The fire hazard of building materials is characterized by the following properties:

1. combustibility;
2. Flammability;
3. The ability to spread flame over the surface;
4. Smoke generating ability;
5. Toxicity of combustion products.

By combustibility building materials are divided into combustible (G) and non-combustible (NG).

Building materials are classified as non-combustible with the following values ​​of combustibility parameters determined experimentally: temperature increase - no more than 50 degrees Celsius, sample weight loss - no more than 50 percent, duration of stable flame burning - no more than 10 seconds.

Building materials that do not meet at least one of the parameter values ​​specified in Part 4 of this Article are classified as combustible. Combustible building materials are divided into the following groups:

• Slightly combustible (G1), having a flue gas temperature of not more than 135 degrees Celsius, the degree of damage along the length of the test sample is not more than 65 percent, the degree of damage by weight of the test sample is not more than 20 percent, the duration of self-burning is 0 seconds;
• Moderately combustible (G2), having a flue gas temperature of not more than 235 degrees Celsius, the degree of damage along the length of the test sample is not more than 85 percent, the degree of damage by weight of the test sample is not more than 50 percent, the duration of independent combustion is not more than 30 seconds;
• Normally flammable (HC), having a flue gas temperature of not more than 450 degrees Celsius, the degree of damage along the length of the test sample is more than 85 percent, the degree of damage by weight of the test sample is not more than 50 percent, the duration of self-burning is not more than 300 seconds;
• Highly combustible (G4), having a flue gas temperature of more than 450 degrees Celsius, the degree of damage along the length of the test sample is more than 85 percent, the degree of damage by weight of the test sample is more than 50 percent, the duration of independent combustion is more than 300 seconds.

For materials belonging to the flammability groups G1-GZ, the formation of burning melt drops during testing is not allowed (for materials belonging to the flammability groups G1 and G2, the formation of melt drops is not allowed). For non-combustible building materials, other fire hazard indicators are not determined and not standardized.

By flammability combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

• Flammable (B1), having a critical surface heat flux density of more than 35 kilowatts per square meter;
• Moderately flammable (B2), having a critical surface heat flux density of at least 20, but not more than 35 kilowatts per square meter;
• Flammable (VZ), having a critical surface heat flux density of less than 20 kilowatts per square meter.

By flame propagation speed on the surface, combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

• Non-propagating (RP1), having a value of critical surface heat flux density of more than 11 kilowatts per square meter;
• Weakly propagating (RP2), having a value of critical surface heat flux density of at least 8, but not more than 11 kilowatts per square meter;
• Moderately spreading (RPZ), having a value of critical surface heat flux density of at least 5, but not more than 8 kilowatts per square meter;
• Strongly propagating (RP4), having a critical surface heat flux density of less than 5 kilowatts per square meter.

By smoke generating combustible building materials, depending on the value of the smoke generation coefficient, are divided into the following groups:

• With a low smoke generating capacity (D1), having a smoke generating coefficient of less than 50 square meters per kilogram;
• With a moderate smoke generating capacity (D2), having a smoke generating coefficient of at least 50, but not more than 500 square meters per kilogram;
• With a high smoke generating capacity (DZ), having a smoke generation coefficient of more than 500 square meters per kilogram.

By toxicity combustion products, combustible building materials are divided into the following groups in accordance with Table 2 of the Appendix to this Federal Law:

• Low-dangerous (T1);
• Moderately hazardous (T2);
• Highly hazardous (TK);
• Extremely dangerous (T4).

Depending on the fire hazard groups, building materials are divided into the following Fire hazard classes:

Fire hazard properties of building materials	Fire hazard class of building materials depending on groups
	KM0	KM1	KM2	KM3	KM4	KM5
combustibility	NG	G1	G1	G2	G2	G4
Flammability	—	IN 1	IN 1	IN 2	IN 2	AT 3
Smoke generating capacity	—	D1	D3+	D3	D3	D3
Toxicity of combustion products	—	T1	T2	T2	T3	T4
Flame spread over flooring surface	—	RP1	RP1	RP1	RP2	WP4

Flammability group- this is a classification characteristic of the ability of substances and materials to.

When determining the fire and explosion hazard of substances and materials (), there are :

• gases- these are substances whose saturated vapor pressure at a temperature of 25 ° C and a pressure of 101.3 kPa exceeds 101.3 kPa;
• liquids- these are substances whose saturated vapor pressure at a temperature of 25 ° C and a pressure of 101.3 kPa is less than 101.3 kPa. Liquids also include solid melting substances whose melting or dropping point is less than 50 °C.
• solids and materials- these are individual substances and their mixed compositions with a melting or dropping point of more than 50 ° C, as well as substances that do not have a melting point (for example, wood, fabrics, etc.).
• dust are dispersed solids and materials with a particle size of less than 850 microns.

One of the indicators of the fire and explosion hazard of substances and materials is combustibility group.

