Explosive atmospheres cause hundreds of industrial accidents yearly; understanding ATEX zones and compliant equipment is critical to protecting workers, reducing risk, and staying legally compliant.
Key Takeaways
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- What is ATEX and DSEAR? ATEX defines zones and legal requirements, while DSEAR enforces workplace safety; both guide equipment selection and operational controls.
- How are hazardous areas classified? Use EN 60079‑10 to assess substances, likelihood, and duration of explosive atmospheres, then assign gas or dust zones accurately.
- How to maintain ongoing compliance? Perform pre-operation checks, use PPE, schedule inspections, maintain grounding, and keep accurate records of risk assessments and maintenance.
Introduction
ATEX refers to the European regulatory framework for controlling explosive atmospheres in the workplace, covering both equipment and processes. Understanding ATEX zones is critical for manufacturers handling flammable gases, mists, vapours, or combustible dusts. Proper classification ensures safety, compliance, and the correct selection of machinery, particularly in industries such as dairy, FMCG, and chemical manufacturing. Early identification and risk assessment prevent potentially catastrophic incidents and operational downtime.
What is ATEX and Why it Matters
ATEX is the term used to describe the European framework for controlling risks from explosive atmospheres in industrial environments. The name comes from the French “Atmosphères Explosibles.”
In practical terms, ATEX governs how businesses must prevent and control explosions caused by:
- Flammable gases
- Vapours and mists
- Combustible dusts- learn the basics of powder handling here.
- Hybrid mixtures (gas + dust)
For manufacturers operating mixers, mills, dryers, packing machines, or powder handling systems, ATEX is not optional guidance – it is a legal requirement that directly influences:
- Plant layout and zoning
- Equipment specification
- Ignition risk control
- Maintenance regimes
- Worker safety procedures
- Insurance compliance
ATEX consists of two separate but closely linked European Directives: Directive 99/92/EC (ATEX 137 – The Workplace Directive), which focuses on protecting workers in potentially explosive atmospheres, and Directive 2014/34/EU (ATEX 114 – The Equipment Directive), which governs the design, testing, and certification of equipment intended for use in these environments. In this article, we will first cover ATEX 137 in detail, followed by ATEX 114.
Directive 99/92/EC (ATEX 137 – The Workplace Directive)
This Directive focuses on protecting workers who may be exposed to explosive atmospheres.
Under ATEX 137, employers must:
- Identify dangerous substances that could create explosive atmospheres
- Carry out a formal explosion risk assessment
- Classify hazardous areas into Zones (for gases and dusts)
- Eliminate or control potential ignition sources
- Implement technical and organisational safety measures
- Provide appropriate training and information to employees
In simple terms, ATEX 137 is about managing the workplace risk, not designing the equipment, but ensuring the working environment is safe. In Great Britain, these requirements are implemented through DSEAR.
What is DSEAR?
DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002. It is UK legislation that applies ATEX workplace principles into domestic law.
DSEAR requires employers to:
- Assess risks from dangerous substances (including flammable liquids, gases, and combustible dusts)
- Classify hazardous zones
- Reduce risks to as low as reasonably practicable
- Ensure equipment used in zoned areas is suitable
- Prepare emergency procedures
- Provide information and training to employees
Crucially, DSEAR applies not just to large chemical plants, but to everyday manufacturing environments such as:
- Food powder handling
- Nutraceutical blending
- Chemical mixing
- Battery materials processing
- Spray drying and milling operations
Many companies underestimate dust explosion risk because materials are not “obviously flammable.” However, sugar, flour, starch, milk powder, metal powders, and many polymers can form explosive atmospheres under the right conditions.
Why There Is Both DSEAR and ATEX 137
- ATEX 137 is a European Directive (Directive 99/92/EC). It sets the minimum health and safety standards for protecting workers from explosive atmospheres across the EU. Example: ATEX 137 says: “Employers must assess explosion risk and classify zones.”
- DSEAR (Dangerous Substances and Explosive Atmospheres Regulations 2002) is the UK’s domestic legislation that implements ATEX 137. Example: DSEAR says: “In the UK, employers must carry out that assessment, document zones, and implement controls- failure to do so is a legal offence.”
Directive 2014/34/EU (ATEX 114 – The Equipment Directive)
Directive 2014/34/EU, commonly called ATEX 114, applies to manufacturers, suppliers, and importers of equipment and protective systems intended for use in potentially explosive atmospheres.
Its main objectives are to:
- Ensure equipment is designed and constructed to prevent ignition in hazardous areas
- Define essential health and safety requirements for both electrical and mechanical devices
- Require appropriate testing, certification, and conformity assessment before products are placed on the market
- Facilitate free trade of ATEX-compliant equipment across EU member states without repeated testing
In Great Britain, ATEX 114 is implemented via the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016, ensuring that all ATEX equipment meets legal safety standards. The purpose is to ensure equipment can be placed on the market safely and traded freely without additional testing across member states.
Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016
These UK regulations implement ATEX 114 domestically and set legal requirements for any equipment or protective systems used in potentially explosive atmospheres.
Key points:
- Applies to all electrical and mechanical equipment placed on the UK market for use in ATEX zones
- Requires manufacturers, suppliers, or importers to ensure equipment meets essential health and safety requirements
- Mandates testing, certification, and conformity assessment, often through a third-party notified body, though self-certification is allowed for lower-risk zones
- Equipment must be EX-marked to indicate compliance
- Ensures users have sufficient instructions and safety information for proper and safe operation
Explosive Atmospheres in Industrial Manufacturing
An explosive atmosphere is a mixture of dangerous substances with air under atmospheric conditions, in which combustion spreads rapidly after ignition. These atmospheres can arise from:
- Flammable gases, mists, or vapours
- Combustible dusts from powders such as flour, sugar, or wood
| Property | Gases/Vapours/Mists | Dusts |
|---|---|---|
| Ignition source sensitivity | High | Moderate to High |
| Explosion speed | Rapid | Can propagate slowly then accelerate |
| Persistence in environment | Variable | Often settles, can re-suspend |
| Common industrial examples | Solvent mixing, vehicle paint spray | Flour milling, chemical powders |
Internal link for further reading: The Risks of Combustible Dust & Powder Handling
Understanding how processes like mixing, milling, filling, and powder handling create hazards is essential for proper risk management and equipment selection.
ATEX Zone Classifications Explained
ATEX zones classify areas based on the likelihood and persistence of explosive atmospheres:
Gas Zones:
- Zone 0: Explosive atmosphere present continuously or for long periods.
- Zone 1: Likely to occur in normal operation.
- Zone 2: Not likely in normal operation and short duration if it occurs.
Dust Zones:
- Zone 20: Dust present continuously or for long periods.
- Zone 21: Likely during normal operation.
- Zone 22: Not likely during normal operation; short duration if it occurs.
For engineers and safety managers, knowing how powders can ignite and accumulate is essential; our article on The Risks of Combustible Dust & Powder Handling covers this in detail.
Risk Assessment & Area Classification Workflow
Proper risk assessment and area classification are the foundation of ATEX compliance. Following a structured workflow ensures that explosive hazards are identified, zones are accurately defined, and the correct equipment is selected. The process aligns with EN 60079‑10 standards for gas and dust atmospheres.
1. Identify Hazardous Substances
Begin by cataloguing all flammable or combustible materials present in the process or workplace, including:
- Gases and vapours – solvents, cleaning agents, fuel gases
- Dusts – powders, flour, sugar, wood, polymers, metal powders
Consider both stored materials (silos, tanks) and process-generated materials (milling, mixing, conveying). Record the chemical or physical properties, including flashpoint, particle size, moisture content, and ignition sensitivity. This information is critical for accurate hazard evaluation.
2. Determine Likelihood and Duration of Explosive Atmospheres
Evaluate how and when an explosive atmosphere could form:
- Likelihood: How often is the substance present in a form that can ignite?
- Duration: Will the atmosphere be present continuously, intermittently, or rarely?
This step informs the zone classification. For example:
- Continuous or long-term presence → Zone 0 (gas) or Zone 20 (dust)
- Likely during normal operation → Zone 1 (gas) or Zone 21 (dust)
- Unlikely or short-term → Zone 2 (gas) or Zone 22 (dust)
Document observations from process analysis, sampling, and historical incident records to support your assessment.
3. Assign Zones Based on Gas or Dust Properties
Using EN 60079‑10 guidance, match the likelihood and duration of explosive atmospheres to the appropriate zone:
- Gas zones: Zone 0, 1, 2
- Dust zones: Zone 20, 21, 22
How to assign zones:
- Combine substance properties (flashpoint, lower explosion limit, particle size) with operational conditions
- Consider ventilation, temperature, humidity, and potential ignition sources
- Use risk matrices or software if available to standardize assignments
Tip: Zones are spatial. Identify areas around tanks, mixers, filling lines, powder handling points, and confined spaces, not just rooms.
Once hazardous areas have been classified, those zones must be communicated clearly across technical drawings, site plans, and equipment documentation. ATEX zone drawings are the standard method for doing this – they map where explosive atmospheres may exist, define boundaries, and tell engineers and operators exactly which equipment category is required in each area.
Understanding how to read these drawings is essential for anyone involved in procurement, installation, maintenance, or safety auditing.
