Buildings 1 3 degrees of fire resistance. Degree of fire resistance, class of structural fire hazard

The degree of fire resistance is an important parameter that is determined when construction work and after their completion. It is very important for builders to know that a particular building structure has its own degree of fire resistance. You will learn how to determine the fire resistance of a building in this article.

The expression fire resistance refers to the ability of certain elements of a building to maintain strength in the event of a fire. Moreover, fire resistance has its own limit, which is determined in hours, i.e. specific numbers to fire danger building. It is generally accepted to denote the degree of fire resistance using Roman values: I, II, III, IV, V.

Fire resistance is divided into two types:

Actual (SOF). How is it determined? Mainly based on the result of technical and fire expertise construction structures. Also, calculations take place based on regulatory documents. The level of fire resistance is clearly regulated and known. In accordance with official information, the SOF is calculated.
Required (SOtr). This concept includes the level of fire resistance in minimum value. In order for a building to meet all safety requirements, the structure must comply with them. This degree of fire resistance is determined on the basis of regulatory documents that have industry and specialized meanings. In this case, the direct purpose of the building, its area, the availability of fire extinguishing equipment, the number of floors, etc. play a key role.

To solidify all this, let's look at an example. To make a building comply with the fire safety requirements, the SOF must be greater than or equal to SOtr. The limit of fire resistance occurs at the moment when a building completely or partially fails to perform its functionality in a fire. This happens when compartments or cracks develop in a building. The flame penetrates directly through them into adjacent rooms, the surface heats up to 140–180°C, and also if the load-bearing parts of the building are completely eliminated.

Method for determining fire resistance

Proper tests are carried out to determine the limits of fire coverage as well as the damage caused by burning. This is implemented in practice as follows: a fire is started in specially equipped furnaces. The stove is processed exclusively with refractory bricks. Kerosene is burned inside the stove using special nozzles. Using thermal vapors, the temperature inside the furnace is controlled. With all this, the operation of the nozzles must be carried out so that they do not come into contact with thermal vapors and do not come into contact with the surface of the structure. So, if we are based on basic rules, then calculating the degree of fire resistance has two tasks:

Heat engineering.
Statistical.

To determine the degree of fire resistance, it is important to first obtain an architect's design. Next, you need to adhere to the standard scheme.

As for the diagram, it looks like this:

By contacting the firefighters, they will conduct a fire resistance examination. If any deficiencies are found, they should be corrected immediately.
Already at the sketching stage, the degree of fire resistance will be indicated. And for this you should contact only competent architects who will take into account all these nuances.

In practice, this whole process, to determine fire resistance, looks like this:

The fire resistance limit is calculated in hours or minutes. The countdown should begin from the moment of a critical situation, when the structure does not withstand the test, namely, it collapses or its integrity is compromised.
For the calculation, one of five steps is taken.
Flammability level is included in these calculations/calculations different materials, which were used in the construction of the building.
For precise definition fire resistance is not enough to have superficial information. Here it is important to have a complete picture even for such structures as: additional staircases, flights of stairs, partitions and all other structures. Even the material from which these structures are made is taken into account.
It would also be useful to study additional and mandatory materials that relate to the rules for ensuring the fire resistance of reinforced concrete structures. As a basis, for example, you can take the manual to SNiP dated January 21, 1997 “Prevention of Fire”.
Thus, a wide range of planning and technological aspects are taken into account to determine fire resistance. But at the same time, we should not forget about the primary fire extinguishing means - fire extinguishers.

As a result, you need to create a list of requirements for the building, which are clarified during the fire resistance determination process. The basis is taken from the documentation and design of the building.

SNiP

In most cases, structures and buildings have type 1 walls, i.e. fire compartment. Concerning minimum threshold resistance to fire of a building, then it is equal to 25. As a result, it is allowed to use unprotected metal structures.

Building codes allow the use of drywall as facing material. This to some extent increases the fire resistance of the building.

If we talk about building materials and their degree of combustibility, they are divided into 3 groups:

Non-flammable.
Difficult to burn.
Fireproof.

