What building materials are non-combustible. What is the flammability group G1
"Fire safety of buildings and structures" on the fire-technical classification of building materials, as well as the provisions of other regulatory documents on fire safety, to which this document refers.
For non-combustible building materials, other indicators of fire hazard are not determined or standardized.
flammability- the ability of substances and materials to ignite.
ignition - The initiation of flame combustion by an ignition source, characterized by a sustained flame combustion in this standard test.
ignition time- the time from the start of the test to the onset of a stable flame combustion.
stable flame combustion- combustion, continuing until the next exposure of the sample to the flame from the ignition source.
Radiant heat flux acting on a unit of sample surface.
The minimum value of the surface heat flux density at which a stable flame combustion occurs.
flame spread- the spread of flame combustion over the surface of the sample as a result of the impact specified in this standard;
surface heat flux density (PPTP)- radiant heat flux acting on a unit of sample surface;
critical surface heat flux density (KPPTP)- the magnitude of the heat flux at which the flame propagation stops.
In clause 5.7 of SNiP 21-01-97 * it is established that combustible building materials are divided into three groups according to their smoke-forming ability:
D1 (with low smoke-generating ability);
D2 (with moderate smoke-generating ability);
D3 (with high smoke-generating ability).
Groups of building materials for smoke-generating ability are established in accordance with GOST 12.1.044-89 "Occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination". This document contains the following provisions regarding the smoke production coefficient.
Smoke production coefficient- an indicator characterizing the optical density of smoke formed during flame combustion or thermo-oxidative destruction (smoldering) of a certain amount of a solid (material) under special test conditions.
The value of the smoke production coefficient should be used to classify materials according to their smoke generating ability. There are three groups of materials:
with low smoke-generating ability - smoke production coefficient up to 50 m2kg-1 inclusive;
with a moderate smoke-generating ability - the coefficient of smoke production of St. 50 to 500 m2kg-1 inclusive;
with a high smoke-generating ability - the coefficient of smoke production of St. 500 m2kg-1.
The value of the smoke production coefficient should be included in the standards or specifications for solids and materials.
In accordance with clause 5.8 of SNiP 21-01-97 *, combustible building materials are divided into four groups according to the toxicity of combustion products:
T1 (low hazard);
T2 (moderately dangerous);
T3 (highly hazardous);
T4 (extremely dangerous).
Groups of building materials for the toxicity of combustion products are established in accordance with GOST 12.1.044-89 "Occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination". The mentioned document in relation to the toxicity index of combustion products of polymeric materials provides the following.
The indicator of toxicity of combustion products is the ratio of the amount of material to a unit volume of a closed space in which gaseous products formed during the combustion of the material cause the death of 50% of the experimental animals.
The value of the toxicity indicator of combustion products should be used for a comparative assessment of polymeric materials, and also included in the technical specifications and standards for finishing and heat-insulating materials. The classification of materials according to the value of the toxicity index of combustion products is given in the table.
The essence of the method for determining the toxicity indicator consists in burning the material under study in a combustion chamber at a given heat flux density and revealing the dependence of the lethal effect of gaseous combustion products on the mass of the material per unit volume of the exposure chamber.
The table, which is established in GOST 12.1.044-89, is reproduced in table 2 of the appendix to the commented Law (see the commentary to the specified table).
11. In accordance with Part 11 of the commented article, classes of fire hazard of building materials are distinguished depending on the groups of fire hazard of building materials. These classes - KM0, KM1, KM2, KM3, KM4 and KM5 - are shown in Table 3 of the Appendix to the commented Law. It should be noted that the allocation of these classes is an innovation, since earlier in the normative documents on fire safety (first of all, in SNiP 21-01-97 * "Fire safety of buildings and structures") only groups of fire hazard of building materials were singled out.
12. At ch. 12
Classification of building materials
By origin and purpose
By origin, building materials can be divided into two groups: natural and artificial.
Natural refers to such materials that occur in nature in finished form and can be used in construction without significant processing.
Artificial they call building materials that do not occur in nature, but are manufactured using various technological processes.
By designation, building materials are divided into the following groups:
Materials intended for the construction of walls (brick, wood, metals, concrete, reinforced concrete);
Binder materials (cement, lime, gypsum) used to obtain non-fired products, masonry and plaster;
Thermal insulation materials (foam and aerated concrete, felt, mineral wool, polystyrene, etc.);
Finishing and facing materials (rocks, ceramic tiles, various types of plastics, linoleum, etc.);
Roofing and waterproofing materials (roofing steel, tiles, asbestos-cement sheets, slate, roofing felt, roofing material, isol, brizol, poroizol, etc.)
