What does LEV stand for?

LEV stands for Local Exhaust Ventilation — engineered systems (hoods, ducts, fans, filters) that capture airborne contaminants at source before they reach a worker's breathing zone.

How often is LEV testing required in the UK?

COSHH Regulation 9 requires a Thorough Examination and Test (TExT) of LEV systems at least every 14 months. Higher-risk processes (asbestos, blasting, some metalworking) require more frequent testing — typically 6 months.

Who can perform LEV testing?

LEV testing must be carried out by a competent person — typically a BOHS P601 qualified examiner. The test report must include hood face velocities, duct transport velocities, static pressures, filter performance and a verdict against the system's commissioning standard.

LEV Testing: UK Regulations, Requirements & Frequency (COSHH Reg 9)

What LEV is, and what it isn't

LEV is engineering control: a captor hood, ductwork, air mover (fan) and discharge (often with filtration) that removes contaminant at source, before it enters the worker's breathing zone. Examples: welding fume extraction, soldering snorkels, woodworking dust extract, paint-booth backdraught, lab fume cupboards, kitchen canopy hoods (which sit at the intersection of LEV and TR19).

General room ventilation, recirculating air cleaners, and PPE (RPE) are not LEV. Under COSHH's hierarchy of control, LEV outranks RPE — RPE is the last line, not the substitute.

The legal requirement

COSHH 2002, Regulation 9 requires that engineering controls (including LEV) are subject to a Thorough Examination and Test (TExT) at suitable intervals — and the standard interval is at least every 14 months. Records must be kept for at least 5 years.

Schedule 4 of COSHH lists processes with shorter mandatory intervals (typically 6 months) — including blasting of castings, jute processing, and certain non-ferrous metal grinding.

Failure to maintain and test LEV is one of the most common HSE enforcement findings in manufacturing — improvement notices and prohibition notices follow routinely.

What a TExT actually involves

A competent LEV examiner performs three linked steps:

Thorough visual examination — physical condition of hoods, ductwork, dampers, fans, filters, discharge points
Measurement — hood face/capture velocities, duct transport velocities, static pressures, filter pressure drop, motor current
Comparison against commissioning data — the system's original performance baseline (or HSG258 benchmark in its absence)

Results are documented in a TExT report with a clear pass/fail verdict per hood, plus remedial actions and a recommended re-test interval.

Who can examine LEV — competence requirements

HSG258 (HSE's Controlling airborne contaminants at work) defines competence. In practice, the recognised UK qualification is BOHS P601 — Initial Appraisal and Thorough Examination and Testing of LEV Systems. Examiners should be independent of installation and maintenance contractors where possible to avoid conflict of interest.

What inspectors find

Hoods positioned too far from the source (capture velocity collapses with distance squared)
Flexible duct kinks and crushed sections reducing transport velocity below settling thresholds
Filters never changed — pressure drop unmonitored
Systems modified (extra branches added) without rebalancing
No commissioning data, so no baseline to test against
RPE used to compensate for poorly-performing LEV — a Reg 9 failure

LEV Testing: Requirements, Regulations and the 14-Month Rule

What LEV is, and what it isn't

The legal requirement

What a TExT actually involves

Who can examine LEV — competence requirements

What inspectors find

Need a TExT or LEV competence review?

LEV Testing: Requirements, Regulations and the 14-Month Rule

What LEV is, and what it isn't

The legal requirement

What a TExT actually involves

Who can examine LEV — competence requirements

What inspectors find

LEV in the wider regulatory stack

Need a TExT or LEV competence review?