LEV Examination
LEV Testing · LEV Testing overview
LEV examination — the Thorough Examination and Test, often abbreviated to LEV TExT — is the formal periodic check required under Regulation 9 of the Control of Substances Hazardous to Health Regulations 2002. It is the mechanism by which UK employers demonstrate that the local exhaust ventilation they rely on to control exposure is still doing the job it was installed to do.
LEV examination and TExT
The Thorough Examination and Test is more than a visual inspection. It is a structured, documented examination of an LEV system's design, condition, performance and use, delivered against the methodology in HSE guidance HSG258. It results in a written report that names every hood examined, records the measurements taken, gives a clear verdict, and identifies any remedial action required.
TExT is the means by which an employer can show — to themselves, to safety representatives, to insurers and to the HSE — that the engineering control they rely on under COSHH is still adequate.
General checks versus formal examination
Day-to-day visual checks by operators, planned filter changes, and routine maintenance by the site team are essential and should not be confused with a formal examination. They keep the system running and catch obvious changes — torn hoses, missing fasteners, damaged hoods, indicator lights showing high filter resistance — but they do not measure capture, transport or discharge against benchmarks.
The formal examination brings together documentation, measurement and observation in one assessment by a competent examiner, and produces a written, signed report. It is the formal record that the COSHH duty has been discharged.
What may be reviewed during examination
The scope of a TExT follows the structure described in HSG258 and is tailored to the system. In practice an examination covers four broad areas:
- Documentation and design intent — commissioning data, the user manual, previous reports, and any record of process changes since the system was installed or last tested.
- System condition — hoods, ductwork, dampers, flexible connections, filters, fans, drives, discharge and any monitoring instrumentation.
- Performance — measured against the original design benchmarks where they exist, and against HSG258 benchmarks where they do not. Typical measurements include hood static pressure, face velocity, capture velocity, duct velocity, filter pressure drop and discharge airflow.
- Use — observation of the system in real operation: operator position, work patterns, whether the system is switched on, and whether informal modifications have changed how it is used.
Why records, condition, airflow and system use all matter
A TExT report that records airflow alone is incomplete. A system can measure within benchmarks at the fan and still fail to control exposure because operators are working outside the capture envelope; conversely, a system used exactly as designed can fail because filters are blinded or a damper has shifted. The four streams above are deliberately combined so that the verdict reflects what the system actually delivers to the breathing zone, not just what the instruments read at a single point.
Documentation matters because without the original design intent, it is much harder to judge whether a measured airflow is acceptable. Where commissioning data is missing, the examiner will reconstruct benchmarks from HSG258 and from the hood geometry — and this should be flagged in the report so the duty-holder knows the basis on which the verdict was reached.
How examination findings help employers prioritise action
A well-written examination report does two jobs. It is a compliance record — proof that the COSHH Regulation 9 duty has been carried out by a competent person at a suitable interval — and it is an action plan. Every finding should be classified clearly: pass, pass with observation, or fail; and every failure should carry a recommended action with an indicative timeframe.
Prioritisation matters because few sites can address every finding immediately. A useful report makes it easy for the duty-holder to distinguish between issues that require urgent action — a non-functioning hood on a Schedule 4 process, for example — and longer-term improvements such as redesigning a hood that is technically passing but only just.
Examination intervals
The default interval under COSHH Regulation 9(2) is at least every 14 months. Certain substances and processes listed in Schedule 4 of COSHH — including some isocyanate, grinding, blasting and rubber-manufacturing operations — require more frequent examination, in some cases every month or every six months.
The 14-month figure is a maximum, not a target. Where a system is heavily loaded, where the process is changing, or where previous examinations have flagged borderline performance, a shorter interval is often the right judgement.
Choosing a competent examiner
HSG258 describes the competence required to carry out an LEV examination: a working knowledge of LEV design, instrumentation and exposure control, plus the ability to interpret what is measured against what the system needs to deliver. In the UK, this is typically demonstrated through BOHS P601 (or equivalent), supported by documented experience and continued professional development.
Competence is not a one-off certificate. A capable examiner combines formal qualification with hands-on familiarity with the system types they are examining, and with the contaminants the systems are controlling.
Frequently asked questions
Is LEV examination a legal requirement?
Where an LEV system is provided to control exposure to a substance hazardous to health, COSHH Regulation 9 requires that it is thoroughly examined and tested at suitable intervals — at least every 14 months, and more frequently for certain Schedule 4 processes. Records must be kept for at least five years.
What is the difference between LEV testing and LEV examination?
In day-to-day use the terms are often interchangeable, and both refer to the Thorough Examination and Test described in HSG258. Strictly, examination covers the inspection and review elements (documentation, condition, use) and testing covers the instrumented performance measurements; together they make up the TExT.
What records should be kept after an LEV examination?
COSHH requires that examination records are kept for at least five years. The report should identify the system and every hood examined, the measurements taken, the verdict on each hood, any remedial actions required, the examiner's name and competence, and the date.
What happens if an LEV system is found to be inadequate?
The duty-holder must take action proportionate to the risk. Depending on the nature of the failure, this may mean immediate repair, interim controls such as additional PPE or process restrictions, or a planned upgrade. The findings should also be reviewed against the underlying COSHH assessment to confirm the existing control approach is still appropriate.
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