Air ducts are the most important element supply and exhaust system smoke removal. The operation of such a system, as a rule, occurs in fairly harsh and extreme conditions, under the influence of gases whose temperature reaches 400C°. In addition, the chemical composition of the removed air masses can be quite aggressive. That is why the requirements for smoke exhaust ducts are standardized.

Air ducts for smoke exhaust systems are metal boxes, rectangular or round section, which are mounted both in the walls of buildings and on the outer surfaces of the walls of structures. Sections of these products can have two types of connections: welded or seam.

The welded connection of air ducts is regulated by the requirements of SNiP 2.04.05–91, SNiP 3.05.01–85, as well as VSN 353–86 standards.

The material used for air ducts is low-carbon and galvanized steel. In accordance with GOST 19904–90, the thickness of the wall of the air vent made of cold-rolled steel should be 1.0–1.4 mm, the thickness of the air channels made of hot-rolled sheet steel 1.5–2.0 mm. In some cases, the thickness of smoke exhaust ducts can be up to 3 mm.

Acceptable classes of air ducts

• The air ducts most suitable for organizing smoke exhaust systems in industrial, civil and administrative buildings are produced with the markings “N” and “P”, i.e. normal or dense.
• Air ducts of class “N”, according to SNiP, are allowed for use in premises with a minimum level of fire hazard, having categories “B” and “G”. In class “H” air ducts, minimal leakage is allowed air mixtures during transportation.
• Air ducts of class “P” have high reliability of connections and a tight seal. According to the requirements of SNiP, such elements for transporting air masses can be used in premises of class “A” and “B”, i.e. with increased explosion hazard and release of combustible dust into the air, igniting at temperatures of +28C°.

Fire protection of air ducts

The fire resistance of smoke exhaust ducts is also strictly standardized. It should be at least 120 minutes at a temperature of transported gases of 400C°. Fire protection of air ducts is ensured by applying special mixtures and compositions, as well as fire-resistant roll materials, to their surface.

Today, there are several ways to create protection for shafts and channels of smoke exhaust systems from thermal and chemical influences.

1. Mounting thermal protection systems are installed on air ducts using adhesives and special fasteners.
2. Fire-resistant mixtures, represented by special plaster compositions, which effectively cover all elements of air ducts and fittings.
3. Heat-resistant rolled materials.
4. Coating gels and special compounds with the addition of a foaming agent.

Important:
On modern construction market not so long ago, fire-retardant paint Pirex appeared, which will effectively protect air vents from burning out for an hour, at gas temperatures up to 120C°.

One of the most common materials for creating a thermal barrier for smoke exhaust air ducts is Isovent fire protection, which is a high-quality roll covering made of basalt fiber covered with foil. The main advantages of this material include:

• Low cost.
• Easy to install.
• Possibility of cleaning.
• Possibility of use in wet areas.

Installation of Isovent fire protection to air vents is carried out by applying a specially developed adhesive composition to the product and fixing it to it using ordinary wire.

Stages of fire protection work

All work on thermal protection of air ducts of the smoke exhaust system can be divided into several stages:

1. Development of a project with a complete list of activities.
2. Coordination of design documentation with fire authorities.
3. Obtaining an expert opinion on the work.
4. Fire protection of air channels.

After completing the work, the contractor company must issue a certificate to the customer, with signatures of representatives of fire supervision, confirming compliance with regulatory documents and technical specifications.

For another way to protect air ducts, watch the video:

Features of installation of air ducts

The performance of the smoke protection system directly depends on the quality of installation of air ducts. Installation of smoke exhaust ducts is carried out using stands, hangers and other fasteners, which are specified in the design documentation.

All fasteners are made of steel. There are no requirements for treating fastening elements with fire-resistant compounds, but it makes sense to cover these products with fire protection, since burning through the air duct fastening will inevitably lead to the collapse of the entire smoke exhaust system.

• Smoke protection air vents with a round cross-section are connected to each other using flanges made from a steel strip, and those with a rectangular cross-section are connected from a tire.
• When installing shafts and channels, all flange connections are sealed with asbestos cord so that when the nuts are tightened, there are no gaps left between the flanges.
• Fastenings of horizontal sections of air ducts are installed at a distance from each other of no more than 6 m. Fastenings of vertical sections of air ducts are made at a distance from each other of no more than 4 m.

