Fire extinguishing system. Various fire extinguishing installations

Many facility managers do not approach the issue of choosing fire fighting equipment seriously, believing that nothing like this will happen to them.

As a result, when a fire appears, completely inappropriate substances are often used to extinguish it.

To prevent this from happening, you must entrust the choice of installing fire extinguishing systems to professionals. Only they are able to correctly assess the specifics of the object and determine which type of equipment will be most suitable.

What is the installation data?

This is a set of devices that are triggered if the critical values of temperature and smoke at the protected object are exceeded. Standalone installations Fire extinguishing systems are usually used to localize and eliminate the source of fire at the very beginning of its appearance.

The use of such equipment is regulated by existing regulatory documents and is recommended for both residential and public and industrial buildings.

Variety of AUP

The equipment used to extinguish fires varies depending on constructively. Depending on this parameter, it can be of the following types:

Aggregate;
Modular.

Besides, fire protection installations are equipped with automation equipment. Based on the presence of these elements, the equipment requires manual control or using automatic systems.

Automatic fire extinguishing installations can work with various types of agents. Moreover, there are models on the market that use one or more of the means.

Such a large number of means used to extinguish a fire has led to the emergence of in various ways fire fighting. Based on this, the following types are produced:

Robotic fire extinguishing installations;
Volumetric;
Superficial;
Local.

What do they represent? different kinds equipment, where their use is allowed, what advantages they have, the purpose of an automatic fire extinguishing installation? Let's start our consideration with one of the simplest and most accessible substances - water. It is available and has a low cost.

Water models

Systems that work with this fire extinguishing agent, have differences in the design of sprinklers. They can be:

sprinkler;
Deluge.

The first ones are intended for objects where there are materials with increased flammability. In them, the elimination of fire sources must be carried out simultaneously throughout the entire area of the room.

Deluge fire extinguishing installations can serve as water curtains in cultural and public institutions, and are also suitable for extinguishing technological equipment, containers with petroleum products. They are ideal for creating a water curtain.

Gas installations

This is a set of devices for eliminating fires, in which two groups of gases can be used as agents:

Thinners such as nitrogen, argon;
Inhibitors or freons.

Those using the first group of fire extinguishing agents are characterized by large dimensions and weight. While those working with inhibitors are more compact, at the same time the concentration of gases in them is significantly lower and is only 13% of 60% for the first group.

Not long ago, systems appeared that use perfluoroketones. They are distinguished by high environmental safety and can be used on any objects, as they do not have a detrimental effect on objects and materials.

Watch a video about these systems:

Stationary gas installations fire extinguishing systems have differences in design and are divided into:

Modular;
Centralized.

Powder systems

Such installations have the widest scope of application. They are designed to eliminate fires of any class, as well as electrical appliances that are turned on.

Let's watch a video about this system:

Autonomous fire extinguishing installations for electrical control rooms are used both to localize and eliminate fires in part or all areas of the room. But at the same time, such installations cannot be used at facilities where:

Combustible materials;
Chemical mixtures that can smolder and burn without access to air.

Devices of this type are most often used at facilities where flammable liquids and highly flammable compounds and petroleum products are located. They are divided into deluge and sprinkler fire extinguishing systems and in design terms are very similar to water installations. The only difference between them is the presence of a reservoir. In this case, all components of the fire extinguishing agent are stored separately.

For the dosage of chemical agents in such installations the following can be used:

Pumps;
Dispensers;
Foam mixers;
Bucky.

In addition, sprinklers or generators are used in foam systems.

Aerosol systems

They use a special composition as a fire extinguishing agent that can act on the source of the fire. They are among the oldest and were first used in 1819. Firstly autonomous systems Fire extinguishing agents used black powder, clay and water as extinguishing agents. But over time, their use was suspended due to low efficiency.

Let's watch a video about this fire extinguishing system:

Modern stationary aerosol fire extinguishing installations cannot ensure complete elimination of the source of fire and therefore cannot be used for:

Fibrous and other materials prone to spontaneous combustion or smoldering;
Chemical compositions and polymers that can burn without air access;
Metals, pyrophoric compounds.

Aerosols are also harmful to human health, so installations where they are used cannot be used in rooms that cannot be left by people before the system starts operating.

How to choose the right fire extinguishing system

The most important criterion, which is oriented towards in this case are the features of the object. Based on them, a specific robotic fire extinguishing installation is selected. If you intend to use the equipment in public, warehouse, archival and cultural buildings, then you can immediately discard the use of foam as a fire extinguishing agent. In addition, recently it has practically not been used on any of the possible objects.

Based on the characteristics of the protected premises, the main selection criteria can be formulated:

Efficiency;
Safety for people;
Impossibility of causing damage to material assets.

Systems with solid fire extinguishing agents are most suitable for these criteria. It is possible to use water pumping fire extinguishing systems, since horses are safe for people. But at the same time, property suffers greatly from them. And if such a system works on top floor, then tons of water will fall on the lower ones, which will cause damage to both material assets and the building itself.

Therefore, fire extinguishing pump systems are most often used with fine spray systems that have minimal impact on the environment.

