Aspects of selecting a powder fire extinguishing module. Powder fire extinguishing: how to choose the best module? The algorithm of the powder fire extinguishing system

In ancient times, in the Middle Ages, fires were a real scourge, a natural disaster. They destroyed entire neighborhoods, depriving people not only of shelter and work, but also of life. In the past, the only way to fight the fire element was water. It filled the fire. The fire was localized, the damage became less. This method of struggle was not effective, but it was the only one available. Times have changed along with progress in people's lives, new materials have come that, when they ignite, it is simply impossible to extinguish with water.

The development of science made it possible to use new materials, and at the same time made it possible to create new ways to fight fire. One of them is a powder fire extinguishing system.

How to put out fire

Today, there are several ways to extinguish a fire when the inefficiency of using water is obvious:

Most flammable liquids are less dense than water. They cover the surface of the water with a film, so the area grows in case of fire.
Filling with water chemicals, electrical equipment is life-threatening. Trying to deal with a fire will backfire.
Extinguishing fires with water in rooms intended for storing valuables (equipment, books, paintings, etc.) increases the damage. The water element will destroy what the fire could not cope with.

Anhydrous methods

Waterless systems help reduce damage and improve fire fighting efficiency. This category includes:

foam systems.
Steam application.
Gas fire extinguishers.
aerosol methods.
Powder fire extinguishing.

Thanks to this diversity, it became possible to choose the appropriate method of extinguishing a fire corresponding to its characteristics and ignition class.

In order to cope with the fire, it is necessary to stop the supply of oxygen to the source of ignition. Powder fire extinguishing copes with this task, thanks to the properties of metal salts that make up the mixtures.

The quenching process goes like this:

When in contact with burning surfaces, the powder heats up, as a result of which the combustion temperature decreases, since a significant part of the heat is spent on heating the powder.
The heated mixture begins to react. When metal salts decompose, gases are released that do not support fire. An air-powder suspension is formed around the place of combustion. It stops the access of oxygen, which reduces the activity of combustion.
The composition of the powders includes flame retardants.

The automatic powder fire extinguishing system can be used to suppress fires of all classes, regardless of the characteristics of the burning substances or objects (solids and liquids, combustible gases, live electrical equipment, etc.).

Advantages of the powder method

Powder systems are the cheapest.
Simple installation of a powder fire extinguishing system.
Durability. You can store the system for a very long time, the powder retains its properties and effectiveness.
Powder can extinguish almost all materials and objects. It is indispensable in extinguishing fires where the use of water is not possible (ignition of alkali metals, flammable liquids, live electrical equipment).
Versatility. The systems are suitable for extinguishing any fires by class, not excluding specific ones.
Wide range of use powder system when the fire is extinguished at any ambient temperature.
Safety. There is no need to seal the room when using powder systems.

In what cases the powder will not help

Powder systems are effective, but not ideal, they are not suitable in such cases:

Extinguishing substances capable of burning in an oxygen-free environment, smoldering materials.
Powder must be removed immediately from metal surfaces. Metal salts begin to react, which can cause destruction of metal structures.
The powder is difficult to feed through pipelines. This complicates its use in installations with a centralized supply of fire extinguishing material.
Powders render negative impact per person. You can use the system only after in rooms where there are no people.
Cannot be installed automatic systems in buildings with large crowds of people. If such a system is turned on, it can become a source of danger to their lives.

Automation in fire extinguishing

Extinguishing should begin immediately after a fire. In this case, the fire will be quickly localized, and damage is minimized. Automatic systems minimize the time from the moment of ignition to the supply of the fire-fighting mixture. In production shops and warehouses where there are combustible, explosive, chemical dangerous substances fire extinguishing automation is required.

The functions of automatic fire extinguishing installations are:

In alerting people about the start of a fire.
In the localization of the fire.
In maintaining the strength of the building, the integrity of the equipment.

NPB 110-03 establishes the categories of facilities where automatic systems are required to be installed.

Classification of systems according to the method of application are distinguished:

centralized systems.
Modular systems.
Short term modules.

In centralized systems, the fire extinguishing powder is located in a single tank and enters the fire through pipelines. AT modular structures the powder is distributed into separate tanks located in places of possible ignition. Each module is a stand-alone structure.

The command to extinguish the source of fire is given automatically or manually from the place of control of the system. Physical properties powder made it difficult to use in centralized installations. Most of the operating systems have a modular design.

Powder modules have different designs:

With a gas generating element that releases gas at the moment the command is given.
With pre-charged gas.

The quenching process also occurs in different ways:

The air-powder mixture will completely fill the volume of the room (volumetric).
The powder is distributed over surfaces (surface).
The mixture is distributed in the volume of the room and on surfaces, in those places where there is a risk of fire (local).

Premises with automatic powder fire extinguishing systems should be equipped with sound alarms and light displays “Powder! Do not enter!" and "Exit".

Mounting

Equipping the premises with powder fire extinguishing agents is carried out in several stages:

Wiring diagram for automatic powder type fire extinguishing installation

The design of the system is based on the inspection of the premises. The project itself must comply with GOST, SNiP and agreed with the Ministry of Emergency Situations.
Drawing up a budget. The cost of installation depends on the architectural and planning features of the building, the type of fire extinguishing system.
System installation.
Commissioning works.

The number of modules is calculated in accordance with SP 5.13130.2009. The calculation is carried out in four ways:

By area of the room.
By area, locally.
By volume, locally.
According to the cubic capacity of the room.

The appropriate method is selected based on the characteristics of the room and the places of possible ignition. For example, in rooms without shaded areas with ceiling heights corresponding to the height of powder spraying by the module, the simplest calculation is made. The area of the room is divided by the area that one installation can protect. The protected area is specified in technical passport module. The choice of local protection is effective in those rooms where there is a large area, and there are few fire hazardous zones.

The design takes into account the height of the ceilings and the load on structural elements to which the unit will be attached. When the module is triggered, the load on the ceiling structure increases by about 5 times compared to the weight of the installation itself. This load is maintained for approximately 0.2 s. Resistance to a sharply increased load is taken into account when calculating the fire extinguishing system in those rooms where there are dropped ceilings. Ceiling heights must be optimal height spraying, specified in the passport of the device.

