Three-story house located on the site in such a way that the neighbor's house is very close, just 2 meters from the roof overhang of the first house. Both houses are wooden, covered bitumen shingles. Baths and outbuildings are attached to each house.
In the event of a fire, will one house be saved if the other catches fire? Was it possible to build houses so close to each other?
To understand what kind of house you can build according to fire regulations and where on the site you can place the house relative to other buildings and neighboring houses, what should be the degree of fire resistance of a residential building, look carefully at the fire resistance table of buildings.
Fire resistance of a residential building (table):
The degree of fire resistance of a residential building is I. The house must be built of brick, stone, and concrete blocks. Insulation must be made with non-combustible materials. Floors must be made of reinforced concrete slabs. The roof must be made of non-combustible materials - natural tiles, metal tiles, slate, corrugated sheets.
The degree of fire resistance of a residential building is II. The house is built of bricks and blocks. Floors can be made of wood protected with plaster or non-combustible board materials. The rafter system, when made of wood, must be treated fire retardant impregnations. Insulation can be made with non-flammable materials, or materials with fire resistance ratings G1 and G2.
The degree of fire resistance of a residential building is III. Frame house built on a metal frame. All frame elements are metal, including the rafter system. Insulation in a metal frame - non-flammable or group G1 or G2. The cladding of such a house is made only of non-combustible sheet material, for example metal siding.
The degree of fire resistance of a residential building is IIIb. Single storey frame house on wooden frame with fire retardant treatment. All wooden elements The frame and cladding of the house are treated with fire retardant impregnations. Insulation – non-flammable or groups with fire resistance limit G1 or G2.
The degree of fire resistance of a residential building is IV. The house is built on a wooden frame with the frame and walls protected by plaster coatings. Fire retardant treatment should only be applied to elements attic floor– logs and sheathings. The cladding can be made of any material; there are no fire resistance requirements for cladding in this category.
The degree of fire resistance of a residential building is IVb. The same as grade IV, only the frame is metal and the house is one floor. Enclosing structures must be made of sheet metal or any other non-combustible materials. Insulation can be used from groups G3 or G4.
The degree of fire resistance of a residential building is 5. All other buildings that do not fall into the above categories and for which there are no requirements for the limit of fire spread and fire resistance.
According to this table, you can determine the fire resistance of a residential building, assign each house to a specific category based on the materials used, and plan the development of the site accordingly. If the houses have already been built, then fire safety measures can be organized - sheathing with non-combustible materials, insulation with non-combustible insulation, and the like.
This will increase the fire resistance of a residential building, even if it is made of wood or if this house is built high - 3 floors or more.
Fire resistance level of buildings and structures
Fire resistance increases the chances of a building surviving and maintaining human life. Fire resistance depends on the materials from which the building is constructed and the purpose of the structure in relation to the functions performed. Exist different categories degrees of fire resistance, which are numbered in Roman numerals from one to five.
Industrial and warehouse buildings are endowed with high resistance to fire, because they have a high degree of fire potential. Shopping and entertainment centers are highly exposed to the risk of fires, where there is a high chance of fires and fire spreading throughout the area. Now the degree of fire resistance of a building determines the basis fire safety.
SNIP
Basically, buildings and structures have type I fire walls, or more precisely, fire compartments. The degree of fire resistance is determined by the minimum limit of fire resistance of materials and by the rate of capture of the territory, that is, structures and frames.
The minimum fire resistance threshold for a building is 25. Therefore, unprotected metal structures can be used for this. For all types of buildings building codes allow lining with plasterboard materials to increase fire resistance.
Typically, the degree of fire resistance is determined by the type of purpose of the building:
- by fire or explosion category fire danger.
- The fire compartment must be located within the boundaries of the floor area.
- Number of floors of the building.
