What does the flammability group g4 mean. PB requirements for the use of building materials for production and storage facilities

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:

In accordance with the federal law of July 22, 2008 N 123-FZ, the fire-technical classification of construction products - buildings, structures and building materials - is based on their assessment:

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

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

Fire hazard analysis consists in 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 spread and the assessment of danger to people, etc.

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

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

Non-combustible substances and materials are not capable of self-combustion in air, and combustible ones 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 independent combustion, are in turn divided into four groups of combustibility:

· G1 (low combustible);

· G2 (moderately flammable);

· G3 (normally combustible);

· G4 (highly flammable).

Materials of group G1 are unable to burn independently, 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, expanded polystyrenes 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. Flammability materials are divided (GOST 30402-96) into three groups:

· IN 1 (flammable);

· IN 2 (moderately flammable);

· IN 3 (flammable).

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

· RP1 (non-propagating);

· RP2 (weakly propagating);

· RP3 (moderately spreading);

· WP4 (strongly spreading).

The smoke generation coefficient is an indicator that characterizes the optical density of smoke generated during flame combustion or thermal-oxidative destruction (smoldering) of a certain amount of a solid substance (material). Combustible building materials smoke generating capacity are divided (GOST 12.1.044) into three groups:

· D1 (with low smoke-forming ability);

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

· DZ (with high smoke generating capacity).

The index of toxicity of combustion products is the ratio of the amount of material to a unit volume of an enclosed space in which gaseous products formed during the combustion of a 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-risk);

· T2 (moderately dangerous);

· TK (highly dangerous);

· T4 (extremely dangerous).

All the given fire hazard properties affect the comprehensive assessment of the material - its fire hazard class

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 a fire, which is assessed fire resistance limit.

Fire resistance limit- this is the time during which the building structure resists the effects of fire or high fire temperatures before the occurrence of one or several fire resistance limit states in succession, taking into account the functional purpose of the structure. The main limit states are:

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

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

loss of heat-insulating ability due to temperature increase on the unheated surface of the structure to the limit values ​​for this structure ( I );

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

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

For example:

· R120 - fire resistance limit 120 min - by loss of bearing capacity;

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

· REI 30 - fire resistance limit of 30 min - in terms of loss of bearing capacity, integrity and heat-insulating capacity, regardless of which of the three limit states occurs earlier.

If, for the design, they are normalized various fire resistance limits according to various signs of the onset of the limit state, then the designation may consist of two or more parts. For example, R 120/EI 60 or R 120/E90/I 60 .

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

· K0(non-flammable);

· K1(low fire risk);

· K2(moderately fire hazardous);

· KZ(fire hazardous).

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

the presence of a thermal effect from the combustion of construction materials;

the presence of flame combustion of gases released during the thermal decomposition of construction materials;

the size of the damage to the structure;

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

The fire resistance of structures affects the fire resistance of a building. Particular attention is paid to the load-bearing elements of the building, which ensure the overall stability and geometric stability of the building in case of fire. These include load-bearing walls, frames, columns, beams, crossbars, trusses, ceilings, etc. These structures are subject to the highest requirements for fire resistance, but only in relation to their loss of bearing capacity . According to the limits of fire resistance 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 for it are not even established (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 hazard of production. Such an assessment allows you to assign 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 combustible properties of the substances and materials used in production. Explosive and fire-hazardous premises are allocated into separate categories according to the excess pressure of the explosion, tk. this parameter significantly affects the development of a fire in a building

Similar information.

