Fire doors and gates. Interesting and necessary information about building materials and technologies Fire resistance limit loss of bearing capacity of the structure

Load bearing capacity

The maximum load that building structures, their elements, as well as foundation soils can carry without losing their functional qualities.

Fire resistance of reinforced concrete. Limit states for fire resistance for reinforced concrete structures. Factors influencing the value of the fire resistance limits of reinforced concrete structures. General principles for calculating the fire resistance limits of reinforced concrete structures and ways to increase their fire resistance limits. Fire resistance of reinforced concrete structures (RCS). Under fire conditions, the limit of fire resistance of reinforced concrete structures occurs, as a rule: 1) due to a decrease in the strength of concrete when it is heated 2) thermal expansion and thermal creep of reinforcement 3) the occurrence of through holes or cracks in the sections of the structure 4) as a result of the loss of heat-insulating ability The most sensitive to fire are bent reinforced concrete structures: slabs, beams, crossbars, girders. Their fire resistance limit is usually within R50-R90. Such a low value of the fire resistance limits of bending elements is explained by the fact that the working reinforcement of the stretched zone of these structures, which makes the main contribution to their bearing capacity, is protected from fire only by a thin protective layer of concrete. This determines the speed of heating of the working reinforcement of the structure to the critical temperature. The fire resistance of compressed reinforced concrete elements is exhausted in case of fire due to a decrease in strength, the surface, most heated layers of concrete and the resistance of the working reinforcement during heating. This leads to a rapid decrease in the bearing capacity of the structure in case of fire. At the moment of fire exposure, when the bearing capacity of the structure decreases to the level of working loads, and its fire resistance limit on the basis of "R" comes. For reinforced concrete columns, the fire resistance limit is usually in the range of R90-R150. Limit states for fire resistance for reinforced concrete structures. Factors influencing the value of the fire resistance limits of reinforced concrete structures. The fire resistance limit states for reinforced concrete structures are: 1) loss of strength (R) 2) loss of heat-insulating ability (I) 3) loss of integrity (E) In contrast to metal structures, for which the fundamental value in assessing the fire resistance limit by loss of strength (R) is the reduced thickness (tred) of the cross section, in order to assess the fire resistance of a reinforced concrete structure on the basis of loss of strength (R), it is necessary to know: 1) type of concrete 2) min. distance from the heated surface to the axis of the working reinforcement 3) dimensions of the structure section 4) support scheme. To assess the fire resistance of a reinforced concrete structure on the basis of the loss of heat-insulating ability (I), it is necessary to know: 1) the type of concrete 2) the thickness of the structure (for a structure with internal voids - the effective thickness of the structure). The calculation of the fire resistance of any building structures on the basis of loss of integrity (E) is very complex technical challenge and is usually not done. The fire resistance of reinforced concrete structures depends on many factors: structural design, geometry, level of operational loads, thickness of concrete protective layers, type of reinforcement, type of concrete, and its moisture content, etc. General principles for calculating the fire resistance limits of reinforced concrete structures Calculations of the fire resistance limits of reinforced concrete structures, as well as for metal structures are associated with the solution of strength (static) and heat engineering problems. Unlike a metal structure, which consists of only one material - metal, the fire resistance limit of reinforced concrete is lost as a result of the loss of strength properties, both of the supporting metal reinforcement and of the concrete itself. The loss of the strength properties of metal reinforcement occurs as a result of heating it to a critical temperature (), which, in turn, depends on the stresses in the section of the metal reinforcement (from the applied load), the type of reinforced concrete structures, the scheme of support and loading of the reinforced concrete structures, the brand of reinforcement metal. The loss of the strength properties of concrete also occurs as a result of heating it to a critical temperature (), at which it is believed that concrete instantly loses its strength properties.

19. The fire resistance limit of structures and their limit states for fire resistance in accordance with Federal Law No. 123-F3. Fire resistance limit of the structure(filling the openings of fire barriers) - the time interval from the beginning of fire exposure under standard test conditions to the onset of one of the limit states normalized for a given design (filling the openings of fire barriers).

Article 35 123-FZ: The fire resistance limits of building structures are determined under standard test conditions. The onset of the fire resistance limits of load-bearing and enclosing building structures under standard test conditions or as a result of calculations is established by the time one or several of the following signs of limit states are reached:

1) loss of bearing capacity (R);

2) loss of integrity (E);

3) loss of thermal insulation due to an increase in temperature on the unheated surface of the structure to the limit values (I) or the achievement of the limit value of the heat flux density at a normalized distance from the unheated surface of the structure (W).

3. The limit of fire resistance for filling openings in fire barriers occurs when the integrity (E), heat-insulating ability (I), the limiting value of the heat flux density (W) and (or) smoke and gas impermeability (S) is reached.

4. Methods for determining the limits of fire resistance of building structures and signs of limit states are established by regulatory documents on fire safety.

5. Symbols of the fire resistance limits of building structures contain letter designations of the limit state and group.

Building structures of buildings, structures and structures, depending on their ability to resist the effects of fire and the spread of its hazardous factors under standard test conditions, are divided into building structures with the following fire resistance limits:

1) non-standardized;

2) at least 15 minutes;

3) at least 30 minutes;

4) at least 45 minutes;

5) at least 60 minutes;

6) at least 90 minutes;

7) at least 120 minutes;

8) at least 150 minutes;

9) at least 180 minutes;

10) at least 240 minutes;

11) at least 360 minutes.

Fire resistance is one of the main performance indicators of a structure that characterizes the ability of load-bearing elements, walls and floors of a building to resist the effects of fire and high temperature during a fire. This indicator is mandatory when designing a structure.

Based on the determination of the degree of fire resistance of buildings and structures of various engineering communications: electrical wiring, gas and water supply. This indicator is fundamental for determining the power, type and structure of various systems fire safety:

Alarms;
installations and standalone modules fire extinguishing;
Evacuation and emergency lighting;
Smoke removal.

In accordance with the current ones, 8 main degrees of fire resistance are distinguished.

The property of a material of a structure combined from several materials to resist an open flame and high temperatures without losing its basic load-bearing capabilities and functional characteristics is called the fire resistance limit. It is expressed in the digital equivalent of time with an alphabetic cipher:

R is the loss of the bearing capacity of the building structure;
E - loss of structural integrity;
I - loss of heat-insulating ability of the material.

For example, a fire resistance limit of ei 30 means that it will maintain its integrity and protect against high temperatures for 30 minutes.

Table 1: Fire resistance limit of building structures

Table 2: Fire resistance limit of fire barriers, special building structures used for fire containment

Table 3: Fire resistance limit of structures filling openings (windows, doors, gates) in fire barriers

Ways to increase the fire resistance of building materials

There are a number of ways to increase the time of resistance of structures and materials to fire:

Coatings and plasters. One of the most common and available ways. It can be used for materials such as wood and chipboard products, reinforced concrete, concrete blocks, metal, polymer building materials. It can be used both on load-bearing and enclosing structures. The effective thickness of the protection layer is not less than 25mm. Good protection indicators are demonstrated by such coatings as: lime-cement plaster, vermiculite, perlite. The use of asbestos-vermiculite is more common, but only allowed in rooms with limited traffic due to the harmful effects of asbestos.