After the installation of the smoke exhaust system channels is completed, the equipment is installed and the air ducts are treated with a fire-resistant mixture.

Advice:
Air ducts of smoke exhaust systems are the main structures that ensure the safety of life and health of people in the event of a fire, preventing them from suffocating by combustion products. That is why the installation and fire protection of air ducts should only be carried out by professionals who have all the permits for this.

In this article we will describe about design features of these systems and briefly touch on the topic of requirements fire safety in relation to them.

Supply and exhaust smoke removal systems.

Air ducts are part of the supply and exhaust smoke removal system and represent a set of ventilation pipes. Through them, smoke and harmful chemical compounds of combustion products that occur during a fire are removed from the premises of the building, which makes it possible to evacuate people from the room with the source of the fire.
Smoke removal systems are used in both residential and industrial buildings.

Being in a room with a fire, the air ducts are in extreme conditions. They are exposed to high temperatures reaching 400 0 C and the chemically aggressive composition of the removed combustion products. All of the above can lead to deformation and damage to the integrity of the air duct housing. Violation of integrity, in turn, can lead to the rapid spread of flame into adjacent rooms and will make the removal of smoke and combustion products ineffective.

In this connection, the requirements for fire resistance of air ducts are standardized. At a temperature of removed combustion products of 400 0 C, the fire resistance limit of the air duct must be at least 120 minutes.

What are steel air ducts?

Air ducts are produced in the form of metal boxes of rectangular or round cross-section.

Installation of air ducts is carried out both inside the walls of buildings and on the external surfaces of walls and interfloor ceilings. Sections of air ducts are connected using two types of connections - welded or seam. The regulatory documents for welded joints are SNiP 2.04.05–91, SNiP 3.05.01–85 and VSN 353–86 standards

For the manufacture of air ducts, low-carbon or galvanized steel is used.

When producing smoke exhaust ducts, it is taken into account that the thickness of the air duct wall should be:

• For air ducts made of cold-rolled steel 1.0 - 1.4 mm.
• For air ducts made of hot-rolled sheet steel 1.5–2.0 mm.

Air duct classes.

There are the following classes of air channels: N (normal) and P (dense). These channels are used in smoke removal systems of civil administrative buildings and industrial enterprises.

• The use of air ducts of class H is allowed in premises of fire hazard classes B and D.
• The use of class P air ducts is in rooms of fire hazard classes A and B. The use of these air ducts is expected in rooms with increased explosion hazard, the release of explosive dust into the air, flammable at temperatures of +28C°. Structurally, class P air ducts at the joints are highly reliable and have a tight seal.

Fire protection of ventilation and smoke removal systems.

C.O.K. N 7 | 2005 Category: HEATING AND DHW
"Regional pipe and furnace company "GALS""

Comparative analysis of smoke removal systems.

Currently, autonomous heating systems are becoming increasingly widespread, which, as a rule, use boilers with low flue gas temperatures. Issues of increasing efficiency and reducing emissions harmful substances are becoming more and more relevant. Another important issue is the safety of soot fires in smoke removal systems of fireplaces and other solid fuel heat generators. As a result, the main factors of gas removal have undergone significant changes.

For modern systems smoke exhaust systems are characterized by:

lower flue gas temperature;

high content of water vapor (due to the transition to liquid or gaseous fuel);

heat dew point (due to high CO2 content);

wide range of flue gas temperatures due to controlled operating technology of heating systems.

In this regard, old (brick) smoke systems become unsuitable for use in modern boiler houses, since:

insufficiently rapid heating of the chimney walls leads to the formation of acid precipitation in the chimney trunk, destroying it;

the cross-section of the smoke channel is not always commensurate with that required for the system;

soot formation increases due to surface roughness.

Taking this into account, the following requirements arise for modern smoke systems:

fire resistance;

acid resistance;

tightness;

quick heating of the chimney walls;

good thermal insulation of the structure;

speed and ease of installation;

smooth channel surface.

Modular chimneys made of ceramics and of stainless steel.

