By origin and purpose

Based on their origin, building materials can be divided into two groups: natural and artificial.

Natural These are materials that are found in nature in finished form and can be used in construction without significant processing.

Artificial are called building materials that are not found in nature, but are manufactured using various technological processes.

Based on their intended purpose, building materials are divided into the following groups:

Materials intended for the construction of walls (brick, wood, metals, concrete, reinforced concrete);

Cementing materials (cement, lime, gypsum) used to produce non-fired products, masonry and plaster;

Thermal insulation materials (foam and aerated concrete, felt, mineral wool, foam plastics, etc.);

Finishing and facing materials(stones, ceramic tiles, various types plastics, linoleum, etc.);

Roofing and waterproofing materials (roofing steel, tiles, asbestos-cement sheets, slate, roofing felt, roofing felt, Izol, Brizol, Poroizol, etc.)

NON-COMBUSTABLE BUILDING MATERIALS

Natural stone materials. Natural stone materials are building materials obtained from rocks through the use of only mechanical processing (crushing, sawing, splitting, grinding, etc.). They are used for the construction of walls, flooring, stairs and building foundations, cladding various designs. In addition, rocks are used in the production of artificial stone materials (glass, ceramics, thermal insulation materials), and also as a raw material for the production of binders: gypsum, lime, cement.

The effect of high temperatures on natural stone materials. All natural stone materials used in construction are non-flammable, however, under the influence of high temperatures, various processes occur in stone materials, leading to a decrease in strength and destruction.

The minerals included in stone materials have different coefficients of thermal expansion, which can lead to the appearance of internal stresses in the stone and the appearance of defects in its internal structure.

The material undergoes a modification transformation of the crystal lattice structure associated with an abrupt increase in volume. This process leads to cracking of the monolith and a decrease in the strength of the stone due to large temperature deformations resulting from sudden cooling.

It should be emphasized that all stone materials lose their properties irreversibly when exposed to high temperatures.

Ceramic products. Since all ceramic materials and products in the process of their production are fired at high temperatures, repeated exposure to high temperatures under fire conditions does not have a significant effect on their physical and mechanical properties if these temperatures do not reach the softening (melting) temperatures of the materials. Porous ceramic materials (ordinary clay bricks, etc.), obtained by firing without sintering, can be exposed to moderately high temperatures, as a result of which some shrinkage of structures made from them is possible. The impact of high temperatures during a fire on dense ceramic products, which are fired at temperatures of about 1300 °C, practically does not have any harmful effect, since the temperature during a fire does not exceed the firing temperature.

Red clay brick is the best material for the construction of fire walls.

Metals. In construction, metals are widely used for the construction of frames of industrial and civil buildings in the form of rolled steel profiles. A large amount of steel is used to make reinforcement for reinforced concrete. They use steel and cast iron pipes, roofing steel. IN recent years Lightweight building structures made of aluminum alloys are increasingly used.

Behavior of steels in fire. One of the most characteristic features of all metals - the ability to soften when heated and restore their physical and mechanical properties after cooling. In the event of a fire, metal structures heat up very quickly, lose strength, become deformed and collapse.

Reinforcing steels will behave worse in fire conditions (see section “Reference materials”), which are obtained by additional hardening methods heat treatment or cold broaching (hardening). The reason for this phenomenon is that these steels obtain additional strength due to distortion of the crystal lattice, and under the influence of heating, the crystal lattice returns to an equilibrium state and the increase in strength is lost.

Aluminum alloys. The disadvantage of aluminum alloys is their high coefficient of thermal expansion (2-3 times higher than that of steel). When heated, there is also a sharp decrease in their physical and mechanical properties. The tensile strength and yield strength of aluminum alloys used in construction are reduced by approximately half at temperatures of 235-325 °C. In fire conditions, the temperature in the room volume can reach these values in less than one minute.

Materials and products based on mineral melts and products from glass melts. This group includes: glass materials, products from slag and stone castings, glass glass and slag glass, sheet window and display glass, patterned, reinforced, solar and heat-protective, facing glass, glass profiles, double-glazed windows, glass carpet-mosaic tiles, glass blocks, etc. .

Behavior of materials and products from mineral melts at high temperatures. Materials and products made from mineral melts are non-flammable and cannot contribute to the development of a fire. The exception is materials made on the basis of mineral fibers containing some amount of organic binder, such as thermal insulating mineral boards, silica boards, slabs and rolled mats made of basalt fiber. The flammability of such materials depends on the amount of binder introduced. In this case, its fire hazard will be determined mainly by the properties and amount of polymer in the composition.