Facing. It can be carried out as special materials like gypsum boards or fireclay bricks, and ordinary ceramic bricks. The effectiveness of the protection depends on the thickness of the insulation. A clay slab up to 80 mm thick increases the fire resistance of a concrete column to 4.8 hours. And facing the same element with ordinary clay bricks - only up to 2 hours.

Protective screens. Most often, such structures in the form suspended ceilings with fireproof slabs, floor panels are closed. Modern manufacturers finishing materials produce a fairly large number of flame-retardant sheet cladding and siding, which can be installed on walls and columns. Screens can differ in their protective effect: heat-removing and absorbing. The latter, as a rule, protect against the radiant energy of an open flame. The design also differs, there are stationary screens and mobile (temporary).

One of the types of protective screens are water curtains. They are created various installations automatic fire extinguishing, usually drencher. They can be classified as a separate method of increasing fire resistance. However, with the rapid spread of the source of fire over a large area, this method is ineffective. Recently, there have been solutions to more effectively protect . Bearing columns are cooled by water circulation in the internal cavities of the product.

Chemical protection. Typically, flame retardant compounds in the form of impregnations are used for wood processing. However, this method is quite expensive and laborious. In addition, its effectiveness largely depends on the type of wood - the structure and density of wood fibers. In most cases, the acquired protective properties of the material are significantly lower than those advertised by the flame retardant primer manufacturer.

Protective paints and varnishes . They are applied to the surface of the building structure and are suitable for use on any building material. The principle of operation of most of these protections is the thermosetting effect. Under the influence of temperature, the paint swells, creating an additional layer of thermal insulation. Such coatings have a relatively affordable cost, are simple in the preliminary preparation of the base and the mixture itself. Easy to apply on surfaces of any complexity. They have good flame retardant performance and a wide range of applications. As a rule, they are used to increase the fire resistance of metal structures.

The most common at the moment are the following tools:

Germany - Piromors, Uniterm;
Finland - Winter;
Hungary - Flams SAFE;
Russia - Firex;
Ukraine - OVK - 2, Endotherm - XT - 150.

In spite of highest efficiency, such materials can be prepared independently. To do this, it is necessary to mix asbestos crushed into powder and liquid glass in proportions of 4 to 10, respectively. Mix the mixture thoroughly. Depending on the consistency, it can be applied with a brush, roller or spray gun. Approximate consumption of the protective mixture is 0.5-1 kg / m 2 with a layer of 2-3 mm.

When using multi-component protective chemicals it must be remembered that some of them contain organic components. When the temperature exceeds 300 ° C, such products decompose with the release of toxic substances into the atmosphere. It is preferable to use mineral-based intumescent coatings with liquid glass in the form of a binder VZP-1 - VZP-12.

Wood pressing. A relatively new and expensive method, which consists in introducing special chemical substances softening cellulose. After that, pressing is carried out under high pressure. After that, the material acquires a significant density and strength, as well as resistance to fire with an increase in the category to slow-burning.

Features of determining the fire resistance limit of building structures

Before determining the fire resistance of a structure, it is necessary to calculate the fire resistance of the building structures that make it up. In such a calculation, certain nuances must be taken into account.

Firstly, layered fences are significantly superior in their thermal insulation characteristics each individual material from which they are made.
Secondly, products containing air layers in their composition increase their level of fire resistance by an average of 10% compared to similar products that do not have such a layer.

Thirdly, when calculating, it is necessary to take into account the direction of the heat flow and appropriately place the protective layers, up to their asymmetrical deposition.

In the system of measures to ensure fire protection of buildings and structures for various purposes important place occupies the use of fire barriers. Common fire barriers include walls, partitions, ceilings. To local - doors, gates, hatches, valves, latches, etc. Buildings should provide for structural, space-planning and engineering solutions that provide in case of fire:

the possibility of evacuating people, regardless of their age and physical condition, outside to the territory adjacent to the building (hereinafter - outside) before the onset of a threat to their life and health due to exposure to fire hazards;
the possibility of saving people;
the possibility of access for the personnel of fire departments and the supply of fire extinguishing means to the source of the fire, as well as carrying out measures to save people and property;
non-spread of fire to adjacent buildings, including the collapse of a burning building;
limiting direct and indirect material damage, including the contents of the building and the building itself, with an economically justified ratio of the amount of damage and the cost of fire fighting measures, fire protection and its technical equipment.

One of the parts of the building that provides the possibility of evacuation, limiting the spread of fire, etc. is the door.
Fire door structures are characterized by the maximum fire resistance, in other words, the ability to trap the flame and protect people from the harmful effects of combustion products.

Fire doors are part of the fire barriers in a building and provide reliable protection premises from fire, preservation of material assets and protection of buildings from the spread of fire, smoke and toxic substances that are formed during combustion. The main purpose of fire doors is to facilitate the evacuation of people, the fire is localized in places of ignition and does not spread to neighboring rooms.

The main regulatory document regulating the use of fire doors is Federal Law No. 123 " Technical regulation on fire safety requirements.

Fire doors are manufactured in accordance with existing technical requirements.

The design of the fire door must meet the requirements of fire resistance and fire hazard. And the materials used for the production of fire doors are selected according to the characteristics of their resistance to fire (fire hazard).

Building materials are divided into nonflammable and combustible, subdivided into four groups G1 (low combustible), G2 (moderately combustible), G3 (normally combustible), G4 (highly combustible). The characteristics of combustible materials are flammability, flammability, flame spread over the surface, smoke generating ability, toxicity. Doors, gates, hatches and valves are allowed to be made using materials of combustibility groups not lower than G3, protected by non-combustible materials with a thickness of at least 4 mm.

Doors of tambour locks, doors, gates and hatches in fire barriers from the side of rooms in which combustible gases, liquids and materials are not used and stored, and there are no processes associated with the formation of combustible dust, it is allowed to be made of materials of combustibility group G3 with a thickness not less than 40 mm and without voids. Those. the production of fire-retardant interior doors is carried out using non-combustible materials (asbestos cardboard, mineral wool asbestos-perlite-vermiculite-containing compositions). On both sides this interior door sheathed with roofing iron.

By fire hazard building structures are divided into four classes: K0 (not fire hazardous), K1 (slightly fire hazardous), K2 (moderately fire hazardous), K3 (fire hazardous). The fire hazard class of building structures is established in accordance with GOST 30403. The fire resistance indicator is the fire resistance limit, the fire hazard of a structure is characterized by its fire hazard class.

Limiting state of the structure for fire resistance the state of a structure in which it loses the ability to maintain one of its fire-fighting functions. The fire resistance limit of building structures is established by the time (in minutes) of the onset of one or several successively, normalized for a given structure, signs of limit states:

bearing capacity loss (R);
loss of integrity (E);
loss of heat-insulating ability (I).

Loss of bearing capacity- this is the collapse of the structure or the occurrence of limiting deformations.

Loss of integrity- this is the formation in structures of through cracks or holes through which combustion products or flames penetrate onto an unheated surface.

Loss of thermal insulation ability- this is when the temperature on the unheated surface of the structure rises to the limit values \u200b\u200bfor this structure.

The designation of the fire resistance limit of a building structure consists of symbols, normalized for a given design of limit states R, and a figure corresponding to the time to reach one of these states (the first in time) in minutes. For example:

R 120 fire resistance limit 120 minutes for loss of bearing capacity;
RE 60 fire resistance limit of 60 minutes in terms of loss of bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 30 minutes fire resistance limit for loss of bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs first.

