Which flammability group is better g1 or g2. Non-combustible building materials. Fire hazard class of building structures

GOST 30244-94 establishes test methods building materials for flammability and their classification according to flammability.

The standard does not apply to varnishes, paints, and other building materials in the form of solutions, powders and granules.

The standard uses the following terms and definitions:

Sustained flaming combustion - continuous flaming combustion of materials for at least 5 s.

Exposed surface - the surface of the sample that is exposed to heat and/or open flame during a flammability test.

Building materials, depending on the values ​​of flammability parameters determined by method I (intended to classify building materials as non-combustible or combustible), are divided into non-combustible and combustible.

Building materials are classified as non-combustible with the following values ​​of flammability parameters:

temperature increase in the furnace is no more than 50°C;

sample weight loss no more than 50%;

Duration of stable flame combustion is no more than 10 s.

Construction materials that do not satisfy at least one of the specified parameter values ​​are classified as flammable.

Combustible building materials, depending on the values ​​of flammability parameters determined by method II (intended for testing combustible building materials in order to determine their flammability groups, are divided into four flammability groups: G1, G2, G3, G4. Materials should be assigned to a certain flammability group when provided that all parameter values ​​set for this group correspond.

Table 3.1

Note. Flammability groups G1 and G2 are equated to the group of low-combustible building materials according to the classification adopted in GOST 12.1.044-89 and SNiP 2.01.02-85*.

Date of publication: 2014-10-30; Read: 1336 | Page copyright infringement

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13 Federal Law dated July 22, 2008 No. 123-FZ

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

1. flammability;
2. flammability;
3. ability to spread flame over a surface;
4. smoke generating ability;
5. toxicity of combustion products.

Based on flammability, building materials are divided into combustible (G) and non-combustible (NG).

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

Construction materials that do not satisfy at least one of the parameter values ​​specified in Part 4 of this article are classified as flammable. Combustible building materials are divided into the following groups:

1) low-flammable (G1), having a temperature flue gases 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 independent combustion is 0 seconds;

2) moderately flammable (G2), having a flue gas temperature of no 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 along the mass of the test sample is not more than 50 percent, the duration of independent combustion is no more than 30 seconds;

3) normal-flammable (NG), having a flue gas temperature of no 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 along the mass of the test sample is not more than 50 percent, the duration of independent combustion is no more than 300 seconds;

4) highly flammable (G4), having a flue gas temperature of more than 450 degrees Celsius, a degree of damage along the length of the test sample of more than 85 percent, a degree of damage along the mass of the test sample of more than 50 percent, and a duration of independent combustion of more than 300 seconds.

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

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

1) hardly flammable (B1), having a critical surface heat flux density of more than 35 kilowatts per square meter;

2) moderately flammable (B2), having a critical surface heat flux density of at least 20, but not more than 35 kilowatts per square meter;

3) flammable (HF), having a critical surface heat flux density of less than 20 kilowatts per square meter.

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:

1) non-propagating (RP1), having a critical surface heat flux density of more than 11 kilowatts per square meter;
2) weakly propagating (RP2), having a critical surface heat flux density of at least 8, but not more than 11 kilowatts per square meter;
3) moderately spreading (RPZ), having a critical surface heat flux density of at least 5, but not more than 8 kilowatts per square meter;
4) highly propagating (RP4), having a critical surface heat flux density of less than 5 kilowatts per square meter.

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

1) with low smoke generation capacity (D1), having a smoke generation coefficient of less than 50 square meters per kilogram;
2) with moderate smoke-generating ability (D2), having a smoke generation coefficient of at least 50, but not more than 500 square meters per kilogram;
3) with high smoke-forming capacity (S), having a smoke generation coefficient of more than 500 square meters per kilogram.

