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- a genre of fine art, the main task of which is to display the surrounding nature both in its original form and in its changed form... home Law and law Smoke-forming ability is the ability of substances and materials to emit smoke during combustion or thermal decomposition. According to Part 9 of Article 13 Federal Law No. 123-FZ of July 22, 2008 “
- Technical regulations
- about the requirements
- fire safety
» according to their smoke-generating ability, combustible building materials, depending on the value of the smoke generation coefficient, are divided into the following groups: With low smoke generation capacity (D1), having a smoke generation coefficient of less than 50 square meters per kilogram With moderate smoke-forming ability (D2), having a smoke-formation coefficient of at least 50, but not more than 500 square meters per kilogram
With a high smoke-forming capacity (S), having a smoke generation coefficient of more than 500 square meters per kilogram luminous flux recorded using a photometric system.
To conduct tests at the Federal State Budgetary Institution SEU FPS IPL in the Republic of Mordovia, it is necessary to provide 10–15 samples of the test material with dimensions of 40×40 mm and actual thickness, but not more than 10 mm (for foam plastic samples, thickness up to 15 mm is allowed). Paint and varnish and film coatings are tested applied to the same base as used in the actual design. If the area of application of varnishes and paints is unknown, then they are tested applied to aluminum foil 0.2 mm thick.
Before testing, prepared samples are kept at a temperature of (20±2) °C for at least 48 hours, then weighed with an error of no more than 0.01 g. The samples must characterize the average properties of the material being tested.
Testing of samples is carried out in a thermophysical laboratory at the “Smoke” testing facility.
Scheme of the “Smoke” installation for determining the smoke formation coefficient of solids and materials
1 - combustion chamber; 2 - sample holder; 3 - quartz glass window; 4, 7 - purge valves; 5- light receiver; 6 - measurement chamber; 8 - quartz glass; 9 - light source; 10 - safety membrane; 11 - fan; 12 - guide visor; 13 - pilot burner; 14 - liner; 15 - electric heating panel.
Installation appearance
Testing of samples is carried out in two modes: in smoldering mode and in combustion mode using a gas burner. Five samples are tested in each mode.
The results are processed according to the GOST 12.1.044-89 methodology.
The smoke generation coefficient Dm in m 2 kg -1 is calculated by the formula:
where V is the capacity of the measurement chamber, m3; L – path length of a light beam in a smoky environment, m; m – sample mass, kg; T0, Tmin – respectively, the values of the initial and final light transmission, %.
For each test mode, the smoke generation coefficient is determined as the arithmetic average of the results of five tests.
The smoke generation coefficient of the material under study is taken to be the larger value of the smoke generation coefficient calculated for the two test modes.
After testing and payment of the test cost, fire testing laboratory employees prepare reporting documentation.
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Carrying out the test
Place the sample in the holder, fix its position using fastening devices, place the holder with the sample on the platform and insert it into the chamber.
Close the camera door and start the stopwatch. After holding for 2 minutes, the burner flame is brought into contact with the sample at point “0” located along the central axis of the sample. Leave the flame in this position for (10±0.2) minutes. After this time, return the burner to its original position.
If the sample does not ignite within 10 minutes, the test is considered complete.
If the sample ignites, the test is completed when the flame combustion stops or after 30 minutes from the start of exposure of the sample to the gas burner by forced extinguishing.
During the test, the ignition time and duration of flame combustion are recorded.
Measure the length of the damaged part of the sample along its longitudinal axis for each of the five samples. Measurements are carried out with an accuracy of 1 mm.
Damage is considered to be burnout and charring of the sample material as a result of the spread of flame combustion over its surface. Melting, warping, sintering, swelling, shrinkage, changes in color, shape, violation of the integrity of the sample (ruptures, surface chips, etc.) are not damage.
The flame propagation length is determined as the arithmetic mean along the length of the damaged part of five samples.
The value of the KPPTP is established based on the results of measuring the flame propagation length
Smoke coefficient
Smoke generation coefficient is an indicator characterizing the optical density of smoke generated during flaming combustion or thermal-oxidative destruction (smoldering) of a certain amount of solid substance (material) under special test conditions.
The smoke production coefficient value should be used to classify materials according to their smoke generation ability. There are three groups of materials:
with low smoke-generating ability - smoke generation coefficient
up to 50 m 2 kg -1 inclusive;
with moderate smoke-forming ability - smoke production coefficient
St. 50 to 500 m 2 kg -1 inclusive;
with high smoke-generating ability - smoke generation coefficient
St. 500 m 2 kg -1.
The smoke emission coefficient value must be included in the standards or technical specifications on solids and materials.
The essence of the method for determining the smoke generation coefficient is to determine the optical density of the smoke formed during the combustion or smoldering of a known amount of the test substance or material distributed in a given volume.
