How do I ensure ATEX compliance for my installation?

Equipment vs workplace obligations

ATEX compliance is not a single obligation, it is split between two distinct regulatory regimes, each with different duty holders:

A contractor installing ATEX equipment operates under both regimes. They are not a manufacturer (unless they assemble custom equipment), so they are primarily under the Workplace Directive, but they have a duty to verify that the equipment they install is correctly certified. Installing equipment that does not match the zone or the gas group is a Workplace Directive failure, regardless of the equipment's own certification status.

Reading the nameplate

The first step in verifying ATEX compliance is reading and understanding the equipment nameplate. Every certified piece of equipment must carry a nameplate with the following information:

• Manufacturer name and address
• Equipment designation (type, series, or model number)
• CE mark and ⟨Ex⟩ symbol (hexagonal for EU; ⟨UK Ex⟩ for UKCA)
• Equipment group and category, e.g., II 2 G
• Marking string, e.g., Ex eb IIC T6 Gb
• IP rating
• Certificate number, identifies the Notified Body and the examination
• Year of manufacture
• Ambient temperature range, if non-standard (standard is -20 °C to +40 °C)

Check that the zone, gas group, and temperature class on the nameplate are compatible with the installation location. If the certificate number ends in X, obtain the certificate and read the Specific Conditions of Use, they are mandatory.

The technical file

Under 2014/34/EU, manufacturers of Category 1 and 2 equipment must hold a Technical File for each product. The Technical File is not routinely sent to customers, but it must be available to market surveillance authorities on request.

For Category 3 equipment (Zone 2), the Technical File replaces Notified Body examination, the manufacturer self-certifies compliance, so the file is particularly important. The Technical File contains:

• General description of the equipment
• Conceptual design and manufacturing drawings
• Descriptions and explanations of how the protection concept is achieved
• Results of design calculations and examinations
• Test reports (IP testing, temperature rise, mechanical strength)
• List of standards applied
• Declaration of Conformity

As an installer or operator, you do not need the Technical File, but you should hold the Declaration of Conformity and the certificate (or a copy) for each piece of installed equipment.

Installation handover documentation

When a new ATEX installation is commissioned, the contractor should hand over a documentation pack to the site operator. This pack forms the evidence base for ongoing compliance and inspection. A complete handover pack includes:

• As-fitted area classification drawings, updated to show as-installed zone boundaries
• Equipment schedule, list of all installed equipment, including manufacturer, model, certificate number, zone, and location reference
• Certificates and Declarations of Conformity, for every piece of installed certified equipment
• Installation records, inspection reports from initial inspection (per IEC 60079-17), including verification of gland types, torques, and IP integrity
• Intrinsically safe loop documents, for any Ex ia or Ex ib installations: loop calculations, parameter verification, cable records
• Equipment marking photographs, photographic record of nameplates, particularly where access for future inspection is difficult
• Explosive Atmosphere Document, the formal DSEAR risk assessment document

Under DSEAR, the Explosive Atmosphere Document must be produced before work begins in a potentially explosive atmosphere. It must be reviewed and updated whenever changes are made to the installation.

Audit readiness

ATEX compliance is audited by the HSE (in the UK) under DSEAR, and by EU national authorities under 1999/92/EC. Insurance companies increasingly include ATEX compliance in process plant audits. The key areas auditors examine are:

1. Area classification documentation, is there an up-to-date Explosive Atmosphere Document? Do area classification drawings exist and are they current?
2. Equipment verification, for a sample of installed equipment, do the nameplates match the zone? Are certificates available?
3. Installation inspection records, is there evidence of initial inspection? Are periodic inspection records maintained?
4. Management of change, when modifications were made to the installation, was the area classification reviewed? Was modified equipment re-evaluated?
5. Training records, can the operator demonstrate that responsible persons are competent in ATEX requirements?

The most common audit failure is documentation, equipment that is correctly installed and functioning, but where the installation documentation is missing, incomplete, or out of date.

DSEAR and UK compliance

In the UK, DSEAR (Dangerous Substances and Explosive Atmospheres Regulations 2002) implements the ATEX Workplace Directive. Following Brexit, the UK has retained the substantive requirements of DSEAR but operates its own product certification system (UKCA marking) for new products placed on the UK market after January 2025.

Key DSEAR obligations for employers:

• Carry out a DSEAR risk assessment covering all dangerous substances on site
• Classify hazardous areas and produce an Explosive Atmosphere Document
• Implement appropriate measures to eliminate or reduce risk
• Provide suitable equipment (ATEX certified for zones where it is required)
• Provide information, instruction, and training to employees who may be exposed to risk
• Coordinate with contractors working in areas covered by DSEAR

ATEX certificates issued by EU Notified Bodies before 31 December 2020 remain valid for UK market. Products certified after that date must be re-certified for UKCA unless a transition arrangement applies. Consult a competent body (e.g., Baseefa) for current transition guidance.

Managing changes to installations

Changes to ATEX installations, including replacing equipment, modifying processes, or extending installations, trigger fresh compliance obligations. The management of change (MoC) process must include:

• Zone review, does the change affect the zone classification? A new process connection may create or enlarge a Zone 1 area.
• Equipment re-evaluation, is existing equipment still suitable for the (potentially changed) zone?
• Certificate verification for new equipment, is replacement equipment certified to the correct zone, gas group, and temperature class?
• Documentation update, area classification drawings, equipment schedules, and IS loop documents must be updated
• Inspection, new or modified equipment must be subject to initial inspection before energisation

Like-for-like replacement is the simplest case, but even then, the replacement equipment must be checked against the certificate. A replacement terminal box of the same size but a different material or temperature rating may not be a valid substitution.