The division of substances into groups according to the degree of flammability. Classification of building materials for fire hazard Materials d2

To determine the likelihood of a flame, the combustibility of substances and various materials is of primary importance. This characteristic determines the category of fire hazard of structures, premises, industries; allows you to choose the right means to eliminate foci.

The combustibility group of all the material components of the object determines the success of the fire fighting, minimizes the likelihood of casualties.

Features of various substances

It is known that substances can be in different states of aggregation, which are important to take into account when determining the flammability group. GOST provides for a classification based on quantitative indicators.

If the substance can burn, the combustibility group G1 is the most optimal for fire safety than G3 or G4.

Combustibility is of great importance for finishing, heat-insulating, building materials. Based on it, the fire hazard class is determined. So, drywall sheets have a flammability group G1, stone wool - NG (does not burn), and expanded polystyrene is insulated with a flammability group G4, and the use of plaster helps to reduce its fire hazard.

Gaseous substances

Determining the flammability class of gases and liquids, the standards introduce such a concept as the concentration limit. By definition, this is the limiting concentration of a gas in a mixture with an oxidizing agent (air, for example), at which a flame can spread from the ignition point to any distance.

If such a boundary value does not exist, and the gas cannot spontaneously ignite, then it is called non-combustible.

Liquid

Liquids are called combustible if there is a temperature at which they can ignite. If the liquid ceases to burn in the absence of an external source of heating, then it is called slow-burning. Non-flammable liquids do not ignite at all in an air atmosphere under normal conditions.

Some liquids (acetone, ether) may flare at 28℃ and below. They are considered especially dangerous. Flammable liquids at 61 ... 66 ℃ and above are classified as flammable (kerosene, white spirit). Tests are carried out in open and closed crucible.

Solid

In the field of construction, the most relevant is the determination of the combustibility group of solid materials. It is preferable to use substances of the flammability group G1 or NG, as the most resistant to ignition.

Classification

The intensity of the combustion process and the conditions of its course determine the probability of intensifying the fire, the occurrence of an explosion. The outcome of the incident depends on the totality of the properties of the feedstock.

General division

According to the national standard of fire and explosion hazard, substances and various materials from them are divided into the following groups:

• absolutely non-combustible;
• difficult to burn;
• combustible.

They cannot burn in air, which does not exclude interaction with oxidizing agents, with each other, with water. Consequently, some members of the group under certain conditions represent a fire hazard.

Hard-to-combustible compounds are compounds that burn when ignited in air. As soon as the source of fire is eliminated, combustion stops.

Combustible substances under certain conditions ignite themselves or in the presence of a source of fire, continue to burn intensively.

Classification by combustibility of building raw materials and products is considered in a separate updated standard. Building national standards take into account the categories of all types of products used in the work.

According to this classification, non-combustible building materials (NC) are divided into two groups depending on the test mode and the values ​​of the indicators obtained in this case.

Group 1 includes products, in the study of which the temperature inside the furnace increases by no more than 50 ℃. The sample weight reduction does not exceed 50%. The flame does not burn at all, and the released heat does not exceed 2.0 MJ/kg.

Group 2 NG includes materials with the same indicators of temperature increase inside the furnace and weight loss. The difference is that the flame burns up to 20 seconds, the calorific value should not be more than 3.0 MJ / kg.

Flammability classes

Combustible materials are examined according to similar criteria, divided into 4 groups or classes, which are denoted by the letter G and the number next to it. For classification, the values ​​of the following indicators are taken into account:

• temperature of gases emitted with smoke;
• degree of size reduction;
• amount of weight reduction;
• flame retention time without a combustion source.

G1 refers to a group of materials with a smoke temperature not exceeding 135 ℃. Loss of length fits into 65%, weight - 20%. The flame itself does not burn. Such building products are called self-extinguishing.

G2 includes a group of materials with a smoke temperature not exceeding 235 ℃. Loss of length fits into 85%, mass - 50%. Self-burning lasts no more than 30 seconds.

G3 refers to materials whose smoke temperature does not exceed 450 ℃. Loss of length is more than 85%, weight - up to half. The flame itself burns no more than 300 seconds.

The combustibility group G4 includes materials whose smoke temperature exceeds 450 °C. Loss of length exceeds 85%, weight loss - more than 50%. Self-burning continues for more than 300 seconds.

It is permissible to use the following prefixes in the name of each flammability group in order of increasing numerical index:

• weak;
• moderately;
• fine;
• highly combustible materials.

The given flammability indicators, along with some other characteristics, must be taken into account when developing project documentation and preparing estimates.

The ability to form smoke, the toxicity of combustion products, the rate of possible spread of fire, and the likelihood of rapid ignition are also of great importance.

Class Confirmation

Samples of materials are tested in laboratories and in open areas according to standard methods separately for non-combustible and combustible building materials.

If the product consists of several layers, the standard provides for a test for combustibility of each layer.

