ATEX vs IECEx: Choosing a Certified Engine Starter for Hazardous Areas

In an explosive atmosphere, the device that starts your engine cannot be the thing that sets off an incident. ATEX and IECEx are the two frameworks that prove a starter is safe to use in those conditions. Here is what each one means, how they differ, and how to choose the right certified starter.

Anywhere flammable gas, vapour or dust can be present, equipment has to be certified safe for that environment. On oil and gas installations, in mining and across petrochemical sites, that requirement extends to engine starting. Getting the certification right is not optional, so it pays to understand the two schemes you will keep meeting: ATEX and IECEx.

What Is ATEX?

ATEX takes its name from the French for explosive atmospheres, ATmosphères EXplosibles. It refers to the European Union directives that govern equipment intended for use in potentially explosive atmospheres. Within the EU and the UK, ATEX certification is a legal requirement for equipment used in classified hazardous zones, and products are marked accordingly with the equipment group, category and zone they are approved for.

What Is IECEx?

IECEx is the international scheme operated by the International Electrotechnical Commission. Rather than being tied to one region's law, it provides a globally recognised certificate of conformity for equipment used in explosive atmospheres. Many operators outside the EU, and an increasing number worldwide, ask for IECEx certification because it is accepted across multiple countries without separate national approvals.

ATEX vs IECEx: The Practical Difference

The two schemes are built on closely aligned technical standards, so a product engineered for one is often certified to both. The difference is largely about where, and under whose authority, the certification applies.

In short, ATEX answers a regional legal requirement, while IECEx answers an international one. If you are exporting equipment or working across borders, you will often want both. You can read more on our ATEX engine starting systems and IECEx certified engine starters pages.

Why Pre-Engaged Starters Suit Hazardous Areas

The detail that matters most for hazardous area duty is how the starter engages the engine. A pre-engaged starter brings its pinion into full mesh with the ring gear before the motor turns, so the gears are locked together before any cranking force is applied. That avoids the tooth clash of an inertia starter, where a spinning pinion is thrown into the ring gear, and with it the friction and sparking that the engagement can produce. In an explosive atmosphere, removing that ignition source is exactly the point, which is why a pre-engaged starter is the key choice for ATEX duty.

It also pairs naturally with non-electric drive. A starter powered by compressed air or hydraulic pressure has no electrical supply and no spark to manage, so a pre-engaged, non-electric starter keeps ignition risk down on both fronts, before certification is even discussed.

ATEX Approved Hydraulic Starters

Within the M-Series, the M22 and M28 hydraulic starter motors are offered in ATEX approved, pre-engaged form, pairing high cranking torque with hazardous area certification for engines on offshore and onshore installations.

Pneumatic Starters for Hazardous Areas

For applications with a compressed air or gas supply, pneumatic starters are the long-standing choice in hazardous environments, valued for their reliability in extreme temperatures and their suitability for certified duty.

Choosing a Certified Starter

To specify with confidence, confirm the following before selecting a starter:

• The hazardous zone the equipment will operate in.
• The gas group and temperature class required for the site.
• Which scheme your operator requires, ATEX, IECEx, or both.
• The available power source and the engine's torque requirement.

If any of those are unclear, it is always better to confirm than to assume. The certification has to match the site, not just the engine.