What Is COSHH LEV Testing and Why Does Every Employer Need to Know About It?

Engineer checking an extraction hood with a handheld probe

COSHH LEV testing is the thorough examination and test of local exhaust ventilation used to control exposure to hazardous substances. It assesses the extraction system’s performance and identifies defects or limitations that need attention.

How LEV fits into COSHH

Employers must assess hazardous-substance risks and prevent or adequately control exposure. Where LEV forms part of those controls, it needs to be suitable, used correctly and maintained. A test report supports that work; it is not a guarantee that every workplace exposure is controlled in every circumstance.

Examination intervals and records

Most systems require thorough examination and testing at intervals of no more than 14 months. Some specified processes require shorter intervals. The equipment’s condition and operating circumstances may also justify a shorter schedule. Confirm the appropriate interval rather than assuming one applies to every industry.

Keep examination records for at least five years. Also retain commissioning information and operating instructions so future assessments have a useful performance benchmark.

What the examiner considers

  • The process, contaminants and how the extraction is used.

  • Hoods, ductwork, filters, fans and visible defects.

  • Relevant performance information and previous findings.

  • Observations and measurements appropriate to the system.

  • Whether further investigation or remedial work is needed.

The examiner must be competent for the work. Training and qualifications are useful evidence alongside knowledge, practical skills and relevant experience.

What to do after the examination

Read the report and clarify any limitations or recommended actions. Address defects promptly and assess whether affected work can continue safely with the controls available. Keep a record of repairs and agree how restored performance will be checked.

Continue user checks and maintenance between examinations. A service visit and a thorough examination have different purposes; neither should be assumed to replace the other.

Arrange practical support

Premier LEV provides LEV testing and servicing and remedial support across the UK. Send your system details and latest report so we can discuss the work needed.

Further reading: HSE’s guidance for employers and LEV examiners.

Questions to ask before booking

What information should I send?

Provide your site location, system references, process details and previous examination report. Tell us about access restrictions and any changes since the last test.

Does a test include repairs?

Agree the scope before booking. Examination identifies findings; repairs and any subsequent performance checks need to be separately defined.

What if commissioning information is missing?

Tell the examiner in advance. Establishing a suitable performance benchmark may require additional investigation, and limitations should be explained in the report.

COSHH LEV testing is the process of examining and testing Local Exhaust Ventilation (LEV) systems to ensure they effectively control hazardous substances such as dust, fumes, and vapours in the workplace.
Yes, under COSHH regulations, employers must ensure LEV systems are thoroughly examined and tested at least every 14 months to remain legally compliant and protect employee health.
COSHH LEV testing helps prevent exposure to harmful airborne contaminants, reduces health risks, ensures legal compliance, and avoids fines or business disruptions.
A qualified engineer inspects the system, measures airflow performance, checks filters and ducting, and provides a detailed report highlighting any issues and recommendations.
Employers should schedule regular testing, maintain records, carry out routine maintenance, and work with certified LEV professionals to ensure systems remain effective and compliant.
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Is Your LEV System Legally Compliant? What UK Employers Must Know in 2026