ATEX Pneumatic Motors for Hazardous Environments: Underground, Surface, and Normal Use Explained

When an ATEX pneumatic motor is required for a hazardous environment, the wrong certification choice carries serious legal, safety, and financial consequences. Set Makina manufactures both vane type and axial piston pneumatic motors in three distinct certification variants — Underground ATEX, Surface ATEX, and Normal Use — and each must be specified correctly at the time of order. This guide explains exactly what ATEX certification means for pneumatic motors, which variant applies to which environment, and what the mandatory installation requirements are for each.

01What ATEX certification means for pneumatic motors

ATEX is the European regulatory framework governing equipment and protective systems for use in potentially explosive atmospheres. The name derives from the French ATmosphères EXplosibles. Under EU Directive 2014/34/EU — the ATEX Equipment Directive — any equipment intended for use in a classified hazardous zone must carry the appropriate ATEX certification before it is placed on the market or put into service. This is a legal requirement, not a recommendation, across all EU member states and many international markets that follow equivalent standards.

For pneumatic motors specifically, ATEX certification addresses the risk of the motor becoming an ignition source in an atmosphere containing flammable gases, vapours, mists, or dusts. Electric motors carry obvious ignition risks through sparks, brush contact, and motor winding heat. Pneumatic motors eliminate these risks by design — they have no electrical components, no brushes, and no windings. However, they can still generate static electricity through moving parts, and their exhaust heat can, in certain conditions, provide an ignition source if the motor is not correctly specified, grounded, and maintained.

02The three certification variants — and when each applies

Set Makina’s pneumatic motors are available in three variants. The correct variant must be specified at the time of order, as each is manufactured to different requirements. Retrofitting a Normal Use motor to an ATEX environment after purchase is not permissible under the directive.

It is important to note that Surface ATEX certification does not permit use underground, and Underground ATEX certification — while it meets a higher standard — should still be matched to the specific zone classification of the installation. In practice, if there is any doubt about the correct variant for a given site, the ATEX zone classification should be confirmed with the site’s safety officer or a qualified ATEX assessor before ordering.

03ATEX zone classifications and which motor variant applies

The ATEX directive defines hazardous area zones based on the frequency and duration of the presence of an explosive atmosphere. Understanding the zone classification of your installation determines which motor variant is legally required.

04Mandatory installation requirements for ATEX pneumatic motors

Purchasing the correct ATEX motor variant is only the first step. The installation, commissioning, and ongoing operation of an ATEX pneumatic motor in a hazardous environment must also comply with specific requirements drawn directly from Set Makina’s motor manuals and the ATEX directive. Failure to meet these requirements can invalidate the ATEX certification and expose operators to regulatory liability.

• Grounding — mandatory in all ATEX environments

  A grounding connection is mandatory for any ATEX motor installation — both underground and surface variants. The grounding cable must be connected to a bolt on the rear or front of the motor housing, using a bolt that is not already used for mechanical mounting. Before connecting, the paint must be cleaned from the contact surface to ensure electrical continuity between the cable and the bare metal of the motor body.

• Grounding cable specification — minimum 6 mm single-core copper

  The grounding cable must be a single-core, insulated copper cable with a minimum cross-sectional area of 6 mm². This is the minimum specification required to provide reliable static electricity dissipation under the motor’s normal operating conditions. Smaller cables or multi-stranded cables that do not meet this specification are not acceptable for ATEX installation.

• Anti-static paint integrity — inspect and maintain

  ATEX-certified motors are protected with anti-static paint as a fundamental part of the certification. If the motor’s paint surface is chipped, scratched, or otherwise damaged during installation or operation — exposing bare metal — the affected area must be repainted locally as soon as possible using the correct anti-static paint specification. Operating with exposed bare metal in an ATEX environment can invalidate the motor’s certification.

• Air hose specification — minimum ½” Mantex Layflat at 20 bar rating

  All air supply connections for ATEX motors must use hose with a minimum internal diameter of ½” (12.7 mm), rated to at least 20 bar pressure. Mantex Layflat hose or equivalent meeting this specification is required. Undersized or pressure-inadequate hose is a safety risk in ATEX environments and is not compliant with the installation requirements.

• Underground startup procedure — purge at 10% speed first

  In underground environments specifically, before starting the motor at full or working speed, it must first be run at approximately 10% speed to purge any accumulated gases from the immediate motor environment. If the methane concentration in the atmosphere exceeds 10%, the motor must not be started at all. Operators must observe all site warning signals and atmospheric monitoring alarms before commissioning the motor in each shift.

• Continuous lubrication — do not run without oil in the lubricator

  The lubricator at the motor’s air inlet must always contain oil before operation. The motor must not be started if the lubricator is empty. Lubrication failure not only damages the motor but also risks increased internal friction heat — which could potentially compromise the motor’s surface temperature classification (T-class) in an ATEX environment. Check lubricator oil level at the start of every shift.

05Why pneumatic motors are preferred in ATEX environments

Understanding why pneumatic motors are often the preferred choice over electric motors in hazardous environments helps clarify the engineering logic behind ATEX motor selection. The advantage is not simply that pneumatic motors can be certified — it is that they are structurally better suited to these environments by design.

Electric motors in ATEX environments require expensive explosion-proof enclosures, certified cable glands, and complex earthing arrangements. Furthermore, electric motors generate heat in their windings under load — and maintaining the required T-class surface temperature under all load conditions requires careful thermal engineering and monitoring. By contrast, a pneumatic motor contains no electrical components whatsoever. There are no windings, no brushes, no commutators, and no power electronics. As a result, the primary ignition sources that make ATEX certification of electric motors so costly and complex simply do not exist in a pneumatic motor.

Additionally, pneumatic motors are inherently overload-safe — they stall without damage rather than overheating when blocked or overloaded. This means that a fault condition which would cause an electric motor to overheat and potentially reach ignition temperatures results in nothing more than a stopped shaft in a pneumatic motor. Consequently, the total cost of ATEX compliance for a pneumatic motor installation — including the certified motor, correct hose, grounding hardware, and installation labour — is typically significantly lower than an equivalent ATEX electric motor installation.

06Set Makina ATEX pneumatic motors — available for all environments

Both the vane type (ZM / STRC) and axial piston (EP) motor families are available in all three certification variants. The variant must be specified at order — Underground ATEX, Surface ATEX, or Normal Use. Set Makina is the sole authorized service provider for all motors and provides technical documentation supporting ATEX compliance on request.

As this post is part of Set Makina’s pneumatic motor content series, for a full technical comparison of the vane type and axial piston motor families — including torque characteristics, maintenance intervals, and application scenarios — see our complete motor selection guide.

ATEX installation requirements referenced in this article are drawn from Set Makina’s official user manuals for the ZM, STRC, and EP motor families and from EU Directive 2014/34/EU. Zone classification definitions follow EU ATEX classification standards. Site-specific zone classification must always be determined by a qualified ATEX assessor — this article provides guidance only and does not constitute a zone classification assessment. Set Makina is the sole authorized service and certification provider for its pneumatic motor range. Manufactured in Ankara, Turkey, since 1991.