Audits

Good audits in explosion protection are not created by simply checking whether documents are present. A meaningful ATEX, DSEAR or explosion protection audit assesses whether an organisation actually controls explosion risks in day-to-day operation. It does not only look at the explosion protection document, the hazardous area classification or existing inspection reports. More importantly, it examines the relationship between design, operation, maintenance, management of change, competence and evidence.

In practice, many companies have individual elements in place, but the system behind them is weak. There may be an explosion protection document, but the latest process modification has not been incorporated. Inspections may have been carried out, but the findings have not been risk-prioritised. A hazardous area drawing may exist, but operators and maintenance technicians may not understand which activities influence release sources, ventilation, dust accumulation or ignition sources. A good audit must identify precisely this gap between documented compliance and operational reality.

The methodology of a good audit starts with a clear definition of the audit objective. Is the purpose to assess compliance with EU ATEX workplace requirements, UK DSEAR obligations, an internal corporate standard, preparation for a regulatory inspection, an insurance review, due diligence, a COMAH or Seveso-related assessment, or a review following an incident, modification or plant extension? The objective determines the depth and focus of the audit. An audit for senior management must clearly identify the main business and safety risks. A technical audit must go deeper into hazardous area classification, ignition source assessment, types of protection, installation quality, inspection status, maintenance and documentation. An audit following a modification must establish whether management of change has worked properly and whether the explosion protection documentation still reflects the plant as operated today.

From experience, an audit only becomes valuable when it does not start with the question “is there a document?”, but with the question “does the protection concept still match the installation as it is currently operated?” To answer that, the auditor must first understand the process. Which substances are used? Where can gases, vapours, mists or combustible dusts be released? Which process conditions are normal and which deviations are realistically foreseeable? How are cleaning, maintenance, filling, emptying, sampling, pumping, conveying, mixing, drying and packaging carried out? Which temporary activities take place? Which changes have been made in recent years? Only then can the auditor assess whether the explosion protection document, hazardous area classification, equipment selection, inspection regime and organisational controls remain technically defensible.

A good audit follows several layers at the same time. The first layer is the documentation review. This assesses whether the explosion protection document, hazardous area classification file, DSEAR assessment or verification dossier is complete, current, traceable and practically usable. It is not sufficient for a hazardous area classification drawing to exist. The real question is whether release sources, ventilation, dust layers, ignition sources, equipment suitability, maintenance, operating instructions, permits to work, emergency measures and management of change are properly assessed and connected. The second layer is field verification. This checks whether the documentation matches the physical installation. The third layer is the management system. This assesses whether the organisation is capable of maintaining explosion protection at a safe and legally defensible level over time. This third layer is what separates a formal paperwork audit from an audit that genuinely reduces risk.

In the chemical industry, the focus is often on the interface between process safety and explosion protection. The auditor must not only look at Ex equipment, but also at process changes, release points, ventilation, inerting, gas detection, sampling points, flanges, pumps, seals, drains, vents and maintenance regimes. Many deviations do not arise because the rules are unknown, but because small technical changes are not consistently translated into the explosion protection document, DSEAR assessment, hazardous area classification or verification dossier. A different medium, a higher process temperature, a changed cleaning solvent or a different pump seal may be enough to undermine the original assessment. A good audit makes these relationships visible without overwhelming the company with abstract legal or standards language.

In the food, feed and powder industries, the reality is different. Electrical ATEX or UKEX equipment is often reasonably well understood, while dust management, cleaning, mechanical equipment and internal explosion risks are less consistently controlled. An audit must therefore consider dust accumulation, extraction systems, filters, elevators, screw conveyors, mixers, tipping points, big-bag stations, cyclones and silos. The question is not only whether Zone 20, Zone 21 or Zone 22 is shown on a drawing. The decisive issue is whether the cleaning frequency, extraction performance, ignition source assessment and mechanical protection measures match the actual product and real operating conditions. With combustible dusts, practical experience is essential, because a plant may look clean on paper while hazardous dust layers accumulate on cable trays, above pipework, on motors, luminaires or structural steelwork. An audit must therefore not remain at document level; it must assess operational practice.

In pharmaceuticals and fine chemicals, the focus is often on management of change, temporary set-ups and product diversity. Laboratories, pilot plants, technical areas and multipurpose installations change frequently. As a result, a hazardous area classification can quickly become outdated when new solvents, powders, batches or cleaning methods are introduced. A good audit assesses whether the system is flexible enough to control those changes safely. It is not enough that an ATEX, DSEAR or explosion protection assessment was once produced. It must be demonstrable how new products are assessed, how temporary equipment is approved, how abnormal operating conditions are controlled and who is competent and authorised to approve changes. In this sector, documentation is often extensive; the audit must establish whether that documentation is actually effective in operation.