NON-FLAMMABLE BUILDING MATERIALS
Natural stone materials. Building materials obtained from rocks by using only mechanical processing (crushing, sawing, splitting, grinding, etc.) are called natural stone materials. They are used for the construction of walls, flooring, staircases and building foundations, cladding of various structures. In addition, rocks are used in the production of artificial stone materials (glass, ceramics, thermal insulation materials), as well as as raw materials for the production of binders: gypsum, lime, cement.
The effect of high temperatures on natural stone materials. All natural stone materials used in construction are non-combustible, however, under the influence of high temperatures in stone materials, various processes occur, leading to a decrease in strength and destruction.
The minerals included in stone materials have different coefficients of thermal expansion, which can lead to the appearance of internal stresses in the stone during heating and the appearance of defects in its internal structure.
The material undergoes a modification transformation of the crystal lattice structure associated with an abrupt increase in volume. This process leads to cracking of the monolith and a drop in the strength of the stone due to large temperature deformations resulting from sudden cooling.
It should be emphasized that all stone materials irreversibly lose their properties under the influence of high temperatures.
Ceramic products. Since all ceramic materials and products in the process of their production are fired at high temperatures, the repeated action of high temperatures under fire conditions does not significantly affect their physical and mechanical properties if these temperatures do not reach the softening (melting) temperatures of the materials. Porous ceramic materials (ordinary clay brick, etc.), obtained by firing, which is not brought to sintering, can succumb to moderately high temperatures, as a result of which some shrinkage of structures made of them is possible. The impact of high temperatures in a fire on dense ceramic products, which are fired at temperatures of about 1300 ° C, practically does not have any harmful effect, since the temperature on a fire does not exceed the firing temperature.
Red clay brick is the best material for fire walls.
Metals. In construction, metals are widely used for the construction of frames for industrial and civil buildings in the form of rolled steel profiles. A large amount of steel is used for the manufacture of reinforcement for reinforced concrete. Steel and cast iron pipes, roofing steel are used. In recent years, lightweight building structures made of aluminum alloys have found more and more widespread use.
Behavior of steels in case of fire. One of the most characteristic features of all metals is the ability to soften when heated and restore their physical and mechanical properties after cooling. In a fire, metal structures very quickly warm up, lose strength, deform and collapse.
Reinforcing steels will behave worse in fire conditions (see the "References" section), which are obtained by additional hardening by means of heat treatment or cold broaching (work hardening). The reason for this phenomenon lies in the fact that additional strength of these steels is obtained due to the distortion of the crystal lattice, and under the influence of heating, the crystal lattice returns to an equilibrium state and the increase in strength is lost.
Aluminum alloys. The disadvantage of aluminum alloys is a high coefficient of thermal expansion (2-3 times higher than that of steel). When heated, there is also a sharp decrease in their physical and mechanical parameters. The tensile strength and yield strength of aluminum alloys used in construction are approximately halved at a temperature of 235-325 ° C. Under fire conditions, the temperature in the room volume can reach these values in less than one minute.
Materials and products based on mineral melts and products from glass melts. This group includes: glass materials, products from slag and stone casting, sitalls and slag glass, sheet window and display glass, patterned, reinforced, sun- and heat-shielding, facing glass, glass profiles, double-glazed windows, glass carpet-mosaic tiles, glass blocks, etc. ...
Behavior of materials and products from mineral melts at high temperatures. Materials and products made from mineral melts are non-flammable and cannot contribute to the development of a fire. Exceptions are materials based on mineral fibers containing a certain amount of organic binder, such as thermal insulation mineral slabs, silica slabs, slabs and roll mats made of basalt fiber. The flammability of such materials depends on the amount of binder introduced. In this case, its fire hazard will be determined mainly by the properties and the amount of polymer in the composition.
Window glass does not withstand prolonged thermal loads in a fire, but with slow heating it may not collapse for a long time. Glass breakage in skylights begins almost immediately after the flame begins to touch its surface.
Structures made of tiles, stones, blocks based on mineral melts have a significantly higher fire resistance than sheet glass, since, even when cracked, they continue to bear the load and remain sufficiently impervious to combustion products. Porous materials from mineral melts retain their structure almost up to the melting temperature (for foam glass, for example, this temperature is about 850 ° C) and for a long time perform heat-shielding functions. Since porous materials have a very low coefficient of thermal conductivity, even at the moment when the side facing the fire melts, deeper layers can perform heat-shielding functions.