False positives

The spraying of the fire-fighting mixture starts after the sensors are triggered or by a signal from the central control panel. Own sensors increase efficiency, but may cause false alarms. This may be due to the following reasons:

Fire alarm failure.
Human factor (unreasonable pressing of the "Control", "Start" buttons).
Electromagnetic pickups.
Starting system malfunction.
Discharge of the autonomous backup battery.

Popular fire extinguishing powder modules

Popular means of powder fire extinguishing systems are modules of the Buran series:

Powder fire extinguishing is well suited for ensuring the fire safety of industrial and warehouse facilities, data centers, server rooms, office and retail premises, etc.

They are not inferior in their effectiveness to other systems, while fire prevention measures with their use will require lower costs.

- almost universal substances. Their use is justified by a wide spectrum of action and high efficiency. The fire-extinguishing properties of powder substances depend on their composition. It is known that the degree of grinding also affects the suppression of combustion processes, but only in some species.

Advantages and disadvantages

Powder fire extinguishing is one of the cheapest ways to fight a fire. Funds can be recharged and reused for their intended purpose. The powder operates at extremely high and low temperatures environment, does not lose its properties even indoors. Easy installation design also contributes to the growing popularity of powder fire extinguishing systems.

Automatic powder fire extinguishing installations can be autonomous. They turn on when a fire is detected, regardless of the control and power systems. This allows you to install and operate them on large areas and in industrial premises increased fire risk. In residential buildings, simple offices, the same systems are often installed.

The risks of damage and failure of correctly installed means are practically eliminated. The absence of excess pressure prevents them from exploding when heated or exposed to other factors. They are resistant to climate change.

From negative aspects note the unsuitability for extinguishing smoldering and self-igniting materials, the limited use in centralized fire extinguishing systems. The negative impact on the human body is also important. Therefore, the evacuation of people is carried out before the start of the work of such fire extinguishing agents.

Systems and installations

The main task of the powder fire extinguishing system is to supply a fire extinguishing agent to the place of ignition. For this, an appropriate system of installations is being developed. Their automation is due to the need to put out the fire faster than the flames and smoke disperse throughout the room and reach other objects.

Most automatic powder type fire extinguishing installations are made in the form of modules. This helps to extinguish fires in short time, and the substance is delivered in a localized and precise manner. Among all types, the following can be distinguished:

Modular installations

In the case of modular powder-type installations there is a powdered substance. The feeder is also located inside the module. Starting modes are electrical, mechanical, combined and thermochemical.

Metal modules are marked in a special way, by designations it is easy to find out the type and capacity of the case, the duration of action, the method of storage, the climatic version, the technical documentation that was used for manufacturing.

One of the types of detectors transmits a signal to the initiating device of the module after the occurrence of factors accompanying a fire. The principles of operation for modules with a certain start mode are different. The next stage is the explosion of the charge and the spraying of the substance.

There is a module type with a different design and storage of fire extinguishing agent. An electrical impulse or heat from the fire acts on the initiating device, and a substance is generated inside the case to extinguish fires.

Modular installations are either included in the general fire extinguishing system, or remain autonomous means. Some types are mounted in false ceilings by analogy with ceiling lights from LED lamps.

Non-standard settings

If the use of a powder fire extinguishing module is unjustified by the conditions, then so-called modular powder fire extinguishing installations are created. They are assembled from separate devices.

The composition of such an installation includes cylinders with gas in a compressed state, pipelines and valves, a vessel for powder, gearboxes and sprinklers. The speed of gas movement through pipelines is measured in terms of the speed of the powder particles. Pipes for aggregate installations are used with a small number of bends and without seams, mainly from steel.

Powder curtains and explosion suppression

Automatic explosion suppression systems are configured in such a way that they are able to create a barrier of powder agents that prevents the spread of fire.

Thus, the flame and detonation wave are extinguished. These systems are conceived for mining companies to increase the safety of mines and workers from coal dust explosions.

Design process and approval in government agencies

The type of system and its functionality. Selection of elements of powder fire extinguishing installations according to parameters and capabilities joint work, they are equipped with additional parts.

Various data are calculated. Therefore, the building type is set first. There are more stringent requirements for building a fire extinguishing system for production shops than for projects and their implementation in small retail outlets.

The design documentation of any fire extinguishing system must be approved by the inspections of the Ministry of Emergency Situations. Only after approval the device is allowed to be installed and used. Systems are checked by responsible persons at the enterprise in order to maintain operability and detect faults in time.

The project usually consists of two parts. In the first, graphic, you can see a schematic representation of the layout of cables and wires, the connection points of devices and devices, the placement of information lines. An individual scheme is developed for each floor.

The text part contains information about system parameters. A kind of explanatory note to the project. The units and devices used must be checked for fire safety in specialized centers of the Ministry of Emergency Situations to obtain a certificate.

Equipment before installation is checked for serviceability and compliance with the specification attached to the project. The organization developing the system must have passports for units, devices, modules, reinforcing elements.

System installation and operation

The volume obtained when calculating the room increases if there is equipment in it. This is due to the need for more extinguishing agent and the working area of the system. At the same time, when calculating this volume, elements of building structures made of non-combustible material are not taken into account.

When in suspended ceilings, it is necessary to consider reinforcement ceiling structure. Dynamic force can deform the ceiling and destroy the installation, further damaging equipment and people.

There are separate building codes for laying cables and installing electrical equipment. Pipelines are located at a certain distance from electrical wiring. With a possible explosion in the room electrical equipment protected according to the relevant regulations.

1.1. Features of the use of powder in automatic fire extinguishing installations.

Powder fire extinguishing installations are designed to extinguish fires of alcohols, petroleum products, alkali metals, organometallic compounds and some other combustible materials, as well as various industrial installations energized up to 1000 V.
The installations can be used to extinguish fires in industries where the use of water, air-mechanical foam, carbon dioxide, freons and other fire extinguishing agents is ineffective or unacceptable due to their interaction with combustible products circulating in production.
Fire-extinguishing powders are not recommended for use in extinguishing fires in rooms where there is equipment with large quantity open small contact devices, as well as in premises in industries where combustible materials are handled that can burn without oxygen.