Window glass cannot withstand prolonged heat loads during a fire, but with slow heating it may not collapse for quite a long time. The destruction of glass in light openings begins almost immediately after the flame begins to touch its surface.

Structures made from tiles, stones, and blocks made from mineral melts have significantly greater fire resistance than sheet glass, since even after cracking, they continue to bear the load and remain sufficiently impenetrable to combustion products. Porous materials from mineral melts retain their structure almost up to the melting temperature (for foam glass, for example, this temperature is about 850 ° C) and perform heat-protective functions for a long time. Since porous materials have a very low thermal conductivity coefficient, even at the moment when the side facing the fire melts, deeper layers can perform heat-protective functions.

COMBUSTIBLE BUILDING MATERIALS

Wood. When wood is heated to 110 °C, moisture is removed from it, and gaseous products of thermal destruction (decomposition) begin to be released. When heated to 150 °C, the heated surface of the wood turns yellow, and the amount of volatile substances released increases. At 150-250 °C wood acquires brown due to charring, and at 250-300 °C ignition of wood decomposition products occurs. The self-ignition temperature of wood is in the range of 350-450 °C.

Thus, the process of thermal decomposition of wood occurs in two phases: the first phase - decomposition - is observed when heated to 250 ° C (to the ignition temperature) and occurs with the absorption of heat, the second, the combustion process itself, occurs with the release of heat. The second phase, in turn, is divided into two periods: the combustion of gases formed during the thermal decomposition of wood (flame phase of combustion), and the combustion of the resulting charcoal(smoldering phase).

Bitumen and tar materials. Construction materials that contain bitumen or tar are called bitumen or tar.

Ruberoid and tar paper roofs can catch fire even from low-power fire sources, such as sparks, and continue to burn on their own, emitting large number thick black smoke. When burning, bitumen and tar soften and spread, which significantly complicates the situation during a fire.

The most common and in an efficient way Reducing the flammability of roofs made of bitumen and tar materials is to sprinkle them with sand, backfill them with a continuous layer of gravel or slag, and cover them with any non-combustible tiles. Some fire-retardant effect is provided by covering rolled materials with foil - such coatings do not ignite when exposed to sparks.

It should be kept in mind that roll materials, made with the use of bitumen and tar, are prone to spontaneous combustion when rolled up. This circumstance must be taken into account when storing such materials.

Polymer building materials. Polymer building materials (PSM) are classified according to various criteria: type of polymer (polyvinyl chloride, polyethylene, phenol-formaldehyde, etc.), production technology (extrusion, injection molding, roller-calender, etc.), purpose in construction (structural, finishing, flooring materials , heat and sound insulating materials, pipes, sanitary and molded products, mastics and adhesives). All polymer building materials are highly flammable, smoke-generating and toxic.

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

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

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

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

Substances and materials

According to GOST 12.1.044-89, according to flammability, substances and materials are divided into the following groups ( excluding construction, textile and leather materials):

Non-flammable.
Low-flammability.
Flammable.

Non-flammable – these are substances and materials that are unable to burn in air. Non-flammable substances can be fire-explosive (for example, oxidizers or substances that release flammable products when interacting with water, atmospheric oxygen, or with each other).

Low-flammability – these are substances and materials that can burn in air when exposed to an ignition source, but are unable to burn independently after it is removed.

Flammable – these are substances and materials that can spontaneously ignite, as well as ignite when exposed to an ignition source and burn independently after its removal.

Essence experimental method Determining flammability consists of creating temperature conditions conducive to combustion and assessing the behavior of the substances and materials under study under these conditions.

Solid (including dust)

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

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

Based on the value of the maximum temperature increase (Δt max) and mass loss (Δm), materials are classified:

flame retardant: Δt max< 60 °С и Δm < 60%;
flammable: Δt max ≥ 60 °C or Δm ≥ 60%.

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

hardly flammable: τ > 4 min;
average flammability: 0.5 ≤ τ ≤ 4 min;
flammable: τ< 0,5 мин.

Gases

If there are concentration limits for flame propagation, the gas is classified as flammable ; in the absence of concentration limits for flame propagation and the presence of a self-ignition temperature, the gas is classified as flame retardant ; in the absence of concentration limits for flame propagation and auto-ignition temperature, the gas is classified as non-flammable .

