What is Safe Experimental Maximum Clearance (BEMZ)?

Method for determining BEMZ.

Test setup for determining BEMZ:

a - inner chamber.
b - outer chamber.
c - adjusting part (usually a screw).
d - pump (for pumping out explosion products).
e - inlet pipe for the mixture.
f - window.
g - electrode.
h - lower fixed part.
i - upper movable part.

The gas inside the test chamber is ignited. The gap is between the lower fixed part and the upper movable part, the length of the so-called "flame passage" in the chamber is 25 mm. Hot ignited gas passes through the "flame-passage". If the gas passing through the gap ignites the surrounding gas-air medium, then the test is carried out again with a smaller gap. The gap that prevents ignition of the surrounding gas-air environment is called the Safe Experimental Maximum Clearance (SEMZ).

For devices with the type of protection "Flameproof enclosure", the use of BEMZ values ​​\u200b\u200bis not common, since for real operating conditions the maximum working clearance is used depending on the type of gas:

• Propane 0.4 mm.
• Ethylene 0.2 mm.

Objective: get acquainted with the experimental method for determining the size of the extinguishing gap (BEMZ) and the choice of explosion-proof electrical equipment.

Basic concepts

An explosion is a rapid transformation of substances (explosive combustion), accompanied by the release of energy and the formation of compressed gases capable of doing work.

Flash - rapid combustion of a combustible mixture, not accompanied by the formation of compressed gases.

Flash point - the lowest (under special test conditions) temperature of a combustible substance at which vapors and gases are formed above its surface that can flare up from an ignition source, but the rate of their formation is still insufficient for subsequent combustion.

The autoignition temperature is the lowest temperature of a combustible substance at which a sharp increase in the rate of exothermic reactions occurs, ending in the occurrence of fiery combustion.

Flammable liquid (flammable liquid) - a liquid capable of burning independently after the ignition source is removed and having a flash point not higher than 61 ° C (classified as explosive).

Combustible liquid (FG) - a liquid capable of burning on its own after the ignition source is removed and having a flash point above 61 ° C (it is classified as a fire hazard if it is not heated to a flash point or higher).

The lower concentration limit of ignition (LEL) is the minimum concentration of combustible gases, vapors of flammable liquids, dust or fibers in the air, below which an explosion will not occur even if an explosion initiation source occurs.

Safe experimental maximum gap (SEMZ) - the maximum gap between the flanges of the shell, through which the transfer of an explosion from the shell to environment at any concentration of the mixture in air.

In accordance with ONTP 24-86 /I/ all industrial premises for fire and explosion fire hazard are divided into 5 categories - A, B, C, D, D (Table 1). Categories are determined by the magnitude of excess pressure for the most unfavorable conditions in relation to fire or explosion - emergency release of the maximum amount of explosive and flammable substances. Excess explosion pressure is calculated by the formulas:

For combustible gases, vapors of flammable and combustible liquids, consisting of atoms C, H, 0, N, Cl, F, I, Br:

For other chemicals and dusty combustibles

(2)

where: P 0 - initial pressure, kPa; it is allowed to take P 0 \u003d 101 kPa;

P max - maximum explosion pressure of a stoichiometric vapor or gas-air mixture in a closed volume, kPa; in the absence of reference data, it is allowed to take P max \u003d 900 kPa;

m - the maximum possible mass of combustible substances (gases, vapors of liquids, dust) that entered the premises as a result of an accident, kg;

T 0 - initial air temperature, K;

Y CB - free volume of the room, excluding volume technological equipment, m 3 ; it is allowed to take 0.8 of the geometric volume of the room;

K N - coefficient taking into account the leakage of the room and the non-adiabatic nature of the combustion process; it is allowed to take K N =3;

 G - density of gases or vapors of combustible liquids at design temperature, kg/m 3 ;

 B - air density before the explosion at the initial temperature T 0, kg / m 3

C p - specific heat capacity of air, ; it is allowed to take C p =1010 J/(kgK);

C ST - stoichiometric concentration of combustible gases or vapors of combustible liquids with air, at which combustion occurs completely without residue,%;

