📌 3 Key Takeaways
- A gas detector installed in a hazardous area must carry explosion-proof (Ex) certification. An uncertified unit can itself become an ignition source from even a tiny spark.
- Korea requires KCs certification for domestic sites, IECEx is used for exports and international projects, and ATEX is required for the European market — each scheme differs in its legal basis and scope of recognition.
- Learning to read the Ex marking on a device (e.g., Ex d IIB T6 Gb) lets you make a first-pass check on whether it fits your site's hazardous area classification.
Before you evaluate a gas detector's performance for a hazardous area, there is something else to check first: explosion-proof certification. A gas detector is meant to warn workers of dangerous gas early, but if its internal electrical circuitry is not built to an explosion-proof standard, the detector itself can become the ignition source for an accident. This article covers what the KCs, IECEx, and ATEX certification schemes actually mean, how to read the Ex marking printed on a device, and how to work out which certification your site needs.
Why Explosion-Proof Certification Matters — The Risk of Uncertified Equipment
A hazardous area is a location where flammable gas, vapor, or dust may mix with air at an ignitable concentration. Typical examples include oil and chemical plants, paint booths, confined spaces in wastewater treatment plants, and LNG/LPG storage facilities. In these environments, even a tiny spark at a switch contact or overheating on an electrical device surface can trigger an explosion. Explosion-proof certification is the process by which a national or international authority tests and verifies that a piece of electrical equipment is designed and built so it will not become an ignition source in such conditions, and occupational safety and health regulations require electrical equipment installed in hazardous areas to undergo explosion-proof performance certification.
KCs, IECEx, ATEX — What's the Difference?
All three schemes share the same goal — verifying the safety of electrical equipment for hazardous areas — but they differ in their legal basis and where they are recognized.
KCs — Korea's Domestic Explosion-Proof Certification
KCs is a domestic Korean certification issued by accredited testing and certification bodies under Korea's occupational safety and health regulations. In principle, electrical equipment installed or sold for hazardous areas at a domestic worksite must hold KCs certification (or an equivalent domestic performance certification).
IECEx — The International Electrotechnical Commission's Mutual Recognition Scheme
IECEx is an international certification system under the International Electrotechnical Commission (IEC), built around the idea that a single set of test results can be mutually recognized across member countries. For a manufacturer exporting to multiple countries at once, this reduces the burden of repeating separate national tests, which is why IECEx is often required for international projects and multinational plants.
ATEX — The European Union's Explosion Protection Directive
ATEX certification is based on EU Directive 2014/34/EU and is required to sell hazardous-area equipment within the European market. While its test requirements overlap significantly with IECEx, its legal basis and marking method (CE mark + Ex symbol) are separately defined, so products destined for Europe need ATEX certification checked separately.
| Category | KCs | IECEx | ATEX |
|---|---|---|---|
| Legal basis | Korean occupational safety and health regulations | IEC international mutual recognition scheme | EU Directive 2014/34/EU |
| Scope | Domestic Korean sites | Mutual recognition among IECEx member countries | European Economic Area (EEA) |
| Issuing/recognizing body | Accredited domestic testing/certification bodies | IECEx-accredited certification bodies (ExCB) | European Notified Bodies |
| Key marking | KCs mark + Ex symbol | IECEx certificate + Ex symbol | CE mark + Ex symbol |
| Needed when... | Installing/selling at a domestic worksite | Exporting to multiple countries, international projects | Entering the European market |
※ This table summarizes the general structure of each scheme. Actual certification status and scope can vary by product model and issue date — please contact WANDI directly to confirm the current certification for a specific model.
How to Read the Ex Marking Printed on a Device
A certified explosion-proof device is marked with a code such as "Ex d IIB T6 Gb." Each part means the following.
- Ex — Indicates the equipment is explosion-protected
- d, ia, e, p, etc. — The type of protection (e.g., d = flameproof enclosure, ia = intrinsic safety, e = increased safety)
- IIA, IIB, IIC — Gas group (explosion hazard class). IIC is the strictest class and covers high-risk gases such as hydrogen.
- T1–T6 — Maximum allowable surface temperature class. T6 is the lowest (85°C or below), suited to gases that ignite even at low temperatures.
- Ga, Gb, Gc — Equipment protection level. Ga offers the highest level of protection.
Being able to read this code lets you make a first-pass check, from the catalog alone, on whether a device suits your site's hazardous area zone (Zone 0, 1, or 2) and gas type. The final suitability decision, however, should always be confirmed against the original certificate together with WANDI's technical team.
Which Certification Does Your Site Need? — A Checklist
- First decide whether the equipment will be installed only at a domestic site, or whether it's for an international project or export.
- Confirm which hazardous area zone (Zone 0, 1, or 2) the installation site falls under.
- Confirm which gas group (IIA, IIB, IIC) the handled gas belongs to (hydrogen, acetylene, etc. require IIC-rated equipment).
- Confirm the equipment's temperature class (T-code) is rated below the ignition temperature of the surrounding gas.
- For multinational orders or overseas delivery, check IECEx certification separately; for Europe, check ATEX/CE marking.
- Check the validity period and testing body on the certificate, and always keep a copy of the original.
Closing
Explosion-proof certification isn't a nice-to-have — it's the minimum safety standard a gas detector must meet before it goes into a hazardous area. Whether it's KCs for a domestic site, IECEx for an international project, or ATEX for entry into Europe, confirming the certification that matches your site's location and use case before purchasing equipment is the surest way to prevent an accident. For questions about explosion-proof certification or help configuring a gas detection setup for your site, contact WANDI at +82-31-340-6952.