Substances and materials

According to GOST 12.1.044-89, in terms of flammability, substances and materials are divided into the following groups ( with the exception of building, textile and leather materials):

1. Non-combustible.
2. Slow-burning.
3. combustible.

non-combustible - These are substances and materials that are unable to burn in air. Non-combustible substances can be fire and explosion hazardous (for example, oxidizing agents or substances that release combustible products when interacting with water, atmospheric oxygen, or with each other).

slow-burning - these are substances and materials that can burn in the air when exposed to an ignition source, but are unable to burn on their own after its removal.

combustible - these are substances and materials capable of spontaneous combustion, as well as ignite when exposed to an ignition source and burn independently after its removal.

The essence of the experimental method for determining combustibility is to create temperature conditions conducive to combustion and to evaluate the behavior of the studied substances and materials under these conditions.

Solid (including dust)

The material is classified as non-combustible if the following conditions are met:

• the arithmetic mean temperature change in the furnace, on the surface and inside the sample does not exceed 50 °C;
• the arithmetic mean value of weight loss for five samples does not exceed 50% of their mean value of the initial weight after conditioning;
• the arithmetic mean value of the duration of stable combustion of five samples does not exceed 10 s. The test results of five samples in which the duration of stable combustion is less than 10 s are taken equal to zero.

According to the value of the maximum temperature increment (Δt max) and mass loss (Δm), materials are classified:

• slow-burning: Δt max< 60 °С и Δm < 60%;
• combustible: Δt max ≥ 60 °С or Δm ≥ 60%.

Combustible materials are divided depending on the time (τ) to reach (t max) into:

• flame retardant: τ > 4 min;
• medium flammability: 0.5 ≤ τ ≤ 4 min;
• flammable: τ< 0,5 мин.

gases

In the presence of concentration limits of flame propagation, the gas is classified as fuel ; in the absence of concentration limits for the spread of flame and the presence of a self-ignition temperature, the gas is classified as slow-burning ; in the absence of concentration limits for flame propagation and self-ignition temperature, the gas is classified as non-combustible .

Liquids

In the presence of an ignition temperature, the liquid is classified as fuel ; in the absence of an ignition temperature and the presence of a self-ignition temperature, the liquid is classified as slow-burning . In the absence of flash, ignition, self-ignition temperatures, temperature and concentration limits of flame propagation, the liquid is classified as non-combustible . Combustible liquids with a flash point of not more than 61 ° C in a closed crucible or 66 ° C in an open crucible, phlegmatized mixtures that do not have a flash in a closed crucible are classified as flammable . especially dangerous are called flammable liquids with a flash point of not more than 28 ° C.

Classification of building materials

Determination of the combustibility group of a building material

The fire hazard of building, textile and leather materials is characterized by the following properties:

1. The ability to spread flame over a surface.
2. smoke generating ability.
3. Toxicity of combustion products.

Building materials, depending on the values ​​​​of combustibility parameters, are divided into groups into non-combustible and combustible (for floor carpets, the flammability group is not determined).

NG (non-flammable)

Non-combustible building materials according to the test results according to methods I and IV () are divided into 2 groups.

Building materials are classified as non-combustible group I

• temperature increase in the furnace is not more than 30 °C;
• the duration of stable flame burning is 0 s;
• calorific value not more than 2.0 MJ/kg.

Building materials are classified as non-combustible group II with the following arithmetic mean values ​​of combustibility parameters according to methods I and IV (GOST R 57270-2016):

• temperature increase in the furnace is not more than 50 °C;
• weight loss of samples no more than 50%;
• the duration of stable flame burning is not more than 20 s;
• calorific value not more than 3.0 MJ/kg.

It is allowed to refer without testing to non-combustible group I the following building materials without painting their outer surface or with painting the outer surface with compositions without the use of polymeric and (or) organic components:

• concretes, mortars, plasters, adhesives and fillers, clay, ceramic, porcelain stoneware and silicate products (bricks, stones, blocks, slabs, panels, etc.), fiber cement products (sheets, panels, slabs, pipes, etc. .) except in all cases for materials made using polymeric and (or) organic binder aggregates and fibers;
• inorganic glass products;
• products from alloys of steel, copper and aluminum.

Building materials that do not meet at least one of the above indicated values ​​​​of the parameters I and II of the group of incombustibility belong to the group of combustible and are subject to testing according to methods II and III (GOST R 57270-2016). For non-combustible building materials, other fire hazard indicators are not determined and not standardized.

Combustible building materials, depending on the values ​​of the combustibility parameters determined by method II, are divided into four combustibility groups (G1, G2, G3, G4) according to the table. Materials should be assigned to a certain combustibility group, provided that all the arithmetic mean values ​​of the parameters established by the table for this group correspond.

G1 (low combustible)

Slightly combustible - these are materials with a flue gas temperature of not more than 135 ° C, the degree of damage along the length of the test sample is not more than 65%, the degree of damage by weight of the test sample is not more than 20%, the duration of self-burning is 0 seconds.

G2 (moderately flammable)

Moderately combustible - these are materials with a flue gas temperature of not more than 235 ° C, the degree of damage along the length of the test sample is not more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of self-burning is not more than 30 seconds.

G3 (normally combustible)

Normal flammable - these are materials with a flue gas temperature of not more than 450 ° C, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of self-burning is not more than 300 seconds.