It is also possible to use gas SAPT. However, their use, especially with freons, is deadly to humans. Therefore, at facilities where people are present, they usually give preference to the perfluoroketone group of gases. They are practically safe. But it should be borne in mind that the premises where it is intended to be used gas systems There are strict requirements for tightness, and in addition, such equipment is quite expensive.

Maintenance and operation

It's not enough to do right choice, it is also necessary to install the equipment in accordance with existing requirements. After the pipelines have been laid and devices have been installed and connected to the electrical network, tests must be carried out. By the time they are completed, it is necessary to evaluate the strength and density of all pipes and check the quality of electrical wiring insulation.

Trial pumping unit Fire extinguishing consists of several stages. At the first stage, an inspection of equipment, both technological and electrical, is carried out. Then, autonomous tests are carried out on individual system components responsible for controlling its operation.

An external inspection also involves checking whether the placement of devices corresponds to the project drawings. Autonomous tests are necessary to assess the correct interaction of all components and elements of the system. Completion of all work and commissioning of the installation is confirmed by an acceptance certificate. They must be accompanied by design drawings and other documentation.

Used in food factories automatic installations: water extinguishing - sprinkler and deluge; steam, gas and powder fire extinguishing. The choice of one or another installation is carried out based on the properties of substances and materials formed in production, technological requirements and feasibility studies.

Automatic systems make it possible to prevent or extinguish a fire in a timely manner. Without human intervention, they detect a fire and, after giving an alarm, begin to extinguish the fire in the initial stage of its development.

Schematic diagram installations automatic fire extinguishing shown in Fig. 61. When a fire occurs, the detector sensor 4 detects the location of the fire and notifies the system switching device 5, which, in turn, activates the fire extinguishing agent supply device 2 through the release device 5, which eliminates the fire.

Rice. 61. Schematic diagram of an automatic fire extinguishing installation:
1 - apparatus for storing fire extinguishing agent; 2 - device for supplying fire extinguishing agent; 3 — system switching device; 4 - device for fire detection and notification; 5 - fire extinguishing agent release device; 6—combustion center

Based on their operating principle, automatic extinguishing systems are divided into devices designed to supply a fire extinguishing agent evenly over the entire area of the room. For this purpose, sprayed water, foam or powder compositions are most often used. There are devices for filling the entire volume of the protected space with fire extinguishing agent. In such cases, water vapor, carbon dioxide, and inert gases are usually used. Local systems designed to protect technological devices and equipment are also used. For this purpose, substances that inhibit the combustion process and powder compositions are used.

Sprinkler installations are designed for extinguishing local fires in individual areas of non-explosive premises, and deluge installations are intended for general fire extinguishing throughout the entire area of premises, including explosion-hazardous ones. The pipeline network of sprinkler installations is equipped with sprinkler heads (Fig. 62). Their outlet is normally closed by valve 5, which is held by copper plates soldered with low-melting solder - lock 6. The locks are designed for a certain temperature (72, 93, 141, 182 ° C). If a fire occurs under the head, rising up warm air melts the solder, the plates self-open, the valves are pushed out of the seat using a membrane, and the hole opens. Water from the hole hits the socket and is sprayed in all directions within a radius of 1.5. ..2 m on the floor area under the sprinkler head. Several heads can be triggered at the same time, which ensures intensive fire extinguishing. A distinctive feature of sprinkler systems is that their piping system is constantly filled with water or air under pressure. When the valve of one or more sprinkler heads is opened, the pressure in the system drops, which is a signal to a special device to turn on the pumps.

Rice. 62. Automatic fire extinguishing installation:
a - diagram of the sprinkler head in working and non-working condition (1 - socket; 2 - arc; 3 - valve; 4 - nozzles; 5 - supply pipeline; 6 - fusible lock); b - diagram of a sprinkler installation (1 - centrifugal pump; 2 - water tank; 3 - main pipeline; 4 - supply pipelines; 5 - sprinkler head; 6 - control and alarm valve; 7 - signaling device)

Fig.63. Steam extinguishing scheme;
1 - boiler room: 2 - process pipelines, 3, 4 - valves; 6— nozzle for steam supply; 7 - taps; 8 - rubber hose

The deluge plant's piping system is not normally filled with water, and the deluge heads have holes that are constantly open. When a fire occurs, the detectors give a signal to turn on the pumps and water enters the room through all deluge heads.

Deluge installations are used in the same way as protective water curtains with remote or manual control, to protect openings (doors, windows, arranged for technological purposes), as well as to separate rooms in order to localize the source of fire and prevent its spread to adjacent rooms.

At distilleries, premises for storing alcohol in tanks, at bakeries, ovens are equipped with automatic steam extinguishing installations. In the steam extinguishing system (Fig. 63), both superheated and wet steam are used as a fire extinguishing agent. The vapor concentration in the air is 35% vol. and is considered fire extinguishing. The estimated time to create such a concentration is 3 minutes. The steam supply intensity for rooms where ventilation is provided is 0.005 kg/(s*m3). and for rooms or various technological devices in which there is no air exchange - 0.002-0.003 kg/(s*m3).

