Selecting linear axes for ATEX zones
Why ATEX matters when specifying linear motion
In applications where flammable gases, vapors or dusts may be present, linear motion components must do more than deliver precision and reliability - they must also reduce the risk of ignition. This is where ATEX certified linear axes and linear motion systems play a critical role.
ATEX (derived from ATmosphères EXplosibles) defines the European framework for equipment used in potentially explosive atmospheres. For machine builders and system integrators, selecting a linear axis for an ATEX zone is not just a compliance exercise; it directly influences machine design, safety strategy, and long term operational reliability.
This article outlines the key considerations when selecting linear axes for ATEX zones, including zone classification, certification standards and typical configuration options.
Understanding ATEX zones and equipment categories
ATEX classifies hazardous areas according to how often an explosive atmosphere is present. Linear axes intended for these environments must be designed and certified for the appropriate zone.
Gas atmospheres
Zone 0 – Explosive atmosphere present continuously or for long periods
Zone 1 – Likely to occur occasionally during normal operation
Zone 2 – Unlikely during normal operation, and if it occurs, only briefly
Dust atmospheres
Zone 20 – Explosive dust atmosphere present continuously or frequently
Zone 21 – Likely to occur occasionally
Zone 22 – Unlikely and only for short durations
Most mechanically driven linear axes for hazardous areas are specified for Zone 2 (gas) and Zone 22 (dust), where the focus is on preventing ignition sources under normal operation and foreseeable fault conditions.
Key ATEX standards for linear axes
ATEX compliance for mechanical equipment such as linear axes is defined under the ATEX Directive 2014/34/EU and supported by harmonized standards.
For linear motion systems, the most relevant standards include:
EN ISO 80079 36 – Requirements for non electrical equipment
EN ISO 80079 37 – Types of protection for non electrical equipment
TRGS 727 – Technical Rules for Hazardous Substances (electrostatic hazards)
Certified linear axes typically carry markings such as: II 2G Ex h IIB T4 Gb or II 3D Ex h IIIB T125°C Dc, indicating:
Equipment group and category
Gas or dust suitability
Ignition protection concept (“h” – constructional safety)
Maximum surface temperature
Understanding this marking helps ensure the selected axis is suitable for both the zone classification and the substance involved.
Design considerations for ATEX‑rated linear axes
Selecting a linear axis for an ATEX zone requires more than choosing the right certificate. Practical design factors are just as important.
Drive principle: Toothed belt and spindle‑driven axes are commonly used in ATEX environments. Each offers different benefits depending on load, accuracy and duty cycle requirements.
Surface temperature control: All components must remain within defined temperature limits under normal operation to prevent ignition of surrounding gases or dusts.
Electrostatic discharge prevention: Antistatic materials, conductive toothed belts and controlled grounding paths are critical to reduce electrostatic risk.
Modular configuration: ATEX compliant systems are often built from modular, pre assessed components, allowing flexibility in stroke length, carriage design and mounting without compromising certification.
Accessories with ATEX approval: Limit switches, couplings and sensors must also meet ATEX requirements to ensure the complete axis assembly remains compliant.
Typical applications for ATEX certified linear axes
Linear axes designed for ATEX zones are commonly used in applications such as:
Bottling and filling systems for alcohols and solvents
Chemical and pharmaceutical processing equipment
Paint, coating and surface treatment systems
Handling and positioning of containers with flammable contents
In these environments, the combination of controlled motion, repeatable positioning, and certified ignition protection is essential for safe and reliable operation.
Specification support for hazardous environments
Correct ATEX specification often starts early in the machine design process. Zone classification, substance properties and operating profiles all influence the final axis configuration.
Working with linear motion specialists who understand both mechanical design and ATEX requirements helps reduce risk, avoid over engineering, and ensure documentation aligns with regulatory expectations.
Summary
Selecting linear axes for ATEX zones requires a clear understanding of:
Hazardous area classification
Applicable ATEX directives and standards
Mechanical design principles that minimize ignition risk
By aligning certification, zone requirements and practical design considerations, machine builders can integrate linear motion systems confidently - even in demanding hazardous environments.
Related ATEX and hazardous area motion content
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