Fire extinguishing powders are finely ground mineral salts with various additives that prevent caking and clumping. They have a number of advantages over other fire extinguishing agents:
- high fire extinguishing ability, as they are a strong flame retardant;
— versatility of application;
- a variety of fire extinguishing methods - volumetric, local or local-volumetric.

Distinguish powders of the general and special purpose. Powders general purpose designed to extinguish fires of combustible materials organic origin(flammable and combustible liquids, solvents, hydrocarbon liquefied gases etc.), solid materials, etc. These materials are extinguished by creating a powder cloud above the combustion source. Special purpose powders are used to extinguish certain combustible materials (such as metals) whose combustion is stopped by isolating the burning surface from the surrounding air.

The fire-extinguishing ability of general-purpose powders increases with an increase in their dispersion, while special-purpose powders almost do not depend on their degree of dispersion.
The effect of extinguishing fires with powder compositions is achieved due to:
- dilution of a combustible medium with gaseous decomposition products of a powder or directly a powder cloud;
- cooling of the combustion zone as a result of heat consumption for heating the powder particles, their partial evaporation and decomposition in the flame;
- inhibition chemical reactions, causing the development of the combustion process, gaseous products of evaporation and decomposition of powders or heterogeneous chain termination on the surface of powders or solid products of their decomposition.

It is generally accepted that the ability of powder formulations to inhibit flames plays a major role in extinguishing.
Successful extinguishing of a fire with a powder depends not only on the properties of the powder itself, but also on the conditions of its use. Under the conditions of use is understood the suitability of the powder for extinguishing a given combustible material and the mode of supply of the powder to the fire. The suitability of a powder is characterized by the compatibility of the powder with combustible materials. For example, sodium bicarbonate powder is suitable for extinguishing class B, C, E fires, but not suitable for extinguishing smoldering materials; MGS powder effectively extinguishes burning sodium, but it cannot extinguish potassium and a number of other metals, etc.

The feed mode is characterized the following parameters: the specific amount of fire extinguishing agent, the intensity of the supply of fire extinguishing agent and the extinguishing time. In addition, when choosing the powder supply mode and extinguishing method, it is necessary to take into account the nature of combustion and the properties of the combustible material. For example, when extinguishing class fires
B and C, which are characterized by inhibition of combustion, are most effective method feed - the creation of a finely dispersed cloud. In this case, a uniform distribution of the powder in the volume of the protected room is required. The powder must be supplied in atomized state, which is achieved special nozzles and displacing the powder from the vessel under high pressure (not higher than 1.6 MPa). When extinguishing class D fires, spilled flammable and combustible liquids, the powder must be supplied with a stream of low kinetic energy in order to evenly cover the burning surface without spraying and blowing the powder. In this case high pressure for the supply of fire extinguishing powder is not required and vessels designed for low pressure (up to 0.8 MPa) can be used.

The main requirements for fire extinguishing powders include not only the efficiency of extinguishing the flame, but also the ability to maintain their properties for a long time. Like many highly dispersed materials, fire extinguishing powders during long-term storage undergo various changes that worsen their quality: caking and clumping. Powder caking occurs as a result of exposure to moisture and ambient temperature. In the process of absorption of moisture from the air by the powder and subsequent dissolution of powder particles in condensed water, saturated solutions of the solid phase are formed. With a further increase in the amount of moisture, the solution becomes supersaturated, and crystals of the initial solid phase precipitate out of it in the zone of particle contact. Then, as a result of the formation of phase contacts, the crystals coalesce.

The crystalline powders of low hardness, which include fire-extinguishing ones, are also affected by the plastic deformation of the particles, as a result of which the formation of phase contacts from point contacts proceeds under the action of elevated temperatures and compressive forces (for example, its own mass). The caking effect is affected by the size of the particles, their uniformity and the nature of the surface. The tendency to caking increases with decreasing particle size. When compacting the powder, small particles, clamping the pores between large particles, increase the number of point contacts, which leads to more high ability to caking. Thus, the fire-extinguishing efficiency of powders depends not only on the inhibitory ability and dispersion, but also on the conditions of storage and transportation. To operational properties fire-extinguishing powders also include moisture (absorption of air moisture), fluidity (transportation through pipelines and hoses), compressibility (powder compaction under load), vibration resistance (retention of properties after exposure to regulated shrinkage), bulk density, compatibility with foams (degree of destruction of the foam in contact with powder), electrical conductivity, corrosivity, toxicity. There are several ways to combat caking, which are reduced either to reduce the moisture content in the powder, or to reduce the number and area of particle contacts. These include the removal of moisture by drying, the packaging of powders in waterproof containers, the use of water-repellent (hydrophobic) and water-absorbing agents, as well as additives that improve flow. It is possible to improve the performance and, as a result, the fire-extinguishing properties of powders not only by introducing special additives, but also by improving the technology of their manufacture.

1.2. Automatic powder fire extinguishing modules

Powder fire extinguishing module (MPP) is a device that combines the functions of storing and supplying fire extinguishing powder when an actuating impulse is applied to the trigger element. Modules according to the method of organizing the supply of a fire extinguishing agent can be with a collapsible (P) or non-collapsible (N) body.
According to the time of action (the duration of the supply of OTV), MPP can be of fast action (pulse - And) or short-term action (KD-1 and KD-2).
According to the method of storage of the displacing gas, MPPs are divided into injection (Z), with a gas generating (pyrotechnic) element (GE, PE), with a cylinder of compressed or liquefied gas(BSG).
MPP with a collapsing hull, shown in fig. 1, a, has a weakened lower part of the body. Under the influence of a command pulse, the gas generating device is turned on, the pressure inside the case increases and the weakened part collapses and releases the powder into the protected room. This design allows to significantly reduce the weight, however, after operation, the module cannot be restored.

Rice. one. Powder fire extinguishing modules:
a - with a collapsing body:
1 - collapsing hemisphere;
2 – module fastening;
b - with a non-destructive body:
1 - container for powder;
2 - spray nozzle;
3 - module mount

MPP with a non-destructive body, shown in fig. 1b has a special membrane and nozzles. When a command pulse is given, the gas generating device creates pressure in the housing and the membrane is destroyed. The powder comes out of the housing and is sprayed through the nozzle on a given area. After use, the module is recharged with powder and a new membrane is inserted into it.
On fig. 2 shows a module with a large amount of powder (up to 100 kg).