The steam extinguishing system can only operate when the steam boiler room is operating. In addition, the steam extinguishing system can pose a danger to people, since the steam has a temperature of 160-180 ° C, so it can only be turned on after making sure that people have left the room.

Variety automatic systems powder fire extinguishing system is the local fire extinguishing system ASPGP (Fig. 64). When a signal is sent from the automatic sensor-detector 1 about the occurrence of a fire, the power and control unit 2 is switched on by the limit switch 3, the flame suppression device 4 - the PP-9 squib and the gas-generating charge. The inert gases generated by the charge emit powder through the nozzle into the fire 5 in the form of a sprayed torch.

Rice. 64. Automatic local fire extinguishing system:
1 - sensor. 2 — power supply and controls; 3 - limit switch; 4 — flame feeder; 5 - fire source

Automatic liquid carbon dioxide fire extinguishing systems are used to extinguish liquid and solid materials. Carbon dioxide can be stored at enterprises in isothermal tanks under pressure up to 2.5 MPa or in steel cylinders under pressure up to 7 MPa. Carbon dioxide is released through a pipeline through a special nozzle into the protected volume of the building. When the dioxide flows out of the nozzle, it turns into an aerosol (snow-like mass) and then into a gas. The gas, spreading throughout the volume of the protected object, displaces the air, and combustion stops.

The fire extinguishing concentration of carbon dioxide is 23%. but to stop burning it is brought up to 30%.

From ancient times to the present, fires have been a serious problem in people's lives. Some particularly severe fires go down in history and change the life of entire cities and even states. This was the case, for example, with the Great Fire of London in 1666 or with the famous fire of Moscow during Patriotic War 1812. Therefore, it is logical that every property owner strives to protect himself from fire.

Modern fire protection systems provide a high level of safety, but the issue of economic efficiency in this case is no less important. It is unlikely that anyone will want to pay huge amounts of money for an automatic fire extinguishing installation if the likelihood of a fire at that particular site is extremely low.

The main criterion when choosing a fire extinguishing system and the amount of money that the owner of the property is willing to spend on it is the potential damage that could be caused in the event of a fire. To navigate through the different options fire protection systems, the formula S = A + B is used, where A is the estimated loss (thousand rubles per year) from a fire at a protected facility after the system is activated, and B is the cost of development, installation and annual maintenance of an automatic fire extinguishing installation.

It should also be noted that the estimated losses include not only the actual destruction of property, but also the income that will be lost due to the failure of burnt equipment. When analyzing various options fire extinguishing systems, the most preferable one will be the one that involves smallest value S.

You can often find an option in which only fire alarm. She happens to be effective means fire detection, but this is where its functions end, since it cannot actually extinguish the fire. At the same time, the state system fire department is not as prompt as many property owners would like - the average time of arrival of the fire brigade is about 10 minutes. This is a significant period of time during which many valuables can be destroyed by fire irrevocably.

In addition, in last years There is a tendency for this time to increase. In large and medium-sized cities, population growth leads to an increase in the number of cars, and throughput the roads are not changing. The result is traffic jams that are difficult for a fire truck to overcome even with a flashing light and siren. In rural areas the situation is no better, but the problem there is not at all due to traffic jams. Lack of road repairs, understaffed crews, outdated equipment - all this is the reason for the increase in the average time of arrival to a fire.

To completely protect yourself from fire or at least minimize its consequences, various objects automatic fire extinguishing installations (AFS) are used. They are able to independently detect and extinguish a fire without human intervention. It often happens that the operator learns about the fire after it has been extinguished.

Automatic fire extinguishing systems differ from each other in several ways. Although they are designed to serve the same purpose, their design is sometimes fundamentally different from each other. Below is a table showing the most common methods for classifying automatic fire extinguishing installations:

AUP classification
By type of fire extinguishing agent	By design	According to the method of extinguishing	According to the method of commissioning
	sprinkler	By volume	Manual launch
	Deluge	By area	Automatic start
Powder	Aggregate	Locally to the source of fire	Remote start
	Modular		Combined method
Aerosol

The most popular, reliable and simple automatic fire extinguishing system is a sprinkler. Due to their efficiency, these installations are used at almost any facility, including those of special importance. According to statistics, more than 90% of fires in the world are extinguished using such systems.

Sprinkler installations operate on the following principle. Pipelines filled with water or an aqueous solution that is under pressure are installed throughout the room. At certain intervals, locks are installed in the pipes, which act as heat sensors. In most cases, they are designed for temperatures around 70°C.

When a fire occurs, the sprinkler closest to the fire is activated. For example, if the pipes are laid under the ceiling, and the fire started on the floor, then the thermal lock will collapse in 2-3 minutes. All pipes of the system covering the room are connected to a common main line in which the automation equipment is located. The line, in turn, is connected to a pump, which creates pressure in the entire automatic fire extinguishing installation.

At normal conditions, the system is under pressure, while all safety valves are closed. When a fire starts, the thermal lock begins to heat up. The design of the lock consists of a glass flask filled with a special substance and a valve plug.

