ATEX in practice: what the marking on a device really tells you

For a category 3 device no examination certificate exists, so the fortnight spent asking for one is not diligence — it is a plant waiting for a part that was always admissible. Read the marking once and the question takes a minute.

Drucktransmitter P10 mit schwarzem Gehäuse und Steckverbinder, Aufdruck IP67 und made in Germany auf dem Typenschild sichtbar

Before you order

The device carries a category. Your area carries a zone.

You are holding a device and someone wants to know whether it may go near a filling point. Your supplier sends a data sheet, your buyer asks for "the ATEX certificate", and nobody mentions that for a category 3 device no such certificate exists.

So a fortnight goes into correspondence about a document the directive never created, while the plant waits for a part that was admissible all along. The mistake is not in the device. It is in the question.

Read the marking with us once, character by character. Afterwards you decide in a minute what a device may do — and which piece of paper is worth asking for at all.

Two directives, two addressees: 2014/34/EU for the maker, 1999/92/EC for the operator
ATEX covers neither fire protection nor ingress protection — an IP68 device can be unfit for a zone
Which zone demands which category is on our page about explosion zones

The marking

Nine characters, read left to right

A complete marking is a sentence made of abbreviations. Read in order, it answers where the device may go, how it protects itself and how hot it is allowed to get.

Read as an example: II 2G Ex db IIC T4 Gb is a device for surface industry, category 2, for gas atmospheres, with a flameproof enclosure tested up to explosion group IIC, whose surface stays below 135 °C.
Segment	What it states	Common values
II	Equipment group — where the device is intended to work	I mining with firedamp · II all other areas
2	Equipment category — the level of protection required	1 (highest) · 2 · 3
G	Type of atmosphere	G gas, vapour, mist · D dust
Ex	The mark for explosion protection itself	—
db	Type of protection plus its protection level	d flameproof enclosure · e increased safety · i intrinsic safety · m encapsulation · p pressurisation · o oil immersion · q powder filling
IIC	Explosion group of the gases the device is tested against	IIA (reference gas propane) · IIB (ethylene) · IIC (hydrogen, acetylene) — IIC covers IIB and IIA
T4	Temperature class — the maximum surface temperature	T1 450 °C · T2 300 °C · T3 200 °C · T4 135 °C · T5 100 °C · T6 85 °C
Gb	Equipment protection level — the residual risk expressed directly	Ga / Gb / Gc for gas · Da / Db / Dc for dust

Wieland RST20i3 Buchsenteil, seitliche Ansicht mit Überwurfmutter und Zugentlastung

Which paper actually exists

"ATEX certified" is not an answer. The category is.

Only category 1 equipment and, among category 2, electrical equipment must pass an EU type-examination by a notified body (2014/34/EU Art. 13). A lawful category 3 device therefore has no examination certificate at all and still carries CE.

Non-electrical category 2 equipment takes a route that surprises most buyers: the maker runs internal production control and deposits the technical file with a notified body. The body keeps that file. It does not assess it.

And IECEx does not replace ATEX. It is a voluntary international scheme, ATEX is European law, and there is no automatic mutual recognition — technically both rest on largely the same standards.

The four-digit number behind CE appears only where the body is in production control (Art. 16(3))
A mechanical Ex part often comes with manufacturer documentation only, and that is compliant
The standards are EN ISO 80079-36 and -37, which replaced the EN 13463 series

Where it goes wrong

Four maintenance moves that cost an approval

Almost never the obvious component. These four account for most of the findings.

A gasket that looks identical
In several types of protection the gasket is part of the protection concept, not an accessory. The approval covers the tested design including the materials named in the certificate — dimensional equivalence is not equivalence.
The cable gland
A flameproof enclosure is only flameproof with the gland it was certified with, correctly sized for the cable actually used. This is the single most common finding in Ex inspections.
Repair without re-inspection
After a repair the equipment has to be checked by a person qualified for the task. German law places that in BetrSichV Annex 2, section 3, no. 4.2; the technical standard for the repair itself is IEC 60079-19.
Missed inspection intervals
Equipment and protective systems every three years, the installation as a whole every six, ventilation and gas detection annually — BetrSichV Annex 2, section 3, nos. 5.1 to 5.3.

Asked at goods-in

Five questions that decide a purchase order

Which equipment category do I need for zone 1?

At least category 2. Zone 0 and zone 20 require category 1, zone 1 and zone 21 at least category 2, zone 2 and zone 22 at least category 3 (Directive 1999/92/EC, Annex II, part A, no. 2.3). A higher category is always permitted, a lower one never — a 3G device must not go into zone 1 under any circumstances.

What does "II 2G Ex db IIC T4 Gb" mean in detail?

Equipment group II (everything outside mining), category 2, for gas atmospheres, protected by a flameproof enclosure at protection level b, tested against explosion group IIC gases such as hydrogen, with a maximum surface temperature of 135 °C, giving equipment protection level Gb. Taken together: usable in zone 1 and zone 2.

Can I order Ex-rated equipment here with the certificates?

Not today: no item in our catalogue is listed as an ATEX-marked variant. shukchok is an open marketplace for industrial goods, and that is exactly the open slot it exists for — a manufacturer or distributor who already issues EU declarations and type-examination certificates lists here, keeps them on the item as product data and ships through the same basket. Until yours does, buy the Ex variant where the paperwork comes with it.

May I fit an equivalent spare part into Ex equipment?

Only if it is the part named in the certificate or one the manufacturer has released as equivalent for that certificate. The approval applies to the examined design including its listed components and materials. A part with the same dimensions from another source is a modification, and the equipment then needs a new assessment.

Is an IECEx certificate enough in Germany?

Not on its own. IECEx is a voluntary international scheme without automatic recognition in EU law. For the EU market the equipment needs CE marking under 2014/34/EU. Because both schemes build on largely the same standards, a manufacturer holding IECEx usually holds the ATEX documentation too — ask for that document, not for the IECEx one.

Where to go from the marking

Two ways in

Buy the standard version here — or bring the Ex version alongside it

Everything outside a zone you can compare and order today, with the specification above the price. And if your workshop builds or trades certified equipment: shelf space next to it is free, because we earn only when one of your positions sells.

See sensors — prices without a login List Ex equipment here

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