Flammability test method

This standard specifies a method for testing building materials for flammability and their classification according to flammability groups.

This standard applies to all homogeneous and layered combustible building materials.

This standard uses references to the following regulatory documents:
GOST 12.1.005-88 SSBT . General sanitary and hygienic requirements for the air in the working area;
GOST 12.1.019-79 SSBT . Electrical safety. General requirements and nomenclature of types of protection;
GOST 18124-95  Asbestos-cement flat sheets;
GOST 30244-94 Building  materials. Flammability test methods;
ST SEV 383-87  Fire safety in construction. Terms and Definitions.

In this standard, the terms and definitions of ST SEV 383 are used, as well as the following terms with the corresponding definitions:

3.1. Flammability - the ability of substances and materials to ignite.  

3.2. Ignition is the initiation of flame combustion under the action of an ignition source and is characterized by sustained flame combustion in this standard test.  

3.3. Ignition time is the time from the start of the test to the onset of a stable flame combustion.  

3.4. Stable flame combustion is combustion that continues until the next exposure of the sample to the flame from the ignition source.  

3.5. Surface heat flux density (PPHF) is a radiant heat flux affecting a unit of sample surface.  

3.6. Critical surface heat flux density (KPPTP) is the minimum value of the surface heat flux density at which a stable flame combustion occurs.  

3.7. Exposed surface is the surface of a specimen exposed to radiant heat flux and flame from an ignition source during a flammability test.  

4.1. The essence of the method consists in determining the flammability parameters of the material at the levels of exposure of the sample surface to a radiant heat flux and flame from an ignition source specified by the standard.

The parameters of the material's flammability are KPPTP and the ignition time.

To classify materials by flammability groups, KPPTP is used.

4.2. The density of the radiant heat flux should be in the range from 10 to 50 kW / m ²

4.3. The initial density of the radiant heat flux during testing (PPTP) is equal to 30 kW / m ²

5.1. Combustible building materials (according to GOST 30244), depending on the size of the KPPTP, are divided into three groups of flammability: B1, B2, B3 (table 1).

Table 1

6.1. For testing, 15 samples are made, having the shape of a square, with a side of 165 mm and a deviation of minus 5 mm. The thickness of the samples should be no more than 70 mm. At each value of the PPTP, tests are carried out on three samples.

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

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

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

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

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

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

6.4. Paint and varnish coatings, as well as roofing mastics should be applied to the base in at least four layers, while the material consumption when applied to the base of each layer must correspond to that adopted in the technical documentation.

6.5. For materials used both independently (for example, for structures) and as finishing and facing, samples should be made in accordance with 6.1 (one set) and 6.3 (one set).

In this case, the tests are carried out separately for the material and separately using it as finishes and linings.

6.6. For laminates with different surface layers, make two sets of specimens (according to 6.1) in order to expose both surfaces. In this case, the flammability group of the material is set according to the worst result.

6.7. Before testing, the samples are conditioned to achieve constant weight at a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 5%. Mass constancy is considered achieved if, after two successive weighings with an interval of 24 hours, the difference in the mass of the samples is no more than 0.1% of the initial mass of the sample.

7.1.1. A general view of the flammability test setup is shown in Figure A1.

The installation consists of the following main parts:

• support bed;
• movable platform;
• source of radiant heat flux (radiation panel);
• ignition system (auxiliary stationary burner, movable burner with mechanized and manual movement system).

7.1.2. The auxiliary equipment includes: a sample holder, a shielding plate, a holder with a simulator sample, a gas-air mixture flow control system, regulating and recording devices, a heat flow meter, and a time recorder.

7.1.3. The unit must be equipped with a protective screen and an exhaust hood.

7.1.4. All dimensions shown in the following installation descriptions as well as in the figures are nominal, except those indicated with tolerances.

7.2.1. The design of the support frame, the main units and details of the moving platform movement system are shown in Figures A2 and A3.