Installation for determining the smoke generation coefficient
1 - the combustion chamber; 2 - sample holder; 3 - quartz glass window; 4, 7 - purge valves; 5 - light receiver; 6 - measurement chamber; 8 - quartz glass; 9 - Light source; 10 - safety membrane; 11 - fan: 12 - guide visor; 13 - pilot burner: 14- liner; 15 -electric heating panel.
For testing, prepare 10 - 15 samples of the test material with dimensions (40x40) mm and actual thickness, but not more than 10 mm (for foam samples, thickness up to 15 mm is allowed). Paint and varnish and film coatings are tested applied to the same base as used in the actual design. If the area of application of varnishes and paints is unknown, then they are tested applied to aluminum foil 0.2 mm thick.
Before testing, the prepared samples are kept at a temperature of (20±2) °C for at least 48 hours, then weighed with an error of no more than 0.01 g. The samples must characterize the average properties of the material being tested.
Testing of samples is carried out in two modes: in smoldering mode and in combustion mode using a gas burner (burner flame length 10 - 15 mm).
The prepared sample is placed in a stainless steel boat. Open the door of the combustion chamber and without delay install the boat with the sample in the holder, after which the door is closed.
The test is stopped when the minimum light transmittance value is reached.
In case minimum value light transmission is outside the working range or is close to its boundaries, it is possible to reduce the path length of the light beam (the distance between the source and the light receiver) or change the dimensions of the sample.
When tested in smoldering mode, samples should not spontaneously ignite. In the case of spontaneous ignition of the sample, subsequent tests are carried out at a heat flux density value reduced by 5 kW m -2. The heat flux density is reduced until the spontaneous ignition of the sample stops during testing.
Five samples are tested in each mode.
The smoke generation coefficient (D m) in m 2 kg -1 is calculated using the formula
Where V- capacity of the measurement chamber, m 3 ;
L- path length of a light beam in a smoky environment, m;
m- sample mass, kg;
T 0,Tmin- respectively, the values of the initial and final light transmission, %.
Smoke coefficient- this is an indicator characterizing the optical density of smoke formed during the flame or thermal-oxidative destruction () of a certain amount of solid substance (material) under special test conditions. The smoke generation coefficient is determined by.
Solid substances (materials) are classified according to their smoke-forming ability according to the data given in the table.
Classification
The smoke generation coefficient is used in fire safety standards for the use of building materials in buildings (structures), to confirm compliance with the requirements specified in the regulatory and technical documentation. The value of the smoke generation coefficient is included in the standards or technical specifications for solid substances (materials).
More details about the classification of combustible building materials according to the smoke-generating ability of the material:
Values
| Substances and materials | Smoke generation coefficient, m 2 /kg -1 | |
| Smoldering | Combustion | |
| Corrugated cardboard | – | 1 |
| Flax loosened | – | 3,37 |
| Wood | 345 | 23 |
| Decorative satin | 32 | 32 |
| Cotton | – | 35 |
| Cardboard grade "G" | – | 35 |
| Reps | 50 | 50 |
| Lumber hardwood with three layers of varnish PF-283 | – | 53 |
| Fiber board from the osprey of the Zhichevskaya paper mill | – | 54 |
| Tent canvas | 57 | 58 |
| Softwood lumber with two layers of glyphthalic drying oil | – | 61 |
| Viscose fabric | 63 | 63 |
| Glued plywood + sliced veneer | – | 69 |
| Butyl alcohol | – | 80 |
| Chipboard (chipboard) | 760 | 90 |
| Fiberglass | – | 92 |
| Wood fiber (birch, aspen) | 323 | 104 |
| Wool-blend furniture fabric | 103 | 116 |
| Tobacco "Yubileiny" | 240 | 120 |
| Fiberboard (fibreboard) | 879 | 130 |
| Plywood | 700 | 140 |
| Pine | 759 | 145 |
| Birch | 756 | 160 |
| Turbine oil | – | 243 |
| Gasoline (A-76) | – | 256 |
| PVC linoleum (TU 21-29-76-79) | 200 | 270 |
| Ethyl acetate | – | 330 |
| Fiberglass | 640 | 340 |
| PVC film grade PDO-15 | 640 | 400 |
| Mipora | – | 400 |
| Fabric-based linoleum | – | 469 |
| Cyclohexane | – | 470 |
| Film brand PDSO-12 | 820 | 470 |
| Polyester fiberglass sheet | – | 475 |
| Polyester fiberglass "Sinplex" | – | 520 |
| Toluene | – | 562 |
| Diesel fuel | – | 620 |
| Polystyrene foam brand PPU-316m | – | 757 |
| High pressure polyethylene PEVF | 1930 | 790 |
| Rubber (TU 38-5-12-06-68) | 1680 | 850 |
| Polyethylene | 1290 | 890 |
| Expanded polystyrene PS-1 | – | 1048 |
| Expanded polystyrene PS-1 + 3% decabrom and phenyloxide | – | 1219 |
| PVC-9 foam | 2090 | 1290 |
Determination method
The determination of the smoke generation coefficient, and accordingly the smoke-forming ability of combustible building materials, is carried out in accordance with the requirements of clause 4.18 of GOST 12.1.044-89. The essence of the method for determining the smoke generation coefficient is to determine the optical density of the smoke formed during the combustion or smoldering of a known amount of the test substance or material distributed in a given volume. In other words, the weakening of illumination as light passes through a smoky space is photometrically recorded.