Based on the toxicity of combustion products, combustible building materials are divided into the following groups in accordance with Table 2 of the appendix to this Federal Law:
1) low-hazard (T1);
2) moderately dangerous (T2);
3) highly dangerous (HH);
4) 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
Flammability	NG	G1	G1	G2	G2	G4
Flammability	—	IN 1	IN 1	AT 2	AT 2	AT 3
Smoke generating ability	—	D1	D3+	D3	D3	D3
Toxicity of combustion products	—	T1	T2	T2	T3	T4
Flame propagation over flooring surfaces	—	RP1	RP1	RP1	RP2	RP4

Fire Hazard Properties construction class fire hazard of building materials depending on groups
materials KM0 KM1 KM2 KM3 KM4 KM5
Flammability NG G1 G1 G2 G2 G4
Flammability - B1 B1 B2 B2 B3
Smoke generating ability - D1 D3+ D3 D3 D3
Toxicity of combustion products - T1 T2 T2 T3 T4
Flame spread over the surface for flooring - RP1 RP1 RP1 RP2 RP4

The flammability group is conditional characteristic of a certain material, reflecting its ability to burn. In relation to drywall, it is determined by conducting a special flammability test, the conditions of which are regulated by GOST 3024-94. This test is also carried out for other finishing materials, and based on the results of how the material behaves on the test bench, it is assigned one of three flammability groups: G1, G2, G3 or G4.

Is drywall flammable or non-flammable?

All building materials are divided into two main groups: non-combustible (NG) and combustible (G). To qualify as non-combustible, the material must meet a number of requirements that are imposed on it during the testing process. A sheet of drywall is placed in an oven heated to a temperature of about 750 ° C and kept there for 30 minutes. During this time, the sample is monitored and a number of parameters are recorded. Non-combustible material must:

• increase the oven temperature by no more than 50 °C
• give a steady flame for no more than 10 s
• decrease in weight by no more than 50%

Plasterboard sheets do not meet these requirements and are therefore classified in group G (flammable).

Drywall flammability group

Combustible building materials also have their own classification and are divided into four flammability groups: G1, G2, G3 and G4.

The table below illustrates the standards that a material must meet to receive one of the four groups.

The specified parameters refer to samples that have passed the test using Method II, according to GOST 3024-94. This method involves placing the sample in a combustion chamber, in which it is exposed to a flame on one side for 10 minutes so that the temperature in the furnace ranges from 100 to 350 ° C, depending on the distance from the bottom edge of the sample.

In this case, the following characteristics are measured:

• Flue gas temperature
• The time it takes for the flue gases to reach their highest temperature
• Weight of the test sample before and after the test
• Dimensions of damaged surface
• Does the flame spread to that part of the samples that is not heated?
• Duration of burning or smoldering both during heating and after completion of exposure
• Time it takes for the flame to spread to the entire surface
• Does the material burn through?
• Is the material melting?
• Visual change appearance sample

Having collected and analyzed all the above indicators obtained in laboratory conditions, the material is assigned to one or another flammability group. Based on the figures that were recorded when testing a gypsum board sheet with dimensions of 1000x190x12.5 mm according to Method ll described above, it was found that the flammability group of plasterboard is G1. According to this group, the temperature of its flue gases does not exceed 135 °C, the degree of damage along the length of the sample is no more than 65%, damage by weight is no more than 20%, and the self-combustion time is zero.

Watch a visual process of testing drywall for flammability in the following video:

Fire hazard class

Standard partitions on a metal frame made of plasterboard sheets medium density 670 kg/m³ and a thickness of 12.5 mm according to GOST 30403-96 belong to the fire hazard class K0 (45). This means that when an unloaded material was exposed to fire for 45 minutes, no vertical or horizontal damage was recorded in it, and there was no combustion or smoke formation.

At the same time, in practice, the load-bearing capacity of a single-layer plasterboard partition is lost after just 20 minutes of fire exposure to the surface of the material. In addition, it should be taken into account that the fire safety of a particular plasterboard partition will depend on its design. Is it installed on metal carcass or at wooden sheathing whether there is a layer of insulation inside and whether it is flammable.

In addition to fire hazard and flammability, such characteristics as toxicity group of combustion products, smoke-generating ability group and flammability group are also applicable to plasterboard.

In terms of toxicity of combustion products, gypsum plasterboard sheets are classified as low-hazard (T1). The smoke-forming ability of a material characterizes it as having a low smoke-forming ability (D1) with a smoke generation coefficient of no more than 50 m²/kg (smoke optical density). For comparison, wood during smoldering has a value of this coefficient equal to 345 m²/kg. Flammability group for plasterboard B2 - moderately flammable materials.

Read also:

Fire-technical classification of building materials, structures, premises, buildings, elements and parts of buildings is based on their division according to properties that contribute to the occurrence of dangerous fire factors and its development - fire danger, and according to the properties of resistance to the effects of fire and the spread of its dangerous factors - fire resistance.

