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Planning ahead

How often is LEV testing required?

Local exhaust ventilation (LEV) must be thoroughly examined and tested at least once every 14 months. Four processes listed in COSHH Schedule 4 have a shorter limit of one or six months. This guide sets out the LEV testing frequency for each case, when to test sooner, and what to keep.

First published 22 September 2026. Checked 6 November 2026.

A fixed metal hood and a flexible extraction arm sit above workbenches in an empty workshop.
longest gap between tests for most LEV
14 months
months, the limits for four Schedule 4 processes
1 or 6
booking cycle that keeps two months in hand
12 months
minimum time to keep each test record
5 years

LEV testing frequency at a glance

The duty sits with the employer. Regulation 9(2)(a) of the Control of Substances Hazardous to Health Regulations 2002 (COSHH) sets the longest gap allowed between one thorough examination and test of LEV plant and the next. Northern Ireland has its own COSHH Regulations 2003, and HSENI gives the same 14-month limit.

The six limits side by side, in months
  1. Most LEV plant 14 months
  2. On-tool extraction unit 14 months
  3. Dry grinding of metal 6 months
  4. Non-ferrous castings 6 months
  5. Blasting metal castings 1 month
  6. Jute cloth manufacture 1 month

The table below gives the full wording and the source for each figure.

Longest gap between LEV tests
What is being testedLongest gapWhere it comes from
Most LEV plant14 monthsCOSHH regulation 9(2)(a)
Metal casting cleaning by blasting1 monthCOSHH Schedule 4
Jute cloth manufacture1 monthCOSHH Schedule 4
Dry grinding, abrading or polishing of metal (not gold, platinum or iridium) by mechanical power, in any room for more than 12 hours a week6 monthsCOSHH Schedule 4
Dust or fume from making non-ferrous metal castings6 monthsCOSHH Schedule 4
The extraction unit of on-tool extraction14 monthsHSE LEV frequently asked questions

What the law lists, and what it does not

Schedule 4 names four processes. It does not name wood dust, welding fume, spray booths, isocyanates, metalworking fluid mist or chromium plating. HSG258, the HSE guide to LEV, does not give any of them a fixed shorter interval either. Its Table 18 repeats the four Schedule 4 processes and nothing more.

You may read that these processes legally need a test every six months, or every month. Neither COSHH nor HSG258 says so. If a process is not in Schedule 4, the legal limit is the 14 months in regulation 9.

That is the legal ceiling, not advice to test as rarely as you can. HSG258 paragraph 329 says tests should be more frequent where wear and tear is liable to reduce effectiveness between tests. Paragraph 330 adds that the Schedule 4 intervals may help suggest reduced intervals for similar processes. Its example is abrasive blasting of articles other than castings, at one month. Treat that as guidance on judgement, not as a rule.

HSG258 appendix 1 says the frequency should reflect the type of control, how serious the risk is if it fails and how likely it is to fail or deteriorate.

How the 14 months works

The 14 months are a ceiling between tests, counted from the date of the last one. The report should show the date, and HSG258 suggests a hood label with a "next test" line so operators can see it too.

There is no rule that the test must be yearly. Booking every 12 months leaves two months in hand before the 14-month limit. That is advice, not a legal requirement.

The LevHQ LEV test due date calculator works out the date for a system on the general 14-month limit. If a Schedule 4 process applies, or your report sets a shorter gap, use that instead.

Last test Each box is one month counted from the date of the last test. The orange box is the latest month for the next one.

Most systems: the next test is due no later than 14 months after the last one. A test completed on 9 March 2026 must be followed by another no later than 9 May 2027.

6 months: the two Schedule 4 processes in the 6-month rows of the table.

1 month: the two Schedule 4 processes in the 1-month rows of the table.

When to test sooner than the maximum

Some events call for an earlier look, even though the 14 months have not run out.

Tick any that apply to your system.

On-tool extraction and hired equipment

On-tool extraction counts as LEV. HSE says the extraction unit needs a thorough examination and test at least every 14 months, and more often if wear could cut its effectiveness early. The hoods and hoses are not part of that test. They need regular visual checks and repair or replacement if damaged.

If you hire a unit, the hire company owns the duty to have it tested. Look at the test expiry date, especially on a long hire. HSE says you are responsible for not using the unit once its test has expired.

Routine checks are a separate job

The 14-month test does not cover the weeks in between. HSG258 paragraph 324 describes daily, weekly and monthly checks that keep the system working. A trained employee can do them, and the logbook sets how often and what to look at.