If you are building a frame, it is better that it be made of non-combustible material. For buildings from grade 1 to 5, combustible materials can be used, but not in the lobbies. This is important, because in addition to everything, building materials are divided into classifications such as:

Smoke producing.
Toxic.

Below we will consider an algorithm for calculating the degree of fire resistance of a building and premises different types. Based on this, you can find out the basic requirements for certain buildings.

Residential buildings

The fire resistance of a house has 5 levels. According to these degrees, characteristics are given for each building material from which the house was built. The following are the design characteristics of residential buildings:

For residential buildings, preference is given to non-combustible materials.
Construction is best done from concrete blocks, stone or brick.
Use fire-resistant material to insulate walls, roofs and other structures.
The roofing must be made from materials that are resistant to fire, namely: slate, corrugated sheets, metal tiles or tiles.
Floors are made of reinforced concrete slabs.
If the floors are wooden, then they should be covered with non-combustible materials, for example, non-combustible slabs or plaster.
Wooden rafter system must be treated with impregnations that prevent the spread of fire.

It is not necessary to use non-combustible materials for insulation. You can use items that are resistant to fire categories G1 and G2.

Public buildings

The degree of fire resistance of public buildings is divided into 5 groups: I, II, III, IV, V. Thus, according to the class of structural fire hazard of a building, the following are determined:

I-C0.
II-C0.
III-C0.
IV-C0.
V- not numbered.

As for the permissible room height in meters and area for the fire compartment, the following data is available:

I-75m;
II-С0-50, С1-28;
III-C0-28, C1-15;
IV-CO-5-1000 m 2 ;
S1-3m-1400 m 2;
S2-5m-800 m2.

If we speak for clubs, pioneer camps, hospitals, preschools and schools, then they often use wooden partitions, ceilings and walls. Their processing must be carried out with fire-resistant materials.

Industrial buildings

Metallurgical.
Instrumental.
Chemical.
Tkatskoye.
Repair and others.

And for such establishments, the degree of fire resistance is more important than ever. Plus, some work with toxic and explosive substances that can have Negative influence human and environment.

Industrial buildings are also divided into 5 levels. Fire resistance is determined based on the used building materials. Hence the conclusion: degree fire safety industrial building directly depends on the fire resistance of the building materials used.

Warehouses

As a rule, those warehouses that are made of wooden materials. However, if they are treated with plaster and special impregnations, their degree of fire resistance increases. Concrete or ceramic tiles are also used for this purpose.

For storage facilities Intumescent paints or polymer foam are considered the most effective. Their action extends the period of raising the critical temperature.

In general, a number of measures are being taken to increase the degree of fire resistance of premises built of wood. They can also be installed aluminum doors, and instead wooden windows glass blocks.

So, it is worth noting that before determining the fire resistance of a building, it is important to take into account the characteristics and purpose of each building, as well as methods and materials that have different specifics.

6.6 Administrative buildings of enterprises

6.6.1 The degree of fire resistance, the class of structural fire hazard, the permissible height of buildings and the floor area within the fire compartment for administrative buildings of enterprises and warehouses (free-standing buildings, extensions and inserts) should be taken according to table 6.9. At
When determining the degree of fire resistance of a building, the height of the placement of classrooms, assembly halls and conference rooms should be taken into account.

6.6.2 Fire-resistant buildings with a height of no more than 28 m are allowed to be built on with one attic floor with load-bearing elements having a fire resistance limit of no less and a fire hazard class of no less than , when separated from the lower floors by fire protection overlap not lower

In this case, the attic floor must be additionally separated by fire walls. The area between these fire walls should be: for fire-resistant buildings - no more than 2000 m², for fire-resistant buildings - no more than 1400 m².
When using wooden structures attics should, as a rule, be provided with structural fire protection that ensures the specified requirements.

6.7 Public buildings

6.7.1 The degree of fire resistance, the class of structural fire hazard, the permissible height of buildings and the floor area within the fire compartment of public buildings should be taken according to table 6.9, buildings of consumer service enterprises () - according to table 6.10, trade enterprises () - according to table 6.11.

