What to Know First
A part-by-part orientation to common IECEx and ATEX equipment markings.
- Read the marking as a sequence, not as one approval word.
- Use the certificate to interpret every suffix and special condition.
- Accessories and installation must preserve the certified protection.
Illustrative gas-atmosphere marking - not a product nameplate or certificate.
- 01Ex · Explosion Protection
- Indicates that an Ex protection technique is used.
- 02db · Flameproof Enclosure
- Protection type d, with protection level b.
- 03IIC · Gas Group
- Group II gas equipment, subgroup C. This is not a dust marking.
- 04T4 · Surface Temperature
- Maximum 135°C under the certified operating conditions.
- 05Gb · Equipment Protection Level
- A high level of protection for explosive gas atmospheres.
The full nameplate includes the certificate reference and operating limits. An X after the certificate number points to specific conditions of use; U identifies a component requiring further assessment before use.
Marking guidance: IECEx / BARTEC · HBK temperature-class reference
Read from left to right
A typical IEC-style marking identifies the Ex protection concept, equipment group, temperature class or maximum surface temperature, and equipment protection level. Gas and dust markings are different and may both appear.
The nameplate also gives the certificate number, electrical ratings, ambient limits and manufacturer identity.
The small suffixes matter
An ‘X’ after a certificate number means special conditions for safe use apply. A ‘U’ usually identifies an Ex component that is not intended for standalone use.
Do not buy or install equipment marked X without reading those conditions. They may control impact protection, electrostatic risk, cable entry, orientation or ambient temperature.
- Copy the full marking exactly
- Download the certificate from the scheme register
- Read the schedule and special conditions
- Check the installed glands and accessories
A label cannot classify the area
The label states where the equipment may be used; it does not decide what the area classification should be. A competent hazardous-area assessment must identify zones, materials and temperatures first.
Keep the classification drawing and equipment register together.
Project Checklist
IECEx certificate, ATEX marking or the approval required in your country.
Concept such as Ex ia, Ex db, Ex ec or Ex tb.
Group, temperature class, maximum surface temperature and EPL.
Ambient range, IP rating, certificate number and X/U suffix.
Frequently Asked Questions
What does T4 mean?
For gas equipment it is a temperature class. It limits the equipment’s maximum surface temperature under its certified conditions; always check the applicable standard and ambient range.
Official references
Information is based on reviewed sources and our experience at the date shown. Use it at your own risk and verify current codes, certificates and project conditions. Report an issue or suggest a correction.