Groups of materials on fire safety. Fire hazard indicators of fire retardants

"Fire safety of buildings and structures" on fire-technical classification building materials, as well as the provisions of other regulatory documents on fire safety to which this document refers.

For non-combustible building materials, other indicators of fire hazard are not determined or standardized.

flammability- the ability of substances and materials to ignite.

ignition - the beginning of flame combustion under the influence of an ignition source, at present standard test characterized by a stable flame combustion.

ignition time- the time from the start of the test to the onset of a stable flame combustion.

stable flame combustion- combustion, continuing until the next exposure of the sample to the flame from the ignition source.

Radiant heat flux acting on a unit of sample surface.

Minimum value surface heat flux density at which stable flame combustion occurs.

flame spread- the spread of flame combustion over the surface of the sample as a result of the impact specified in this standard;

surface heat flux density (PPTP)- radiant heat flux acting on a unit of sample surface;

critical surface heat flux density (KPPTP)- the magnitude of the heat flux at which the flame propagation stops.

In clause 5.7 of SNiP 21-01-97 * it is established that combustible building materials are divided into three groups according to their smoke-forming ability:

D1 (with small smoke generating ability);

D2 (with moderate smoke-generating ability);

D3 (with high smoke-generating ability).

Groups of building materials for smoke-forming ability are established in accordance with GOST 12.1.044-89 "Occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination". This document contains the following provisions in relation to the coefficient of smoke production.

Smoke production coefficient- an indicator characterizing the optical density of smoke formed during flame combustion or thermal oxidative destruction (smoldering) of a certain amount of a solid (material) under special test conditions.

The value of the smoke production coefficient should be used to classify materials according to their smoke generating ability. There are three groups of materials:

with low smoke-generating ability - smoke production coefficient up to 50 m2kg-1 inclusive;

with a moderate smoke-generating ability - the coefficient of smoke production of St. 50 to 500 m2kg-1 inclusive;

with a high smoke-generating ability - the coefficient of smoke production of St. 500 m2kg-1.

The value of the smoke production coefficient should be included in the standards or technical conditions on the solids and materials.

In accordance with clause 5.8 of SNiP 21-01-97 *, combustible building materials are divided into four groups according to the toxicity of combustion products:

T1 (low hazard);

T2 (moderately dangerous);

T3 (highly hazardous);

T4 (extremely dangerous).

Groups of building materials for toxicity of combustion products are established in accordance with GOST 12.1.044-89 "Occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination". The named document in relation to the toxicity index of combustion products polymer materials provides the following.

The indicator of toxicity of combustion products is the ratio of the amount of material to a unit volume of a closed space in which gaseous products formed during the combustion of the material cause the death of 50% of the experimental animals.

The value of the toxicity indicator of combustion products should be used for a comparative assessment of polymer materials, and also included in the technical specifications and standards for finishing and thermal insulation materials... The classification of materials according to the value of the toxicity index of combustion products is given in the table.

The essence of the method for determining the toxicity indicator consists in burning the material under study in a combustion chamber at a given heat flux density and revealing the dependence of the lethal effect of gaseous combustion products on the mass of the material per unit volume of the exposure chamber.

The table, which is established in GOST 12.1.044-89, is reproduced in table 2 of the appendix to the commented Law (see the commentary to the specified table).

11. In accordance with Part 11 of the commented article, classes of fire hazard of building materials are distinguished depending on the groups of fire hazard of building materials. These classes - KM0, KM1, KM2, KM3, KM4 and KM5 - are shown in Table 3 of the Appendix to the commented Law. It should be noted that the allocation of these classes is an innovation, since earlier in the normative documents on fire safety (first of all, in SNiP 21-01-97 * "Fire safety of buildings and structures") only groups of fire hazard of building materials were singled out.

12. At ch. 12

The classification of building materials for fire hazard is based on their properties and ability to form dangerous factors fire.

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

1.flammability;

2. flammability;

3. the ability to spread the 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 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 meet at least one of the parameter values specified in part 4 of this article are classified as combustible. Combustible building materials are classified into the following groups:

1.mildly flammable (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 the mass of the test sample is not more than 20 percent, the duration of self-combustion is 0 seconds;

2. moderately flammable (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 the mass of the test sample is not more than 50 percent, the duration of self-burning is not more than 30 seconds;

3.Normally combustible (G3), 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 the mass of the test sample is not more than 50 percent, the duration of self-combustion is not more than 300 seconds;

4. 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 the mass of the test sample is more than 50 percent, the duration of self-combustion is more than 300 seconds.