In this case, it is necessary to take into account the additional requirements provided for in this section for buildings of the corresponding functional fire hazard classes.

6.7.2 In fire-resistant buildings of the structural fire hazard class, if there is automatic fire extinguishing the floor area within the fire compartment can be increased by no more than twice as compared to those established in tables 6.9 - 6.11.

6.7.3 The floor area within the fire compartment of one-story buildings with a two-story part occupying less than 15% of the building area should be taken as for one-story buildings in accordance with tables 6.9 - 6.11.

6.7.4 In fire-resistant station buildings, instead of fire walls, it is allowed to install water deluge curtains in two threads, located at a distance of 0.5 m and providing an irrigation intensity of at least 1 l/s per 1 m of curtain length with an operating time of at least 1 hour, and Also fire curtains, screens and other devices with a fire resistance limit of at least . In this case, the specified types of fire barriers must be located in an area free from fire loads with a width of at least 4 m on both sides of the barrier.

6.7.5 In fire-resistant airport terminal buildings, the floor area between fire walls can be increased to 10,000 m², if the basement (basement) floors do not contain warehouses, storerooms and other premises with the presence of flammable materials (except for storage rooms, staff dressing rooms and premises). Storage rooms (except those equipped with automatic lockers) and dressing rooms should be separated from the rest of the basement by fire partitions and equipped with automatic fire extinguishing installations, and command and control centers should be equipped with fire partitions (including translucent ones).

6.7.6 In fire-resistant train and air terminal buildings equipped with automatic fire extinguishing installations, the floor area between fire walls is not standardized.

6.7.7 The degree of fire resistance of canopies, terraces and galleries attached to the building may be taken one value lower than the degree of fire resistance of the building. In this case, the class of structural fire hazard of canopies, terraces and galleries must be equal to the class of structural fire hazard of the building.
In this case, the degree of fire resistance of a building with a canopy, terrace and gallery is determined by the degree of fire resistance of the building, and the floor area within the fire compartment is determined taking into account the area of canopies, terraces and galleries.

6.7.8 V gyms, halls of indoor skating rinks and bathtub halls of swimming pools (with and without seats for spectators), as well as in halls for preparatory classes swimming pools and firing areas of indoor shooting ranges (including those located under stands or built into other public buildings) if their area exceeds that installed in the fire walls, they should be provided between the halls (in shooting ranges, a fire zone with a shooting gallery) and other rooms. In lobbies and foyers, if their area exceeds that installed in the fire walls, translucent fire partitions can be installed instead of fire walls.

6.7.9 Buildings of fire resistance classes, with a height of no more than 28 m, are allowed to be built on with one attic floor with load-bearing elements having a fire resistance limit of at least and a fire hazard class, when separated from the lower floors by fire protection overlap not lower. The enclosing structures of this floor must meet the requirements for the structures of the building being built on.

If available on attic floor automatic fire extinguishing installations, this area can be increased by no more than 1.2 times.

When using wooden attic structures, it is necessary, as a rule, to provide structural fire protection that ensures the specified requirements.

6.7.10 Degree of fire resistance, class of structural fire hazard and maximum height of children's buildings preschool institutions general type() should be taken depending on the largest number places in the building according to table 6.12.

6.7.11 Walls with inside, partitions and ceilings of preschool buildings educational institutions, children's health institutions and medical buildings with a hospital (class), outpatient clinics (class) and clubs (class) in buildings with a structural fire hazard class, including those using wooden structures, must have a fire hazard class of at least (15) .

6.7.12 Three-story buildings of preschool institutions may be designed in large and largest cities, except those located in seismic areas, provided they are equipped with automatic fire alarm with additional automatic transmission fire alarm directly to fire departments via telecommunication lines.

6.7.13 Buildings of specialized preschool institutions, as well as for children with visual impairments, regardless of the number of seats, should be designed with a structural fire hazard class of at least fire resistance and a height of no more than two floors.