By combustibility Construction Materials are divided into the following groups:
- Non-flammable
- Difficult to burn
- Fireproof
When installing frame structures, non-combustible materials should be used. Combustible materials can be used for buildings of fire resistance class I-IV, except for lobbies.
Building materials are classified according to toxicity and smoke production during combustion of products.
Algorithm for determining fire resistance for different types of buildings
Residential buildings (houses)
The fire resistance of a house has five degrees, which characterize each material from which the house is made.
Structural characteristics of a residential building:
- Houses in this fire resistance class require work to be done using non-combustible materials. The building should be made of brick, concrete blocks or stone. Fire-resistant materials are required for insulation. The roof must be made of tiles, metal tiles, corrugated sheets or slate, that is, fire-resistant materials. For floors it is necessary to use reinforced concrete slabs.
- The building is made of blocks and bricks. The floors may be made of wood, but covered with protective materials such as plaster or non-combustible boards. The wooden rafter system must be treated with impregnations that protect against fire. For insulation, it is not necessary to use non-combustible materials; you can use items with fire resistance limits G1, G2.
III. The construction must be made from metal frame, this also applies rafter system. insulation should be performed with fire resistance limits G1, G2 or fire-resistant. For external cladding Non-combustible materials must be used at home.
IIIb. Cottage executions on frame basis should be impregnated with fire-resistant substances. The sheathing is also impregnated, the insulation is from groups G1, G2 or non-flammable materials.
- A wooden frame protected by materials in the form of a plaster coating. Fire resistant treatment must be applied to attic floors. The house's siding does not move forward special requirements, so it can be made from any materials.
IVb. Similar to the previous group, only the building is one-story. Metal materials should be applied for frame structures. Enclosing structures must be made of combustible materials. Materials of groups G3 and G4 must be used when laying insulation.
- All categories of houses not included in this list are included. There are no special requirements for this group in terms of their resistance to fire.
Public buildings
Mostly residential buildings classified according to functional fire safety into the following categories:
- F 1.2 Dormitories
- F 1.3 Multi-apartment buildings, including families living with disabled people.
Through passages in houses must be 3.5 m wide, and the height must be at least 4.25 m. It is necessary that through through passages along staircase were placed at a distance from each other no more than 100m. The top floor determines the height of the structure, including the attic, not including the technical floor, located at the very top of the building. The difference in the boundaries of the passage points for fire-fighting vehicles between the top and bottom determines the height of the floor of the building.
The next class of buildings F 1.3 can be determined based on the bulleted list, as well as the maximum allowable area of the fire compartment located on the floor.
- Fire resistance levels of public buildings are divided into five groups– I, II, III, IV, V.
- Based on the structural fire hazard class of a structure, the following is determined: I- C0, II-C0, C1, III- C0, C1, IV-C0, C1, C2, V- not numbered.
- The maximum permissible height of the structure in meters, as well as the area for the fire compartment located on the floor: I-75m-;II-C0-50, C1-28; III-C0-28, C1-15; IV-CO-5-1000m2, S1-3m-1400m2, S2-5m-800m2. Next are the permissible height figures without numbering (C), 3m-1200m2, 5m-500m2, 3m-900m2; V-not numbered - 5m-500m2 and 3m-800m2.
Inside the buildings that contain wooden walls, ceilings, and partitions should be treated with fire-resistant materials such as varnish and plaster. This applies to buildings such as schools, preschools, hospitals, pioneer camps and clubs.
For bus stations, the internal area does not need to be limited, because there is a fire extinguishing system. Relative to the first, the area of the bus station can be increased to 10,000 m2, if at the bottom of the station there is basement rooms there are no storage or storage rooms.
Industrial buildings
Industrial buildings are defined as structures producing goods in the form of semi-finished products, as well as finished products. Production is divided into many industries and each has its own nuances and subtleties; they include repair, weaving, chemical, tool, metallurgical, mechanical assembly and many others.
The degree of fire resistance of production facilities is especially important, since some work with explosive or toxic substances that can harm the environment natural environment and directly to the person.