When heated, the substance in the flask expands and, when it reaches a certain temperature (which is determined by the brand of the lock and the type of substance), it destroys the glass shell. The valve plug is pushed out of the pipeline, and water immediately begins to flow onto the fire.

Automatic sprinkler fire extinguishing systems are good because in a fire, only those locks near which there is a fire are destroyed. This significantly saves water consumption and allows you to protect from it other materials that the fire did not reach.

Although the water in the system is under pressure, its supply soon runs out, since after opening even one or two locks, a significant amount of extinguishing agent falls on the fire. To ensure that fires are extinguished, pressure sensors are installed in the pipelines. They record its decrease, which inevitably occurs after the destruction of the thermal lock, and send a corresponding signal to the control unit.

The unit starts the main pump or turns on the backup pump if the first one fails. The operating time of the pumps is usually from half an hour to an hour. One thermal lock can cover an area from 9 to 16 m².

Despite general principle operation of thermal locks, sprinkler systems can differ from each other in many parameters. For example, they can be coated with a special compound that protects them from corrosion, or made of fire-resistant material. The dimensions of sprinklers are of great importance, as well as their scope of application - systems for offices and warehouses are very different from each other. Modern sprinkler systems are compact and hardly attract attention with their appearance.

For objects that do not have heating, the use of water in automatic fire extinguishing installations makes no sense due to its possible freezing. In these cases, compressed air is supplied to the sprinklers, which presses on the safety valve flap. The water is located higher in the pipes and is protected from “ air lock» special valve. The main reservoir with liquid is located in a heated room. In addition, the system additionally includes a compressor to maintain air pressure. Otherwise, the principle of operation of such a sprinkler system is identical to a system that operates only on water.

Speaking about the advantages of fire sprinkler systems, it is worth mentioning their disadvantages. Let's imagine that a fire broke out in a warehouse for petroleum products or other flammable liquids. In this case, the fire will spread quickly enough, without waiting for each thermal lock to operate.

How to protect materials? To do this, you should use deluge automatic fire extinguishing systems, which are also called flood systems. The principle of their operation is to use special fire sensors located throughout the entire area of the room. The system valves do not open due to destruction from heat, like sprinklers, but at the command of the control unit.

Having received information from the sensors about the start of a fire, the controller opens all valves regardless of in which zone of the facility the fire started. The room is completely flooded with water or special solution, preventing the flame from spreading to neighboring objects.

For guard material assets and at the same time, to effectively extinguish a fire, special installations are used that combine the features of sprinkler and deluge fire extinguishing systems. They are also called pre-action systems, and represent one deluge valve on the common fire extinguishing line, and classic sprinkler valves “in the field”. In addition, thermal sensors are installed in the room, set to a value lower than the temperature of destruction of thermal locks.

In its normal state, the system is not filled with water, unlike sprinkler systems in their pure form. When a fire occurs, the sensor of the deluge system is activated first, since its response temperature is lower than that of sprinklers.

This sensor opens the deluge valve in the common line, causing water to enter the system but not pass beyond the sprinklers. If the fire is not detected during this time, or if there is no time to extinguish it with primary means, the temperature will continue to rise and the destruction of the sprinklers will begin. If the fire is extinguished in advance, extinguishing large volumes of water will not be required, and this will save property.

To avoid possible consumption water and damage to material assets, additional protective elements can be added to the deluge valve system, for which different conditions triggering. Quantity and type protective elements determined by the safety requirements at each specific facility. Thanks to this equipment, you can get reliable system fire extinguishing systems with flexible settings.

For example, pre-action installations are often used in libraries, storage facilities or museums, where water can completely destroy existing valuables. Also, in these systems, additional equipment is installed to create finely atomized water, which cools the fire in the same way as ordinary water, but otherwise acts as a non-flammable gas and does not harm paper or paintings. The extinguishing process is controlled by temperature sensors, which, when it drops to a predetermined value, completely shut off the water supply.

If the fire is not completely extinguished and the temperature begins to rise again, the automation restarts the pumps. Such systems, already more advanced, operate without human intervention and are called cyclic. They are especially valuable because they can be used to protect storage facilities of harmful and toxic substances, where the constant presence of a person is undesirable or excluded. Water or foam is used as a fire extinguishing agent in such systems.

Conventional sprinkler or deluge installations can also use foam. This requires special equipment for foam formation: a reservoir for foam concentrate, a dispenser for mixing the concentrate with water, as well as valves, electric drives and a control and automation system.

A more advanced automatic fire extinguishing installation is a system using finely sprayed water. The water has this name because it is supplied under high pressure through very narrow nozzles. Thus, water enters the combustion zone in the form of tiny droplets and displaces oxygen more effectively.

Water can also be mixed with non-flammable gas, making the extinguishing process even faster. The equipment for such systems is more complex than for conventional sprinkler or deluge installations, but these costs are offset by the smaller reservoir volume and lower water flow. In addition, high extinguishing speed significantly reduces material damage from fire and water.

