Who is legally responsible for hazardous area classification under ATEX?
Abstract
The employer in control of the workplace. Directive 1999/92/EC makes the employer classify places into zones and record them in the explosion protection document. Consultants or designers may do the work, but the legal duty stays with the employer.
The employer responsible for the workplace. Article 7 of the ATEX workplace directive 1999/92/EC requires the employer to classify places where explosive atmospheres may occur into zones, and Article 8 requires the employer to record them in the explosion protection document (EPD). Consultants, designers and contractors can carry out the classification, but engaging them does not transfer the legal duty.
Short answer
- Duty holder: the employer (in practice the operator of the plant or site), through the national law that transposes Directive 1999/92/EC, for example the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) in Great Britain.
- Who does the work: anyone competent, whether in-house engineers, an engineering contractor or a specialist consultant.
- External help does not discharge the employer: the EU framework directive 89/391/EEC says so explicitly.
- Shared sites: each employer is responsible for matters under its control; the employer responsible for the workplace coordinates and records the coordination in the EPD.
- Before first use: the overall explosion safety of the workplace must be verified by persons competent in explosion protection.
- Equipment manufacturers are responsible for their equipment under Directive 2014/34/EU, not for classifying the user's site.
What the ATEX workplace directive requires
Directive 1999/92/EC is addressed to employers and sets minimum requirements that each Member State puts into national law. The articles that matter here, in plain words:
| Provision | What it requires of the employer |
|---|---|
| Article 4 | assess explosion risks overall: likelihood and duration of explosive atmospheres, ignition sources, the installations and substances, and the scale of the effects |
| Article 6 | where workers of several undertakings share a workplace, each employer handles matters under its control, and the employer responsible for the workplace coordinates the measures and records this in the EPD |
| Article 7 | classify places where explosive atmospheres may occur into zones (Annex I), apply the minimum requirements (Annex II) and mark entrances where necessary (Annex III) |
| Article 8 | draw up the EPD before work starts, showing among other things which places are classified into zones, and revise it after significant changes |
| Annex II, point 2.8 | before first use, have the overall explosion safety verified by persons competent in explosion protection through experience or professional training |
The directive does not say who must hold the pen. It says who must make sure the classification exists, is correct and is kept up to date.
Consultants, designers and contractors
Most classifications are prepared by people other than the employer: the engineering contractor of a new plant, a specialist consultant, or the employer's own process and electrical engineers. That is normal and often the best way to get the competence needed. IEC 60079-10-1 itself includes a clause on the competence of the personnel who carry out a classification.
The legal position does not change. Article 5(2) of the framework directive 89/391/EEC states that where an employer enlists competent external services or persons, this does not discharge the employer from its responsibilities for safety and health. In practice the employer should:
- give the classifier correct process data, substances, operating modes and maintenance practices;
- review and formally accept the classification, and understand its assumptions (ventilation, hole sizes, inerting, detection);
- keep it current when the process, substances, ventilation or layout change;
- make sure equipment selection, inspection and permits to work follow it.
A consultant can of course be liable under contract or civil law for faulty work, and a designer may carry duties under other national rules, but the employer's statutory duty remains.
Practical cases
New plant built by a contractor. The contractor usually delivers the classification drawings with the design. At handover they become the operator's documents: the operator must check that they match the plant as built and as it will be operated, include them in the EPD, and arrange the verification before first use.
Tenant in a leased building. The duty follows the employer whose work creates or is exposed to the explosive atmosphere, not the owner of the building. Where a landlord controls shared services such as ventilation, the arrangements need to be agreed and recorded.
Several employers on one site. During a shutdown, contractors work in classified areas. Article 6 coordination, carried out through permits and site rules, is the responsibility of the employer in charge of the workplace.
Equipment suppliers. A supplier selects the Ex marking of its product, but it is the user's zone, gas group and temperature class that decide whether that product may be installed. A supplier should not be asked to "decide the zone".
Great Britain and other countries
In Great Britain, DSEAR regulation 7 requires every employer to classify places into hazardous and non-hazardous places and the hazardous ones into zones, and requires verification of overall explosion safety by a competent person before first use. HSE guidance adds that hazardous area classification should be carried out as an integral part of the DSEAR risk assessment.
Other EU Member States have their own transposing laws with the same core duty; check the national text for any additional requirements on who may sign or verify. Outside Europe, IEC 60079-10-1 describes the method but does not allocate legal duties; national law does.
Common mistakes
- "The consultant signed it, so it is the consultant's responsibility." The statutory duty stays with the employer.
- Accepting drawings without understanding them. An unexplained ventilation or hole-size assumption can make the whole classification invalid.
- Never revising. The EPD, including the zones, must be revised after significant changes.
- Skipping the verification before first use. It is a separate requirement from the classification itself.
Related on excodex
- The Explosion Protection Document (EPD) and area classification drawings under ATEX 1999/92/EC
- How to carry out a gas hazardous area classification step by step (IEC 60079-10-1)
- What competence does a person need to carry out a hazardous area classification?
- Who can prepare an Explosion Protection Document in Turkey?
- Standards space: ATEX 1999/92/EC
Standards and further reading
- Directive 1999/92/EC (ATEX workplace directive), Articles 4, 6, 7, 8 and Annex II: Article 7 on legislation.gov.uk, Article 8, Article 6, Annex II
- Directive 89/391/EEC (framework directive), Article 5 on the employer's general obligation: legislation.gov.uk
- Dangerous Substances and Explosive Atmospheres Regulations 2002, regulation 7: legislation.gov.uk
- HSE, L138 Dangerous substances and explosive atmospheres, Approved Code of Practice and guidance: hse.gov.uk
- HSE, Area classification for laboratories and small quantities: hse.gov.uk
- IEC 60079-10-1:2020, Classification of areas, explosive gas atmospheres (includes a clause on competence of personnel)
This article is general technical information prepared by the excodex editorial team. It does not replace the applicable standards, the equipment certificates and instructions, national regulations or the assessment of a competent person.