CONSTRUCTION MATERIALS

Building materials are characterized only by fire hazard.
The fire hazard of building materials is determined by the following fire-technical characteristics: flammability, flammability, flame spread over the surface, smoke-generating ability and toxicity.

Flammability of building materials.

Construction materials are divided into non-flammable (NG) And flammable (G). Combustible building materials are divided into four groups:

• G1(low flammability);
• G2(moderately flammable);
• G3(normally flammable);
• G4(highly flammable).

Flammability and flammability groups of building materials are established according to GOST 30244.

Flammability of building materials.

Combustible building materials are divided into three groups based on flammability:

• IN 1(flammable);
• AT 2(moderately flammable);
• AT 3(highly flammable).

Flammability groups of building materials are established according to GOST 30402.

Spread of flame over the surface of building materials.

Combustible building materials are divided into four groups according to the spread of flame over the surface:

• RP1(non-proliferating);
• RP2(low spreading);
• RP3(moderately spreading);
• RP4(highly spreading).

Groups of building materials for flame propagation are established for the surface layers of roofs and floors, including carpets, according to GOST 30444 (GOST R 51032-97).

Smoke-forming ability of building materials.

Combustible building materials are divided into three groups according to their smoke-generating ability:

• D1(with low smoke-generating ability);
• D 2(with moderate smoke-generating ability);
• DZ(with high smoke-generating ability).

Groups of building materials according to smoke-generating ability are established according to GOST 12.1.044.

Toxicity of building materials.

Combustible building materials are divided into four groups based on the toxicity of combustion products:

• T1(low hazard);
• T2(moderately dangerous);
• TK(highly dangerous);
• T4(extremely dangerous).

Groups of building materials based on the toxicity of combustion products are established according to GOST 12.1.044.

BUILDING CONSTRUCTION

Building structures are characterized by fire resistance and fire hazard.
The fire resistance indicator is fire resistance limit, the fire hazard of a structure is characterized by Class her fire danger.

Fire resistance limit of building structures.

Fire resistance limit building structures is established by the time (in minutes) of the onset of one or sequentially several, normalized for a given design, signs of limit states:

• loss of bearing capacity (R);
• loss of integrity (E);
• loss of thermal insulation ability (I).

Fire resistance limits of building structures and their symbols installed according to GOST 30247.

In this case, the fire resistance limit of windows is established only by the time of loss of integrity (E).

Fire hazard class of building structures.

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

• KO(non-fire hazardous);
• K1(low fire hazard);
• K2(moderate fire hazard);
• short circuit(fire hazardous).

The fire hazard class of building structures is established according to GOST 30403.

The Technical Code of Standard Practice establishes the fire-technical classification of building materials, products, structures, buildings and their elements. This regulatory act regulates the classification of materials, products and structures by fire hazard depending on fire-technical characteristics, as well as determination methods.

The fire hazard of building materials is determined by the following fire-technical characteristics or their combination:

Flammability;

Flammability;

Spread of flame over the surface;

Toxicity of combustion products;

Smoke generating ability.

Building materials, depending on the values ​​of flammability parameters determined according to GOST 30244, are divided into non-combustible
and flammable. For building materials containing only inorganic (non-flammable) components, the characteristic is “flammability”
not determined.

Combustible building materials are divided depending on:

1. Values ​​of flammability parameters determined according to GOST 30244 into flammability groups:

G1, slightly flammable;

G2, moderately flammable;

G3, normally flammable;

G4, highly flammable.

2. Values ​​of critical surface heat flux density according to GOST 30402 for flammability groups:

B1, flame retardant;

B2, moderately flammable;

B3, highly flammable.

3. B values ​​of critical surface heat flux density according to GOST 30444 into groups for flame propagation:

RP1, non-distributing;

RP2, weakly spreading;

RP3, moderately spreading;

RP4, highly spreading.

4. Lethal effect of gaseous combustion products from the mass of material per unit volume of the exposure chamber
according to GOST 12.1.044 into groups according to the toxicity of combustion products:

T1, low hazard;

T2, moderately dangerous;

T3, highly hazardous;

T4, extremely dangerous.

4. Values ​​of the smoke generation coefficient according to GOST 12.1.044 into groups according to smoke generation ability:

D1, with low smoke-generating ability;

D2, with moderate smoke-generating ability;

D3, with high smoke-generating ability.