G4 (highly flammable)

highly flammable - these are materials with a flue gas temperature of more than 450 ° C, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is more than 50%, the duration of self-burning is more than 300 seconds.

table

Combustibility group of materials	Flammability parameters
	Flue gas temperature T, °C	Degree of damage along the length S L, %	Degree of damage by weight S m, %	Duration of self-burning t c.g, s
G1	Up to 135 inclusive	Up to 65 inclusive	up to 20	0
G2	Up to 235 inclusive	Up to 85 inclusive	Up to 50	Up to 30 inclusive
G3	Up to 450 inclusive	Over 85	Up to 50	Up to 300 inclusive
G4	Over 450	Over 85	Over 50	Over 300
Note. For materials belonging to the flammability groups G1-G3, the formation of burning melt drops and (or) burning fragments during testing is not allowed. For materials belonging to the combustibility groups G1-G2, the formation of a melt and (or) melt drops during testing is not allowed.

Video, what is a flammability group

Sources: ; Baratov A.N. Combustion - Fire - Explosion - Safety. -M.: 2003; GOST 12.1.044-89 (ISO 4589-84) Occupational safety standards system. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination; GOST R 57270-2016 Building materials. Test methods for combustibility.

In order to protect the life, health, property of citizens and legal entities, state and municipal property, the legislation of the Russian Federation provides for requirements for various types of products.

Such requirements are contained in the technical regulations.

Federal Law No. 123-FZ of July 22, 2008 "Technical Regulations on Fire Safety Requirements" (hereinafter referred to as the Technical Regulations) establishes requirements for building materials.

Article 13 of the Technical Regulations establishes the classification of building materials according to fire hazard.

This classification is based on the properties of materials to form fire hazards.

The fire hazard of building materials is characterized by the following properties:

1) combustibility;

2) flammability;

3) the ability to spread the flame over the surface;

4) smoke generating capacity;

5) toxicity of combustion products.

By combustibility, building materials are divided into combustible (G) and non-combustible (NG).

Building materials are classified as non-combustible with the following values ​​of combustibility parameters determined experimentally: temperature increase - no more than 50ºС, sample weight loss - no more than 50%, duration of stable flame burning - no more than 10 seconds. Building materials that do not satisfy at least one of the specified parameter values ​​are classified as combustible.

Combustible building materials are divided into the following groups:

Slightly combustible (G1), having a flue gas temperature of not more than 135 ºС, the degree of damage along the length of the test sample is not more than 65%, the degree of damage by weight of the test sample is not more than 20%, the duration of self-burning is 0 seconds;

Moderately combustible (G2), having a flue gas temperature of not more than 235 ºС, the degree of damage along the length of the test sample is not more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of independent combustion is not more than 30 seconds;

Normally combustible (G3), having a flue gas temperature of not more than 450 C, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of independent combustion is not more than 300 seconds;

Highly combustible (G4), having a flue gas temperature of more than 450 ºС, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is more than 50%, the duration of self-burning is more than 300 seconds.

At the same time, for materials belonging to the flammability groups G1 - G3, the formation of burning melt drops during testing is not allowed (for materials belonging to the flammability groups G1 and G2, the formation of melt drops is not allowed). For non-combustible building materials, other fire hazard indicators are not determined and not standardized.

7. In terms of flammability, combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

Flame-retardant (B1), having a critical surface heat flux density of more than 35 kW / m 2;

Moderately flammable (B2), having a critical surface heat flux density of at least 20, but not more than 35 kW / m 2;

Highly flammable (B3), having a critical surface heat flux density of less than 20 kW / m 2.

8. According to the speed of flame propagation over the surface, combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

Non-propagating (RP1), having a value of critical surface heat flux density of more than 11 kW / m 2;

Weakly propagating (RP2), having a value of critical surface heat flux density of at least 8, but not more than 11 kW / m 2;

Moderately spreading (RP3), having a value of critical surface heat flux density of at least 5, but not more than 8 kW / m 2;

Strongly spreading (RP4), having a critical surface heat flux density of less than 5 kW / m 2.

9. According to the smoke-generating ability, combustible building materials, depending on the value of the smoke generation coefficient, are divided into the following groups:

With a low smoke generating capacity (D1), having a smoke generating coefficient of less than 50 m 2 /kg;

With moderate smoke-generating ability (D2), having a smoke-generating coefficient of at least 50, but not more than 500 m 2 /kg;

With a high smoke generating capacity (D3), having a smoke generating coefficient of more than 500 m 2 /kg.

10. According to the toxicity of combustion products, combustible building materials are divided into the following groups:

Low-dangerous (T1);

Moderately hazardous (T2);

Highly dangerous (T3);

Extremely dangerous (T4).

The purpose of determining the fire hazard groups of materials is to assess the possibility of their use in specific buildings and structures.

Based on the fire hazard groups of materials, fire hazard classes are determined in accordance with Part 11 of Article 3 and Appendix 3 of the Technical Regulations.

