Substances and materials belong to the group. Classification of substances and materials by fire hazard

To determine the likelihood of a flame occurring, the flammability of substances and various materials is of primary importance. This characteristic defines the category fire danger structures, premises, production; allows you to choose the right means to eliminate outbreaks.

The flammability group of all material components of an object determines the success of fire fighting and minimizes the likelihood of casualties.

Features of various substances

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

If a substance can burn, the flammability group G1 is more optimal for fire safety than G3 or G4.

Has flammability great importance for finishing, heat-insulating, building materials. On its basis, the fire hazard class is determined. So, plasterboard sheets have flammability group G1, stone wool - NG (does not burn), and insulating polystyrene foam belongs to flammability group G4, and the use of plaster helps reduce its fire hazard.

Gaseous substances

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

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

Liquid

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

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

Solid

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

Classification

The intensity of the combustion process and the conditions under which it occurs determine the likelihood of a fire intensifying and an explosion occurring. The outcome of the incident depends on the totality of the properties of the feedstock.

General division

According to the national fire and explosion hazard standard, substances and various materials made 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 oxidizing agents, with each other, and with water. Consequently, some members of the group pose a fire hazard under certain conditions.

Compounds that are difficult to combust include those that burn when ignited in air. As soon as the source of fire is eliminated, the burning stops.

Under certain conditions, flammable substances ignite on their own or in the presence of a fire source and continue to burn intensely.

The classification of flammability of construction raw materials and products is discussed in a separate updated standard. National construction standards 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.

Group 1 includes products in which the temperature inside the oven increases by no more than 50 ℃. The reduction in sample mass 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 be more than 3.0 MJ/kg.

Flammability classes

Combustible materials are examined according to similar criteria and are divided into 4 groups or classes, which are designated 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 released with smoke;
• degree of size reduction;
• amount of weight reduction;
• flame retention time without a combustion source.

G1 refers to a group of materials with a smoke temperature not exceeding 135 ℃. The loss of length is 65%, weight loss is 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 loss of length is 85%, weight loss is 50%. Self-combustion lasts no more than 30 seconds.

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

The G4 flammability group includes materials with a smoke temperature exceeding 450 °C. Loss of length exceeds 85%, weight loss – more than 50%. Self-combustion lasts more than 300 seconds.

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

• weak;
• moderately;
• Fine;
• highly flammable materials.

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

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

Class confirmation

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

If the product consists of several layers, the standard requires testing for the flammability of each layer.

Determinations of flammability are carried out on special equipment. If it turns out that one of the components is highly flammable, then this status will be assigned to the product as a whole.

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

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

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

At the end of the procedure, the sample along with the holder is removed from the oven, cooled in a desiccator, weighed and measured, assigning them to the flammability group NG, G1, and so on.

Flammability test method

All Construction Materials, including finishing, facing, paint and varnish types of coatings, regardless of homogeneity or multi-layering, are examined for flammability using a single method.

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

The samples are then kept at room temperature and normal ambient humidity for at least 72 hours, weighing periodically. Aging should be stopped when constant weight is reached.

The installation has a standard design and consists of a combustion chamber, an air supply system and the removal of released gases.

The samples are placed in the chamber one by one, measurements are taken, weight loss, temperature and amount of gaseous products released, and burning time without a flame source are recorded.

By analyzing all the obtained indicators, they determine the level of flammability of the material and its belonging to a certain group.

Application in construction

When constructing buildings, several different types building materials: structural, insulating, roofing, finishing with different purposes and loads. All products must have certificates available and be presented to potential buyers.

You should familiarize yourself with the parameters characterizing safety in advance and know exactly what each abbreviation and numbers can mean. The law requires the use of only materials of flammability group G1 or NG for the frames of building ceilings.

Based on flammability, substances and materials are divided into three groups: non-flammable, slow-burning and flammable.

Non-flammable (hard to burn) - substances and materials that are not capable of burning in air. Non-flammable substances can be fire and explosion hazards.

Low-flammability (hard-to-burn) - substances and materials capable of burning in air when exposed to an ignition source, but not capable of burning independently after its removal.

Flammable (combustible)- substances and materials capable of spontaneous combustion, as well as ignite when exposed to an ignition source and burn independently after its removal.

All flammable 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. Flammable gases include individual substances: ammonia, acetylene, butadiene, butane, butyl acetate, hydrogen, vinyl chloride, isobutane, isobutylene, methane, carbon monoxide, propane, propylene, hydrogen sulfide, formaldehyde, as well as vapors of flammable and combustible liquids.