Flammability is the ability of materials to withstand exposure to flame. This characteristic important for any construction product. The flammability group of the material is established in accordance with legally designated parameters. Based on these standards, the building material may turn out to be non-flammable, which is denoted by the abbreviation NG, or it will be assigned one of the flammability groups: G1 or G2, G3, G4.

Flammability classes

The flammable properties of a material become the basis for assigning it to one of the classes.

Non-combustible materials do not burn when exposed to air, but their interaction with another environment can lead to the formation of flammable products. For example, if a non-flammable material comes into contact with pure oxygen.

Non-flammable materials are capable of ignition if they are in an ignition source. As soon as the exposure to fire stops, the combustion process stops.

Combustible materials have the property of igniting even without exposure to flame, for example, with a sharp increase in temperature or upon impact. Combustion of materials of this class continues even when the flame source is eliminated.

Non-combustible materials belong to the NG flammability group. However, their number is limited, and many products with flammability group G2, that is, moderately flammable, are used in construction. There are also more flammable building materials that belong to the flammability group G3 (normally flammable) or flammability group G4 (highly flammable). Their use requires additional precautions fire protection and perhaps not at all construction sites.

Flammability groups

The flammability group of a building material allows you to assess the likelihood of fire. Based on this indicator, the fire hazard category of the room, the entire building or structure is calculated, and a set of measures to eliminate the fire is determined.

The non-combustible category includes brick, concrete, asbestos, stone wool. They have the most high degree fire resistance and safe for any constructed objects, including buildings social infrastructure.

Non-combustible building materials are classified based on their ability to ignite.

Products belonging to group G1 are classified as low-flammable materials. They are unable to burn outside a flame source. This group includes cellular polycarbonate.

Moderately flammable building materials are marked G2. The time of their independent combustion outside the flame source should not exceed 30 seconds. PVC siding has these properties.

The group of normally combustible materials marked G3 includes construction products that continue to burn for 300 seconds after the flame source disappears. The temperature of the flue gases formed during their combustion should not exceed 450ºС.

For highly flammable materials, which are classified as group G4, the indicators are similar to group G3. A distinctive characteristic is the temperature of the flue gases: it exceeds 450ºС. Polystyrene foam thermal insulator, both foamed and extruded, is marked G3 and G4.

In addition to combustion conditions, other properties of building products are also studied. The ability of building materials to ignite allows them to be classified as low-flammable, moderately flammable or flammable. During combustion, building materials can release toxic substances. Based on their toxicity, products are divided into low-hazardous, moderately hazardous, highly hazardous and extremely hazardous. The smoke generation intensity of building products is also examined. It may be low, moderate or high.

All these properties are indicated in the certificate fire safety and are taken into account by designers and builders.

Application in construction

The use of a building material on any site may be limited by the degree of fire resistance declared for it. The maximum requirements apply to social infrastructure facilities, the minimum requirements to low-rise private buildings.

If a school is being built or kindergarten, a healthcare facility, the building is classified as fire resistance class K0. The building materials used in this project must have maximum fire resistance. To determine which products of which flammability class are acceptable for a designated object, you need to know its fire hazard class.

Confirmation of class and degree of flammability

Both Russian and foreign building materials must have confirmation of the degree and class of their actual flammability. This characteristic is not specified by the manufacturer and is determined during laboratory tests. The test results are recorded in the appropriate laboratory report.

An accredited fire laboratory has the right to issue such a conclusion. There are several of them on the territory of Russia, and the conclusions they issue are subsequently used by builders and designers when choosing building materials for a particular project.

Fire testing of building materials

The behavior of a material or system of materials under fire conditions is tested during fire tests. The more resistant a building material is to flame, the lower the flammability group assigned to it will be.

During full-scale fire tests, various parameters are assessed, and based on their results, the product receives a fire safety certificate, where its properties are recorded. The validity period of the received certificate is limited to several years. When the document expires, the product must be sent again to the laboratory, where its characteristics will be confirmed through new tests.

Conducting full-scale fire tests in Russia is possible in an accredited laboratory. Such laboratories are located at the Ministry of Emergency Situations of Russia, the Research Institute named after. Kucherenko.

Testing of materials and building systems takes place in a special oven. Based on the test results, a protocol is drawn up. The document indicates not only the material being tested, but also the customer who carried out these studies, as well as the organization that performed the tests.