In wastewater treatment plants, biogas installations and waste processing facilities, the audit focus is often closer to the practical realities of ageing, corrosion, moisture and incomplete documentation. Methane, hydrogen sulphide, condensate, outdoor installations, older cable systems, corroded enclosures and changed operating modes play a major role. An audit must therefore not only check whether an original hazardous area classification exists, but whether it still matches the current condition of the installation. Pits, pumping stations, sludge treatment, digesters, gas trains, compressors, flares and technical rooms require a different approach from a dry production hall. Experience shows that there is often significant value in restoring demonstrability: current drawings, clear zone boundaries, complete equipment registers, risk-based inspection priorities and realistic maintenance actions.

In energy systems, utilities and battery charging environments, the focus shifts towards hydrogen, ventilation, electrical infrastructure, battery locations, charging behaviour and spatial layout. Many companies underestimate that a battery charging room, standby power installation or battery system is not an ordinary technical room when hydrogen generation or other relevant safety risks have to be considered. The audit must assess whether the ventilation assumptions are valid, whether ignition sources are adequately controlled, whether charging equipment is correctly positioned and whether operation and maintenance reflect actual use. For newer energy applications, it is also important that explosion protection, electrical safety, fire safety and availability are not assessed in isolation.

In storage, transfer and logistics, audits often revolve around activities that take place every day but are not always recognised as explosion-relevant. Loading, unloading, pumping, filling, flushing, venting, sampling, moving IBCs, tank bund management and temporary storage can all affect explosion risks. The audit must therefore pay particular attention to the combination of substance properties, working methods, ventilation, earthing, bonding, electrostatic charging and ignition sources. In this sector, the difference between procedure and practice is often significant. On paper, filling operations may be controlled, while in practice hoses are connected differently, earthing clamps are not checked, containers are changed, or doors and shutters remain open, altering ventilation patterns. A good audit identifies these deviations factually and translates them into practical control measures.

In manufacturing industries, explosion risks are often local and process-specific. Examples include spraying, cleaning, degreasing, bonding, printing, woodworking, metal dust, plastics processing, additive manufacturing and temporary maintenance work. The risk is that explosion protection is seen as something belonging only to the chemical industry, while small local work areas may create relevant explosive atmospheres. An audit must therefore assess whether the organisation recognises where explosive atmospheres may arise and whether local extraction, equipment selection, cleaning, permits to work and training are sufficient. The strength of the audit lies in translating specialist explosion protection requirements into practical controls for the workshop, production area and maintenance department.

The result of a good audit is achieved by assessing and prioritising findings, not merely collecting them. Not every deviation has the same significance. An outdated drawing, a missing certificate, an unclear zone boundary, an open cable entry, an unverified Ex i circuit or recurring dust accumulation each require a different level of priority. The audit report must therefore clearly distinguish between findings that are immediately safety-critical, findings that affect legal or technical demonstrability, items that must be resolved through maintenance and weaknesses that require structural improvement in the management system. Senior management needs controllable risks, maintenance needs concrete corrective actions, and HSE needs defensible evidence for internal audits, insurers and regulators.

An audit only delivers a robust result when findings are linked to ownership. In many companies, explosion protection issues remain open because no one is clearly responsible for the overall system. Engineering owns the drawings, maintenance looks after the installation, HSE maintains the explosion protection document or DSEAR assessment, production changes working practices, and projects implement modifications. Without clear interfaces, fragmentation occurs. A good audit shows where those interfaces are weak. Who assesses a new substance? Who verifies whether a new motor is suitable for the zone? Who updates the explosion protection document or DSEAR assessment after a change? Who closes inspection and audit findings technically? Who decides whether temporary equipment may be used in a hazardous area? By answering these questions, explosion protection becomes manageable.

The quality of an audit is therefore not measured by the size of the report, but by the sharpness of the conclusions. A good audit report connects management and technology. It shows which risks threaten safety, availability, insurability and legal compliance, and which steps are required to regain demonstrable control. In a good audit, the outcome is not a discussion about blame, but clarity on priorities. What must be stopped or made safe immediately? What must be corrected before the next shutdown? What must be included permanently in the maintenance plan? What requires revision of the hazardous area classification, explosion protection document, DSEAR assessment or inspection programme? What must be formally secured within the management of change process?

From experience, the best audit is not a snapshot, but a reliable baseline for improvement. It shows where the company stands, where the system is vulnerable and which actions will have the greatest effect. When this is done properly, the result is not just a list of deviations, but a practical improvement plan. This gives the organisation control over explosion protection across different sectors and installation types, whether in chemicals, food, pharmaceuticals, water treatment, energy, storage, transfer or manufacturing. The value of a good audit lies in translating technical facts into controllable actions. That is what companies need: not formal paper certainty, but demonstrable control of explosion risks in everyday operation.

For the EU context, this text aligns with the ATEX workplace framework under Directive 1999/92/EC and the ATEX equipment framework under Directive 2014/34/EU; for the UK context, it aligns with DSEAR 2002 and the UK equipment regulations for potentially explosive atmospheres. IEC 60079-14:2024 covers electrical installation design, selection, installation and initial inspection, while IEC 60079-17:2023 covers inspection and maintenance of electrical installations in hazardous areas.