Flammability determinations are carried out on special equipment. If it turns out that one of the components has a high flammability, then this status will be assigned to the product as a whole.

The installation for carrying out experimental determinations should be located in a room with room temperature, normal humidity, and without drafts. Bright sunlight or artificial light in the laboratory should not interfere with readings from displays.

Before starting the study of the sample, the device is checked, calibrated, warmed up. Then the sample is fixed in the holder of the inner cavity of the furnace and the recorders are immediately turned on.

The main thing is that no more than 5 seconds have passed since the sample was placed. The determination is continued until a temperature balance is reached, at which the changes do not exceed 2 °C within 10 minutes.

At the end of the procedure, the sample together with the holder is removed from the oven, cooled in a desiccator, weighed and measured, classifying them as flammability groups NG, G1, and so on.

Flammability test method

All building materials, including finishing, facing, paint and varnish types of coatings, regardless of homogeneity or multi-layer, are examined for combustibility by a single method.

Pre-prepare 12 units of identical samples with a thickness equal to the actual values ​​during operation. If the structure is layered, samples are taken from each surface.

Then the samples are kept at room temperature and normal ambient humidity for at least 72 hours, periodically weighed. Holding should be terminated when constant weight is reached.

The unit has a standard design and consists of a combustion chamber, an air supply system and an exhaust gas exhaust system.

Samples are placed in turn into the chamber, measurements are taken, weight loss, temperature and amount of evolved gaseous products, burning time without a flame source are recorded.

Analyzing all the obtained indicators, determine the level of combustibility of the material, its belonging to a certain group.

Application in construction

During the construction of buildings, several different types of building materials are used: structural, insulating, roofing, finishing with different purposes and loads. Certificates must be available for all products and presented to potential buyers.

You should familiarize yourself with the parameters that characterize security in advance, know for sure what each abbreviation and numbers can mean. The law requires that only materials of the combustibility group G1 or NG be used for building ceiling frames.

GOST 30244-94

Group G19

INTERSTATE STANDARD

BUILDING MATERIALS

Flammability test methods

building materials. Methods for combustibility test

ISS 13.220.50
91.100.01
OKSTU 5719

Introduction date 1996-01-01

FOREWORD

FOREWORD

1 DEVELOPED by the State Central Research and Design and Experimental Institute for Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after Kucherenko) and the Center for Fire Research and Thermal Protection in Construction TsNIISK (TsPITZS 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 (MNTKS) on November 10, 1993

Voted to accept:

3 Clause 6 of this International Standard is the authentic text of ISO 1182-80* Fire tests - Building materials - Non-combustibility tests - Construction Materials. - Test for incombustibility (Third Edition 1990-12-01).
________________
* Access to international and foreign documents mentioned in the text can be obtained by contacting the User Support Service. - Database manufacturer's note.

4 ENTERED INTO EFFECT on January 1, 1996 as the state standard of the Russian Federation by Decree of the Ministry of Construction of Russia of August 4, 1995 N 18-79

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

6 REVISION. January 2006

1 area of ​​use

This standard establishes methods for testing building materials for combustibility and classifying them into combustibility groups.

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

2 Normative references

This standard uses references to the following standards:

GOST 12.1.033-81 Occupational safety standards system. Fire safety. Terms and Definitions

GOST 18124-95 Flat asbestos-cement sheets. Specifications

3 Definitions

This standard uses the terms and definitions in accordance with GOST 12.1.033, as well as the following terms.

sustainable flame burning: Continuous flame burning of the material for at least 5 s.

exposed surface: The surface of the specimen exposed to heat and/or open flame during the combustibility test.

4 Fundamentals

4.1 Test Method I (Section 6) is intended to classify building materials as non-combustible or combustible.

4.2 Test Method II (Section 7) is intended for testing combustible building materials in order to determine their combustibility groups.

5 Classification of building materials by flammability groups

5.1 Building materials, depending on the values ​​of the combustibility parameters determined by method I, are divided into non-combustible (NG) and combustible (G).

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

- temperature increase in the furnace is not more than 50°С;

- weight loss of the sample is not more than 50%;

- the duration of stable flame burning is not more than 10 s.

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

5.3 Combustible building materials, depending on the values ​​of the combustibility parameters determined by method II, are divided into four combustibility groups: G1, G2, G3, G4 in accordance with Table 1. Materials should be assigned to a certain combustibility group, provided that all values ​​of the parameters established by table 1 for this group.

Table 1 - Combustibility groups

6 Flammability test method for classifying building materials as non-combustible or combustible

Method I

6.1 Scope

The method is used for homogeneous building materials.

For laminated materials, the method can be used as an estimate. In this case, the tests are carried out for each layer constituting the material.

Homogeneous materials - materials consisting of one substance or an evenly distributed mixture of different substances (for example, wood, foam plastics, polystyrene concrete, particle boards).

