Home > Blog > How Often Should LEV Be Tested? The 14-Month Rule Explained
The short answer: at least every 14 months. But there is more to it than that.
What the Law Says
COSHH Regulation 9 requires that any local exhaust ventilation system used to control exposure to hazardous substances must undergo thorough examination and testing by a competent person at suitable intervals.
For most LEV systems, “suitable intervals” means no longer than 14 months. This is not a target or a guideline. It is a legal maximum.
When More Frequent Testing Is Required
Some processes are higher risk and require shorter intervals. COSHH Schedule 4 specifies:
- Every 6 months: Processes involving certain lead compounds, asbestos (some circumstances)
- Monthly: Some highly hazardous operations
Your risk assessment may also determine that more frequent testing is appropriate based on the substances controlled and the consequences of failure.
The 14-Month Clock
The interval is measured from the date of the last thorough examination. Not from the date you received the report, not from the date you actioned the recommendations, but from the examination date itself.
If your last examination was on 1 January, the next must be completed by 1 March the following year (14 months later). Miss that date and you are non-compliant, regardless of whether the system is actually working.
What Counts as a Thorough Examination?
A thorough examination is NOT:
- A service visit
- A filter change
- A quick visual check
- A maintenance engineer saying “looks fine”
It IS:
- A structured assessment by a competent person (typically BOHS P601 qualified)
- Measured airflow and capture data at each extraction point
- Comparison against design/commissioning performance
- A written report with pass/fail outcomes
- Documentation of defects and remedial actions
Don’t Let the Clock Run Out
We track due dates for all our clients and schedule examinations in advance. If you are unsure when your LEV was last tested, or if you have inherited a system with no records, contact us. We can assess what you have and establish a compliant testing schedule. See our LEV thorough examination and testing service.
Not Sure When Your LEV Was Last Tested?
We can assess your system and get you back on a compliant schedule.