Fire barriers, depending on the fire resistance of their enclosing part, are divided into types:

Type 1 fire barriers must be class K0. It is allowed in specially stipulated cases to use fire barriers of the 2nd-4th types of class K1.
According to SNiP 21-01-97 * fire doors, as filling openings in fire barriers, must have the following fire resistance limits:

Tambour locks provided in the openings of fire barriers, depending on the fire resistance of their enclosing part, are divided into types:

Doors intended for the evacuation of people in emergency situations, as well as the leaves of airlocks and other automatic doors, must swing open in the direction of people's movement without hindrance.

The door opening direction is not standardized for:

premises of classes F1.3 (multi-apartment residential buildings) and F1.4 (single-apartment, including blocked residential buildings);
premises with a simultaneous stay of no more than 15 people, except for premises of categories A and B;
pantries with an area of not more than 200 sq.m without permanent jobs;
sanitary facilities;
access to the platforms of stairs of the 3rd type (external open);
exterior doors of buildings located in the northern building climate zone.

Doors of emergency exits from floor corridors, halls, foyers, vestibules and stairwells should not have locks that prevent them from being freely opened from the inside without a key.

Stairwell doors leading to common corridors, elevator hall doors and doors of airlocks with constant air overpressure must have devices for self-closing and sealing in the porches, and airlock doors with air overpressure in case of fire and doors of rooms with forced smoke protection must have automatic devices for their closing in case of fire and sealing in the porches. In case of fire, openings in fire barriers should, as a rule, be closed. Those. doors must be equipped with devices that ensure their automatic closing (drives, closers, a mechanism for adjusting the closing order, keys, buttons). At the same time, if such doors are located on people's evacuation routes, they must be provided with the "Anti-panic" mode, i.e. they must be fitted with door locks and handles allowing a locked door to be opened without a key from one side (usually from the inside). It is also necessary to provide for the operability of the door in case of power failures.

To achieve the above parameters, constructive solutions of the box and door leaf are used. Used for regular steel doors the method of manufacturing boxes from steel pipes of square or rectangular section, forming a porch and a casing when connected, gives a fire resistance limit of 30 or 45 minutes. The use of steel profiles is more promising. Connection of profiles into a box simultaneously forms a casing and gives a fire resistance limit of 60 minutes. The door leaf is a box with heat-insulating material inside. Mineral wool boards are widely used. basalt rocks and drywall sheets. The door leaf can also be made of glass having a certain fire resistance limit.

Currently, fire doors not only perform their main function, but are also a decor item. Therefore, they can be trimmed various materials. The color scheme can be any. The special fittings installed on them satisfy aesthetic requirements. Doors can be both deaf and partially glazed. Their design can be single-leaf, double-leaf, sluice, etc.

The fire door must be subject to mandatory certification. The document confirming the certification of this door is a fire safety certificate issued by the relevant certification body based on the results of product testing by a testing laboratory accredited in the fire safety certification system.

Fire doors are tested on the basis of GOST R 53307-2009 Building structures. FIRE DOORS AND GATES. Test method for fire resistance.

Tests are carried out until one or successively all limit states occur.
When testing doors, the following limit states are distinguished:

1. Loss of integrity (E) or loss of the door leaf from the box or the box itself from the building envelope.

2. Loss of thermal insulation capacity (I) - due to an increase in temperature on the unheated surface of the door leaf by an average of more than 140 °C or at any point on this surface by 180 °C in comparison with the temperature of the structure before the test or reaching a temperature of 300 °C by door frame regardless of design temperature prior to testing.

This is how fire doors are actually tested (watch the video):

Further, such a fire door is reasonably supplied for sale. Although there are cases when unscrupulous Suppliers sold fire doors contrary to Article 238 of the Criminal Code of the Russian Federation: "Production, storage, transportation or sale of goods and products, performance of work or provision of services that do not meet safety requirements."

In addition to the manufacture and testing of fire doors, the Supplier (Contractor) is subject to the Decree of the Government of the Russian Federation dated December 30, 2011 N 1225 “On licensing activities for the installation, maintenance and repair of fire safety equipment for buildings and structures” (together with the “Regulation on licensing activities for installation, maintenance and repair of fire safety equipment for buildings and structures")

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WORKS AND SERVICES CONSTITUTING THE INSTALLATION ACTIVITIES,
MAINTENANCE AND REPAIR OF MAINTENANCE FACILITIES
FIRE SAFETY OF BUILDINGS AND STRUCTURES

8. Installation, maintenance and repair of filling openings in fire barriers;

From the foregoing, it certainly follows that when ordering fire doors, it is necessary to request relevant information from a potential Supplier (Contractor), namely:
- availability of certificates and passports for fire doors and foam (it must be fire resistant);
- availability of a license for the right to engage in the installation, maintenance and repair of fire doors.

Installation of fire doors is carried out in accordance with GOST 31173-2003 STEEL DOOR BLOCKS. Specifications. This standard regulates the following main points:

design features

Installation of fire-resistant door structures is carried out in military units, police departments, and in factories. fire door made of steel sheets it has layers of an insulating composite inside - mineral wool slabs, which is equipped with a pair of layers of a special sealant and foam inserts. Fire-resistant door structures made of aluminum sheet are made according to a similar principle. These doors can contain one or more canvases and swing open by a hinged or sliding mechanism.

Recently, fire-resistant door structures made entirely of special heat-resistant glass have been used. The requirements for such door structures are completely similar to the permitted parameters for the fire resistance of wooden and metal door structures.

According to the law on fire protection, fire-resistant door structures are mounted in a strict order in industrial buildings, in residential buildings, if there are social facilities on the ground floors, in warehouses, on escape routes, emergency exits. Considering the advantages of fireproof doors to ensure security, most order them for installation in cottages and apartments. Therefore, fire doors are manufactured in a variety of design solutions so that the doors can fit into any interior.

After the certified fire doors are installed by a licensed organization, Decree of the Government of the Russian Federation of April 25, 2012 N 390 "On the fire regime" comes into force.

61. The head of the organization ensures the good condition of the systems and means of fire protection of the facility ( automatic installations fire extinguishing and alarm systems, installations of smoke protection systems, a fire warning system for people, fire alarms, fire water supply systems, fire doors, fire and smoke valves, protective devices in fire barriers) and organizes at least 1 time per quarter a performance check of these systems and means of fire protection of the facility with the execution of the relevant inspection report.
When installing, repairing and maintaining fire safety equipment for buildings and structures, design solutions, requirements of regulatory documents on fire safety and (or) special technical conditions must be observed.
The facility must store executive documentation on installations and systems of fire protection of the facility.

That is, the Head of the organization (RBTD) organizes an inspection of fire doors at least once every 3 months with the execution of an appropriate inspection report.

Download the inspection report— Please or to access this content

Where fire doors need to be installed:

- in rooms where there is a possibility of ignition of equipment or materials.

It is allowed to install fire-resistant entrance doors in residential, office, social and industrial buildings. Be sure to install such doors in rooms where there are a lot of working electrical appliances and there is a danger of ignition of the wiring and ignition of the building.