In accordance with Federal Law No. 123-FZ of July 22, 2008, the fire-technical classification of construction products - buildings, structures and construction materials - is based on their assessment:

· according to fire danger, i.e. properties that contribute to the occurrence of dangerous fire factors and its development;

· fire resistance , i.e. properties of resistance to the effects of fire and the spread of its hazardous factors.

Fire hazard analysis consists of determining the quantity and fire hazardous properties of substances and materials, the conditions for their ignition, the characteristics of building structures, buildings and structures, the possibility of fire spreading and assessing the danger to people, etc.

Construction Materials are characterized only fire hazard. It is determined by the following characteristics: flammability, flammability, flame spread over the surface, toxicity, smoke-generating ability.

Fire hazardous properties are primarily associated with the flammability of substances and materials, i.e. with their ability to burn, which in turn is characterized by the behavior of a sample of material in a flame heat source and after its removal. In accordance with GOST 30244-94, solid materials are divided into non-flammable (NG) and combustible (G).

Non-flammable substances and materials are not capable of spontaneous combustion in air, while flammable substances are capable of spontaneous combustion, ignite from an ignition source and support the development of combustion.

Combustible materials, depending on the temperature of the flue gases, the intensity of combustion and the duration of spontaneous combustion, are in turn divided into four flammability groups:

· G1 (low flammability);

· G2 (moderately flammable);

· G3 (normally flammable);

· G4 (highly flammable).

Materials of group G1 are unable to burn on their own; they burn only in the presence of more combustible materials such as, for example, materials of group G4, which burn well on their own until complete burnout. Group G4 includes materials of increased fire hazard - polyurethane foams, polystyrene foams and similar low-density organic materials that intensively develop combustion and are capable of forming burning melts.

The flammability of building materials is determined by the ignition time at given values ​​of the surface heat flux density. By flammability materials are divided (GOST 30402-96) into three groups:

· IN 1 (flammable);

· AT 2 (moderately flammable);

· AT 3 (highly flammable).

Flame propagation is assessed by the length of flame propagation along the surface and the critical surface heat flux density, as well as the ignition time of the sample. Combustible building materials by flame spread over the surface are divided (GOST R 51032-97) into four groups:

· RP1 (non-proliferating);

· RP2 (low spreading);

· RP3 (moderately spreading);

· RP4 (highly spreading).

Smoke generation coefficient is an indicator characterizing the optical density of smoke generated during flaming combustion or thermal-oxidative destruction (smoldering) of a certain amount solid(material). Combustible building materials according to smoke-forming ability are divided (GOST 12.1.044) into three groups:

· D1 (with low smoke-generating ability);

· D 2 (with moderate smoke-generating ability);

· DZ (with high smoke-generating ability).

The toxicity indicator of combustion products is the ratio of the amount of material per unit volume of a closed space in which gaseous products formed during combustion of the material cause the death of 50% of experimental animals. Combustible building materials by toxicity Combustion products are divided according to GOST 12.1.044 into four groups:

· T1 (low hazard);

· T2 (moderately dangerous);

· TK (highly dangerous);

· T4 (extremely dangerous).

All fire hazardous properties listed above affect the comprehensive assessment of the material - its fire hazard class

Fire hazard properties of building materials	Fire hazard class of building materials depending on groups
KM0	KM1	KM2	KM3	KM4	KM5
Flammability	NG	G1	G1	G2	G2	G4
Flammability	-	IN 1	IN 1	AT 2	AT 2	AT 3
Smoke generating ability	-	D1	D3+	D3	D3	D3
Toxicity of combustion products	-	T1	T2	T2	T3	T4
Flame propagation over flooring surfaces	-	RP1	RP1	RP1	RP2	RP4

Building construction characterized by fire resistance and fire hazard. The main characteristic of a building structure is the ability to maintain load-bearing and/or enclosing functions in fire conditions, which is assessed fire resistance limit.

Fire resistance limit- this is the time during which a building structure resists the effects of fire or high temperature fire until the occurrence of one or successively several limit states for fire resistance, taking into account functional purpose designs. The main limit states include:

loss of load-bearing capacity due to collapse of the structure or the occurrence of extreme deformations ( R );

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

· loss of thermal insulation ability due to an increase in temperature on the unheated surface of the structure to the maximum values ​​for a given structure ( I );

The fire resistance limit of windows is established only by the time of loss of integrity ( E ).

