Acid Compliance
Compliance & Health · Compliance & Health overview
Acid compliance is the practical evidence case a UK duty-holder maintains to show that exposure to acid mists, alkaline aerosols and corrosive vapours is being managed under the Control of Substances Hazardous to Health (COSHH) Regulations 2002 and against the Workplace Exposure Limits in HSE EH40. This page describes the occupational hygiene side of that case — risk assessment, exposure measurement, LEV evidence, maintenance records and proportionate improvement planning. It is not legal advice, and is not a substitute for the operator's own legal and regulatory review.
What an acid compliance case looks like
In practical terms, a defensible acid compliance case is a small set of documents that, taken together, demonstrate that the employer understands the hazard, has measured the exposure, has the right engineering controls in place, is keeping them working, and is reviewing the case on a defined cycle. The HSE inspector, the insurer and the customer auditor look at broadly the same picture: a current COSHH assessment, current EH40-referenced personal monitoring results, current LEV Thorough Examination and Test reports, the maintenance log, the PPE/RPE programme and the change-control record.
A site that holds all of those documents and can show how they were used to drive proportionate change has a strong compliance position. A site that holds only a generic policy and no measured evidence is exposed regardless of how clean the workshop looks on the day.
- Current COSHH assessment covering each acid process.
- Personal monitoring against substance-specific EH40 limits.
- LEV Thorough Examination and Test under COSHH regulation 9.
- Maintenance, scrubber and consumable records.
- PPE and RPE programme with face-fit and inspection records.
- Change-control log linking process changes to control review.
Acid COSHH assessment
The acid COSHH assessment identifies the substances, the tasks, the foreseeable releases and the population at risk, then judges whether existing controls are adequate against the EH40 limits. On acid duty it is typically substance-specific — sulphuric, hydrochloric, nitric, HF, alkaline aerosol, reactive gas — because the limits and the engineering controls differ. A single generic assessment that bundles all acid work into one paragraph is rarely defensible against a specialist audit.
The assessment is informed by measured exposure where the process is non-trivial and by an engineering judgement on the LEV and supporting ventilation. The output is a written control plan with defined review triggers, not a static document.
Exposure assessment and monitoring records
Personal monitoring at the operator's breathing zone, by a validated MDHS-equivalent method and a UKAS-accredited laboratory, is the central exposure evidence. The compliance file holds the monitoring strategy (BS EN 689 style), the sampling records, the laboratory certificate, the comparison with the EH40 8-hour TWA and short-term limit, the COSHH judgement and the next-step recommendation.
Static and area monitoring may support LEV diagnostics and incident response but is not a substitute for personal sampling for the COSHH judgement. Direct-reading instruments support diagnostics, leak surveys and short-term peak characterisation, and their records sit alongside the laboratory-analysed personal samples.
LEV evidence and ventilation review
All LEV controlling exposure to a hazardous substance is examined and tested at least every 14 months under COSHH regulation 9. On acid duty that examination covers the corrosive-duty hoods, ducting, dampers, fan and discharge, plus scrubber or mist eliminator condition, and is typically read alongside the personal monitoring evidence. A passing LEV test with no recent personal sampling, or recent personal sampling with no current LEV evidence, leaves the compliance case incomplete.
Where the ventilation case is borderline, the proportionate next step is normally a defined engineering or procedural change — hood geometry, push-pull addition, make-up air, scrubber service — captured in the change-control log and verified by re-sampling. RPE upgrades are appropriate as a residual and breakdown control, not as the primary response to a ventilation shortfall.
Maintenance, PPE and RPE records
Maintenance records typically cover scrubber media changes, mist eliminator condition, drain pots, ducting inspections, fan belt and impeller condition, and any reactive work following an LEV finding or process change. PPE and RPE records cover selection rationale (matched to the substance and the residual exposure), face-fit testing for tight-fitting RPE, inspection, storage, training and replacement.
These records are the part of the compliance case that is most often weak in practice and most often probed in audit. A simple, consistent log is more defensible than a thick file that is rarely updated.
Proportionate improvement planning
The improvement plan is where the compliance case becomes a living document. Each personal monitoring round, each LEV examination, each operator concern and each process change feeds an entry in the plan with a defined owner, a defined date and a defined verification step. Borderline exposures are typically scheduled for engineering review and re-sampling on a short interval; well-controlled exposures are scheduled for a longer refresh.
The aim is proportionate continuous improvement — not perfection on the day of audit, but a documented trajectory of measured exposure, engineering review and verified change that any reasonable inspector, insurer or customer would accept as adequate control under COSHH.
When to review acid compliance
Review the compliance case on any change of chemistry, current density, temperature, surface area or throughput; on LEV or building modification; on operator symptom reports or sensitisation concerns (referred to occupational health as a clinical matter); after any spill, scrubber breakthrough or near-miss; after enforcement or insurer audit; and at a defined refresh interval — typically annually for high-hazard chemistries and every two to three years for well-controlled lower-hazard work.
This page is not legal advice and does not guarantee regulatory outcomes. It describes the occupational hygiene evidence pattern that typically supports a defensible acid compliance case in UK practice.
Frequently asked questions
Is this page legal advice on UK acid regulations?
No. This page describes the occupational hygiene evidence pattern that typically supports an acid compliance case under COSHH. It is not legal advice and does not guarantee regulatory outcomes; specific regulatory questions are a matter for the operator's own legal and HSE review.
What are the headline records an acid compliance case relies on?
Typically a current substance-specific COSHH assessment, personal monitoring against EH40 limits, LEV Thorough Examination and Test under COSHH regulation 9, maintenance and scrubber records, the PPE/RPE programme and a change-control log linking process changes to control review.
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