- in industrial buildings all passages separating warehouses from workshops (offices) or utility rooms, rest rooms must be separated by fire doors;

- in residential buildings where there is an incorporation of non-residential premises. This is a very common situation, especially for large cities. If in the same entrance (especially on the same floor!) Both offices and residential apartments, then according to the requirements of the fire safety service, the office door facing the common staircase must be fireproof.

In accordance with building codes, the installation of fire doors is mandatory in such premises as:

pumping stations

ventilation chambers

Fire doors in residential and office multi-storey buildings should be equipped with:

floor platforms

Doors can be installed in stone, brick or reinforced concrete walls.

Fireproof door structures are fire resistant, i.e. fire resistant. In the event of a fire for a certain time, the door resists fire, while the temperature of the door leaf on the side of the fire does not heat up above 180 ° C.

The fire door must maintain fire resistance for the time specified in the certificate. According to GOST, this is 15, 30, 45, 60, 120, 150, 180, 240, 360 min. But in practice, the most fire-resistant doors can withstand no more than 2 hours.

A number of domestic firms use steel pipes of rectangular or square section for the manufacture of boxes, which form a porch and a platband when connected. However, this traditional method for ordinary steel doors constructive solution boxes, as a rule, limits the fire resistance of door structures to 30 or 45 minutes.

The most promising both in terms of performance and appearance is the use of steel profiles. In this case, taking into account the technological capabilities of the manufacturer, the box is a complex profile made of steel sheet, or assembled from several special profiles. In both cases, the box is a rigid structure and simultaneously forms a casing. It withstands tests for 60 minutes or more.

The fire door must be chosen in such a way that if a fire occurs in the room and it burns out completely, then the integrity of the door will not be violated. On average, a living room engulfed in flames burns out in 15-20 minutes. Offices can burn longer (due to equipment and synthetic finishes: walls, floors, ceilings, furniture). Hence the conclusion: the fire resistance of the door must necessarily be more than 30 minutes.

To prevent the metal (steel) fire door from deforming, it is impossible to allow significant heating of any part of it: the heated part expands and "leads" the entire structure. As a result, the door jams. By the way, during a fire accompanied by explosions of flammable materials, an almost instantaneous increase in temperature occurs. Therefore, in warehouses where petroleum products, solvents and compounds based on gasoline, kerosene, acetone, etc. are stored, it is better to install a door in which the metal is insulated with another material.

A worthy manufacturer develops a model in such a way as to minimize the likelihood of deformation. But if this happens, then the fire door leaf should not deform in the directions of the "parts of the world" (up / north, down / south, left / west, right / east), but only inward or outward. That is, it is allowed that the door leaf "swells with a bubble" or arches inward, but does not "open" in the door frame so that it is impossible to open.

To minimize the heating of the door from the side where there is no fire (to minimize heat transfer), the internal parts of the metal door structure connecting the front and back parts are supplemented with heat-insulating gaskets (heat insulators), or, as they are also called, heat bridges. The internal heat-insulating material of a fire door can be a mineral slab based on basalt fibers. Moreover, the longer the basalt thread, the slower the destruction of the slab will occur under the influence of temperature.

The main requirement for a fire door is ease of opening in emergency situations. Otherwise, the escape door can become a real trap for fear-stricken people. Therefore, especially great importance has a system that allows you to leave in an emergency dangerous territory. At the same time, the fire door must close very tightly to prevent the spread of smoke and long time resist fire. At the same time, the requirements for protective and strength properties that are standard for all door structures are also imposed on fire doors.

In most fire door systems, this problem is solved as follows. First of all, in order to comply with the requirements of fire safety regulations, all fire and escape doors must be equipped with special locks (latches) with a slanting crossbar and a lever handle. This lock allows you to open the door from the inside by simply pressing the handle. At the same time, such a door can only be opened from the outside with a key. The mechanism of such a lock is made only of metal, due to which it remains operational even when heated to high temperatures. Such a system of implementation door lock typical for modern entrance doors, but in the case of fire protection structures, it seems to be the most relevant, since in extreme situation there simply will not be time to search for the key, and the slightest delay can cost a life. Also, in office buildings, doors are often double-leaf, while the second rack is held not by a lock unlocked by a key, but by an ordinary vertical latch, which can be pushed aside without problems to open the door.

Fire doors with anti-panic

To facilitate the evacuation of personnel or residents in the event of a fire, a special Anti-Panic system is used in fire doors. It functions as follows. Suppose the door is locked and it can only be opened from the outside special key. From the inside, all locks, no matter how many there are, open with one touch of a special handle. Most often, such a handle is made in the form of a bar, which can be moved without problems with a simple press. Typically, such a handle-rod is located at a height of about 100-120 centimeters from the floor, so in most cases it is enough to press the door with your whole body for the system to work and the door to open. This is especially important in the case when a person is seized with fear and thinks only about how to quickly get out of a burning building.

A number of fire doors - primarily tambour-type doors - are automatically closed in case of fire to prevent the spread of fire, smoke and other combustion products to adjacent rooms. However, the use of the Anti-Panic system makes it as easy to open them as any others. Often, fire doors, in addition to the Anti-Panic system, are also equipped with an automatic lock and a door closer. After a person leaves the room, the door behind him is slammed with a closer and fixed with a lock to prevent the spread of fire. At the same time, the use of the lock is not a hindrance to the Anti-Panic system, which will open the door over and over again in front of each person running out of the room. Also quite often used is a self-powered electric drive, which, upon receiving a signal from fire alarm sensors, tightly closes the doors.

Electromagnetic
door holder

In cases where a closed fire door obstructs the passage a large number people (in office buildings, shops, etc.), it is necessary to install an electromagnetic door holder, which is designed to hold the door open in case of fires or other cases of emergency evacuation

This door can be closed manually by pressing the indicator button.

If during the daytime the fire door must be constantly open, and in the event of a fire must be automatically closed to prevent the spread of smoke and fire through the building, then in this case, automatic systems closing doors on a fire alarm signal or an autonomous fire detector.

Smoke sensors (1) react to the occurrence of smoke and form alarm signal in the fire door closing system (2). After that, the automatic electric closer closes the door and fixes it in the closed position (3). If such a device is not provided, then it can be expected that the door will be held open by a foreign object and its fire-fighting properties will remain unclaimed in an emergency.

Closing system
fire doors

Structurally, fire doors are manufactured in two main types - single and double doors.

Single-leaf fire doors consist of a single leaf fixed to a metal or wooden frame door frame. Single-leaf fire doors are easy to use, highly resistant to burglary and open wide opportunities for aestheticization of the door leaf with the help of functional glass inserts.

Single leaf metal fire door:

Two-leaf fire doors are made of two door leafs. The leaves of double-leaf doors have the same direction and type of opening. Among double-leaf doors, equal-field and unequal-field doors are distinguished, depending on the ratio of the width of the leaves. In general, the method of manufacture and design of double-leaf doors differs little from similar doors with one leaf, but the installation of double-leaf doors has a number of features.

Double leaf metal fire door:

1. Door leaf, 2. Door frame, 3. Hinge, 4. Lock, 5. Handle, 6. Mineral wool filler, 7. Thermal seal, 8. Mounting hole plug, 9. Anchor bolt, 10. Wall, 11. Otkos, 12. Fireproof glass.