H T - heat of combustion, J/kg;

Z is the calculated coefficient of participation of combustible substances in the explosion; it is allowed to take the following values ​​Z^

combustible gases, combustible dusts Z=0.5;

Flammable liquid and liquid liquid, heated below the flash point and above Z=0.3l

Flammable liquid and liquid liquid, heated below the flash point, with the possibility of aerosol formation Z=0.3;

the same, in the absence of the possibility of aerosol formation Z=0;

substances and materials capable of exploding and burning when interacting with water, atmospheric oxygen or with each other Z=1.

	Characteristics of substances and materials located (circulating) in the room
Explosive:	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, upon ignition of which the calculated temperature develops in the room overpressure explosion exceeding 5 kPa.
	Substances and materials capable of exploding and burning when interacting with water, atmospheric oxygen or with each other, in such an amount that the calculated overpressure of the explosion in the room exceeds 5 kPa.
	Combustible dusts or fibers, flammable liquids with a flash point of more than 28 ° C in such an amount that they can form explosive dust and vapor-air mixtures, upon ignition of which, an estimated excess explosion pressure of more than 5 kPa develops in the room
Flammable:	Combustible and slow-burning liquids, solid combustible and slow-burning substances and materials (including dust and fibers), substances and materials that can only burn when interacting with water, atmospheric oxygen or with each other, provided that the premises in which they are in stock or in circulation are not in category A or B.
	Non-combustible 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; combustible gases, liquids and solids that are burned or disposed of as fuel.
	Non-flammable substances and materials in a cold state.

Introduction

Substances capable of forming explosive mixtures with air (flammable gases, flammable liquids, combustible dusts) have different physical and chemical properties and fire hazard indicators, which significantly affect both the likelihood of their ignition from certain ignition sources and the explosion parameters .

These metrics include:

heat of combustion;

self-ignition temperature;

minimum ignition energy;

induction period.

They depend on the chemical composition and structure of substances. Therefore, in order to exclude the occurrence of explosion and fire from ignition sources associated with the operation of electrical equipment, it (electrical equipment) must be specially designed for safe use in a specific environment that has certain fire hazard indicators.

In various industries, a large number of explosive substances are used. It is impossible to develop and manufacture explosion-proof electrical equipment for each of these substances. At the same time, it is not economically feasible to use explosion-proof electrical equipment designed for use in the most dangerous conditions in all cases (such equipment is much more expensive).

All this necessitated the classification of explosive mixtures according to their degree of danger.

Thus, the classification of explosive zones into classes alone is not enough for the correct choice of electrical equipment, and when choosing electrical equipment for explosive zones, one should take into account not only the class of the zone, but also the physicochemical properties of explosive mixtures. This requirement is reflected in the Technical Regulations on fire safety requirements:

Article 50 Ways to exclude the conditions of education in combustible environment(or adding to it) sources of ignition

1. The exclusion of the conditions for the formation of sources of ignition in a combustible medium (or introduction into it) must be achieved by one or more of the following methods:

1) the use of electrical equipment corresponding to the class of a fire hazardous and (or) explosive zone, category and explosive mixture group ;

Article 82 Fire safety requirements for electrical installations of buildings and structures

1. Electrical installations of buildings and structures must comply with the class of the fire and explosion hazardous zone in which they are installed, as well as category and group of combustible mixture.

12. Explosion-proof electrical equipment may be used in fire hazardous and non-flammable premises, and in explosive premises - subject to compliance categories and groups of explosive mixtures indoors mind the explosion protection of electrical equipment.

1. Classification of explosive mixtures of gases and vapors with air

Explosive mixtures of gases and vapors with air are classified according to categories and groups . In the PUE, the classification of the VOC is given in accordance with GOST 12.1.011-78. Before the introduction of standards for explosion-proof electrical equipment, the classification of VOS was carried out according to PIVRE (1967) and PIVE (1960)

1.1. Category classification

Explosive mixtures of gases and vapors are divided into categories depending on the magnitude safe experimental maximum clearance (BEMZ) and ratio values minimum ignition currents classified mixture and methane ( MTV ).