Fire hazard classes of building materials

Fire hazard properties of building materials	Fire hazard class of building materials depending on groups
	KM0	KM1	KM2	KM3	KM4	KM5
combustibility	NG	G1	G1	G2	G3	G4
Flammability		IN 1	IN 2	IN 2	IN 2	AT 3
Smoke generating capacity		D 2	D 2	D3	D3	D3
Toxicity		T2	T2	T2	T3	T4
Flame spread		RP1	RP1	RP2	RP2	WP4

And, in turn, on the basis of hazard classes, the scope of application of decorative and finishing, facing materials and floor coverings on escape routes and in halls in buildings of various functional purposes, number of storeys and capacity is determined, in accordance with Part 6 of Article 134 and Annexes 28, 29 of the Technical Regulations.

Scope of decorative and finishing, facing

materials and floor coverings on escape routes

	Floors and building height	Fire hazard class of material, not more than specified
		for walls and ceilings		for flooring
			Common corridors, halls, foyers	Vestibules, stairwells, lift lobbies	Common corridors, halls, foyers
F1.2; F1.3; F2.3; F2.4; F3.1; F3.2; F3.6; F4.2; F4.3; F4.4; F5.1; F5.2; F5.3	no more than 9 floors or no more than 28 meters	KM2	KM3	KM3	KM4
	more than 9 but not more than 17 floors or more than 28 but not more than 50 meters	KM1	KM2	KM2	KM3
	more than 17 floors or more than 50 meters	KM0	KM1	KM1	KM2
	regardless of number of storeys and height	KM0	KM1	KM1	KM2

Scope of decorative and finishing, facing materials and floor coverings in halls, with the exception of floor coverings of sports arenas of sports facilities and floors of dance halls

Class (subclass) of the functional fire hazard of the building	Hall capacity, people	Material class, not more than specified
		for walls and ceilings	for floor coverings
F1.2; F2.3; F2.4; F3.1; F3.2; F3.6; F4.2; F4.3; F4.4; F5.1	over 800	KM0	KM2
	more than 300 but not more than 800	KM1	KM2
	more than 50 but not more than 300	KM2	KM3
	no more than 50	KM3	KM4
F1.1; F2.1; F2.2; F3.3; F3.4; F3.5; F4.1	over 300	KM0	KM2
	more than 15 but not more than 300	KM1	KM2
	no more than 15	KM3	KM4

To determine the fire hazard groups of building materials, tests are carried out according to the methods contained in the national standards included in the List approved by Order of the Government of the Russian Federation dated March 10, 2009 No. 304-r:

Tests for incombustibility are carried out according to GOST 30244-94. Construction materials. Flammability test methods (MethodI);

Tests to determine the flammability groups are carried out according to GOST 30244-94. Construction materials. Flammability test methods (MethodII);

Tests to determine flammability groups are carried out in accordance with GOST 30402-96 Building materials. Flammability test method;

Tests to determine the flame propagation groups over the surface are carried out in accordance with GOST R 51032-97 Building materials. Flame propagation test method;

Tests to determine the smoke-generating ability groups are carried out in accordance with GOST 12.1.044-89 (ISO 4589-84) Interstate standard. System of labor safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination (clause 4.18);

Tests to determine the toxicity groups of combustion products are carried out in accordance with GOST 12.1.044-89 (ISO 4589-84) Interstate standard. System of labor safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination (clause 4.20).

As part of the Center for Expertise, Research and Testing in Construction, the Fire Testing Laboratory and the Fire Control Department operate. At the same time, the Fire Control Department is entrusted with the functions of an inspection body for sampling and evaluating test results. The fire test laboratory performs the functions of testing product samples, while the test results are sent by means of sample encryption to the Fire Control Department for assessment and assignment of specific fire hazard groups.

The fire test laboratory of the State Budgetary Institution "Center for Expertise, Research and Testing in Construction" conducts daily tests of building materials.

For 9 months of 2017, 285 tests were carried out, according to the results of which protocols were drawn up containing indicators of materials used directly at new construction sites in Moscow.

The main types of products tested are: facing boards for facade systems (121 tests), paints (28 tests), insulation (74 tests), linoleums (15 tests), other types of products (59 tests) [lacquer, floor coverings, vapor barrier, wallpaper].

It should be noted that a significant number of tests reveal the discrepancy between the materials used and the requirements imposed on them.

So 73% of the tested fiber cement boards for facades are not non-combustible (NG). At the same time, 100% of fiber cement boards tested for flammability correspond to the flammability group G1.

Also, many linoleum samples do not pass tests for the declared flammability groups (B). 83% of linoleum samples correspond to the B3 flammability group, while products with higher rates (B1 or B2) should be used.

The paints used at construction sites also often do not correspond to the declared indicators. 100% of the tested paints do not meet the incombustibility index (NG). In terms of combustibility (G) - 85% of the tested paint samples correspond to the combustibility group G1 and 15% - to the group G2. In terms of flammability (B), 22% of the tested paint samples do not meet the declared values. 78% of them correspond to the B1 group, the rest to the B2 and B3 groups.

100% of the tested samples of mineral wool insulation correspond to the incombustibility index (NG).

Based on the laboratory protocols, the inspection body of the State Budgetary Institution "CEIIS" issues conclusions containing the fire hazard groups of materials, as well as conclusions on the compliance or non-compliance of the materials used with the requirements of design and regulatory documentation.