FLAMMABLE BUILDING MATERIALS
Wood... When wood is heated to 110 ° C, moisture is removed from it, and gaseous products of thermal destruction (decomposition) begin to evolve. When heated to 150 ° C, the heated wood surface turns yellow, the amount of emitted volatile substances increases. At 150-250 ° C, the wood becomes brown due to charring, and at 250-300 ° C, the wood decomposition products are ignited. The self-ignition temperature of wood is in the range of 350-450 ° C.
Thus, the process of thermal decomposition of wood proceeds in two phases: the first phase - decomposition - is observed when heated to 250 ° C (to the ignition temperature) and proceeds with heat absorption, the second, the combustion process itself, proceeds with the release of heat. The second phase, in turn, is subdivided into two periods: combustion of gases formed during the thermal decomposition of wood (flame phase of combustion), and combustion of the resulting charcoal (smoldering phase).
Bituminous and tar materials. Building materials, which include bitumen or tar, are called bituminous or tar.
Ruberoid and tarpaulin roofs can ignite even from low-power sources of fire, such as sparks, and continue to burn on their own, emitting a large amount of thick black smoke. When burning, bitumen and tar soften and spread, which significantly complicates the situation on a fire.
The most common and effective way to reduce the flammability of roofs made of bituminous and tar materials is to sprinkle them with sand, backfill with a continuous layer of gravel or slag, and cover with any non-combustible tiles. Some fire-retardant effect is provided by coating roll materials with foil - such coatings do not ignite when exposed to sparks.
It should be borne in mind that rolled materials made with bitumen and tar are prone to spontaneous combustion when rolled up. This circumstance must be taken into account when storing such materials.
Polymeric building materials. Polymeric building materials (PSM) are classified according to various criteria: the type of polymer (polyvinyl chloride, polyethylene, phenol-formaldehyde, etc.), production technologies (extrusion, casting, roll-calender, etc.), purpose in construction (structural, finishing, floor materials , heat and sound insulation materials, pipes, sanitary-technical and molded products, mastics and adhesives). All polymer building materials are highly flammable, smoke-generating and toxic.
New class of LINOLEUM KM2 B2, D2, T2, RP1
In July 2012, a long-awaited event took place that introduced major changes to the Federal Law. Now questions like: Non-flammable linoleum, Linoleum G1, Linoleum G1, B1 are NOT RELEVANT ... The main indicators are Linoleum class KM, it can be KM1, KM2, KM3, KM4 and KM5. The fire safety class is determined by such indicators as: Flammability (B2), Smoke-generating capacity (D2), Toxicity (T2), Flame spread (RP1). Linoleum now it is necessary to select only on the basis of the Class KM1, KM2, KM3, KM4, KM5 and it is Important to Remember and Know. Next, we provide a table with old indicators, where the changes to which were made to the law are marked in red.According to the change in the Federal Law (hereinafter FZ No. 117), the application vinyl linoleum KM2 in hospitals, schools and kindergartens, general education institutions have been significantly expanded.
New fire hazard requirements for floor coverings
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Construction fire hazard properties materials |
KM0 | KM1 | KM2 | KM3 | KM4 | KM5 |
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Flammability |
NG | D1 | D1 | G2 | G3 | G4 |
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Flammability |
IN 1 | IN 2(was B1) | IN 2 | AT 3 | ||
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Smoke generating |
D 2(It was D1) | D2 (was D3 +) | D3 | D3 | ||
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Toxicity |
T2(was T1) | T2 | T2 | T4 | ||
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Flame spread |
RP1 | RP1 | RP2(was RP1) | RP2 | RP4 |
HOMOGENEOUS LINOLEUM KM2
| Coating Type | Brand name | Fire indicators | ||
| iQ Monolit iQ Aria iQMelodia iQ Zenith Plus primo Kerama |
Tarkett |
B2, D2, T2, RP1 |
KM2 |
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Horizon |
Sinteros |
B2, D2, T2, RP1 |
KM2 |
In the halls, including kindergartens, educational institutions, hospitals. On escape routes up to 17 floors. (Cannot be laid on staircases and in lobbies of preschool educational institutions, staircases and hospital lobbies, and on staircases and lobbies of buildings over 17 floors) |
HETEROGENEOUS LINOLEUM KM2
| Coating Type | Brand name | Fire indicators | New class of fire hazard |
Permitted scope |
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Acczent universal PrizmaCity ModaWood |
Tarkett |
B2, D2, T2, RP1 |
KM2 |
In the halls, including kindergartens, educational institutions, hospitals. On escape routes up to 17 floors. (Cannot be laid on staircases and in lobbies of preschool educational institutions, staircases and hospital lobbies, and on staircases and lobbies of buildings over 17 floors) |
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Tarkett |
B2, D3, T2, RP1 |
KM3 |
In halls for up to 300 people, in common corridors, halls and foyers in buildings up to 17 floors. (Cannot be used in wards, bedrooms and in kindergartens) |
The indicator of the flammability group is no longer required for linoleum floor coverings (G1, G2, G3, G4)
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Appointment |
The list of required indicators, depending on |
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group |
group |
group |
group |
group |
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Materials for |
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Materials for |
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Roofing |
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Waterproofing |
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Heat insulating |
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Notes: 1. The "+" sign indicates that the indicator should be applied.
