected by chladones of all brands should ensure the release time of GOTV not exceeding 10 s.
The design of gas fire extinguishing modules, filled with 2, N 2, AR and "inergen", should ensure the release time of the GOTV not exceeding 60 s.
In the process of operation, the IHP should ensure the control of the mass of the payroll.

Control of the mass of refrigeration 125, chladone 318c, chladone 227ea, N 2, Ar and "inergen" is carried out using a pressure gauge. With a decrease in the pressure of the gas-displacer in the cylinders with the above chladones above 10%, and N 2, Ar and "inergen" by 5% of the nominal IHP should be sent for repair. The difference in pressure loss is caused by the following factors:

With a decrease in the pressure of the gas-displacer, the mass of chladone in the vapor phase is partially lost. However, this loss is not more than 0.2% of the initial reflection of the mass of the chladone. Therefore, a pressure limit equal to 10% is caused by an increase in the release time of the GOTOS from the UGP as a result of a decrease in the initial pressure, which is determined based on the hydraulic calculation of the gas fire extinguishing installation.

N 2, Ar and "Inergen" are stored in gas fire extinguishing modules In a compressed state. Therefore, the decrease in pressure by 5% of the initial value is an indirect method of losing the mass of gotat on the same value.

Monitoring the loss of the mass of GOTV, displaced from the module under pressure from its own saturated vapor (chladone 23 and CO 2), should be carried out by a direct method. Those. A gas fire extinguishing module, fastened with chladone 23 or CO 2, during operation should be installed on a weight device. At the same time, the weight device should ensure control of the loss of the mass of the gas fire extinguishing substance, and not the total mass of the step and module, with an accuracy of 5%.

The presence of such a weight device provides that the module is installed or suspended on a strong elastic element, the movement of which changes the properties of the strain sensor. The electronic device reacts to these changes, which gives an alarm signal when changing the parameters of the strain sensor above the installed threshold. The main drawbacks of the tensometric device are to ensure the free movement of the cylinder on a solid metal-mounted design, as well as negative influence External factors - connective pipelines, periodic jokes and vibrations during operation, etc. increase the metal consumption and product dimensions, problems with installation increase.
In MPTU modules 150-50-12, MPTU 150-100-12 applied a high-tech method for monitoring the preservation of GOTV. The electronic mass control device (UKM) is built directly into the locking device (PC) of the module.

All information (Massop, calibration date, service date) is saved in the MCM storage device and can be displayed on the computer. For visual control, the module's CPU is equipped with an LED, which gives signals about normal operation, reducing the mass of GOTS by 5% or more or malfunction to the UKM. Moreover, the cost of the proposed gas control device in the module is much smaller than the cost of a strain gauge weight device with a control device.

Isothermal module for carbon liquid dioxide (MIJO).

Miscellates consists of a horizontal tank for storage CO 2, a lock-starting device, the amounts of quantity control and pressure control devices, refrigeration units and control shield. Modules are intended to protect the premises of up to 15 thousand. 3. Maximum capacity mission - 25t CO 2. The module is stored, as a rule, a working and backup reserve CO 2.

An additional advantage is the possibility of its installation outside the building (under a canopy), which allows you to significantly save production areas. In heated room or warm boxing, only mpg control devices and Distribution devices UGP are installed (if available).

IHL with a capacity of cylinders up to 100 liters, depending on the type of combustible load and the filled GOTOS allow to protect the room with a volume of not more than 160 m 3. To protect the premises of the larger volume requires installation of 2 or more modules.
A technical and economic comparison showed that in order to protect the premises of more than 1500 m 3 in the UGP, it is more expedient to use isothermal modules for liquid carbon dioxide (mew).

Nozzles are intended for uniform distribution of GOTV to the volume of protected room.
The placement of nozzles in the protective room is carried out in accordance with the factory of the manufacturer. The number and area of \u200b\u200bthe outlet openings of the nozzles is determined by the hydraulic calculation, taking into account the flow rate and the map of the dispenser specified in the technical documentation for the nozzle.
The distance from the nozzles to the ceiling (overlap, suspended ceiling) should not exceed 0.5 m when using all GOTS, with the exception of N 2.

Pipe layout.

The layout of pipelines in the protective room, as a rule, should be symmetrical with an equal removal of nozzles from the main pipeline.
Installation pipelines are made of metal pipes. The pressure in the installation pipelines and diameters is determined by the hydraulic calculation according to the methods agreed in the prescribed manner. Pipelines must withstand pressure when tested for strength and tightness of at least 1.25 rract.
When used as a GOT ROOM, the total volume of pipelines, including a collector, should not exceed 80% of the refrigerant phase of the refrigerant in the installation.

Tracing of distribution pipelines of installations that use chladone should be carried out only in the horizontal plane.

When designing centralized installations using chladones, attention should be paid to the following points:

• connect the main piping of the room with a maximum volume closer to the battery with GOTS;
• with a serial connection to the station collector with the main and reserve reserve, the most remote from the protected premises should be the main supply from the condition of the maximum reference output from all cylinders.

The right choice of gas fire extinguishing installation UGP depends on many factors. Therefore, the purpose of this work is to show the main criteria affecting the optimal choice of UGP and the principle of its hydraulic calculation.
Below are the main factors affecting the optimal choice of UGP. First, the type of combustible load in the protective room (archives, focusing, radio-electronic equipment, technological equipment, etc.). Secondly, the magnitude of the protected volume and its leaks. Third, the type of gas fire extinguishing agents of GOTV. In the fourth, the type of equipment in which the GOTS must be stored. Fifth, Type of UGP: centralized or modular. The last factor can only take place if you need fire protection two or more rooms on one object. Therefore, we consider the mutual influence of only four above the listed factors. Those. In the assumption that the facility requires fire protection only one room.

