1. Hazard Identification (Zone Classification Errors)

Typical failures:

• Incorrect or outdated hazardous area classification
• Misunderstanding of gas/vapour/dust groups (IIA/IIB/IIC, IIIA/IIIB/IIIC)
• Ignoring ventilation, confinement, release grades
• Relying on as-built drawings instead of real field conditions
• No integration of process data (temperature, pressure, LEL, flashpoint)
• Overlooking non-electrical ignition sources (hot surfaces, mechanical friction)

2. Risk Evaluation (Ignition Risk Assessment Errors)

Typical failures:

• Wrong assumptions on T-class / maximum surface temperature
• Not considering normal vs. abnormal conditions
• Ignoring equipment protection levels (EPLs) and required safety margins
• Underestimating dust layer thickness and thermal ignition
• Treating probability of failure subjectively
• Not evaluating electrostatic hazards (powders, liquids, clothing)

3. Control Measures Plan (Design & Selection Errors)

Typical failures:

• Selecting wrong Ex technique (Ex e vs Ex d vs Ex t vs Ex nR, etc.)
• Installing non-compatible accessories (glands, adapters, reducers)
• Missing ingress protection requirements (IP54/IP66)
• No coordination between electrical + mechanical + instrumentation
• No consideration of ambient temperature ranges → wrong T-class
• Missing certificates or using invalid/incomplete certificates
• Not verifying equipment suitability for the specific zone + EPL

4. Documentation & Communication Errors

Typical failures:

• Not maintaining a properly structured Ex Register
• Certificates saved without:
• ATEX DoC
• EU Type Examination Certificate
• Instructions/User manuals
• No linkage between equipment → location → zone classification
• Poor communication between engineering, operations, maintenance
• Generic checklists not adapted to site/process
• Using translated certificates instead of originals

5. Review & Update Errors (Inspection & Maintenance)

Typical failures:

• No compliance with IEC 60079-17 inspection cycles
• 36 months (continuous operation)
• 12 months (mobile)
• 6 months (heavy duty / severe conditions)
• Only "visual" inspections → no close/detailed inspection
• Not updating the Ex register after:
• equipment replacement
• repairs
• modifications
• Ignoring findings or not closing "repeat nonconformities"
• Missing proof of competence for inspectors (IEC 60079-17, -19)

6. Continuous Improvement Errors (Organisational Weaknesses)

Typical failures:

• No formal Ex competency framework (training → assessment → refresh)
• No change management for Ex areas (MOC)
• Ignoring lessons learned from:
• near misses
• fires/explosions
• equipment failures
• No ownership: engineering blames maintenance, and vice versa
• Leadership not demonstrating Ex culture / commitment
• No digitalisation → information is lost between teams

Keep up good work!

Arpad
veress@exprofessional.com