5. For materials belonging to flammability groups G1 - G3, 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 of fire hazard are not determined or standardized.

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

· Hardly 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 (B3), having a critical surface heat flux density of less than 20 kilowatts per square meter.

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

· Non-proliferating (RP1), having a critical surface heat flux density of more than 11 kilowatts per square meter;

· Weakly propagating (RP2), having a critical surface heat flux density of at least 8, but not more than 11 kilowatts per square meter;

· Moderately spreading (RP3), having a critical surface heat flux density of at least 5, but not more than 8 kilowatts per square meter;

· Highly propagating (RP4), having a critical surface heat flux density of less than 5 kilowatts per square meter.

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

With low smoke-generating ability (D1), having a smoke production coefficient of less than 50 square meters per kilogram;

· With moderate smoke-generating ability (D2), having a smoke production coefficient of at least 50, but not more than 500 square meters per kilogram;

· With a high smoke-generating ability (D3), having a smoke production coefficient of more than 500 square meters per kilogram.

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

· Low-hazard (T1);

In accordance with SNiP 21-01-97 "Fire safety of buildings and structures", the fire hazard of building materials is characterized by the following indicators:

flammability;

the spread of the flame over the surface;

smoke-generating ability;

toxicity of combustion products.

By combustibility, building materials are divided into non-combustible (NG) and combustible (G). Combustible building materials are classified into four groups:

G1 - slightly flammable;

G2 - moderately flammable;

G3 - normally flammable;

G4 - highly flammable.

According to their flammability, combustible building materials are divided into three groups:

81 - hardly flammable;

82 - moderately flammable;

83 - flammable.

According to the spread of the flame over the surface, combustible building materials are divided into four groups:

RP1 - flame retardant;

RP2 - weakly spreading flame;

RP3 - moderately spreading flame;

RP4 - highly spreading flames.

The group of building materials for flame propagation is established only for the surface layers of the roof and floors (including for carpets).

According to their smoke-generating ability, combustible building materials are divided into three groups:

D1 - with low smoke-generating ability;

D2 - with moderate smoke-forming ability;

D3 - with high smoke-generating ability;

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

T1 - low-hazard;

T2 - moderately dangerous;

T3 - highly hazardous;

T4 - extremely dangerous.

Fire and explosion hazard conditions when using substances and materials

To ensure the fire and explosion safety of the processes of production, processing, storage and transportation of substances and materials, it is necessary to use data on the indicators of the fire and explosion hazard of substances and materials with the safety factors given in table. 3

Method of preventing fire, explosion	Regulated parameter	Fire and explosion safety conditions
Preventing the formation of a flammable environment


Limiting the flammability and combustibility of substances and materials	Flammability of the substance (material)	The flammability of the substance (material) should not be more regulated
Prevention of education in
combustible environment (or introduction into
her) ignition sources

The reproducibility of the method for determining the fire hazard indicator at a confidence level of 95%;

Safe temperature, ° С;

Flash point, ° С;

Flash point in a closed crucible, ° С;

Upon receipt of substances and materials, use, storage, transportation, processing and disposal.

To establish fire safety requirements for the construction of buildings, structures and systems fire protection the classification of building materials by fire hazard is used.

Indicators of fire and explosion hazard and fire hazard of substances and materials

The list of indicators required to assess the fire and explosion hazard and fire hazard of substances and materials, depending on their state of aggregation, is given in Table 1 of the Appendix to the Federal Law ФЗ-123 ("Technical Regulations on Fire Safety").

Methods for determining the indicators of fire and explosion hazard and fire hazard of substances and materials are established regulatory documents on fire safety.

Indicators of fire and explosion hazard and fire hazard of substances and materials are used to establish requirements for the use of substances and materials and calculate fire risk.

