A fan for a Zone 2 hazardous area must be designed, manufactured and certified as ATEX Category 3G equipment, with a motor protected to match. For a direct replacement of an existing fan at a palm oil mill anaerobic digestion plant in Indonesia, the quotation was for a 304 stainless steel fan with a 30 kW Ex ec motor, delivered in 15 to 16 working weeks.
The challenge: a fan that must not become an ignition source
Biogas can form an explosive atmosphere around equipment. Areas where this is unlikely in normal operation but possible occasionally are classified as Zone 2. Electrical and mechanical equipment in a Zone 2 area must be certified for it.
The approach: specify the certification, not only the fan
- Fan: model 385TSGXZ in 304 stainless steel.
- Motor: 30 kW, Ex ec (increased safety), IP56, tropicalised.
- Certification: designed, manufactured and certified to ATEX Zone 2, Category 3G.
- Interface: a direct replacement for a fan of a stated serial number, so connections match.
- Delivery: 15 to 16 working weeks to the port, with packing and sea freight.
Why it works
Category 3G equipment is intended for Zone 2 gas atmospheres. Stainless steel avoids the need for a protective paint system. A direct replacement avoids changes to ducting. In the UK, the HSE explains hazardous area duties under DSEAR and equipment requirements under ATEX.
What to consider for your own project
- Get the area classification first. It sets the certification category.
- Ask for the certificate with the fan, not only the datasheet.
- Match the motor protection to the zone.
- Plan for lead time, nearly four months.
- Check the material against the gas and the atmosphere.
For a non-hazardous exhaust application, see our post on replacing a hot exhaust gas fan.
FAQ
What does Category 3G mean?
Equipment for gas atmospheres where an explosive mixture is unlikely and brief.
What does Ex ec mean?
A protection type, increased safety, for motors in Zone 2.
Why stainless steel?
For resistance to a corrosive, humid gas.