Laminated materials - materials made from two or more layers of homogeneous materials (for example, gypsum boards, paper-laminated plastics, homogeneous materials with flame retardant treatment).

6.2 Test pieces

6.2.1 For each test, five cylindrical specimens are made of the following dimensions: diameter mm, height (50 ± 3) mm.

6.2.2 If the thickness of the material is less than 50 mm, the specimens are made from an appropriate number of layers to provide the required thickness. In order to prevent the formation of air gaps between them, the layers of material are tightly connected using thin steel wire with a maximum diameter of 0.5 mm.

6.2.3 In the upper part of the sample, a hole with a diameter of 2 mm should be provided for installing a thermocouple in the geometric center of the sample.

6.2.4 The samples are conditioned in a ventilated oven at a temperature of (60 ± 5) ° C for 20-24 hours, after which they are cooled in a desiccator.

6.2.5 Before testing, each sample is weighed, determining its mass to the nearest 0,1 g.

6.3 Test equipment

6.3.1 In the following description of the equipment, all dimensions, except those given with tolerances, are nominal.

6.3.2 The test apparatus (Figure A.1) consists of a furnace placed in a thermally insulating environment; cone-shaped air flow stabilizer; a protective screen that provides traction; a sample holder and a device for introducing the sample holder into the oven; the frame on which the furnace is mounted.

6.3.3 The furnace is a pipe made of refractory material (table 2) with a density of (2800±300) kg/m, height (150±1) mm, inner diameter (75±1) mm, wall thickness (10±1) mm. The total wall thickness, taking into account the refractory cement layer fixing the electric heating element, should not exceed 15 mm.

6.3.5 The tube furnace is installed in the center of a shell 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 having recesses on the inside for fixing the ends of the tube furnace. The space between the tube furnace and the shell walls is filled with powdered magnesium oxide with a density of (140±20) kg/m.

6.3.6 The lower part of the tube furnace is connected to a 500 mm cone-shaped air flow stabilizer. The inner diameter of the stabilizer should be (75±1) mm at the top, (10±0.5) mm at the bottom. 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 tightly fitted 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°C].

6.3.7. The upper part of the furnace is equipped with a protective screen made of the same material as the stabilizer cone. Screen height should be 50 mm, inner 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 unit, 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 conical stabilizer to the base of the frame is approximately 250 mm.

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

6.3.10 The installation should be placed so that directional air currents or intense solar radiation, as well as other types of light radiation, do not affect the observation of the flame combustion of the sample in the furnace.

6.3.11 The sample holder (Figure A.3) is made of nichrome or high temperature steel wire. The basis of the holder is a thin mesh made of heat-resistant steel. The mass of the holder shall be (15 ± 2) g. The design of the specimen holder shall allow it to be freely suspended from the bottom of a 6 mm outer diameter stainless steel tube with a 4 mm diameter hole drilled in it.

6.3.12 The device for introducing the sample holder consists of metal rods that move freely within the guides installed on the sides of the casing (Figure A.1). The device for introducing the sample holder must ensure its smooth movement along the axis of the tube furnace and rigid fixation in the geometric center of the furnace.

6.3.13 For temperature measurement use nickel/chromium or nickel/aluminum thermocouples with a nominal diameter of 0.3 mm, insulated junction. Thermocouples must have a 1.5 mm stainless steel protective sheath.

6.3.14 New thermocouples are artificially aged to reduce reflectivity.

6.3.15 The furnace thermocouple should be installed so that its hot junction is at the middle of the height of the tubular furnace at a distance of (10 ± 0.5) mm from its wall. A guide rod is used to set the thermocouple in the indicated position (Figure A.4). The fixed position of the thermocouple is ensured by placing it in a guide tube attached to the protective screen.

6.3.16 The thermocouple for measuring the temperature in the sample should be installed so that its hot junction is at the geometric center of the sample.

6.3.17 The thermocouple for measuring the temperature on the surface of the sample should be installed so that its hot junction from the very beginning of the test was at the middle of the height of the sample in close contact with its surface. The thermocouple should be installed in a position diametrically opposed to the furnace thermocouple (Figure A.5).

6.3.18 Temperature registration is carried out throughout the experiment using appropriate instruments.

The circuit diagram of the installation with measuring instruments is shown in Figure A6.

6.4 Preparing the setup for testing

6.4.1 Remove the sample holder from the oven. The furnace thermocouple shall be installed in accordance with 6.3.15.

6.4.2 Connect the furnace heating element to the power source in accordance with the diagram shown in Figure A.6. During testing, automatic control of the temperature in the furnace should not be carried out.

NOTE A new tube furnace should be warmed up gradually. A stepwise mode with a step of 200°C and holding for 2 hours at each temperature is recommended.

