Inspection Requirements Overview

Inspection Requirements Overview

Installing certified ATEX equipment is only the beginning. Over time, equipment deteriorates—corrosion sets in, seals degrade, cables get damaged, well-meaning but improper repairs compromise protection concepts. EN/IEC 60079-17 establishes inspection requirements to catch these problems before they lead to a failure of explosion protection.

Why Inspection Matters

Equipment that was perfectly safe when installed can become dangerous through normal wear, environmental exposure, or improper intervention. A flameproof enclosure with a corroded flamepath is no longer flameproof. An intrinsically safe circuit with a damaged cable might no longer be intrinsically safe. A cable gland that's worked loose allows moisture and potentially flammable gases into the enclosure. Systematic inspection catches these issues before they result in an incident.

Initial and Periodic Inspection

EN/IEC 60079-17 covers two types of inspection. Initial inspection takes place before commissioning—verifying that the installation matches the design documentation, that equipment is correctly selected for the zone, and that everything is properly installed and connected. Periodic inspection happens throughout the installation's operational life, verifying continued compliance and catching deterioration.

Both types are essential. Initial inspection catches installation errors—wrong equipment in the wrong zone, incorrect cable glands, missing earth connections. Periodic inspection catches the effects of time—corrosion, mechanical damage, thermal degradation, and the consequences of repairs or modifications made since the last inspection.

Inspection Grades

The standard defines three inspection grades based on thoroughness:

• Visual inspection: Identifies defects visible without tools or physical access—damage, corrosion, missing components, incorrect labels, obvious modifications
• Close inspection: Visual inspection plus checks requiring access tools but without opening enclosures—verifying bolts are tight, cable entries are secure, earth bonding appears intact
• Detailed inspection: Close inspection plus opening enclosures and using test equipment—checking internal component condition, measuring earth continuity, verifying insulation resistance, measuring flamepath gaps

The grade required depends on the zone classification, the protection type, and whether it's an initial or periodic inspection. More hazardous zones and more critical protection types demand more thorough inspection.

Inspection Intervals

Zone 0 and Zone 1 installations generally require more frequent inspection than Zone 2. However, the standard doesn't prescribe fixed intervals—actual frequencies must be determined based on equipment type, environmental conditions, manufacturer recommendations, and your own operational experience. Harsh environments (offshore, chemical plants, high humidity) or equipment with known reliability issues may need more frequent attention.

Your Explosion Protection Document should specify the inspection regime: what gets inspected, how often, what grade of inspection, and who's responsible. This creates documented evidence of systematic compliance and makes the programme auditable.

Competence Requirements

Inspections must be carried out by competent persons—people who understand both general electrical safety and the specific requirements for hazardous area installations. They need to recognise what makes ATEX equipment different from ordinary electrical equipment and understand why seemingly minor issues (a missing bolt, a wrong cable gland, a painted flamepath) can be critical to safety.

Competence comes from a combination of professional training and practical experience. It should be verified and documented as part of your safety management system. Several international schemes provide recognised competence certification, including the CompEx scheme (widely used in the oil and gas industry) and the IECEx Certificate of Personnel Competence.

Recording and Following Up

Inspection results must be documented. Records should identify the equipment inspected, the grade of inspection performed, any defects found, the corrective actions taken or recommended, and the inspector's identity and qualifications. Where defects are found, there must be a clear process for follow-up—from isolating dangerous equipment immediately to scheduling repairs within an appropriate timeframe. Employers are responsible for ensuring defects are actually corrected, not just recorded.