Industrial buildings are classified into five levels. Following the flammability and fire resistance limits of the main structures and the materials from which they are made, the degree of fire resistance of the building is determined.
Buildings of the 1st class are determined by the 2nd class, for the 2nd class they are determined by the 3rd class. For III and IV, numbering is not required. Therefore fire safety industrial buildings directly depends on the fire resistance of building materials.
Based on their structures and architectural structures, industrial buildings are divided into single-story, multi-story and mixed-story.
Warehouses
The limit of resistance to fire and its spread throughout the territory determines the degree of fire resistance of structures. Consequently, different building materials have been developed that determine the degree of fire resistance.
The most vulnerable are warehouse premises from wooden materials, but the degree of fire resistance can be increased through various impregnations, as well as plaster. Fire resistance of warehouses is passive protection that prevents or reduces the spread of fire inside the structure.
To increase the degree of fire resistance metal structures use fireproofing treatment, this can be plaster, ceramic or concrete tiles.
Intumescent paints are considered very effective because they allow more time for the temperature to reach a critical temperature. Also, to increase fire protection, it should be treated special impregnations
Windows often use polymer foam or replace the openings with special glass blocks. Doorways should be made of non-combustible metal substances, such as aluminum. These measures can increase the fire resistance limit warehouse
and protect human life.
SNIP laws developed make it possible to determine the degree of fire resistance of buildings and structures, to understand to what class and type they belong. These standards give a clear description of the building and make it possible to determine the safety of the structure necessary for labor protection or the preservation of human life. Consequently, according to the standards and purpose of the building, appropriate materials are used, which are necessary for the implementation of frame structures, insulation and cladding of the building., which allows you to assess the established level of safety of any building for its intended purpose, as well as the materials from which it is built.
The rate of fire spread per unit of time in a particular room depends on the fire resistance parameters. All types of buildings and structures, depending on their resistance to fire and the speed of fire spread, are divided into five categories and are designated by Roman numerals.
Based on their flammability, structures are classified as follows::
- Fireproof;
- Difficult to burn;
- Combustible.
This classification is conditional, since within the same building, different rooms can be made from different materials. Residential or industrial buildings in the construction of which fireproof materials were used are considered fireproof.
Difficult to burn are those that are made of fireproof or combustible materials that have additional fire protection. Eg wooden door, covered with special varnish, asbestos and roofing steel. Combustibles are those that ignite easily and the rate of fire spread is high.
How to determine the fire resistance of a building
The basis for determining the degree of fire resistance of any room is the time from the moment of fire construction materials, until obvious defects appear in these structures.
- The appearance of cracks or damage to the integrity of the surface, which may cause the penetration of flames or combustion products;
- Heating of the material by more than 160 C, or more than 190 C, at any point on the surface;
- Deformation of the main components, which causes its collapse, thus losing the bearing capacity of the supporting structures.
Reinforced concrete supporting structures are considered to be the safest in terms of fire, provided that the concrete contains cement with a high level of fire resistance. Unprotected metal materials are considered to be the least fire hazardous.
Classification of materials and their fire resistance
The actual degree of fire resistance depends on the materials that were used in the construction of buildings and structures.
All building materials are classified according to the following characteristics:
- Release of toxic substances;
- Flammability;
- Flammability;
- Smoke generation;
- Spread of fire over the surface of a structure.
According to GOST 30244-94, non-combustible materials fire resistance indicators are not standardized and may not be determined.
Fire resistance standards are determined by the time of deformation of the structure.:
- 300 min. – bricks made of ceramics or silicates;
- 240 min. – concrete whose thickness exceeds 250 mm;
- 75 min. – wood with a gypsum coating of at least 20 mm thickness;
- 60 min. – standard Entrance door, which is pre-treated with a fire retardant;
- 20 minutes. - metal structures.