Of course, the right choice of UGP should be based on optimal technical and economic indicators.
It should be especially noted that any of the permitted GOTOS liquidates the fire regardless of the type of combustible material, but only when creating a regulatory extinguishing concentration in the protected volume.

The mutual influence of the factors listed above on the technical and economic parameters of the UGP will be assessed from the condition that the following GOTV: Cladon 125, reference 318c, reference 227EA, reference 23, CO 2, N 2, AR and mixture (N 2, AR and CO 2), having a trademark "Inergen".

According to the method of storage and methods of controlling the GOTV in the MMP gas fire extinguishing modules, all gas fire extinguishes can be divided into three groups.

The 1st group includes chladone 125, reference 318c and reference 227ea. These chladones are stored in the IHL in a liquefied form under pressure of the gas-displacer, most often - nitrogen. Modules with listed chladones, as a rule, have a working pressure not exceeding 6.4 MPa. The control of the amount of chladone during the operation of the installation is carried out according to the pressure gauge installed on the IHL.

Claudone 23 and CO 2 make up the 2nd group. They are also stored in liquefied form, but they are displaced from the IHL under pressure from their own saturated vapors. The operating pressure of modules with the listed GOTS must have a working pressure of at least 14.7 MPa. During operation, the modules must be installed on weighing devices that provide continuous control of the mass of chladone 23 or CO 2.

The 3rd group includes N 2, AR and inergen. Data from GOTOS is stored in the IHL in a gaseous state. Further, when we evaluate the advantages and disadvantages of GOTS from this group, only nitrogen will be considered. This is due to the fact that N2 is the most efficient GOTV (has the smallest fire extinguishing concentration and at the same time the smallest cost). The mass control of the 3rd group's mass is carried out on a pressure gauge. N 2, AR or inergen are stored in modules at a pressure of 14.7 MPa and more.

Gas fire extinguishing modules, as a rule, have a container of cylinders not exceeding 100 liters. Modules with a capacity of more than 100 liters according to PB 10-115 are subject to registration in the Gosgortkhnadzor of Russia, which entails a sufficiently large number of restrictions on their use in accordance with the indicated rules.

The exceptions are isothermal modules for carbon liquid dioxide mobility with a capacity from 3.0 to 25.0 m3. These modules are designed and manufactured for storage in gas fire extinguishing systems of carbon dioxide in quantities exceeding 2500 kg or more. Miasses are equipped with refrigerator units and heating elements, which allows maintenance of pressure in an isothermal tank in the range of 2.0 - 2.1 MPa at ambient temperature from minus 40 to plus 50 degrees. FROM.

Consider on the examples, as each of the 4 factors affect the technical and economic indicators of the UGP. The mass of GOTS was calculated according to the method described in the NPB 88-2001.

Example 1. It is required to protect radio-electronic equipment indoors of 60 m 3. The room is conditional hermetic. Those. K2 \u003d 0. The results of the calculation in the table. one.

Table 1

Economic substantiation of the table in specific figures has a certain difficulty. This is due to the fact that the cost of equipment and gotto from companies - producers and suppliers has a different cost. However, there is a common trend in the fact that the cost of the gas fire extinguishing module increases with an increase in the capacity of the cylinder. The cost of 1 kg of CO 2 and 1 m 3 N 2 is close at a price and two orders of magnitude less than the cost of chladone. Table analysis. 1 shows that the cost of UGP with chladone 125 and CO 2 is comparable in magnitude. Despite the significantly higher cost of chladone 125 compared with carbon dioxide. The total price of refrigerant 125 - IHP with a capacity of 40 liters with a capacity of 40 liters will be comparable or even somewhat lower than the carbon dioxide set - IHP with a cylinder 80 L - weight device. It is uniquely to state a significantly greater value of UGP with nitrogen compared to the two previously considered options. Because 2 modules are required with a maximum volume. It will take more space to accommodate 2 modules in the room and, of course, the cost of 2 modules with a volume of 100 liters will always be larger than the module with a volume of 80 liters with a weight device, which, as a rule, 4 - 5 times the price is less than the module itself.

Example 2. The parameters of the room are similar to example 1, but it is required to protect non-radio-electronic equipment, but an archive. The results of the calculation is similar to the 1st example in Table. 2 We will bring in table. one.

table 2

Based on the analysis of Table. 2 can be unambiguously to say, and in this case, UGP with nitrogen at a cost is significantly higher than gas fire extinguishing installations with chladone 125 and carbon dioxide. But in contrast to the 1st example, in this case, it can be more clearly to note that the lowest cost has a treaty with carbon dioxide. Because With a relatively small difference in the cost between the IHL with a cylinder, a capacity of 80 l and 100 liters, the price of 56 kg of chladone 125 significantly exceeds the cost of the weight device.

Similar dependencies will be traced if the volume of the protected room is increasing and / or its leaks increases. Because All this causes a general increase in the number of any kind of got.

Thus, only on the basis of 2 examples, it can be seen that choosing the optimal UGP for fire protection of the room can be selected only after consideration, at least two options with various types of GOTS.