6.7.14 Attached walking verandas of preschool institutions should be designed with the same degree of fire resistance and the same class of structural fire hazard as the main buildings.

6.7.15 Degree of fire resistance, class of structural fire hazard and maximum height of school buildings (general education and additional education children), educational buildings of boarding schools, institutions primary education(), as well as dormitory buildings of boarding schools and boarding schools at schools () should be taken depending on the number of students or places in the building according to table 6.13. The maximum floor area of a building is determined by.

1. Construction of school buildings, educational buildings of boarding schools, primary institutions vocational education, as well as dormitory buildings of boarding schools and boarding schools with a height of more than 9 m are permitted provided they are equipped with an automatic fire alarm with additional automatic transmission of a fire signal directly to the control center via wired or wireless telecommunication lines. These buildings must be located in the zone of deployment of fire departments based on the condition that the time of arrival of the first unit to the place of call should not exceed 10 minutes, and in rural settlements - 20 minutes. Driveways and entrances to these buildings should be designed based on the need to provide fire departments with a ladder or a car lift directly to each room that has window openings on the facade.

For designed four-story, as well as reconstructed five-story school buildings, at least 50% of the staircases should be smoke-free. If it is impossible to install smoke-free staircases, in addition to the estimated number of staircases, the installation of external open staircases should be provided. The number of external open stairs should be taken:

One staircase with an estimated number of students and staff on the floor above the second up to 100 people;

- at least one staircase for every 100 people when the estimated number of students and staff on the floor above the second is more than 100 people.

On the fourth floor of school buildings and educational buildings of boarding schools it is not allowed to place premises for primary classes, and the rest of the classrooms - more than 25%.

The addition of an attic floor to these buildings during reconstruction is permitted within the limits of the standardized number of storeys. However, it is not allowed to place sleeping quarters on the attic floor.

Buildings of educational buildings of secondary vocational education (fire resistance class) can be designed with a height of up to 28 m.

Academic buildings of institutions of higher professional education () should be designed with a height of no more than 28 m.

6.7.16 Buildings of specialized schools and boarding schools (for children with physical and physical disabilities mental development) should be no higher than 9 m.

6.7.17 The height of classrooms, assembly halls, conference halls and halls of sports facilities without spectator seats should be taken according to table 6.14, taking into account the degree of fire resistance, the structural fire hazard class of the building and the capacity of the hall.

6.7.18 The degree of fire resistance, the class of structural fire hazard and the highest height of buildings of entertainment and cultural and educational institutions of the functional fire hazard class should be taken depending on their capacity according to table 6.15.

When determining the capacity of the halls, the permanent and temporary seats for spectators provided for by the hall transformation project should be summed up.

When placing several halls in a cinema, their total capacity should not exceed that indicated in the table.

Load-bearing structures of coverings above the stage and hall (trusses, beams) in theaters, clubs and sports facilities should be designed in accordance with the requirements for load-bearing elements building.

For one-story fire resistance buildings, it is allowed to use load-bearing structures hall coverings with a fire resistance limit of at least . The specified structures may be made from wood treated with fire retardant compounds of group I fire retardant efficiency according to GOST R 53292. In this case, the capacity of the hall can be no more than 4 thousand seats for sports facilities with stands and no more than 800 seats in other cases, and the remaining structures must meet the requirements for class buildings.

6.7.19 Medical institutions, including those included in buildings of other functional purpose(schools, preschool institutions, sanatoriums, etc.) should be designed in accordance with the following requirements.

Buildings of hospitals (), outpatient clinics () should be designed no higher than 28 m. The degree of fire resistance of these buildings should be , the class of structural fire hazard - .

Hospitals

Hospital buildings with a height of up to three floors inclusive must be divided into fire sections with an area of no more than 1000 m², above three floors - into sections with an area of no more than 800 m² by fire departments.

Medical buildings of psychiatric hospitals and dispensaries must be no more than 9 m high, not lower than the fire resistance class of structural fire hazard.

In rural areas, buildings of medical institutions with 60 or fewer beds and outpatient clinics with 90 visits per shift may be constructed with chopped or cobblestone walls.