6.4.3 Set a stable temperature regime in the furnace. Stabilization is considered to be achieved provided that the average temperature in the furnace is maintained in the range of 745-755°C for at least 10 minutes. In this case, the permissible deviation from the boundaries of the specified range should be no more than 2 ° C for 10 minutes.

6.4.4 After the furnace has stabilized in accordance with 6.4.3, the temperature of the furnace wall should be measured. Measurements are taken along three equidistant vertical axes. On each axis, the temperature is measured at three points: at the middle of the height of the tube furnace, at a distance of 30 mm up and 30 mm down the axis. For ease of measurement, a scanning device with thermocouples and insulating tubes can be used (Figure A.7). When measuring, close contact of the thermocouple with the furnace wall should be ensured. Thermocouple readings at each point should be recorded only after reaching stable readings for 5 minutes.

6.4.5 The average temperature of the furnace wall, calculated as the arithmetic average of the thermocouple readings at all points listed in 6.4.4, shall be (835 ± 10)°C. The temperature of the furnace wall shall be maintained within the specified limits prior to the start of the test.

6.4.6 In case of incorrect installation of the chimney (upside down), it is necessary to check the compliance of its orientation shown in Figure A.2. To do this, use a thermocouple scanner to measure the temperature of the furnace wall along one axis every 10 mm. The obtained temperature profile with the correct setting corresponds to that depicted by a solid line, with an incorrect one - by a dotted line (Figure A.8).

Note - The operations described in 6.4.2-6.4.4 should be carried out when commissioning a new installation or when replacing the chimney, heating element, thermal insulation, power supply.

6.5 Testing

6.5.1 Remove the sample holder from the oven, check the setting of the oven thermocouple, turn on the power supply.

6.5.2 Stabilize the oven in accordance with 6.4.3.

6.5.3 Place the sample in the holder, install the thermocouples in the center and on the surface of the sample in accordance with 6.3.16-6.3.17.

6.5.4 Insert the sample holder into the oven and install it in accordance with 6.3.12. 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 thermocouple readings in the furnace, at the center and on the surface of the sample.

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

If, after 30 min, temperature balance has not been achieved for at least one of the three thermocouples, the test is continued, checking for temperature balance at intervals of 5 min.

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

6.5.8 Remove the sample holder from the oven, cool the sample in a desiccator and weigh.

Residues (carbonization products, ash, etc.) falling off the sample during or after the test are collected, weighed and included in the mass of the sample after the test.

6.5.9 During the test, record all observations regarding the behavior of the specimen and record the following:

- mass of the sample before testing, g;

- mass of the sample after testing, g;

- initial furnace temperature, °C;

- maximum furnace temperature, °C;

- final temperature of the furnace, °C;

- maximum temperature in the center of the sample, °С;

- final temperature in the center of the sample, °С;

- maximum sample surface temperature, °C;

- final temperature of the sample surface, °C;

- the duration of stable flame combustion of the sample, s.

6.6 Handling results

6.6.1 Calculate for each sample the temperature rise in the oven, in the center and on the surface of the sample:

a) temperature increase in the furnace

b) temperature increase in the center of the sample

c) temperature increase on the sample surface.

6.6.2 Calculate the arithmetic mean (over five samples) of the temperature increase in the furnace, in the center and on the surface of the sample.

6.6.3 Calculate the arithmetic mean value (for five samples) of the duration of stable flame burning.

6.6.4 Calculate the weight loss for each sample (as a percentage of the initial weight of the sample) and determine the arithmetic mean of the five samples.

6.7 Test report

The test report provides the following data:

- date of testing;

- name of the customer;



- name of the material or product;

- code of technical documentation for the material or product;

- description of the material or product, indicating the composition, method of manufacture and other characteristics;

- the name of each material that is an integral part of the product, indicating the thickness of the layer and the method of fastening (for prefabricated elements);

- method of manufacturing a sample;

- test results (indicators determined during testing according to 6.5.9 and design parameters of combustibility according to 6.6.1-6.6.4);

- photographs of samples after testing;

- a conclusion based on the test results indicating which type the material belongs to: combustible or non-combustible;

- duration of the conclusion.

7 Test method for combustible building materials to determine their combustibility groups

Method II

7.1 Scope

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 Test pieces

7.2.1 For each test, 12 specimens, 1000 mm long and 190 mm wide, are made. The thickness of the samples should correspond to the thickness of the material used in real conditions. If the thickness of the material is more than 70 mm, the thickness of the specimens shall be 70 mm.

7.2.2 During the preparation of specimens, the surface to be exposed shall not be treated.

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

As a non-combustible base, asbestos-cement sheets with a thickness of 10 or 12 mm should be used according to GOST 18124.

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

7.2.4 The thickness of paint and varnish coatings must correspond to that adopted in the technical documentation, but have at least four layers.

7.2.5 For materials used both independently (for example, for structures) and as finishing and facing materials, samples must be made in accordance with 7.2.1 (one set) and 7.2.3 (one set).