However, there are exceptions when the UGP with optimal technical and economic parameters cannot be applied due to certain restrictions imposed on gas fire extinguishes.

Such restrictions, first of all, refers to the protection of particularly important objects in the seismic zone (for example, objects of nuclear power, etc.), where installation of modules in seismic resistant frames is required. In this case, the use of chladone 23 and carbon dioxide is excluded, since modules with these GOTS should be installed on weight devices that exclude their rigid fastening.

For fire protection Premises with constantly present personnel (air traffic tracks, halls with nuclear power plants, etc.) are presented to the toxicity of GOTS. In this case, the use of carbon dioxide is excluded, since the volumeting fire extinguishing concentration of carbon dioxide in the air is fatal for humans.

When protecting the volumes of more than 2000 m 3 from an economic point of view, the use of carbon dioxide, refilled in a mission, compared with all the rest of GOTS, is the use of carbon dioxide.

After conducting a feasibility study, the number of GOTV, which is necessary to eliminate fire and a preliminary amount of IHP becomes a known.

Nozzles must be installed in accordance with the scrawl cards specified in the technical documentation of the manufacturer of the manufacturer of the nozzles. The distance from the nozzles to the ceiling (overlapping, suspended ceiling) should not exceed 0.5 m when using all GOTV, with the exception of N 2.

Pipe layout, as a rule, should be symmetrical. Those. Nozzles must be equal to the main pipeline. In this case, the consumption of retreats through all the nozzles will be the same, which will ensure the creation of a uniform fire extinguishing concentration in the protected amount. Typical examples of symmetric pipe wiring are shown on fig. 1 and 2..

When designing the pipe wiring, it should also take into account the correct compound of removal pipelines (rows, taps) from the main pipeline.

Conducting compound is possible only under the condition when the consumption of G1 and G2 is equal in size (Fig. 3).

If G1? G2, then the opposite compounds of rows and taps with a main pipeline must be made in the direction of movement of the move at a distance L, exceeding 10 * d, as shown in Fig. 4. Where d is the inner diameter of the main pipeline.

No restrictions are superimposed on the spatial connection of pipes during the design of pipe wiring, there are no restrictions when applying GOTV, belonging to the 2nd and 3rd groups. And for pipe wiring UGP with the 1st group, there are a number of restrictions. This is caused by the following:

When reducing the chladone 125, the refrigeration of 318c or chladone 227ea in the IHP nitrogen to the desired pressure, partially nitrogen dissolves in the listed chladones. Moreover, the amount of dissolved nitrogen in chladones is proportional to pressure pressure.

After opening the shut-off-starting device, the CPU of the gas fire extinguishing module under the pressure of the gas-displacer pressure with a partially dissolved nitrogen on the pipe wiring is received to nozzles and through them it goes into the protected volume. In this case, the pressure in the system (modules - pipe wiring) decreases as a result of the expansion of the volume occupied by nitrogen in the process of displacing the refrigeration, and the hydraulic resistance of the pipe wiring. A partial selection of nitrogen from the liquid chladone phase occurs and a two-phase medium is formed (a mixture of the liquid chladone phase is nitrogen gaseous). Therefore, a number of restrictions are superimposed on the pipe wiring of the UGP using the 1st group. The main meaning of these restrictions is aimed at preventing the separation of the two-phase medium inside the pipe wiring.

When designing and installing, all pipe wiring connections UGP should be performed as shown in Fig. 5A, 5B and 5V

and it is forbidden to perform in the species shown in Fig. 6a, 6b, 6c. In the drawings, the arrows shows the direction of the flow of the GOTO through the pipes.

In the process of designing an UGP in axonometric form, a pipe wiring diagram is performed, the length of the pipes, the number of nozzles and their high-altitude marks. To determine the internal diameter of the pipes and the total area of \u200b\u200bthe outlet holes of each nozzle, it is necessary to perform hydraulic calculation of the gas fire extinguishing installation.

Control automatic installations Gas fire extinguishing

When choosing an optimal control of automatic gas fire extinguishing installations, it is necessary to be guided by the technical requirements, features and functional features of protected objects.

The main schemes for building gas fire extinguishing control systems:

• autonomous gas exhaust control system;
• decentralized gas fire extinguishing control system;
• centralized gas extinguishing system.

Other options are derived from these typical schemes.

To protect local (separately worthy) rooms per one, two and three directions of gas fire extinguishing, as a rule, the use of autonomous gas fire extinguishing systems is justified (Fig. 1). The autonomous gas extinguishing station is located directly at the entrance to the protected room and controls both threshold fire detectors, light or sound notification and remote and automatic starting of the gas fire extinguishing unit (GPT). The number of possible directions of gas fire extinguishing on this scheme can reach from one to seven. All signals from the autonomous gas fire extinguishing station come directly to the Central Dispatch District on the station's output panel.

Fig. one.Autonomous Gas Faivory Control Installations

The second typical scheme is a diagram of a decentralized gas control control, presented in Fig. 2. In this case, the autonomous gas extinguishing station is embedded in an existing and existing comprehensive object security system or newly designed. Signals from an autonomous gas extinguishing station come to the address blocks and control modules, which then transmit information to the central dispatch post on the central fire alarm station. A feature of the decentralized gas fire management control is that upon failure of individual elements. complex system Safety of the object The autonomous gas fire extinguishing station remains in operation. This system allows you to embed into your system any number of gas fire extinguishing directions, which are limited only. technical capabilities The station itself fire alarm.