Rice. 2. MPP-100 powder fire extinguishing module:
1 - container with carbon dioxide;
2 - squib;
3 - starting head;
4 - safety valve;
5 - powder filling neck;
6 - pipe;
7 - a cylinder with a capacity of 100 dm 3 with fire extinguishing powder;
8 - conditioner;
9 - air valve;
URP-7 - manual start device, included in the MPP-100 kit

A module of the MPP-50 or MPP-100 type (see Fig. 2) is a steel welded cylinder 7 welded to the frame for powder poured through the neck 5 in the upper part of the cylinder. Pipe 6 is used to connect the powder pipeline with spray nozzles. A safety valve 4 is mounted in the neck cover. A cylinder 1 with carbon dioxide or nitrogen is attached to the cylinder 7 with powder, under a pressure of 0.8 MPa (8 kgf / cm 2), which is necessary to deliver the powder to the protected room. The gas from the cylinder 1 enters under pressure into the cylinder 7 with powder by means of a starting head 3 with a squib 2, which are switched on from the electric start system or from the manual start device of the URP. In the event of a fire due to an increase in temperature or when open flame the fire alarm system opens the shut-off device 3 of the cylinder 1. The gas from the cylinder enters the internal cavity of the housing 7 with the powder. In the housing, the powder passes into a fluidized state with the help of a fluffer 8, due to which it acquires the ability to flow through the distribution pipeline. When the pressure in the fire extinguisher body rises to 0.8 MPa (8 kgf / cm 2), the pneumatic valve 9 is activated, after which the powder from the body, through the siphon tube present in it, enters the distribution pipeline, then to the spray nozzles, and then to the protected area (in volume).
The module is equipped with a manual start device URP, which turns on the module through a starting head with a squib.

1.3. Powder fire extinguishing installations

Powder fire extinguishing installations consist of one or more modules and are divided into the following types:
- installations with a centralized source of working gas;
— installations with autonomous sources of working gas on each module.

Installations of the second type, in turn, are divided into:
- installations with simultaneous start-up of all modules included in its composition;
- installations with selective (single) start-up of modules depending on the place of fire.

Powder fire extinguishing installations are predominantly local fire extinguishing installations.
The installations must have a 100% reserve supply of fire extinguishing powder and working gas, located directly in the modules and ready for immediate use in cases where re-ignition of combustible material is possible (for example, with a continuous supply of flammable liquid with an autoignition temperature of 773 K and lower, in the presence of combustible substances and materials heated to a temperature that increases their self-ignition temperature, etc.). In all other cases, a 100% reserve supply of powder and working gas may be stored separately from the modules.

As modules for installations, automatic powder modules with a single source of working gas or modules with an electric start or with a cable start system.
Installation with a centralized source of working gas consists of the following assembly units:

1) modules containing a container with a fire extinguishing powder with a capacity of 100 liters, equipped with shut-off control and safety valves, as well as a distribution network with spray nozzles.
As modules for installations of this type, automatic powder fire extinguishers of a modular type are used. The number of modules depends on the required amount of fire extinguishing powder;

2) a centralized source of working gas containing containers (cylinders) for storing working gas, equipped with automatic shut-off and starting valves and a control device. Batteries and gas fire extinguishing installations can be used as a centralized source of working gas. If necessary, the capacity (power) of the working gas source can be increased by attaching stacked sections to the battery;

3) a collector containing a main pipeline with branches and designed to supply working gas from a centralized source to the modules;

4) switchgears designed to supply working gas to the required group of modules;

5) automatic fire alarm installations with heat, smoke and flame detectors, designed to detect a fire and issue signals to turn on stop valves centralized source of working gas and distribution devices, as well as sound and light alarms;

6) electric control unit of the installation.

Installation with an independent source of working gas includes the following assembly units:

1) modules containing a container with fire extinguishing powder of various capacities. A container equipped with an independent source of working gas with a shut-off and starting device, as well as control and safety equipment. Distribution network with spray nozzles.
As modules for installations of this type fire extinguishers of modular type with electric start are used. The number of modules in the installation is determined by the required mass of fire extinguishing powder;

2) an automatic fire alarm installation with heat, smoke and flame detectors, designed to detect a fire and issue a shutdown signal ventilation systems, to turn on the shut-off and starting devices of autonomous sources of working gas, as well as sound and light alarms;

3) power supply unit of the installation;

4) cable network to supply a start signal to each module.

The installation with an independent source of working gas includes a set of modules commercially produced. Installations have a fixed charge of fire extinguishing powder. The value of the protected area (volume) is determined technical specifications modules included in the installation.
It is recommended to use carbon dioxide, nitrogen or air as the working gas for installations. Air and nitrogen must be dehydrated.
The moisture content is allowed not more than 0.01% by weight.
All types of installations are allowed to operate in standby mode only if they are provided with a working gas charge in an amount not less than that allowed by the passport for the module for individual sources of working gas and for gas batteries for a centralized source.

The coefficient of filling module cases with fire-extinguishing powder (ratio of powder volume to case capacity) should not exceed 0.95.

1.4. Electric control of powder fire extinguishing installations

Equipment electrical control installation with a centralized source of working gas should provide:
- constant readiness of the installation for action in the event of a fire in the protected room;
- detection of a fire with an indication of the place where it occurred;
- issuing a fire signal to the control room of the facility and to the fire department, as well as a warning signal within the protected premises to ensure the evacuation of people;
- delay in the automatic start-up of the installation for the time necessary for the evacuation of people from the protected premises, in accordance with the requirements of the current building codes and regulations;
— automatic start installations for issuing the main stock of fire extinguishing powder from the fire alarm receiving station;
- repeated remote start-up of the installation for issuing a reserve supply of fire extinguishing powder;
- manual (in place) start-up of the installation with a completely disconnected electricity;
- the ability to disable automation and transfer the installation only to manual start;
- issuance of a signal about the inclusion of the required direction of the working gas supply, about the movement of gas, as well as about the start of the modules.

The supply of electricity to all receivers of the installation must be carried out according to the first category in accordance with the requirements of the PUE.