2. A "-" sign indicates that the indicator is not applicable.
You can also apply PVC coverings, commercial linoleum, in most premises that are considered evacuation routes.
All you need to know, articles on how to choose flooring
The flammability of substances and various materials is of prime importance to determine the likelihood of a flame appearing. This characteristic determines the category of fire hazard of structures, premises, industries; allows you to choose the right means to eliminate foci.
The flammability group of all material components of the object determines the success of fighting a fire, minimizes the likelihood of casualties.
Features of various substances
It is known that substances can be in various 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, before for fire safety, the most optimal flammability group is G1 than G3 or G4.
Flammability is of great importance for finishing, heat-insulating, building materials. On its basis, the class of fire hazard is determined. So, gypsum plasterboard sheets have a flammability group G1, stone wool - NG (does not burn), and insulating expanded polystyrene belongs to the 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 point of ignition to any distance.
If such a boundary value does not exist, and the gas cannot ignite spontaneously, then it is called non-combustible.
Liquid
Liquids are called flammable if there is a temperature at which they can ignite. If the liquid stops burning in the absence of an external source of heating, then it is called hardly combustible. Non-flammable liquids do not ignite at all in an air atmosphere under normal conditions.
Some liquids (acetone, ether) can flash at 28 ℃ and below. They are classified as especially dangerous. Combustible liquids at 61 ... 66 ℃ and above are classified as flammable (kerosene, white spirit). The tests are carried out in an open and closed crucible.
Solid
In the field of construction, the most relevant is the definition of the flammability 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 for its course determine the likelihood of an intensification of a fire, an explosion. The outcome of an 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-flammable;
- difficult to burn;
- flammable.
They cannot burn in air, which does not exclude interaction with oxidants, with each other, and water. Consequently, some members of the group present a fire hazard under certain conditions.
Compounds that are difficult to burn are those that burn when ignited in air. As soon as the source of the fire is eliminated, the combustion ceases.
Combustible substances under certain conditions ignite on their own or in the presence of a fire source, continue to burn intensively.
The flammability classification of construction materials and products is considered in a separate updated standard. National building codes take into account the categories of all types of products used in work.
According to this classification, non-combustible building materials (NG) 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 decrease in the mass of the sample does not exceed 50%. The flame does not burn at all, and the heat released 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 for up to 20 seconds, the heat of combustion should not exceed 3.0 MJ / kg.
Flammability classes
Combustible materials are examined according to similar criteria, subdivided 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;
- reduction in size;
- the amount of weight reduction;
- flame retention time without a source of combustion.
G1 includes a group of materials with a smoke temperature not exceeding 135 ℃. Loss of length is 65%, weight loss - 20%. The flame itself does not burn. Such construction products are called self-extinguishing.
G2 includes a group of materials with a smoke temperature not exceeding 235 ℃. The length loss is 85%, the weight loss is 50%. Self-burning lasts no more than 30 seconds.
G3 includes materials for which the smoke temperature does not exceed 450 ℃. Loss of length is more than 85%, weight loss is up to half. The flame itself burns for no more than 300 seconds.
The flammability group G4 includes materials with a smoke temperature exceeding 450 ° C. Loss of length exceeds 85%, weight loss - more than 50%. Self-burning lasts more than 300 seconds.
It is permissible to use the following prefixes in the name of each flammability group in ascending order of the digital index:
- weak;
- moderately;
- fine;
- highly flammable materials.
The given indicators of combustibility, along with some other characteristics, must be taken into account when developing project documentation, drawing up 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 checking the flammability of each layer.
Determinations of flammability are carried out on special equipment. If it turns out that one of the components has high flammability, then this status will be assigned to the product as a whole.
The setup for carrying out experimental determinations should be located in a room with room temperature, normal humidity, and no drafts. Bright sunlight or artificial light in the laboratory should not interfere with the reading of the displays.
Before starting the study of the sample, the device is checked, calibrated, and heated. Then the sample is fixed in the holder of the inner cavity of the oven 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 the temperature balance is reached, at which within 10 minutes the changes do not exceed 2 ° C.