By type, modern chimneys are divided into:

single-circuit (non-insulated) - used as liners in a brick chimney;

double-circuit (insulated) - consist of two layers: internal and external, between which insulation is laid (layer basalt wool), allowing to reduce the formation of condensation;

combined “air-combustion products” (LAS) - used with boilers with closed camera combustion, the internal circuit serves to remove combustion products, and the external circuit serves to supply air to the heat generator. Modular chimneys are simple and easy to install, durable, and aesthetically pleasing, which makes them indispensable when installed with any heat generator.

Technical characteristics of materials used for the production of modular chimneys:

profiled ceramics - thickness 6–14 mm, acid-resistant, heat resistance 1500°C (restores all characteristics after soot ignition);

stainless steel AISI 316 TI (1.4571) - thickness 0.5–2 mm, acid-resistant, heat resistance 1000°C;

stainless steel AISI 316 L (1.4404) - thickness 0.4–2 mm, acid-resistant, heat resistance 1000°C;

stainless steel AISI 304 TI (1.4301) - thickness 0.5 mm, heat resistance 700°C;

mineral basalt fiber ROCKWOOL, fire resistance - 1100°C, chemically resistant, environmentally friendly, thickness 25-100mm.

Main selection criteria

For chimneys boiler houses operating on gas or diesel fuel, it is important to compare systems in terms of acid resistance and gas tightness. For stainless steel systems - according to the thickness and acid resistance of the material inner tube- in descending order of quality indicators: AISI 316 TI (1.4571) AISI 316 L (1.4404) AISI 304 TI (1.4301), as well as by thickness and quality of insulation. The quality characteristics of the chimney are the priority selection criterion.
Ceramic profiled pipe is comparable in acid resistance to the best steels. The use of sealants when gluing the elements of a chimney pipe allows us to ensure a high gas tightness of the system, suitable for conditions with excess pressure. The pipe manufacturing technology is also important, making it possible to make the channel even, without narrowing at the joints.
It should be noted that when operating stainless steel pipes from any manufacturer used with solid fuel heat generators, the question arises about the static stability and deformation of the chimney channel when soot ignites, and the subsequent operation of the chimney system.
In this case, ceramic pipes have an undeniable advantage, although many installers and builders avoid their use, since the time required for installation is greater than for installing a stainless steel chimney.
It is impossible not to note the importance of such a criterion as operating temperature, and, in connection with this, the heat resistance of smoke systems. With the advent of ceramic systems produced by Schiedel on the market in insulated chimney systems, direct competition arose between ceramics and stainless steel as materials for the production of chimneys, and the position of ceramic chimneys has strengthened significantly recently due to the appearance on the market universal system UNI, comparable in price to stainless chimneys, but with advantages when used with solid fuel heat generators.

Let's compare the main systems of chimney manufacturers

Schiedel

The Schiedel company is one of the most famous chimney companies in Europe, founded in 1946 by Senator Friedrich Schiedel in Erbach (Germany). Today, Schiedel belongs to the international concern LAFARGE and is the world's largest manufacturer of ceramic chimney systems. The company has developed many technical innovations.
The basis of the company's product line is ceramic chimney systems made of fireclay. The most versatile chimney insulated system UNI with ventilation consists of three complementary system components:

high-quality inner pipe made of fireclay with the most favorable round cross-section for flow movement, pipe connection by means of a fold for maximum stability and density;

perfectly fitted high-strength profiled insulating boards;

stone shells from lightweight concrete, exactly corresponding given dimensions and having an optimal cross-section of ventilation channels from an aerodynamic point of view, which protect the insulation from moisture.