7.2.2. The base of the support frame is made in the form of a rectangular frame measuring 275x230 mm from a square section 25x25 mm with a wall thickness of 1.5 mm.

At the corners of the frame, four vertical supports with a diameter of 16 mm are mounted to attach the protective plate. The distance from the frame to the cover plate is 260 mm.

7.2.3. The cover plate has the shape of a square with a side of 220 mm, the thickness of the plate is 4 mm. A hole with a diameter of 150 mm is cut in the center of the cover plate. Along the edge of the hole on the upper side of the slab, a 4 mm bevel is cut off at an angle of 45 °.

7.2.4. The movable sample platform has the shape of a square with a side of 180 mm, the platform thickness is 4 mm. A vertical rod with a boss at the lower end of the rod is installed in the center of the lower side of the platform. Rod diameter - 12 mm, length 148 mm.

7.2.5. The moving platform movement system consists of two vertical guides (rods at least 355 mm long and 20 mm in diameter), a horizontal movable bar (section 25 × 25 mm) with two bushings at the ends of the bar and a hole in the center for the vertical rod of the movable platform, as well as lever with a counterweight.

7.2.6. The vertical rails are mounted in the center of the short sides of the frame (base of the support frame).

The horizontal movable bar is installed on vertical guides. The bushings must ensure free movement of the bar along the guides. The position of the bar is fixed manually using screws.

A lever with a counterweight is installed under the horizontal bar. The lever should end with a roller resting against the bore of the vertical rod of the movable platform.

7.2.7. The counterbalanced lever should ensure the movement of the platform with the sample to the protective plate until a tight contact of the surface of the specimen and the protective plate is achieved. The specified requirements are met by a lever with a length of approximately 320 mm with a counterweight of approximately 3 kg.

When melting, softening or shrinking the sample, the platform may be displaced relative to the protective plate by a distance of no more than 5 mm. To meet this requirement, an adjustable stopper is installed or non-combustible spacers are used between the platform and the protective plate.

7.3.1. The radiation panel (Figures A4, A5) must ensure the levels of exposure to radiant heat flux specified by the standard in the center of the opening of the protective plate, in the plane coinciding with its lower surface.

7.3.2. The radiation panel is installed on the vertical guides of the support frame. In this case, the distance from the lower edge of the radiation panel to the upper plane of the protective plate should be 22 ± 1 mm.

7.3.3. The radiation panel consists of a casing with a heat-insulating layer and a heating element. A non-combustible mineral fiber material is used as a heat-insulating layer.

7.3.4. A heating element with a diameter of 8 to 10 mm and a length of approximately 3.5 m (rated power 3 kW) is rolled up in a frusto-conical shape and attached to the inner surface of the casing.

7.3.5. Two thermoelectric converters are installed on the surface of the heating element at two diametrically opposite points. Each of them is attached to the coil of the heating element at a distance of 1/3 to 1/2 of the height of the casing of the radiation panel from its upper edge.

The fastening method should ensure tight contact of thermoelectric converters with the surface of the heating element. One of the recommended fastening methods is shown in Figure A5.

One of the thermoelectric converters is used to control the temperature of the heater (regulating thermoelectric converter), the second is used to control the temperature of the heater (controlling the thermoelectric converter).

7.4.1. The movable burner must move from its original position above the radiant panel to an operating position inside the panel. The design of a movable burner and its movement system are shown in Figures A6 - A8.

7.4.2. The auxiliary burner is designed to ignite the movable burner in the event of its extinction. The pilot burner nozzle diameter is 1 to 2 mm.

7.4.3. In the working position, the flame of the movable burner must be located above the center of the hole in the protective plate in a plane perpendicular to the direction of movement of the burner. In this case, the center of the burner nozzle should be located at a distance of 10 ± 1 mm from the plane of the movable plate.

7.4.4. The movable burner should move from the home position to the working position every 4 + 0.4 s. The dwell time of the burner in the working position should be 1 s.