2. Calculation of powder fire extinguishing installations

2.1. Design features of powder fire extinguishing installations

Features of the design of powder fire extinguishing installations are as follows.
The type of installation is selected depending on the characteristics of the fire hazard of the protected technological process. The brand of powder and the method of extinguishing (surface, volumetric) are accepted, guided by reference data for powders.
The type of drive (cable or electric) is accepted depending on the fire hazard category of the protected premises. The electric start of the UPPT in fire-and-explosion hazardous rooms with production facilities of categories A and B is permissible only if explosion-proof fire detectors are used. Manual remote start devices (buttons, levers) should be located at the exit from the protected room and protected from accidental activation.

The modules may be placed directly in the protected area. Installations can be placed on technological platforms, whatnots, galleries or on special brackets. At the same time, the distance from fire extinguishers to technological equipment must be at least 5 m. If there is a shortage of production space, as an exception, the specified distance can be reduced to 3 m.

Pipelines of the distribution network are painted in gray, pneumatic communications - in blue, control and signaling units - in red.
If the total area of open (during fire extinguishing) openings is more than 15%, then only surface (local) extinguishing is accepted.
The thermomechanical system for starting fire extinguishers is placed both along the distribution network on rollers and directly under the protected equipment. The distance from the fusible lock to the nearest roller towards the fire extinguisher must be at least 0.6 m.

The manual start unit for fire extinguishers with a thermomechanical system is located at a height of 1.2–1.5 m from the floor in easily accessible places on escape routes, and in protected rooms - near the exit from them.
An inscription is posted near the manual start unit: “In case of fire, pull out the pin and lower the handle to the lower position”, etc.

2.2. Calculation of automatic modular type powder fire extinguishing installations

The calculation begins with the determination of the cross section area of the collector. With its length from a centralized source of working gas to the first module (up to 100 m), it is calculated depending on the number of modules connected to it:

(5.1)

where f - cross-sectional area of the collector, cm 2;
0,632 - empirical coefficient, cm 2, taking into account the gas flow rate per module, pipeline resistance, etc.;
n – number of modules, pcs.

If the length of the collector from the centralized source of working gas to the first module is more than 100 m, the flow area of the collector is calculated using general formulas.
It takes the following data:
- gas consumption per module 75 l s -1 ;
— initial gas pressure in the centralized source 12.5 MPa, residual gas pressure in the source 1.5 MPa.

In volumetric powder fire extinguishing, the number of modules is determined based on the required amount of powder and a single charge of the module:
(5.2)

where M p, M opa - respectively, the required mass of the fire extinguishing powder and the mass of the module charge, kg;
V to – capacity of the module body, m 3 ;
? – powder bulk density, kg/m3;
K zap - safety factor, taken equal to 0.35–0.95.

The mass of fire extinguishing powder Mn is determined by the formula

where K = 2 - with the possibility of re-ignition, in other cases K = 1;
V def - the volume of the protected premises, m 3;
qnv - volumetric fire extinguishing ability of the powder, kg / m 3;
f pr - the area of openings opened during a fire, m 2;
q nadd - the norm of the additional mass of the powder, is taken equal to 2.5 kg / m 2 at fpr \u003d 1–5% and 5 kg / m 2 at fpr = 5–15% of the area of enclosing structures. With a larger ratio of areas, it is recommended to use local fire extinguishing. In this case, an additional amount of powder, as a rule, should be used to organize a curtain of powder jets at open openings.

When determining the volume of the protected premises, it is allowed to subtract from its geometric volume the volume occupied in it by non-combustible building structures that do not have an internal volume that communicates with the volume of the protected premises.

In case of local fire extinguishing by volume (outside the technical unit or equipment), the estimated volume V l is determined by the formula

where a, c, h - respectively, the length, width and height of the protected unit or equipment, m.

Nozzles for the release of powder during volumetric fire extinguishing should be placed in such a way that the powder is evenly distributed throughout the entire volume of the protected room; in case of local fire extinguishing by volume, powder jets should be directed to the surface of the equipment located in the protected volume.

The total number of moduli N mods for powder quenching by area (surface) is defined as the largest of two values:

where N mod1 is the number of modules determined necessary quantity powder;
N mod2 - the number of modules, determined by the ratio of the entire protected area and the area protected by one module.

Number of modules N mod1 is determined by formula (5.2). Powder weight M p is determined by the formula

(5.6)

where K – has the same meaning as in formula (5.3);
F def - protected area of the premises or equipment, m 2;
qn.f - surface fire extinguishing ability of the powder, kg / m 2.

The number of modules N mod2 is determined by the formula

(5.7)

where K and b> F def are the same quantities as in formula (5.6);
F1 - the area protected by one nozzle, m 2;
n - the number of nozzles in the module.

In order for the entire protected area or surface of process equipment to be sprayed with fire extinguishing powder, the distance from the nozzles to the enclosing structures should not exceed 1.5 m. The distance from the protected surface (area) to the nozzle should be at least 2 m and not more than 4.5 m .

The greatest extinguishing effect is achieved at a distance of 3.0–3.5 m. If there are technical platforms and ventilation ducts with a width or diameter of more than 0.75 m, additional modules must be installed under it, taken into account when calculating according to formula (5.7).

Note that if the number of modules determined by formula (5.5) differs slightly from an integer, then it can be reduced to an integer by varying the fill factor of the Kzap module or by simply rounding the number of modules up.
The number of modules determined by formula (5.7) is always rounded up.

2.3. Calculation of impulse powder fire extinguishing installations

The calculation of powder fire extinguishing installations of pulsed local type is carried out in accordance with the methodology. Number of pulsed powder modules (MIP) N l , pcs., is determined by the formula

(5.8)

where S y - the area of the protected area (zone), for equipment, the area of the equipment dimension, increases by 10%, m 2;
S n - normative area, m 2;
K1 - coefficient of uneven spraying of the powder, used in the group installation of the MIP, is taken equal to 1.2;
K2 - safety factor that takes into account the shading of a possible source of fire and depends on the ratio of the area shaded by the equipment S z to the protected area S y, is determined by the formula

(5.9)

where S - the shading area, defined as the area of the part of the protected area, where the formation of a fire seat is possible, to which the movement of powder from the MIP in a straight line is blocked by structural elements impermeable to the powder.