Stone concrete shells can be equipped with multifunctional channels that serve as ventilation shafts, and also allow cables, antennas, and engineering equipment to be placed in them. Specially designed smoke channel system Schiedel QUADRO not only delivers the combustion air necessary for combustion to the combustion site, but also safely removes combustion products. QUADRO system - The best decision for the removal of flue gases in an apartment building. Schiedel QUADRO - the new gas-air chimney system (in the international designation LAS system) has the most important advantage: energy savings are achieved thanks to the heat exchange process between gas and air.
For installing a chimney in an already built house, Schiedel recommends a chimney system KERASTAR . It provides the perfect combination of a ceramic flue duct, mineral fiber insulation and a lightweight stainless steel shell. The internal profiled pipe made of high-quality ceramics is resistant to burnout, corrosion and acids. Thanks to the connection system using stainless steel crimp clamps, simple and quick installation is achieved. The outer shell has a spectacular appearance, therefore does not require additional finishing. The use of an internal ceramic tube allows the use of solid fuel. Safe distance from flammable building structures is only 5 cm. The company gives a 30-year guarantee on the internal ceramic pipe.
For the reconstruction of brick channels, Schiedel specialists created a system of profiled ceramic pipes KERANOVA , which can be used both for boilers (including those with excess pressure), and for stoves or fireplaces, a special advantage of this system is the ability to insert a consumer at any level, regardless of the chimney elements. A thin profiled wall allows you to reduce the heating time of the pipe and make it comparable to stainless steel systems.

The main advantage of Schiedel ceramic chimneys is their high versatility (the ability to work with any type of fuel and any type of heating equipment, reliability, safety and durability).
Smooth, round inner surface fireclay pipe, high-quality insulation and correct selection diameters guarantee safe removal of flue gases through the roof. Schiedel chimney systems with ceramic pipes are easy to install.

Fire safety certificate from VNIIPO RF for ceramic systems. Certificate of conformity to GOST of the Russian Federation. Sanitary and epidemiological certificate for Schiedel products.

Raab

Raab Joseph Raab GmbH & Cie. KG has a history of more than a century - from its creation in 1898 to the present day. Today the production program of the German manufacturer includes:

single-walled, double-walled flue ducts made of mirror stainless steel with diameters from 80 to 600 mm and a patented Alkon connection system;

noise-absorbing devices;

thermal exhaust gas valves;

flow limiters and combustion air supply valves for all types of heating boilers, block thermal power plants, furnaces with exhaust gas temperatures up to 600°C using gas, diesel and solid fuels.

Raab flue gas exhaust systems are designed for use with: boiler installations; condensing boiler installations; BTES; emergency power generators; on bakery ovens.
Operating modes of Raab flue gas exhaust systems: with overpressure; under discharge.

The main characteristics of Raab flue gas exhaust systems include:

1. Gas density - up to 5000 Pa;

2. The sealing area is 20 times larger than normal joint.
The vertical section is a self-compacting system. In the horizontal section, the elements are pulled together with special clamps;

3. Heat resistance - up to 600°C;

4. Metal seal. There are no seals made of artificial materials (rubber, caoutchouc, etc.), which, as a rule, are much less heat-resistant. Thermal insulation 30 mm made of non-flammable mineral fiber.

5. Speed ​​of installation. There is no need to secure all connections with static clamps - each element is inserted separately, a plastic cover is placed on top, and 3-4 light blows are applied with a hammer in the direction of the joint, as a result of which the conical surfaces of the elements are pressed tightly against each other.

6. Corrosion resistance. All elements of the flue are made of acid-resistant stainless steel grades 1.4404 and 1.4571 made in Germany. Each element has a capillary stopper. Continuous thermal insulation guarantees the absence of temperature changes.

7. Internal diameters of the gas duct are from 80 to 1200 mm.

Fire safety certificate for insulated gas flue DW Alkon. Fire safety certificate for single-wall flue EW/FU. Sanitary and epidemiological certificate for Raab products.

Bofill

Spanish company F.F. Bofill has hundreds of years of experience in the production of chimney pipes. The plant is located in Barcelona, ​​products are supplied only to Spain and Russia. In Russia, the company's chimneys have been successfully used for a long time. The plant's products supplied to the Russian market can be divided into four main categories:

1. Double-walled chimneys

The inner wall of the pipe is made of AISI 316 stainless steel with a thickness of 0.4 mm, and all components are made of AISI 304 stainless steel with a thickness of 0.5 mm. The insulating insulation is made from dense basalt fiber ROCKWOOL 30 mm thick. The operating temperature of a double-walled chimney is 500°C. Short-term heating of pipes up to 700–750°C is possible. System double-circuit chimneys retains all performance characteristics at temperatures up to 500°C. The double-circuit chimney system retains all performance characteristics at temperatures environment down to –50°C. Recommended for use both indoors and outdoors.