Fig. 2.Decentralized gas fire extinguishing control into several directions

The third scheme is a diagram of a centralized control of gas fire extinguishing systems (Fig. 3). This system is applied in the case when the requirements for fire safety are priorities. The fire alarm system includes address and analog sensors that allow you to control the protected space with minimal errors and prevent false responses. False responses of the fire system occur due to pollution of ventilation systems, supply exhaust ventilation (smoke from the street), strong wind, etc. Warning false positives in address and Analog Systems It is carried out by controlling the dust of the sensors.

Fig. 3. Centralized gas fire extinguishing management into several directions

The signal from address-analog fire detectors enters the central station of fire alarm, after which the data processed through the address modules and blocks come to autonomous system Gas fire control. Each sensor group is logically tied to its gas fire extinguishing direction. The centralized gas extinguishing system is calculated only on the number of station addresses. Take, for example, a station with 126 addresses (single-stove). Calculate the number of necessary addresses to maximize the premises. Control modules - automatic / manual, gas is served and a malfunction is 3 addresses plus the number of sensors indoors: 3 - on the ceiling, 3 - per ceiling, 3 - under the floor (9 pcs.). We get 12 addresses to the direction. For a station with 126 addresses, these are 10 directions plus additional addresses for managing engineering systems.

The use of centralized gas fire extinguishing management leads to the rise in the cost of the system, but significantly increases its reliability, makes it possible to analyze the situation (control of dusty of sensors), and also reduces the cost level of maintenance and operation. The need to install a centralized (decentralized) system occurs with additional management of engineering systems.

In some cases, in place of the modular gas fire extinguishing unit, fire extinguishing stations are used in the gas fire extinguishing systems of the centralized and decentralized type. Their installation depends on the area and the specifics of the protected room. In fig. 4 shows the system of centralized control of gas fire extinguishing with a flame station (OGS).

Fig. four.Centralized gas fire extinguishing control of several directions with a fire

The choice of the optimal version of the gas fire extinguishing option depends on the large number of source data. An attempt to summarize the most significant parameters of gas fire extinguishing systems and installations is presented in Fig. five.

Fig. five.Select the optimal option for installing gas fire extinguishing software

One of the features of AGPT systems automatically is the use of address-analog and threshold fire detectors as devices recording a fire when the fire extinguishing system is launched, i.e. Release of fire extinguishing agent. And here it should be noted that from the reliability of the fire detector, one of the cheapest elements of the fire alarm system and fire extinguishing system, depend on the efficiency of the entire expensive complex of fire automation and, therefore, the fate of the protected object! At the same time, the fire detector must meet two basic requirements: the early definition of fire and the absence of false positives. What depends on the reliability of the fire detector as electronic device? From the level of development, quality of element base, assembly technology and final testing. The consumer is very difficult to understand all the variety of detectors presented today in the market. Therefore, many are focused on the price and availability of a certificate, although, unfortunately, it is not today a guarantee of quality. Only the units of fire detector manufacturers openly publish the figures of the refusal, for example, according to the Moscow manufacturer of Systems Sensor Fair Detectors, its products are less than 0.04% (4 products per 100 thousand). This is definitely a good indicator and the result of multistage testing of each product.

Of course, only the address-analog system allows the customer to be absolutely confident in the performance of all its elements: smoke and heat sensors controlling the protected room are constantly polled by the fire management station. The device monitors the state of the loop and its components, in the case of a decrease in the sensor sensitivity, the station automatically compensates for it by installing the corresponding threshold. But when using chaasadres (threshold) systems, the sensor failure is not determined, and the loss of its sensitivity is not tracked. It is believed that the system is in working condition, but in reality the fire management station in the event of a real fire will not work accordingly. Therefore, when installing automatic gas fire extinguishing systems, it is preferable to use targeted-analog systems. Their relatively high cost is compensated by unconditional reliability and qualitative decrease in the risk of fire.

In general, the working draft RP of the gas fire extinguishing unit consists of an explanatory note, the technological part, the electrical part (in this paper is not considered), the specifications of equipment and materials and the estimation (at the request of the customer).

Explanatory note

The explanatory note includes the following sections.

Technological part.

1. • 
     In the subsection, the technological part is given a brief description of the main composite elements UGP The type of selected gas fire extinguishing agent of GOTV and the gas-displacer is indicated, if available. For chladone and mixture of gas fire extinguishing substances, a fire safety certificate number is reported. The type of IHL gas fire extinguishing modules (batteries) selected for the storage of the gas fire extinguishing agent, the fire safety certificate number is given. A brief description of the main elements of the module (battery), the method of controlling the mass of GOTS The parameters of the MHP electrical start (battery) are given.
1. General Provisions.

The General Provisions section provides the name of the object for which the working draft UGP was completed, and the rationale for its implementation. Regulatory and technical documents are given, on the basis of which project documentation has been completed.
The list of basic regulatory documents used in designing UGP is given below. NPB 110-99
NPB 88-2001 with meas. №1
Due to the fact that there is a permanent job on improving regulatory documents, designers must constantly adjust this list.

2. Purpose.

This section indicates how to install gas fire extinguishing and the functions performed.

