Under the ATEX directive (94/9/EC), any product intended for use in potentially explosive atmospheres must bear the ATEX "CE" mark and be affixed under the auspices of an EC Notified Body.

The Notified Body must not only test the product for compliance with the Harmonised Standards (EC Type Examination) but must also undertake Production Quality Assurance and Product Verification.

Within the ATEX directive, equipment is classified into five categories according to the level of risk in its intended area of use.

Equipment intended for use in Zone 0 would normally be classified under ATEX as Category 1. This would include equipment designed to meet the Intrinsic Safety ‘ia’ standard.

Equipment intended for use in Zone 1 would normally be classified as ATEX Category 2.

Equipment complying with the following protection standards are included in Category 2.

• Intrinsic safety ‘ib’
• Flameproof enclosure ‘d’
• Increased safety ‘e’
• Purged and pressurised ‘p’
• Encapsulated ‘m’
• Oil filled ‘o’
• Powder filled ‘q

Equipment intended for use in Zone 2 would normally be classified as ATEX Category 3. This would include equipment designed to the non-incendive 'n' standard.