2. Single-wall chimneys

Also made of AISI 304 stainless steel, 0.5 mm thick. Working temperature single wall chimney - up to 450°C. Recommended as an insert into a brick chimney and as part of a chimney located indoors exclusively for gas fuel.

3. Enameled chimneys

Enameled pipes made of carbon steel, coated with heat-resistant glaze. Operating temperature - 900°C. Recommended for solid fuel boilers and fireplaces as an indoor connection line.

4. Flexible flues

On the Russian market, the most widely used flexible gas duct is Lisflex, made of AISI 316 stainless steel. They are used in chimneys of strongly curved structures, or as inserts in a brick chimney. Chimneys from F.F. Bofill have proven themselves on the Russian market as one of the cheapest and easiest to install.

The main disadvantage of F.F. pipes Bofill, both single-walled and insulated - narrowing of the pipes at the joint and the absence of single-walled elements made of AISI 316 steel, which limits the use of combined systems (single/double-layer) for diesel fuel boilers.

Baltvent

Baltvent LLC, Kaliningrad, specializes in the manufacture of attachmentsinsulated chimneys, as well as inserts For brick chimneys. The plant's equipment is manufactured by leading companies in the countries Western Europe(Germany, Sweden, Austria). The material of the inner pipe is acid-resistant steel AISI 316 L, 0.5–1.5 mm thick. The diameters of pipes produced by the plant are 80–1000 mm.
It is used as insulation in double-circuit chimneys. mineral wool with galvanized mesh, chemically resistant, environmentally friendly. Special technology expansion of the bells made it possible to produce an internal channel without narrowing an almost ideal shape.
Today, the plant is the first in Russia to begin producing pipes with a diameter of over 1000 mm. A wide range of diameters and thicknesses of the internal pipe made this trademark one of the most common of domestically produced chimneys. For the first time, the stock program includes oval pipes and components for the rehabilitation of brick chimneys. Baltvent chimneys also attract buyers due to their inexpensive price and ease of installation.

Certificate of conformity. Fire safety certificate for insulated flue. Fire safety certificate for single-wall flue. Sanitary and epidemiological certificate for Baltvent products.

Rosinox

Another Russian company successfully moving into the market is Rosinox. The company is based in Klin, Moscow region.
The Rosinox company produces chimneys made of AISI 304, AISI 316 L stainless steel using imported equipment and imported raw materials.
Rosinox chimneys are divided into series insulated - “Thermo” and non-insulated - “Mono”. The insulated chimney lining is made of non-flammable high-density basalt fiber.
High quality socket connections make the installation of these chimneys easy and reliable. The advantages are comparable to chimneys from Baltvent companies.

Certificate of conformity. Fire safety certificate for insulated flue. Fire safety certificate for single-wall flue. Sanitary and epidemiological certificate for Rosinox products.

Trankol

The Trankol plant has solid experience in the production of stainless steel pipes and components for chimneys. In terms of its product line, it is most comparable to F.F. Bofill, but has a seam seam, which undoubtedly limits its use in systems with high excess pressure, although the fit tolerances of both insulated and single-circuit pipes are much better than those of F.F. Bofill. The main products are pipes for large and medium power boiler houses. On gas fuel, diameters are 300–500 mm. Issued single-wall maintenance system and insulated TD. Trankol is one of the first Russian companies, who developed the AutoCAD catalog for design.

Certificate of conformity. Fire safety certificate. Sanitary and epidemiological certificate for Trankol products.

They are used to quickly remove combustion products from premises, ensure the possibility of effective fire extinguishing and clear escape routes for the removal of people.

Such tasks are characterized by high responsibility, since people’s lives and the safety of valuable property or equipment are at stake. Therefore, the requirements for the air channels through which smoke and gases generated during a fire are exhausted are quite strict. The equipment must ensure full performance of its functions and exclude the possibility of failures or malfunctions. The quality, characteristics or other parameters of smoke removal systems are regulated by SNiP, since operating conditions require strict standardization of all elements and components.