In this case, tests should be carried out separately for the material and separately using it as finishes and facings, determining the combustibility groups for all cases.

7.2.6 For non-symmetrical laminates with different surfaces, two sets of specimens (according to 7.2.1) are made to expose both surfaces. In this case, the combustibility group of the material is set according to the worst result.

7.3 Test equipment

7.3.1 The test facility consists of a combustion chamber, an air supply system to the combustion chamber, a flue pipe, and a ventilation system for removing combustion products (Figure B.1).

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

- for the inner and outer surface of the walls - sheet steel 1.5 mm thick;

- for the heat-insulating layer - mineral wool boards [density 100 kg/m, thermal conductivity 0.1 W/(m K), thickness 40 mm].

7.3.3 Install the sample holder, ignition source, diaphragm in the combustion chamber. The front wall of the combustion chamber is equipped with a door with glazed openings. An opening with a plug for introducing 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 along the perimeter of the ignition source (Figure B.1), and must ensure the position of the sample relative to the ignition source shown in Figure B.2, the stability of the position of each of the four samples until the end of the test. The sample holder should be mounted on a support frame that allows it to move freely in the horizontal plane. The sample holder and fasteners must not overlap the sides of the exposed surface by more than 5 mm.

7.3.5 The ignition source is a 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 schematic diagram are shown in Figure B.2.

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

7.3.7 The diaphragm is made of a perforated steel sheet 1.5 mm thick with holes with diameters of (20 ± 0.2) mm and (25 ± 0.2) mm and a metal wire mesh located above it at a distance of (10 ± 2) mm with a diameter of not more than 1.2 mm with a mesh size of not more than 1.5x1.5 mm. The distance between the diaphragm and the upper plane of the burner must be at least 250 mm.

7.3.8 A flue pipe with a cross section of (0.25 ± 0.025) m and a length of at least 750 mm is located in the upper part of the combustion chamber. Four thermocouples are installed in the gas outlet pipe to measure the temperature of the exhaust gases (Figure B.1).

7.3.9 The ventilation system for the removal of combustion products consists of an umbrella installed above the flue pipe, an air duct and a ventilation pump.

7.3.10 To measure the temperature during testing, use thermocouples with a diameter of not more than 1.5 mm and appropriate recording instruments.

7.4 Test preparation

7.4.1 Preparation for the test consists in carrying out a calibration in order to establish the gas flow rate (l / min), which ensures the test temperature regime established by this standard in the combustion chamber (table 3).

Table 3 - Test mode

7.4.2 Calibration of the installation is carried out on four samples of steel with dimensions of 1000x190x1.5 mm.

Note - To give rigidity, it is recommended to manufacture calibration samples from sheet steel with flanging.

7.4.3 Temperature control during calibration is carried out according to the readings of thermocouples (10 pcs.) Installed on calibration samples (6 pcs.), And thermocouples (4 pcs.) Installed permanently in the gas outlet pipe (7.3.8).

7.4.4 Thermocouples are mounted along the central axis of any two opposite calibration samples at the levels indicated in Table 3. The hot junction of the thermocouples shall be at a distance of 10 mm from the exposed surface of the sample. Thermocouples must not come into contact with the calibration sample. Ceramic tubes are recommended for isolating thermocouples.

7.4.5 Calibration of the shaft furnace is carried out every 30 tests and when measuring the composition of the gas supplied to the ignition source.

7.4.6 Sequence of operations during calibration:

- install the calibration sample in the holder;

- install thermocouples on calibration samples in accordance with 7.4.4;

- insert the holder with the sample into the combustion chamber, turn on the 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 regime in the combustion chamber does not meet the requirements of Table 3, repeat the calibration at other gas flow rates.

The gas flow rate set during the calibration should be used in the test until the next calibration.

7.5 Testing

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

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

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

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

7.5.5 The duration of exposure to the flame sample from the ignition source shall be 10 min. After 10 minutes, the ignition source is turned off. In the presence of a flame or signs of smoldering, the duration of self-burning (smoldering) is recorded. The test is considered complete after the specimens have cooled down to ambient temperature.

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

7.5.7 For each test, the following indicators are determined:

- flue gas temperature;

- the duration of self-burning and (or) smoldering;

- the length of damage to the sample;

- the mass of the sample before and after the test.

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 the test, the following observations are also recorded:

- time to reach the maximum flue gas temperature;

- transfer of flame to the ends and unheated surface of the samples;

- through burnout of samples;

- formation of a burning melt;

- appearance of the specimens after testing: soot deposition, discoloration, melting, sintering, shrinkage, swelling, warping, cracking, etc.;

- time to flame propagation along the entire length of the sample;

- duration of combustion along the entire length of the sample.

7.6 Processing of test results

7.6.1 After the end of the test, measure the length of the segments of the undamaged part of the samples (according to Figure B3) and determine the residual mass of the samples.

