1. What is Zone 2 hazardous area?
Zone 2 is an area where an explosive mixture of flammable gas, vapour or mist is unlikely to occur under normal operating conditions, and if it appears, it will only exist for a short time due to accidental leakage, equipment fault or poor ventilation. It is a lower-risk gas hazardous zone compared with Zone 1.
2. What ATEX marking is required for Zone 2 gensets?
Standard marking: Ex II 3G Gc
II: Equipment for surface industrial sites (not underground mining)
3G: Equipment Category 3, applicable to gas Zone 2
Gc: Equipment Protection Level for Zone 2
Common protection types for Zone 2 units: Ex nA, Ex ec, Ex p. Flameproof Ex d is also acceptable but over-grade.
3. What gas group should I choose (IIA / IIB / IIC)?
IIA: Natural gas, methane, propane, butane, petrol vapour; IIA/IIB/IIC gensets all fit
IIB: Ethylene, town gas, most solvent vapours; only IIB or IIC gensets can be used
IIC: Hydrogen, acetylene; only IIC certified Zone 2 gensets are allowed
Rule: The genset gas group must be equal to or higher than your site gas.
4. What does temperature class T3 / T4 mean?
T-class limits the maximum surface temperature of the unit to avoid igniting surrounding flammable gas:
T3: Max surface temp ≤200°C, widely used for natural gas & propane sites
T4: Max surface temp ≤135°C, mandatory for ethylene, hydrogen and petrochemical vapours
T5/T6: For special solvents with very low auto-ignition temperature
5. Can a Zone 2 generator be used in Zone 1?
No. Zone 2 equipment (3G / Gc) only meets low-risk environment standards. Zone 1 requires Category 2G / Db or Dc higher explosion protection level, which our Zone 2 unit cannot satisfy.
6. What explosion-proof components are equipped on Zone 2 diesel gensets?
Non-sparking alternator Ex nA / Ex ec
Explosion-proof control panel, sensors, wiring glands
Spark arrester / flame trap on exhaust pipe
Sealed, non-sparking starter motor
Anti-static fuel & cooling pipelines
Fully sealed electrical junction boxes to prevent gas ingress