The degree of fire resistance, class of constructive fire hazard. SNiP

1.22. * Degree of fire resistance, class of constructive fire hazard, the permissible height (according to SNiP 21-01-97) and the floor area within the fire compartment of detached buildings, annexes 1) and inserts should be taken according to table. 4 .

1 Annex - a part of a building intended for the placement of administrative and utility premises, separated from industrial buildings and premises by fire barriers. It is allowed to place (partially) engineering equipment in annexes.

In buildings of the IV degree of fire resistance with a height of two floors or more, the elements of load-bearing structures must have a fire resistance limit of at least R 45.

In buildings of III and IV degrees of fire resistance, to ensure the required fire resistance limit of load-bearing structures, only structural fire protection should be used.

In buildings of the I, II, III degree of fire resistance for the attic floor, it is allowed to take the fire resistance limit of load-bearing building structures R 45 with the provision of their fire hazard class K0, when it is separated from the lower floors by a fire-prevention ceiling of the 2nd type. In this case attic floor should be divided by type 1 fire partitions into compartments with an area: for buildings of I and II degrees of fire resistance no more than 2000 sq. m, for buildings of III degree of fire resistance - no more than 1400 sq. m. In this case, the firewall should rise above the roof in the same way as a firewall.

In the attic of buildings up to 10 floors inclusive, it is allowed to use wooden structures with fire protection, providing a fire hazard class K0.

Table 4

Fire resistance of buildings

Structural fire hazard class

Allowable height, m

Floor area within the fire compartment, sq. m., with the number of floors

1.23. * When designing buildings with a height of 10-16 floors (more than 28 m according to SNiP 21-01-97), additional requirements for these buildings should be taken into account in accordance with SNiP 2.08.02-89 * and SNiP 21-01-97.

1.24. * Extensions of I and II degrees of fire resistance should be separated from industrial buildings of I and II degrees of fire resistance by fire partitions of the 1st type.

Extensions below the II degree of fire resistance, as well as extensions to industrial buildings below the II degree of fire resistance and extensions to rooms and buildings of categories A and B should be separated by type 1 fire walls. Extensions of the IV degree of fire resistance of class C0 are allowed to be separated from industrial buildings of the IV degree of fire resistance of classes C0 and C1 by fire walls of the 2nd type.

1.25. * The inserts should be separated from the production premises by type 1 fire walls.

Inserts in buildings of I, II degrees of fire resistance of classes C0 and C1, III degrees of fire resistance of class C0 may be separated from industrial premises of categories C, D and D by fire partitions of type 1, in buildings of III degree of fire resistance of classes C1 and IV degrees of fire resistance of classes C0 and C1 - type 2 fire walls.

Buildings should be taken with no more than two floors and separated from industrial premises of categories C, D, D by fire partitions with a fire resistance limit of EJ 90 and type 3 fire ceilings.

The total area of ​​the inserts allocated by type 1 fire partitions and type 2 fire walls, as well as built-in and industrial premises, should not exceed the area of ​​the fire compartment established by SNiP 31-03-01.

1.26. The corridors should be divided by type 2 firewalls into compartments with a length of no more than 60 m.

1.27. From the corridors located in the aboveground and basement floors and without natural lighting, with any area and dressing rooms with an area of ​​more than 200 m 2, it should be provided exhaust ventilation for smoke removal in accordance with SNiP 2.04.05-91 *.

1.28. * In buildings, annexes, inserts and outbuildings, ordinary staircases of the 1st type should be provided, except for the cases specified in clause 1.23.

In buildings of I and II degrees of fire resistance with the number of floors no more than three 50% of staircases, it is allowed to provide type 2 with upper natural lighting; in this case, the distance between the flights of the stairs should be at least 1.5 m. In these buildings, the main stairs can be designed open to the entire height of the building, provided that the remaining (at least two) stairs are placed in ordinary staircases of the 1st type. At the same time, lobbies and floor halls, in which open stairs are located, should be separated from adjacent rooms and corridors by type 1 fire partitions.

1.29. Glazed doors and transoms above them in interior walls staircases are allowed to be used in buildings of all degrees of fire resistance; at the same time, in buildings with a height of more than four floors, glazing should be made of reinforced glass.

1.30. * Cladding and finishing of surfaces of walls, partitions and ceilings of halls with more than 75 seats (except for halls in buildings of the V degree of fire resistance) should be provided from materials of flammability groups not lower than G2.