7.5.1. The sample holder is a flat metal sheet, on the upper surface of which there are sides for mounting and fixing the sample (Figure A9). On the bottom surface of the holder there are guides and a stopper that fixes the position of the holder.

7.5.2. The shielding plate (Figure A10) is intended to protect the sample surface from heat flux. The shielding plate is made of 2 mm thick sheet aluminum or stainless steel.

7.5.3. A simulator is made of a non-combustible mineral fiber material with a density of 200 ± 50 kg / m ³  (Figure A11). The holder of the simulator sample is made of a non-combustible material with a density of 825 ± 125 kg / m ³ .

7.5.4. The system for regulating the flow rate of the gas-air mixture (Figure A12) is connected to the sources of gaseous fuel (propane or propane-butane mixture) and air, contains needle valves, flow meters with an upper measurement limit of at least 1.2 l / h (for gas) and at least 12 l / h (for air) with an error of no more than 4%. It is also recommended to place filters on the fuel and air supply lines to protect the flow meters from impurities.

7.5.5. The device regulating the temperature of the heating element of the radiation panel must be designed for a power of at least 3 kW and a current of at least 15 A. To record the temperature, it is recommended to use a device with an accuracy class of at least 0.5.

7.5.6. To measure PPTP, it is recommended to use a device with a measurement range from 1 to 75 kW / m ² , the measurement error is no more than 5%. To register the readings of the heat flow meter, a recording device with an accuracy class of at least 0.1 is used.

7.5.7. It is recommended to use devices with a measurement range of up to 1 h as a time recorder; the measurement error should be no more than 1 s.

7.5.8. The installation site is equipped with protective screens and exhaust ventilation (Figure A13). An air flow reflector is installed in the exhaust hood, providing an air speed of 2 to 3 m / s in the gaps with an air flow rate of 0.25 to 0.35 m ³ / s.

8.1.1. The purpose of the calibration is to establish the values ​​of PPTP required by this standard according to 4.2, as well as the uniformity of its distribution within the exposed surface of the sample.

8.1.2. The uniformity of the heat flux distribution over the exposed surface of the sample is ensured if the following conditions are met:

• the deviation of PPTP at any four diametrically opposite points of a circle with a diameter of 50 mm from the value of PPTP in the center of the exposed surface should be no more than ± 3%;
• the deviation of PPTP at any four diametrically opposite points of a circle with a diameter of 100 mm from the value of PPTP in the center of the exposed surface should be no more than ± 5%.

8.1.3. Establishment of the values ​​of PPTP required by the standard is carried out by determining the dependence of PPTP in the center of the exposed surface on the temperature of the heating element.

8.1.4. Calibration is carried out on samples (3 pcs.), Having the shape of a square, with a side of 165 mm and a deviation of minus 5 mm. The thickness of the calibration block must be at least 20 mm. For the manufacture of a calibration sample, asbestos-cement sheets are used in accordance with GOST 18124.

A hole is cut out in the calibration samples for installing the heat flux meter: in the first sample - in the center, in the second sample - at any point of a circle with a diameter of 50 mm, in the third sample - at any point of a circle with a diameter of 100 mm.

8.1.5. Calibration is carried out during metrological certification of the installation or replacement of the heating element and / or thermoelectric converters.

8.2.1. During calibration, the movable burner must be in its original position, the valves of the fuel and air supply systems are closed.

8.2.2. Install the heat flux meter into the calibration sample with a hole in the center of the exposed surface.

8.2.3. Place the calibration piece in the holder and place it on the movable platform.

8.2.4. The power supply is switched on and by changing the power supplied to the heating element of the radiation panel, the thermoEMF value is selected according to the regulating thermoelectric converter, at which a heat flux with a density of 50 kW / m ^{2 is} provided in the center of the exposed surface .

8.2.5. Maintain the installation in the heating mode according to 8.2.4 for at least 10 min and record the thermoEMF value of the controlling thermoelectric converter.