Operating units, resuscitation and intensive care units must be located in independent fire compartments. These blocks of two floors or more must have elevators for transporting fire departments, adapted for transporting immobile patients.

Ward departments of children's hospitals and buildings (including wards for children with adults) should be located no higher than the fifth floor of the building, wards for children under the age of seven years and children's psychiatric departments (wards), neurological departments for patients with spinal cord injury and etc., no higher than the second floor.

It is allowed to place wards for children under the age of seven years no higher than the fifth floor, provided that smoke protection and automatic fire extinguishing are installed in the building (building).

In perinatal centers, the placement of wards is allowed no higher than the fourth floor, and prenatal wards no higher than the third floor.

Homes for the elderly and disabled should be designed in accordance with the requirements for hospitals in medical institutions.

Clinics

Medical and preventive institutions without hospitals are allowed to be located in one-story buildings with fire resistance class of structural fire hazard.

Outpatient clinic buildings for children's services may be designed no higher than:

6 floors (18 m)  in large and major cities;

5 floors (15 m)  in other cases. At the same time, only administrative and domestic premises for the staff of the institution are allowed to be located on the top floor.

6.7.20 Buildings of summer recreation institutions with fire resistance, as well as buildings of children's health institutions and sanatoriums with fire resistance should be designed only as one-story buildings.

Buildings of summer children's health camps and tourist huts should be designed with a height of no more than two floors, buildings of children's health camps year-round use- no more than three floors, regardless of the degree of fire resistance and the class of structural fire hazard.

In health camps, sleeping quarters should be combined into separate groups 40 seats each. These premises must have independent emergency exits. One of the exits can be combined with a staircase. Sleeping quarters of health camps in separate buildings or separate parts of buildings should have no more than 160 beds.

For one-story placement auxiliary premises in the space under the stands or when the number of rows for spectators in the stands is more than 20, the supporting structures of the stands must have a fire resistance rating of at least a fire hazard class, and the floors under the stands must be fireproof.

Load-bearing structures of stands of sports facilities () without the use of sub-tribune space and with a number of rows of more than 5 must be made of non-combustible materials with a fire resistance limit of at least R 15 And .

The fire resistance limit of load-bearing structures of transformable stands (retractable, etc.), regardless of capacity, must be no less than .

The above requirements do not apply to temporary spectator seats installed on the floor of the arena during its transformation.

6.7.23 Library and archive buildings should be designed no higher than 28 m.

6.7.24 Buildings of sanatoriums, recreation and tourism institutions (with the exception of hotels) should be designed no higher than 28 m. partitions, no more than six floors high, with emergency exits isolated from other parts of the buildings. In this case, sleeping quarters must have an emergency exit that meets one of the following requirements:

6.7.25 The degree of fire resistance of hotels, general holiday homes, campsites, motels and boarding houses with a height of more than two floors must be , structural fire hazard class.

Sleeping quarters intended to accommodate families with children in general holiday homes, campsites, motels and boarding houses should be located in separate buildings or separate parts of buildings, separated by fire partitions, no more than six floors high, with emergency exits isolated from other parts of the buildings.

In this case, sleeping quarters must have an emergency exit that meets one of the following requirements:

The exit should lead to a balcony or loggia with a blank partition of at least 1.2 meters from the end of the balcony (loggia) to the window opening ( glazed door) or at least 1.6 meters between glazed openings opening onto the balcony (loggia);

The exit must lead to a passage at least 0.6 meters wide, leading to the adjacent part of the building;

The exit should lead to a balcony or loggia, equipped external staircase, connecting balconies or loggias floor by floor.

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

Fire resistance- this 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 the fire resistance limit.

