Подготовка поверхности в ATEX Zone 1: требования и одобренные методы

This guide explains what ATEX zone 1 means for surface preparation: the legal framework, how zones and equipment categories match, how to read an ATEX marking, why blasting and grinding are restricted, and which tool configuration and safe system of work allow coating maintenance to continue in a live hazardous area.

In explosive atmospheres such as operating offshore platforms, active refineries, LNG terminals and petrochemical plants, open abrasive blasting is rarely an option while the plant is live. High-velocity abrasive striking steel produces impact sparks and hot particles that can ignite a flammable gas or vapour atmosphere, so most operators treat it as hot work that is only allowed once the area has been made gas-free under a hot-work permit.

Yet these are precisely the environments where maintenance of protective coatings is most critical. Offshore structures in corrosive marine atmospheres, refinery piping in hydrogen sulphide service and LNG plant structural steel subject to cryogenic temperature cycling all require periodic coating maintenance, often in areas where the standard surface preparation method cannot be used without shutting the process down.

The ATEX / IEC 60079 regulatory framework

Equipment for use in explosive atmospheres is regulated by two frameworks that are technically aligned:

• In Europe: the ATEX Equipment Directive 2014/34/EU (often called ATEX 114) covers equipment and protective systems, and the ATEX Workplace Directive 1999/92/EC (ATEX 137) covers the protection of workers, including the classification of hazardous areas into zones. Equipment placed on the EU market for use in these areas must meet the Equipment Directive and carry the corresponding marking.
• Internationally: the IEC 60079 series of standards, adopted in whole or in part by many jurisdictions, including the US Zone system in NEC Article 505, Canada, Australia and the Gulf states. Many international operators reference IEC 60079 or ATEX in their global equipment standards.

In North America, hazardous locations are classified either by the traditional Class/Division system or by the Class/Zone system introduced in NEC Article 505. An Article 505 Zone 1 corresponds to IEC/ATEX zone 1.

Understanding zone classification

Directive 1999/92/EC defines gas zones 0, 1 and 2 and dust zones 20, 21 and 22, and sets which equipment categories may be used in each.

Zone 1 is the most operationally critical zone for coating maintenance because it covers the active process areas of a facility: the areas that must remain in service and that are often most exposed to corrosive conditions.

Why abrasive blasting and grinding are restricted in zone 1

The ignition risk of abrasive blasting comes from mechanical impact. When steel grit, garnet or mineral abrasive strikes steel at high velocity, part of the kinetic energy is released as heat, producing incandescent impact and friction sparks. The energy and temperature of these sparks can be enough to ignite flammable vapour-air mixtures within their explosive range. Blasting also generates static charge on hoses and nozzles, which must be controlled by bonding and earthing.

A specific hazard in refineries and offshore is the thermite spark. It occurs when metallic aluminium, for example aluminium alloy smears or aluminium-pigmented paint, is struck against rusty steel: the aluminium reacts with the iron oxide (2Al + Fe₂O₃ → Al₂O₃ + 2Fe) and releases very hot particles. Aluminium oxide abrasive is itself already oxidised and does not undergo this reaction, but any impact process on rusty steel near light-alloy material needs to consider it.

For these reasons, operators normally do not allow open abrasive blasting in a live zone 1. Where blasting is unavoidable, the usual route is to isolate and gas-free the area and work under a hot-work permit for the duration of the job.

Angle grinders present a similar problem. Standard electric angle grinders are not designed for zone 1, and a high-speed abrasive disc against steel produces friction sparks and local heat, so grinding is also normally handled as hot work.

What an ATEX marking means for surface preparation tools

Under Directive 2014/34/EU, non-electrical equipment of group II, category 2, is placed on the market after an ignition hazard assessment and internal production control by the manufacturer, with the technical documentation lodged with a notified body. The relevant standards are IEC 60079-0 (general requirements) and, for non-electrical equipment, EN ISO 80079-36 and EN ISO 80079-37. The marking conveys specific information:

The Bristle Blaster® Pneumatic in zone 1

The Bristle Blaster® Pneumatic from MontiPower® is fully pneumatic, with no electrical components. It has undergone an independent ignition hazard analysis and an ATEX 2014/34/EU conformity evaluation as Category 2 equipment for zone 1 explosive gas (group IIA, EPL Gb) and zone 21 explosive dust (group IIIC, EPL Db), assessed to EN ISO 80079-36, EN ISO 80079-37 and IEC 60079-0. MontiPower documentation gives the gas marking as II 2G c IIA T4 X, applying to specific Bristle Blaster® belts in combination with the original Bristle Blaster® Pneumatic drive unit only.