3. Brief description of the protected object.

In this section generally given a brief description of Premises to be protected UGP, their geometrical dimensions (volume). It is reported on the presence of raised floors and ceilings with a volumetric method of fire extinguishing or the configuration of the object and its location with local in volume. Information about the maximum and minimum temperature and humidity of the air, the presence and characteristics of the ventilation and air conditioning system, the presence of constantly open opening and extremely permissible pressures in protected areas are indicated. Data on the main types of fire load, the categories of protected premises and zone classes are given.

4. Basic design solutions. This section has two subsections.

It is reported on the selected type of nozzles for the uniform distribution of the gas extinguishing agent in the protected volume and the adopted standards of release of the estimated mass of GOTV.

For centralized installation, the type of distribution devices and the fire safety certificate number is given.

Formulas that are used to calculate the mass of the gas fire extinguishing agent of the UGP, and the numerical values \u200b\u200bused in the calculations are the numerical values \u200b\u200bof the main values: the adopted regulatory fire extinguishes for each protected volume, the density of the gas phase and the residue of the GOTOS in modules (batteries), the coefficient that takes into account the losses of the gas fire extinguishing substance From modules (batteries), the residue of GOTV in the module (batteries), the height of the protected room above sea level, the total area of \u200b\u200bconstantly open openings, the height of the room and the filing time of the GOTS.

The time calculation of the evacuation time of people from premises, which are protected by gas fire extinguishing installations and indicates the time of stopping the ventilation equipment, the closure of fire-graded valves, air dampers, etc. (if available). At the time of evacuation of people from the room or stopping the ventilation equipment, the closure of fire-graded valves, air dampers, etc. Less than 10 s Recommended Time Delay Time to receive 10 s. If all or one of the limiting parameters, namely, the estimated time of the evacuation of people, the time of stopping the ventilation equipment, the closure of fire-graded valves, air dampers, etc. exceeds 10 s, then the delay time of the release of GOTS must be taken to a greater value or close to it, but in the most side. It is not recommended to artificially increase the delay time of the release of GOTOS for the following reasons. First, UGPs are designed to eliminate the initial stage of the fire, when the destruction of the enclosing structures and, above all, the windows. The emergence of additional openings as a result of the destruction of enclosing structures with a developed fire, not taken into account when calculating the required amount of GOTS, will not allow the normative fire extinguishing concentration of the gas fire extinguishing agent in the room after the operation of the UGP. Secondly, an artificial increase in free combustion time leads to unreasonably large material losses.

In the same subsection, according to the results of calculations of the maximum permissible pressures, carried out by the requirements of paragraph 6 of GOST R 12.3.047-98, it is reported that it is necessary to establish additional openings in the protected premises to reset the pressure after the assignment of the UGP or not.

1. • Electrical part.

     In this subsection it is reported on the basis of what principles, fire detectors are selected, their types and numbers of fire safety certificates are given. The type of receiving and control and control instrument and the number of its fire safety certificate is indicated. A brief description of the basic functions that performs the device.

2. Principle of installation.

   This section has 4 subsections in which it is described: "Automatic Mode is enabled";

   • mode "Automation is disabled";
   • remote Start;
   • local start.
3. Power supply.

   This section indicates which category of power reliability includes an automatic installation of gas fire extinguishing and in what diagram the instruments and equipment included in the installation should be carried out.

4. Composition and placement of elements.

   This section has two subsections.

   • Technological part.

     This subsection provides a list of the main elements, of which the technological part of the automatic installation of gas fire extinguishing, places and requirements for their installation.

   • Electrical part.

     This subsection provides a list of the main elements of the electrical part of the automatic gas fire extinguishing installation. Givens on their installation. The brands of cables, wires and conditions for their gasket are reported.

5. Professional and qualifying composition of persons working at the facility for maintenance and operation of the automatic fire extinguishing installation.

The composition of this section includes the requirements for personnel qualifications and its number when servicing the projected automatic gas fire extinguishing installation.

1. Activities for labor protection and safe operation.

   In this section, regulatory documents are reported, on the basis of which assembly and commissioning works and maintenance of automatic installation of gas fire extinguishing. Requirements for persons allowed to maintain automatic gas fire extinguishing installation.

The activities that need to be performed after the operation is described in the event of a fire.

British standards requirements.

It is known that there are significant differences between Russian and European requirements. They are due to national peculiarities, geographical location and climatic conditions, level economic Development countries. However, the main provisions that determine the efficiency of the system should coincide. The following are comments to the British standard BS 7273-1: 2006 Part 1 on the gas volumetric extinguishing systems with electrical activation.

British standard BS 7273-1: 2006 Replaced Standard BS 7273-1: 2000. Fundamental differences of the new standard from previous version Marked in its preface.

• BS 7273-1: 2006 is a separate document, but in it (in contrast to the operating NPB 88-2001 *), references to the regulatory documents, together with which it should be used. These are the following standards:
• BS 1635 "Recommendations for graphic symbols and abbreviations for drawings of fire protection systems";
• BS 5306-4 "Equipment and installation of fire extinguishing systems" - part 4: "Technical requirements for systems with carbon dioxide";
• BS 5839-1: 2002 concerning fire detection systems and alerts for buildings. Part 1: "Norms and rules for the design, installation and maintenance of systems";
• BS 6266 "Norms and rules for protection against fire equipment installations";
• BS ISO 14520 (all parts), "Gas fire extinguishing systems";
• BS EN 12094-1, "Stationary Fire Systems - Components of Fire Extinguishing Gas Systems" - Part 1: "Requirements and Test Methods of Automatic Controls".