Finally, automatic gas fire extinguishing installations use non-flammable gases as the main substance - nitrogen, carbon dioxide, some inert gases, etc. Such systems are used where the use of water can cause even greater damage than the fact of the fire itself. The disadvantage of such systems is the strict requirements for the evacuation of personnel, since the gases block the access of oxygen not only to the fire, but also to people. A type of gas installations are powder systems, which instead of gas use a mixture of dry, non-combustible materials. Most often they are used to extinguish closed electrical installations, the use of water in which can lead to a short circuit.

The legislation of the Russian Federation obliges property owners to equip them with automatic fire extinguishing means, the options for which are determined by the purpose of the building and the potential damage that may be caused by a fire.

For some premises, the rules are limited to the requirement to install fire panels with the simplest means of protection, but for many facilities, especially in industry, automatic fire extinguishing installations are required. Unfortunately, they are not always installed as required by regulations.

Some property owners do not have the means for this, others buy cheaper and unreliable installations. The worst thing, and this happens quite often, is when owners deliberately do not use protection, believing that the fire will not affect them.

Despite the fact that the introduction of automatic fire extinguishing systems at critical facilities has long been enshrined in law, there are still designers and property owners who stubbornly refuse to spend money on it. They expect that the fire will bypass them, however, as often happens, it comes precisely to those who did not take care of their safety in advance.

This is why the design of a fire extinguishing system must be approached from the opposite direction, assuming that a fire will occur. And it will not just happen, but will be as strong as possible to destroy all buildings and valuables. Based on this, you should choose the optimal composition of the fire protection system. Typically, developers are guided by the following criteria:

Safety for people;
Security for property;
Extinguishing speed;
Difficulty in installation and maintenance;
Environmental Safety;
Price.

After this, the study of the characteristics of a particular object begins. Let's consider the choice of an automatic fire extinguishing installation for a building where many paper documents or similar valuables are stored - a museum, library or archive.

Implementation of a fire extinguishing system in libraries and similar facilities

Modern technologies involve storing information on special media. Thousands of pages of information easily fit on a small memory card that weighs less than one gram. However, there is a lot of information that is forced to be stored on paper. These can be various archival documents that must be stored for several years, but they are in no hurry to convert them into electronic form.

This could be money in the bank or books in the library. Finally, many paper media are no less historically valuable than the information they contain. Imagine an original work by Shakespeare or Pushkin, reflecting the spirit of those times, and the significance fire protection will increase significantly. This category also includes paintings and, in general, most of the valuables stored in museums.

All this makes libraries, banks, archives, museums and similar facilities those premises where the installation of automatic fire extinguishing systems is strictly mandatory. In addition to actually fighting the fire, they are subject to strict requirements regarding the speed of response and the type of fire extinguishing agent.

The speed should be kept to a minimum once a fire is detected, and the extinguishing agent should not damage storage media. This is especially true for repositories of historical documents, since even a slight change in temperature or humidity can lead to destruction of the paper.

Thus, listed factors form two basic requirements for automatic fire extinguishing installations at facilities of this type:

The fire extinguishing agent must extinguish the fire extremely quickly and prevent its spread;
The fire extinguishing agent must not cause damage to material assets.

From these requirements it is clear that water, such a popular means of fighting fire, is unsuitable for use at facilities of this type. The reason is clear: under the influence of water, the paper gets wet, just as the ink on it gets wet and spreads. As a result, you can lose not only information, but also the medium itself, which is completely unacceptable for storing valuables. In addition, water can trigger complex chemical processes, in which destructive substances can penetrate deep into even papers untouched by fire and water, which will also lead to their loss in the future.

More attractive fire extinguishing agents are foams or powders, but even these, upon closer examination, are excluded from the list of candidates for extinguishing. The fact is that they all fight fire through chemical reaction. At the same time, the powder does not distinguish what needs to be extinguished, and has the same effect on both the fire and other substances in the room. Another disadvantage in favor of aerosols is the high starting temperature of these substances. Sometimes it can be so high that they themselves can become sources of paper fire.

It is also undesirable to use systems based on aqueous salts of metals of the first group of the periodic table - sodium or potassium. They affect fire chemical methods even more active than aerosols and powders, however, their effect on other substances is extremely strong. In addition, they cause inflammation of the eyes and skin people, which forces them to abandon them when protecting libraries and repositories of valuable materials.

As a result, non-flammable gases are best suited for the role of fire extinguishing agent for objects of this purpose. True, this method has its opponents, who claim that gas installations only cope well with open fire and do not detect smoldering sources well. Moreover, previous legislative norms required that facilities have additional installations for producing finely atomized water to ensure the extinguishing of any fire. This approach, indeed, makes it possible to cope with fire in all cases, however, the risk of damage to material assets is also quite high. Developers had to implement these systems in order to sacrifice several documents in order to avoid re-ignition.

Fortunately, new automatic gas fire extinguishing installations are free of the disadvantages of all their predecessors. Special chemical compositions allow the fire extinguishing agent not to remain on the surface of the materials, but to penetrate into the smallest pores deep into the paper. Thus, smoldering documents are detected and eliminated at an early stage, and re-ignition does not occur. This is especially important for thick stacks of paper - for example, for bank vaults, since fire likes to “get stuck” in the thickness of documents.