Zone Marking Conventions
Each zone is represented by a distinct hatching or fill pattern on technical drawings. These visual conventions allow engineers to immediately identify the risk level of any given area at a glance.
| Zone | Type | Pattern Used | Risk Level |
|---|---|---|---|
| Zone 0 | Gas | Dense cross-hatch | Continuous – highest risk |
| Zone 1 | Gas | Circular dot pattern | Intermittent – normal operation |
| Zone 2 | Gas | Diagonal lines | Occasional – short duration |
| Zone 20 | Dust | Small squares (dense) | Continuous – highest risk |
| Zone 21 | Dust | Vertical lines | Intermittent – normal operation |
| Zone 22 | Dust | Grid pattern (light) | Occasional – short duration |
ATEX Zone Drawings as a Living Document
A zone drawing is not a static document. It must be reviewed and updated whenever:
- Process materials or quantities change
- New equipment is installed or relocated
- Ventilation or extraction systems are modified
- A DSEAR risk reassessment is carried out
Treating zone drawings as a living document ensures that equipment selection, maintenance schedules, and contractor briefings always reflect the current state of the facility — and keeps you legally compliant under DSEAR and the 2016 EPS Regulations.
Practical Tip: All zone boundaries should be physically marked on-site with EX signage, and the corresponding drawing should be readily accessible to operators, maintenance teams, and any contractors working in or near hazardous areas.
4. Document Findings and Mark Zones
Accurate documentation is legally required under DSEAR and critical for safe operations.
- Produce a zone plan showing all classified areas and boundaries
- Include zone numbers, substance types, and risk levels
- Ensure physical signage is installed at entry points, using the ATEX EX symbol and zone number
- Maintain records for audits, inspections, and maintenance planning
Proper documentation ensures everyone, from operators to contractors, knows where hazards exist.
5. Select Appropriate ATEX-Certified Equipment
Once zones are defined:
- Select equipment rated for the specific zone (Category 1, 2, 3)
- Verify EX marking, protection method, and certification (EN standards / ATEX 114 / 2016 EPS Regulations) mmm
- Consider compatibility with the process — for example, explosion-proof motors in Zone 1 mixers or dust-tight conveyor systems in Zone 21
- Ensure installation follows manufacturer instructions and does not introduce new ignition sources
Practical Tip: Reassess periodically or after process changes. Any alteration in materials, process flow, or ventilation can change zone classifications and equipment requirements. Keeping your risk assessment up to date prevents non-compliance and reduces explosion risk.
Key ATEX Equipment Compliance Checks for Buyers
Ensuring equipment is ATEX-compliant is critical for safety, legal compliance, and reliable operation in hazardous areas. Before purchasing, buyers must confirm that machinery is rated for the correct zone, properly certified, and installed according to manufacturer guidance.
All of our equipment can be specified for Atex zones and is available to view on our website.
A good starting point is to check the equipment category, which indicates the level of protection required for the zone it will operate in:
- Category 1: High protection, suitable for Zone 0/20
- Category 2: Medium protection, suitable for Zone 1/21
- Category 3: Basic protection, suitable for Zone 2/22
Once the category is confirmed, the following compliance checks should be carried out to ensure the equipment is safe, suitable, and legally compliant. When sourcing equipment inform your supplier of the atex zone the equipment will be operating in.
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EX Marking
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Look for the “EX” symbol clearly on the equipment plate or body, this confirms the machine is certified for use in explosive atmospheres. Confirm the equipment is rated for the specific zone where it will be installed.
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Should include:
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Equipment category (1, 2, 3)
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Zone suitability (0, 1, 2, 20, 21, 22)
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Type of protection (e.g.,
d,e,i)
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Conformity Assessment / Certification
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Check for certificates issued by a recognized Notified Body, or self-certification if allowed for lower-risk zones.
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Ensure the certificate references ATEX 114 / 2016 EPS Regulations.
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Certificates should match the specific model, configuration, and installation type.
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Type of Protection / Protection Method
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Equipment must use an approved method to prevent ignition in explosive atmospheres. Common protection types include:
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Ex d – Flameproof enclosure
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Ex e – Increased safety
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Ex i – Intrinsic safety
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Ex t – Protection for dust zones
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Documentation & Instructions
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The supplier must provide clear instructions for installation, operation, and maintenance.
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Includes ambient conditions, permissible atmospheres, grounding, and inspection intervals.
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Material & Construction
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Materials must be suitable for the environment (e.g., corrosion-resistant, robust enclosures).
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Check seals, fasteners, and any parts that could generate sparks.
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Maintenance & Inspection Requirements
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Confirm inspection intervals and maintenance procedures in line with the zone rating.
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Equipment should allow for safe maintenance without compromising ATEX compliance.
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Compatibility with Existing Systems
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Check that the equipment does not introduce new ignition sources to the existing hazardous area.
