Statutory Inspections · Mandatory · Construction

LEV Thorough Examination and Test Record

The thorough examination and test record for Local Exhaust Ventilation systems provided as a COSHH control measure. Maximum 14-month examination interval for most systems. Covers face velocity measurements, duct velocity, static pressure readings, and comparison against commissioning data. HSE estimates close to 50% of all LEV systems have never been examined. Records retained for 5 years.

Last reviewed: 2 April 2026 — This guide reflects UK law as of this date. COSHH 2002 Reg 9(2) remains current with no amendments enacted as of 2 April 2026. Next scheduled review: 2 April 2027.

Legal basis	Control of Substances Hazardous to Health Regulations 2002 (COSHH 2002), Regulation 9(2)
Examination interval	Maximum 14-month interval between thorough examinations and tests — this allows some flexibility around the 12-month anniversary while ensuring no LEV system goes more than 14 months without examination
Competence	BOHS P601 accreditation is the recognised standard for LEV examiners — strongly recommended by HSE as evidence of competence, though not a strict legal requirement
Key fact	HSE estimates that approximately 50% of LEV systems in the UK have never been thoroughly examined and tested. Non-functional or poorly maintained LEV gives workers a false sense of protection while providing little or no actual exposure control.

1. Why LEV Thorough Examination Matters

Local exhaust ventilation (LEV) is an engineering control used to capture airborne contaminants — dust, fumes, vapour, and mist — at or near the point of generation before they can be inhaled by workers. In construction, LEV systems are commonly used for silica dust extraction during cutting, grinding, and drilling of concrete, stone, and masonry, as well as for welding fume extraction and wood dust extraction. When functioning correctly, LEV is one of the most effective controls available for reducing workplace exposure to hazardous substances.

However, LEV systems degrade over time. Filters become blocked, ductwork develops leaks, fan performance drops, capture hoods are damaged or repositioned incorrectly, and airflow rates fall below the levels needed for effective capture. Without regular thorough examination and testing, these deficiencies go undetected. The system appears to be running — the fan is operating and air is moving — but it may no longer provide adequate control of exposure. Workers continue to rely on a system that is not protecting them.

COSHH 2002 Regulation 9(2) requires employers to ensure that LEV systems are thoroughly examined and tested at intervals not exceeding 14 months. The examination must be carried out by a competent person, and a written report must be produced and retained for at least 5 years. The purpose of the examination is to confirm that the LEV system continues to adequately control exposure to hazardous substances and to identify any defects, deterioration, or modifications that could compromise its performance.

Half of all LEV systems are never examined

HSE's own research estimates that around 50% of LEV systems in UK workplaces have never been thoroughly examined and tested. This means millions of workers are relying on extraction systems that may not be providing adequate protection. If your LEV system has never been examined, arrange one immediately — a system that is not working properly is worse than no system at all, because it creates a false sense of security.

2. Key Components

The following table sets out the key components that a thorough examination and test record for an LEV system must address. Each element demonstrates compliance with COSHH 2002 Regulation 9 and provides the evidence needed to confirm that the system is adequately controlling exposure.

Component	Detail
Site / premises	Address and location of the LEV system within the premises — including the workshop, production area, or site where the system is installed
LEV system description	Full description of the LEV system including type (e.g. on-tool extraction, bench-mounted hood, enclosure, captor hood), manufacturer, model, serial number, and the process or task it serves
Hazardous substance	Identification of the hazardous substance(s) the LEV system is designed to control — e.g. respirable crystalline silica (RCS), wood dust, welding fume, solvent vapour — and the relevant workplace exposure limit (WEL)
Commissioning data	Reference to the original commissioning data including design airflow rates, capture velocities, and static pressures — these are the benchmarks against which current performance is measured
Date of examination	The date on which the thorough examination and test was carried out — this date determines the start of the next 14-month interval
Examiner	Name, qualifications, and employing organisation of the competent person who carried out the examination — BOHS P601 accreditation is the recommended standard of competence
Pre-inspection documents	Review of available documentation including commissioning report, previous examination reports, maintenance records, and any modifications made since the last examination
Visual inspection	Systematic visual inspection of the entire system from capture point to discharge — including hoods, ductwork, dampers, filters, fan, and discharge stack — noting any damage, corrosion, leaks, blockages, or unauthorised modifications
Airflow measurements	Quantified airflow measurements at key points in the system — face velocity or capture velocity at the hood, static pressure at defined points in the ductwork, and airflow volume — compared against commissioning data and design specifications
Assessment	Overall assessment of whether the LEV system is adequately controlling exposure to the hazardous substance — taking account of the visual inspection findings, airflow measurements, and any exposure monitoring data available
Defects	Identification of any defects, deterioration, or deficiencies found during the examination — with recommendations for remedial action and priority (immediate, short-term, or planned maintenance)
Next examination due	The latest date by which the next thorough examination and test must be carried out — must not exceed 14 months from the date of this examination
Record retention	The examination report must be retained for a minimum of 5 years from the date of the examination — this is a legal requirement under COSHH 2002 Regulation 9(5)

3. Common Mistakes

Exceeding the 14-month examination interval

The maximum interval between thorough examinations and tests is 14 months. This is not a target — it is a legal maximum. Many employers treat it as an annual requirement and allow the interval to stretch to 15 or 16 months, particularly around holiday periods or when the examiner is unavailable. Once the 14-month interval has been exceeded, the employer is in breach of COSHH 2002 Regulation 9(2). The system should not be relied upon as an adequate control measure until a valid examination has been completed. Plan examinations well in advance to ensure the 14-month deadline is never missed.

Using an incompetent examiner

The thorough examination and test must be carried out by a competent person. Competence in LEV examination requires specific knowledge of LEV design principles, airflow measurement techniques, filter performance, ductwork losses, and exposure control. A general health and safety consultant or a maintenance engineer may not have this specialist knowledge. HSE strongly recommends that the examiner holds BOHS P601 accreditation (Thorough Examination and Testing of LEV), which is the recognised industry standard. Using an examiner without adequate LEV-specific competence risks producing a report that fails to identify real deficiencies in the system.

4. Frequently Asked Questions

What is BOHS P601?▾

BOHS P601 is a qualification awarded by the British Occupational Hygiene Society (BOHS) that certifies competence in the thorough examination and testing of local exhaust ventilation systems. The P601 module covers LEV design principles, airflow measurement techniques, performance assessment, report writing, and the legal framework under COSHH 2002. Holders of the P601 qualification are recognised by HSE as competent to carry out LEV thorough examinations. While P601 accreditation is not a strict legal requirement, HSE guidance HSG258 (Controlling Airborne Contaminants at Work) strongly recommends it as the benchmark for examiner competence. When selecting an LEV examiner, asking for evidence of P601 accreditation is the most reliable way to verify competence.

Does the 14-month interval apply to all types of LEV?▾

Yes. The 14-month maximum interval applies to all LEV systems provided as a control measure under COSHH 2002, regardless of type, size, or complexity. This includes on-tool dust extraction units, portable extraction units, bench-mounted extraction hoods, spray booth ventilation, welding fume extraction arms, and large centralised dust extraction systems. There is no exemption for small or simple systems. If an LEV system is relied upon to control exposure to a hazardous substance, it must be thoroughly examined and tested at intervals not exceeding 14 months.

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