BEMZ ( clause 7.3.25 of the EIC ) is the maximum gap between the flanges of the shell, through which the explosion does not transfer from the shell to the environment at any concentration of the mixture in air.

BEMZ is the maximum gap between the two parts of the chamber, consisting of hemispheres with flanges 25 mm long, which excludes the ignition of an external mixture of gas or vapor in air when this mixture is ignited inside the chamber.

1 - inner chamber;

2 - external camera;

3 - micrometric screw;

4 - pump;

5 - viewing windows;

6 - the upper movable part of the inner chamber;

7 - the lower fixed part of the inner chamber;

8 - electrodes between which a spark discharge occurs;

9 - cranes;

10 – flame arrester

Rice. 1 Test setup according to GOST R 51330.2-99

The test setup consists of inner and outer chambers. The outer chamber is equipped with viewing windows. The inner chamber consists of two hemispheres with an annular gap between them. Both chambers are filled with the test mixture at a normal pressure of 0.1 MPa and a temperature of 20 0 C. Ignite the mixture in the inner chamber and the presence or absence of ignition in the outer chamber is judged on the basis of observation through the viewing windows.

BEMZ is determined by gradually reducing the annular gap to such a value that the mixture does not ignite in the outer chamber for any concentration of gas or vapor in air ( GOST R 51330.2-99. Explosion-proof electrical equipment. Part 1. Explosion protection of the "flameproof enclosure" type. Addendum 1. Appendix D . Method for determining the safe experimental maximum clearance ).

The classification of explosive mixtures into categories depending on the BEMZ is given in Table 1

Table 1

According to PIVE and PIVRE		According to the PUE		Substances
	Critical gap, mm		BEMZ, mm
				mine methane
	More than 0.65 to 1	II A	More than 0.9	Industrial gases and vapors
	More than 0.35 to 0.65	II B	More than 0.5 to 0.9
	≤ 0,35	II C	≤ 0,5

Minimum igniting current (MW) - current in the electrical circuit, causing ignition of an explosive mixture with a probability of 10 -3 when tested using a sparking mechanism ( according to GOST R 51330.4-99 ).

The classification of explosive mixtures by categories depending on the ratio of the MW of the classified mixture and methane according to GOST R 51330.11-99 is given in the table:

To classify most WSIs into categories, it is sufficient to use one of the indicators (BEMZ or MW). Both indicators must be determined in the following cases:

If the MW is from 0.45 to 0.5 or from 0.8 to 0.9, it is necessary to additionally determine the BEMZ;

If BEMZ is from 0.5 to 0.55, it is necessary to additionally determine the MW.

1.2. Group classification

The basis of the WOC classification by groups put mixtures. The lower this temperature, the more likely the ignition of the mixture under all other conditions. equal conditions compared to a mixture with a higher auto-ignition temperature.

Self-ignition temperature of an explosive gas mixture - the lowest ambient temperature at which, under special test conditions, self-ignition of an explosive gas mixture is observed.

The classification of explosive mixtures by groups is given in the table:

VOS Group	Temperature self-ignition, C		VOS Group	Temperature self-ignition, C
By PIVE		According to PUE and PIVRE
	Above 450			>450
	Above 300 to 450			Above 300 to 450
	Above 175 to 300			Above 200 to 300
	Above 120 to 175			Above 135 to 200
				Above 100 to 135
			T6*	≤ 100

*Group T6 is introduced by the PUE, and is not applied when classifying according to the PIVRE.

1.3. The procedure for determining the category and group of VOS

When using the table. 1 GOST R 51330.19-99 it is necessary to find in it the substance that forms the WOC, its BEMZ and T St. . Further, according to the characteristics found, the category and group of VOS are determined using tables 7.3.1 and 7.3.2 of the EMP.

When using the table. 7.3.3 of the PUE, it is enough to find in it the substance that forms the VOC, and determine the category and group of the mixture in columns 1 and 2 of the corresponding line.