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Ensure proper integration with ventilation, dust extraction, and grounding systems.
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Tip for Buyers: Always verify EX marking, certificate, zone, and protection type together. A mismatch between category, zone, or protection type is the most common compliance issue in industrial installations.
Verification, Maintenance, and Ongoing Compliance
Maintaining ATEX compliance is not a one-time exercise. Even after a facility is correctly zoned and equipped, ongoing verification and maintenance are critical to prevent ignition hazards, protect staff, and stay legally compliant under DSEAR and the 2016 EPS Regulations.
1. Pre-Operation Checks
Before starting any process in a hazardous area:
- Confirm equipment compliance: Ensure all machinery is ATEX-certified, correctly rated for the zone, and properly installed.
- Check zoned areas: Make sure all hazardous zones are clearly marked with EX signage at entry points and boundaries.
- Verify safety systems: Ensure grounding, ventilation, and explosion relief systems are operational.
Why it matters: Even a single piece of non-compliant equipment or unmarked zone can create a serious ignition risk.
2. Personal Protective Equipment (PPE)
Employees working in ATEX zones must have suitable anti-static protective gear, including:
- Clothing that prevents static discharge
- Footwear compatible with the zone rating
- Gloves and head protection as required
Why it matters: In dust and gas zones, electrostatic discharge is one of the most common ignition sources. Proper PPE protects staff and reduces overall risk.
3. Maintenance and Inspections
Regular maintenance ensures equipment continues to operate safely in explosive atmospheres:
- Inspect equipment for wear, corrosion, or mechanical damage
- Clean dust accumulation on surfaces and in ventilation ducts
- Verify grounding systems and electrical connections are intact
- Check that protective devices, such as flame arrestors or pressure relief systems, function correctly
Recommended practice: Schedule maintenance intervals based on manufacturer instructions and zone severity. For example, Category 1 equipment in Zone 0/20 may require more frequent checks than Category 3 equipment in Zone 2/22.
Why it matters: Even certified equipment can become unsafe if neglected, potentially creating an ignition source in a high-risk environment.
4. Documentation and Record-Keeping
Maintain accurate records of:
- Risk assessments and hazardous area classifications
- Verification checks of equipment and signage
- Maintenance and inspection schedules
- Training logs and PPE issuance
Why it matters: Documentation demonstrates compliance to regulators, supports audits, and helps track trends that could indicate increasing risks. It also ensures continuity if personnel change or if processes are updated.
Practical Tip: Conduct periodic verification audits to ensure all ATEX measures remain effective, especially after process changes, new equipment installations, or facility modifications.
Conclusion
ATEX and DSEAR compliance is essential for safety, operational continuity, and legal adherence in industrial environments with flammable gases, vapours, or dusts. By understanding hazardous zones, selecting certified equipment, and implementing robust verification and maintenance processes, manufacturers can significantly reduce the risk of explosions while protecting employees and assets.
Frequently Asked Questions
What is ATEX and why is it important?
ATEX consists of two EU Directives: ATEX 137 (workplace safety) and ATEX 114 (equipment standards). Together they guide hazard assessment, zone classification, and equipment compliance.
What is DSEAR?
DSEAR is the UK regulation implementing ATEX 137, requiring employers to identify risks from explosive atmospheres and take preventive measures in the workplace.
How are hazardous areas classified?
Using EN 60079‑10, areas are classified by the type of hazardous substance, likelihood, and duration of an explosive atmosphere, then assigned zones (0,1,2 for gases; 20,21,22 for dusts).
What does EX marking on equipment mean?
The EX mark indicates ATEX-certified equipment suitable for specific zones and categories, showing compliance with protection methods and safety standards.
What are the ATEX equipment categories?
Category 1: High protection for Zone 0/20
Category 2: Medium protection for Zone 1/21
Category 3: Basic protection for Zone 2/22
How often should ATEX equipment be inspected?
Inspection intervals depend on zone and category, but regular pre-operation checks, scheduled maintenance, and cleaning of dust/ventilation are essential to maintain compliance.
What personal protective equipment is required in ATEX zones?
Anti-static clothing, footwear, gloves, and head protection are required in dust or gas zones to prevent electrostatic discharges and reduce ignition risks.
What is the Explosion Pentagon?
An explosion requires five elements: fuel, oxidant, ignition source, confinement, and dispersion. Removing any element prevents an explosion and informs risk control measures.
How should hazardous zones be documented?
Zones must be recorded in risk assessments, marked with EX signage, and kept updated to reflect any process or layout changes for audit and safety purposes.
Can existing equipment continue to be used in ATEX zones?
Yes, if verified safe through risk assessment and maintenance, but all equipment must comply with the appropriate ATEX category and protection method.