K3 - coefficient taking into account the change in the fire extinguishing efficiency of the powder used in relation to the combustible substance in the protected area compared to A-76 gasoline (Table 5.1);
K4 - coefficient taking into account the degree of leakage of the room. K 4 \u003d 1 + V F neg, where F neg \u003d F / F pom - the ratio of the total area of leakage (openings, slots) F to common surface room F pom, coefficient B is determined from fig. 5.3.

Regulatory area S n is determined by the formula

(5.10)

where V n - the volume protected by one MIP of the selected type, m 3;
K5 – coefficient characterizing the characteristics of the spraying of the MIP powder of the selected type (determined by the technical documentation for the MIP).
If the height of the equipment in the protected area exceeds 1.4 H (where H is the discharge height) for the selected type of MIP, the latter are installed in tiers with a step at a height of 0.8 ... 1.4 H, provided that their placement should ensure uniform filling with powder protected volume. MIP can be installed on suspended structures. At the same time, constructive measures must be taken to prevent the consequences of the impact on the suspension elements of the dynamic force that occurs when the MIP is triggered, equal to five times the weight of the installed modules.
V n and H are accepted for the MIP of the selected type in accordance with the specifications of the developer-manufacturer.

Calculation of powder fire extinguishing installations of impulse volumetric type.

Number of MIPs N , pcs., necessary to protect the premises, is determined by the formula

(5.11)

where V p is the volume of the protected premises, m 3;
V n - the volume protected by one MIP of the selected type, m 3;
N p - the number of MIP required to neutralize the leakage of fire extinguishing powder through permanently open openings, pcs.
The values of the coefficients K 1 and? K 3 are determined in a similar way to the calculation of the local-type RFID.

Table 5.1

Coefficient K 3 of the comparative effectiveness of fire extinguishing powders when extinguishing various substances

When protecting open technological installations as Sn is taken the area of the maximum rank of a class B source, the extinguishing of which is provided by the data of the MPP (determined by technical documentation at MPP, m 2).

If fractional numbers are obtained when calculating the number of modules, the next larger integer in order is taken as the final number of modules.
For offline installations fire extinguishing, simultaneous group launch of the entire number of modules N, obtained by calculation, should be ensured.

3. Features of placement, installation and operation of powder fire extinguishing installations

3.1. Requirements for the placement of equipment for powder fire extinguishing installations

The centralized source of working gas, the fire alarm installation and the electrical control unit of the installation should, as a rule, be located in special rooms that meet the following requirements:
— fire resistance limit of walls and ceilings not less than 0.75 h;
- height not less than 2.5 m;
— a floor with a hard surface that can withstand the load from the installed equipment;
— air temperature within 288–309 K;
— illumination not less than 150 lx;
- the environment is non-explosive.

A lamp and a scoreboard should be installed in front of the entrance door from the outside. In cases justified by the project, the specified assembly units of installations, except for the fire alarm receiving station, can be placed in industrial fire-safe rooms. In this case, they must be fenced with a glass partition or metal mesh and equipped with warning signs.

Modules should be installed, as a rule, in a room adjacent to the protected one. The room in which the modules are located must be separated from the protected room by a partition with a fire resistance of at least 0.75 hours. Openings in the partition must be protected by fire-resistant doors with a fire resistance of at least 0.75 hours. allowed to attach to building structures building.

The manifold for supplying working gas and cable wiring are recommended to be laid along overpasses together with other technological wiring. The collector and cable network must be protected from mechanical damage.

Nozzles for the release of powder during volumetric fire extinguishing should be placed in such a way that the powder is evenly distributed throughout the entire volume of the protected room. Spray nozzles must be placed in such a way that the powder jets are directed to the surface of the equipment located in the protected volume.

In case of local fire extinguishing, nozzles should be placed so that in case of fire the entire surface of the protected technological equipment or protected area is evenly dusted with fire extinguishing powder.

Devices for remote start-up of installations (buttons, levers) should be placed at the entrance to the protected room with protection from accidental use.

3.2. Requirements for protected premises

Protected premises should have, as far as possible, minimum area openings open during firefighting. Windows and doors must have automatic closers.
Ventilation openings in case of fire should be automatically closed, and the ventilation system should be turned off when the fire extinguishing installation is triggered. In relation to installations of type 2b, this requirement is not feasible. In this case, it is necessary to compensate for possible powder leaks with its additional amount: with a total area of openings of 1–5% of the total area of walls, ceiling and floor of the room - by 2.5 kg per 1 m 2 of an open opening; with a total area of openings of 5–15% - by 5 kg per 1 m 2.

The ways of evacuation of people from the premises must ensure the exit of service personnel for no more than 30 s. If this requirement is not met, then automatic control the installation must introduce a device that ensures the delay in the issuance of fire extinguishing powder until the end of the evacuation of people from the protected premises.

3.3. Requirements for installation, testing and commissioning

Installation of the units must be carried out in accordance with the working drawings of the project and the installation instructions attached to the supplied assembly units. Deviation from the project or installation instructions is allowed only upon agreement with the design organization and with the manufacturing plants of assembly units.

All assembly units must be subjected to input control in accordance with the requirements specifications and passport assembly unit.
Installation of the units must be carried out by trained personnel using special tool and equipment to ensure the proper quality of work.
Need to keep a journal installation work, which indicates the brand of the installed equipment, defects in this equipment identified during installation, last name, first name, patronymic and position of persons responsible for installation from among the leading technical personnel.
The journal notes all deviations from the project or installation instructions, as well as documents authorizing these deviations.

The installation of all pipelines must ensure: the strength and tightness of the pipe connections and the points of attachment of devices and fittings to them, the reliability of fastening the pipes to the supporting structures and the structures themselves on the bases, the possibility of their visual inspection, as well as their periodic purging.

When installing the collector pipelines, it is necessary to use detachable connections. Welded joints are allowed, providing conditions for the movement of compressed gas.
The quality of installation work should be checked at the end of each operation by external inspection and pneumatic tests in accordance with the instructions of the passport of the assembly unit.
The working gas supply manifold must be subjected to pneumatic testing pressure 10.0 MPa for 120 s. Leakage of gas at the junction of the pipeline is not allowed. Leak control is carried out by washing the joints.
After completion of installation work and testing for strength and density, pipelines must be painted first with protective paint, and then with identification paint. Identification paint must comply with the requirements of GOST 12.4.026–76.