Conclusion

This article examined the main automatic fire extinguishing installations and the principles of their operation. The criteria for one or another choice of fire protection systems were also presented here. Remember that when choosing many options for fighting fire, you should first of all focus on safety. It is important to take into account both the safety of people and the safety of material assets. The same type of installation can play a decisive role in extinguishing a fire in one case, and cause even greater property damage in another. Designing automatic fire extinguishing systems is a complex and responsible process that requires comprehensive comprehensive consideration.

A fire extinguishing installation is a group of means that can be used to extinguish a fire while releasing fire extinguishing agents. Such installations can be manual or automatic. Let us dwell in more detail on the second type of installation, which at the same time operates as a fire alarm, that is, it gives a signal if a fire is detected.

Extinguishing a fire using improvised means or by the fire brigade has long been no longer a relevant method of fighting fire at large facilities. As the main means of protection against fire, they use automatic fire extinguishing installations, which differ from each other in design, dimensions and type of fire extinguishing agent.

Therefore, when choosing a fire extinguishing installation, several factors must be taken into account. Such a system should monitor the situation at the site, notify people about the start of a fire and begin to extinguish it independently. These requirements apply to residential premises, offices, warehouses or industrial enterprises.

One of the popular fire extinguishing systems is the installation of installations that include a GSM-band alarm system. This means that the equipment not only monitors the fire situation and begins to extinguish the fire automatically, but also informs the person about this by calling or sending an SMS to a regular mobile phone.

After receiving a signal from the sensors about a fire, the system can be activated in two ways:

Automatic, in which the fire valves open and the pump starts when a signal is received from the controller in the system control unit;
Manual, in which fire-fighting equipment is started by controls on the operator’s console or directly in the control panel at the facility.

As for the supply of fire extinguishing agent, in this case there are also two options for the fire extinguishing system:

Supply of fire extinguishing agent directly to the fire zone;
Spraying a fire extinguishing agent over the entire area or volume of the room where a fire is detected.

Fire extinguishing agents

Fire extinguishing agents are the basis of any fire extinguishing installation. Depending on the purpose of the object and the type of protected materials, the substances may be different. Let's look at the most common of them.

Water. Water is the most proven and popular means of fighting fire. It is usually used in sprinkler systems, that is, in those where it is supplied only to the source of the fire. This method is very effective (more than 90% of fire extinguishing installations worldwide), although it requires large volumes of water and, accordingly, additional equipment for its storage and pumping. Water is used to extinguish materials that are easily ignited. At the same time, water affects not only the fire, but also other materials and valuables located in the room. Therefore, its use in libraries, museums and other similar buildings is inappropriate, and sometimes even prohibited.

Another disadvantage of water fire extinguishing installations is their low efficiency - only about a third of the water consumed is actually involved in the extinguishing process. To avoid unnecessary costs, a fire extinguishing installation with water mist technology is required.

This method combines the functions of ordinary water, which effectively cools the burning surface, and non-flammable gas, which blocks the access of oxygen to the combustion zone. In this case, water savings amount to up to 30%, and the speed of fire localization and extinguishing is higher than when using classical methods.

Powders and foams. These substances do not require as much consumption as water, therefore they are widely used in residential and administrative buildings, in factories, warehouses, electrical installation rooms and many other facilities. Often their installation is mandatory requirement, established by law.

Fire extinguishing powders and foams quickly absorb large amounts of heat, quickly cooling the burning surface. In addition, they form a thin film that prevents oxygen from reaching the fire. The disadvantage of fire extinguishing installations using these materials is their short shelf life.

Non-flammable gases. Fire extinguishing systems based on non-flammable gases supplied by our company have undeniable advantages. These substances (carbon dioxide, nitrogen and others) do not affect materials and property, since their influence is limited to the displacement of oxygen from the combustion zone. In addition, they do not freeze at low temperatures and easily erode after a fire. They also have a drawback, and it must be taken into account. It involves the need to quickly evacuate people before starting extinguishing, since oxygen is “cut off” not only to the fire, but also to people.

Let's try to divide such settings into different groups, and let's look at the pros and cons of each group. How automatic fire extinguishing installations are classified is indicated in the following diagram.

What substance is used to extinguish fire?

Design

Fire extinguishing method

Installation launch method

sprinkler

By volume

Manual start

Deluge

By area

Automatic start

Modular

Locally

Combined starting method

Powder

Aggregate

Aerosol

Let's take a closer look at each type of fire extinguishing agent.

Fire extinguishing installation using water and foam

Similar fire extinguishing systems can be sprinkler or deluge, it depends. what sprinklers are used in them. Drenchers are ordinary sprinklers that have a directional effect.

A sprinkler differs from a deluge in that it contains a glass bulb that prevents the extinguishing agent from escaping. It also contains a special alcohol impurity. If the flask heats up and reaches a certain temperature, it begins to collapse, as the alcohol mixture in it expands, and thus water or foam has free access and comes out.

