Group r3 r4. Fire safety requirements for building materials

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 according to 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 layered 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 of the following dimensions are made: 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 give 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 heating cabinet 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 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 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 oven. 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, °С;

- 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, prepare two sets of specimens (according to 7.2.1) in order 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 gas outlet 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)° WITH.

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 removing 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.) Permanently installed 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 samples 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 damage length of specimens during testing is determined as the arithmetic mean of the damage lengths of each of the four specimens tested.

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 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

The most important quality of the material used in construction is its combustibility. Combustibility is the property of a material to resist the effects of a flame. Therefore, five flammability groups are legally defined. Four groups of combustible materials and one non-combustible. In Federal Law No. 123, they are defined by abbreviations: G1, G2, G3, G4 and NG. Where NG stands for non-combustible.

The main indicator in determining the combustibility group of a particular material is the burning time. The longer the material can withstand, the lower the combustibility group. Burn time is not the only indicator. Also, fire testing will evaluate the interaction of the material with the flame, whether it will support combustion and to what extent.

The combustibility group is inextricably linked with other fire resistance parameters of the material, such as flammability, release of toxic substances, and others. Together, the fire resistance indicators make it possible to judge the flammability class. That is, the flammability group is one of the indicators for assigning a flammability class, it precedes it. Let's take a closer look at the elements of assessing the fire resistance of a material.

All substances in nature are divided into. Let's list them:

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

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

The fire-fighting characteristics of building materials also include:

• combustibility;
• flammability;
• the ability to release toxins when heated and burned;
• intensity of smoke formation at high temperatures.

Flammability groups

The tendency of building materials to burn is indicated by the symbols G1, G2, G3 and G4. This series begins with the combustibility group of slightly combustible substances, designated by the symbol G1. The series ends with a group of highly flammable G4s. Between them is a group of materials G2 and G3, which are moderately combustible and normally combustible. These materials, including the group of low combustible G1, are mainly used in building technologies.

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

For completely non-combustible building materials, fire safety characteristics are not investigated and standards are not established for them.

Of course, the G4 material group also finds its application, but due to its high tendency to burn, it requires additional fire protection measures. As an example of such additional measures, a floor-by-floor fire cut-off made of steel inside the ventilation facade structure can be used if a windproof membrane with a combustibility group G4, that is, combustible, was used. In this case, the cutoff is designed to stop the flame inside the vent gap within one floor.

Application in construction

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

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

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

For example, for the construction of buildings for kindergartens, schools, hospitals or nursing homes, only materials and NG combustibility groups are allowed.

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

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

• structures made of non-combustible materials - K0;
• constructions from materials of group G4 - K3.

Any building structures should not spread latent combustion. In the partitions of the walls, the places of their connection there should not be voids that are separated from one another by continuous fillings of combustible materials.

Confirmation of the class and degree of flammability

Flammability test of facade finishing materials. Video

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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 building products, including in the context of fire safety. Those materials that until recently were considered dangerous have ceased to be such, but this does not mean that this characteristic can be ignored when building a house. In the end, no one is safe from accidents, and minimizing possible damage from fire is the direct responsibility of the homeowner.

Terminology

Speaking about construction in terms of exposure to fire and high temperatures, two concepts need to be distinguished - fire resistance and fire safety.

fire resistance as the term refers not to materials, but to building structures and characterizes their ability to resist the effects of fire without loss of strength and bearing capacity. This parameter is spoken about 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 120 mm porous ceramic block partitions 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 the ability to spread the flame over the surface and smoke formation, toxicity of combustion products. Within the framework of each quality, materials are tested in laboratory conditions, they are assigned a certain class, which will be noted in the product labeling.

• By combustibility emit non-combustible (NG) and combustible (G1, G2, G3, and G4) materials, where G1 is slightly combustible, and G4 is highly combustible. Products of the NG class are not classified, so the remaining classes are applicable only to combustible products.
• Flammability- from B1 (slightly flammable) to B3 (highly flammable).
• By toxicity- from T1 (low risk) to T4 (extremely dangerous).
• Smoke generating capacity- from D1 (weak smoke formation) to D3 (strong smoke formation).
• By the ability to spread the flame over the surface- from RP-1 (not spreading flame) to RP-4 (strongly spreading).

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

Concrete and cellular concrete

ordinary concrete belongs to the class of non-combustible materials. For 2-5 hours, it perfectly tolerates temperatures up to 250-300 ° C, but at temperatures above 300 ° C, irreversible changes occur in the material. Loss of strength and cracking metal reinforcement located inside the blocks contributes, therefore reinforced concrete structures resist fire much worse than concrete ones. Another factor leading to loss of strength is Portland cement, which is part of some concretes. On the other hand, lean concrete with a low cement content and a high content of fillers, which is often used for laying floors on the ground, resists fire better. Lightweight concrete with a bulk density of less than 1800 kg/m³ is also more resistant. And yet, despite some shortcomings, there are qualities that make concrete an attractive material in terms of fire safety. Its heating rate is low, it has low thermal conductivity, and a significant part of the heat during its heating will be spent on the evaporation of 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. Different manufacturers may have different specifications for this material. 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 (over 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 the bearing capacity of structures by inviting a specialist builder. In some cases, even after a fire with the collapse of a wooden truss structure, cellular concrete walls can be restored.