Liquids

If there is an ignition temperature, the liquid is classified as flammable ; in the absence of an ignition temperature and the presence of a self-ignition temperature, the liquid is classified as flame retardant . In the absence of flash points, ignition, self-ignition, temperature and concentration limits for flame propagation, the liquid is classified as non-flammable . Flammable liquids with a flash point of not more than 61 ° C in a closed crucible or 66 ° C in an open crucible, phlegmatized mixtures that do not have a flash in a closed crucible are classified as flammable . Particularly dangerous These are flammable liquids with a flash point of no more than 28 °C.

Classification of building materials

Determination of the flammability group of a building material

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

The ability to spread flame over a surface.
Smoke generating ability.
Toxicity of combustion products.

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

NG (non-flammable)

Based on test results using methods I and IV (), non-combustible building materials are divided into 2 groups.

Construction materials are classified as non-combustible group I

temperature increase in the oven no more than 30 °C;
duration of stable flame combustion – 0 s;
calorific value not more than 2.0 MJ/kg.

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

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

Allowed to be classified as non-flammable of group I without testing the following building materials without painting their external surface or with painting the external surface with compositions without the use of polymer and (or) organic components:

concrete, mortars, plasters, adhesives and putties, clay, ceramic, porcelain stoneware and silicate products (bricks, stones, blocks, slabs, panels, etc.), fiber cement products (sheets, panels, slabs, pipes, etc.) with the exception of in all cases of materials manufactured using polymer and (or) organic binder fillers and fiber;
inorganic glass products;
products made from alloys of steel, copper and aluminum.

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

Combustible building materials, depending on the values of flammability parameters determined by method II, are divided into four flammability groups (G1, G2, G3, G4) in accordance with the table. Materials should be classified into a certain flammability group provided that all arithmetic mean values of the parameters specified in the table for this group correspond.

G1 (low flammability)

Low flammable – these are materials with a flue gas temperature of no more than 135 °C, the degree of damage along the length of the test sample is not more than 65%, the degree of damage along the mass of the test sample is not more than 20%, and the duration of spontaneous combustion is 0 seconds.

G2 (moderately flammable)

Moderately flammable – these are materials with a flue gas temperature of no more than 235 °C, the degree of damage along the length of the test sample is no more than 85%, the degree of damage along the mass of the test sample is no more than 50%, and the duration of independent combustion is no more than 30 seconds.

G3 (normally flammable)

Normally flammable – these are materials with a flue gas temperature of no more than 450 °C, a degree of damage along the length of the test sample of more than 85%, a degree of damage along the mass of the test sample of no more than 50%, and a duration of independent combustion of no more than 300 seconds.

G4 (highly flammable)

Highly flammable – these are materials with a flue gas temperature of more than 450 °C, a degree of damage along the length of the test sample of more than 85%, a degree of damage along the mass of the test sample of more than 50%, and a duration of independent combustion of more than 300 seconds.

Table

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

Video, what is a flammability group

Sources: ; Baratov A.N. Combustion – Fire – Explosion – Safety. -M.: 2003; GOST 12.1.044-89 (ISO 4589-84) System of occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination; GOST R 57270-2016 Construction materials. Combustibility test methods.

The fact is that the deformation of a non-combustible material can be no less dangerous than the ability to ignite, and the abundant formation of soot causes the same harm as the release of toxic substances. But progress does not stand still and hundreds of chemical, structural and other ways have been invented to improve the properties of construction products, including in the context fire safety. Those materials that were recently considered dangerous have ceased to be so, but this does not mean that this characteristic can be ignored when building a house. In the end, no one is immune from accidents, and minimizing possible damage from fire is the direct responsibility of the homeowner.

Terminology

Speaking about construction from the point of view of exposure to fire and high temperatures, it is necessary to highlight two concepts - fire resistance and fire safety.

Fire resistance as a term refers not to materials, but to building structures and characterizes their ability to resist the effects of fire without loss of strength and load-bearing capacity. This parameter is discussed in the context of the thickness of the structure and the time that must pass before it loses its strength properties. For example, the phrase “the fire resistance limit of partitions made of 120 mm thick porous ceramic blocks was EI60” means that they can resist fire for 60 minutes.

Fire safety characterizes building materials and describes their behavior under the influence of fire. That is, it means flammability, flammability, ability to spread flame over a surface and smoke formation, toxicity of combustion products. For each quality, materials are tested in laboratory conditions and assigned a certain class, which will be noted in the product labeling.