2. Classification of explosive dust atmospheres

Definitions used in the classification of explosive dust atmospheres:

Dust - an environment that includes both combustible dust and combustible flying particles.

combustible dust - solid particles with a nominal size of 500 µm or less, which can burn or smolder in air, form an explosive mixture with air at atmospheric pressure and normal temperature.

Explosive dust environment - a mixture with air, under atmospheric conditions, of combustible substances in the form of dust or flying particles, in which, after ignition, self-sustaining flame propagation occurs.

Depending on the size of the dust particles and its electrical conductivity, dusty explosive mixtures are divided into 3 categories :

In addition, for the correct choice of electrical equipment in areas with the formation of explosive dust-air mixtures, the following should be taken into account:

for dusts capable of smoldering - smoldering temperature dust:

T t max. equipment – 50) ( 0 С) ( clause 7.3.63 of the EIC );

for dusts that are not capable of smoldering - autoignition temperature dust:

T r.v. ≥ 1.5×T max . equipment ( clause 7.3.63 of the EIC ).

3. An example of determining the category and group of explosive mixtures

For example, I will give the most familiar to most people explosive mixtures of gasoline and diesel fuel, which are sold at gas stations. According to Table. 7.3.3 PUE mixtures of vapors of these substances with air have the following categories and groups:

Diesel fuel (flash point less than 61 ºС): category II B, group T3.

Now the question is: which of the two indicated mixtures requires the use of electrical equipment with more high level protection? At first glance, the answer is obvious: gasoline (after all, it is much more explosive). But the above data, as it may seem strange, indicate the opposite: the category of the mixture of gasoline II A - the least dangerous of all industrial gases and vapors (BEMZ more than 0.9 mm), mixture group T2 - allows heating of the surface of electrical equipment up to 300 ° C; as for diesel fuel, the category of the mixture II B is more dangerous, and the T3 mixture group allows heating only up to 200 ° C. This is explained by the fact that gasoline has a much higher auto-ignition temperature than diesel fuel, and its calorific value (and, as a result, the explosion pressure) is lower.

It follows that explosion-proof electrical equipment that can be used in hazardous areas, formed by pairs diesel fuel, can also be used in areas where gasoline is circulated. On the contrary, electrical equipment for gasoline cannot be used in areas with diesel fuel, because. it can serve as a source of ignition of an explosive mixture even during normal operation.

Literature:

Cherkasov V.N., Kostarev N.P. Fire safety electrical installations: textbook. - M .: Academy of the State Fire Service of the Ministry of Emergency Situations of Russia, 2002. -377 p.

Federal Law No. 123-FZ dated August 22, 2008 " Technical regulation on fire safety requirements.

Rules for the installation of electrical installations. St. Petersburg: DEAN Publishing House, 2003. - 928 p.

GOST R 51330.19-99 (IEC 60079-20-96). Explosion-proof electrical equipment. Part 20: Data on combustible gases and vapors relevant to the operation of electrical equipment.

GOST R IEC 60079-0-2007. Explosive atmospheres. Part 0. Equipment. General requirements.

Korolchenko A.Ya., Korolchenko D.A. Fire and explosion hazard of substances and materials and means of extinguishing them. Directory: in 2 hours - 2nd ed., Revised. and additional – M.: Ass. Pozhnauka, 2004.

GOST 12.1.044-89. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination.

GOST R IEC 61241-1-1-99. Electrical equipment used in areas hazardous to ignition of combustible dust. Part 1: Electrical equipment protected by enclosures and surface temperature limitation. Section 1. Technical requirements.

GOST R IEC 61241-1-2-99. Electrical equipment used in areas hazardous to ignition of combustible dust. Part 1: Electrical equipment protected by enclosures and surface temperature limitation. Section 2. Selection, installation and operation.

GOST R 51330.2-99. Explosion-proof electrical equipment. Part 1. Explosion protection of the "flameproof enclosure" type. Appendix 1. Appendix D. Method for determining the safe experimental maximum clearance.

