What are IECEx/ATEX Explosion Protection (Ex) Safety Standards?

Time:Oct 29,2025

IECEx and ATEX are safety standard requirements for the construction, testing, and marking of electrical equipment, components, or devices used in explosive atmospheres. Both IECEx and ATEX meet the same standard (e.g., IEC-EN 60079), and technically, they are essentially identical. IECEx is an international certification system for equipment used in explosive atmospheres. Its quality assessment specifications are based on standards developed by the International Electrotechnical Commission (IEC). The purpose of IECEx standards is to maintain the necessary safety levels in the international trade of equipment and services used in explosive atmospheres. The ATEX Directive, on the other hand, is for the certification protection of equipment used in potentially explosive atmospheres. The directive stipulates that core health and safety requirements and compliance assessment procedures must be met before such products are placed on the EU market.

1. What factors can trigger an explosion?

An explosion requires three components: a combustible quantity of flammable material, such as combustible dust/particulate matter or gas/mist; oxygen; and an ignition source such as a spark, electrostatic discharge, or open flame.

2. In which fields are explosion-proof equipment typically used? Any industry/operation that manufactures, handles, or uses flammable materials. Examples include: gas stations, oil refineries, drilling platforms and processing plants, chemical processing plants, the printing industry (paper and textiles), aircraft refueling stations and hangars, the surface coating industry, wastewater treatment plants, natural gas pipelines and distribution centers, grain handling and storage operations, wood processing areas, and metal surface grinding environments, especially those generating aluminum ash and particulate matter.

3. How IECEx/ATEX Defines Equipment Protection Level (EPL) IECEx/ATEX standards use symbolic and numerical codes to classify different types of hazardous (explosive) conditions and define the likelihood of an explosion under these conditions. Each piece of equipment or device is certified for explosion protection by IECEx/ATEX and assigned and marked with a specific code.

4. Equipment Protection Level (EPL) The EPL describes the level of protection provided by equipment. It is based on an assessment of both the risk from the flammable atmospheric environment and the risk of the equipment becoming an ignition source. According to IEC 60079-0, equipment used in explosive atmospheres containing flammable gases (G) or dust (D) is classified into the following three classes:

Ga or Da: “Very High” protection level, applicable to zones 0 and 20

Gb or Db: “High” protection level, applicable to zones 1 and 21

Gc or Dc: “Ordinary” protection level, applicable to zones 2 and 22

5. GORE® PolyVent Ex+ Code (PMF200400)

The GORE® PolyVent Ex+ code is shown below. These symbols/letters represent equipment rated as Ex level. The remainder of the code indicates the equipment group, category, zone, protection level, and the environment in which the specific equipment can be safely used, as well as the type of protection provided by the equipment.

① ATEX Symbol

Ex Symbol (according to the ATEX Directive)

② Equipment Group

II = Applicable to all above-ground explosive atmospheres

③ Equipment Category (Flammable Atmospheres)

2 = Occasional

3 = Rare, short duration

Category 2 equipment can also be used in areas requiring Category 3.

Corresponding zones: 2G = Zones 1 and 2, 2D = Zones 21 and 22

④ Equipment Environment (Usage Zone)

G = Gas/Mist

D = Dust/Particulate Matter

⑤ Type of Protection

eb = Enhanced Safety

tb = Standard Enclosure Protection

⑥ Ambient Group (II or III)

II = Combustible Gas/Mist

C = Ignites with very little energy (<20 µJ) – e.g., Hydrogen

⇒ IIC is the highest possible level, therefore it covers all other gas groups.

III = Combustible Dust

C = Conductive Material

⇒ IIIC is the highest possible level, therefore it covers all other dust groups.

⑦ Equipment Protection Rating (IECEx Only)

Gb = "High" protection rating, suitable for Zones 1 and 2
Db = "High" protection rating, suitable for Zones 21 and 22

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