This standard specifies the basis for classification of flammable gases and vapors produced, stored and used in a large number of industries, and provides guidance on classification tests for gases or vapors not included in Appendix A (reference). This standard applies to explosion-proof electrical equipment and intrinsically safe electrical equipment. The corresponding category and level of the equipment should be selected based on the types of gases and vapors contained in the environment in which it is used. GB 3836.12-1991 Explosion-proof electrical equipment for explosive environments. Classification of gas or vapor mixtures according to their maximum test safety clearance and minimum ignition current. GB3836.12-1991 Standard download and decompression password: www.bzxz.net

National Standard of the People's Republic of China
Explosion-proof electrical equipment for explosive atmospheres
Classification of gases or vapor mixtures according to their maximum test safety gap and minimum ignition current Electrical apparatus for explosive atmospheresClassificatlon of gases or vapors with airaccording to their maximum experimentalsafe gaps and minimun igniting currentsGB3836.12-91
IEC79-12-1978
This standard is equivalent to the international standard IEC79-12 (1978) "Explosion-proof electrical equipment for explosive gas environments Gas or vapor mixtures" Classified according to its maximum test safety gap and minimum ignition current. 1 Subject content and scope of application
This standard specifies the classification basis for flammable gases and vapors (hereinafter referred to as gases and vapors) produced, stored and used in a large number of industries, and provides information not listed in Appendix A (reference) Guidelines for classification testing of incoming gases or vapors. This standard applies to explosion-proof electrical equipment and intrinsically safe electrical equipment. The corresponding category and level of the equipment should be selected based on the types of gases and vapors contained in the environment in which it is used. 2 Reference standards
GB3836.11 Determination method of maximum test safety gap for explosion-proof electrical equipment for explosive environments 3 Terminology
3.1 Explosive gas mixtures
Under atmospheric conditions, gases, vapors, mist A flammable substance mixed with air that, when ignited, will cause combustion to spread throughout the entire range of the mixture.
3.2 The most easily ignitable mixture (electric spark) requires the minimum electrical energy to ignite the mixture under specified conditions. 3.3 Maximum test safety gap (MESG)
Under the test conditions specified in the standard, after all concentrations of the tested gas or mixture of steam and air in the shell are ignited, no explosive gas outside the shell can be ignited through the 25mm long joint surface The maximum gap between two parts of the shell cavity of a mixture. 3.4 Minimum ignition current (MIC)
The minimum current that can ignite the most ignitable mixture under the specified test conditions. 4 Classification of gases and vapors
According to the requirements for electrical equipment to be suitable for a certain gas or vapor environment, the gas or vapor is classified and classified, so that explosion-proof electrical equipment or intrinsically safe electrical equipment is classified into this category and grade manufacturing to ensure the corresponding explosion-proof safety performance of the equipment. The general principles for gas and vapor classification in Appendix A (reference) are as follows. The State Bureau of Technical Supervision approved the implementation on 1992-02-01 on 1991-05-27
GB3836.12-91
4.1 connected to the maximum test safety gap (MESG) or minimum ignition current ratio (MICR) classification for Flameproof electrical equipment, gases and vapors are classified according to the Maximum Test Safety Gap (MESG). The maximum test safety gap (MESG) is measured according to GB3836.11. The maximum test safety gap (MESG) of individual gases or vapors is measured using an 8L spherical standard enclosure and is temporarily approved.
For intrinsically safe electrical equipment, gases and vapors are classified according to the ratio of the minimum ignition current to the minimum ignition current for laboratory methane (MICR). The minimum ignition current (MIC) is measured according to the test device specified in IEC Publication 79-3 (1972, second edition) "Spark Test Device for Intrinsically Safe Circuits of Electrical Equipment for Explosive Gas Atmospheres". The minimum ignition current (MIC) of individual gases or vapors is measured using other test devices and is temporarily approved. The classification of classes and classes of gases and vapors is consistent with the classification of classes and classes of explosion-proof and intrinsically safe electrical equipment. Flameproof and intrinsically safe electrical equipment are divided into three categories. Category I: Electrical equipment for underground coal mines (methane); Category I: Electrical equipment for factories.