GOST R 51330.11-99. Explosion-proof electrical equipment. Part 12. Classification of mixtures of gases and vapors with air according to safe experimental maximum clearances and minimum igniting currents.

Article sent by: inzhener

The choice of electrical equipment for a particular environment is associated with the need to take into account the conditions of its operation and the explosive properties of the environment.
Considering the complexity of creating means of explosion protection of electrical equipment in relation to each explosive substance, in most countries of the world a conditional classification of explosive mixtures into categories and groups has been adopted.
This allows us to solve the issues of unification and classification of various industries according to the degree of explosiveness, depending on the use of certain combustible substances. In turn, this makes it possible to maximally unify the designs of explosion-proof electrical equipment, test methods, make general principles marking, greatly simplify its manufacture, installation of electrical installations and their operation.
International regulations, as well as national (other than the United States) regulations, only classify explosive gas mixtures. In the USA, according to NEC, both gaseous and dusty explosive mixtures are classified, and their division only into groups is provided.
In most countries of the world, a conditional classification of mixtures into categories and groups has been adopted.
The division of explosive substances into categories is based on their ability, mixed with air, to spread combustion through a slot (gap) of a flat flange connection on a standard shell.
The division of explosive mixtures into groups is based on the auto-ignition temperature, which is determined by the method recommended by the IEC. Here it should be clarified that ignition temperature explosive mixture of gases or vapors of combustible or flammable liquids is called a certain standard method lowest temperature, to which the specified mixture must be uniformly heated in order for it to ignite without introducing an external source of ignition into it. Of course, the higher this temperature, the less likely there is an explosion hazard.
The determination of the category and group of explosive mixtures is carried out by national testing stations. If in technological process In explosive industries there are various mixtures of substances, then the classification is made according to the most dangerous combination of components.
The classification of explosive mixtures into categories in various regulatory documents is based on the boundary values ​​​​of the so-called critical gap (critical gap width) or the value of the safe experimental maximum gap (BEMZ) and the minimum ignition current (MTV).
Obviously, the critical gap width for different mixtures is not the same: for slow-burning mixtures it is larger, and for fast-burning ones, for example, hydrogen-air mixtures, it is smaller.
In a number normative documents(IEC publications, European standards) the following criteria for classifying VZOS into categories and groups are used: MESG - maximum experimental safe clearance (BEMZ analog) and MIC - MTV analog.
To classify most gases and vapors into categories, it is sufficient to use one of the criteria: BEMZ (MESG) or MTV (MIC), except for the cases specified in clause 5 of GOST 12.1.011-78.
In cases where the value of BEMS or the value of MTV is unknown for a given gas or vapor, it is allowed to preliminarily accept the category of this chemical compound belonging to the same homologous series, but with a lower molecular weight.
The classification of the VZOS by temperature classes (which is similar to the classifications by groups, for example, GOST 12.1.011-78; PUE) is carried out according to a similar criterion, namely, the autoignition temperature.
We present the definition of these criteria.
Critical clearance - the value in millimeters of the gap between the surfaces of the flanges with a width of 25 mm, at which the frequency of transmission of explosions is 50% of the total number of explosions with a shell volume of 2.5 liters.
Safe Experimental Maximum Clearance (BEMZ) - the maximum gap between the flanges of the shell, through which the explosion does not transfer from the shell to the environment at any concentration of the combustible mixture in the air.
It should be emphasized that the value of the critical gap or BEMZ (MESG) cannot serve as parameters for controlling the explosion protection of explosion-proof electrical equipment during its manufacture and testing.
Minimum ignition current (MTV) is the ratio between the minimum ignition current of the gas or vapor under test and the minimum ignition current of methane.

Compliance with EIA classifications according to national and international standards

Considering that the enterprises of the country operate explosion-proof electrical equipment manufactured according to the previously valid national standards of the importing countries, the tables also show the correspondence of the VZOS classifications according to national standards these countries and their compliance with GOST 12.1.011-78*.