The reason for the destruction of ordinary concrete is the presence bound water, the mass fraction of which is about 8%. Metals have a high degree of flammability because at temperatures above 1000 C, they transform from solid to liquid.
Hollow brick and concrete with a porous structure are among the most resistant to action elevated temperatures and open flame. Buildings made from these materials have I-II degrees of fire resistance and structural fire safety class.
Rules for determining the fire resistance of buildings
The degree of fire resistance and fire hazard class are determined by authorized services. Any production has a degree of fire resistance and a structural fire safety class
According to SNiP 21.01-97, all buildings can be divided into 5 main degrees of fire resistance of structures. The required degree of fire resistance is always indicated in the passport of the boiler room, industrial or residential building. And so fire resistance is divided:
| Fire resistance degree | Characteristic |
| I | All external walls must be made of synthetic or natural stone, porous concrete or reinforced concrete. Floors are made of slabs or other non-combustible materials, which must belong to the protection class: “non-combustible”. The safest building in terms of the possibility of a fire occurring and spreading. High level security. These necessarily include boiler rooms. |
| II | This degree of fire resistance is similar to I, the difference lies in the possibility of using open steel structures. (Materials for a brick house). Brick houses have a fire resistance class of II and a structural fire safety class |
| III | The third level of safety assumes that all main elements of industrial buildings must be made of synthetic or natural stone. wooden floors possible if they are covered with plaster or plaster. Can also be installed as a covering sheet materials, belonging to the class “difficult to burn”. Coating elements are not standardized for the occurrence and spread of fire, but wooden roof slabs are treated with special solutions, which prevent fire. |
| III a | Buildings constructed according to the type of frame structures that are made of “bare” steel. Enclosing profiles made of steel or other fireproof materials. It is possible to use low-flammability insulation materials. |
| III b | Wooden houses on one floor have a fire resistance class of III b and a structural fire safety class. All wooden elements are subject to fire retardant treatment, which should limit the spread of fire. Boundary structures are made of wood or composite materials containing wood. All fencing structures must undergo fire retardant treatment in order to prevent possible fire and overheating of the structure. It is unacceptable to erect such ceilings close to a source of heat and high temperatures. |
| IV | 4 degree of fire resistance requires construction wooden house. Fire protection is carried out by applying gypsum, plaster or other insulating materials. Coating elements do not have special requirements for the occurrence and spread of fire, but wooden roof slabs must undergo fire retardant treatment. |
| IV a | Single-story buildings made of steel that do not have protective insulating coatings. The ceilings are also made of steel, but with insulating fireproof materials. |
| V | This degree of fire resistance of buildings includes all objects (industrial, residential) for which there are no special requirements regarding the fire resistance threshold and ignition rate. |
SNiP
People wondering: what is the degree of fire resistance of a building and how to determine it, should understand that all relevant manipulations to determine the degree of fire resistance from a container to a large industrial building are carried out by fire services.
According to generally accepted rules SNiP, boiler houses have I degree of fire resistance and structural fire safety class. All furnaces must be separated from the main boiler room by fireproof partitions of appropriate thickness, which depends on the volume of the fuel chamber.
If the boiler room uses gaseous or liquid fuel, then the room is equipped with materials that can be quickly dismantled. SNiP rules for a boiler room, depending on the daily heat production, normalize the thickness of both main and interior walls, as well as the materials from which they are made. In terms of fire resistance, such buildings belong to the first group.
The degree of fire resistance of buildings, the required fire resistance limits PTR of building structures. Fire hazard of building materials
DEGREE OF FIRE RESISTANCE OF BUILDINGS, REQUIRED LIMITS OF FIRE RESISTANCE OF PTR BUILDING STRUCTURES.
FIRE HAZARD OF BUILDING MATERIALS.
For residential buildings, the degree of fire resistance of the building is determined according to SNiP 31-01-03 depending on the height of the building (Table 5). For example, for buildings up to 50 m high with a floor area up to 2500 m2, the fire resistance degree should be I.