Depending on the materials used, wooden, glass and metal fire doors are distinguished. Wooden fireproof doors have a frame made of coniferous materials impregnated with flame retardants, or steel. Unlike ordinary doors, fire doors are more powerful. From the outside, the door is covered with veneer, heat-resistant plastic and other materials. Inside the door is mineral wool, basalt fiber and other refractory materials. Thermal expansion and rubber fire seals are installed along the perimeter of the door to protect against smoke. Wooden fire doors have a low degree of fire resistance and can hold a fire from fifteen minutes to an hour. Usually this time is enough for the fire brigade to arrive and start extinguishing the fire.

Glass fire doors consist of a steel frame and single or laminated fire resistant glass that has the same fire rating as the fire door.

Previously, glazing was used only in the form of small viewing holes, while modern technologies make it possible to produce large-sized frames with human-sized glass. Special heat-resistant and impact-resistant glass is installed in a narrow profile frame, which ensures that the structure fully complies with fire safety requirements.

Glass and glazed fire doors reliably prevent the spread of fire and smoke, provide enclosing functions and reliably isolate high temperatures for a long time. Thanks to these qualities, glass fire doors allow for the timely evacuation of a large number of people and protect combustible materials located behind the door on the opposite side from the source of ignition from fire.

Glass fire doors are produced on the basis of a modern high-temperature profile filled with a special non-combustible insulator - mineral wool. The frame of the door leaf is made from the profile, into which a special heat-resistant glass is inserted.

Modern heat-resistant glasses are produced according to multilayer technology. between panes special composition layers of a transparent gel-like solution of mineral salts are located. As the temperature rises, water evaporates, which contributes to additional cooling of the frame, and mineral salts begin to rapidly crystallize, forming a porous layer with extremely low thermal conductivity characteristics. In case of fire, such fire-resistant glass does not heat up completely. First, the outer sheet of glass is heated, the gel at this time becomes cloudy, expands and protects the next sheet. The resulting cracks are also filled with fire-fighting gel. The next sheet of glass is exposed to heat only after the complete destruction of the previous one. Thus, by breaking down layer by layer, fireproof glass withstands the impact of a fire for the stated time. In addition to fire protection, such glasses have high impact resistance.

Heat-resistant glasses with gel filler are produced different thickness and with different number of layers.

The glass fire door leaf assembly is fixed on the door frame, also made of heat-resistant profiles. To facilitate the opening of the door in an emergency, it is equipped with a special lock with an oblique metal bolt, which does not jam at high temperatures. To ensure reliable isolation of the source of fire from other rooms, a door closer is used.

The use of fire doors with heat-resistant glazing should be without fail be certified by the relevant government agencies. During certification, each element of the structure is tested - the frame, cover, load-bearing elements, glass attachment points, as well as the quality of the smoke seal.

When fulfilling an order for the production of fire-resistant glazing, the manufacturer is obliged to issue a certificate confirming the compliance of the materials used with existing building codes and fire safety rules.

Metal fire doors are made from steel or aluminum sheets welded using a special technology. Inside the door leaf is filled with refractory materials, mineral wool, gypsum-fiber sheets or synthetic substances with low thermal conductivity are used. The door frame around the perimeter is glued with heat-resistant tape and seals. From the outside metal doors covered with anti-corrosion compounds and powder paint a variety of colors.

It is metal fire doors that have a high fire resistance coefficient. Sturdy steel fire doors are made from two sheets of alloy steel that are bent in a special way. Thick steel doors are made if increased burglary resistance or bullet resistance is needed. And steel fire doors are made from thin-sheet cold-rolled steel using a bent-welded method. Thin steel is necessary so that the structure accumulates and transmits as little heat as possible and has a high fire resistance.

Workpieces bent in a special way (outer and inner sheets), as well as a one-piece bent door frame, allow you to get a strong, durable construction. And the low weight of the leaf, obtained due to the thin steel sheets used, prevents sagging and deformation of the door.

foreign doors high class burglary resistance and equipped with powerful protective devices have a very small mass - the lightness of the design is achieved through the use of alloy steel with anti-corrosion coating. Excessive mass of the door, in addition to inconvenience in operation, leads to rapid wear of the hinges and facilitates breaking, as the load on the wall of the doorway increases and the door warps.

Box types may vary. Fire doors can be single or double leaf, blind or glass, with right or left door opening. double door compared to a single-leaf, it is more vulnerable in a fire.

For office and industrial premises, it is better to use special fire-resistant doors for technical premises. When installing fire doors, fireproof locking mechanisms and handles are used. Ordinary locks often jam when a fire occurs, and a person cannot leave the room. Anti-panic systems are usually installed in fire doors, the doors open from the inside with a handle.

For a cottage or apartment, it is preferable to choose wooden or steel fire doors, their fire resistance limit is 30 minutes. For office buildings, where there is a lot of equipment, they are used for decoration synthetic materials, can burn longer, so the degree of fire resistance should be higher.

Wooden doors are made from solid wood with door frames, strong frames and special seals that prevent the spread of fire and combustion products. Under the influence of high temperatures, the composite foams and seals the cracks, which ensures complete insulation. Fire-resistant doors made of wood prevent an increase in the source of ignition. Wooden door structures are installed in preschool institutions so that the children are not injured on heavy metal doors, and half an hour of fire resistance makes it possible to evacuate all the children in a timely manner.

When choosing fire doors, you should consider the presence of smoke protection, since when a fire occurs, people often die from toxic substances.

Smoke and gas tight door structure:
1 - shield
2 - loop on the bearing
3 - fire-fighting penta

4 - rubber seal

To do this, a special thermally expanding strip is placed along the edge of such a door in the groove (around the entire perimeter) - a foaming anti-smoke insert from hot smoke, rubber - from cold smoke, which is not noticeable if the door is closed. The tape is designed to prevent the release of combustion products and flames, which determines the fire resistance limit for loss of integrity (E). The most effective solution is to install the tape in a groove or under a thin decorative strip. A rather unsuccessful option is to stick the tape on the surface of the end part of the door leaf - in this case, during operation, it may be damaged or peeled off. During a fire, the insert foams, sealing the gaps, and protects against the penetration of combustion products into other rooms. Unfortunately, not every company explains what the filling of the door consists of, referring to its know-how. But whatever the door may be, its fire-fighting qualities must be recorded in the certificates.
Quite often, a fire door is also soundproof. In it, the internal filler simultaneously has two properties - heat-insulating and sound-absorbing.
Metal fire doors should be equipped with automatic closers and not interfere with the passage to neighboring rooms.

When ordering a fire door, it is imperative to pay attention to the presence of mandatory documents, the main of which are a fire safety certificate and a quality conformity certificate.
When buying a fire door directly from the manufacturer, you must request a license for the production of fire protection equipment issued by the relevant government authority. When buying from official dealer the buyer must be provided with certification test reports. You should also pay attention to the marking of doors: according to the current legislation, all fire-technical products must be marked, have the manufacturer's mark. On fire doors, such marks are engraved on special metal labels. The name and labeling of products often contains information about the declared characteristics of fire resistance. For example, EI 30 means that the door has a fire resistance rating of at least 30 minutes. by loss of integrity (E) and heat-insulating ability (I).

