## Background The EU ATEX Directive 2014/34/EU, which applies to equipment and protective systems intended for use in potentially explosive atmospheres, requires manufacturers to complete conformity assessment and affix the CE mark. The Directive classifies equipment into Group I (mines) and Group II (surface industries), and assigns different zones (Zone 0, 1, 2 or 20, 21, 22) according to equipment category (1, 2, 3). In recent years, EU Notified Bodies (NBs) have become stricter in their review of technical documentation with regard to the reasonableness of area classification, the matching of equipment category to the intended zone of use, and the correspondence between temperature classes and the ignition temperatures of gases/dusts. According to publicly available industry information, the reference CE certification cycle for explosion-proof equipment is 20–45 working days, with a reference cost range of RMB 18,000–60,000, subject to engineer assessment and body scheduling.
## Frontline Observations From recently handled cases, technical documentation that was returned or required supplementary explanation mainly falls into the following categories: 1. **Missing basis for area classification**: Manufacturers did not provide hazardous area classification drawings or explanations for the customer site, and only vaguely marked "for Zone 1," making it impossible for the NB to determine whether the equipment category (e.g., Category 2) matches the zone. 2. **Mismatch between equipment category and zone**: For example, Category 3 equipment used in Zone 1, or failure to consider Category 1D requirements in dust environments, resulting in intrinsic safety design not being recognized. 3. **Mismatch between temperature class and medium ignition temperature**: The maximum surface temperature of the equipment was not verified against gas groups (T1–T6) or dust cloud/layer ignition temperatures, and thermal calculations or test evidence are lacking. 4. **Non-electrical explosion protection overlooked**: Some enterprises focus only on electrical explosion protection (Ex d, Ex e, etc.) and have incomplete risk assessments for non-electrical ignition sources such as mechanical sparks, static electricity, and optical radiation.
The common thread among these issues is that the "intended use conditions" in the technical documentation are disconnected from the actual design parameters of the equipment, preventing the NB from completing the conformity assessment. During the pre-review stage, Shuwang Certification Platform found that about 60% of returned cases could be resolved by supplementing area classification explanations and thermal verification reports, without the need for retesting.
## What Enterprises Should Do Exporting enterprises are advised to complete the following self-checks before submitting for ATEX certification:
| Self-check item | Specific requirements | Common problems | | --- | --- | --- | | Area classification documents | Provide hazardous area classification drawings or written explanations for the customer site | Only verbal notification, no documentary support | | Equipment category matching | Verify the correspondence between Category 1/2/3 and Zone 0/1/2 (or 20/21/22) | Category and zone mismatch | | Temperature class verification | Provide calculation or test reports for the maximum surface temperature of the equipment, compared against gas/dust ignition temperatures | Lack of thermal verification basis | | Non-electrical ignition source assessment | Cover risks such as mechanical sparks, static electricity, and electromagnetic radiation | Only electrical explosion protection assessed | | Completeness of technical documentation | Include risk assessment, drawings, nameplate, instructions, etc. | Inconsistent document versions or missing documents |
For projects already in the certification process, if a request for supplementary materials is received from the NB, priority should be given to confirming the logical consistency between area classification and equipment category, and then supplementing thermal verification or risk assessment reports. Shuwang Certification Platform can assist enterprises in organizing technical documentation preparation and pre-review, and connect with Notified Bodies holding ATEX authorization scope to coordinate rectification and follow-up.
## Notes The cycles and costs described in this article are publicly available industry reference ranges and are subject to engineer assessment and body scheduling. The specific applicable requirements of the ATEX Directive are subject to the official EU text. Shuwang Certification Platform is an export certification solutions service provider and does not engage in testing activities, nor is it a certification body. Testing is completed by partner laboratories with CNAS/CMA or equivalent qualifications, and certificates are issued by EU Notified Bodies (NBs). For further information on the document checklist and process for ATEX certification, please visit https://www.shuwang-cert.com or consult the platform engineers.
**One-sentence conclusion**: ATEX technical documentation returns mostly stem from area classification and equipment category
Don't mismatch; preparing the hazardous area description and thermal verification report in advance can significantly reduce the rounds of supplementary materials.