Knowing the degree of fire resistance of the building according to the table. 6 of SNiP 21-01-97* “Fire safety of buildings and structures” defines the required fire resistance limits PTR of all building structures.
The fire resistance limit of building structures is set by time (in minutes) until the onset of one or successively several signs normalized for a given structure: for load-bearing structures based on loss of bearing capacity R, in min.; for external non-load-bearing walls, floor slabs according to E - loss of structural integrity, i.e. until through cracks form, in minutes; for floors, floorings, internal walls according to J - loss of thermal insulation capacity, when on the side of the floor opposite from the impact of the fire the temperature rises on average by 160°C. The required fire resistance limits of PTR building structures are established according to R; RE; REJ, they are given in table. 6 (SNiP 21-01-97).
To ensure fire safety, the following condition must be met: the actual fire resistance limit of structures (Pf) (see Table 2) must be equal to or exceed the required fire resistance limit (Ptr) according to the standards: (Pf>Ptr).
A comparison of the fire resistance limits Ptr and Pf is made according to the form presented in table. 1. For load-bearing elements of a building, the fire resistance limit is determined according to R, according to RE - for elements of attic floors, according to REJ - for ceilings, including basement and attic floors, according to E - for external non-load-bearing walls.
The fire resistance limit when filling openings in fire barriers (doors, gates, glazed doors, valves, curtains, screens) occurs when integrity E is lost; thermal insulation capacity J; reaching the maximum density value heat flow W and/or smoke-tightness S. For example, smoke-tight doors with more than 25% glazing must have a fire resistance rating of EJWS60 for the first type of infill; EJSW30 - for the second type of filling the opening and EJSW15 - for the third type of filling the opening within fire limits.
The fire resistance limit according to W is characterized by achieving the maximum value of heat flux density at a standardized distance from an unheated surface building structure(see Technical regulations on fire safety requirements No. 123-FZ).
The fire hazard of building materials is assessed by a number of fire-technical characteristics: flammability, flammability, flame spread over the surface, smoke-generating ability and toxicity. For example, according to flammability, building materials are divided into:
G1-low flammable;
G2-moderately flammable;
G3-normally flammable;
G4-highly flammable.
They are similarly divided into building materials according to other fire hazard characteristics (see SNiP 21-01-97* “Fire hazard of buildings and structures”).
Table 3
| Room categories | Characteristics of substances and materials located in the room |
| A. Explosion and fire hazard | Combustible gases, flammable liquids with a flash point of no more than 28°C in such quantities that they can form vapor-gas mixtures, upon ignition of which an excess explosion pressure in the room exceeds 5 kPa. Substances and materials capable of exploding and burning when interacting with water, air oxygen or with each other in such quantities that the excess design explosion pressure in the room exceeds 5 kPa (0.05 kgf/cm2) |
| B. Explosion and fire hazard | Combustible dusts and fibers, flammable liquids with a flash point of more than 28°C. Flammable liquids in such quantities that they can form explosive dust-air or steam-air mixtures, the ignition of which develops an excess explosion pressure in the room exceeding 5 kPa (0.05 kgf/cm2) |
| B1-B4. Fire hazardous | Flammable and low-flammable liquids, solid flammable and low-flammable substances and materials (including dust and fibers), substances and materials that can only burn when interacting with water, air oxygen or with each other, provided that the rooms in which they are present in stock or in circulation, do not belong to categories A and B |
| G. | Non-flammable substances and materials in a hot state, the processing of which is accompanied by the release of radiant heat, sparks and flames. Flammable gases, liquids and solids that are burned or disposed of as fuel. |
| D. | Non-flammable substances and materials in a cold state. |
Table 4
Table 5
| Fire resistance level of the building | Structural fire hazard class of the building | Maximum permissible building height, m | Allowable floor area, fire compartment, m2 |
| I | CO CO Cl | 75 50 28 | 2500 2500 2200 |
| II | CO CO Cl | 28 28 15 | 1800 1800 1800 |
| III | CO Cl C2 | 5 5 2 | 100 800 1200 |
| IV | Not standardized | 5 | 500 |
| V | Not standardized | 5;3 | 500;800 |
Table6
Fires caused by humans have become quite common and widespread. Thousands of fires occur annually, causing a number of unpleasant consequences. Therefore, during the construction of structures great importance has a fire resistance rating for the building. Each constructed object is assigned a specific fire resistance number, according to the existing classification. Next, we will consider the classification in more detail and describe the parameters of each class.