The designation of the fire resistance limit consists of a letter indicating the corresponding limit state ( R , E , I ) and a figure corresponding to the time to achieve one of these states (the first in time) in minutes.

For example:

· R 120 - fire resistance limit 120 min - for loss of load-bearing capacity;

· RE 60 - fire resistance limit 60 min - for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;

· REI 30 - fire resistance limit 30 min - for loss of load-bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.

· If the design is standardized various fire resistance limits according to various signs of an attack limit state, then the designation may consist of two or more parts. For example, R 120/EI 60 or R 120/E90/I 60 .

According to fire danger in accordance with GOST 30403, building structures are divided into four classes:

· K0(non-fire hazardous);

· K1(low fire hazard);

· K2(moderate fire hazard);

· short circuit(fire hazardous).

The fire hazard of structures is established depending on the consequences of the impact of flame on the structure, including the following:

Availability thermal effect from combustion of construction materials;

· presence of flaming combustion of gases released during thermal decomposition of construction materials;

· extent of structural damage;

· fire hazard of the materials from which the structure is made.

The fire resistance of structures affects the fire resistance of the building. Special attention is given to the load-bearing elements of the building, which provide overall stability and the geometric immutability of the building during a fire. These include load-bearing walls, frames, columns, beams, crossbars, trusses, floors, etc. These structures are subject to the highest requirements for fire resistance, but only in relation to their loss of bearing capacity . Based on the fire resistance limits of building structures, the degree of fire resistance of buildings and structures is assigned. In accordance with SNiP 21-01-97, four degrees are established. I is characterized by the presence of basic building structures with a high fire resistance limit (from R 120, REI 120 to RE 30). The least fire-resistant - IV degree - fire resistance limits are not even established for it (for IV they are less than 15 minutes).

An important means of preventing fires and explosions is fire prevention, which is based on an assessment of the explosion and fire hazards of production. This assessment allows you to prescribe organizational and technical measures. Currently, according to NTB 105-95, production is categorized depending on the premises, buildings and structures in which they are located and on the flammable properties of substances and materials used in production. Explosion and fire hazardous premises are allocated to separate categories based on excess explosion pressure, because this parameter significantly influences the development of a fire in a building

Related information.

It is determined by the following fire-technical characteristics: flammability, flame spread over the surface, flammability, smoke-generating ability, toxicity of combustion products. These indicators establish a range of fire hazard indicators for fire retardant compounds to determine their scope of application in the construction and decoration of buildings and premises.

Flammability

Building materials are divided into non-combustible (NG) and combustible (G). Treated materials can have one of 4 groups: G1 - low-flammable, G2 - moderately flammable, G3 - normally flammable, G4 - highly flammable.
Flammability and flammability groups are established according to GOST 30244-94.

To carry out the flammability test, 4 samples are taken - boards treated with a fire retardant compound. A box is built from these samples. It is placed in a chamber containing 4 gas-burners. The burners are ignited in such a way that the flame acts on the lower surface of the samples. At the end of combustion, the following are measured: the temperature of the exhaust flue gases, the length of the damaged section of the sample, mass, and residual combustion time. Having analyzed these indicators, wood treated with a fire retardant composition is classified into one of four groups.

Flame Spread

Combustible building materials are divided into 4 groups based on the spread of flame over the surface: RP1 - non-propagating, RP2 - weakly spreading, RP3 - moderately spreading, RP4 - highly spreading.

GOST R 51032-97 regulates testing methods for building materials (including those treated with fire retardants) for flame propagation. To carry out testing, the sample is exposed to the heat of a radiation panel located at a slight angle and heated to a certain temperature. Depending on the heat flux density, the value of which is determined by the length of flame propagation along the sample, the material treated with a fire retardant composition is assigned to one of four groups.

Flammability

Combustible building materials are divided into groups according to flammability: B1 – hardly flammable, B2 – moderately flammable, B3 – highly flammable.

GOST 30402 defines methods for testing building materials for flammability. The group is determined depending on the heat flux of the radiation panel at which ignition occurs.

Smoke generating ability

According to this indicator, materials are divided into 3 groups: D1 - with low smoke-generating ability, D2 - with moderate smoke-generating ability, D3 - with high smoke-generating ability.
Smoke generating ability groups are established according to GOST 12.1.044. For testing, the sample is placed in a special chamber and burned. During combustion, the optical density of the smoke is measured. Depending on this indicator, wood with a fire retardant applied to it is classified into one of three groups.