Upon completion of all installation work and checking their quality, the installation is presented for acceptance to the customer. Acceptance must be carried out with the participation of a representative of the fire department.
At the request of the customer, the installation can be subjected to additional tests(including fire), carried out according to a special program.

Installation into operation is accepted on the basis of a bilateral act. Other requirements for installation, commissioning and commissioning of installations should be taken according to the relevant normative documentation for installations of water, foam and gas fire extinguishing, approved in the prescribed manner.

3.4. Features of the operation of powder fire extinguishing installations

During the operation of powder fire extinguishing installations, the following types maintenance (TO):
- daily;
- monthly;
- semi-annual;
- after the expiration date of the powder
- and once every five years.

Technical means of UPT must comply design solutions, technical documentation of manufacturers and have certificates of conformity.
After each operation of the UPT, the pipelines through which the fire extinguishing powder was supplied must be purged with compressed nitrogen.

During the daily technical inspection it is necessary:
- to carry out an external inspection to identify any damage to the installation elements;
- make sure that there are seals on the safety valve and the safety check of the start handle;
- check the presence of a cable on the rollers, the state of grounding;
- make sure that the alarm (if any) is working and that the pressure complies with the required parameters according to the readings of the pressure gauges;
- check the presence of voltage at the control panel and the condition of fire detectors in installations with electric start.

During monthly maintenance check:
- the condition of the fasteners, threaded connections;
- pressure in cylinders according to pressure gauges;
- performance of fire detectors.

Places with a damaged coating must be cleaned of rust, followed by the application of an anti-corrosion coating.
During semi-annual maintenance, it is necessary to perform work in the scope of monthly maintenance, as well as:
- check the value of the residual deformation of the cable and, if necessary, tighten it;
- check or technical certification pressure gauges, cylinders, vessels at the expiration of the examination period;
- check the condition and performance of the pneumatic (threshold) valve on the vessel;
- to weigh the launch cylinders.

During maintenance after the expiration date of the fire extinguishing composition, in addition to the works listed above, it is necessary to charge the powder in specialized organizations and check distribution network connections.

During maintenance once every 5 years, it is necessary to carry out work on maintenance and additionally conduct an inspection of vessels with powder and gas cylinders with working gas in accordance with the requirements of Gosgortekhnadzor, as well as check the operation of the safety valve.

Academy of the State Fire Service of the Ministry of Emergency Situations of Russia,
Textbook for educational institutions EMERCOM of Russia, 2007.

The importance of extinguishing fires with the help of special powder formulations has not lost its relevance for several hundred years. It is easy to explain - only powder fire extinguishing is used in case of ignition of some specific substances and materials - light and alkali metals, sodium and lithium, metal-containing compounds.

Powder fire extinguishing principle of operation

Modern powders for extinguishing fires differ in composition, degree of grinding and, accordingly, are used to eliminate fires of various classes.

By appointment, powders for fire extinguishing are:

General purpose - elimination of fires A, B, C classes.
Special purpose - the elimination of combustion of alkali metals, etc. substances.

What is the principle of action of powders? The effectiveness of powder fire extinguishing is achieved due to the fact that OTV (fire extinguishing agent) affects the fire in several directions at once:

Firstly, part of the heat from the fire seat is spent on heating all the powder particles that have fallen into it.
Secondly, the mixture blocks the further spread of the flame, creating a thick, impenetrable cloud.
Thirdly, the combustion reaction itself is inhibited due to the well-chosen composition of the mixture of powders.

Varying with the percentage of powder components and changing the main constituent element, mixtures intended for extinguishing are selected. different types fires.

Powder fire extinguishing scheme

Installation at the facility of an automatic installation of powder fire extinguishing (briefly AUPP) will allow:

timely detect a fire;
automatically apply powder at such an intensity as to extinguish the fire and not cause re-ignitions.

AUPP can be of modular or aggregate design.

In the first case, an n-th number of modules (tanks with powder) equipped with a launcher (launcher) is installed at the facility. The models are integrated with each other, and are also connected to the fire detection system and the activation of their launch.

In the case of aggregate AUPP, these settings are represented centralized systems with a single reservoir for the storage of OTV and pipelines extending from it, through which the powder enters the fire zone.

A scheme is laid in the powder fire extinguishing installation project, on which the designer notes:

type of AUPP used;
system components;
connection of the installation with others engineering systems building;
fire detectors and sirens;
manual start devices;
doors with sensors, etc.

When preparing a powder fire extinguishing scheme, developers must use the rules for placing fire fighting equipment (see GOST No. 12.3.046, 12.4.009, NBP No. 88-01, etc.).

Advantages of powder fire extinguishing

You can choose a powder composition for objects of any fire hazard class. With the help of PP, fires of classes from A to E are extinguished. In addition, this fire extinguishing option has a number of other advantages:

availability of installations;
simple design and installation;
the possibility of long-term storage of powders - from 5 (at least, according to NPB No. 170-98) to 10 years, subject to the rules for the operation of containers;
use for extinguishing specific fires where other substances (water, gas, foam) are not used;
versatility - use to extinguish a number of fires;
wide temperature Range application of powders - from -50 degrees. up to +50 deg. at humidity up to 98%;
no need to seal the room during extinguishing, as, for example, is required for aerosol or gas fire extinguishing;
fast response - no more than 5 seconds from the time of fire detection;
safety for the environment - the absence of toxic or ozone-depleting elements in the composition.

Powder fire extinguishing is actively used in administrative buildings, industrial buildings, warehouse complexes, garages, parking lots, electrical installations, and is indispensable for facilities where there is a risk of ignition of alkali metals.

Modular powder fire extinguishing systems

Modular systems, as mentioned earlier, are powder fire extinguishing complexes consisting of interconnected modules.

The design of a separate module is as follows:

The case is metal, filled with OTV inside.
An element that generates gas (or a capsule already filled with gas).
Temperature sensitive sensor.

The gas is needed in order to build up overpressure before starting the powder. If a gas generating element is built into the module, there may be a slight delay in the release of OTV, but the duration of the powder release itself increases.