Control questions

1. What criteria are used to form the EIA groups and categories?
2. Give a definition of BEMZ, MTV, “critical gap”.
3. How many categories of VZOS and values ​​of their parameters (BEMZ, MTV) are defined by GOST 12.1.011-78.
4. How many VZOS groups and values ​​of their parameters are defined by GOST 12.1.011-78.
5. How many categories of VZOS and values ​​of their parameters (critical clearance) are determined by PIVE, PIVRE.
6. Give the distribution of VZOS by groups according to PWES.
7. Give the distribution of VZOS by groups according to PIWRE.
8. Provide classification of VZOS by groups and temperature classes according to EN50014.
9. Give the classification of the EIA according to the IEC Publication.
10. Give the classification of VZOS according to NEC-500-2.
11. Bring the classifications of VZOS into groups according to GOST 12.1.011-78 and PIVE, PIVRE, IEC, NEC-500.
12. Bring the VZOS classifications into categories (temperature classes) according to GOST 12.1.011-78 and PIVE, PIVRE, IEC, EN50014.

GOST R 51330.0-99 plain language. Part 13

Classification of gases and vapors emitted during operation .

Vapors and gases emitted from the flameproof enclosure during operation explosion-proof equipment subdivided into explosive categories. Classification is made relative to maximum safe experimental clearance (hereinafter BEMZ), that is, a gap through which gases and vapors escape. BEMZ is determined using a special experimental shell (the width of the flange connection is 25 mm).

The definition of BEMZ is carried out using a shell that meets the standard GOST R 51330.2. If an experimental shell of a spherical shape (with a volume of 8 dm) was used, then such results are considered to be preliminary.

BEMZ values explosion-proof equipment

• IIA (subgroup "A") - BEMZ has a value of more than 0.9 mm;
• IIB (subgroup "B") - BEMZ has a value in the range of 0.5-0.9 mm;
• IIC (subgroup "C") - BEMZ has a value > 0.5 mm.

Gases and vapors when using intrinsically safe explosion-proof equipment are classified based on the ratio of values ​​​​and the minimum required current to ignite the vapors and gases released, and minimum required current to ignite methane(hereinafter MTV).

MTV values explosion-proof electrical equipment depending on the explosion category:

• IIA (subgroup "A") - MTV has a value exceeding 0.8 mm;
• IIB (subgroup "B") - MTV has a value in the range - 0.45 mm - 0.8 mm;
• IIC (subgroup "C") - MTV has a value> 0.45 mm.

In order to determine the category (subgroup) of the explosiveness of a gas or steam, it is enough to perform one of the parameters (BEMZ or MTV) in the following values:

• IIA (subgroup "A") - BEMZ has a value greater than 0.9 mm or MTV greater than 0.8;
• IIB (subgroup "B") - BEMZ has a value in the range of -0.5-0.9 mm or MTV has a value in the range of 0.45-0.8;
• IIC (subgroup "C") - BEMZ > 0.5 mm or MTV > 0.45.

Cases requiring the definition and ratio of MTV BEMZ explosion-proof equipment:

• if the MTV values ​​are in the range of -0.8-0.9, then the necessary condition is to determine the BEMZ;
• if the MTV values ​​are in the range of -0.45-0.5, then the necessary condition is to determine the BEMZ;
• if the BEMZ values ​​are in the range of -0.5-0.55, then the necessary condition is the determination of the MTV.

If the emitted gas explosion-proof equipment belongs to the homologous series (compounds of elements that have the same structure) of complex compounds of chemical elements, then you can pre-deduce the result.

This happens with the help of calculations made from other elements of the same series, but with lower molecular weights.

Note:

- Industrial methane is characterized by the presence in its composition of a mixture of methane containing hydrogen about 15% of the total volume; - Additional information on vapors and gases is contained in GOST R 51330.19.

- During underground work in mountainous areas, methane is assigned to the I group of explosion hazard. Its BEMZ value exceeds 1.0 m. Methane for underground mining is firedamp containing gaseous hydrocarbons C2 - C5 in an amount not exceeding 0.1 by volume. In this case, a test for the amount of hydrogen is made after drilling and should not exceed 0.002 of the volume of gases (combustible).

