Work at Height in an ATEX Zone: What Must the Contractor Comply With?

You are commissioning work at height in a plant where the zone classification has already been completed, the occupational health and safety documentation is stored in a drawer, and the ATEX inspector has signed the protocol. The problem appears when it turns out that the rope access company you have been hiring for the past few years does not have a single certificate for working in potentially explosive atmospheres. They enter the facility with standard equipment, without procedures, and without an intrinsic safety review. If nothing happens, you are lucky. If an incident occurs, you are responsible as the person supervising the work on site.

This article explains what working in an ATEX zone actually means for an external contractor and what you have the right — or, more precisely, the obligation — to require before allowing anyone into a potentially explosive atmosphere.

What Is an ATEX Zone and How Is It Classified?

ATEX is an abbreviation of the French term “ATmosphères EXplosibles,” meaning explosive atmospheres. ATEX zone classification defines places where an explosive atmosphere may occur due to the presence of gases, vapours, mists, or dusts. This classification is regulated by Directive 1999/92/EC, also known as ATEX 137, and by national regulations on minimum occupational health and safety requirements in hazardous environments.

For gases, vapours, and mists, a three-level classification applies:

•Zone 0: an explosive atmosphere is present continuously or for long periods. An example is the inside of a tank containing a flammable liquid.

•Zone 1: an explosive atmosphere may occur during normal operation. An example is the area around ventilation openings of fuel tanks.

•Zone 2: an explosive atmosphere does not occur under normal conditions, but if it does, it persists only briefly. An example is the surroundings of a gas installation in an open area.

For combustible dusts, an analogous classification applies:

•Zone 20: a dust cloud is present continuously or for long periods, for example inside silos, conveyors, or mills.

•Zone 21: a dust cloud may occur during normal operation, for example directly around filling points.

•Zone 22: a dust cloud does not occur under normal conditions or persists only briefly.

Zone classification is prepared by an installation designer or qualified expert, and the results are included in the Explosion Protection Document. As the facility manager, you are required to have an up-to-date Explosion Protection Document, and it is on this basis that you must define requirements for every external contractor.

In places such as the interiors of tanks, professional washing and deposit removal must be preceded by rigorous atmosphere testing and forced ventilation.

Legal Requirements: The ATEX Directive and Polish Regulations

Directive 2014/34/EU, known as the ATEX Equipment Directive, regulates the design and manufacture of equipment intended for use in explosive atmospheres. Every device and tool brought into the zone must have CE marking with the relevant category number and the Ex symbol, confirming that the equipment has been certified by a notified body.

From the perspective of work organization, the key regulations are:

•Directive 1999/92/EC, known as the ATEX Workplace Directive, implemented in Poland through national regulations, which imposes on the employer the obligation to assess risk, classify zones, and ensure that every task in an ATEX zone is carried out in accordance with the Explosion Protection Document.

•The regulation on general occupational health and safety provisions, which defines general requirements for particularly hazardous work, including work in potentially explosive atmospheres.

•Technical Inspection Authority requirements, applicable to pressure systems and tanks classified within ATEX zones.

From a practical point of view, if you commission an external contractor to work in an ATEX zone, you are obliged to provide them with current zone documentation, inform them about the risks, and make sure that they have the competencies and equipment appropriate for the zone. Failure to verify the contractor is not a mitigating circumstance. It is a violation of regulations by the client.

What Certifications Must the Company and Equipment Have?

When an industrial rope access company is to enter an ATEX zone, you should require documentation in three areas.

Personnel competencies: technicians should have training in working in potentially explosive atmospheres, meaning ATEX training that covers at least the principles of zone classification, basics of electrostatics and intrinsic safety, rules for selecting Ex equipment, and emergency procedures. The training should be documented with a current personal certificate.

Certification of rope access equipment: ropes, harnesses, descenders, carabiners, and other elements of the fall protection system must have declarations of conformity with the ATEX category appropriate to the zone in which they will be used. Equipment for Zone 1 or Zone 20 will have different requirements than equipment for Zone 2 or Zone 22. Particular attention must be paid to materials and the risk of electrostatic discharge. Ropes with a synthetic core may accumulate charges if they are not selected for Ex conditions.

Certification of tools: every electrical, pneumatic, or hand tool brought into an ATEX zone must be certified for that zone. Standard tools, even if described as “safe,” do not meet the requirements. This applies to vacuum cleaners, impact tools, lighting, phones, and radio transmitters.

Safe Entry Procedures for an Ex Zone

Equipment certification is a necessary condition, but it is not sufficient on its own. Work in an ATEX zone must be organized according to strict operating procedures.

Permit to work: this is a formal document issued by the person responsible for the zone before any work begins. The permit defines the scope of work, duration, conditions for entering the zone, required protective measures, team composition, and emergency procedure. Without a valid permit to work, no contractor should cross the boundary of the hazardous zone.

Atmosphere testing before entry: before entering the zone, gas or dust concentration must be measured by a qualified person using a certified Ex detector. The measurement result is recorded in the protocol.

Intrinsic safety in practice: this means eliminating every potential ignition source. It includes a ban on bringing in uncertified electronic equipment, the use of grounding and equipotential bonding during work, a smoking ban, mandatory anti-static clothing, and checking footwear for ESD compliance.

Supervision and communication: work in ATEX zones requires external standby supervision by a person outside the zone who can respond immediately in an emergency. Communication inside the zone must take place using certified Ex equipment or visual signals.

Documentation after completion: the completion protocol should include the list of people involved in the work, the equipment used with serial numbers and certificate validity dates, atmosphere measurement results, information about zone conditions during the work, and the signatures of the work supervisor and the person responsible for the zone.

What to Check Before Choosing a Contractor

Before signing the work order, ask the contractor for the following documents:

•current ATEX training certificates for every technician assigned to the work;

•a list of rope access equipment with Ex declarations of conformity and certificate validity dates;

•a sample permit-to-work procedure used by the company;

•an example protocol from completed work in an Ex zone;

•civil liability insurance covering work in ATEX zones.

A company that cannot provide these documents at the quotation stage is not ready to work in a potentially explosive atmosphere, regardless of its price or availability.

If you are planning work at height in an ATEX zone and want to make sure that the contractor meets your plant’s requirements, ask about the scope of qualifications and equipment documentation before setting the date. Verification at the beginning is many times cheaper than explanations after an incident.