Which includes smoke removal means, plays a responsible and vital role. The operating conditions for smoke exhaust ducts are complex and contain an abundance of negative factors:

• Heat

• Presence of aggressive combustion products

An additional factor that has a negative impact on the performance of the system is low load - most of the time the fire duct is idle, which creates the possibility of foreign objects appearing inside the ducts. To effectively remove, redistribute or cut off flows, specialized air ducts are used, the material and coating of which ensure the specified performance at high temperatures (fire resistance determined by SNiP).

From a design point of view, smoke exhaust ducts are no different from conventional ones ventilation ducts, but complex and harsh operating conditions place increased demands on the level of tightness - all channels are installed in the “P” (tight) or “N” (normal) version - for buildings with low level fire hazard or low possibility of smoke.

In addition, taking into account the responsibility and complexity of the operating conditions of the system, the requirements for the material have been increased - welded air ducts made of galvanized or low-carbon steel with a thickness of 0.9 to 3 mm are used (thickness is taken based on the conditions of welding work).

Air ducts made of black steel have a special coating that serves as protection against corrosion and increases the resistance of the material when exposed to high temperatures (fire protection). Welding is carried out using the electric contact method; air ducts made of carbon steel are most suitable for this method of joining materials and provide the greatest density. The parts are connected to each other using flanges.

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

Attention! For rooms with a low degree of fire hazard, channels made of galvanized steel with a seam connection can be used.

Types and characteristics

According to the sectional shape there are:

• Round. They are a round pipe. They are considered more efficient and economical, and provide tighter installation. According to SNiP, when performing design work It is the round types of channels that should be considered first.

• Rectangular. Less economical, have low aerodynamic performance and more high level noise. At the same time, they visually look more compact and fit better into the volume of rooms or corridors.

The most common air ducts are made of black steel - if they have all the necessary characteristics, they are cheaper, which is an important argument in conditions of large industrial enterprise. In addition, the operating conditions of smoke protection systems most often do not imply constant operation. Air ducts made of carbon steel, having a high strength welded joint, are able to provide the required density of the smoke exhaust channel, which eliminates leakage of combustion products.

Fire protection is a coating that reduces the destructive effects of high temperatures on the material. According to SNiP requirements, the surface of air ducts must have a coating that is resistant to the transported medium.

In the event of a fire, the temperature of the exhaust gases can reach high values, therefore, the condition for the operation of channels designed for rooms with a high degree of fire danger is the ability to withstand a temperature of 600 ° C for 0.75 hours (45 minutes). In addition to coating, they are used various materials, stacked with outside boxes that protect the material from external aggressive influences. determined by the level of danger of the premises, as well as the composition of flammable substances present nearby.

Shaped products

Shaped products for smoke exhaust ducts perform the same functions as for all conventional systems - they provide the ability to connect, change direction and branch ventilation ducts. The following elements apply:

• Retraction. Changes the direction of the channel. Can be made in several options, from 15° to 90°.

• Stub. Hermetically closes the end part of the channel.

• Tee. An element for connecting one air duct to another. Installed in a channel gap, there are options for connecting rectangular with round or rectangular lines in all variants.

• Transition. Carries out a longitudinal connection of channels having different diameters or side sizes.

• Cross. Combines transverse threads of air ducts into one network.

• Duck. An element connecting channels that do not coincide with each other along the longitudinal axis. Basically, it is made to order, since it is impossible to provide in advance all possible connection options.

All shaped elements are made in both round and rectangular designs (or in combination with one another). For smoke exhaust systems, shaped elements are subject to the same requirements as straight air ducts - in terms of material and manufacturing method and availability protective coating. The connections of the elements are made with a high degree of density, for which a special fire-resistant sealant is used.

Smoke removal ducts are one of the most critical elements. Difficult working conditions, high temperatures and aggressive effects of combustion products can quickly destroy unsuitable equipment. In addition, most of the time the equipment is idle, which can negatively affect its operation in critical situations. High technical requirements and great responsibility of the system require accurate calculation, the right choice and strict compliance with the requirements of SNiP in relation to all parameters of air ducts of smoke removal systems.

How it works?

When a fire occurs, the greatest danger to human life is not fire and high air temperature, but smoke. Smog can provoke panic, disorient people and cause poisoning. In order to prevent such problems, smoke removal systems are installed in the premises, which can localize carbon monoxide and clean the room from small particles of dust and ash.