Flammable liquids (flammable liquids) - substances capable of burning independently after removal of the ignition source and having a flash point not higher than 61 ° C (in a closed crucible) or 66 ° (in an open crucible). 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, ethyl alcohol, as well as mixtures and technical products gasoline, diesel fuel, kerosene, white alcohol, solvents.

Flammable liquids (FL) - substances capable of burning independently after removal of the ignition source and having a flash point above 61° (in a closed crucible) or 66° C (in an open crucible). 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 oil, vaseline, castor oil.

Combustible dust(/77) - solid substances in a finely dispersed state. Combustible dust in the air (aerosol) is capable of forming explosive

3 Classification of premises according to fire safety

In accordance with the “All-Union Standards of Technological Design” (1995), buildings and structures in which production is located are divided into five categories (Table 5).

Category A: shops for the processing and use of metallic sodium and potassium, oil refining and chemical production, warehouses for gasoline and cylinders for flammable gases, premises for stationary acid and alkaline battery installations, hydrogen stations and etc.

Construction Decoration Materials According to their flammability, they are divided into three main groups:

Non-combustible materials- Materials that, under the influence of an ignition source (sparks, fire, electric current, high temperature, chemical reaction, etc.) do not ignite or burn (natural and artificial inorganic materials - stone, concrete, reinforced concrete, etc.);

Difficult to combustible materials- Materials that burn under the influence of ignition sources but are incapable of full independent combustion (asphalt concrete, plasterboard, wood impregnated with antipyrites agents, fiberglass, fiberglass, etc.);

Combustible materials- Materials and substances that will remain burning after removal of the ignition source.

Use of non-combustible materials

Non-combustible materials are used in construction and repair for finishing floors, partitions, walls and ceilings of buildings and premises, as well as for cladding facades. The main characteristic of these materials is their resistance to high temperatures.

The INFRACHIM company offers consumers a wide range of innovative non-combustible building materials that have successfully passed all laboratory studies and tests and are confirmed by all necessary certificates and sanitary and epidemiological reports.

TPK INFRACHIM materials can be used in crowded places; they are environmentally friendly materials that are absolutely safe for humans and animals. They do not emit poisonous or toxic substances when heated and have a number of advantages over competitors' products.

Non-combustible materials and their features

The non-flammable materials offered by our company are easy to use, reliable and durable. These products have low indicators for such parameters as change in shape in a wet state, water absorption, change in size after heating, thermal conductivity of the material, and high indicators for the following characteristics: strength and bending in a dry/moisture-saturated state, impact strength, tensile strength , density. The materials, as a rule, are lightweight, which makes them easy to transport and install. Most materials have a perfectly smooth surface, both on the inside and outside.

Non-combustible materials are intended for the production of construction and finishing works indoors and outdoors. They are used for finishing work on almost any building, production premises, hotels, restaurants, hostels, water parks, administrative buildings, etc., etc.

With the help of non-combustible finishing materials, it is possible to carry out external cosmetic work, i.e. finishing of external walls, facades, pediments, cornices, columns, etc. In addition, the products offered are ideal as a basis for laying metal tiles or soft roofs. These materials are quite hard, which allows them to have good heat-insulating and sound-proofing qualities. They received wide application when installing ventilated building facades.

Non-combustible finishing materials have a relatively low weight, which makes them easy to transport without the use of special expensive equipment, and also to be installed by finishing crew workers. They will keep their appearance and will last for many years.

A short excursion into history:

About the cause of fires in the Middle Ages, for example, the same thing was always said: “by chance” and “by the will of God.” The fact that fire was associated with the wrath of God is extremely characteristic of medieval consciousness. Medieval people had very little knowledge about the world around them, but thanks to this naivety and lack of education, their lives were full of miracles.

Today our knowledge is sufficient not only to determine the causes of the fire, but also to, if not prevent it (“the will of chance” is still relevant today), then at least optimize its elimination and minimize the destructive consequences and do not rely on a miracle, but create it yourself.

A common cause of fire is a short circuit power cable and its fire, which quickly spreads along the cable route. Imagine a typical industrial enterprise. If a fire spreads at a temperature of 500 degrees, softening and collapse of seemingly strong metal structures can occur in a matter of minutes. And even concrete cannot withstand temperatures of 1000 degrees. That is, the task is to prevent the spread of fire if it has already appeared.