8.2.6. Repeat the operations according to 8.2.4, 8.2.5 in order to determine the thermoEMF values ​​that provide heat fluxes with a density of 45, 40, 35, 30, 25, 20, 10, 5 kW / m ² in the center of the exposed surface .

8.2.7. After performing the operations according to 8.2.6, install the heat flux meter in the calibration sample with a hole on a circle with a diameter of 50 mm and repeat the operations according to 8.2.3 - 8.2.5 for heat fluxes with a density of 50, 40, 30, 20, 10 kW / m ² .

These measurements are repeated for each of four diametrically opposite points of the circle, changing the position of the sample in the holder.

8.2.8. Repeat the calibration procedure of 8.2.7 on a calibration piece with a hole in a circle with a diameter of 100 mm.

8.2.9. If the PPTP measurement results do not comply with the requirements of 8.1.2, the heating element of the radiation panel should be replaced.

8.2.10. The calibration control of the installation is carried out every 60 hours of operation of the radiation panel according to the value of PPTP equal to 30 kW / m ² in the center of the exposed surface.

The calibration of the installation is repeated if the deviation of the measured value of the PPTP is more than 0.06 kW / m ² .

9.1. The test piece, conditioned in accordance with 6.7, is wrapped in a sheet of aluminum foil (nominal thickness 0.2 mm), in the center of which a hole with a diameter of 140 mm is cut. In this case, the center of the hole in the foil must coincide with the center of the exposed surface of the sample (Figure A14).

9.2. Place the test piece in the holder, place it on the movable platform and adjust the counterweight. After that, the holder with the test specimen is replaced with the holder with the simulated specimen.

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

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

9.5. After reaching the specified value of thermoEMF, the installation is kept 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 shielding plate on the shielding plate, replace the simulator with a test specimen, turn on the movable burner mechanism, remove the shielding plate, and turn on the time recorder.

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

9.7. Stop the test after 15 minutes or if the specimen ignites. To do this, place the shielding plate on the protective plate, stop the time recorder and the movable burner mechanism, remove the holder with the sample and place the simulator sample on the movable platform, remove the shielding plate.

9.8. The value of PPTP is set to 20 kW / m2, if ignition was recorded in the previous test, or 40 kW / m2 in its absence. Repeat operations 9.5 - 9.7.

9.9. If at PPTP 20 kW / m ²  ignition is recorded, reduce the value of PPTP to 10 kW / m ²  and repeat the operations in 9.5 - 9.7.

9.10. If there is no ignition at PPTP 40 kW / m ²  , set the value of PPTP 50 kW / m2 and repeat the operations in 9.5 - 9.7.

9.11. After determination of two quantities PPTP, at one of which there is inflammation, while the other - is absent set value PPTP 5 kW / m ²  greater than the value at which no ignition, and repeat the operations of 9.5 - 9.7 on the three samples.

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

9.12. Depending on the test results according to 9.11, the value of PPTP is increased by 5 kW / m ²  (in the absence of ignition) or decreased 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 test piece tested, the ignition time and the following additional observations are recorded: time and place of ignition; the process of destruction of the sample under the influence 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 adhere when heated, or form a surface carbonized 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 torch with the sample surface.

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

The test report contains the following data:

• the name of the testing laboratory;
• customer name;
• manufacturer (supplier) name;
• description of the material or product, technical documentation, as well as the trade mark, composition, thickness, density, mass and method of making samples, characteristics of the exposed surface, for laminated materials - the thickness of each layer and the characteristics of the material of each layer;
• flammability parameters: PPTP, ignition time at PPTP for each of the samples;
• conclusion about the flammability group of the material, indicating the value of the KPPTP;
• additional observations when testing the sample: time and place of ignition; the process of destruction of the sample under the influence of thermal radiation and flame; melting, swelling, delamination, cracking, swelling or shrinkage.

The room in which the tests are carried out must be equipped with supply and exhaust ventilation. The operator's workplace must meet the electrical safety requirements in accordance with GOST 12.1.019 and sanitary and hygienic requirements in accordance with GOST 12.1.005.