The intact part of the sample is considered to be that which has not burned or charred either on the surface or inside. Soot deposition, discoloration of the sample, local chips, 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 of the results of one test (four samples)

7.6.2.1 The flue gas temperature is assumed to be equal to the arithmetic mean of the simultaneously recorded maximum temperature readings of all four thermocouples installed in the flue pipe.

7.6.2.2 The damage length of one sample is determined by the difference between the nominal length before testing (according to 7.2.1) and the arithmetic mean length of the undamaged part of the sample, determined from the lengths of its segments, measured in accordance with Figure B.3.

Measured lengths of segments should be rounded to the nearest 1 cm.

7.6.2.3 The test specimen damage length is determined as the arithmetic mean of the damage lengths of each of the four test specimens.

7.6.2.4 The mass damage of each specimen is determined by the difference between the mass of the specimen before testing and its residual mass after testing.

7.6.2.5 The mass damage of the specimens is determined by the arithmetic mean of this damage for the four specimens tested.

7.6.3 Processing of the results of three tests (determination of combustibility parameters)

7.6.3.1 When processing the results of three tests, the following combustibility parameters of the building material are calculated:

- flue gas temperature;

- duration of self-burning;

- degree of damage along the length;

- the degree of damage by weight.

7.6.3.2 The temperature of the flue gases (, °C) and the duration of spontaneous combustion (, s) are determined as the arithmetic mean of the results of three tests.

7.6.3.3 The degree of damage along the length (, %) is determined by the percentage of the length of damage to the samples to their nominal length and is calculated as the arithmetic mean of this ratio from the results of each test.

7.6.3.4 The degree of damage by weight (, %) is determined by the percentage of the mass of the damaged part of the samples to the initial one (according to the results of one test) and is calculated as the arithmetic mean of this ratio from the results of each test.

7.6.3.5 The results are rounded off to whole numbers.

7.6.3.6 The material should be assigned to the flammability group in accordance with 5.3 (table 1).

7.7 Test report

7.7.1 The following data is given in the test report:

- date of testing;

- name of the laboratory conducting the test;

- name of the customer;

- name of the material;

Code of technical documentation for the material;

- description of the material indicating the composition, method of manufacture and other characteristics;

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

- a method of manufacturing a sample with an indication of the base material and the method of fastening;

- additional observations during testing;

- characteristics of the exposed surface;

- test results (combustibility parameters according to 7.6.3);

- photograph of the sample after the test;

- conclusion based on the test results on the combustibility group of the material.

For materials tested in accordance with 7.2.3 and 7.2.5, the combustibility groups are indicated for all cases established by these clauses;

- duration of the conclusion.

APPENDIX A (mandatory). SET FOR TESTING BUILDING MATERIALS FOR FIRE-RESISTANCE (method I)

APPENDIX A
(mandatory)

1 - bed; 2 - isolation; 3 - refractory pipe; 4 - magnesium oxide powder; 5 - winding; 6 - damper; 7 - steel rod; 8 - limiter; 9 - sample thermocouples; 10 - stainless steel tube; 11 - sample holder; 12 - furnace thermocouple; 13 - isolation; 14 - insulating material; 15 - pipe made of asbestos cement or similar material; 16 - seal; 17 - air flow stabilizer; 18 - Sheet steel; 19 - draft protection device

Figure A.1 - General view of the installation

1 - refractory pipe; 2 - nichrome tape

Figure A.2 - Furnace winding

Thermocouple in the center of the sample; - thermocouple on the sample surface;

1 - stainless steel tube; 2 - grid (mesh size 0.9 mm, wire diameter 0.4 mm)

Figure A.3 - Sample holder

1 - wooden handle; 2 - welded seam

Furnace thermocouple; - thermocouple in the center of the sample; - thermocouple on the sample surface;

1 - furnace wall; 2 - the middle of the height of the constant temperature zone; 3 - thermocouples in a protective casing; 4 - contact of thermocouples with the material

Figure A.5 — Mutual arrangement of furnace, sample and thermocouples

1 - stabilizer; 2 - ammeter; 3 - thermocouples; 4 - furnace windings; 5 - potentiometer

Figure A.6 - Electrical diagram of the installation

1 - fire-resistant steel rod; 2 - thermocouple in a protective casing made of alumina porcelain; 3 - silver solder; 4 - steel wire; 5 - ceramic tube; 6 - hot layer

Figure A.7 — Thermocouple scanner

Figure A.8 — Furnace wall temperature profiles

APPENDIX B (mandatory). INSTALLATION FOR TESTING BUILDING MATERIALS FOR COMBUSTIBILITY (method II)

APPENDIX B
(mandatory)

1 - combustion chamber; 2 - sample holder; 3 - sample; 4 - gas-burner; 5 - air supply fan; 6 - combustion chamber door; 7 - diaphragm; 8 - ventilation tube; 9 - gas pipeline; 10 - thermocouples; 11 - exhaust umbrella; 12 - viewing window

Figure B.1 - General view of the installation

1 - sample; 2 - gas-burner; 3 - holder base (sample support)

Figure B.2 - Gas burner

1 - undamaged surface; 2 - the boundary of the damaged and undamaged surface; 3 - damaged surface

Figure B.3 - Determining the length of damage to the sample

Electronic text of the document

prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2008

9.1. The test piece, conditioned in accordance with 6.7, is wrapped in a sheet of aluminum foil (nominal thickness 0,2 mm) with a hole 140 mm in diameter cut in the center. In this case, the center of the hole in the foil should coincide with the center of the exposed surface of the sample (Figure A14).

