Updated: May 2026
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Author: Veress Árpád · Explosion-protection expert
Ex audit (site inspection)
An Ex audit is the on-site expert review of an explosion-hazard plant: it checks whether the equipment, the documentation and the practice comply with the law and the standards, and uncovers gaps before an authority — or an incident — does.
What is an Ex audit?
In practice, "Ex audit" covers two related things: the periodic inspection of explosion-protected equipment (per MSZ EN 60079-17), and the conformity review of the whole plant — including the documentation, the zone classification and the practice. The goal is to prove conformity and uncover gaps.
What does it examine? (MSZ EN 60079-17)
The standard distinguishes three depths of inspection:
- Visual inspection — faults detectable by looking (damage, a missing bolt, corrosion).
- Close inspection — beyond the visual, elements checkable up close with a tool (e.g. looseness).
- Detailed inspection — a check requiring the equipment to be opened or a measurement taken.
The inspection covers, among others, the correct Ex marking and category, sealing, cable entries, earthing and equipotential bonding, and the currency of the equipment register.
Typical gaps — top 10
The most frequently uncovered conformity gaps:
- Out-of-date documentation — reality no longer matches the paperwork.
- The zone classification did not follow the technology change.
- Equipment of the wrong category in a zone.
- Missing or incomplete equipment register.
- Damaged or incomplete cable entry (loss of sealing).
- Missing or undocumented earthing/equipotential bonding.
- Expired or omitted periodic inspection.
- Unevaluated ignition sources (static electricity, mechanical sparks).
- Incomplete cleaning regime in dust zones (settled dust).
- Missing or out-of-date training and work instructions.
How often is it mandatory?
Explosion-protected equipment must be inspected regularly, at intervals determined on a risk basis; in addition, an initial inspection is mandatory at first commissioning. The precise frequency is determined by the equipment, the environment and the zone — this too must be recorded in the inspection plan.
From the field
In practice
- Location
- a multi-site manufacturer with a mixed Ex inventory.
- What we found
the equipment register lived in Excel but had not been updated for two years; for several devices there was no trace of the periodic inspection.
- Why it matters
without inspection, the existence of the protection cannot be proven — which at an inspection is just as much a gap as if the protection were genuinely absent. By organising the register into a system (ATEXdb), the inspections became traceable.
Downloadable audit checklist
Ex audit on-site checklist (PDF) — along the top 10 gaps, so you can quickly assess where your plant stands. Download →
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Frequently asked questions
What is the difference between an Ex audit and a periodic inspection?
The periodic inspection is the regular, standard-based check of the equipment; the Ex audit is broader, reviewing the conformity of the whole plant from the documentation to the practice.