ATEX, IECEx and the North American Class/Division system all describe the same physics, but they are not interchangeable paperwork. Which one you need is decided by where the equipment is being installed — and buying the wrong certificate is a common and expensive way to fail an inspection.
The confusion usually starts because the technical standards underneath are now largely the same. The difference is in the approval route, the marking, and who accepts what.
The three systems at a glance
| ATEX | IECEx | North America (Class/Division & Zone) | |
|---|---|---|---|
| Region | European Union | International (IEC member countries) | United States and Canada |
| Legal basis | Directive 2014/34/EU, mandatory for the EU market | Voluntary international certification system | National Electrical Code (NEC) and Canadian Electrical Code |
| Technical standards | EN 60079 series | IEC 60079 series | UL, FM and CSA standards, derived from the same physics |
| Marking | CE plus the Ex hexagon, e.g. II 2 G Ex db IIC T6 Gb | Ex db IIC T6 Gb, with an IECEx certificate number | Listing mark from UL, FM or CSA with class, division or zone |
| Issued by | EU Notified Body | Approved IECEx Certification Body (ExCB) | Nationally Recognised Testing Laboratory |
ATEX: two directives, not one
ATEX is often spoken about as a single thing, but the name covers two separate directives, and buyers regularly mix them up.
- Directive 2014/34/EU is the equipment directive. It applies to the manufacturer, and it is why a product carries the CE mark and the Ex hexagon. It replaced the older 94/9/EC.
- Directive 1999/92/EC is the workplace directive, sometimes called ATEX 137. It applies to the user, and it is the obligation to classify areas, select suitable equipment and manage the installation.
The equipment marking adds the ATEX category ahead of the IEC-style string. Categories map to zones for gas:
| ATEX category | Permitted zones | Comparable EPL |
|---|---|---|
| 1 G | Zone 0, 1 and 2 | Ga |
| 2 G | Zone 1 and 2 | Gb |
| 3 G | Zone 2 | Gc |
So II 2 G Ex db IIC T6 Gb reads as: equipment group II (surface industry), category 2 (Zone 1 and 2), for gas, following the Ex marking that says flameproof, group IIC, T6, EPL Gb.
IECEx: international, and increasingly the default
IECEx is not a law. It is a certification system run by the IEC, in which approved certification bodies issue certificates against the IEC 60079 series. Its value is that the certificate is internationally recognised and, crucially, publicly verifiable.
The IECEx system also extends beyond equipment: there are schemes for service facilities and for certified persons, which matters when a plant requires a documented competence trail for hazardous-area work.
The practical advantages for a project are:
- one certificate accepted as evidence in many countries, reducing repeated testing;
- a public certificate register, so an inspector or buyer can check authenticity directly;
- a common technical basis with ATEX, since both rest on the IEC 60079 series.
Some countries accept IECEx directly; others use it as a fast track into a local approval. That is why most export-oriented manufacturers carry IECEx and ATEX together and add local approvals where they matter commercially.
North America: two parallel systems
The United States and Canada historically use a Class and Division system, and the NEC also permits an alternative Zone system that aligns with IEC practice.
| System | Division / Zone | Where it applies |
|---|---|---|
| Class I, Division 1 | Hazardous atmosphere present under normal conditions | Roughly comparable to Zone 1 |
| Class I, Division 2 | Present only under abnormal conditions | Roughly comparable to Zone 2 |
| Class II | Combustible dust | Dust environments |
| Class III | Ignitable fibres and flyings | Textile and similar plants |
| Class I, Zone 0 / 1 / 2 | NEC Article 505 alternative | Uses IEC-style protection concepts |
Equipment must be listed or approved by a recognised body such as UL, FM or CSA for the specific class, division or zone. A CE-marked ATEX product is not automatically accepted in the United States, and an IECEx certificate on its own does not make it acceptable either.
The mapping between Division 1 and Zone 1 is often described as “roughly equivalent”, and that word matters. They are different schemes with different test regimes and different marking conventions. If your project is in North America, state it at the enquiry stage.
Local approvals that sit on top
Beyond the three main systems, many markets require a national approval before equipment can be imported or installed. These are commercially decisive but are often discovered late.
| Market | What is commonly required |
|---|---|
| European Union | ATEX equipment directive, CE marking |
| United Kingdom | UKEX scheme, UKCA marking |
| India | PESO approval |
| Brazil | INMETRO certification |
| Russia and Eurasian Economic Union | EAC certification under the customs union technical regulation on equipment for explosive atmospheres |
| China | Domestic Ex certification for equipment placed on the Chinese market |
| Saudi Arabia and much of the Gulf | IECEx or ATEX as the technical basis, plus national import approval |
| Australia and New Zealand | IECEx widely accepted, with the local regulatory mark |
Treat this table as a starting point, not a legal opinion: the requirement is set by the local authority, and it changes. Confirm with your importer or the authority before the order is placed rather than after the container lands.
Why a manufacturer holds both ATEX and IECEx
For the buyer, a dual-certified product is a sign that the test programme was run once against a standard that satisfies two systems. It usually means the same hardware is acceptable across more projects, which simplifies spares, and it removes the risk of a project being supplied against a certificate the end user’s inspector will not accept.
It does not mean the two certificates are identical documents, or that one proves the other. Both should be produced on request. Our own documentation is listed on the quality and certifications page.
What to write into a purchase specification
- The installation country, and the market the equipment must be approved for.
- The area classification: zone, group, temperature class, ambient range.
- The certification system required — ATEX, IECEx, UKEX, UL listing, or a national approval.
- A requirement to supply the certificate itself, with its number and issuing body, for the exact model quoted.
- A requirement that the certificate be verifiable in the issuing system’s public register.
Point 4 is the one worth insisting on. A datasheet statement that the range is “certified to ATEX” tells you nothing about whether the specific variant you are buying is covered. See how to verify an explosion-proof certificate for the checking procedure.
Common questions
Is IECEx accepted in Europe instead of ATEX?
No. For equipment placed on the EU market, the ATEX equipment directive is mandatory and the product must carry CE marking. An IECEx certificate is useful technical evidence and can support the assessment, but it does not replace the ATEX route.
Is ATEX accepted in the United States?
Not on its own. Hazardous-location equipment for the US market must be listed or approved by a recognised body for the applicable class, division or zone under the NEC.
Can one product carry ATEX and IECEx at the same time?
Yes, and it is common. Both certificates describe the same equipment against the same IEC 60079 protection concepts, issued through different systems. Ask for each certificate separately.
Where can I check whether an IECEx certificate is real?
Issued IECEx certificates, reports and licences are public and searchable in the IECEx On-Line Certification System. The system itself is described at iecex.com.
Tell us the installation country and we will tell you which approvals apply. Send the destination, the area classification and the equipment list — we will confirm the certification needed before you commit to a specification.
