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LEV Testing Under COSHH
How Often Does LEV Need Testing? A Guide to Thorough Examination Under COSHH
In Great Britain, local exhaust ventilation (LEV) must be thoroughly examined and tested by a competent person at least once every 14 months under Regulation 9 of the Control of Substances Hazardous to Health Regulations 2002 (COSHH). Some processes must be tested every 1 or 6 months, and the records must be kept for at least five years.
LEV is one of the most common ways of controlling exposure to dust, fume, mist, vapour and gas at work. It is also one of the easiest controls to get wrong without anyone noticing. Hoods get moved, ducts get damaged, filters clog and fans wear, and the system can keep running and making noise while no longer protecting anyone.
That is why the law requires LEV to be examined and tested on a fixed cycle. This guide explains how often that needs to happen, what the test involves, who can carry it out and what you need to keep on file.
What is LEV and when do you need it?
Local exhaust ventilation is an engineering system that captures airborne contaminants at the point where they are released, before they reach the breathing zone of workers. A typical system has five parts: a hood or enclosure, ducting, an air cleaner or filter, a fan and a discharge point.
Common examples include:
Welding and soldering fume extraction
Dust extraction on woodworking, grinding and cutting machinery
Spray booths and paint-spray rooms
Laboratory fume cupboards
Downflow booths for weighing and dispensing powders
Mobile or portable extraction units
Under COSHH, employers must first try to eliminate or substitute a hazardous substance. Where that is not reasonably practicable, engineering controls such as LEV come next, ahead of respiratory protective equipment (RPE). Your COSHH assessment should identify where LEV is needed and what it is expected to achieve.
How often must LEV be thoroughly examined and tested?
At least once every 14 months for most LEV systems, under COSHH Regulation 9. Four types of processes
carry a shorter legal maximum, set out in Schedule 4 of COSHH:
Process | Minimum frequency |
Blasting carried out in, or incidental to, the cleaning of metal castings in connection with their manufacture | Every 1 month |
Jute cloth manufacture | Every 1 month |
Dry grinding, abrading or polishing of metal articles (other than gold, platinum or iridium) using mechanical power, in any room for more than 12 hours in any week | Every 6 months |
Processes giving off dust or fume in which non-ferrous metal castings are produced | Every 6 months |
Source: COSHH 2002, Schedule 4.
The 14-month figure is a maximum, not a target. Your COSHH assessment may justify more frequent examination where the system handles corrosive or abrasive contaminants, runs heavily, or protects workers from substances that can cause serious disease, such as respirable crystalline silica or hardwood dust.
Is it 12 months or 14 months?
The legal maximum in Great Britain is 14 months. Many organisations book LEV testing every 12 months because it fits neatly into an annual maintenance calendar, and that is perfectly sensible. But a test carried out at 13 months is still compliant, and one carried out at 15 months is not.
The extra two months exist to give flexibility in scheduling, not to be used as a buffer by default. If your last examination was carried out in October, the safest approach is to book the next one for the same time next year.
What does a thorough examination and test involve?
A thorough examination and test (often shortened to TExT) is a detailed check that the LEV is still performing as designed and still controlling exposure. HSE guidance HSG258 sets out how it should be carried out, in three stages:
Thorough visual examination. The examiner checks every part of the system for damage, wear, corrosion, blockages and leaks, including hoods, ducting, filters, the fan and the discharge.
Measurement of technical performance. Air velocities and static pressures are measured at hoods and in ducts and compared with the original commissioning data.
Assessment of control effectiveness. The examiner checks whether the system is actually capturing the contaminant during normal work, often using smoke tests or a dust lamp, and observes how operators use it.
The commissioning report matters here. It records how the system performed when it was installed and is the baseline every later test is measured against. If you do not have one, the first thorough examination will need to establish a new baseline.
The result is a written report stating whether each part of the system is working effectively, with any defects and the actions needed to correct them.
Who is competent to test LEV?
COSHH requires the thorough examination and test to be carried out by a competent person, but there is no statutory accreditation or licence for LEV testers. Competence means having the training, knowledge and experience to examine the specific type of system and interpret the results.
In practice, the British Occupational Hygiene Society (BOHS) qualification P601, covering the thorough examination and testing of LEV systems, is the most widely recognised benchmark. When choosing a provider, ask to see their qualifications and an example report.
Independence is worth considering too. A tester who also designs, installs or sells extraction equipment may have a commercial interest in recommending upgrades. An independent examiner has no reason to recommend anything beyond what your system genuinely needs.
What records do you need to keep?
COSHH Regulation 9 requires a record of each thorough examination and test, including any repairs carried out as a result, to be kept for at least five years. In practice, a well-run LEV file includes:
The commissioning report and user manual for each system
Every thorough examination and test report
An LEV logbook recording routine user checks between examinations
Records of repairs, modifications and filter changes
Training records for the people who use and check the LEV
Routine checks between examinations are an important part of the picture. HSG258 recommends that users carry out simple, regular checks, such as reading airflow indicators and looking for visible damage, so that problems are picked up long before the next formal test. If an HSE inspector or your insurer asks how you know your LEV is working, these records are your answer.
What happens if your LEV fails its test?
A failed examination means the system is not providing adequate control, so workers may be exposed. COSHH requires employers to make sure control measures are maintained in efficient working order and good repair, so defects must be put right promptly.
While repairs are arranged, you may need interim measures, such as restricting use of the affected process, increasing supervision or providing suitable RPE. Once repairs are complete, the system should be retested to confirm it is performing as intended.
It is also worth asking why it failed. A system that has drifted out of performance since its last test often points to gaps in routine checks or maintenance, rather than a one-off fault.
Does the same apply in Northern Ireland and Ireland?
The COSHH Regulations 2002 apply in England, Scotland and Wales. Northern Ireland has its own COSHH Regulations, which take the same approach to LEV examination.
In the Republic of Ireland, COSHH does not apply. Employers' duties come from the Safety, Health and Welfare at Work (Chemical Agents) Regulations 2001 to 2021. The Health and Safety Authority's LEV guidance recommends that every LEV system is thoroughly examined at least every 14 months, with routine monitoring in between. It also advises that where static pressure readings move more than 20% above or below the baseline, remedial action is needed.
The interval is the same, but in Ireland it comes from HSA guidance rather than a fixed statutory schedule.
Getting Your Next LEV Examination Booked In Time
Most missed LEV tests are a scheduling problem rather than a deliberate choice. A simple check now will keep you compliant:
Find the date of the last thorough examination for every LEV system on site, including mobile units and fume cupboards.
Add 14 months, or less if any system falls under Schedule 4 or your COSHH assessment calls for it.
Book the next examination well before that date, allowing time for any repairs and a retest.
Check your LEV logbook is being filled in between tests.
ISHEM provides independent health and safety consultancy, including LEV thorough examination and testing, COSHH assessments and workplace exposure monitoring. Our consultants are members of the British Occupational Hygiene Society, the Institution of Occupational Safety and Health and the International Institute of Risk and Safety Management. Where sampling is required, analysis is carried out by laboratories accredited to ISO/IEC 17025.
We have no commercial relationships with extraction suppliers or installers, so our recommendations are based only on what your system needs. If you are unsure how LEV fits alongside general ventilation, our guide to indoor air quality at work explains the difference, and our indoor air quality and compliance monitoring services can help keep both on track.
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