By flammability distinguish non-flammable (NG) and flammable (G1, G2, G3, and G4) materials, where G1 is slightly flammable, and G4 is highly flammable. Products of the NG class are not classified, so the remaining classes apply only to flammable products.
By flammability- from B1 (lowly flammable) to B3 (highly flammable).
By toxicity- from T1 (low-risk) to T4 (extremely dangerous).
According to smoke-forming ability- from D1 (weak smoke production) to D3 (strong smoke production).
Ability to spread flame over a surface- from RP-1 (not spreading flame) to RP-4 (highly spreading).

Since the issues of product classification are being resolved in Ukraine, not every building material is labeled according to all of the above indicators. However, you can always check the class with the seller and review the test results by requesting the appropriate protocols.

Concrete and cellular concrete

Plain concrete belongs to the class non-combustible materials. It perfectly tolerates temperatures up to 250-300 °C for 2-5 hours, but at temperatures above 300 °C irreversible changes occur in the material. Loss of strength and cracking This is facilitated by the metal reinforcement located inside the blocks, so reinforced concrete structures resist fire much worse than concrete ones. Another factor leading to loss of strength is Portland cement, which is included in some concretes. But lean concrete with a low cement content and a high content of fillers, which is often used to construct floors on the ground, resists fire better. More durable is lightweight concrete with a volumetric mass of less than 1800 kg/m³. And yet, despite some disadvantages, there are qualities that make concrete an attractive material from a fire safety point of view. Its heating rate is low, it has low thermal conductivity, and a significant part of the heat when heated will be spent on evaporating the water included in the composition and absorbed from the surrounding space, which will save time for evacuation. In addition, concrete resists short-term exposure to high temperatures well.

Cellular concrete also belongs to the class of non-combustible. The characteristics of this material may vary from manufacturer to manufacturer. But in general, it is able to withstand exposure to high temperatures (up to 300 °C) for 3-4 hours, as well as short-term very high temperatures (more than 700 °C). This material does not emit toxic fumes. However, it must be taken into account that although cellular concrete does not collapse, it can shrink quite significantly and become covered with cracks. Therefore, when deciding to restore a house, you need to check bearing capacity structures by inviting a specialist builder. In some cases, even after a fire with the collapse of a wooden truss structure, walls made of cellular concrete can be restored.

Ceramic bricks and porous blocks

Ceramic masonry materials belong to the non-combustible class. High temperatures(up to 300 °C) blocks and bricks can withstand for 3-5 hours. The fire resistance of materials depends quite strongly on the quality of the clay used in their manufacture and the firing conditions: various natural impurities can significantly worsen the fire resistance indicators. In addition, it must be taken into account that voids in the material contribute to better spread of fire, therefore solid brick more resistant to fires than hollow and porous ceramic blocks.

High temperatures make ceramic wall materials more fragile and hygroscopic. Metal fasteners and other metal elements under the influence of fire also reduce the strength of the material: cracks and breaks occur at the fastening site. In general, ceramic walls are easy to restore and refinish, but only with the permission of specialists who can determine the places where the loss of strength has occurred. Clay practically does not accumulate odors, so the likelihood is that after restoration in a house from ceramic bricks or blocks there will be a burning smell, minimal.

Read also: Wood that doesn't burn: wood fire protection

Wood

The fire hazard of wood is due to the fact that it has both increased flammability and high combustibility. This material and structures made from it without special protective measures have a flammability group of G4, flammability of B3, flame propagation of RP3 and RP4, smoke generation of D2 and D3 and toxicity of T3. Special fire protection techniques can significantly improve all these indicators. They can be divided into three groups: constructive methods, surface application of special fire-fighting compounds and deep impregnation with fire retardants.

Constructive methods include plastering wooden surfaces, coating with fire-retardant elements, non-combustible cladding (in particular plasterboard, asbestos-cement or magnesite boards), increasing the cross-section wooden structures, grinding the surface of beams and timber, as a result of which the fire slides along the surface without destroying the structure of the material.

When applying special compounds to the surface, brushes, rollers or a spray gun are used, but it must be remembered that in this case the penetration of the composition deep into the material will be insignificant and surface impregnation can only be considered as a method of additional protection.

The main method remains autoclave treatment with fire retardants under pressure, which can only be carried out in production.

Using these methods, it is possible to reduce the flammability of wood to G2 and even G1 and, accordingly, improve performance in all other classes.