In addition, sprinkler equipment is classified based on what the distribution pipelines are filled with, as well as those responsible for power supply. So they are water-filled, air-filled and water-air.

Air and water-air systems are used when it is considered possible that the temperature in the area where the pipelines are laid will decrease, and also in order to inside no ice would form.

The difference between foam fire extinguishing and water extinguishing is that it contains a foaming agent, which is connected to the pipeline system. Foaming agents are of the following types:

In the form of metering pumps that supply a foaming agent into the pipeline opening;
In the form of automatic dispensers that contain a Venturi tube and a plunger reducer (if the consumption of water resources increases, the pressure in the tube increases, and the reducer begins to supply an additional amount of foam);
In the form of ejector-type foam mixers;
In the form of dosing tanks that take advantage of the pressure difference created by the Venturi tube.

One of its advantages can be noted that water fire extinguishing It is safe for humans, and its fire extinguishing agent is also available in unlimited quantities, unless of course the system is connected to an external water supply network.

In this case, it is necessary to take into account the presence of some restrictions: fire extinguishing installations must be supplied with water in accordance with the first reliability category. This means there must be two different sources, from which water must flow to pumping stations. If it is impossible to organize such an input, then it is necessary to provide a storage facility that will contain the fire extinguishing agent, and in this case water.

The main disadvantage of the water and foam system is that the equipment and structures are quite cumbersome; in addition, it is necessary to carry out welding work during pipe installation. In addition, it is necessary to design and install a booster pumping station if there is no required pressure at the equipment inlet.

But it is still hardly possible to find an alternative to this method of extinguishing fires if the system needs to be installed at a large facility, such as, for example, a multifunctional center, a hypermarket, or in a building where a large number of visitors are constantly present.

This type is worth talking about especially. It has all the advantages of water fire extinguishing, but does not have some of the disadvantages. So, if a regular sprinkler is activated, then drops with a diameter of up to two millimeters and with a fairly significant mass are formed.

This leads to the fact that drops quickly fall down and only one third of them somehow contribute to extinguishing the fire. Why are so many water resources being wasted? If a fire is extinguished using finely sprayed water, then the droplets have a diameter of no more than one tenth of a millimeter. They fall quite slowly, which leads to the formation of so-called “water fog.” Most of the water resources are used to cool structures and put out fires.

This leads to the fact that water is consumed three times less, which will eliminate the need to install expensive pump equipment, reduce the diameter of the supply and distribution pipelines. Such a system will also help prevent unpleasant consequences that arise if a large amount of water is used. Such consequences may be corrosion, damaged equipment or material assets.
The fire extinguishing system, which uses finely sprayed water, can be modular and centralized (aggregate).

If the equipment needs to be installed in a small separate room, then it is better to use a modular system, which consists of a vessel that contains the fire extinguishing agent), a cylinder that contains the working gas to form a gas-liquid mixture, and a distribution pipeline that has nozzles - sprinklers.

Such equipment is installed in premises with an area of more than a thousand square meters. Aggregate installations consist of separate sections, which in turn consist of several modules. They do not contain starting cylinders containing working gas. Modules get it from distribution devices through standard carbon dioxide fire extinguishing batteries.

The advantage of such a system is that it is not connected to power sources, since it operates this installation based on hydraulic principle.
The disadvantages include the fact that it may cost less than similar gas installations, but still its cost is much more than the price of a powder system. In addition, if you use finely sprayed water over a large area, it will not be an economical solution.

Designing such installations is also not so easy; it causes certain difficulties. Since there is no full-fledged regulatory normative documents, That technical specifications, are developed for any object and are agreed upon with representatives of the Ministry of Emergency Situations.

Such a system is installed when the powder, water or foam used in other systems can harm equipment located in the fire area.
Such systems have the advantage that they completely lack side effects on the property located there, unless, of course, the ventilation system is designed correctly.

The extinguishing agent is removed from the fire area very quickly. Gas fire extinguishing is based on the following principle: the oxygen concentration decreases as non-flammable gas begins to flow into the area. If this gas is liquefied, then leaving the cylinders it leads to a decrease in temperature. The fire extinguishing system using gas differs from others in that it does not freeze, and it is also not afraid of heat. It can work properly both at minus forty and at plus fifty.

The disadvantage of such systems is that the fire extinguishing gases used can be toxic, which means that before using them it is necessary to first evacuate people who are in a dangerous area, and the object itself must be equipped with a set of self-defense equipment (self-rescue kits, gas masks).

In addition, such a system must necessarily have equipment that would prevent the system from turning on if the doors are open. At the same time, it is necessary to provide special openings that will be used to dump overpressure in the protected area when a gas extinguishing agent is supplied. And the main disadvantage is its overpriced. To protect a small area, you need to have a large amount of gas, which is stored in cylinders or an isothermal tank.

Mostly gas fire extinguishing used to protect relatively small room, having high degree tightness, which contains expensive high-tech equipment or other property that could be damaged by other fire extinguishing agents.