Fire resistance limit building structures are characterized by limit states normalized according to temporary characteristics:

Load capacity (R)

Integrity (E)

Thermal insulation capacity (I)

(For example: REI120K0 – the object retains its integrity, load-bearing capacity, thermal insulation capacity for 120 minutes, non-fire hazardous)

Based on fire hazard, building structures are divided into 4 classes:

K0) Non-flammable

K1) Low fire hazard

K2) Moderately flammable

K3) Fire hazardous

Depending on the fire resistance limit, 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) Explosion and fire hazard – Combustible gases (GG), flammable liquids (FLL) with a flash point of no more than 28ºC, flammable liquids in such quantities that they can form explosive vapor-gas-air mixtures, upon ignition of which a calculated excess explosion pressure develops in the room, exceeding 5 kPa. Substances and materials capable of exploding and burning when interacting with water or with each other in such quantities that the calculated excess explosion pressure in the room exceeds 5 kPa.

Category B) Explosion and fire hazard – flammable dusts or fibers, flammable liquids (flammable liquids) with a flash point of more than 28ºС, flammable liquids in such quantities that they can form explosive dust or steam-gas-air mixtures, upon ignition of which the calculated excess pressure of explosions in the room develops, exceeding 5 kPa.

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

D1) Combustible gases, flammable liquids (flammable liquids), flammable liquids, solid flammable and difficult to combustible 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 flames.

Fire barriers

The purpose of fire barriers is to stop the spread of fire.

Fire barriers:

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

Fire partition - partitions within one room. Fire resistance limit 150 min.

Fireproof ceilings – resist the spread of fire vertically.

Fire belt - protects so that fire does not engulf the building from the outside.

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

Fire hatches.

Fire windows ( strained glass, triplex, reinforced glass)

Tambour-gateway.

Water curtains (deluge system).

Fire curtain.

Evacuation routes.

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

Escape 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 if they lead from the premises:

The first floor - directly to the outside 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 access directly to the outside or through a vestibule separated from adjacent corridors by doors.

Basement or ground floor– directly outside or onto the staircase, or into the corridor leading to the staircase. In this case, the staircase must have direct access to the outside, or be isolated from the overlying floors.

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

If a fire occurs, people must leave the building within a time determined by the shortest distance from the fire to the exit 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 escape routes must be at least 1 meter, doors on escape routes must be at least 0.8 m, and the height must be at least 2 m.

For buildings of 1, 2, 3 degrees of fire resistance, the time for evacuating people from the doors of the most remote premises to exiting outside is accepted:

From rooms located between two staircases and two external exits:

From premises of buildings of any category with access to a dead-end corridor (0.5 minutes).
External evacuation doors of buildings should not have locks that cannot be opened from the inside in case of fire.

If it is necessary to install locks on doors, in order to preserve value, it is allowed to install electromagnetic contacts that are activated automatically or manually.

When designing a building or structure, the performer sees his main task as correct selection materials used for their construction, especially from the point of view of their fire safety. The rules and regulations used in construction provide for the use of certain building materials and structures depending on the purpose of the structures. One of the determining factors taken into account is the fire resistance of the construction site.

This concept refers to the ability of materials used in construction to withstand the pressure of a flame while maintaining their characteristic consumer parameters.

These include:

enclosing properties of structural elements of a building.

Loss of resistance to loads by structural elements implies their destruction. The loss of protective properties means the formation of cracks and breaks in it that allow harmful substances from combustion into the enclosed room, or ignition of objects or substances located in it as a result of heating of the structure.

How to determine the fire resistance limit of a material? It corresponds to the time (hour) during which the described phenomenon occurs from the beginning of the fire. This value is determined by conducting appropriate experiments. The test sample is loaded into a furnace and a flame is applied to it, while simultaneously applying a design load of a different nature to it.

Next characteristic feature, which determines fire resistance, is the change in temperature at control points compared to normal. Unprotected metal structures exhibit the least fire resistance; reinforced concrete has the highest rate. The maximum possible value of the indicator is 2.5 hours.

Another fire resistance factor taken into account is the flame propagation limits, which characterize the amount of damage to a structure from exposure to fire. Measurement in centimeters and maximum length up to 40 cm.

Consequently, the degree of fire resistance of a structure is directly dependent on the corresponding indicator of the materials used in its construction.

