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LEV testing - the overview
If LEV, COSHH, TExT and HSG258 are a blur of initials, start here. This is the plain-English overview of what LEV is, what the law asks of you, and how the pieces fit together.
The short answer
LEV - local exhaust ventilation - is the extraction that captures a hazardous substance at source before anyone breathes it. Under COSHH you must control exposure, keep the LEV that does it in efficient working order, have it thoroughly examined and tested at least every 14 months, and keep the records for at least five years. That, in a sentence, is what COSHH requires. The rest is detail.
What LEV is
LEV stands for local exhaust ventilation - an engineering system that draws contaminated air away at the point it is produced, before it reaches the people working nearby. It covers a wide range of kit: kitchen and process canopies, welding fume arms, spray booths, dust hoods on woodworking machines, on-tool extraction, downdraught benches and fume cupboards. What they share is a job: capture the fume, dust, mist or vapour at source.
The reason it exists is health. The substances LEV controls - weld fume, wood and flour dust, solvent vapour, oil mist and many others - cause occupational illness if breathed in over time. LEV is the control that stops that happening, which is why the law takes its condition seriously.
What COSHH asks
The Control of Substances Hazardous to Health Regulations 2002 - COSHH - set the duties. Regulation 7 requires you to prevent or adequately control exposure to hazardous substances. When you meet that by installing LEV, Regulation 9 requires you to keep that LEV in efficient working order and good repair, and to have it thoroughly examined and tested at suitable intervals - at least every 14 months for most processes.
Alongside the test, COSHH requires records: the report of each thorough examination and test, and the record of any repairs, kept for at least five years. So the duty is a loop - control the substance, maintain the control, test that it works, and keep the evidence.
What the test is
The statutory test is a thorough examination and test - often shortened to TExT - carried out to the HSE guidance HSG258. It has three stages: a visual examination of the system's condition; measurement of its technical performance, such as face velocity and capture at each hood; and an assessment of whether it is genuinely controlling exposure for the people using it.
The result is a report that says, with figures, whether each part of the system is doing its job, plus any remedial actions. That report is the evidence the whole exercise produces - what an inspector will ask to see, and what your own risk assessment relies on.
How often, and who
Most LEV must be examined and tested at least every 14 months. That is a legal maximum, not a target - some higher-risk processes named in COSHH Schedule 4 must be tested more often, and any system should be tested sooner where risk or wear demands it. The odd figure of 14 months lets the test date rotate through the year rather than always falling in the same busy period.
The duty sits with the employer, and it cannot be delegated away. You can outsource the testing work, but the responsibility for acting on the report, closing out defects, keeping the records and maintaining the system between tests stays with you.
Putting it together
So the whole picture is straightforward once the initials are unpacked: LEV captures the hazard, COSHH requires you to keep it working and prove it, the thorough examination and test on the 14-month cycle is how you prove it, and the records are how you show it over time. Meet those and the duty is covered; miss them and you are exposed both legally and in terms of your workers' health.
From here, the related guides go deeper on the parts that matter most - whether it is a legal requirement, what it costs, the duties employers underestimate, and how often it must be done - so you can pick up whichever question is yours.
Who needs it
LEV is far more widespread than many employers realise, because the duty follows the hazard rather than the industry. Welding and fabrication shops capture weld fume, now treated as a carcinogen even on mild steel. Joinery and woodworking capture wood dust; bakeries capture flour dust; vehicle bodyshops and spray booths control paint mist and isocyanates. Engineering shops handle oil mist, foundries handle metal fume, and laboratories, pharmaceutical sites, dental practices and nail bars all rely on extraction of one kind or another.
If a process at your site gives off dust, fume, mist, vapour or gas that could harm health, and something extracts it at source, that something is LEV and the COSHH duties apply. The variety of kit is wide, but the underlying question is always the same: is the extraction actually capturing the hazard, and can you prove it.
Questions
Local exhaust ventilation - an engineering system that captures a hazardous substance such as fume, dust, mist or vapour at source, before it reaches the people working nearby. Canopies, fume arms, spray booths, dust hoods and fume cupboards are all LEV.
To control exposure to hazardous substances, keep the LEV that does it in efficient working order, have it thoroughly examined and tested at least every 14 months, and keep the records for at least five years.
A three-stage assessment to HSG258: a visual examination of the system's condition, measurement of technical performance such as face velocity and capture, and a judgement on whether exposure is being controlled - resulting in a report with figures and any remedial actions.
At least every 14 months for most processes - a legal maximum, not a target. Some higher-risk processes must be tested more often, and any system sooner where risk or wear demands it.
The employer's. You can outsource the testing work but not the duty to act on the report, keep records, and maintain the system between tests.
Here, then the related guides on whether it is a legal requirement, what it costs, and the duties employers underestimate - each goes deeper on one question.
We test to COSHH and HSG258 and help you keep the cycle, records and actions straight - so the duty is genuinely met.