Class I electrical equipment is divided into three levels: A, B, and C according to its maximum test safety gap (MESG) and minimum ignition current ratio (MICR) applicable to explosive gas mixtures, as shown in Table 1. Table 1
Class, level
IA
IIB
TIC
MESG
mm
MESG≥0.9|| tt||0.9>MESG>0.5
MESG≤0.5
Note, the maximum test safety gap (MESG) is measured at 20℃ or corrected to 20℃. The classification principle of gases and vapors is
MICR
MICR>0.8
0.8≥MICR≥0.45
MICR<0.45
4.1.1 in accordance with Table 2 When conditions are met, classification only needs to be based on the measured maximum test safety gap (MESG) or minimum ignition current ratio (MICR). Most gases and vapors can be classified on this basis. Table 2
Class, level
IIA
B
c
MESG
mm
MESG>0.9|| tt||0.9≥MESG≥0.55
MESG<0.5
MICR
MICR>0.9
0.8≥MICR≥0.5
MICR<0.45|| tt||4.1.2 When the following conditions occur, the maximum test safety gap (MESG) and minimum ignition current ratio (MICR) must be measured simultaneously before classification can be carried out.
a.
The measured MICR value is: 0.9≥MICR>0.8; the measured MICR value is: 0.5>MICR≥0.45; b.
c.||tt ||The measured MESG value is: 0.55mm>MESG≥0.5mm. 4.2 Classification based on similarity in chemical structure
When a gas or vapor belongs to one of the homologous compounds, the inference method can be used to temporarily classify it into the same level as other compounds with smaller molecular weights in the homologous compounds.
4.3 Classification of multi-component gas mixtures
For multi-component gas mixtures, the maximum test safety gap (MESG) or minimum ignition current ratio (MICR) must be specifically measured to determine its grade.
A1 Description
GB3836.12-91
Appendix A
Gas and Vapor Classification Table
(reference)
Attachment Some flammable substances in it are relatively unstable and easy to decompose on their own. For example: ethyl nitrate. A1.1
A1.2 The list of gases and vapor types is incomplete. A1.3 The classification results of listed compounds also apply to all isomers of the compound. The meanings of the letters in the "Grading Method" column in the A1.4 table are as follows: a
- graded by MESG;
b - graded by MICR;
c||tt || One is classified according to MESG and MICR;
One compound has a homologous chemical structure and is classified according to the inference method. d
Table A1 Class IA gas or vapor
Gas, vapor name
1 Hydrocarbons
1.1 Alkanes
Methane
B alkane
propane
butane
pentane
hexane
heptane
octane
wangane| |tt||Tranane
cyclobutane
cyclopentane
cyclohexane