Letter values ​​for gases and vapors:

a- determined by BEMZ;

b- determined by MTV;

With- is determined both by BEMZ and by the ratio of MTV;

d- is determined according to the similarity in the structure of chemical elements.

Gases not present in the list below can be distributed by determining the values ​​of BEMZ and MTV. In this case, it is necessary to take into account the peculiarities of their characteristics.

List of gases II A explosion category:

Hydrocarbons "c":

Cyclohexane;

Hydrocarbons "a":

Propylene;

Cyclopentane;

Cyclopropane;

Hydrocarbons "d":

Cyclobutane;

Decalin;

Ethylcyclopentane;

Methylcyclohexane;

Methylcyclobutane;

Ethylcyclohexane;

Ethylcyclobutane;

Methylcyclopentane;

Cycloheptane.

Hydrocarbons "b":

propyl alcohol;

amyl alcohol;

Butyl alcohol;

Hexyl alcohol;

Acetic aldehyde;

Propylmethylketol;

Butyl methyl ketone;

Acetylacetone;

Cyclohexanone;

Methyl formate;

Ethyl formate;

Ethyacetate;

propyl acetate;

methyl methacrylate;

vicyl acetate;

Ethyl acetoacetate.

Heptyl alcohol;

nonyl alcohol;

Methylcyclohexane;

diacetone alcohol;

Octyl alcohol;

Cyclohexanol;

metaldehyde;

Amyl methyl ketone;

Amyl acetate;

Methyl alcohol;

Ethanol;

Methiacetate;

Butyl acetate;

Acetic acid.

Compounds containing halogens "a":

Methane chloride;

I drank chloride;

Butyl chloride;

Dichloroethane;

Benzyl chloride;

Dichlorobenzene;

dichloroethylene;

Benzene trifluoride.

Compounds containing halogen "b":

Ethyl chloride;

Compounds containing halogen "d":

Ethyl bromide;

Butyl bromide;

Dichloropropane;

Chlorobenzene;

Alyl chloride;

dichloromethane;

Acetyl chloride;

Chlorethyl alcohol.

Compounds containing sulfur "a":

Tetrahydrothiophene.

Compounds containing sulfur "c":

Ethyl mercaptan.

Acetonitrile;

Methylamine;

Trimethylamine;

Dimethylamine;

Diaminethane.

Butylamine;

Compounds containing nitrogen "d":

Nitromethane; - diethylamine; - nitroethane;

propylamine;

Triethylamine;

Cyclohexylamine;

Monoethanolamine;

Pyridyl;

Phenamine;

Toluidine;

2-Diethylamineethanol;

NN - Dimethylaniline.

List of gases II In the explosion category:

Hydrocarbons "a":

Isopropylbenzene.

Hydrocarbons "c":

Butadiene.

Hydrocarbons "b":

Allilen.

Compounds containing oxygen "c":

dimethyl ether;

diethyl ether;

dibutyl alcohol;

Exipropane;

Epoxyethane;

Compounds containing oxygen "b":

Trioxan.

Compounds containing oxygen "d":

Ethyl methyl ether;

Dioxolane;

Tetrahydrofurfuryl alcohol;

Compounds containing oxygen "a":

Carbon monoxide;

Propamal; - butanol;

Dioxane; - glycolate;

methyl acrylate;

Cretonaldehyde;

Tetrahydrofuran;

Ethyl acrylate.

Compounds containing nitrogen "a":

Nitroethane;

Hydrogen cyanide.

Compounds containing nitrogen "c":

Acrylonitrite.

Compounds containing nitrogen "b":

Isopropyl nitrate.

Blends "d":

coke oven gas.

Compounds containing halogen "a":

epichlorohydride;

Tetrafluoroethylene.

Compounds containing sulfur "a":

Ethyl mercaptan.

List of gases II C, explosion category "c":

Hydrogen;

carbon disulfide;

Information about other features explosion-proof equipment see the following articles from the series "GOST R 51330.0-99 in plain language".