1.31. Automatic fire alarm should be in separate standing buildings and annexes with more than four floors, in inserts and built-in - regardless of the number of floors in all rooms, except for rooms with wet processes.

Any building or structure is a collection of individual structural elements. Moreover, each such element has a certain degree of fire resistance, sometimes greater, sometimes less in comparison with the rest of the building structures.

General concept of the degree of fire resistance

So what is it - the degree of fire resistance of a building? This is the ability of a building as a whole to avoid destruction and maintain stability in the face of open fire - fire. Each building has its own quality characteristics in terms of the degree of fire resistance.

This classification of an object is determined taking into account the difference in fire resistance indicators of its individual constituent structures. When determining the general degree of fire resistance of a structure, its level is indicated by Roman numerals: I, II, III, and so on. In total, according to SP 2.13130.2012 (Code of Rules), there are five degrees - I, II, III, IV, V (see the table), which are assigned depending on the fire resistance limits of all the main elements of the building, taking into account their functional load.

Requirements for individual building elements

In SP 2.13130.2012 and other regulatory enactments, additional or increased requirements for fire resistance are imposed on some elements of structures. For example, this concerns load-bearing walls and similar enclosing structures. To determine the degree of fire resistance of such building elements, the following parameters are taken into account:

Loss of carrying capacity (R);

Integrity violation (E);

Loss of insulating ability (I).

Determination of the actual and required fire resistance of buildings and structures

There is an actual as well as a required degree of fire resistance.

Actual. Determined on the basis of an act of fire-technical expertise using the regulatory framework (the same joint venture - the Code of Rules). Moreover, experts are quite capable of giving an unambiguous conclusion not only on buildings and structures already built, but also on those that are at the design stage. In the table above, you can find out the fire resistance limits of structural elements of the building, which are used to determine the actual degree of fire resistance of the building as a whole.

Required. This is the minimum permissible degree of fire resistance of a building to meet all fire safety standards. Determined on the basis of specialized regulations and industry documents (norms, orders, etc.), depending on the total area of ​​the building, its purpose, number of floors, explosion category, availability of equipment for primary fire extinguishing systems, etc.

How to determine the degree of fire resistance of a building, on what factors does the fire resistance limit depend? Any architect or owner should know the answers to these questions. With this knowledge, it is easy to design a fire escape route, emergency exit position, etc. But in our time there are many architectural solutions for the construction of buildings of the same type, so determining the fire resistance of each can cause some difficulties.


What is the fire resistance of a building and why is it determined?

Buildings with a capacity of more than 100 seats and a height of 3 m must have C1 fire safety and III degree of fire resistance of the building. How to determine the number of seats? This indicator depends on the population of the area. According to SNiP, the number of places in the nursery is allowed to increase to 120 per 1000 residents of the district, on average 60-90.
Gardens with a capacity of more than 150 places must have II degree of fire resistance and C1 fire safety. With a height of at least 6 m.

Kindergartens with more than 350 children's places and a height of 9 m have a level II or I level of resistance and C0 or C1 safety.

Determining the resilience of the district hospital

It is already known how to determine the degree of fire resistance of a building, if it is a school or Kindergarten and what to do with hospitals? They have their own rules and regulations.
For public buildings of this type, the maximum permissible height is 18 m, while the degree of fire resistance should be I or II, and safety C0.
At a height of up to 10 m, fire resistance decreases to II, and structural safety to C1.


If the height of the building is 5 meters or less, then the degree of fire resistance can be III, IV or V, and the level of structural safety, respectively, C1, C1-C2, C1-C3.
There is nothing more difficult in studying the topic "The degree of fire resistance of a building", how to determine the RB (district hospital) level of security.

Output

It is not that difficult to actually determine the fire resistance of a building. Difficulties arise only at the practical stage, but this is less than half and even less than a third common work... After studying the architectural plan, the state of the building as a whole and the state of the supporting structures, the tester has already done most of the work!

When constructing important objects, it is necessary to approach the choice of materials and technologies with great responsibility. One of the important parameters is the ability of all components of buildings to withstand fire. How to determine the degree of fire resistance of a building, what factors affect the limit of this property? Only a specialist can answer these questions. It is thanks to the knowledge gained during training at higher educational institution, you can think over the escape routes in advance, correctly position the fire exits and do everything possible so that the building and all its inhabitants are not damaged during a fire.

Nowadays, there are many newest solutions used in architecture. That is why determining the fire resistance of buildings and structures causes some difficulties.