Classification of materials according to fire resistance:

fireproof - various types bricks, building stones of various origins, metal structures;
fire-resistant - these include structural elements made of combustible materials, but protected from flames or subjected to special treatment (an example is felt impregnated with cement mortars);
combustible - easily flammable and actively burning (wood).

The degree of fire resistance of buildings and structures - classification criteria

Any structure is made from a number of components with different flame resistance parameters. Its ability to withstand fire as a whole object is called the degree of fire resistance.

In accordance with SNiP 01/21/97, this indicator is divided into 5 degrees, designated by Roman numbers I-V. To the fire resistance limits of individual elements of the structure that perform additional functions enclosing components, additional requirements are imposed, indicated by letters of the Latin alphabet:

Loss of integrity - E;
Loss of the ability to maintain integrity - R;
Fire resistance - I.

Classification characteristics are presented in Table 1:

Note to the table:

2. The procedure for defining structures as load-bearing is regulated by fire safety documents.

Two types of fire resistance are accepted:

required - this is the minimum set of conditions to ensure safe operation fire protection structures;
actual - determined at the stage design work or on a completed building on commission.

Obviously, the actual OS must be higher than the required ones.

A - premises using flammable liquids, the ignition temperature of which is below 28 ° C (gasoline, etc.).
B - buildings with combustible fibers or dust dispersed in the air (mills, grain mills, etc.).
B1-B4 - buildings where solid combustible materials are stored and processed (closed coal warehouses, workshops producing animal feed).
G - buildings where fuel combustion occurs (boiler rooms, forges).
D - buildings in which non-combustible materials are processed (food production workshops, greenhouses).

The fire resistance of residential buildings is almost similar to the parameters indicated in table. 1, there are features regarding the requirements for the number of storeys of houses, fire entrances and others. Regulatory document - SP 2.13130.2001 (set of rules). In order to find out what partitions should separate production and warehouse premises, you need

IIIa from SNiP 2.01.02-85* APPENDIX 2 Reference
SAMPLE CONSTRUCTION CHARACTERISTICS OF BUILDINGS
DEPENDING ON THEIR DEGREE OF FIRE RESISTANCE
1. Fire resistance level
2. Design characteristics

I
Buildings with load-bearing and enclosing structures made of natural or artificial stone materials, concrete or reinforced concrete using sheet and slab non-combustible materials

II
Same. It is allowed to use unprotected steel structures in building coverings

III
Buildings with load-bearing and enclosing structures made of natural or artificial stone materials, concrete or reinforced concrete. For floors, it is allowed to use wooden structures protected by plaster or low-flammability sheet and slab materials. There are no requirements for fire resistance limits and fire spread limits for coating elements, while attic wood roofing elements are subject to fire retardant treatment

IIIa
Buildings predominantly have a frame structural design. The frame elements are made of unprotected steel structures. Enclosing structures - made of profiled steel sheets or other non-combustible sheet materials with low-flammability insulation

IIIb
The buildings are predominantly one-story with a frame structural design. Frame elements are made of solid or laminated wood, subjected to fire retardant treatment, ensuring the required limit of fire spread. Enclosing structures - made of panels or element-by-element assembly, made using wood or wood-based materials. Wood and other combustible materials of enclosing structures must be subjected to fire retardant treatment or protected from fire and high temperatures in such a way as to ensure the required fire spread limit.

IV
Buildings with load-bearing and enclosing structures made of solid or laminated wood and other combustible or low-combustible materials, protected from fire and high temperatures by plaster or other sheet or slab materials. There are no requirements for fire resistance limits and fire spread limits for coating elements, while attic wood roofing elements are subject to fire retardant treatment

IVa
The buildings are predominantly one-story with a frame structural design. The frame elements are made of unprotected steel structures. Enclosing structures - made of profiled steel sheets or other non-combustible materials with combustible insulation

V
Buildings, the load-bearing and enclosing structures of which are not subject to requirements for fire resistance limits and fire spread limits

Note. Building construction buildings listed in this appendix must meet the requirements of table. 1 and other standards of this SNiP.

The most high degree fire resistance I (mausoleum).