Tests to determine the fire hazard indicators of building materials used directly at construction sites is a necessary input control aimed at preventing fires and reducing damage from fires at new construction sites.

Literature:

1. Federal Law No. 184-FZ of December 27, 2002 "On Technical Regulation".

2. Federal Law of July 22, 2008 No. 123-FZ "Technical Regulations on Fire Safety Requirements".

3. GOST 30244-94. Construction materials. Test methods for combustibility.

4. GOST 30402-96 Construction materials. Flammability test method.

5. GOST R 51032-97 Construction materials. Flame propagation test method.

6. GOST 12.1.044-89 (ISO 4589-84) Interstate standard. System of labor safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination.

The text of the article was:

Leading engineer of the LOI GBU "CEIIS" S.V. Rusyaev

Checked:

Head of the LOI GBU "CEIIS" N.V. Afanasiev

Construction. This includes housing stock, public buildings, administrative facilities, shopping centers, etc. Both at the stage of design, construction, and for capital, ongoing repairs, it is necessary to create maximum measures to create compliance with fire safety. This applies to systems that provide the public sector: electricity, heating, all kinds of heating, the use of electrical appliances.

It is worth noting that building materials also come under close control and require attention in terms of their quality, reliability and safety. Often it is the materials used that cause a fire, because their use was incorrect and ill-conceived. Therefore, a flammability class is used for them.

General classification

In order to proceed directly to the breakdown of certain materials into classes, it is necessary to understand what is made up of and on what their classification according to the level of fire hazard is based. The flammability class depends on the properties of the building material used and on its ability to cause a fire during operation. Therefore, to determine the safety and the stage of danger, it is necessary to appeal to a number of properties. These include combustibility and flammability, as well as the rate of spread of fire over the surface. Important factors are the toxicity released during combustion and the level of smoke during combustion. According to regulatory documents, combustibility is divided into two types: combustible (G) and non-combustible (NG).

Non-combustible materials

This category does not become a complete guarantee of safety, because the combustibility group does not imply a complete absence of changes in the characteristics of the material during combustion. This means that when exposed to fire, it is less active and remains resistant to high temperatures longer.

There is a certain method for determining incombustibility. If during combustion the temperature increase is at least 50 ° C, and the total mass loss does not exceed 50%, then such a material can be classified as non-combustible. In this case, the stability of continuous burning should not exceed 0 seconds.

How does the composition of the material affect the degree of flammability

Non-combustible materials can be safely attributed to those that are made from mineral substances and become the basis of the entire product. These are brick, glass, concrete, ceramic products, natural stone, asbestos cement and other building materials that have a similar composition. But in the production, other substances are also used as additives, the combustibility group of which is different. These are organic or polymeric compounds. Thus, non-combustible material already becomes vulnerable in the combustion process, which means that confidence in its non-combustibility is significantly reduced. Depending on the proportions that make up the production for the preparation of a particular product, the material can move from the category of non-combustible to the group of slow-burning or combustible.

Types of flammability classes

Regulatory documents impose requirements on the need to ensure fire safety, and GOST 30244-94 establishes a flammability class and methods for testing building materials for flammability. Depending on the indicators and the behavior of the material when exposed to fire, 4 classes are distinguished.

Slightly combustible

A group that includes materials during combustion of which the flue gas temperature does not exceed 135 ° C. Combustibility G1 must have a degree of damage to the material along the entire length of the sample of not more than 65%, and a degree of destruction of not more than 20%. In addition, self-burning should be 0 seconds.

Moderately combustible

A group that includes materials, during combustion of which the flue gas temperature does not exceed 235 ° C. Combustibility class 2 has a degree of damage to the material along the entire length of the sample not more than 85%, the degree of destruction is not more than 50%, and self-burning should not exceed 30 seconds .

Normal flammable

A group that includes materials during combustion of which the temperature of the flue gases does not exceed 450 ° C. Combustibility G3 must have a degree of damage to the material along the entire length of the sample of no more than 85%, a degree of destruction of no more than 50%, and spontaneous combustion should not exceed 300 seconds .

highly flammable

A group that includes materials, during the combustion of which the temperature of the flue gases begins to exceed the threshold of 450 ° C. The flammability class G4 has a degree of damage to the material along the entire length of the sample of more than 85%, a degree of destruction of more than 50%, and self-burning exceeds 300 seconds.

Additional requirements are imposed on combustibility materials G1, G2. When burning, they should not form drops of melt. An example is linoleum. The flammability class of this floor covering cannot be 1 or 2 due to the fact that it melts strongly during combustion.

Material Safety Parameters

In addition to the flammability class, additional parameters are used in the aggregate to classify the safety level of building materials, which are determined through tests. This includes toxicity, which has 4 subsections:

• T1 - low degree of danger.
• T2 - moderate degree.
• T3 - increased indicators of danger.
• T4 - super-dangerous degree.

The smoke-generating factor is also taken into account, which contains 3 classes in the regulatory documents:

• D1 - low ability.
• D2 - average ability.
• D3 - high ability.

Flammability is important

• B1 - flame retardant.
• B2 - moderately flammable.
• B3 - flammable.