The list of indicators required to assess the fire hazard of substances and materials, depending on their state of aggregation

Fire hazard indicator	Substances and materials in various aggregate states			Dust
Fire hazard indicator	gaseous	liquid	solid	Dust
Safe experimental maximum clearance, millimeter	+	+	-	+
Release of toxic combustion products from a unit mass of fuel, kilogram per kilogram	-	+	+	-
Flammability group	-	-	+	-
Flammability group	+	+	+	+
Flame spread group	-	-	+	-
Smoke production coefficient, square meter per kilogram	-	+	+	-
Flame emissivity	+	+	+	+
Fire and explosion hazard index, Pascal per meter per second	-	-	-	+
Flame spread index	-	-	+	-
Oxygen index, volume percent	-	-	+	-
Concentration limits of flame propagation (ignition) in gases and vapors, volume percent, dusts, kilogram per cubic meter	+	+	-	+
Concentration limit diffusion combustion gas mixtures in the air, volume percent	+	+	-	-
Critical surface heat flux density, Watt per square meter	-	+	+	-
Linear speed of flame propagation, meter per second	-	-	+	-
Maximum speed of flame propagation along the surface flammable liquid, meter per second	-	+	-	-
Maximum explosion pressure, Pascal	+	+	-	+
Minimum phlegmatizing concentration of gaseous phlegmatizer, volume percent	+	+	-	+
Minimum ignition energy, Joule	+	+	-	+
Minimum explosive oxygen content, volume percent	+	+	-	+
Lower working heat of combustion, kiloJoule per kilogram	+	+	+	-
Normal speed of flame propagation, meter per second	+	+	-	-
Indicator of toxicity of combustion products, gram per cubic meter	+	+	+	+
Oxygen consumption per unit mass of fuel, kilogram per kilogram	-	+	+	-
The limiting velocity of the breakdown of the diffusion flame, meter per second	+	+	-	-
Explosion pressure rise rate, megaPascal per second	+	+	-	+
The ability to burn when interacting with water, atmospheric oxygen and other substances	+	+	+	+
Ignition capacity under adiabatic compression	+	+	-	-
Spontaneous combustion	-	-	+	+
Exothermic decomposition	+	+	+	+
Ignition temperature, degree Celsius	-	+	+	+
Flash point, degree Celsius	-	+	-	-
Autoignition temperature, degree Celsius	+	+	+	+
Smoldering temperature, degree Celsius	-	-	+	+
Temperature limits of flame spread (ignition), degree Celsius	-	+	-	-
Specific mass burnup rate, kilogram per second per square meter	-	+	+	-
Specific heat of combustion, Joule per kilogram	+	+	+	+

Classification of substances and materials ( excluding construction, textile and leather materials) by fire hazard

The classification of substances and materials by fire hazard is based on their properties and the ability to form hazardous factors of fire or explosion.

In terms of flammability, substances and materials are divided into the following groups:
1) non-combustible- substances and materials incapable of burning in the air. Non-flammable substances can be fire-and-explosive (for example, oxidizers or substances that emit flammable products when interacting with water, atmospheric oxygen or with each other);
2) hardly combustible- Substances and materials capable of burning in air when exposed to an ignition source, but incapable of independently burning after its removal;
3) combustible- substances and materials that can ignite spontaneously, as well as ignite under the influence of an ignition source and burn independently after its removal.

Test methods for combustibility of substances and materials are established by fire safety regulations.

Fire hazard classification of construction, textile and leather materials

Fire hazard classification of construction, textile and leather materials is based on their properties and their ability to form hazardous fire factors.

The fire hazard of construction, textile and leather materials is characterized by the following properties:
1) flammability;
2) flammability;
3) ability to spread a flame over a surface;
4) smoke generating ability;
5) toxicity of combustion products.

Flame propagation speed over the surface

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

1) non-proliferating (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 (WP3) 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 ..

Smoke-generating ability

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

1) with low smoke-generating ability (D1) having a smoke production coefficient of less than 50 square meters per kilogram;

2) with moderate smoke-generating ability (D2) having a smoke production coefficient of at least 50, but not more than 500 square meters per kilogram;

3) with high smoke-generating ability (D3) having a smoke production coefficient of more than 500 square meters per kilogram ..

Toxicity

According to the toxicity of combustion products, combustible building materials are divided into the following groups in accordance with Table 2 Appendices to Federal Law No. 123-FZ:

1) low hazard (T1);
2) moderately hazardous (T2);
3) highly hazardous (T3);
4) extremely dangerous (T4).