“Sandwich” panels cannot be called a material, since it is a structure made of wood OSB and polystyrene foam. But from a construction point of view, they can still be considered a wall building material. Both OSB and expanded polystyrene, which are part of the panels, are themselves flammable, but given that fire usually occurs in the premises of the house, the danger of SIP is greatly exaggerated, since the inside of the product is lined with non-flammable plasterboard sheets. On the outside, they are often finished with siding having a flammability class of G1 or G2, or with non-flammable plaster. And polystyrene foam itself is treated with fire retardants, so the entire wall structure has good fire safety performance.

GOST 30244-94

INTERSTATE STANDARD

CONSTRUCTION MATERIALS

FLAMMABILITY TEST METHODS

INTERSTATE SCIENTIFIC AND TECHNICAL COMMISSION
ON STANDARDIZATION AND TECHNICAL REGULATION
IN CONSTRUCTION (MNTKS)

Moscow

Preface

1 DEVELOPED by the State Central Research and Design and Experimental Institute of Complex Problems building structures and buildings named after V.A. Kucherenko (TsNIISK named after Kucherenko) and the Center for Fire Research and Thermal Protection in Construction TsNIISK (TsPITS TsNIISK) of the Russian Federation

INTRODUCED by the Ministry of Construction of Russia

2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (INTKS) on November 10, 1993.

State name	Name of the state construction management body
Azerbaijan Republic	State Construction Committee of the Azerbaijan Republic
Republic of Armenia	State Architecture of the Republic of Armenia
Republic of Belarus	Ministry of Construction and Architecture of the Republic of Belarus
Republic of Kazakhstan	Ministry of Construction of the Republic of Kazakhstan
Kyrgyz Republic	Gosstroy of the Kyrgyz Republic
Republic of Moldova	Ministry of Architecture and Construction of the Republic of Moldova
Russian Federation	Ministry of Construction of Russia
Republic of Tajikistan	State Construction Committee of the Republic of Tajikistan
Republic of Uzbekistan	State Committee for Architecture and Construction of the Republic of Uzbekistan
Ukraine	State Committee for Urban Development of Ukraine

3 Clause 6 of this standard is the authentic text of ISO 1182-80 Fire tests - Building matrifles - Non-combustibility test Fire tests. - Construction materials. - Non-flammability test" (Third edition 1990-12-01).

4 ENTERED INTO EFFECT on January 1, 1996 as a state standard of the Russian Federation by Resolution of the Ministry of Construction of Russia dated August 4, 1995 No. 18-79

5 INSTEAD ST SEV 382-76, ST SEV 2437-80

INTERSTATE STANDARD

CONSTRUCTION MATERIALS

Flammability Test Methods

Building materials.

Methods for combustibility test

Date of introduction 1996-01-01

1 AREA OF APPLICATION

This standard establishes methods for testing building materials for flammability and their classification into flammability groups.

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

2 REGULATORY REFERENCES

6.3.5 The tubular furnace is installed in the center of a casing filled with insulating material (outer diameter 200 mm, height 150 mm, wall thickness 10 mm). The upper and lower parts of the casing are limited by plates that have recesses on the inside for fixing the ends of the tubular furnace. The space between the tube furnace and the walls of the casing is filled with powdered magnesium oxide with a density of (140±20) kg/m3.

6.3.6 The lower part of the tube furnace is connected to a cone-shaped air flow stabilizer 500 mm long. The internal diameter of the stabilizer should be (75±1) mm in the upper part, (10±0.5) mm in the lower part. The stabilizer is made of sheet steel 1 mm thick. The inner surface of the stabilizer must be polished. The seam between the stabilizer and the furnace should be pressed tightly to ensure tightness and carefully processed to eliminate roughness. The upper half of the stabilizer is insulated from the outside with a layer of mineral fiber 25 mm thick [thermal conductivity (0.04 ± 0.01) W/(m × K) at 20 ° WITH].

6.3.7 The upper part of the furnace is equipped with a protective screen made of the same material as the stabilizer cone. The screen height should be 50 mm, internal diameter (75±1) mm. The inner surface of the screen and the connecting seam with the furnace are carefully processed until a smooth surface is obtained. The outer part is insulated with a layer of mineral fiber 25 mm thick [thermal conductivity (0.04±0.01) W/(m × K) at 20 °C].

6.3.8 The block, consisting of a furnace, a cone-shaped stabilizer and a protective screen, is mounted on a frame equipped with a base and a screen to protect the lower part of the cone-shaped stabilizer from directed air flows. The height of the protective screen is approximately 550 mm, the distance from the bottom of the cone-shaped stabilizer to the base of the frame is approximately 250 mm.