And the final criterion that makes up the safe use of products is their ability to spread flame over the combustion surface:

• RP-1 - non-propagating.
• RP-2 - weakly propagating.
• RP-3 - moderately spreading.
• RP-4 - strongly propagating.

The choice of building materials

The combustibility class and additional criteria for assessing safe materials are a significant indicator when choosing. The structure, regardless of the scope, place of use, must be safe for humans and, moreover, eliminate the risk of harm to health. First of all, it is necessary to competently approach the appointment of building materials in a specific area of ​​\u200b\u200bwork. In construction and repair, constructive, finishing, roofing, insulating materials are used, which means that each of them has its place of application. Improper use may cause fire.

When purchasing building materials, it is imperative to study the label with characterizing indicators. Manufacturers that comply with the technology indicate information containing codes that reflect the degree of fire safety. In addition to marking, the seller, upon request, must present a certificate of conformity for the goods. It also reflects indicators relating to safe use. Underground production or manufacturing in violation of technology significantly reduces the quality, the level of resistance to the effects of certain loads, and also absolutely does not comply with fire safety requirements.

Separately, it is worth noting the objects of social infrastructure, where different structures, shapes, composition of the product are used for decoration. Special control is exercised over educational organizations, preschool institutions, medical buildings. Conditionality takes place, since a large concentration of children in one place should completely exclude any risk for them. In this regard, the relevant regulatory authorities conduct ongoing inspections of these facilities. As a result, designers and developers are guided by the standards, taking into account the object of the proposed work, taking into account, among other things, the combustibility of materials.

Ensuring fire safety is one of the key tasks in the construction and operation of modern skyscrapers, large business centers and shopping and entertainment complexes. The specificity of such buildings - a large length of evacuation routes - dictates increased requirements for fire safety of the building structures and materials used. And only when these requirements are met along with the solution of other technical and economic problems, the building is considered to be designed correctly.

According to the Federal Law of the Russian Federation of July 22, 2008 No. 123-FZ "Technical Regulations on Fire Safety Requirements", the choice of building materials directly depends on the functional purpose of the building or premises.

Classification of building materials often carried out based on the scope of the product. According to this criterion, it is divided into constructive, insulating and finishing, as well as constructive-insulating and constructive-finishing solutions.

From point of view fire safety an optimal classification is proposed in Article 13 of the "Technical Regulations", which divides building materials into two types: combustible and non-combustible. In turn, combustible materials are divided into 4 groups - low combustible (G1), moderately combustible (G2), normally combustible (G3) and, finally, highly combustible (G4).

In addition, they are evaluated according to criteria such as flammability, ability to spread flame on the surface smoke generating capacity and toxicity. The combination of these indicators allows you to assign a fire hazard class to a specific material: from KM0 - for non-combustible materials to KM1-KM5 - for combustible.

Natural properties of materials

The key factor determining the fire hazard of building materials is raw material from which they are made. In this respect, they can be divided into three large groups: inorganic, organic and mixed. Let's take a closer look at the properties of each of them. Let's start with mineral materials, which belong to the group of inorganic materials and, along with metal structures, serve to create a rigid frame - the basis of modern buildings.

Most common mineral building materials- this is a natural stone, concrete, brick, ceramics, asbestos cement, glass, etc. They are classified as non-combustible (NG), but even with a small addition of polymeric or organic substances - no more than 5-10% by weight - their properties change. The fire danger increases, and from NG they move into the category of slow-burning.

In recent years, products based on polymers, which belongs to inorganic materials and is combustible. In this case, the affiliation of a particular material to the combustibility group depends on the volume and chemical structure of the polymer. There are two main types of polymer compounds. These are thermoplastics that form a coke layer when heated, which consists of non-combustible substances and protects the material from high temperatures, preventing combustion. Another type is thermoplastics (melted without creating a heat-shielding layer).

Regardless of the type, polymer building materials cannot be classified as non-combustible, but it is possible to reduce their fire hazard. To do this, fire retardants are used - various substances that help to increase fire resistance. Flame retardants for polymeric materials can be divided into three large groups.

The first includes substances that chemical interaction with polymer. These flame retardants are mainly used for thermosets, without deterioration of their physical and chemical properties. The second group of flame retardants - intumescent additives- under the influence of a flame, it forms a foamed cellular coke layer on the surface of the material, which prevents combustion. And finally, the third group is substances that mechanically mixed with polymer. They are used to reduce the flammability of both thermoplastics and thermoplastics and elastomers.

Of all organic materials, wood and its products are most widely used in the construction of modern buildings - particle boards(chipboard), fibreboard(Fibreboard), plywood etc. All organic materials belong to the combustible group, and their fire hazard increases with the addition of various polymers. For example, paints and varnishes not only increase flammability, but also contribute to a faster spread of flame over the surface, increase smoke generation and toxicity. In this case, other toxic substances are added to CO (carbon monoxide), the main combustion product of organic materials.