Terminology

Definitions of all major terms are taken from BS 5839-1, BS EN 12094-1 standards, in the BS 7273 standard, only the few listed terms are defined.

• Automatic / manual mode switch and manual only - a system for transfering a system from an automatic or manual activation mode to manual activation mode (with a switch, as explained in the standard, can be made in the form of a manual switch in the control device or in other devices, or in the form of Separate door block, but in any case, switching system activation mode with automatic / manual on only manual or back) is provided:
  • automatic mode (in relation to the fire extinguishing system) is a functioning mode in which the system is initiated without manual intervention;
  • manual mode - the one in which the system can only be initiated by manual control.
• The protected area is an area located under the protection of the fire extinguishing system.
• The coincidence is the logic of the system in which the output signal is supplied in the presence of at least two independent input signals that are simultaneously present in the system. For example, the output signal to activate fire extinguishing is formed only after the fire is detected by one detector and, at least, when another independent detector of the same protected zone confirmed the presence of a fire.
• The control device is a device that performs all the functions necessary to control the fire extinguishing system (in the standard it specifies that this device can be made as a separate module or as component automatic fire alarm system and fire extinguishing).

Design system

The standard also notes that the requirements for the protected area must be established by the designer during consultations with the client and, as a rule, by architect, specialists of contractors engaged in the installation of the fire alarm system and the automatic fire extinguishing system, fire safety experts, experts of insurance companies, A responsible person from the Office of Health, as well as representatives of any other interested departments. In addition, it is necessary to pre-schedule actions that, in the event of a fire, should be taken to ensure the safety of persons in the territory and the effective functioning of the fire extinguishing system. This kind of action should be discussed at the design stage and implement in the proposed system.

The system project must also comply with the standards of BS 5839-1, BS 5306-1 and BS ISO 14520. Based on the data obtained during the consultation, the designer is obliged to prepare documents containing not only a detailed description of the design solution, but, for example, and simply graphic Representation of the sequence of actions leading to the launch of the extinguishing agent.

System functioning

In accordance with the specified standard, the fire extinguishing system operation algorithm should be formed, which is given in graphical form. Annex to this standard provides an example of such an algorithm. As a rule, in order to avoid unwanted gas startup in the case of an automatic system operation mode, the sequence of events should assume a fire definition at the same time with two separate detectors.

The activation of the first detector should, at least, lead to an indication of the "Fire" mode in the fire alarm system and the inclusion of alert within the protected area.

The gas release from the extinguishing system should be monitored and indicated by the control device. To control the gas start, the pressure or gas flow sensor should be used, located in such a way as to control its release from any cylinder in the system. For example, in the presence of conjugate cylinders, gas production should be monitored from any container to the central pipeline.

The interruption of the communication between the fire alarm system and any part of the fire extinguishing control device should not affect the operation of fire sensors or to respond to the fire alarm system.

Requirement for improving performance

The fire alarm system and alert must be designed in such a way that in the event of a single damage to the loop (cliff or short circuit), it detected a fire on the protected area and, at least, left the possibility of switching on fire extinguishing manually. That is, if the system is designed in such a way that the maximum system controlled by one detector is x m 2, then with a single loop failure, each workable fire sensor must ensure control of the area to the maximum 2x m 2, the sensors must be distributed via the protected area evenly.

This condition can be performed, for example, by using two radial loops or one ring loop with short-circuit protection devices.

Fig. one.System with two parallel radial loops

Indeed, when climbing or even with a short circuit of one of two radial loops, the second loop remains in a working condition. In this case, the detectors should ensure control of the entire area protected by each loop separately. (Fig. 2)

Fig. 2.Alignment of detectors "couples"

More high level Operations are achieved when using ring loops in address and address-analog systems with short circuit insulators. In this case, when the ring loop is cut, it is automatically converted into two radial, the breakdown location is localized and all sensors remain in the working condition, which saves the system functioning in automatic mode. With a short circuit of the ring loop, only devices are disconnected between two adjacent short circuit insulators, and therefore most of the sensors and other devices also remain workable.

Fig. 3. Open ring loop

Fig. four.Ring Circuit

A short circuit insulator is usually two symmetrically turned electronic keys, between which the fire sensor is located. Structurally, a short-circuit insulator can be built into the database, which has two additional contacts (input and output via a plus), or embedded directly into the sensor, in manual and linear fire detectors and in functional modules. If necessary, a short circuit insulator, made in the form of a separate module, can be used.

Fig. five.Short-circuit insulator in the sensor database

Obviously, the system often used in Russia with one "two-step" loop does not meet this requirement. When breaking such a plume, a certain part of the area of \u200b\u200bprotected area remains without control, and during the short circuit there is no control completely. The "Fault" signal is formed, but before troubleshooting the "Fire" signal is not formed by any sensor, which does not allow you to turn on the fire extinguishing manually.

Protection against false response

Electromagnetic fields from radio transmission devices may cause false signals in fire alarm systems and lead to activation of the processes of electrical output of gas outlet from fire extinguishing systems. Almost all buildings use such equipment as portable radio stations and cell Phones, near or on the building, basic transceiver stations simultaneously several cellular operators can be located. In such cases, measures must be taken to exclude the risk of random gas emission due to the effects of electromagnetic radiation. Similar problems may occur if the system is installed in places of high field strengths - for example, near airports or radio transmission stations.

