So g4. Classification of building materials according to fire hazard. Is penoplex flammable or not?

As part of the exchange of materials with users of our site, we publish a table of flammability of materials, which shows how flammable certain materials are.

This sign was sent to us by Vladimir Volodin from Krasnodar in response to my comments in his thread on ForumHouse. Anyone interested can read how he built a frame house.

And this plate is interesting because it indicates the main building materials for example and this plate well illustrates the “” table. The degrees of fire resistance are indicated there, as they correlate well with the materials used in the construction of a residential building.

So what do we see?

Of the most used building materials fall into category A (non-flammable) ceramic tile, brick, stone and concrete, expanded clay and plaster. It is with these materials that the walls of the boiler room should be lined or made from them.

Oak and beech fell into category C1 (poorly combustible). I would like to say that these two burn perfectly. They may not be as easy to light as other types of wood, but oak and beech burn excellently. These are the best types of wood when heating a house with wood; they provide the best calorie content for firewood when you heat a stove or solid fuel boiler.

Felt, yes, does burn rather poorly. But this does not mean that they can be used to wrap pipes or somehow isolate them from fire. Felt is useful only where it is necessary to briefly block the access of oxygen to an open flame and thereby extinguish it. That is why the fire blanket is made of thick felt.

Medium-burning materials of category C2 include all types of wood that are usually used for construction work. These are spruce and pine, the basis for the production of lumber.

They rarely build from larch in the European part of Russia, since here this tree is quite expensive. At a price of conifers up to 6,000 rubles per cubic meter, larch will cost you 10-12 thousand rubles per cubic meter.

Any wooden structures, which are used in your home, in which combustion and open flames are used, as well as from chimneys - this is clearly stated in the Fire Safety Standards.

Highly combustible or flammable materials from category C3, which includes asphalt and bitumen, must be protected even from accidental sparks. That's why they isolate you so much steel chimneys on roofs made of built-up and bituminous materials, and also supply chimneys spark arresters.

And one more thing - expanded polystyrene (EPS) or polystyrene belongs to group C3, that is, it is a highly combustible material. And no tricks of manufacturers to impregnate it with fire retardants will make it a material of category C1 or B, no matter what is written in the advertising brochures.

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 the nomenclature of indicators fire danger fire retardant compounds to determine their scope of application in the construction and finishing 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 fire retardant composition. 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, measure: the temperature of the exhaust flue gases, length of the damaged section of the sample, mass, 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 density heat flow, the value of which is determined by the length of the flame propagation according to the sample, the material treated with a fire retardant composition is assigned 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 flammability group is a 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 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.

Video

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 with an average density of 670 kg/m³ and a thickness of 12.5 mm according to GOST 30403-96 belong to 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, 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 the material characterizes it as having low smoke generating 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.

Flammability is the ability of substances and materials to ignite.

Federal Law No. 123-FZ of July 22, 2008 “ Technical regulations about the requirements fire safety» defines General requirements, which determine the possibility of using construction and finishing materials depending on their flammability rating.

The flammability index is also taken into account when choosing materials for finishing floors, walls and ceilings along escape routes in buildings.

The essence of the method for determining the flammability of a material is to determine the parameters of the flammability of the material at the levels specified by the standard of exposure to the surface of the test sample of radiant heat flux and flame from the ignition source.

The parameters of the flammability of a material are the critical surface heat flux density (CSHDD) and the ignition time.

To classify materials into flammability groups, KPPTP (the minimum value of surface heat flux density at which stable flame combustion occurs) is used.

Combustible building materials (according to GOST 30244), depending on the value of the KPPTP (the minimum value of the surface heat flux density at which stable flaming combustion occurs), are divided into three flammability groups: B1, B2, B3.

To conduct tests at the Federal State Budgetary Institution SEU FPS IPL in the Republic of Mordovia, it is necessary to provide 15 samples square shape, with sides 165 mm and deviation minus 5 mm. The thickness of the samples should be no more than 70 mm. For each value of surface heat flux density (SHHD), tests are carried out on three samples.

When making samples, the exposed surface should not be processed.

If there are corrugations, relief, embossing, etc. on the exposed surface. The size of the protrusions (depressions) should be no more than 5 mm.

If the exposed surface does not meet the specified requirements, it is allowed to make samples for testing from a material with a flat surface, i.e. without corrugations, relief, embossing, etc.

Samples for standard testing of materials used only as finishing and facing materials, as well as for testing paint coatings And roofing materials, are made in combination with a non-flammable base. The fastening method must ensure tight contact between the surfaces of the material and the base.

Should be used as a non-flammable base asbestos cement sheets according to GOST 18124 with a thickness of 10 or 12 mm.

In cases where specific technical documentation does not provide conditions for standard testing, samples are made with the base and fastening specified in the technical documentation.

For layered materials with different surface layers, two sets of samples are made to expose both surfaces. In this case, the flammability group of the material is determined based on the worst result.

Testing of samples is carried out in a thermophysical laboratory at the Flammability testing facility.

Installation diagram for determining the flammability of materials. 1 - radiation panel with heating element; 2 - movable burner; 3 - auxiliary stationary burner; 4 - power cable heating element; 5 - cam with a stroke limiter for manual control of the movable burner; 6 - cam for automatic control of the movable burner; 7 - drive belt; 8 — bushing for connecting the movable burner to the fuel supply system; 9 — mounting plate for the ignition system and the movable burner movement system; 10 — protective plate; 11 — vertical support; 12 — vertical guide; 13 - movable platform for the sample; 14 — base of the support frame; 15 - manual control; 16 — lever with counterweight; 17 - drive to the electric motor.

Installation type “Flammability”

The results are processed according to the GOST 30402-96 methodology. For each tested sample, the ignition time and the following additional observations are recorded: time and place of ignition; process of destruction of a sample under the influence thermal radiation and flame; melting, swelling, delamination, cracking, swelling or shrinkage.

After testing and payment of the test cost, fire testing laboratory employees prepare reporting documentation.

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 specific material– this 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 by themselves cannot burn in air. 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.

Preferred use in construction non-combustible materials, 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.

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. As an example of such additional measures, there can be a floor-by-floor fire-proof cut-off 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.

Main classification building structures according to fire safety classes it looks like this:

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 make external cladding of walls and foundations from 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.