Introduction to explosion proof signs

Generally in combustible gas environment, explosion-proof products must be used when using electrical products. The shell of explosion-proof products generally has the following marks, with the specific meanings as follows:
Ex d Ⅱ B T4
① ② ③ ④ ⑤
① Explosion proof signs of China and International Electrotechnical Commission
② , flameproof type
③ Electrical equipment other than coal mine and underground
④ According to the maximum experimental safety gap or the minimum ignition current in explosive gas environment, it can be divided into three levels: ABC
⑤ According to the maximum surface temperature of the equipment, it is divided into six groups: T1 to T6
Bit 1 Code:
Ex — explosion proof mark of China and International Electrotechnical Commission; Eex — European Community; ad — Italy; MS, AE — France; FLP — UK; UL, FM — us; E — Germany \ IEC
Bit 2 code
Code / explosion-proof type / national standard / explosion-proof measures / applicable area
D flameproof gb3836.2 isolated ignition sources Zone1 and zone2
E increase safety gb3836.3 try to prevent ignition source Zone1, zone2
Energy zone 0-2 of IA intrinsically safe gb3836.4 limited ignition source
IB intrinsically safe gb3836.4 limits the energy of ignition sources Zone1 and zone2
P positive pressure gb3836.5 separation of hazardous substances from ignition sources Zone1, zone2
O oil filled gb3836.6 hazardous substances separated from ignition sources Zone1, zone2
Q sand filled gb3836.7 separation of hazardous substances from ignition sources Zone1, zone2
N non sparking gb3836.8 try to prevent ignition source zone2
M pouring and sealing gb3836.9 try to prevent the ignition source Zone1, zone2
H air tight gb3836.10 try to prevent ignition source Zone1, zone2
S special type
Dip dust explosion-proof type is used in explosive dust environment, and there is no need to add ex or Eex signs in front of it
③ bit code
I – electrical equipment for coal mine and underground
Ⅱ – Factory electrical equipment
④ bit code
Classification of class II explosive gas environment
Working condition class representative gas minimum ignition spark energy maximum experimental safety clearance MESG (mm) minimum ignition current ratio micr
Methane under mine I 0.280mj
Plant Ⅱ a propane 0.180mj MESG ≥ 0.9 MICR > 0.8
IIb ethylene 0.060mj 0.9 > MESG > 0.50.8 ≥ MICR ≥ 0.45
Ⅱ C hydrogen 0.019mj 0.5 ≥ MESG 0.45 > micr
Bit ⑤ code
Temperature group of electrical equipment in class II explosive gas environment
Temperature group natural temperature T (℃) allowable surface temperature of common explosive gas equipment (℃)
T1 t ≥ 450 46 kinds of 450, such as hydrogen, acrylonitrile, etc
T2 450 > t ≥ 300 47 kinds of acetylene, ethylene, etc. 300
T3 300 > t ≥ 200 gasoline, butenal, etc. 36 kinds 200
T4 200 ＞ t ≥ 135, 6 kinds of acetaldehyde, tetrafluoroethylene, etc.135
T5 135 ＞ t ≥ 100 carbon disulfide 100
T6100 > t ≥ 85 ethyl nitrate and 85 ethyl nitrite
Hazard classification of dangerous places:
Regional definition of explosive substances: Chinese standard / North American Standard
1. Under normal conditions, the explosive gas mixture exists continuously or for a long time in Zone 0 Div.1.
2. Area 1 where explosive gas mixtures are likely to occur under normal conditions.
3. Under normal conditions, explosive gas mixture is impossible to appear, only under abnormal conditions, occasionally or for a short time, in zone 2 div.2.
4. Under normal conditions, the mixture of explosive dust or combustible fiber and air may be continuous, and Div.1 in zone 10 occurs frequently in a short time or for a long time.
5. Under normal conditions, explosive dust or mixture of combustible fiber and air can not appear, only under abnormal conditions, occasionally or for a short time, in area 11 div.2.