At the end of the procedure, the sample together with the holder is taken out of the oven, cooled in a desiccator, weighed and measured, reckoning them to the flammability group 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 tested for combustibility by a single method.
Pre-prepare 12 units of identical samples with a thickness equal to the real 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 discontinued when a constant mass is reached.
The plant has a standard design and consists of a combustion chamber, an air supply and evacuated gases removal system.
The samples are placed in turn in the chamber, measurements are taken, the weight loss, temperature and amount of evolved gaseous products, combustion time without a flame source are recorded.
Analyzing all the indicators obtained, the level of flammability of the material, its belonging to a certain group, is determined.
Application in construction
When erecting buildings, several different types of building materials are used: structural, insulating, roofing, finishing with different purposes and loads. All products must be in stock and presented to potential buyers with certificates.
You should familiarize yourself in advance with the parameters characterizing safety, be firmly aware of what each abbreviation and numbers can mean. The law requires the use of materials of the flammability group G1 or NG for the frames of building ceilings.
According to their combustibility, substances and materials are divided into three groups: non-combustible, hardly combustible and combustible.
Non-flammable (hardly combustible) - substances and materials not capable of burning in air. Non-flammable substances can be fire and explosive.
Flame retardant (hardly combustible) - substances and materials that can burn in the air when exposed to an ignition source, but cannot independently burn after its removal.
Combustible (combustible)- substances and materials that can ignite spontaneously, as well as ignite when exposed to an ignition source and burn independently after removing it.
All combustible substances are divided into the following main groups:
Combustible gases (GG) - substances capable of forming flammable and explosive mixtures with air at temperatures not exceeding 50 ° C. Combustible gases include individual substances: ammonia, acetylene, butadiene, butane, butyl acetate, hydrogen, vinyl chloride, isobutane, isobutylene, methane, carbon monoxide, propane, propylene, hydrogen sulfide, formaldehyde, and vapors of flammable and flammable liquids.
Flammable liquids (FL) - substances that can burn independently after removing the ignition source and have a flash point not higher than 61 ° С (in a closed crucible) or 66 ° (in an open one). These liquids include individual substances: acetone, benzene, hexane, heptane, dimethylforamide, difluorodichloromethane, isopentane, isopropylbenzene, xylene, methyl alcohol, carbon disulfide, styrene, acetic acid, chlorobenzene, cyclohexane, ethyl acetate, ethylbenzene technical products gasoline, diesel fuel, kerosene, white spirit, solvents.
Flammable liquids (FL) - substances that can burn independently after removing the ignition source and have a flash point above 61 ° (in a closed crucible) or 66 ° C (in an open one). Flammable liquids include the following individual substances: aniline, hexadecane, hexyl alcohol, glycerin, ethylene glycol, as well as mixtures and technical products, for example, oils: transformer, vaseline, castor.
Combustible dust(/ 77) - solids in a finely dispersed state. Combustible dust in the air (aerosol) is capable of forming explosive
3 Classification of premises for fire safety
In accordance with the "All-Union Standards for Technological Design" (1995), buildings and structures in which production facilities are located are subdivided into five categories (Table 5).
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Characteristics of substances and materials located (circulating) in the room |
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explosion-hazardous |
Combustible gases, flammable liquids with a flash point of not more than 28 ° C in such an amount that they can form explosive vapor-gas-air mixtures, when ignited, the calculated excess pressure of the explosion in the room is exceeding 5 kPa. Substances and materials that can explode and burn when interacting with water, atmospheric oxygen or one with another in such an amount that the calculated excess pressure of the explosion in the room exceeds 5 kPa. |
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explosive |
Combustible dusts or fibers, flammable liquids with a flash point of more than 28 ° C, flammable liquids in such an amount that they can form explosive dust or vapor-air mixtures, when ignited, the calculated excess pressure of the explosion in the room, exceeding 5 kPa, develops. |
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fire hazardous |
Flammable and hardly combustible liquids, solid combustible and hardly combustible substances and materials that can only burn when interacting with water, air oxygen or one with the other, provided that the premises in which they are available or used do not belong to categories A or B |
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Non-flammable substances and materials in a hot, incandescent or molten state, the processing of which is accompanied by the release of radiant heat, sparks and flames, flammable gases, liquids and solids that are burned or disposed of as fuel |
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Non-combustible substances and materials in a cold state |
Category A: workshops for the processing and use of metallic sodium and potassium, oil refining and chemical industries, warehouses for gasoline and cylinders for combustible gases, premises for stationary acid and alkaline storage systems, hydrogen stations, etc.