The same tool gives a surface cleanliness comparable to ISO 8501-1 Sa 2½ / SSPC-SP 10 and a 65–85 µm Rz (2.6–3.3 mil) anchor profile on standard API 5L steel in documented tests. Results vary with steel grade, rust grade, belt and technique, and acceptance is set by the coating specification and the inspector. That combination of a hazardous-area evaluation and a blast-comparable result is what makes it relevant for zone 1 coating maintenance.

The ATEX evaluation does not mean that wire tips on steel can never produce a spark. It means that, used with the specified belts, drive and special conditions (the "X"), the equipment has been assessed as meeting the Category 2 requirements for the stated gas group and temperature class. MontiPower's own safety guidance notes that mechanical preparation on steel can produce sparks; whether work can go ahead is decided by the site operator's zoning, risk assessment and permit system. See surface preparation safety and sparkless surface preparation.

Typical zone 1 applications include:

• Offshore platforms: splash zones, risers, process deck structural steel and flare boom structures
• Refineries and petrochemical plants: in-service maintenance, turnaround work and repairs under insulation, within the IIA gas group limit
• Onshore pipeline facilities: field joints and coating repairs at stations and in corridors classified as hazardous areas
• LNG terminals: structural steel adjacent to process equipment, pipe supports and bund area structures

Operational requirements for zone 1 surface preparation work

A suitable ATEX evaluation of the tool is necessary but not sufficient. Surface preparation in zone 1 needs a complete safe system of work that includes:

• Permit to work. Zone 1 maintenance requires a formal hazardous-area work permit (typically a cold-work permit for a tool used within its ATEX conditions). The permit defines the scope, the zone classification and gas group, the monitoring, emergency procedures and authorised personnel. Include the tool's ATEX documentation and the special conditions of use in the permit package.
• Continuous gas monitoring. A calibrated portable gas detector, itself suitable for the zone, should be worn throughout the work. Many operators set the alarm at or below 10% LEL, with work stopping immediately if it activates; follow the site procedure.
• Air supply. The compressor supplying the Bristle Blaster® Pneumatic should be located outside the hazardous area, or be suitable for it. Route the air hose away from traffic, sharp edges and hot surfaces.
• Personal protective equipment. Safety glasses or a face shield, hearing protection selected from the noise data in the operating manual, cut- and impact-resistant gloves, antistatic footwear, a dust mask or the respiratory protection set by the risk assessment, and flame-resistant coveralls where the site policy requires them.
• Authorised supervision. Work in zone 1 must be supervised by a person authorised for hazardous-area work under the facility's safety management system.

Selecting the right configuration for your zone 1 application

For a side-by-side view of the drives, see Bristle Blaster® vs. sandblasting.

For the step-by-step preparation and verification procedure, see our guide on how to achieve SSPC-SP 10-comparable results without sandblasting. For the full definition of SSPC-SP 10 and its verification requirements, see our SSPC-SP 10 complete technical guide.

Frequently asked questions

Is there any abrasive blasting method approved for ATEX zone 1?

Open abrasive blasting on steel produces impact sparks and static, so operators normally treat it as hot work and only allow it in a zone 1 after the area is isolated, made gas-free and covered by a hot-work permit. Verify any claim of a spark-free blasting method against the equipment's ATEX documentation and the site risk assessment before relying on it.

What is the difference between ATEX zone 1 and NEC Class I Division 1?

They do not map one to one. Class I Division 1 covers both IEC zone 0 and zone 1, while Division 2 corresponds to zone 2. Category 2G equipment is therefore not acceptable in every Division 1 location. Under NEC Article 505, which uses zones, zone 1 equipment is accepted in zone 1 areas. Always check the facility's area classification drawings.

Do I need a different tool for ATEX zone 2?

No. Directive 1999/92/EC allows category 1, 2 or 3 equipment in zone 2, so Category 2 equipment suitable for zone 1 may also be used in zone 2. The Bristle Blaster® Pneumatic can therefore be used in zone 1 and zone 2, within its gas group IIA, temperature class T4 and special conditions of use.

Can the Bristle Blaster® Pneumatic be used in dust zones?

The Bristle Blaster® Pneumatic is ATEX-evaluated for zone 21 explosive dust (group IIIC, EPL Db) as well as zone 1 gas. Zone 21 permits category 1 or 2 equipment, and zone 22 also permits category 3. As with gas, the special conditions of use and the site permit system apply, and removed material should be collected rather than allowed to accumulate.

What documentation should I have on site in zone 1?

Keep the EU declaration of conformity and ATEX documentation for the drive unit and belts in use, the operating manual containing the special conditions of use behind the X marking, and the facility's permit-to-work documents. Contact MontiPower® for the current documentation that matches your tool configuration and belt type.