Fire safety, the conditions for the propagation of flame in them directly depend on the flammability and the ability to resist fire of the materials that were used during construction and decoration. These qualities for building components are established even during the design of the object. Much depends on the category of fire and explosion hazard of the premises located in a particular building. But first things first, so that you can accurately determine the degree of resistance to fire of any structures.

What is meant by the degree of fire resistance?

Before answering the question of how to determine the degree of fire resistance, you need to figure out what it is all about. This is an indicator that allows you to determine the possible resistance of a particular room to the effects of fire. It can be calculated according to the rules of SNiP. This is a general provision that makes it possible to give an accurate assessment and establish the level of security of a building for any purpose, as well as the materials from which it was erected.

The value of fire resistance determines how quickly a fire can spread in a certain room. And this directly affects the safety of people. All types of buildings, depending on the resistance to fire and the speed of fire spread, are divided into 5 categories.

Rules for determining the fire resistance of buildings

To correctly determine the fire resistance of a particular structure (be it a residential building or an industrial building), you need to have:

  • architectural plan;
  • rules for ensuring durability and safety from fire of reinforced concrete structures;
  • a guide that allows you to determine the limits for these parameters of structures to SNiP;
  • manual to SNiP - helping to prevent the spread of the fire source.

The endurance limit of any construction object is determined by the time of exposure of the test structure to a fire. When the state reaches one of the limits, the fire is artificially stopped. Before proceeding with testing, it is necessary to carefully study the documents for the structure. This includes what building materials were used, the characteristics of the building, possible estimates of fire resistance and other points.

It is necessary to carefully study the presence or absence of information on the application in the documentation for the structure. modern technologies that could help improve the fire resistance level. During the preliminary consideration of the structure of the structure, all premises should be examined, including utility rooms, stairways and others. It is possible that completely different materials were used during their construction. Indeed, often builders, in order to reduce the amount of the estimate, save money when arranging utility rooms and staircases, which leads to a sharp decrease in their strength and resistance to fire. In extreme situations, it is these areas of the building that cause the fire to spread.

In the construction of modern buildings, architects often use innovation. But in most cases, certain areas are not as strong as the rest of the structure. Therefore, this point is important to consider. It is worth taking all the necessary measures in advance in order to quickly cope with the fire in the event of a fire:

  • hire a fire brigade;
  • check the serviceability of hoses and fire extinguishers.
  • equip a fire shield.

Only after all safety standards are fully observed can you start working. After preparatory activities you can move on to practical.

What is SNiP?

Often answering the question of how to determine the degree of fire resistance of a building, one has to deal with such a definition as SNIP. But what is it?

"Construction Norms and Rules" is a collection of legislative documents, which were previously approved by the authorities of the Russian Federation, and regulate the rules for the construction of urban and rural buildings. In addition, projects developed by architects and engineering searches are included in such a document.

After a thorough study of such paper, any owner will be able to independently understand all the drawings and determine the state of the structures. In any situation, you need to use special reference books. This is the only way to easily determine the 2nd degree of fire resistance of buildings or any other. This is exactly what special documentation is required for.

But how to determine SNiP for a specific building using reference manuals and a building passport? Experienced specialists in this case carefully read the code of SNiP (01.21.97) "On the safety of structures and buildings during a fire." And in order to properly prepare for the tests, it is necessary to carefully study another SNiP (03/31/2001), which describes in detail all the laws relating to the construction and operation of buildings in the Russian Federation.

What are the degrees of fire resistance of buildings?

As we said earlier, there are 5 degrees of fire resistance, and they depend on the degree of ignition and the resistance limit of the main structures. Below is a table of fire resistance of buildings and structures.

Fire resistance

Structural characteristics

1 degree of fire resistance of the building

Structures with supporting and enclosing structures, erected using artificial and natural stones, concrete or reinforced concrete using non-combustible types of materials in the form of sheets or slabs.

Identical to grade 1, but only steel structures are allowed to be used in the coatings of buildings.

Structures with supporting structures and fences made of stone materials, reinforced concrete and concrete. Overlappings can be wooden, protected from above with a layer of plaster, non-combustible sheet materials, as well as slabs. There are no special requirements for coatings in terms of fire resistance, but in the attic, all wooden structures must be treated with a special protective compound against fire.

The buildings are mainly of frame type. All structures are made of unprotected steel. Fences made of steel profiled sheets and other sheet materials that are not afraid of fire.