6.3.9 To observe the flaming combustion of the sample, a mirror with an area of 300 mm 2 is installed above the furnace at a distance of 1 m at an angle of 30 °C.

6.3.10 The installation should be placed so that directed air flows or intense solar and other types of light radiation do not affect the observation of the flaming combustion of the sample in the furnace.

6.3.18 Temperature is recorded throughout the experiment using appropriate instruments.

A schematic electrical diagram of the installation with measuring instruments is shown on.

6.4 Preparing the installation for testing

6.4.1 Remove the sample holder from the oven. The furnace thermocouple must be installed in accordance with.

Note- The operations described in - should be carried out during commissioning new installation or when replacing a chimney pipe, heating element, thermal insulation, power supply.

6.5Carrying out the test

6.5.1 Remove the sample holder from the furnace, check the installation of the furnace thermocouple, and turn on the power source.

6.5.2 Stabilize the oven in accordance with.

6.5.3 Place the sample in the holder, install thermocouples in the center and on the surface of the sample in accordance with -.

6.5.4 Insert the sample holder into the oven and position it in accordance with. The duration of the operation should be no more than 5 s.

6.5.5 Start the stopwatch immediately after introducing the sample into the oven. During the test, record the readings of thermocouples in the furnace, in the center and on the surface of the sample.

6.5.6 The duration of the test is, as a rule, 30 minutes. The test is stopped after 30 minutes provided that temperature balance has been achieved by this time. Temperature balance is considered achieved if the readings of each of the three thermocouples change by no more than 2 ° C in 10 min. In this case, the final thermocouples are fixed in the furnace, in the center and on the surface of the sample.

If, after 30 minutes, temperature balance is not achieved for at least one of the three thermocouples, the test is continued, checking for temperature balance at 5-minute intervals.

6.5.7 When temperature balance is achieved for all three thermocouples, the test is stopped and its duration is recorded.

6.5.8 The sample holder is removed from the oven, the sample is cooled in a desiccator and weighed.

Residues that fall off the sample during or after testing (carbonation products, ash, etc.) are collected, weighed and included in the mass of the sample after the test.

Photos of samples after testing;

Conclusion based on test results indicating what type of material it is: flammable or non-flammable;

Duration of the conclusion.

7 METHOD FOR TESTING COMBUSTIBLE BUILDING MATERIALS TO DETERMINE THEIR FLAMMABILITY GROUPS

Method II

7.1 Scope of application

The method is used for all homogeneous and layered combustible building materials, including those used as finishing and facing, as well as paint and varnish coatings.

7.2 Samples for testing

7.3.2 The design of the walls of the combustion chamber must ensure stability temperature regime tests established by this standard. For this purpose, it is recommended to use the following materials:

For the internal and external surfaces of the walls - sheet steel 1.5 mm thick;

For the thermal insulation layer - mineral wool slabs[density 100 kg/m 3, thermal conductivity 0.1 W/(m × K), thickness 40 mm].

7.3.3 A sample holder, ignition source, and diaphragm are installed in the combustion chamber. The front wall of the combustion chamber is equipped with a door with glazed openings. A hole with a plug for inserting thermocouples should be provided in the center of the side wall of the chamber.

7.3.4 The sample holder consists of four rectangular frames located around the perimeter of the ignition source (), and must ensure, as shown in the position of the sample relative to the ignition source, the stability of the position of each of the four samples until the end of the test. The sample holder should be installed on support frame, ensuring its free movement in the horizontal plane. The sample holder and fastening parts should not overlap the sides of the exposed surface by more than 5 mm.

7.3.5 The ignition source is gas burner, consisting of four separate segments. Mixing of gas with air is carried out using holes located on the gas supply pipes at the entrance to the segment. The location of the burner segments relative to the sample and its circuit diagram shown on .

7.3.6 The air supply system consists of a fan, rotameter and diaphragm, and must ensure that bottom part combustion chamber with an air flow evenly distributed over its cross section in the amount of (10±1.0) m 3 /min at a temperature of at least (20 ± 2) °C.

7.3.7 The diaphragm is made of perforated steel sheet 1.5 mm thick with holes with diameters of (20 ± 0.2) mm and (25 ± 0.2) mm and located above it at a distance of (10 ± 2) mm metal mesh from wire with a diameter of no more than 1.2 mm with a mesh size of no more than 1.5 ´ 1.5 mm. The distance between the diaphragm and the upper plane of the burner must be at least 250 mm.