cycloheptane
CH.||tt| |C2Hg
CsH.
CHio
CoH12
CgHu
CHie
C.Hia
CoH2e||tt ||CoH22
CH2(CH2)2CH2
CH2(CH2)CH2
CH2(CH2),CH2
Molecular formula
CH2(CH,) ,CH2
Classification method
c
c
c
c
c
c
a
d
a
d
Name of gas and vapor
Methylcyclobutane
Methylcyclopentane
Methylcyclohexane
Ethylcyclobutane
Ethylcyclopentane
Hexylcyclohexane
Decalin
1.2 Alkenes
Propene
1.3 Aromatic hydrocarbons
Styrene
Isopropenylbenzene
(Methylstyrene)
1.4 Benzene
Benzene
Toluene
Xylene
Ethylbenzene
Trimethylbenzene
Naphthene
Isopropylbenzene
Methylisopropylbenzene
1.5 Mixed hydrocarbons
Methane (industrial)2)
Turpentine
Naphtha
Coal tarNaphtha
GB3836.12—91
Continued Table A1
Molecular formula
CH,CH(CH2)2CH2
CH:CH(CH2):CH2
CHCH(CH2),CH2
C2H,CH(CH2)CH2|| tt||C2H,CH(CH2)CHz
C2H;CH(CH2),CH2
CH2(CH2),CHCH(CH,),CH2
C2H,=CH2
CHCH-CH2
CHC(CHs)=CH2
CoHs
CHsCHs
CH(CH)
CHC,H,
C.Ha(CHa)
CroH
CHCH(CHa)
(CH,),CHC.H,CHs
Classification method
d
d
d||tt| |d
d
9
b
a
c
d
a
d
d
d
d
a(predicted)
d
d
Name of gas and vapor
Petroleum (including motor gasoline)
Solvent petroleum or washed petroleum
Fuel oil
Kerosene
Diesel
Power benzene
2Oxygenated compounds
2.1Oxides (including ethers)
Carbon monoxide\
(Di)propionaldehyde
2.2Alcohols and phenols|| tt||Methanol
Ethanol
Propanol
Butanol
Pentanol
Hexanol
Heptanol
Octanol
Octanol
Cyclohexanol
Methylcyclohexanol
Phenol
Cresol
4-Hydroxy-4-methylpentyl (dipropylene glycol)
2.3 Aldehydes
Acetaldehyde
Polyacetaldehyde
2.4 Ketones
Acetone
GB3836.12—91
Continued Table A1
Molecular formula
co
(C,H,),0
CH.OH
C,HgO H
CH,OH
CH.OH
CsHuOH
CHOH
CHiOH
C.HuOH
CgHigOH
CH2(CH2),CHOH
CH,CH(CH,),CHOH
CHOH
CH.CH,OH
(CH)C(OH)CH,COCH
CH.CHO
(CHCHO).
(CH)2CO
Grading method
d
d
d
d||tt| |a
c
a
c
c
a
a
a
d
d
d
d
d
d
d
a
d
c
Butanone-2
Name of gas and vapor
(Ethyl methyl ketone)
Pentanone-2
(Methyl propyl ketone)
Hexanone-2
(Methyl butyl ketone)
Amyl methyl ketone
Amyl dione
(Acetylacetone)
Cyclohexanone| |tt||2.5 Esters
Methyl formate
Ethyl formate
Methyl acetate
Ethyl acetate
Propyl acetate
Butyl acetate
Amyl acetate
Methyl methacrylate
Ethyl methacrylate
Vinyl acetate
Ethyl acetyl ester
2.6 Acids
Acetic acid
3 Halogen-containing compounds
3.1 Oxygen-free compounds
Methyl fluoride
Ethyl chloride
Ethyl bromide
Propyl chloride
Fluorobutane
Butyl bromide
Difluoroethane
Dichloropropane
GB 3836.12-91
Continued Table A1
Molecular formula
C,HCOCHs
C:H,CoCH3
C,H.COCH
CHnCoCHs
CHCOCH2COCHs
CH2(CH2),CO
HCOOCH
HCooC.Hs
CH.COOCHs
CH.COOC.Hs
CH.COOC.H
CH,CooC,H
CHCOOCsHn
CH2- C(CH,)COOCH,
CH2-C(CH,)COOC,H,
CH,COOCH=CH2
CH.COCH2COOC,H.