Mostly buildings on one floor with a frame structure. The frame is made of wood that has previously passed special processing to protect against fire. Piecewise pre-assembled panel fencing made of wood or materials. All timber structures must be reliably protected from the effects of high temperatures.

Structures with load-bearing structures and fences made of wood and other flammable materials, which are protected from fire by a layer of plaster or slab-shaped materials. There are no special requirements for overlapping. But the elements of the attic made of wood must be thoroughly treated with fire retardants or materials.

The buildings are mainly on one floor with wireframe... The frame is made of steel, and the fence is made of profiled sheets or other elements with a combustible insulation.

Structures that do not have special requirements for the qualities of fire resistance and fire propagation.

Types of fire hazard of building structures

All construction projects must meet fire safety requirements. Determines the degree of fire resistance of the building FZ 123, which stipulates all the requirements and criteria. Today, there are 4 classes of fire hazard of construction objects:

  • K0 is not fire hazardous.
  • K1 - low fire hazard.
  • K2 - moderately fire hazardous.
  • K3 is fire hazardous.

When determining the fire resistance of buildings, it is necessary to take into account:

  • number of floors;
  • functional fire hazard;
  • the area of ​​the building and the fire compartment;
  • fire hazard of processes taking place inside the building;
  • building category;
  • distance to nearby buildings.

When all these factors are taken into account, it will not be difficult to determine the fire resistance.

Objectives and scope of technical regulation

As mentioned earlier, it is impossible to determine the stability of any structure in relation to fire without FZ 123, but besides this, it is imperative to take into account SP 2 13130 ​​2012. The degree of fire resistance of buildings should be determined when:

  • design, construction, overhaul, during the reconstruction, changes in the functional purpose;
  • development, adoption and implementation of the Federal Law on technical regulations, which include fire safety requirements;
  • at the stage of developing documentation for protected objects.

If all these requirements are met, it will not be necessary in the event of a fire to find out where the mistake was made.

Instructions for determining the limit of fire resistance

Those who are going to start construction ask themselves one of the most important questions: "How to determine the degree of fire resistance of buildings?" Using our instructions, anyone can cope with this task. Even during the execution of project documentation, the calculated indicator for each parameter is indicated. But it is better to check and compare all the data yourself, guided by SNiP. The limit for this property can be considered the time that elapses from the beginning of the action of fire on the structure and until the moment when critical changes appear. General indicator determined by the maximum values ​​of durability. At the same time, this must be taken into account for all elements: partitions, vertical structures, which are load-bearing, doors, windows and others.

The calculation should include information on the level of ignition of building materials.

Analyze the entire building project in detail. Information about the main elements used in construction may not be enough to obtain more realistic data. Therefore, it is better to review and check everything personally, exploring each site, including utility rooms and stairways. To study this whole mechanism in detail and carry out the calculations correctly, you need to use the manuals for SNiP.

How can the fire resistance of a building be increased?

So that the bearing supports could withstand the fire, and everyone who is in the building at this time could escape, there are several methods of increasing fire resistance. First of all, it is worth choosing the right materials that have passed certification and fully meet fire safety standards. Fortunately, there are plenty of such raw materials currently on the construction market. But people's lives depend on skillfully and, one might say, professionally carried out measures to protect buildings from fire.

Today, a huge variety of high-quality materials from European and domestic manufacturers are presented, with the help of which you can protect against fire.

How to carry out high-quality fire protection?

The best fire protection is concreting and brickwork. Another important function is structural reinforcement. Brick is mainly used for vertically located structures; reinforcement of the concrete layer is also used. Its thickness is selected individually for each object. Cladding made of sheets, plates and screens is used to protect columns, beams, posts. It is also good to use plaster.

Finishing is good in that it provides reliable protection from fire, but also inexpensive. But there are also disadvantages. Cladding requires special skills and the thickness of the layer must be chosen correctly.

Finally

It is not difficult to determine the 3rd degree of fire resistance of buildings or 5. Difficulties, of course, can arise. But if you have everything at hand Required documents, a set of rules, the difficulties will be quickly resolved. After studying the plan, the state of all building structures, it can be expensive to determine the fire resistance, but not so difficult. The main thing is to adhere to safety precautions during testing, be careful and be careful, control the temperature in the oven.

In modern times, with such a huge scale of construction, it is important that the fire resistance of buildings and materials from which residential buildings, offices and important institutions are constructed comply with the standards. The life of citizens depends on it. It is no secret that many accidents occur as a result of the use of unsuitable materials and violations of construction techniques.