7.3.9 The ventilation system for removing combustion products consists of an hood installed above the exhaust pipe, an air duct and a ventilation pump.

7.3.10 To measure temperature during testing, thermocouples with a diameter of no more than 1.5 mm and corresponding recording instruments are used.

7.4 Preparing for the test

7.4.1 Preparation for testing consists of carrying out calibration in order to establish the gas flow rate (l/min) that ensures the test temperature conditions established by this standard in the combustion chamber (Table 3).

Insert the holder with the sample into the combustion chamber, turn on measuring instruments, air supply, exhaust ventilation, ignition source, close the door, record the thermocouple readings 10 minutes after turning on the ignition source.

If the temperature in the combustion chamber does not meet the requirements, repeat the calibration at other gas flow rates.

The gas flow rate established during calibration should be used during testing until the next calibration.

7.5 Carrying out the test

7.5.1 Three tests should be carried out for each material. Each of the three tests consists of simultaneous testing of four material samples.

7.5.2 Check the flue gas temperature measurement system by turning on the measuring instruments and the air supply. This operation is carried out with the combustion chamber door closed and the ignition source inoperative. The deviation of the readings of each of the four thermocouples from their arithmetic mean value should be no more than 5 ° WITH.

7.5.3 Weigh four samples, place them in the holder, and introduce it into the combustion chamber.

7.5.4 Turn on the measuring instruments, air supply, exhaust ventilation, ignition source, close the chamber door.

7.5.5 The duration of exposure of the sample to flame from the ignition source should be 10 minutes. After 10 minutes, the ignition source is turned off. If there is a flame or signs of smoldering, the duration of spontaneous combustion (smoldering) is recorded. The test is considered complete after the samples have cooled to ambient temperature.

7.5.6 After completing the test, turn off the air supply, exhaust ventilation, and measuring instruments, and remove samples from the combustion chamber.

7.5.7 For each test, the following indicators are determined:

Flue gas temperature;

Duration of independent combustion and (or) smoldering;

Length of damage to the sample;

Mass of the sample before and after testing.

7.5.8 During the test, the temperature of the flue gases is recorded at least twice per minute according to the readings of all four thermocouples installed in the gas outlet pipe, and the duration of spontaneous combustion of the samples is recorded (in the presence of a flame or signs of smoldering).

7.5.9 During testing, the following observations are also recorded:

Time to reach maximum flue gas temperature;

Transfer of flame to the ends and unheated surface of the samples;

Through burning of samples;

Formation of a burning melt;

Appearance of samples after testing: soot deposition, color change, melting, sintering, shrinkage, swelling, warping, cracking, etc.;

Time until flame spreads along the entire length of the sample;

Duration of combustion along the entire length of the sample.

7.6 Processing test results

7.6.1 After completion of the test, measure the length of the segments of the undamaged part of the samples (along ) and determine the residual mass t to samples.

The part of the sample that is not burned or charred either on the surface or inside is considered intact. Soot deposition, change in sample color, local chipping, sintering, melting, swelling, shrinkage, warping, change in surface roughness are not considered damage.

The measurement result is rounded to the nearest 1 cm.

The undamaged part of the samples remaining on the holder is weighed. The weighing accuracy must be at least 1% of the initial mass of the sample.

7.6.2 Processing the results of one test (four samples)

7.6.2.1 Flue gas temperature T i is taken equal to the arithmetic mean of the simultaneously recorded maximum temperature readings of all four thermocouples installed in the gas outlet pipe.

7.6.2.2 The length of damage to one sample is determined by the difference between the nominal length before testing (according to ) and the arithmetic mean length of the undamaged part of the sample, determined from the lengths of its segments, measured in accordance with

The measured lengths of the segments should be rounded to 1 cm.

7.6.2.3 The length of damage to samples during testing is determined as the arithmetic mean of the damage lengths of each of the four tested samples.

7.6.2.4 Damage by mass of each sample is determined by the difference between the mass of the sample before testing and its residual mass after testing.

7.6.2.5 Damage by mass of samples is determined by the arithmetic average value of this damage for four tested samples.

7.7 Test report

7.7.1 The test report provides the following data:

Test date;

Name of the laboratory conducting the test;

Customer's name;

Name of material;

Code of technical documentation for the material;

Description of the material indicating the composition, manufacturing method and other characteristics;

The name of each material that is integral part layered material, indicating the layer thickness;

Method of making a sample, indicating the base material and method of fastening;

Additional observations during testing;

Characteristics of the exposed surface;

Test results (flammability parameters according to);

Photo of the sample after testing;

Conclusion based on test results on the flammability group of the material.