Toxicity

Based on the toxicity of combustion products, there are 4 groups of materials: T1 - low-hazardous, T2 - moderately hazardous, T3 - highly hazardous, T4 - extremely hazardous. Toxicity groups are established according to GOST 12.1.044.

The most important quality of the material used in construction is its flammability. Flammability is the property of a material to resist the effects of flame. Therefore, five flammability groups are legally defined. Four groups of flammable materials and one non-flammable. IN Federal law No. 123 they are defined by abbreviations: G1, G2, G3, G4 and NG. Where NG stands for non-flammable.

The main indicator when determining the flammability group of a particular material is the burning time. The longer the material can withstand, the lower the flammability group. Burn time is not the only indicator. Also, during fire tests, the interaction of the material with the flame will be assessed, whether it will support combustion and to what extent.

The flammability group is inextricably linked with other parameters of the fire resistance of the material, such as flammability, release of toxic substances and others. Taken together, the fire resistance indicators make it possible to judge the flammability class. That is, the flammability group is one of the indicators for assigning a flammability class; it precedes it. Let's take a closer look at the elements of assessing the fire resistance of a material.

All substances in nature are divided into. Let's list them:

• Non-flammable. These are substances that cannot burn on their own. air environment. But even they can, when interacting with other media, be sources of formation of flammable products. For example, interacting with oxygen in the air, with each other or with water.
• Difficult to burn. Building materials that are difficult to combust can only ignite when exposed to an ignition source. Their further combustion cannot occur on their own when the ignition source ceases; they go out.
• Combustible. Combustible (combustible) building materials are defined as capable of ignition without an external ignition source. Moreover, they quickly ignite if such a source is available. Materials of this class continue to burn even after the ignition source disappears.

It is preferable to use non-combustible materials in construction, but not all are widely used construction technologies may be based on the use of products that may have such a remarkable property. More precisely, there are practically no such technologies.

The fire safety characteristics of building materials also include:

• flammability;
• flammability;
• the ability to release toxins when heated and burning;
• intensity of smoke formation at high temperatures.

Flammability groups

The tendency of building materials to burn is indicated by the symbols G1, G2, G3 and G4. This series begins with the flammability group of slightly flammable substances, designated by the symbol G1. The series ends with a group of highly flammable G4. Between them there is a group of materials G2 and G3, which are moderately flammable and normally flammable. These materials, including the weakly flammable G1 group, are mainly used in construction technologies.

The flammability group G1 shows that this substance or material can emit flue gases heated no higher than 135 degrees Celsius and is not capable of burning independently, without external ignition action (non-flammable substances).

For completely non-combustible building materials, fire safety characteristics are not studied and standards for them are not established.

Of course, the G4 group of materials also finds its application, but due to its high tendency to burn, it requires additional fire safety measures. An example of such additional measures could be a floor-by-floor fire-prevention cutoff made of steel inside the ventilation façade structure, if a windproof membrane with flammability group G4, that is, flammable, was used. In this case, the cutoff is designed to stop the flame inside the ventilation gap within one floor.

Application in construction

The use of materials in the construction of buildings depends on the degree of fire resistance of these buildings.

The main classification of building structures according to fire safety classes is as follows:

To determine which flammability materials are acceptable in the construction of a particular facility, you need to know the fire hazard class of this facility and the flammability groups of the building materials used. The fire hazard class of an object is established depending on the fire hazard of those technological processes that will take place in this building.

For example, for the construction of buildings for kindergartens, schools, hospitals or nursing homes, only materials of the flammability group NG are allowed.

In fire-hazardous buildings with fire resistance of the third level, low-fire K1 and moderate-fire K2, it is not allowed to carry out external cladding walls and foundations made of flammable and low-combustible materials.

For non-load-bearing walls and translucent partitions, materials can be used without additional fire hazard testing:

• structures made of non-combustible materials - K0;
• structures made from materials of group G4 - K3.

Any building structures should not spread latent combustion. There should be no voids in the wall partitions or the places where they are connected, which are separated from one another by continuous fillings made of flammable materials.

Confirmation of class and degree of flammability

Test of façade finishing materials for flammability. Video

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