CH.COOH
CH.CI
C2HgC1
C.HsBr
CHiCl
CH.C1
CHBr
C2H.C12
CHCl2
Classification method
c
a
a
d
a
a||t t||a
a
a
a
c
d
a
d
a
a
b
a
b
d
a
a
d
Chlorobenzene
Allyl chloride
Dichlorobenzene
Name of gas and vapor
Allyl chloride
Dichloroethylene
Vinyl chloride
Trifluorotoluene
Difluoromethane
3.2
Contains Oxygen compounds
Acetyl chloride
Chloroethanol
4 Sulfur compounds
Ethyl mercaptan
Propanethiol
Thiophene
Tetrahydrothiophene
5 Nitrogen compounds
Ammonia
Acetonitrile
Ethyl nitrite
Nitromethane
Nitroethane
5.1 Amines
Methylamine
Trimethylamine
Trimethylamine
Triethylamine
Triethylamine
n-Propylamine
n-Butylamine
Cyclohexylamine
2-Ethanolamine
GB3836.12-91
Continued Table A1
Molecular formula
CHC1
C.HsCH2CI
CHCl2
CH2=CHCH2C1
CHCI=CHC1
CH2CHCI
CoH.CFs
CH,Cl2
CH:CoCI
CH,CICH2OH
C.HsSH| |tt||CH-SH
CHCHCH=CHS
CH2(CH2)2CH,S
NHs
CH.CN
CH.CH, ONO
CH.NO2
C2HsNO2
CH.NH2
(CH3)2NH
(CHs)sN
(C2Hs)2NH
(C2Hs)sN
CH,NH2
CHNH2
CH2(CH2),CHNHz
NH2CH2CH20H
Grading method||tt ||d
d
d
b
a
c
a
d
a
a
e
a(predicted)
a
a
a
a||tt ||d
d
a
a
a
d
d
d
c
d
d
1
Gas, vapor name
2-diethylaminoethanol
diazoethane
Aniline
NN-dimethylaniline
anilinopropane
toluidine
pyridine (azo(hetero)benzene)
GB3836.12—91
Continued Table A1
Molecular formula
(C,H),NCH2CH20H
NH,CH.CH2NH2
CoHsNH||tt ||CHN(CHs)2
CH.CH.CH(NH2)CHs
CH.CHNH2
CsHsN
Note: 1) means the impurity content can be ignored Methane is not counted. 2) Methane (industrial) is a methane mixture containing less than 15% (volume ratio) hydrogen. 3) Carbon monoxide can contain moisture that saturates its mixture with air under abnormal ambient temperatures. Class 2IB gas or vapor
Table A2
Gas and vapor names
Hydrocarbons
Propylene
Ethylene
Cyclopropane|| tt||1,3-butadiene
nitrogen-containing compounds
2
acrylonitrile
isopropyl nitrate
hydrogen cyanide| |tt||3 oxygenates
triformaldehyde
ethyl methyl ether
diethyl ether
tributyl ether
ethylene oxide| |tt||1,2-propylene oxide
1,3-dihydropentane
CH.C=CH
C2H.
CH2CH2CH2||tt ||Molecular formula
CH2=CHCH=CH2
CH2=CHCN
(CH:)2CHONO2
HCN
(CHs)20||tt| |CH.OC.Hs
(C2Hs)20
(CHe)20
CH,CH,0
CH:CHCH20
CH,CH20CH20
grading method
d
a
d
d
d
d
d| |tt||Grading method
b
e
b
c
b
a
c|| tt||d
c
.c
c
c
d
Gas, vapor name
1 ,4-dioxan
1,3,5-triane
butyl hydroxyacetate
tetrahydrol
methyl acrylate
acrylic acid Ethyl ester
furan
butenal
acrolein
tetrahydrofuran
4 mixture
coke oven gas|| tt||5 halogen-containing compounds
tetrafluoroethylene
chloromethoxypropane,
2-chloro-1,2-epoxypropane
gas, vapor Name
Hydrogen
Acetylene
Carbon disulfide
Ethyl nitrate
Additional instructions:
GB 3836.12—91
Continued Table A2
Molecular formula
CH,CH,OCH,CH20
CH20CH20CH20
HOCH2COOC.H
CH.CH.CH2OCHCH2OH
CH ,-CHCOOCHs
CH2-CHCOOC,H,
CH=CHCH=CHO
CH,CH=CHCHO
CH2-CHCHO
CH2(CH2 )2CH20
C2F.