Smoke removal system is an important element of fire safety

The smoke removal system (SDS) is an emergency supply and exhaust ventilation system that creates conditions for the evacuation of people in case of fire. The smoke protection system is part of the overall set of fire safety measures.

When triggered fire alarm Fire ventilation is turned on. The system begins to actively remove combustion products and smoke from the source of fire, as well as prevent their spread to other areas of the room. Pressure fans direct clean air to fire exits, main exits, stairwells and elevators.

In accordance with building regulations, such installations must be installed in high-rise buildings (more than 10 floors) with fire safety class - B, rooms without natural ventilation, underground structures, prisons, hospitals and other institutions in which a large number of people are concentrated.

The smoke removal system performs the following tasks:

The fire ventilation system operates according to the laws of physics: cold air goes down to the bottom of the room, and warm water goes up. Diversion equipment warm air will help curb the rise in temperature and reduce the negative impact of smoke on the human body.

The smoke removal system is an expensive complex, it specifications and expedient structure require special design.

Types of smoke removal systems: static or dynamic ventilation

Today, all smoke removal systems can be divided into static and dynamic complexes.

At static smoke removal an emergency shutdown of ventilation occurs. At the same time, the smoke does not “pass” to other areas of the room. This system is the most primitive and affordable. In fact, smoke removal as such does not occur; all smoke is localized in one room.

Dynamic system designed to remove smoke and fumes, as well as to influx fresh air. The operation of the complex is based on the use of fans that “pull” combustion products outside the room.

Dynamic complexes can operate on one fan operating alternately in different directions (smoke extraction or fresh air supply), on separate air supply and air supply fans, or on a combination of two axial fans.

The choice of smoke removal scheme depends on the design features of the building and the feasibility of implementing a particular project.

Based on the type of control, SDS are divided into automatic and semi-automatic systems.

Automatic smoke removal is associated with the facility’s security system, installation automatic fire extinguishing and fire alarm.

It is advisable to equip buildings equipped with a large number of equipment and engineering systems with an automatic smoke removal system. Complete system fire extinguishing and smoke removal virtually eliminates the risk of fire and fire spread, giving a signal about the slightest equipment breakdown

Elements of the smoke removal system

Smoke removal is carried out through existing ventilation shafts, the inner surface of which is coated with a fire retardant compound. However, the use of separate communications with special fans and air ducts is considered more effective.

The dynamic smoke removal system consists of the following main elements:

Smoke extraction fans- large heat-resistant units with increased power. Minimum air flow - 20000 m3/hour. Smoke extraction fans are capable of operating at very high temperatures.

The fan pumps out smoke and combustion products from the fire site. Some fan models perform two functions alternately: supply clean air and smoke removal. Smoke extraction fans are mounted on the roof of the building.

Air boost fans create overpressure on staircases, in elevator shafts and lock vestibules, excluding their smoke.

No less important element smoke removal systems - fire dampers. There are four categories of fire dampers:

Smoke hatches are mounted on the roofs of buildings and automatically open when a fire occurs. Rooflights can be used as such hatches, which under normal conditions perform the functions of lighting and ventilation.

Ventilation ducts for smoke removal(shafts) - large cross-section air ducts made of black steel. The thickness of the material must be at least 1.2 mm - this increases the resistance of smoke exhaust ducts to high temperatures.

Automatic systems are equipped with smoke detectors that are triggered when a fire appears and send a signal to turn on fans and fire dampers.

The principle of operation of the smoke removal system

Let's consider the working cycle of the smoke removal system step by step:

1. There is a fire in the room - the smoke detector is activated.
2. The signal from the sensor is sent to the control station.
3. The general ventilation system is automatically switched off and all fire-retarding valves are closed.
4. In the fire zone, a valve opens in the smoke exhaust system to remove smoke.
5. The smoke exhaust fan and the air supply fan are turned on at the same time.

Important! The smoke removal system is designed to “pump out” smoke from one source of fire. That is, all smoke is removed from one grille of the system (conditionally one, since each zone may have several grilles). On other floors and areas of the room, the fire dampers of the system will be closed

Calculation of fire ventilation system

Design of a smoke removal system

The requirements for the design and maintenance of smoke removal systems are quite high, so this work must be performed by design engineers. The company’s specialists will calculate smoke removal, prepare a detailed design, install and configure equipment, and also test the system.

