Certificate Number
Marking
Zone 20, Ex ia IIIC T160°C Da –20°C
≤
Ta
≤
+50°C, IP5X
The following describes the meaning of each part in the marking:
z
Ex: specific marking for explosion protection.
z
ia/ib: type of protection. It indicates that the product adopts intrinsic safety ia/ib suitable for use in
zones 0, 1, and 2 (gases) and zones 20, 21, and 22 (dusts). For details about the zones, see
Hazardous Area Classification
.
z
I/II/III: equipment group. Group I indicates that the product is intended for use in mines susceptible to
firedamp. Group II indicates that the product is intended for use in places with an explosive gas
atmosphere other than mines susceptible to firedamp. Group III indicates that the product is intended
for use in places with an explosive dust atmosphere.
z
A/B/C/D/E/F/G: gas group. It defines the type of hazardous material in the surrounding atmosphere.
Groups A, B, C, and D are for gases, while groups E, F, and G are for dusts and flyings.
z
T3/T4: temperature class. T3 indicates that the maximum surface temperature during product use is
200°C. T4 indicates that the maximum surface temperature during product use is 135°C.
z
T120°C/T160°C: It indicates that the maximum surface temperature during product use is 120°C or
160°C.
Ga/Ma/Da/Db: equipment protection level. It is the level of protection that is given to equipment based on
the likelihood of its becoming a source of ignition and distinguishing the difference between explosive
gas atmospheres, explosive dust atmospheres, and the explosive atmospheres in mines susceptible to
firedamp.
z
IP5X: ingress protection code. It indicates the degree of protection against solids and liquids.
1.2
Explosives Classification
z
I: firedamp
z
II: explosive mixture (vapors and mists)
z
III: explosive dusts (fibers or flyings)
1.3
Hazardous Area Classification
Hazardous area is a potentially flammable or explosive area with flammable or explosive gases, vapors,
or liquids or flammable dusts or fibers. Hazardous areas are classified into the following types:
Hazardous
Substance
Present for Long
Periods (1000 hours
above per year)
Present in Normal
Operation (10–1000 hours
per year)
Present in Abnormal
Operation (10 hours below
per year)