SNB.2.02.01-98 "Fire-technical classification of buildings, building structures and materials"

Fire resistance is the ability of building structures to resist the effects of fire for a certain time while maintaining operational functions.

Fire resistance is characterized by a fire resistance limit.

Fire resistance limit of building structures is characterized by the limit states normalized by time criteria:

    Bearing capacity (R)

    Integrity (E)

    Thermal insulating capacity (I)

(For example: REI120K0 - the object retains its integrity, load-bearing capacity, heat-insulating capacity for 120 minutes, non-flammable)

By fire hazard, building structures are divided into 4 classes:

K0) Non-flammable

K1) Low fire hazard

K2) Moderately flammable

K3) Flammable

Depending on the limit of fire resistance, 8 degrees of fire resistance are established (1st is best, 8th is worst)

1st degree of fire resistance: load-bearing walls R120K0, internal walls RE150K0, flights and landings RE30K0.

Category A) Explosive and flammable - Combustible gases (GG), flammable liquids (FL) with a flash point of not more than 28 ° C, flammable liquids in such an amount that they can form explosive vapor-gas-air mixtures, when ignited, the calculated excess pressure of the explosion develops in the room, exceeding 5 kPa. Substances and materials that can explode and burn when interacting with water or with each other in such an amount that the estimated excess pressure of the explosion in the room exceeds 5 kPa.

Category B) Explosive - flammable dust or fibers, flammable liquids (FL) with a flash point of more than 28 ° C, flammable liquids in such an amount that they can form explosive dust or vapor-gas-air mixtures, when ignited, the calculated excess pressure of explosions in the room is exceeding 5 kPa.

Category B) (Divided into B1, B2, B3, B4) Fire hazardous - highly flammable liquids (FL), flammable liquids and hardly flammable liquids, solid flammable and hardly flammable substances and materials (including dust and fibers), capable of interacting with water, oxygen, air or burn with each other.

D1) Flammable gases, flammable liquids (FL), flammable liquids, solid flammable and hardly flammable substances and materials used as fuel.

D2) Non-combustible substances and materials in a hot, incandescent or molten state, the processing of which is accompanied by the release of radiant heat, sparks and flame.

Fire protection barriers

Purpose of fire barriers: to stop the spread of fire.

Fire protection barriers:

    Fire wall - perpendicularly crosses the entire building, starting from the zero mark and ending with the roof, and it protrudes above the roof (0.3-0.6) m. The fire resistance limit is 150 minutes.

    Firewall - it divides within the same room. Fire resistance limit 150 min.

    Fireproof ceilings - resists the spread of fire along the vertical.

    Fire belt - protects against fire from engulfing the building from the outside.

    Fire doors - can be metal, wood upholstered with sheet steel.

    Fireproof hatches.

    Fireproof windows (tempered glass, triplex, wired glass)

    Tambour gateway.

    Water curtains (deluge system).

    Fire curtain.

Escape routes.

SNB 2-02-01 "Evacuation of people from buildings and structures in case of fire"

Evacuation routes serve to ensure the evacuation of all people in the building through emergency exits without taking into account fire extinguishing equipment and smoke protection.

Exits are evacuation exits if they lead from the premises:

    On the first floor - to the outside directly or through the corridor and vestibule, corridor and staircase to the outside.

    Any above-ground floor - directly into the staircase or into the corridor leading to the staircase, which has an exit directly outside or through the lobby, separated from the adjoining corridors by doors.

    Basement or basement floor - directly outside or into the staircase, or into the corridor leading to the staircase. In this case, the staircase must have an exit directly to the outside, or be isolated from the overlying floors.

    To an adjacent room on the same floor, provided with exits, according to points a, b, c.

In the event of a fire, people must leave the building within a time period, which is determined by the shortest distance from the place of fire to going outside.

The number of emergency exits from buildings is determined by calculation, but is at least two.

Elevators are not escape routes.

The width of the escape routes must be at least 1 meter, and the doors on the escape routes must be at least 0.8 m, the height must be at least 2 m.

For buildings of 1, 2, 3 degrees of fire resistance, the time of evacuation of people from the doors of the most remote premises before going outside is taken:

    From rooms located between two stairwells and two external exits:

  1. From premises of buildings of any category with access to a dead-end corridor (0.5 minutes).

    External escape doors of buildings should not have locks that cannot be opened from the inside in case of fire.

If it is necessary to arrange locks on the doors on condition of preservation of value, it is allowed to install electromagnetic closures that are triggered automatically or manually.

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