The cause of the fire at the Ostankino TV tower was the excess of the permissible load on the feeders - the cables transmitting the signal high power from the equipment to the antenna, - excessive load caused overheating and fire of the cables inside the tower. The total damage from the fire at the Ostankino TV tower is estimated at hundreds of millions of dollars, and the moral damage to television viewers who were left “blind” and deprived of a daily dose of information is almost impossible to assess. What could stop the spread of fire if a fire did occur? Miracle? No! Non-flammable polymer materials.

Many countries have already adopted special restrictions on the use of flammable fuels. polymer materials in civil and industrial construction, in production and operation Vehicle(airplanes, cars, buses, trolleybuses, trams, railway cars, ships), at power plants and in electrical networks, in the space and cable industries. So, reducing the flammability and combustibility of polymers, creating fireproof materials is a pressing problem for polymer chemistry. This task is complicated by another urgent requirement of our time - the environmental friendliness of fire retardant additives - fire retardants.

Fire retardants prevent the combustion of polymer materials and are among the most important components of plastics. When polymer materials burn, complex physical and chemical processes occur inside and on the surface of the condensed phase, as a result of which the polymer is converted into combustion products heated to a high temperature.

Features of storage of non-combustible materials

These materials should be stored in dry rooms with normal humidity levels. Subject to these basic storage conditions, the products will perfectly retain their appearance and last for many years.

Regarding the supply of non-combustible materials, please contact the company's sales department by contact numbers.

Refractory substances and materials

"...2) low-flammability - substances and materials that can burn in air when exposed to an ignition source, but are unable to burn independently after its removal;..."

Source:

Federal Law of July 22, 2008 N 123-FZ (as amended on July 10, 2012) “on fire safety requirements”

Official terminology.

Akademik.ru.

2012. See what “Hardly flammable substances and materials” are in other dictionaries:

Low-flammability (hard-to-burn) substances and materials- – substances and materials capable of burning in air when exposed to an ignition source, but not capable of burning independently after its removal. [GOST 12.1.044 89] Term heading: Building materials Encyclopedia headings: Abrasive... ... Construction Materials

- Terms of the heading: Building materials Ceresit cx Conlit Nordic green plus Thermasheet Reinforced cement or steel fiber composite concrete White soot ... Encyclopedia of terms, definitions and explanations of building materials

Fire safety Official terminology

- This article should be Wikified. Please format it according to the rules for formatting articles... Wikipedia Fire-hazardous production facilities are understood as facilities where: a) flammable, combustible and low-flammable liquids, solid flammable and low-flammable substances and... ... are used (produced, stored, processed)

Fire- This term has other meanings, see Fire (meanings). Fire fighting... Wikipedia Fire safety- Fire safety is the state of protecting individuals, property, society and the state from fires. "

Fire safety"an illiterate phrase that comes up to mean "fire safety." Contents 1... ...Wikipedia COMBUSTION

- An exothermic reaction occurring under conditions of its progressive self-acceleration. Based on flammability, substances and materials are divided into three groups: non-flammable (non-combustible) substances and materials that are not capable of burning in air. Non-flammable substances... ... Comprehensive provision of security and anti-terrorist protection of buildings and structures

Rubber crumb- the ability of a substance, material, product to burn independently. According to G., substances, materials, products, and structures are divided into: 1) flammable substances capable of spontaneous combustion after removal of the ignition source; 2) low-flammability capable of... ... Encyclopedia of technology

flammability- flammability the ability of a substance, material, product to burn independently. According to G., substances, materials, products, structures are divided into: 1) flammable capable of spontaneous combustion after removal of the ignition source;... ... Encyclopedia "Aviation"

Combustible substances and materials are divided into three groups based on flammability:

· highly flammable;

· substances of “medium flammability”;

· flame retardant.

Flammable– flammable substances of increased fire hazard, which, when stored in outdoors or indoors are capable of igniting without preheating upon short-term (up to 30 s) exposure to a low-energy ignition source (from a match flame, spark, cigarette, heating of electrical wiring).

To flammable gases include almost all flammable gases, for example, H 2, NH 4, CO, C 3 H 8, natural gas and etc.).

For flammable liquids(flammable liquids) include flammable liquids with flash t. not > 61 0 C in a closed crucible (c.c.) or 66 0 C in an open crucible (o.c.), flammable liquids can be divided into three groups according to fire hazard:

1. especially dangerous;

2. constantly dangerous;

3. dangerous at elevated temperatures.