Depending on the purpose of the object capital construction, pick up modular systems appropriate size and performance.

Modules with an explosion-proof housing (marked “vzr”) can be safely installed at fire and explosion hazardous facilities - oil refineries, chemical plants, oil product warehouses, etc.

Rooms up to 100 cubic meters, without the constant presence of people, with periodic visits, are equipped with simple automatic settings powder fire extinguishing. In the same place where a mass stay of people is planned - theaters, cinemas, shopping malls and others public places – modular plants are carried out in accordance with GOST No. 12.3.046 and NBP No. 88-01.

In any case, it is advisable to entrust the design and installation of AUPP to a professional.

Systems Theme powder extinguishing fires is extensive and requires a detailed study a large number information. This article has collected a brief squeeze on the powder type of fire extinguishing, allowing you to find out the technology right choice optimal module. The classification of installations will give a clear understanding of how to choose best model and what algorithm of installation work to implement. The material contains recommendations and useful tips that will help you avoid a large number of mistakes.

History of creation

The story begins in 1770. Colonel Roth from Esslingen is mentioned for the first time. The participants in the experiment were a barrel of aluminum alum for spraying and gunpowder. The experiment was so successful that the fire department was keenly interested in it.

In Russia, the experiment was continued by the chemist Sheftal. But that was already in the 19th century. The complex submitted for consideration was named "Pozhargaz".

The composition included:

Bicarbonate soda.
Alum.
ammonium sulphate.
Earth is infusor.
Asbestos shavings.

The experiment was carried out so successfully that "Pozhargaz" was put on production release.

Order, in those days, left a deep impression. Readiness - 15 seconds. The cord was lit, and with an interval of 4 seconds, a pop was heard, like a countdown to the explosion. In the thirties, technology shifted towards testing small bombs with ordinary papier-mâché. The "Description in Popular Scence" of this method, as being very ecological, aroused great interest. In an explosion with a temperature of 200 degrees, papier-mâché was sprayed.

Already in the forties of the 20th century, the procession of fashion began around the world: Europe, Asia, Russia, America. Further improvement made it possible to use a temperature fork from -50 to +50. certain kind additives did not allow the mixtures to absorb moisture.

Easy handling, low cost, unobtrusive service. Big choice. All this attracts, especially where you can work under stress.

But there is also a downside to this system. The most important of these is the danger to health. But, if you establish the correct evacuation, then there are no obstacles.

In the Soviet Union, in connection with the emerging threat at nuclear power plants, in the 1960s, the issue escalated. Development has begun. Twenty years later, the powder fire extinguishing system was tested, showing that the method is effective on surfaces that do not have voids and cracks. That this method works best in the beginning.

In situations where alkali metals are burning, there is no alternative.

The questions that remain unclear are:

Cooling with the expenditure of heat to heat the microparticles of the powder.
Liquefaction of waste clouds.
The effect of localization in bottlenecks.
Inhibition of the combustion process.

Clear parameters are allocated only for alkali metals.

Systems

Fires are detected almost immediately and the command is sent to the control panel. This is the module system. It is inexpensive and not difficult to manage. However, its filling is harmful to buildings.

It is very dangerous for human health. Causes poisoning on direct contact. That is why it is applicable in rooms without maintenance:

Substations.
Sheds.
Closets.

The model is released in three types A: Automatic, manual and offline.

Type - Tungus. Fixing is view-independent and is divided into centralized and modular types. In centralized solutions, the mixture comes from a common tank, and in another solution, in modules installed on equal distances from each other. They are activated by a signal from the remote control.

Quenching can be volumetric and surface. With surface quenching, the mixture is evenly distributed over the area. When volumetric, it is filled to the entire cubic capacity.

The type of unit is chosen according to the indicators of harmfulness and the nature of the stored substances. The time the device enters the mode matters.

If we talk about ecology, then suspensions can be just fertilizers, but when in contact with the human body, the consequences are bad.

Choosing the optimal module

One of the most popular samples on the Russian market is, read more about which in the article at the link. Upon closer examination of the Buran -2.5 - 2s installation, it can be triggered both from a signal from the remote control and from its own sensors. There is an independent device or part of a complex of automatic equipment. The design allows being in any interiors - offices, business centers.

Equal in popularity to the model Buran 8vzr. It is explosion-proof, can be mounted on oil depots, automobile gas stations. Short response time, explosion resistance, work over large areas.

Other popular Tungus and Brand modules are used, as a rule, in the following places:

Residential houses.
Industrial zones.

The technical characteristics of the Tungus-2 system are selected according to the type of materials protected from fires.

Functions performed:

Self-notification.
Fire isolation.
Saving structures.

The issue of human safety comes first, so choosing the right module is extremely important.

Outperforms similar brands in terms of:

Ecology.
Automation.
Versatile applications.
Great return.
Easy installation.
Relatively low price.
Instant action.
Blockade of fire in the bud.
Universal composition of powders.

Mounting

Installation sites are selected taking into account the characteristics of the object according to special rules and instructions. Visual inspection of the unit for the integrity of the body and seals to ensure correct delivery.

To evenly distribute the contents inside the device, turn sharply around the axis several times. Screwed on wall or ceiling mounting plate for the unit. If the area is large - evenly over the entire area. Entrust the execution of work only to professionals, which will guarantee the preservation of property.

Classification

AST with powder fire extinguishing is mainly used in non-residential buildings where the use of water is undesirable:

Document storage.
Museum valuables.
Manufacture of chemical products, alkali metals.

Supply from one container – centralization. Contents in one place of application – module.

Automatic firefighting is usually a mobile design due to the properties of the dispersion, the release of which requires high pressure.

Automatic installations are classified on the basis of:

Design.
Ways to extinguish fire.

The premises where powder flame containment units are installed must be equipped with light displays - “EXIT”, “POWDER! GO AWAY”, which light up before the start of extinguishing.

False positives

One of the reasons is dampness. Water, getting on the sensors, corrodes the contacts, short circuit - start. If there are a lot of fire extinguishers, up to a hundred pieces, an error in assembling the circuit is possible. The way out is to divide the area into zones. The start relay is separate. There are trips during power surges.