Depending on how the fire extinguishing agent is stored, powder fire extinguishing can be modular and centralized. Modular powder fire extinguishing has become widespread. This is due to its some undeniable advantages. Such a system consists of vessels of various shapes, which contain fire extinguishing powder and gas-generating elements. This makes it possible to install such a system in almost any room. They can be installed in closed spaces - cable structure, behind a pseudo-structure, in a cabinet containing equipment, as well as in other similar places.

If the gas-generating mixture is heated to critical temperature when the system is triggered, the propellant gas begins to be intensively released in the module. This leads to the opening of the shell of the modules, or the powder is supplied using a nozzle. The module is triggered in the same way if an electrical signal is supplied, if the system has an electrical start. When released, the powder leads to the formation of a dust-air mixture. This mixture gradually drops, and thus oxygen ceases to flow into the fire area, and this leads to its blockage.

Another advantage of such a system is that it allows you to extinguish almost all types of fires, even if it concerns high-voltage electrical equipment.
This does not apply only to those materials that can burn in an oxygen-free environment. Another advantage is the price powder systems fire extinguishing They are lower than all other installations.

Now let's turn to the disadvantages of powder plants. First of all, they are dangerous for humans, because if a large amount of powder enters the respiratory system, this can lead to suffocation. Also, if the modules work, then perhaps nothing will be visible because of the powder cloud. That is why such installations are rarely used in a public place, or in a room where a lot of people are constantly present. If the powder for a long time is in modules, it begins to deteriorate, which is why their shelf life is limited. In addition, if the installation is triggered, then after the fire is extinguished, it can be difficult to remove the fine powder.

This system is based on the use of fine powder. When some solid chemical compounds are burned, an aerosol is formed, that is, when these substances are burned, this leads to the formation of a jet, which includes a hot mixture of gases and trace elements.

By filling all the free space, they help extinguish the flame. That is why such installations are not used in rooms where explosive substances are located. If an aerosol fire extinguishing system is activated, the temperature and pressure in the gaseous environment rise and visibility sharply decreases. This is why people urgently need to leave the premises before the generator turns on.

It should be noted, however, that the effect of the aerosol on the human body is not harmful, although it has great fire extinguishing ability.

How different types of fire extinguishing systems are used

Form of extinguishing agent	How to extinguish a fire	Where can I apply the installation?	Where the installation cannot be used
By water	Superficial, volumetric (if fire extinguishing is used using finely sprayed water)	To eliminate class A and B fires. Installed in warehouses, supermarkets, hotels, premises where flammable natural and synthetic resins, plastics and so on are produced.	In rooms where substances are stored that emit heat, flammable or toxic gases when interacting with water. This applies to some metals and organometallic compounds, metal carbides and hydrides, hot coal and iron. Also, the sprinkler and deluge system is not used to extinguish high-voltage electrical equipment.
Foam	Volumetric, superficial and local	Most often used in the petrochemical industry to extinguish fires involving flammable and combustible liquids. There are also other areas of application: reservoir of flammable substances or products oil industry, which are located both inside the building itself and outside, in hangars, in warehouses where solvents, alcohols are stored, in the holds of sea vessels, and so on.	This unit should not be used if substances that, when interacting with the foam, release toxins, have ignited.
Gas	Volumetric fire extinguishing method	To extinguish fires of varying degrees of danger if high-voltage electrical equipment catches fire. Their main advantage is that they, one might say, do not cause damage to the object they protect. As a rule, they are installed in a computer center, in libraries, archives, museums, cash depositories, some warehouses, and so on.
Powder		Apply when spilled flammable liquid or gas leakage from equipment located outdoors. In addition, they are used in oil loading and pumping facilities, aircraft hangars, and so on. Effectively extinguish fires in electrical installations where there is high voltage.	It should not be used if a room has caught fire in which there are materials that tend to burn even in an oxygen-free environment, which spontaneously ignite or smolder in the substance (warehouse with sawdust, cotton, grass meal, foam rubber...), or metals such as sodium, potassium, magnesium, titanium...
Aerosol	Volumetric local and surface	To eliminate fires of the first and second degree of complexity. As a rule, such a system is used if electrical equipment and other energy facilities catch fire, and also to protect vehicles, oil industries, transport compartments of ships and so on.	They do not completely extinguish a fire if fibrous, porous and other combustible materials that are capable of spontaneous combustion and smoldering in the layer are burning; technical substances, as well as their mixtures, polymer materials that are capable of smoldering and burning in an oxygen-free environment; metal hydrides; metal powders

And finally, it should be noted that in accordance with the standards, in each specific facility, a licensed design organization decides which fire extinguishing system to install, how to extinguish the fire, and what fire extinguishing agent to use. This takes into account fire danger And Chemical properties substances that are produced, stored and used. It is also necessary to take into account what features the protected equipment and building structures have.

And yet, there is no need to make the final choice of fire extinguishing systems without taking into account how much it will cost to install fire equipment. You also need to consider how compatible engineering systems premises and systems fire safety. And of course, there is no need to bypass calculations of how much it will cost Maintenance and routine maintenance, which often costs more than installing the entire system.