1.To especially dangerous flammable liquids include, for example, acetone C 2 H 6 O, gasoline - B70, isopentane C 5 H 12, diethyl ether C 4 H 10 O, having t flash. not > 18 0 C (w.t.) or 13 0 C (b.t.). In hot weather, the pressure inside the vessel increases; if the seal is broken, vapors of these liquids can spread over a considerable distance from the vessel, causing a fire.

2. Constantly dangerous flammable liquids are, for example, benzene C 6 H 6, toluene C 7 H 8, ethyl alcohol C 2 H 5 OH, dioxane C 4 H 8 O 2, ethyl acetate C 4 H 8 O 2 with t flash. from –18 0 to +23 0 (w.t.) or from –13 0 to 27 0 (b.t.) are characterized by the ability to form an explosive atmosphere in the vapor-air phase of closed vessels.

Table 1.1

Classification of substances and materials by flammability

Not capable of burning in air

Asbestos fabric, asbestos-glass fabric, foam asbestos, metals used in construction, building materials: sand, clay, gravel, cement and products made from them (brick, concrete), etc. Notes to the table 1.1. 1 Spontaneous combustion is a combustion that occurs in the absence of a visible ignition source. For example, oily rags, metal shavings,

sawdust

, yellow phosphorus, vapor of liquid hydrogen phosphorous P 2 H 4 .

2 Wood mainly consists of fiber (C 6 H 10 O 5) n.

5 3 Rubber is an unsaturated hydrocarbon (C 5 H 8)x, where x = 1000...3000. 4 Rubber - rubber after mixing with sulfur, subjected to vulcanization (heating to a certain temperature). Stearic acid C 18 H 36 O 2 (or C 17 H 35 COOH) – flammable solid –

component

lard

6 Petroleum products: gasoline, kerosene, naphtha, diesel fuel, lubricating oils, fuel oil, etc.

7 Alcohols: methyl CH 4 O, ethyl C 2 H 6 O (C 2 H 5 OH), n-propyl C 3 H 8 O; n-butyl C 4 H 10 O; n-amyl C 5 H 12 O, etc.

10 Liquid hydrocarbons: saturated (alkanes: pentane C 5 H 12, hexane C 6 P 14, etc.); unsaturated (alkenes: 1-pentene C 5 P 10, 1-hexene C 6 H 12, 1-octene C 8 H 16, etc.); cyclic (naphthenes: cyclopentane (CH 2) 5, cyclooctane (C 2 H 8), etc.; aromatic (benzene C 6 H 6, toluene C 7 H 8, etc.).

11 Gaseous hydrocarbons: saturated (alkanes: methane CH 4, ethane C 2 H 6, propane C 3 H 3, butane C 4 H 10, etc.); unsaturated (ethylene C 2 H 4, propylene C 3 H 6, butylene C 4 H 8, etc.).

These features impose additional safety requirements for their transportation, storage and use.

3. Hazardous at elevated temperatures flammable liquids include, for example, white alcohol C 10.5 N 21.3 lighting kerosene, chlorobenzene C 6 H 5 Cl, solvent, turpentine, etc., having a flash point above 23 0 ... 61 0 (w.t.) or 27 0 …66 0 (b.t.). In hot shops (at elevated temperatures), vapors of these liquids can ignite in the air; at normal temperatures (~ 20 0 C), these substances ignite only in the presence of an ignition source.

Highly flammable solids (materials): celluloid, polystyrene, wood shavings, peat stoves (ignite from the flame of a match, alcohol lamp, gas burner).

Medium flammability: wood, coal, paper in bundles, fabric in rolls (requires an ignition source with high energy capable of heating to ignition temperature).

Flammable: urea (urea) CH 4 ON 2, getinax grade B (pressed paper treated with resole-type synthetic resin), wood after fire-retardant treatment, polyvinyl chloride board.

A special class of flammable substances are pyrophoric and explosive substances.

Pyrophoric - capable of self-ignition in open air (liquid phosphorus, liquid hydrogen phosphide P 2 H 4, etc.).

Explosives are substances capable of rapid exothermic transformation with the formation of compressed gases (explosion) without the participation of atmospheric oxygen (nitroglycerin, nitromethane, trinitrotuluene C 6 H 2 (N 2 O) 3 CH 3, ammonium nitrate NH 4 NO 3).