Under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), local exhaust ventilation (LEV) systems must be given a thorough examination and test at least once every 14 months. That figure is the maximum interval for most systems. This guide explains where it comes from, why it is 14 months rather than 12, which processes need testing more often, and what a proper LEV test involves.
Where the 14 month interval comes from
COSHH Regulation 9 requires engineering controls, including LEV, to be maintained in efficient working order and in good repair, and that LEV is thoroughly examined and tested at suitable intervals. For most LEV systems, the regulations set that interval at a maximum of 14 months. The odd-looking figure is deliberate. Fourteen months lets an annual test drift slightly from year to year while still landing at roughly the same point in the cycle, so a test booked around the same time each year stays compliant without the date creeping steadily earlier.
Processes that need testing more often
The 14 month interval is a maximum for typical systems, not a universal rule. COSHH lists certain higher-risk processes that require more frequent examination and test. In those cases the interval can be as short as every six months, and for a small number of specified processes, shorter still. If your LEV serves a listed process, the shorter interval applies regardless of the general 14 month figure. Examples of the kinds of work that can attract a shorter interval include:
- Certain grinding, fettling and metal-dressing operations.
- Some processes producing non-ferrous metal castings.
- Blasting carried out in connection with the cleaning of metal castings.
If you are unsure whether your process falls into a shorter-interval category, a competent examiner can confirm it as part of assessing the system.
What a LEV thorough examination and test involves
A LEV test is more than switching the system on. A thorough examination and test typically covers:
- A review of the system against how it was designed to perform, using commissioning data where available.
- Measurement of airflow and, where relevant, capture or face velocities at each hood or extraction point.
- A check that the system draws contaminant away effectively where the work is actually done.
- Examination of ducting, filters, fans and discharge points for wear, blockage, leaks and damage.
- Confirmation that the system controls exposure well enough to help meet workplace exposure limits.
The examination results in a report that records the system's performance, any defects, and the remedial action needed. The record should be kept for at least five years.
Why LEV testing matters
LEV exists to protect people from breathing in dust, fume, mist, vapour and gas that can cause serious, often irreversible, health conditions. A system that looked effective when installed can degrade quietly: filters clog, ducts fill, fans wear, and hoods get moved or damaged. The 14 month examination is how you confirm the protection is still working, and it is a legal duty, not an optional check.
LEV testing across Manchester and the North West
Safe-Lee provides independent LEV thorough examination and testing for employers across the Manchester and North West area. Testing is carried out by Engineer Surveyor Lee Charnock (EngTech MSOE MBES), and reports are typically issued within one to two working days so any remedial work can be planned quickly. See our COSHH LEV inspection service for what a visit covers, or our guide to LEV testing cost for what shapes a quote.
Frequently asked questions
How often does LEV need to be tested?
At least every 14 months for most systems under COSHH. Certain higher-risk processes require more frequent testing, in some cases every six months or shorter.
Why is LEV testing every 14 months and not 12?
The 14 month maximum lets an annual test move slightly within the year while staying compliant, so the date does not creep earlier each year. It is the maximum interval set by COSHH for most systems.
What happens if LEV testing is overdue?
An overdue system cannot be shown to be controlling exposure, which breaches COSHH. It should be examined and tested as soon as possible, and any faults put right.
How long should I keep LEV test reports?
LEV examination and test records should be kept for at least five years and be available for inspection.
Is a LEV test the same as a COSHH assessment?
No. A COSHH assessment evaluates the risk from hazardous substances and the controls needed. The LEV thorough examination and test checks that a specific control, the extraction system, is still working as intended.