For materials tested in accordance with and, indicate the flammability groups for all cases established by these paragraphs;

Duration of the conclusion.

APPENDIX A

(required)

INSTALLATION FOR TESTING BUILDING MATERIALS FOR NON-COMBUSTIBILITY (method - thermocouple in the center of the sample;T s - thermocouple on the surface of the sample; 1 - stainless steel tube; 2 - mesh (mesh size 0.9 mm, wire diameter 0.4 mm)

Figure A3 - Sample holder

1 - wooden handle; 2 - weld

T f- furnace thermocouple; T S - thermocouple in the center of the sample;T s - thermocouple on the surface of the sample; 1 - furnace wall; 2 - mid-height of the constant temperature zone; 3 - thermocouples in a protective casing; 4 - contact of thermocouples with material

Figure A5 - Relative position of the furnace, sample and thermocouples

, flammability , test methods , classification by flammability groups

Based on flammability, substances and materials are divided into three groups: non-flammable, slow-burning and flammable.

Non-flammable (hard to burn) - substances and materials that are not capable of burning in air. Non-flammable substances can be fire and explosion hazards.

Low-flammability (hard-to-burn) - substances and materials capable of burning in air when exposed to an ignition source, but not capable of burning independently after its removal.

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

All flammable substances are divided into the following main groups:

Combustible gases (GG) - substances capable of forming flammable and explosive mixtures with air at temperatures not exceeding 50° C. Flammable gases include individual substances: ammonia, acetylene, butadiene, butane, butyl acetate, hydrogen, vinyl chloride, isobutane, isobutylene, methane, carbon monoxide, propane, propylene, hydrogen sulfide, formaldehyde, as well as vapors of flammable and combustible liquids.

Flammable liquids (flammable liquids) - substances capable of burning independently after removal of the ignition source and having a flash point not higher than 61 ° C (in a closed crucible) or 66 ° (in an open crucible). These liquids include individual substances: acetone, benzene, hexane, heptane, dimethylforamide, difluorodichloromethane, isopentane, isopropylbenzene, xylene, methyl alcohol, carbon disulfide, styrene, acetic acid, chlorobenzene, cyclohexane, ethyl acetate, ethylbenzene, ethyl alcohol, as well as mixtures and technical products gasoline, diesel fuel, kerosene, white alcohol, solvents.

Flammable liquids (FL) - substances capable of burning independently after removal of the ignition source and having a flash point above 61° (in a closed crucible) or 66° C (in an open crucible). Flammable liquids include the following individual substances: aniline, hexadecane, hexyl alcohol, glycerin, ethylene glycol, as well as mixtures and technical products, for example, oils: transformer oil, vaseline, castor oil.

Combustible dust(/77) - solid substances in a finely dispersed state. Combustible dust in the air (aerosol) is capable of forming explosive

3 Classification of premises according to fire safety

In accordance with the “All-Union Standards of Technological Design” (1995), buildings and structures in which production is located are divided into five categories (Table 5).

	Characteristics of substances and materials located (circulating) in the room
explosion-hazardous	Combustible gases, flammable liquids with a flash point of not more than 28 ° C in such quantities that they can form explosive vapor-gas-air mixtures, the ignition of which creates a calculated excess explosion pressure in the room exceeding 5 kPa. Substances and materials capable of exploding and burning when interacting with water, air oxygen, or one with the other in such quantities that the calculated excess explosion pressure in the room exceeds 5 kPa.
explosion and fire hazard	Combustible dusts or fibers, flammable liquids with a flash point of more than 28 ° C, flammable liquids in such quantities that they can form explosive dust or steam-air mixtures, the ignition of which develops a calculated excess explosion pressure in the room exceeding 5 kPa.
fire hazardous	Flammable and low-flammable liquids, solid flammable and low-flammable substances and materials that can only burn when interacting with water, air oxygen or one another, provided that the premises in which they are available or handled do not belong to categories A or B
	Non-combustible substances and materials in a hot, incandescent or molten state, the processing of which is accompanied by the release of radiant heat, sparks and flames, flammable gases, liquids and solids that are burned or disposed of as fuel
	Non-combustible substances and materials in a cold state

Category A: shops for the processing and use of metallic sodium and potassium, oil refining and chemical production, warehouses for gasoline and cylinders for flammable gases, premises for stationary acid and alkaline battery installations, hydrogen stations, etc.