The fire resistance marking, which is applied to door structures, is read as follows:

Taking into account the ability to resist the flame, the doors are divided into two groups: wooden, enduring the action of the flame for half an hour and marked EI-30, and metal, which are able to withstand the flame from an hour to two. The fire resistance threshold should provide a period of time that allows organizing the removal of people from a fire hazardous facility. Identical markings are applied to glass heat-resistant elements, which can occupy a fifth of the surface area of the door.

A fire safety certificate for fire doors, gates or hatches is issued by the relevant state certification body for each of the product models only in case of strict compliance with the characteristics stated in the accompanying documentation and based on documented product test results by a specialized laboratory that has the appropriate accreditation in the fire safety system. The fire safety certificate must indicate the overall dimensions of the doors (height, width, thickness). In accordance with GOST, the test results are valid for all doors of this type with deviations in their overall dimensions in height and width from +10 to -30%, rounded up (up to 50 mm) and down (up to 100 mm) from the calculated values . In this case, the thickness of the door should be the same.
In addition, each enterprise that has a certificate for the manufacture of fire-fighting equipment is regularly inspected government bodies fire supervision and VNIIPO specialists. The purpose of the inspection is to check the current compliance of the characteristics of the products with the characteristics declared during certification. The penalty for deviation from the documented norms may be the revocation of the license. Knowing the certificate number, you can use the registry to determine who issued this document, and, if necessary, check its authenticity.

When choosing fire-resistant doors, it is necessary to pay attention to how many years the manufacturer of these products has been operating on the market, whether he is well-known, and whether his products have been criticized. Products manufactured by almost all well-known foreign enterprises are certified according to the ISO 9001, 9002 quality system.
Many manufacturers do not indicate the warranty period in the technical documentation or give a short period (1 year), thereby relieving themselves of responsibility for the long-term operation of products. Longer warranty periods produced by manufacturers who are confident in the quality of their products.

In market conditions, the price of products is determined primarily by their quality, design and demand for them.
The price of a fire door increases mainly due to the use of outdated technology and old equipment. Basically, these are the doors of small manufacturers who do not have enough funds for modern CNC machines. At large factories, the production of fire doors is arranged according to the flow principle, which greatly reduces the total time for the manufacture of one door and, consequently, its cost. Also, many manufacturers of fire doors use coordinate punching presses, which makes it possible to make the necessary technological holes already in the blanks. That is, there is no need for locksmiths to work - drilling holes for fastening accessories, cutting holes for a lock, etc. The use of thin sheet metal and a small amount of basalt wool greatly saves production costs.
Thus, the pricing of fire doors to a greater extent depends on the production technology. It should also be noted that the price of domestic fire doors is much lower than similar imported products.

Installation of fire doors

In general, the installation of a fire door consists of a number of operations that are somewhat different from the installation front door conventional design.

Required tools:

tape measure (3 meters);
level;
a hammer;
drill or perforator;
drill with a winning tip;
end key;
wooden wedges.

Expendable materials:

anchor bolts;
assembly fire-fighting foam;

· masking tape.

1. Taking measurements

If fire doors are made to order, it is necessary to call a measuring specialist who will take measurements from the opening (height, width, depth) and calculate the possible thickness and width of the door frame trim.

2. Preparation for installation

Doors (gates, hatches) that are not damaged during transportation and storage and are fully assembled are allowed for installation. Installation is carried out by an organization that has the appropriate license.
Doors (gates, hatches) fireproof metal are installed in openings that meet the following requirements:
- Non-flatness and non-verticality of the wall in the opening zone is not more than 5 mm.
- Non-horizontal floor in the area of the opening - no more than 5 mm.
— The difference between the diagonals of the opening should not exceed 10 mm.
In case of making an opening from a weak load-bearing structures and materials, it is necessary to strengthen the opening around the perimeter.
After mounting the fire door (gate, hatch), the cavity between the opening and the frame of the door (gate, hatch) must be filled with a cement-sand mixture or mineral wool board. Leaving gaps between the opening and the frame is not allowed.

Before mounting the box, the door leaf is removed, transferred and carefully placed on a flat surface or placed horizontally on the edge.

3. Door installation

A box is inserted into the opening and fixed in level with wooden wedges, providing uniform side gaps, installing them between the wall and the frame on the inside of the door. The gaps between the opening and the frame should not exceed 10 mm. Having inserted the box into the opening, through the holes in it, mark the places for drilling holes for anchor bolts.

Important! before fixing the doors and after it, it is necessary to align the position of the frame in the opening using a level. The diagonals must also be aligned.

Through the places provided on the frame, holes for anchor bolts are drilled in the wall with a puncher or an electric drill. The minimum number of anchor bolts is at least 2 per side. It is allowed to change the requirements for the number of anchors when changing the diameter of the pin and the depth of its embedding.

After removing the old doors, the opening is cleaned of plaster and putty (the size of the opening should be 20 mm larger than the size of the box, the maximum tolerance is +25 mm on each side). If the opening is within the horizontal and vertical tolerances, the installation is done immediately. If there are deviations, then it is necessary to refine the opening. To do this, level experts make the necessary marks and remove an extra section of the wall with a perforator.

Important! you need to drill carefully, because. live wires can be located in the wall (especially in concrete openings).

Inserting anchor bolts into the prepared holes, socket wrench tighten the nuts without finally tightening them. Then the door leaf is hung and adjusted (if necessary) and the nuts are tightened until the anchors are completely fixed in the wall.

Important! make sure that when tightening the anchors, do not stretch the door frame.

After the installation of the door, the wooden wedges are removed and the plugs are inserted into the holes of the box, in which there are expansion anchor bolts.

After that, the quality of the installation is checked (repeatedly open and close the doors). The door leaf should open/close smoothly, without jerking or jamming.

4. Thermal insulation

Then the specialists seal with mineral wool and fill the gap between door frame and masonry. It is allowed to use other building materials with similar properties.

To prevent foam from getting into the reciprocal parts of the locks, it is recommended to cover them with masking tape. After final drying polyurethane foam remove the masking tape, and carefully trim the excess foam flush with the door frame.

Important! when installing a fire door, in no case should you use ordinary flammable mounting foam!

5. Finishing

Mounting clearances around the perimeter door block they are covered with platbands treated with fire-retardant finishing materials according to the type and color of the door leaf finish.

Important! Docking of platbands along the length is not allowed.

The fire door is installed and ready for operation.

The installation of a door (gate, hatch) must be formalized by a bilateral act.

Fire door maintenance

Caring for a fire door does not fundamentally differ from caring for ordinary doors.

Believe me: if they are observed, the service life of your doors will increase significantly. Despite their strength and fire resistance, these doors can still be damaged. No matter how, however, they, and in particular some of their details, must be protected. The most frequently damaged parts are, for example, thermal insulation tapes. This is a very important part of the structure, the integrity of which determines whether smoke or toxic substances released during the fire enter another room during a fire.

Fire doors, like any other things, require compliance with the rules of operation.

The full period of operation of the door must correspond to the established service life from the moment of its installation until its decommissioning. The hinges must be lubricated in a timely manner, the surface must be cleaned from dirt, etc. The service life of the door should not exceed the maximum period set by the manufacturer and confirmed by the certification center. After this period, the door must be decommissioned and dismantled. Doors that have performed their direct function during a fire, or doors that have received mechanical damage, resulting in a strong deformation of the structure and a partial loss of insulating properties, are dismantled ahead of schedule.
In this case, the door must be dismantled and replaced.