1 Flammability classes
2 Flammability groups
3 Application in construction
4 Confirmation of the class and degree of flammability
5 Fire tests of objects
Flammability classes
All substances in nature are divided into flammability classes. Let's list them:

Non-combustible. These are substances that by themselves cannot burn in air. But even they can, when interacting with other media, be sources of the formation of combustible products. For example, interacting with oxygen in the air, with each other or with water.
Fire resistant. Difficult-to-combustible building materials can ignite only when exposed to an ignition source. Their further burning when the ignition source ceases to occur independently cannot occur, they go out.
combustible. Combustible (combustible) building materials are defined as capable of igniting without an external source of ignition. Moreover, they quickly ignite if such a source is available. Materials of this class continue to burn after the disappearance of the ignition source.
flammability group g1 what is it

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

The fire-fighting characteristics of building materials also include:

combustibility;
flammability;
the ability to release toxins when heated and burned;
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 combustibility group of slightly combustible substances, designated by the symbol G1. The series ends with a group of highly flammable G4s. Between them is a group of materials G2 and G3, which are moderately combustible and normally combustible. These materials, including the group of low combustible G1, are mainly used in building technologies.

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

For completely non-combustible building materials, fire safety characteristics are not investigated and standards are not established for them.
Of course, the group of materials G4 also finds its application, but due to the high tendency to burn, you require initial treatment with special fire-fighting compounds and subsequent treatments after the deadlines established by the fire inspectorate.

Application in construction
The use of materials in the construction of buildings depends on the degree of fire resistance of these buildings. how to get G1 for material

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

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

For example, for the construction of buildings of kindergartens, schools, hospitals or nursing homes, materials and insulation systems from the outside are allowed only for class PO K0. The same requirements have been developed for other types of building structures.

In fire hazardous buildings with fire resistance of the third level, low fire K1 and moderate fire K2, it is not allowed to perform external wall and foundation cladding from combustible and slow-burning materials.

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

structures made of non-combustible materials - K0;
Structures from materials of group G4 - K3.
Any building structures should not spread latent combustion. In the partitions of the walls, the places of their connection there should not be voids that are separated from one another by continuous fillings of combustible materials.

Confirmation of the class and degree of flammability
Any new material or system (design) must be supported by a technical certificate. This certificate authorizes the use in construction work of various materials in accordance with their fire safety rules set out in this document.

One of the chapters of the certificate is a listing of the mandatory fire hazard standards for a given material. For the first time, domestic and foreign products used in construction technology require confirmation by the fire inspection after standard fire resistance tests.

Fire tests of objects
This method of testing is carried out to establish the fire resistance of an object under construction or already erected. This property of the object depends on the fire hazard of the structural materials used in construction.

Fire tests on the territory of the Russian Federation are authorized to be carried out by such organizations as the Ministry of Emergency Situations of Russia, Research Institute "Experimental", ANO "Pozhaudit", Research Institute. Kucherenko and many others.
Testing of finishing materials for facades of buildings and internal elements is carried out in a special furnace. The protocol of these tests of testing materials for the degree of combustibility contains a reference to the customer and the organization that is authorized to conduct fire tests. The name of the tested structure is also indicated with a set of attached documentation.

Taking into account the weather conditions during the tests, the results obtained by heating and burning the samples used in the construction of the facility in the furnace are indicated. Also attached are photographs of structural elements before and after testing. A fire protocol is drawn up, in which all the test results are detailed.

According to the results of the tests set out in the fire protocol and the fire hazard class of the building, the customer is issued a conclusion on the compliance of the facility with fire safety requirements.

On escape routes in buildings, except for buildings with load-bearing and enclosing structures made of wood or other G4 materials, it is not allowed to use materials with a higher fire hazard than:

G1, V1, D2, T2- for finishing walls, ceilings and filling suspended ceilings in lobbies, stairwells, elevator lobbies;

G2, V2, D3, T3 or G2, V3, D2, T2- for finishing walls, ceilings and filling suspended ceilings in common corridors, halls and foyers;

G2, RP2, D2, T2- for floor coverings in lobbies, stairwells, elevator lobbies;

V2, RP2, D3, T2- for floor coverings in common corridors, halls and foyers.

IN production and storage facilities categories A, B and C1, in which flammable liquids are produced, used or stored, floors should be made of non-combustible materials or materials of flammability group G1.

Suspended ceiling frames in rooms and on escape routes should be made of non-combustible materials.

Fire hazard indicators of building materials

The fire hazard of building materials is characterized by the following: combustibility ( G), flammability ( IN), flame propagation over the surface ( RP), smoke-generating ability ( D), toxicity ( T).