What is the degree of fire resistance?
| Fire resistance level of the structure | Fire safety class of the structure | Maximum permissible height of the structure, cm | Allowable floor S, cm2 |
| I | Co Co Cl | 7500 5000 2800 | 250000 250000 220000 |
| II | Co Co Cl | 2800 2800 1500 | 180000 180000 180000 |
| III | Co Cl C2 | 500 500 200 | 10000 80000 120000 |
| IV | Without rationing | 500 | 50000 |
| V | Without rationing |
SNiP 31-01-03
This definition is understood as the ability of structures to restrain the expansion of the flammable area without the building losing its ability to further operate. The list of these properties consists of enclosing and load-bearing abilities.
If the structure loses bearing capacity- it will certainly collapse. It is by destruction that this definition is meant. As for the barrier ability, its loss is considered to be the level of heating of materials until cracks or holes form through which combustion products can spread into adjoining rooms or heating to the temperature at which the combustion process of the material begins.
The indicator of the maximum degree of fire resistance of structures is the time interval from the moment of fire formation to the appearance of signs of such losses (measured in hours). To test the performance of materials under fire conditions, a prototype is taken and placed in equipment for such experiments - a special furnace. In a kiln environment, the test item is subjected to high-temperature fire, which places stress on the material that is specific to the specific project.
The degree of fire resistance, when determining its limit, also depends on the ability to increase the temperature at individual points or the average value of the increase in temperature indicators over the surface, which is compared with the original one. The structural elements of the structure made of metal have the minimum resistance to fire, and the maximum resistance is reinforced concrete, in the manufacture of which cement with cement was used. high performance fire resistance. The maximum fire resistance level can reach 2.5 hours.
Also, when determining the ability of a structure to withstand fire, the limit of fire spread is taken into account. It is equivalent to the extent of damage in areas that were outside the combustion zone. This figure can be 0-40 cm.
We can safely say that the degree of fire resistance of structures directly depends on the ability of the materials used in its construction to withstand high temperatures, affecting the surface in a fire environment.
According to the degree of combustion, materials are divided into 3 groups:
- Fireproof (reinforced concrete structures, brick, stone elements).
- Refractory (materials from the combustible group, the fire resistance of which is increased by treatment with special means).
- Combustible (quickly ignites and burns well).
To classify materials, a special set of documents is used - SNIP.
How is it determined?
The degree of fire resistance is a representative of the most significant parameters of a structure, not inferior in importance to the design features in terms of fire safety and functional characteristics. But what should you pay attention to in order to determine it? extreme precision? To do this, you need to consider the following construction parameters:
- Number of storeys.
- Actual area of the structure.
- Nature of the building's purpose: industrial, residential, commercial, etc.
To determine the degree of fire resistance (I, II, etc.) it is necessary to determine solely on regulations and given in SNIP. Also for such purposes and the design of high-rise buildings, DBN 1.1-7-2002 is used, to determine the fire safety of multi-storey buildings, 4 DBN V.2.2-15-2005 are used, and to become familiar with the fire safety requirements for structures with big amount floors apply 9 DBN V.2.2-24:2009. Only the use of special documentation will allow you to obtain the most full information about the degrees of fire resistance of buildings with different design features.