9.2. The test specimen is placed in the holder, placed on the movable platform and the counterweight is adjusted. After that, the holder with the test sample is replaced by the holder with the dummy sample.

9.3. Set the movable burner to its original position according to 7.4.1, adjust the flow rate of gas (19 - 20 ml/min) and air (160 - 180 ml/min) supplied to the movable burner. For the auxiliary burner, the length of the flame is approximately 15 mm.

9.4. The power supply is turned on, and the value of thermoelectric power set during the calibration, corresponding to PPTP 30 kW/m 2 , is set using the regulating thermoelectric converter.

9.5. After reaching the set thermoEMF value, the installation is maintained in this mode for at least 5 minutes. In this case, the value of thermoEMF, recorded by the controlling thermoelectric converter, should differ from that obtained during calibration by no more than 1%.

9.6. Place the shield plate on the protective plate, replace the dummy piece with the test piece, turn on the movable burner mechanism, remove the shield plate, and turn on the time recorder.

The time for these operations should be no more than 15 s.

9.7. After 15 min or when the specimen ignites, the test is terminated. To do this, place the shielding plate on the protective plate, stop the time recorder and the mechanism of the movable burner, remove the holder with the sample and place the simulator sample on the movable platform, remove the shielding plate.

9.8. Set the value of PPTP 20 kW/m2 if ignition was detected in the previous test, or 40 kW/m2 if it was not. Repeat steps 9.5 - 9.7.

9.9. If ignition is detected at PPTP 20 kW/m 2, reduce the PPTP value to 10 kW/m 2 and repeat steps 9.5 - 9.7.

9.10. If there is no ignition at PPTP 40 kW/m2, set the value of PPTP 50 kW/m2 and repeat steps 9.5 - 9.7.

9.11. After determining two values ​​of PPTP, at one of which ignition is observed, and at the other there is no ignition, the value of PPTP is set to 5 kW/m 2 more than the value at which there is no ignition, and operations 9.5 - 9.7 are repeated on three samples.

If ignition is detected at 10 kW/m 2 APRT, then the next test is carried out at 5 kW/m 2 APRT.

9.12. Depending on the results of the tests according to 9.11, the value of PPTP is increased by 5 kW / m 2 (in the absence of ignition) or reduced by 5 kW / m 2 (in the presence of ignition) and the operations of 9.5 - 9.7 are repeated on two samples.

9.13. For each tested sample, the ignition time and the following additional observations are recorded: time and place of ignition; the process of destruction of the sample under the action of thermal radiation and flame; melting, swelling, delamination, cracking, swelling or shrinkage.

9.14. For materials with high compressibility (mineral wool boards), as well as materials that melt or soften during heating, the test should be carried out taking into account 7.2.7.

9.15. For materials that acquire the ability to stick when heated, or form a surface charred layer with low mechanical strength, or contain an air gap under the exposed surface, in order to prevent interference with the movement of the movable burner or damage by the burner to the exposed surface of the sample, tests should be carried out using a stopper in the drive mechanism, eliminating the possibility of contact of the movable burner with the surface of the sample.

9.16. For materials that produce a significant amount of smoke or decomposition products, extinguishing the flame of the mobile burner and precluding the possibility of re-igniting it with the help of an auxiliary burner, the result is recorded in the test report indicating the absence of ignition due to the systematic extinguishing of the flame of the mobile burner by decomposition products.

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

Is drywall combustible or non-combustible?

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

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

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

Drywall combustibility group

Combustible building materials also have their own classification and are divided into four flammability groups: G1, G2, G3 and G4. The table below illustrates the standards that a material must meet in order to obtain one of the four groups.

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

In this case, the following characteristics are measured:

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

Having collected and analyzed all the above indicators obtained in laboratory conditions, the material is assigned to one or another combustibility group. Based on the figures that were recorded when testing a GKL sheet with dimensions of 1000x190x12.5 mm according to the Method ll described above, it was found that the drywall combustibility group is G1. According to this group, the temperature of its flue gases does not exceed 135 ° C, the degree of damage along the length of the sample is not more than 65%, damage by weight is not more than 20%, and the self-burning time is zero.