When calculating and developing a smoke removal scheme, the following room parameters are taken into account:

• building construction material;
• number of storeys of the building;
• emergency evacuation plan;
• the state of the existing ventilation system;
• smoke permeability of the room;
• the presence and location of windows in the building;
• condition and material of insulation;
• type of interior and facade finishing.

All factors that can affect the speed of spread and amount of smoke during a fire are taken into account

The smoke removal project is drawn up based on building codes and rules, which clearly state minimum requirements to the fire ventilation system. The main document regulating the design procedure is “Calculation determination of the main parameters of smoke ventilation of buildings” dated 2008.

Regulatory documents determine the capabilities of the smoke removal system:

• maximum number of people in the room;
• area of ​​the building served.

The company carrying out the development and installation of a smoke removal system must have a License from the Ministry of Emergency Situations of Russia to carry out activities for the installation, maintenance and repair of fire safety equipment

Nuances of smoke removal design

When developing a project and installing a smoke removal system, experts recommend taking into account a number of fundamentally important points:

• integrity of smoke-permeable structures;
• placement of fire-resistant partitions in the overall ventilation scheme;
• the ability to test the smoke removal system with “cold smoke”;
• where air ducts pass through enclosing structures, it is necessary to install fireproof valves;
• in certain regions, seismic loads must be taken into account.

The layout of air ducts is significantly influenced by the location of fire-resistant partitions. Changes in the location of such a partition may entail rearrangement of the air distribution. This is especially true if a separate air supply unit is used in each room.

Cost of fire ventilation

Development of a smoke removal project and installation of the system will cost approximately 2,000 rubles/m2. The price will depend on the complexity of the project and the equipment used.

The smoke removal system costs 2-3 times more than a conventional ventilation system

The cost is calculated based on the following components:

Installation and adjustment of a smoke removal system

The initial stage of installation is laying welded air ducts in the room according to the developed plan. After this, the installation of fans begins. Axial, radial or roof fans can be used.

An important stage in the installation of smoke removal is the treatment of shafts special coating, which protects the complex from fire. After the required level of fire resistance on the air ducts has been achieved, fire dampers are installed - they are placed in shafts running under the ceiling.

Fastening of air ducts and placement of valves is carried out in strict compliance with the requirements of the working documentation

The final stage is connecting the automation, setting up and testing the smoke removal system.

When setting up the system, it is imperative to check the operation of the valves in manual and automatic modes, calculate the actual air flow (preferably separately for each zone), and check the fan rotation speed.

During commissioning, it is necessary to give the fan a rest - at least one hour every 30 minutes

When checking the operation of booster fans, you need to pay attention to the following parameters:

• direction of rotation of the fan blades;
• operation of fire-retarding valves (manual and automatic control);
• fan pressure measurement;
• comparison of real pressure indicators with the specified aerodynamic characteristics of the fan.

By using measuring instrument Using a differential pressure gauge, it is necessary to determine the excess pressure in elevator shafts, staircases and airlock vestibules.

The pressure difference between the street and the room must be at least 20 Pa - this means that the fan pressure complies with the established standards and the smoke removal system is designed correctly

Fire ventilation maintenance

A schedule is developed for each smoke removal system. Maintenance. Instructions for scheduled maintenance are provided by the manufacturer and installer of the system.

Timely maintenance eliminates the possibility of fire ventilation failure at the most critical moment. During a system check, you can identify problems in a timely manner and eliminate them, and replace some elements of the complex with more modern equipment.

Maintenance is carried out monthly and quarterly. Once a month the following work is performed:

• checking the technical condition and operability of the alarm system;
• technical diagnostics of devices;
• checking fastenings and external assessment of the condition of valves and equipment;
• trouble-shooting.

The quarterly inspection includes the following activities:

The results of each inspection must be recorded in a journal in the prescribed form.

It's safe to say that a smoke extraction system is vital to keeping people safe during a fire. The development and configuration of the system are determined at the design stage, the equipment must be certified, and the management and maintenance of the complex must comply with the established standards of the Russian Federation.