Fire gate

One of the most effective methods passive fire fighting is to create barriers to the spread of fire. Such barriers can be made in the form of fire gates or curtains that protect building openings. Fire gates are designed, performing their normal operational functions, in the event of a possible fire, to block the spread of fire through the openings of buildings, creating conditions for localizing the fire, as well as the safe evacuation of people and protecting the ways along which the fire is extinguished in the building.

Which gate will be installed on a particular object is determined, first of all, by the features of this object. There are swing, retractable, sliding, lowering, sectional fire gates, fire curtains.

Sliding, sliding and lowering fire gates can be made in a telescopic design and contain 2-3 leaves. Telescopic gates are used when there is not enough distance necessary to place the gate plane above the edge of the opening to the wall or on the sides.

Sectional fire-resistant doors are convenient to use in cases where there is little space at the top and on the sides of the opening.

The feature of the group swing gates» is that they are often very large, for example, 4.000 x 4.000 mm, and then, in terms of their dimensions and method of opening, they are less practical than other types of gates.

Fire doors can be designed with a fire door built into them as escape doors. It is important that these doors do not have a threshold.
The most significant characteristic of fire-resistant building structures, the first criterion by which the customer selects one or another fire-resistant gate, is their ability to resist high temperatures in a fire, i.e. fire resistance. Fire resistance is indicated in time (minutes), after which a particular structure will lose its required properties. This parameter is regulated for a particular object building codes and rules (SNiP). The limit of fire resistance but the loss of integrity (H) and heat-insulating ability (I) is the time during which the structure will prevent the spread of fire. The minimum fire resistance limit of fire gates can be 15 minutes (HI 15), i.e. for 15 minutes, the gate protects against the spread of fire. Regarding Steel Fire Gates various types, then the most effective solutions in terms of fire resistance of the structure are doors with mineral wool filler. Their fire resistance limit depends on the density and thickness of the heat-insulating layer. The maximum fire resistance rating of fire doors and gates offered and certified for Russian market, often reaches 60 minutes (EI 60), there are also doors with a fire resistance limit of 90 minutes (HI 90). The high fire resistance of fire doors has an impact on the best building insurance conditions.

Other things being equal, fire resistance characteristics important role when choosing fire doors, their overall dimensions can play a role. Some fire-resistant gates on the Russian market are already certified with specific dimensions, other gate manufacturers declare in the certificate not specific measurements, but a possible range of dimensions. At the same time, there are buildings that require individual approach to the dimensions of the gate: for example, extensive factory premises or huge shopping centers, or, conversely, small compartments built into walls, hatches, as well as openings custom sizes. In this case, fire-resistant gates are made to order, taking into account the features of the object.

Manufacturing of fire gates individual sizes gives the object new opportunities in the protection of building structures, both under construction and reconstructed, which consist in reducing the level of fire hazard and, accordingly, increasing the level of protection of the premises. This effect is achieved by dividing the room into compartments with fire-resistant barrier gates. In the event of a fire in one of the compartments of the premises, fire gates localize the fire and prevent it from spreading to other parts of the premises. This can also reduce the cost of providing the facility with fire safety equipment, for example, reduce the amount of fire extinguishing agent in automatic fire extinguishing equipment.

The modern lifestyle often involves automation of the gate. Moreover, it may be important for the gate special purpose- fire-fighting, designed to create a barrier in the event of a possible spread of fire. Whether the gate will be closed manually or equipped with an automatic closing system depends on the characteristics of the facility and the customer's capabilities. Fire gates can be closed at the command of fire alarm sensors if significant additional funds are spent on equipping them with an electric drive.

Another example is the gate-obstacles of transport openings. In most factories, for fire safety, the workshops are divided into smaller spaces by fire separation walls. In such walls there are openings for transport systems. In the event of a fire, these openings must be closed in such a way that the closed gates do not linger on the transported material. To do this, the gates are respectively associated with vehicles and only close when space is free.

Gates are an important element of the interior of the room, sometimes calling card building. modern fire doors appearance are no different from ordinary gates: they have a beautiful design and are harmoniously combined with the rest of the structure in terms of color and structure. For example, such a structural element as a box in the inter-ceiling space allows you to make sectional doors inconspicuous when open. If the gate is installed in an open area, they are built up with very aesthetic decorative elements.

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Design, testing and assessment of fire resistance of fire doors. Recommendations VNIIPO - Please or to access this content

Fire doors that you can order from us:

Glass fire doors:

Fire resistant doors can be sold in ready-made or be made to order
under individual requirements fire resistance, number of leaves, dimensions, threshold height,
the number of layers of mineral filler, color scheme, box type.

Fire resistance design- the ability to maintain their bearing and (or) enclosing functions in a fire (clause 3.1 of SP 2).

The quantitative characteristic of the fire resistance of structures is fire resistance limit- the time from the start of the fire test under standard temperature conditions to the onset of one of the fire resistance limit states standardized for this design (clause 5.2.1 SP 2).

The main types of limit states of building structures in terms of fire resistance are (part 2 of article 35 123-FZ, clause 9 of GOST 30247.0):

· loss of bearing capacity due to the collapse of the structure or the occurrence of unacceptable deformations (R);

· loss of integrity as a result of the formation of through cracks or holes in the structures, through which combustion products or flames penetrate the unheated surface (E);

· loss of thermal insulation due to an increase in temperature on the unheated surface of the structure to the limit values for this structure (I).

The designation of the fire resistance limits of structures in accordance with clause 10 of GOST 30247.0 consists of symbols of the limit states normalized for a given structure and a figure corresponding to the time to reach one of these states (the first in time) in minutes.

The fire resistance limit of a structure is determined as the arithmetic mean of the test results of two samples. At the same time, the maximum and minimum value fire resistance limits of two tested samples should not differ by more than 20% (from greater value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two smaller values. In designating the fire resistance limit of a structure, the arithmetic mean of the test results is reduced to the nearest lower value from a series of numbers: 15, 30, 45, 60, 90, 120, 150, 180, 240, 360 (clause 11 of GOST 30247.0, part 1 of article 35 123-FZ).

For example, R 120 - fire resistance of 120 minutes in terms of loss of bearing capacity; REI 30 - fire resistance limit of 30 minutes in terms of loss of bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.

To normalize the fire resistance limits of load-bearing and enclosing structures, the following limit states are used (clause 8.2 GOST 30247.1):

For columns, beams, trusses, arches and frames - only the loss of the bearing capacity of the structure and nodes (R);

For external bearing walls and coatings - loss of bearing capacity and integrity (R, E), for external non-bearing walls - E;

for non-bearing internal walls and partitions - loss of heat-insulating ability and integrity (E, I);

For load-bearing internal walls and fire barriers - loss of bearing capacity, integrity and heat-insulating capacity (R, E, I).

The fire resistance limits of building structures, including those with fire protection, are determined under standard test conditions according to the methods established by regulatory documents (GOST 30247, GOST R 53307, GOST R 53308, etc.) (part 9 of article 87 123-FZ).

Fire resistance limits of building structures similar in shape, materials, design building structures who have passed fire tests can be determined by calculation (part 10 of article 87 123-FZ).

It should be noted that the fire resistance limit characterizes the behavior of the structure only under standard test conditions; the time until the structure loses its load-bearing or enclosing functions under the conditions of a “real” fire may differ from its fire resistance limit.