Video

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

Fire hazard class

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

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

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

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

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 of more than 50 ° C, as well as substances that do not have a melting point (for example, wood, fabrics, etc.).
• dust are dispersed solids and materials with a particle size of less than 850 microns.

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

Substances and materials

According to GOST 12.1.044-89, in terms of flammability, substances and materials are divided into the following groups ( with the exception of building, textile and leather materials):

1. Non-combustible.
2. Slow-burning.
3. combustible.

non-combustible - These are substances and materials that are unable to burn in air. Non-combustible substances can be fire and explosion hazardous (for example, oxidizing agents or substances that release combustible products when interacting with water, atmospheric oxygen, or with each other).

slow-burning - these are substances and materials that can burn in the air when exposed to an ignition source, but are unable to burn on their own after its removal.

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

The essence of the experimental method for determining combustibility is to create temperature conditions conducive to combustion and to evaluate the behavior of the studied substances and materials under these conditions.

Solid (including dust)

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

• the arithmetic mean temperature change in the furnace, on the surface and inside the sample does not exceed 50 °C;
• the arithmetic mean of the weight loss for the five samples does not exceed 50% of their mean of the initial weight 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.

According to the value of the maximum temperature increment (Δt max) and mass loss (Δm), materials are classified:

• slow-burning: Δt max< 60 °С и Δm < 60%;
• combustible: Δt max ≥ 60 °С or Δm ≥ 60%.

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

• flame retardant: τ > 4 min;
• medium flammability: 0.5 ≤ τ ≤ 4 min;
• flammable: τ< 0,5 мин.

gases

In the presence of concentration limits of flame propagation, the gas is classified as fuel ; in the absence of concentration limits for the spread of flame and the presence of a self-ignition temperature, the gas is classified as slow-burning ; in the absence of concentration limits for flame propagation and self-ignition temperature, the gas is classified as non-combustible .

Liquids

In the presence of an ignition temperature, the liquid is classified as fuel ; in the absence of an ignition temperature and the presence of a self-ignition temperature, the liquid is classified as slow-burning . In the absence of flash, ignition, self-ignition temperatures, temperature and concentration limits of flame propagation, the liquid is classified as non-combustible . Combustible 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 . especially dangerous are called flammable liquids with a flash point of not more than 28 ° C.

Classification of building materials

Determination of the combustibility group of a building material

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

1. The ability to spread flame over a surface.
2. smoke generating ability.
3. Toxicity of combustion products.

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

NG (non-flammable)

Non-combustible building materials according to the test results according to methods I and IV () are divided into 2 groups.

Building materials are classified as non-combustible group I

• temperature increase in the furnace is not more than 30 °C;
• the duration of stable flame burning is 0 s;
• calorific value not more than 2.0 MJ/kg.

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

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

It is allowed to refer without testing to non-combustible group I the following building materials without painting their outer surface or with painting the outer surface with compositions without the use of polymeric and (or) organic components:

• concretes, mortars, plasters, adhesives and fillers, clay, ceramic, porcelain stoneware and silicate products (bricks, stones, blocks, slabs, panels, etc.), fiber cement products (sheets, panels, slabs, pipes, etc. .) except in all cases for materials made using polymeric and (or) organic binder aggregates and fibers;
• inorganic glass products;
• products from alloys of steel, copper and aluminum.

Building materials that do not meet at least one of the above indicated values ​​​​of the parameters I and II of the group of incombustibility belong to the group of combustible 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 and not standardized.

Combustible building materials, depending on the values ​​of the combustibility parameters determined by method II, are divided into four combustibility groups (G1, G2, G3, G4) according to the table. Materials should be assigned to a certain combustibility group, provided that all the arithmetic mean values ​​of the parameters established by the table for this group correspond.

G1 (low combustible)

Slightly combustible - these are materials with a flue gas temperature of not more than 135 ° C, the degree of damage along the length of the test sample is not more than 65%, the degree of damage by weight of the test sample is not more than 20%, the duration of self-burning is 0 seconds.

G2 (moderately flammable)

Moderately combustible - these are materials with a flue gas temperature of not more than 235 ° C, the degree of damage along the length of the test sample is not more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of self-burning is not more than 30 seconds.

G3 (normally combustible)

Normal flammable - these are materials with a flue gas temperature of not more than 450 ° C, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is not more than 50%, the duration of self-burning is not more than 300 seconds.

G4 (highly flammable)

highly flammable - these are materials with a flue gas temperature of more than 450 ° C, the degree of damage along the length of the test sample is more than 85%, the degree of damage by weight of the test sample is more than 50%, the duration of self-burning is more than 300 seconds.

table

Video, what is a flammability group

Sources: ; Baratov A.N. Combustion - Fire - Explosion - Safety. -M.: 2003; GOST 12.1.044-89 (ISO 4589-84) Occupational safety standards system. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination; GOST R 57270-2016 Building materials. Test methods for combustibility.