Locations where flammable atmospheres are likely to occur include:
- Paint spraying equipment areas
- Large chemical process plants/Oil refineries
- Petrol station forecourts
- Petroleum/gas pumping stations
- Fuel storage depots
- Fuel distribution points
- Flour, coal, sugar milling areas
- Water treatment plant
The likelihood of a flammable atmosphere being present is classified as follows:
- Zone 0 - continuous hazard
- Zone 1 - intermittent hazard
- Zone 2 - hazard under abnormal conditions
The specification for electrical equipment varies for each zone and, sometimes, with the flammable substance type.
The safe use of electrical equipment in potentially flammable atmospheres requires specialist knowledge, equipment and operating systems (including a permit-to-work where appropriate). It is necessary to have any work in this area completed by a competent person. This includes specification of the electrical equipment, installation and usage/testing procedures.
The NICEIC and ECA publish a list of contractors for hazardous work on their websites.