From the above table it can be seen that the higher the number of group indicators, the higher the danger of this group of materials. In practice, when monitoring the values ​​of indicators, it is not necessary to remember, it is only necessary to make sure that in the material used, the numbers for the group indicators are either the same as in clause 6.25* of SNiP 21-01, or less.

We give, according to the GOSTs indicated in the table, individual values ​​​​(for example) of indicators for materials used for finishing walls, ceilings and filling suspended ceilings in lobbies, stairwells, elevator lobbies:

Duration of self-burning of group materials G1- 0 seconds, G4 over 300 seconds:

Flue gas temperature group materials G1- no more than 135 degrees C, G4- more than 450 degrees C;

Critical surface heat flux density at which stable flame combustion of materials occurs IN 1- 35 and more kW/sq.m;

Smoke generation coefficient of group materials D 2- over 10 to 100 incl. cubic meters/kg;

Toxicity index at an exposure time of 5 min of materials of the group T2- 70- 210 g/cu.m.

When carrying out repairs on evacuation routes and evacuation exits, paragraph 53 of the Fire Safety Rules in the Russian Federation should also be followed. PPB 01-03 prohibiting use combustible materials for finishes, cladding and wall painting and ceilings, as well as steps and landings on escape routes

(except for buildings with load-bearing and enclosing structures made of wood or other materials G4).

Appendix B of the Recommendations on improving the fire safety of roofing of the main buildings of operating TPPs. SO 153-34.03.357-2003 provides a list of some modern materials for the reconstruction and repair of roofing with subsections: waterproofing materials (with indicators G4, V2, RP4 or G4, V2, RP3) and heat-insulating materials (with indicators NG or G1 or G2 , V2, D2).

A combustibility group is a conditional characteristic of a certain material that reflects its ability to burn. With regard to drywall, it is determined by conducting a special test for combustibility, the conditions of which are regulated by GOST 3024-94. This test is also carried out in relation to other finishing materials, and according to 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 combustible or non-combustible?

All building materials are divided into two main groups: non-combustible (NG) and combustible (G). To get to the non-combustible, the material must meet a number of requirements that are imposed on it during the testing process. A drywall sheet 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 furnace temperature by no more than 50 °C
• give a steady flame for no more than 10 s
• decrease in mass by no more than 50%

Gypsum boards do not meet these requirements and are therefore classified in group G (combustible).

Drywall combustibility 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 in order to obtain one of the four groups.

The specified parameters refer to samples that have passed tests on the test of my 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 in such a way that the temperature in the furnace is in the range from 100 to 350 ° C, depending on the distance from the lower edge of the sample.

In this case, the following characteristics are measured:

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

Having collected and analyzed all the above indicators obtained in laboratory conditions, the material is assigned to one or another combustibility group. Based on the figures that were recorded when testing a GKL sheet with dimensions of 1000x190x12.5 mm according to Method ll described above, it was found that the drywall combustibility group 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 not more than 65%, damage by weight is not more than 20%, and the self-burning time is zero.

Video

See the visual process of testing drywall for combustibility in the following video:

Fire hazard class

Standard partitions on a metal frame made of drywall sheets with an average density of 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 the unloaded material was exposed to fire for 45 minutes, no vertical or horizontal damage was recorded in it, and there was no combustion and smoke formation.

At the same time, in practice, the bearing capacity of a single-layer plasterboard partition is lost after 20 minutes of fire impact on the surface of the material. In addition, it should be borne in mind that the fire safety of a particular drywall partition will depend on its design. Is it installed on a metal frame or on a wooden crate, is there a layer of insulation inside and is it combustible.

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

According to the toxicity of combustion products, GKL sheets are classified as low-hazard (T1). The smoke-generating ability of the material characterizes it as having a low smoke-generating ability (D1) with a smoke generation coefficient of not more than 50 m² / kg (smoke optical density). For comparison, smoldering wood has a value of this coefficient equal to 345 m² / kg. The flammability group of drywall B2 is moderately flammable materials.