Classification of combustible building materials by the value of the toxicity index of combustion products

Hazard Class	Indicator of toxicity of combustion products depending on the exposure time
Hazard Class	5 minutes	15 minutes	30 minutes	60 minutes
Low hazard	more than 210	more than 150	more than 120	more than 90
Moderately hazardous	more than 70, but not more than 210	more than 50, but not more than 150	more than 40, but not more than 120	more than 30, but not more than 90
Highly hazardous	more than 25, but not more than 70	more than 17, but not more than 50	more than 13, but not more than 40	more than 10, but not more than 30
Extremely dangerous	no more than 25	no more than 17	no more than 13	no more than 10

Classification of certain types of substances and materials

For floor carpets, the flammability group is not defined.

In terms of flammability, textile and leather materials are divided into flammable and hardly flammable. A fabric (non-woven fabric) is classified as flammable if the following conditions are met during testing:

1) the flame combustion time of any of the samples tested with ignition from the surface is more than 5 seconds;

2) any of the samples tested when ignited from the surface burns out to one of its edges;

3) cotton wool ignites under any of the test specimens;

4) a surface flash of any of the samples extends more than 100 millimeters from the ignition point from the surface or edge;

5) average length the charring area of any of the samples tested by exposure to a flame from a surface or edge is more than 150 millimeters.

For the classification of building, textile and leather materials, the value of the flame spread index (I) should be used - a conditional dimensionless indicator characterizing the ability of materials or substances to ignite, spread a flame over a surface and generate heat. According to the spread of flame, materials are divided into the following groups:

1) that do not spread the flame over the surface, having a flame spread index of 0;

2) slowly spreading flame over the surface, having a flame spread index of no more than 20;

3) rapidly spreading flame over the surface, having a flame spread index of more than 20.

Test methods for determining the classification indicators of fire hazard of construction, textile and leather materials are established by fire safety regulations

The most important quality of the material used in construction is its flammability. Flammability is the property of a material to withstand the effects of flame. Therefore, five groups of flammability are legally defined. Four groups of combustible materials and one non-combustible. IN Federal law No. 123 they are defined by abbreviations: Г1, Г2, Г3, Г4 and НГ. Where NG stands for non-flammable.

The main indicator in 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 evaluated, whether it will support combustion and to what extent.

The flammability group is inextricably linked with other parameters of the material's fire resistance, such as flammability, release of toxic substances and others. All together, the indicators of fire resistance make it possible to judge the class of flammability. That is, the flammability group is one of the indicators of the flammability class assignment, 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 subdivided into. Let's list them:

Non-flammable. 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.
Hardly combustible. Hardly combustible building materials can ignite only when exposed to an ignition source. Their further combustion, when the ignition source stops acting, cannot occur independently, they go out.
Combustible. Combustible (combustible) building materials are defined as being capable of being ignited without an extraneous ignition source. Moreover, they quickly ignite, if such a source is available. Materials of this class continue to burn even after the ignition source has disappeared.

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 wonderful property... More precisely, there are practically no such technologies.

The fire-fighting characteristics of building materials also include:

flammability;
flammability;
the ability to release toxins when heated and burned;
the 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 row begins with the flammability group of low-flammable substances, indicated by the symbol G1. The row ends with a group of highly flammable G4. Between them is a group of materials G2 and G3, which are moderately flammable and normally flammable. These materials, including the group of low-combustible G1, are mainly used in construction technologies.

The flammability group G1 shows that this substance or material can emit flue gases heated to no higher than 135 degrees Celsius and independently, without an external ignition action, are not capable of burning (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 G4 group of materials also finds its application, but due to its high propensity to combustion, it requires additional fire safety measures. As an example of such additional measures, a floor fire cut-off made of steel inside the structure of the ventilation facade can be used, if windproof membrane with a flammability group G4, that is, combustible. In this case, the cut-off is designed to stop the flame inside the vent gap within the same floor.

Application in construction

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

Main classification building structures by fire safety class it looks like this:

To determine which materials of which flammability are acceptable in the construction of a particular facility, you need to know the fire hazard class of this facility and the flammability group of the building materials used. The fire hazard class of the facility 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, materials only and of the NG flammability group 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 perform outer cladding walls and foundations made of combustible and hardly combustible materials.

For curtain walls and translucent partitions, materials can be used without additional fire tests:

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

Any building structures must not spread latent combustion. In the partitions of the walls, in the places of their connection, there should be no voids that are separated from one another by continuous fillings of combustible materials.