It should be noted that a significant increase in the level of electromagnetic interference in recent years caused by the use of mobile communications has led to an increase in European requirements for fire sensors in this part. According to European standards, the fire detector must withstand the effect of electromagnetic interference with the tension of 10 V / m in the ranges of 0.03-1000 MHz and 1-2 GHz, and 30 V / m intensity in the cellular ranges of 415-466 MHz and 890-960 MHz, and with sinusoidal and impulse modulation (Table 1).

Table 1. Requirements LPCB and VDS on sensor stability to electromagnetic interference.

*) Pulse modulation: frequency 1 Hz, dioxide 2 (0.5 C - incl., 0.5 C - pause).

European requirements correspond to modern operating conditions and are several times higher than the requirements even at the highest (4th degree) of stiffness on NPB 57-97 "Instruments and equipment of automatic fire extinguishing and fire alarm installations. Noise immunity and interference. General technical requirements. Test methods" (Table 2). In addition, according to NPB 57-97, tests are carried out at maximum frequencies of up to 500 MHz, i.e. 4 times smaller compared to European tests, although the "effectiveness" of the impact of interference to the fire detector with increasing frequency usually increases.

Moreover, according to the requirements of the NPB 88-2001 * clause 12.11, to control automatic fire extinguishing installations, fire detectors must be resistant to the effects of electromagnetic fields with a degree of rigidity just not lower than the second.

Table 2.Requirements for stability of detectors to electromagnetic interference on NPB 57-97

Ranges of frequency and levels of electromagnetic fields during tests for NPB 57-97 do not take into account the presence of several cellular systems with a huge number of base stations and mobile phones, nor increasing the power and number of radio and television stations, or other similar interference. An integral part of the urban landscape was the transceiver antennas of base stations, which are placed on different buildings (Fig. 6). In zones where there are no buildings of the required height, the antennas are installed on various masts. Usually on one object there is a large number of antennas of several cellular operators, which increases the level of electromagnetic interference several times.

In addition, according to the European standard EN 54-7 to smoke sensors, tests are required for these devices:
- at moisture - first at a constant temperature of +40 ° C and a relative humidity of 93% for 4 days, then with a cyclic temperature change of 12 hours at +25 ° C and 12 hours - at +55 ° C, and with relative humidity at least 93% for another 4 days;
- corrosion tests in the atmosphere of SO 2 gas for 21 days, etc.
It becomes clear why on European requirements the signal from two pi is used only to enable fire extinguishing in automatic mode, and not always, as will be indicated below.

If the detectors are covered by several protected areas, then the emergence initiation signal in the protected area where fire has been detected, should not lead to a fire extinguishing agent to another protected area, the detection system of which uses the same loop.

The activation of manual fire detectors also should not be in any way to influence the launch of the gas.

Establishing a fact of fire

The fire alarm system must meet the recommendations given in Standard BS 5839-1: 2002 according to the corresponding system category, unless other standards are more applicable, for example, the BS 6266 standard for the protection of electronic equipment installations. Detectors used to manage gas start control by automatic fire extinguishing system must function in coincidence mode (see above).

However, if the danger has such nature at which the system's slowdown reaction associated with the coincidence mode can be fraught with severe consequences, then in this case, the gas start is automatically produced when activated by the first detector. Provided that the likelihood of a false response of the detector and alarm system is low, people cannot be present in the protected zone (for example, spaces over suspended ceilings or under raised floors, control cabinets).

In general, measures should be taken to avoid unforeseen gas emissions due to false response alarm. The coincidence of the operation of two automatic detectors is a method of minimizing the likelihood of a false start, which is essential if the possibility of a false response of one detector.

Fire alarm systems that cannot identify each detector separately must have at least two independent loops in each protected area. In address systems using a coincidence mode, the use of one loop is allowed (provided that the signal for each detector can be identified independently).

Note: In zones protected by traditional nonsense systems, after activating the first detector to 50% of detectors (all other detectors of this loop) are excluded from the match mode, that is, the second detector activated in the same loop is not perceived by the system and cannot confirm the presence of a fire. Address systems Provide the setting control over a signal coming from each detector and after activating the first fire detector, which ensures maximum efficiency of the system through the use of all other detectors in the coincidence mode, to confirm the fire.

For the coincidence mode, signals from two independent detectors should be used; Different signals from the same detector cannot be used, for example, formed by one aspiration smoke detector at high and low sensitivity thresholds.

Type of detector used

The choice of detectors should be made in accordance with the BS 5839-1 standard. In some circumstances, two may take two for earlier fire detection. different principles Detection - for example, optical smoke detectors and ionization smoke detectors. In this case, a uniform distribution of detectors of each type throughout the entire protected area should be ensured. Where the coincidence mode is used, it is usually possible to match the signals from two detectors operating according to the same principle. For example, in some cases, two independent loops are used to achieve coincidence; The number included in each loop of detectors acting on different principlesmust be approximately the same. For example: where four detectors are required to protect the room, and they are represented by two optical smoke detectors and two ionization smoke detectors, each plume should have one optical detector and one ionization detector.

Nevertheless, it is not always necessary to use various physical principles of fire recognition. For example, taking into account the type of expected fire and the required fire detection rate is permissible to use the detectors of the same type.

Detectors must be placed in accordance with the recommendations of the BS 5839-1 standard, according to the required system category. However, when using the coincidence mode, the minimum detector density should be 2 times higher than those recommended in this standard. To protect electronic equipment, the fire detection level must comply with the requirements of the BS 6266 standard.