Examples in the logbook section include hoods, airflow indicators, damage and blockages, duct wear, filter pressure, fan noise and whether operators use the hood as intended. Put the results in the logbook and fix defects when you find them rather than waiting for the next visit.

Useful as they are, routine checks never stand in for an examination by a competent person. The guide to what happens during an LEV test covers what that visit involves.

What to keep, and for how long

Regulation 9(4) requires a suitable record of each examination and test, and of repairs made as a result. The record, or a suitable summary, must stay available for at least five years from the date it was made. HSG258 paragraph 350 adds that a copy should be available at the workplace with the LEV.

HSE also says to keep information on the installed system, such as the commissioning report, for the life of the equipment. It gives the next examiner something to measure against. Our guide to understanding your LEV report lists what a record normally holds.

If the test is overdue

What to do when the test date has passed

  1. Book a competent examiner

    Regulation 9(2) sets a maximum gap, so once 14 months have passed the test is overdue. Book a competent examiner now and keep the booking confirmation.

  2. Read an overdue date correctly

    An overdue date does not show the LEV has failed. It does mean nothing current shows it still controls exposure.

  3. Act on the new report

    When the new report arrives, act on its list of actions and keep it with the earlier ones.

Where to go next

This guide covers timing. Each of these takes one question further.

Related LevHQ guides and the due date tool
QuestionWhere to look
When my next test falls dueLEV test due date calculator
The basics of the testWhat is LEV testing?
Which regulations applyLEV testing regulations
What the examiner does on siteWhat happens during an LEV test?
Making sense of the written reportYour LEV test report and certificate explained
Typical pricesLEV testing cost
Picking an examinerHow to choose an LEV testing company
Finding a company in your areaLEV testing companies in the UK

Check what you know

4 quick questions from this guide. Nothing you choose is saved or sent.

  1. What is the longest gap between thorough examinations and tests for most LEV?
    Show the answer

    14 months. COSHH regulation 9(2)(a) says at least once every 14 months. Booking every 12 months only leaves two months in hand.

  2. Does COSHH Schedule 4 give wood dust extraction a shorter limit than 14 months?
    Show the answer

    No, the 14-month limit applies. Schedule 4 names four processes and wood dust is not one of them. HSG258 paragraph 329 still says to test more often where wear is likely to reduce effectiveness.

  3. A test is completed on 9 March 2026. What is the latest date for the next one on the 14-month limit?
    Show the answer

    9 May 2027. Regulation 9(2)(a) sets at least once every 14 months, so a test on 9 March 2026 needs the next one by 9 May 2027. A Schedule 4 process or a shorter interval in your report brings that date forward.

  4. How long must the record of each examination and test stay available?
    Show the answer

    At least five years from the date it was made. Regulation 9(4) sets at least five years from the date the record was made.

Questions duty holders ask

How often should LEV be tested?

At least once every 14 months. That is the general legal limit in COSHH regulation 9(2)(a). Four processes in Schedule 4 have shorter limits of one or six months. HSG258 also says to test more often where wear is likely to reduce effectiveness between tests.

Does wood dust or welding fume extraction need testing every six months?

Not by law. COSHH Schedule 4 does not list wood dust, welding fume, spray booths or metalworking fluid mist, so the 14-month limit applies. HSG258 paragraph 329 still says to test more often where wear is likely to reduce effectiveness between tests.

Why is LEV tested every 14 months and not every year?

Regulation 9(2)(a) sets 14 months as the longest gap, not a yearly cycle. Booking every 12 months leaves two months in hand before that limit. Where Schedule 4 applies or the report sets a shorter gap, that date comes first.

How often does LEV need to be checked between tests?

HSG258 describes daily, weekly and monthly checks, with the frequency and content set in the system logbook. A trained employee can do them. They help catch faults early, but they do not replace the thorough examination and test by a competent person.

Is LEV testing needed after changes to the system?

HSG258 paragraph 274 says all systems need commissioning, and recommissioning, when the process, workplace layout or source equipment changes, or a branch is modified or added. Do it when the change is made, not at the next scheduled test.

Does on-tool extraction need an LEV test?

Yes. HSE says the extraction unit needs a thorough examination and test at least every 14 months. The hood and hoses are checked visually and kept in repair. If you hire the unit, check its test has not expired before you use it.

What happens if my LEV test is overdue?

Book a competent examiner straight away. Regulation 9(2) sets a maximum gap, so an overdue test means the duty has not been met. Keep a record of the booking.

Is your next test due?

Put in the date of the last test and get the deadline, with a reminder if you want one.

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Sources

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