1 – combustion chamber; 2 – sample holder; 3 – quartz glass window; 4, 7 – purge valves; 5 – light receiver; 6 – measurement chamber; 8 – quartz glass; 9 – light source; 10 – safety membrane; 11 – fan; 12 – guide visor; 13 – pilot burner; 14 – liner; 15 – electric heating panel
The figure shows a diagram of the installation for determining the smoke generation coefficient. The combustion chamber with a capacity of 3 × 10 -3 m 3 is made of stainless steel sheet with a thickness of 2.0 ± 0.1 mm. It has upper and lower openings with a cross-section of 30×160 mm, connecting it to the smoke chamber. On the side surface of the combustion chamber there is a quartz glass window for observing the sample during testing. The combustion chamber contains a sample holder and a closed electric heating panel mounted on the upper wall of the chamber at an angle of 45° to the horizontal. The sample holder is made in the form of a frame measuring 100x100x10 mm and is mounted on the chamber door at a distance of 60 mm from the panel parallel to its surface. An asbestosite liner is installed in the holder, in the center of which there is a recess for placing the sample. A gas burner is installed above the sample holder. When testing materials in combustion mode, the burner flame touches the surface of the top of the sample.
The smoke chamber measuring 800x800x800 mm is made of stainless steel sheet. The inner walls of the chamber are covered with black paper. In the upper wall and bottom of the chamber there are holes for purge return valves, an illuminator and a safety membrane. Inside the chamber there is a device for vertical movement of the photocell and a two-blade fan for mixing the smoke.
Tests are carried out in two modes: thermal-oxidative decomposition (smoldering) and flame combustion. The thermal-oxidative decomposition (smoldering) mode is ensured by heating the sample surface to 400 °C, with a heat flux density of 18 kW/m2. Materials whose heat resistance is above 400 °C are tested when heated to 600 °C, the heat flux density is 38 kW/m2. In all cases, materials shall not spontaneously ignite when tested. The flame combustion mode is ensured by using a gas burner and heating the surface of the sample to 750 °C, with a heat flux density of 65 kW/m2. To measure the heat flux density, a metal calorimetric type sensor is used.
When setting up the installation, the voltage supplied to the electric heating panel is determined to ensure the specified test modes. To do this, insert an insert into the holder with control sample made of asbestos cement (40x40x10 mm), in the center of which a thermocouple is fixed. The combustion chamber door is closed and voltage is applied to the coils of the electric heating panel. A potentiometer is used to control stabilized heating conditions.
When testing in the flame combustion mode, insert an insert with an asbestos-cement sample into the holder, close both chambers, and apply the voltage selected for this mode to the coils of the electric heating panel. After the panel reaches stabilized heating conditions, turn on the illuminator, measuring device lux meter, mixing fan. Then the combustion chamber is opened, the liner with the asbestos-cement sample is removed, the gas burner is lit, and the chamber is closed. Purge the smoke chamber for 1 minute. The illuminator is adjusted by diaphragms, setting the illumination to 100 lux, and the diameter of the light beam equal to the diameter of the photosensitive surface of the photocell. The prepared sample of the test material is placed in a liner at room temperature, the combustion chamber door is opened, the liner is inserted into the holder without delay and the door is closed. The duration of the test is determined by the time it takes to reach the minimum illumination, but not more than 15 minutes.
When testing in smoldering mode, do not ignite the gas burner, install an insert with an asbestos-cement sample, and apply the appropriate voltage to the electric heating panel. The testing procedure is similar to that established for the flame combustion mode. Five samples of material are tested in each mode. Based on the results of each test, the smoke generation coefficient D is calculated T max by formula:
D tmax = (V / L× m) ln(E / Emin),
V– capacity of the smoke chamber, m3;
L– length of the light path in a smoke-filled space, m;
T– mass of the sample of the material under study, kg;
In(E/Emin)– optical density of smoke;
E / Emin– initial and minimum illumination, respectively, lux.
For each series of tests, the arithmetic mean of at least five values of the smoke generation coefficient is calculated. The final result is taken highest value of two arithmetic averages.
Protocol for determining the smoke coefficient can be downloaded.
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