OCH,CHCH,C1
Table A3
IC grade gas or vapor
Molecular formula
H2|| tt||CH2
CS2
C.HsONO2
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Explosion-Proof Electrical Equipment. This standard is drafted by the Nanyang Explosion-proof Electrical Research Institute of the Ministry of Mechanical and Electronic Industry. The main drafters of this standard are Ji Minghuan and Xiang Yunlin. Grading method
a
b
d
a
a
a
a
a (Predicted)
a
d
grading method
c
c
c
CHNHz
NH2CH2CH20H
Grading method
d
d
d
b
a
c
a
d
a
a
e
a(predicted)
a||tt| |a
a
a
d
d
a
a
a
d
d
d
c
d
d
1
Gas, vapor name
2-diethylaminoethanol
diazoethane
aniline
NN-dimethylaniline
anilinopropane
toluidine| | tt | tt||NH,CH.CH2NH2
CoHsNH
CHN(CHs)2
CH.CH.CH(NH2)CHs
CH.CHNH2||tt| |CsHsN
Note: 1) Refers to methane with negligible impurity content. 2) Methane (industrial) is a methane mixture containing less than 15% (volume ratio) hydrogen. 3) Carbon monoxide can contain moisture that saturates its mixture with air under abnormal ambient temperatures. Class 2IB gas or vapor
Table A2
Gas and vapor names
Hydrocarbonsbzxz.net
Propylene
Ethylene
Cyclopropane|| tt||1,3-butadiene
nitrogen-containing compounds
2
acrylonitrile
isopropyl nitrate
hydrogen cyanide| |tt||3 oxygenates
triformaldehyde
ethyl methyl ether
diethyl ether
tributyl ether
ethylene oxide| |tt||1,2-propylene oxide
1,3-dihydropentane
CH.C=CH
C2H.
CH2CH2CH2||tt ||Molecular formula
CH2=CHCH=CH2
CH2=CHCN
(CH:)2CHONO2
HCN
(CHs)20||tt| |CH.OC.Hs
(C2Hs)20
(CHe)20
CH,CH,0
CH:CHCH20
CH,CH20CH20
grading method
d
a
d
d
d
d
d| |tt||Grading method
b
e
b
c
b
a
c|| tt||d
c
.c
c
c
d
Gas, vapor name
1 ,4-dioxan
1,3,5-triane
butyl hydroxyacetate
tetrahydrol
methyl acrylate
acrylic acid Ethyl ester
furan
butenal
acrolein
tetrahydrofuran
4 mixture
coke oven gas|| tt||5 halogen-containing compounds
tetrafluoroethylene
chloromethoxypropane,
2-chloro-1,2-epoxypropane
gas, vapor Name
Hydrogen
Acetylene
Carbon disulfide
Ethyl nitrate
Additional instructions:
GB 3836.12—91
Continued Table A2
Molecular formula
CH,CH,OCH,CH20
CH20CH20CH20
HOCH2COOC.H
CH.CH.CH2OCHCH2OH
CH ,-CHCOOCHs
CH2-CHCOOC,H,
CH=CHCH=CHO
CH,CH=CHCHO
CH2-CHCHO
CH2(CH2 )2CH20
C2F.
OCH,CHCH,C1
Table A3
IC grade gas or vapor
Molecular formula
H2|| tt||CH2
CS2
C.HsONO2
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Explosion-Proof Electrical Equipment. This standard is drafted by the Nanyang Explosion-proof Electrical Research Institute of the Ministry of Mechanical and Electronic Industry. The main drafters of this standard are Ji Minghuan and Xiang Yunlin. Grading method
a
b
d
a
a
a
a
a (predicted)
a
d
grading method
c
c
c
CHNHz
NH2CH2CH20H
Grading method
d
d
d
b
a
c
a
d
a
a
e
a(predicted)
a||tt| |a
a
a
d
d
a
a
a
d
d
d
c
d
d
1
Gas, vapor name
2-diethylaminoethanol
diazoethane
aniline
NN-dimethylaniline
anilinopropane
toluidine| | tt | tt||NH,CH.CH2NH2
CoHsNH
CHN(CHs)2
CH.CH.CH(NH2)CHs
CH.CHNH2||tt| |CsHsN
Note: 1) Refers to methane with negligible impurity content. 2) Methane (industrial) is a methane mixture containing less than 15% (volume ratio) hydrogen. 3) Carbon monoxide can contain moisture that saturates its mixture with air under abnormal ambient temperatures. Class 2IB gas or vapor
Table A2
Gas and vapor names
Hydrocarbons
Propylene
Ethylene
Cyclopropane|| tt||1,3-butadiene
nitrogen-containing compounds
2
acrylonitrile
isopropyl nitrate
hydrogen cyanide| |tt||3 oxygenates
triformaldehyde
ethyl methyl ether
diethyl ether
tributyl ether
ethylene oxide| |tt||1,2-propylene oxide
1,3-dihydropentane
CH.C=CH
C2H.