It is necessary to have the means to quickly identify the location of hidden detectors (behind suspended ceilings, etc.) in "Fire" mode - for example, by using remote indicators.

Management and indication

Switch mode

The mode switching device is automatic / manual and only manual - should provide a change in the mode of operation of the fire extinguishing system, that is, when accessing personnel to a non-serving area. The switch must be given in manual control mode and be equipped with a key that can be removed in any position and should be placed near the main entrance to the protected zone.

Note 1: The key is intended only for a responsible person.

The key application mode must comply with BS 5306-4 and BS ISO 14520-1 standards, respectively.

Note 2: Door lock switches acting during locked doors can be preferable for this purpose - in cases where it is necessary to ensure that at the time of the presence of personnel in the protected zone, the system is in manual control mode.

Manual launch device

The functioning of the manual fire extinguishing device must initiate the gas emission and requires the execution of two separate actions to prevent accidental response. The manual starter must be predominantly yellow and have a designation indicating the function to them. Usually, the manual start button is closed with a lid and two steps are required to activate the system: to push the cover and press the button (Fig. 8).

Fig. eight. The manual start button on the control panel is under yellow lid

Devices for access to which you want to break the glazed cover are undesirable due to the potential hazard for the operator. Manual starter devices should be easily accessible and secure for personnel, while it is necessary to avoid their malicious use. In addition, they must visually differ from the manual fire detectors of the fire alarm system.

Start delay time

A start-up delay device can be built into the system in order to allow the staff to evacuate employees with a protected area before gas start. Since the time delay period depends on the potential speed of spreading fire and evacuation facilities from the protected area, this time should be as shorter as possible and not exceed 30 seconds, unless longer than a long time is provided by the appropriate authority. Turning on the time delay device must be designated by a warning beep signal, audible in the protected area ("pre-warning signal").

Note: A continuous start delay contributes to the further dissemination of the fire and the occurrence of the risk of thermal decomposition products from some extinguishing gases.

If you have a start delay device, the system can also be equipped with an alarm device that needs to be placed near the exit of the protected area. While the button is pressed on the device, the countdown of the prepox should stop. When you stop pressing the system continues to be in alarm state, and the timer must be restarted first.

Emergency lock and reset devices

Alarm devices must be present in the system if it works in automatic mode when people are present in the protected area, unless otherwise specified in consultations with stakeholders. The view of the "pre-warning sound signal" must be changed to control the inclusion of the alarm device, and should also be a visual indication of this mode on the control unit.
In some environments, fire extinguishing reset devices can also be installed. In fig. 9 shows an example of a fire extinguishing system structure.

Fig. nine. Fire extinguishing system structure

Sound and light indication

The visual indication of the status of the system should be provided outside the protected zone and are located at all inputs to the room so that the state of the fire extinguishing system is understandable to the personnel entitled to the protected area:
* Red indicator - "Gas Start";
* Yellow indicator - "Automatic / manual mode";
* Yellow indicator - "manual only" mode.

A clear visual indication of the operation of the fire alarm system within the protected area is to activate the first detector: completing the sound notification recommended in the BS 5839-1 standard, light alarms should flash so that people in the building have been notified about the possibility of starting gas. Light alert must comply with the requirements of the BS 5839-1 standard.

Easeless sound alerts must be supplied at the following stages:

• during the launch period of the gas start;
• at the beginning of the start of gas.

These signals can be identical or two distinguishable signals can be fed. The signal included in the "A" stage must be disabled when the alarm lock is functioning. However, if necessary, it can be replaced during its broadcast signal, easily different from all other signals. The signal included in the "B" stage must continue to operate until it is turned off manually.

Power supply, eyeliner

The power supply of the fire extinguishing system must comply with the recommendations given in Standard BS 5839-1: 2002, paragraph 25. The exception is that the words "fire extinguishing system" must be used instead of the words "fire alarm" on the labels describing in BS 5839-1 : 2002, 25.2F.
Food to the fire extinguishing system should be summarized in accordance with the recommendations given in the BS 5839-1: 2002 standard, clause 26 for cables with standard refractory properties.
Note: There is no need to separate fire extinguishing cables from fire alarm cables.

Acceptance and commissioning

After the installation of the fire extinguishing system is completed, clear instructions should be prepared, describing the procedure for its use and intended for the person responsible for using protected premises.
All and responsibility for using the system must be distributed in accordance with BS 5839-1 standards, and the manual and personnel must be familiar with the rules of safe handling of the system.
The user must be provided with a logging log, installation certificate and commissioning, as well as all tests for the work of the fire extinguishing system.
The user must be provided with documentation related to various parts of the equipment (connecting boxes, pipelines), and electrical wiring schemes - that is, all documents relating to the composition of the system, on the items recommended in the standards of BS 5306-4, BS 14520-1, BS 5839- 1 and BS 6266.
The specified schemes and drawings should be prepared in accordance with the BS 1635 standard and as the system changes are updated in order to contain any modifications or additions entered into it.

In conclusion, it can be noted that in the British standard BS 7273-1: 2006 there is no mention of the duplication of fire detectors to increase the reliability of the system. Hard European certification requirements, the work of insurance companies, a high technological level of production of fire sensors, etc. - All this ensures so high reliability that the use of reserve fire detectors lose sense.

Materials used in the preparation of the article:

Gas fire extinguishing. British standards requirements.

Igor Nepchekh, k.t.n.
Technical director of GK fit the PS.

- Magazine “ , 2007