Previously, the methods for testing structures for fire resistance were regulated by the standard ST SEV 1000-78 and the fire resistance limits were measured in hours (a multiple of a quarter of an hour).

Standard temperature setting. To ensure comparability of test results various designs for fire resistance, performed in various laboratories, the international standard ISO 834-75 and GOST 30247.0-94 compiled on its basis prescribe them to be carried out at a certain conditional temperature regime, called "standard".

The standard thermal effect on the structure is created by burning the appropriate type of fuel in the volume of the test furnace and is controlled by temperature changes during testing. t,°C according to the law given as a continuously increasing logarithmic function time t, min:

t= 345 lg (8t + 1) + t 0 , (2.2)

where t 0 - initial temperature (usually t 0 = 20°C).

The standard temperature regime in most cases does not correspond to the temperature regimes of "real" fires, which can be very diverse both in terms of temperature values and duration of exposure (Fig. 2.1). The standard temperature regime is non-decreasing and does not reflect the initial and fading stages of the fire. The parameters of the standard temperature regime do not take into account the real value of the fire load, the volume of the premises and the area of openings in the fences.

In the US and UK, the standard temperature regime (2.2) is defined as a "pulp" fire; it most closely corresponds to the temperature regime of a fire in relatively small premises of residential and administrative buildings during the combustion of a fire load from cellulose-containing materials (wood, paper, textile materials).

In addition, several more temperature regimes have been standardized, in particular, the so-called “hydrocarbon” fire (for example, UL 1709 standard, Underwriters Laboratory, USA), corresponding to the combustion of oil, oil products or natural gas. This mode is used when assessing the fire resistance of structures of railway and road tunnels, as well as external technological installations of the oil and gas complex. When tested according to the "hydrocarbon" mode, the temperature in the fire chamber reaches 1000 ° C after 5 minutes, and the rapid increase in temperature is accompanied by a reactive impact of the flame on the overlying horizontal structures.

t NSP

Rice. 2.1. Standard temperature regime (1) and temperature regimes of "real" fires (2a, 2b, 2c); t NSP - the duration of the initial stage of the fire

It should be noted that the presence of several characteristic "standard" temperature regimes makes it possible to more fully take into account the specifics of the fire effect on structures in specific types of buildings and structures, however, comparability results of various tests. However, for the comparability of the test results, it is important to provide not only a unified regime for changing the temperature of the gaseous medium in the fire chamber, but also unified conditions for the heat exchange of the gaseous medium with the surface of the structures.

The normative term "standard temperature regime" in the literature is sometimes incorrectly called "standard fire". As noted above (clause 1.1), the normative term “fire” is defined as “uncontrolled combustion causing material damage”, and in standard fire tests, combustion is always controlled and does not lead to damage, but, on the contrary, performs a positive function.

Consider the characteristics of the limit states of structures for the fire resistance of load-bearing and enclosing structures (GOST 30247.1).

1) Loss of bearing capacity(R) occurs due to the collapse of the structure or the occurrence of limiting deformations.

For bending structural elements, the limit state occurs if the deflection reaches the value L/20 or the strain growth rate will reach L 2 /(9000h), cm× min-1 , where L- estimated span, cm; h- the estimated height of the section of the structure, cm.

For vertical structures, the limiting state is when the vertical deformation reaches 1/100 of the height or the rate of increase of vertical deformations reaches 10 mm× min-1 for specimens with a height of 3 ± 0.5 m.

2) Loss of integrity (E) occurs as a result of the formation of through cracks or holes in the structure, through which combustion products or flames penetrate the unheated surface.

During the test, the loss of integrity is determined using a cotton swab, which is placed in a special metal frame and bring it to a place where penetration of a flame or combustion products is possible, and within 10 with keep at a distance of 20 ... 25 mm from the sample surface. The time from the start of the test to ignition or the occurrence of smoldering with the glow of the swab is taken as the fire resistance limit on the basis of integrity loss E, while smoldering without glow is not a sign of loss of fire resistance.

3) Loss of heat-insulating ability (I) is defined as the result of an increase in the temperature on an unheated surface to dangerous values, which can lead to ignition of the material in the room adjacent to the fire, and thus contribute to its spread. Dangerous temperatures depend on the operating conditions of the structure.

For most load-bearing and enclosing structures in accordance with GOST 30247.1, the loss of heat-insulating ability occurs due to an increase in temperature on the unheated surface of the structure by an average of more than 140°C, or at any point on this surface by more than 180°C compared to the temperature of the structure before testing , or more than 220°C, regardless of the design temperature before testing.

For elevator shaft doors, the loss of heat-insulating ability occurs due to an increase in temperature on the unheated surface of the door leaves in comparison with the temperature of the sample before the start of the test by an average of more than 280 °C or more than 330 °C at any point on the door surface.

By the term "loss of bearing capacity of the soil" we mean the phenomenon of extrusion of the soil along the sides of the foundation with its bulging upwards; at the same time, the structure is lowered and can simultaneously squint, i.e., roll. The loss of the bearing capacity of the soil under the base of the foundation occurs when the shear strength of the soil along the sliding surface is not large enough compared to the actual stresses arising from the load (Fig. 7). The load on the foundation, at which the loss of the bearing capacity of the soil occurs, is called the ultimate load, or the highest bearing capacity; in order to avoid loss of the bearing capacity of the soil, the base must have a certain margin of safety, which is regulated by DIN 4017, hh. 1 and 2 (examples of soil bearing capacity loss studies - see). If the settlements that occur due to the compressibility of the soil under certain loads from the weight of structures represent a deformation problem, then with the loss of bearing capacity, further settlement of the soil is impossible; here, in the zone of displacement of soil from under the foundation, the problem of balance arises. The danger of loss of the bearing capacity of the soil is the greater, the smaller the width of the foundation, the depth of its laying and the shear strength of the soil; Eccentric loading of the foundation can also lead to the loss of the bearing capacity of the soil.

Under traditional construction methods with normal building loads on the ground, foundations wide enough and deep enough to determine allowable loads on the sole of the foundation, it is recommended, as a rule, to first make a calculation of the foundations for deformations and only then proceed to determine the possible loss of the bearing capacity of the foundation soils.
It should be pointed out that the risk of loss of bearing capacity of the soil under load may increase when lifting ground water and a decrease in the volumetric mass of the soil. At the first sign of the loss of the bearing capacity of the soil (tilt and distortion of the structure, horizontal shifts, heaving of the soil in the immediate vicinity of the building), countermeasures such as the installation of additional fasteners, load on the soil surface, lowering the groundwater level or strengthening the soil (for example, by injection) .

To complete the picture, we should also mention the loss of soil bearing capacity throughout the entire construction site. This phenomenon occurs when there are differences in the level of the construction area (retaining walls, slopes, steeply dipping soil layers), when the load from the building and the dead weight of the soil exceed the soil shear resistance, and the structure with adjacent soil areas shifts along the sliding surface. The reason for this is often exceptionally strong atmospheric precipitation and the resulting increase in water pressure in the pores of the soil.

If in direct connection with the construction high-rise building If soil slopes are planned, then for reasons of ensuring soil stability in the planned area, slope stability should be calculated, because there is a risk of slope shift along the sliding surface, i.e. slope sliding (DIN 4084, part 2). See slope calculation method.

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