To reduce the fire hazard of organic building materials, as in the case of polymeric substances, they are treated flame retardants. When applied to a surface, flame retardants can foam or release non-flammable gas when exposed to high temperatures. In both cases, they impede the access of oxygen, preventing the ignition of wood and the spread of flame. Effective flame retardants are substances containing diammonium phosphate, as well as a mixture of sodium phosphate with ammonium sulfate.

Concerning mixed materials, they are composed of organic and inorganic raw materials. As a rule, construction products of this type are not allocated to a separate category, but belong to one of the previous groups, depending on which raw materials prevail. For example, fibrolite, consisting of wood fibers and cement, is considered organic, and bitumen- inorganic. Most often, the mixed type belongs to the group of combustible products.

Increased requirements for fire safety of large shopping and entertainment and office centers, as well as high-rise buildings dictate the need to develop a set of fire prevention measures. One of the most important is the predominant use non-combustible and low combustible building materials. In particular, this applies to the load-bearing and enclosing structures of the building, roofing, as well as materials for finishing escape routes.

According to the classification of NPB 244-97, finishing, facing, roofing, waterproofing and heat-insulating materials, as well as floor coverings are subject to mandatory certification in the field of fire safety. Consider these categories for fire hazard.

Finishing and facing materials

There are many finishing and facing materials, among which are polystyrene tiles, PVC and chipboard panels, wallpaper, films, ceramic tiles, fiberglass, etc. Most products of this type are combustible. In rooms with a mass gathering of people, as well as in buildings where evacuation is difficult due to the large area and number of storeys, finishing materials can create an additional threat to the life and health of people, causing smoke, releasing toxic combustion products and contributing to the rapid spread of flames. Therefore, it is necessary to choose materials not lower than class KM2.

Depending on the surface on which they are applied, finishing materials may have different properties. For example, in combination with combustible substances, ordinary wallpaper can manifest itself as flammable, and applied to a non-combustible base - as low combustible. Therefore, when choosing finishing and facing materials, one should be guided not only by data on their fire hazard, but also by the properties of the bases.

For decoration of premises with a large crowd of people and evacuation routes, the use of organic products is unacceptable, in particular, MDF panels, which most often belong to the G3 and G4 groups. For finishing walls and ceilings in trading floors, materials with a higher fire hazard than class KM2 cannot be used.

Paper based wallpaper are not included in the list of products subject to mandatory certification, and they can be used as a finishing material for rooms with increased fire safety requirements, given that the base will be non-combustible.

As a replacement for MDF panels use drywall with an external covering from a decorative film. Thanks to plaster base drywall belongs to non-combustible materials, and a decorative film based on polymers transfers it to the G1 group, which allows it to be used for interior decoration of almost any functional purpose, including lobbies. Today, drywall is widely used for the construction of partitions - independent building structures. This must be taken into account when determining their fire hazard class.

Floor coverings

TO combustibility of floor coverings less stringent requirements are imposed than for finishing and facing materials. The reason is that during a fire, the floor is in the zone of the lowest temperature compared to the walls and ceiling. At the same time, for materials that serve as flooring, an important role is played by such an indicator as flame spread over the surface(RP).

Due to the ease of installation and high performance, they are widely used as floor coverings in corridors, lobbies, halls and foyers of buildings. linoleums- various types of rolled polymer coatings. Almost all materials of this type belong to the group of highly combustible (G4) and have a high coefficient of smoke formation. Already at a temperature of 300 ° C, they support combustion, and when heated above 450–600 ° C, they ignite. In addition, the combustion products of linoleums include toxic substances - carbon dioxide, CO and hydrogen chloride.

Therefore, they cannot be used as flooring for corridors and halls, where, according to the requirements, materials of at least KM3 must be used, not to mention lobbies and stairwells, for which more stringent requirements apply. The same can be said about the laminate, which consists of organic and polymeric materials and, regardless of type, is highly combustible - unsuitable for escape routes.

The most favorable, in terms of fire safety, are ceramic tile and porcelain stoneware. They belong to the KM0 group and are not included in the list of materials subject to certification in the field of fire safety. Such products are suitable for premises of any functional purpose. In addition, semi-rigid tiles made of polyvinyl chloride with a large amount of mineral filler (KM1 group) can be used as flooring in corridors and halls.

Roofing and waterproofing materials

Usually fire hazard of roofing materials indicated in the certificates as a flammability group. Roofs made of metal and clay are the least dangerous, and materials based on bitumen, rubber, rubber-bitumen products and thermoplastic polymers are the most dangerous. Although it is they who give roofing materials high performance characteristics - water and vapor impermeability, frost resistance, elasticity, resistance to negative atmospheric influences and cracking.

One of the most fire hazardous are roofing and waterproofing materials, which include bitumen. They spontaneously ignite already at a temperature of 230–300°C. In addition, bitumen has a high smoke generating capacity and burning rate.

Bitumens are widely used in the production of rolled (roofing material, glassine, glass roofing material, isol, hydroisol, foilizol) and mastic roofing and waterproofing materials. Almost all bitumen-based roofing materials belong to the G4 group. This imposes restrictions on their use in buildings with increased fire safety requirements. Yes, they must fit non-combustible base. In addition, over the top gravel backfill, as well as fire cuts are arranged, dividing the roof of the building into separate segments. This is necessary in order to localize the fire and prevent the spread of fire.