Ceramic bricks and porous blocks

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

High temperatures make ceramic wall materials more brittle 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 attachment point. 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 that, after restoration, a burning smell will remain in a house made of ceramic bricks or blocks is 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 of it without special protective measures have a flammability group G4, flammability B3, flame propagation RP3 and RP4, smoke generation D2 and D3 and toxicity 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 flame retardants.

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

When applying special compositions on the surface, brushes, rollers or a spray gun are used, however, 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 autoclaving with flame retardants under pressure, which can only be carried out in production.

Using these methods, it is possible to reduce the combustibility 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 construction made of wood OSB and expanded polystyrene. But from the point of view of construction, they can still be considered wall building material. Both OSB and polystyrene foam, which are part of the panels, are themselves combustible, but given that a fire usually occurs in the premises of a house, the danger of SIP is greatly exaggerated, since the inside of the product is sheathed with non-combustible drywall sheets. Outside, they are often finished with siding having a flammability class G1 or G2, or non-combustible plaster. Yes, and the expanded polystyrene itself is treated with flame retardants, so the entire wall structure has good fire safety performance.

Flammability group materials is determined according to GOST 30244-94 "Building materials. Test methods for combustibility", which corresponds to the International Standard ISO 1182-80 "Fire tests - Building materials - Non-combastibility test". Materials, depending on the values ​​of the combustibility parameters determined according to this GOST, are divided into non-combustible (NG) and combustible (G).

Materials refer to non-combustible with the following values ​​of combustibility parameters:

1. temperature increase in the furnace is not more than 50°С;
2. weight loss of the sample is not more than 50%;
3. the duration of stable flame burning is not more than 10 sec.

Materials that do not satisfy at least one of the indicated parameter values ​​are classified as combustible.

Combustible materials, depending on the values ​​of the combustibility parameters, are divided into four combustibility groups in accordance with table 1.

Table 1. Combustibility groups of materials.

Flammability group of materials is determined according to GOST 30402-96 "Construction materials. Flammability test method", which complies with the international standard ISO 5657-86.

In this test, the sample surface is subjected to radiant heat flux and flame from an ignition source. In this case, the surface heat flux density (SPTP) is measured, that is, the magnitude of the radiant heat flux acting on the unit surface area of ​​the sample. Ultimately, the Critical Surface Heat Flux Density (CCTP) is determined - the minimum value of the surface heat flux density (CCTP) at which stable flaming combustion of the sample occurs after exposure to a flame.

Materials are divided into three flammability groups, depending on the values ​​of the CATI, shown in Table 2.

Table 2. Flammability groups of materials.

To classify materials according to their smoke emission abilities use the value of the smoke generation coefficient, which is determined according to GOST 12.1.044.

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

Depending on the value of the relative smoke density, materials are divided into three groups:
D1- with low smoke generating capacity - smoke generation coefficient up to 50 m²/kg inclusive;
D 2- with moderate smoke generating capacity - smoke generation coefficient from 50 to 500 m²/kg inclusive;
D3- with high smoke generating capacity - smoke generating coefficient over 500 m²/kg.

Toxicity group combustion products of building materials is determined according to GOST 12.1.044. The combustion products of the material sample are sent to a special chamber where experimental animals (mice) are located. Depending on the state of the experimental animals after exposure to combustion products (including a lethal case), the materials are divided into four groups:
T1- little dangerous;
T2- moderately dangerous;
T3- highly dangerous;
T4- extremely dangerous.

The Technical Code of Practice establishes a fire-technical classification of building materials, products, structures, buildings and their elements. This normative act regulates the classification of materials, products and structures for fire hazard, depending on the fire performance, as well as methods of determination.

The fire hazard of building materials is determined by the following fire-technical characteristics or their combination:

combustibility;

Flammability;

Spread of flame over the surface;

Toxicity of combustion products;

smoke generating ability.

Building materials, depending on the values ​​​​of combustibility parameters, determined in accordance with GOST 30244, are divided into non-combustible
and combustible. For building materials containing only inorganic (non-combustible) components, the “combustibility” characteristic
not defined.

Combustible building materials are classified according to:

1. Values ​​of combustibility parameters determined according to GOST 30244 into combustibility groups:

G1, low combustible;

G2, moderately combustible;

G3, normally combustible;

G4, highly flammable.

2. The values ​​​​of the critical surface heat flux density according to GOST 30402 for flammability groups:

B1, flame retardant;

B2, moderately flammable;

B3, highly flammable.

3. In values ​​of the critical surface heat flux density according to GOST 30444 for groups according to flame propagation:

RP1, not distributing;

RP2, weakly propagating;

RP3, moderately spreading;

RP4, strongly spreading.

4. The lethal effect of gaseous combustion products on the mass of material per unit volume of the exposure chamber
according to GOST 12.1.044 into groups according to the toxicity of combustion products:

T1, low risk;

T2, moderately dangerous;

T3, highly dangerous;

T4, extremely dangerous.

4. Values ​​of the smoke generation coefficient according to GOST 12.1.044 into groups according to smoke generation ability:

D1, with low smoke generating capacity;

D2, with moderate smoke-forming ability;

D3, with high smoke generating ability.