CH2CH2CH2||tt ||Molecular formula
CH2=CHCH=CH2
CH2=CHCN
(CH:)2CHONO2
HCN
(CHs)20||tt| |CH.OC.Hs
(C2Hs)20
(CHe)20
CH,CH,0
CH:CHCH20
CH,CH20CH20
grading method
d
a
d
d
d
d
d| |tt||Grading method
b
e
b
c
b
a
c|| tt||d
c
.c
c
c
d
Gas, vapor name
1 ,4-dioxan
1,3,5-triane
butyl hydroxyacetate
tetrahydrol
methyl acrylate
acrylic acid Ethyl ester
furan
butenal
acrolein
tetrahydrofuran
4 mixture
coke oven gas|| tt||5 halogen-containing compounds
tetrafluoroethylene
chloromethoxypropane,
2-chloro-1,2-epoxypropane
gas, vapor Name
Hydrogen
Acetylene
Carbon disulfide
Ethyl nitrate
Additional instructions:
GB 3836.12—91
Continued Table A2
Molecular formula
CH,CH,OCH,CH20
CH20CH20CH20
HOCH2COOC.H
CH.CH.CH2OCHCH2OH
CH ,-CHCOOCHs
CH2-CHCOOC,H,
CH=CHCH=CHO
CH,CH=CHCHO
CH2-CHCHO
CH2(CH2 )2CH20
C2F.
OCH,CHCH,C1
Table A3
IC grade gas or vapor
Molecular formula
H2|| tt||CH2
CS2
C.HsONO2
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Explosion-Proof Electrical Equipment. This standard is drafted by the Nanyang Explosion-proof Electrical Research Institute of the Ministry of Mechanical and Electronic Industry. The main drafters of this standard are Ji Minghuan and Xiang Yunlin. Grading method
a
b
d
a
a
a
a
a (Predicted)
a
d
grading method
c
c
c
2-Propylene oxide
Gas, vapor name
Hydrogen
Acetylene
Carbon disulfide
Ethyl nitrate
Additional notes: || tt||GB 3836.12—91
Continued Table A2
Molecular formula
CH,CH,OCH,CH20
CH20CH20CH20
HOCH2COOC.H||tt ||CH.CH.CH2OCHCH2OH
CH,-CHCOOCHs
CH2-CHCOOC,H,
CH=CHCH=CHO
CH,CH=CHCHO||tt ||CH2-CHCHO
CH2(CH2)2CH20
C2F.
OCH,CHCH,C1
Table A3
IC grade gas or vapor| |tt||Molecular formula
H2
CH2
CS2
C.HsONO2
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Explosion-Proof Electrical Equipment. This standard is drafted by the Nanyang Explosion-proof Electrical Research Institute of the Ministry of Mechanical and Electronic Industry. The main drafters of this standard are Ji Minghuan and Xiang Yunlin. Grading method
a
b
d
a
a
a
a
a (Predicted)
a
d
grading method
c
c
c
2-Propylene oxide
Gas, vapor name
Hydrogen
Acetylene
Carbon disulfide
Ethyl nitrate
Additional notes: || tt||GB 3836.12—91
Continued Table A2
Molecular formula
CH,CH,OCH,CH20
CH20CH20CH20
HOCH2COOC.H||tt ||CH.CH.CH2OCHCH2OH
CH,-CHCOOCHs
CH2-CHCOOC,H,
CH=CHCH=CHO
CH,CH=CHCHO||tt ||CH2-CHCHO
CH2(CH2)2CH20
C2F.
OCH,CHCH,C1
Table A3
IC grade gas or vapor| |tt||Molecular formula
H2
CH2
CS2
C.HsONO2
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Explosion-Proof Electrical Equipment. This standard is drafted by the Nanyang Explosion-proof Electrical Research Institute of the Ministry of Mechanical and Electronic Industry. The main drafters of this standard are Ji Minghuan and Xiang Yunlin. Grading method
a
b
d
a
a
a
a
a (predicted)
a
d
grading method
c
c
c
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