Today, dozens of types of waterproofing materials are on the market - polyethylene, polypropylene, polyvinyl chloride, polyamide, thiokol and other membranes. Regardless of the type, they all belong to the combustible group. The most favorable, in terms of fire safety, are waterproofing membranes related to the flammability group G2. As a rule, these are materials based on polyvinyl chloride with the addition of flame retardants.

Thermal insulation materials

Thermal insulation materials, subject to certification in the field of fire safety, can be divided into five groups. The first one is polystyrene foam. Due to their relatively low cost, they are widely used in modern construction. Along with good heat-insulating properties, this product has a number of serious drawbacks, including fragility, insufficient moisture resistance and vapor permeability, low resistance to ultraviolet rays and hydrocarbon liquids, and most importantly, high flammability and release of toxic substances during combustion.

One of the varieties of polystyrene foam is extruded polystyrene foam. It has a more ordered structure of small closed pores. This production technology increases the moisture resistance of the material, but does not reduce its fire hazard, which remains just as high. The ignition of polystyrene foam occurs at temperatures from 220°C to 380°C, and self-ignition corresponds to a temperature of 460–480°C. When burned, expanded polystyrenes emit a large amount of heat, as well as toxic products. Regardless of the type, all materials in this category belong to the G4 flammability group.

As a thermal insulation in the composition of plaster facade systems, expanded polystyrene is recommended to be installed with a mandatory device fire cuts from stone wool - non-combustible material. Due to the high fire hazard, the use of materials of this group is unacceptable in ventilated facade systems, as they can significantly increase the speed of flame propagation along the facade of the building. When using combined roofing, expanded polystyrene is laid on a non-combustible stone wool base.

The next type of thermal insulation material - polyurethane foam- is an infusible thermosetting plastic with a cellular structure, the voids and pores of which are filled with a gas with low thermal conductivity. Due to the low ignition temperature (from 325 ° C), strong smoke-generating ability, as well as the high toxicity of combustion products, which include hydrogen cyanide (hydrocyanic acid), polyurethane foam has an increased fire hazard. In the production of polyurethane foam, flame retardants are actively used, which can reduce flammability, but at the same time increase the toxicity of combustion products. In general, the use of polyurethane foam in buildings with high fire safety requirements is severely limited. If necessary, it can be replaced with a two-component material - polyisocyanurate foam, which has a lower flammability and combustibility.

Resole foams, made from resole phenol-formaldehyde resins, belong to the group of slow-burning. In the form of medium-density slabs, they are used for thermal insulation of external fences, foundations and partitions at a surface temperature not exceeding 130°C. When exposed to flame, resole foams char, retaining their overall shape, and have a low smoke-generating ability compared to polystyrene foam. One of the main disadvantages of this category of materials is that during destruction they release a set of highly toxic compounds, which, in addition to carbon monoxide, includes formaldehyde, phenol, ammonia and other substances that pose a direct threat to human life and health.

Another type of thermal insulation - glass wool, for the production of which the same materials are used as in the manufacture of glass, as well as waste from the glass industry. Glass wool has good thermal performance, and its melting point is about 500°C. However, due to some features, thermal insulation with a density of less than 40 kg / m³ belongs to the NG group.

stone wool- one of the most fireproof heat-insulating materials

The list of thermal insulation materials includes stone wool, which consists of fibers obtained from their rock of the basalt group. Stone wool has high heat and sound insulation characteristics, resistance to loads and various types of impact and durability. The materials of this group do not emit harmful substances and do not have a negative impact on the environment. Stone wool is the most reliable material in terms of fire safety: it is non-combustible and has a fire hazard class of KM0. Stone wool fibers are able to withstand temperatures up to 1000°C, thanks to which the material effectively prevents the spread of flames. Thermal insulation made of stone wool can be used without limitation in the number of storeys of the building.

The assessment of the fire hazard of thermal insulation was carried out within the framework of specialized seminars organized by VNIIPO Ministry of Emergency Situations. They were accompanied by full-scale fire tests, which involved common types of heat-insulating materials - expanded polystyrene, polyurethane foam, resole foam and stone wool. Under the influence of an open flame of the burner, the polystyrene foam melted with the formation of burning drops during the first minute of the experiment, the polyurethane foam burned out within 10 minutes. Within 30 minutes of the test, the resole foam was charred, and the stone wool did not change its original shape, proving that it belongs to non-combustible materials. The second part of the tests - imitation of the ignition of a roof with a heat-insulating layer - showed that the burning melt of expanded polystyrene, penetrating into the interior, contributes to the spread of fire and the emergence of new sources of ignition. Thus, according to the test results, conclusions were drawn about the high fire hazard of the most commonly used heat-insulating materials.

Summing up, it is necessary to reiterate the importance effective fire fighting measures during the design and construction of buildings. One of the central places is occupied by a fire hazard assessment and a competent choice of building materials, based on current norms and standards and taking into account the functional purpose and individual characteristics of the building. The use of modern materials allows for complete compliance with fire safety requirements, guaranteeing the safety of life and health of people who will be in the building after construction is completed.