Local extract ventilation, more commonly referred to as Local Exhaust Ventilation (LEV), captures airborne contaminants close to the point where a process creates them. In manufacturing, welding, woodworking and other workplaces that generate dust, fumes, vapours or mist, LEV can form an important part of the controls used to protect employee health.
For most LEV systems, the maximum interval between a thorough examination and test is 14 months. Some processes listed in Schedule 4 of the Control of Substances Hazardous to Health Regulations 2002 require shorter intervals, and employers may need more frequent testing if wear and tear could reduce performance sooner. Employers should continue routine checks and maintenance between formal examinations.
Why does LEV need testing every 14 months?
LEV can continue running even when its ability to capture contaminants has changed. A fan may still operate while a blocked filter, damaged duct, worn component or poorly positioned hood reduces control at the source. Regular examination gives employers evidence of how the system performs against its intended standard.
employers should arrange a thorough examination and test at least every 14 months for most systems. The examiner should assess the complete LEV system and judge if it continues to contribute to adequate control of exposure. Employers must keep records of these examinations and tests for at least five years.
Some activities require shorter statutory intervals. Schedule 4 of COSHH sets one-month intervals for certain blasting and jute-manufacturing processes, and six-month intervals for specified grinding, abrading, polishing and non-ferrous metal casting processes. A competent person can also recommend a shorter interval where the condition or use of a system means performance may deteriorate before the next 14-month date.
What should employers check between formal LEV tests?
The formal examination forms one part of LEV management. Operators, supervisors and maintenance teams should carry out suitable routine checks so faults do not remain unnoticed between test dates.
HSG258 gives daily, weekly and monthly checks as examples. The right schedule depends on the system and should reflect the user manual, commissioning information and LEV logbook. Teams may need to check airflow indicators, hood condition, filters, hoses, ductwork, connections and other components that affect performance.
These checks also give the business useful maintenance information. Repeated filter loading or recurring damage can show where maintenance frequencies need review. Operators can report changes in extraction performance early, which gives engineering teams more time to investigate before control deteriorates further.
What should you review before an LEV test is due?
Start with the previous examination report. Confirm that your team completed any actions and check the maintenance history for repairs, filter changes, faults or recurring defects. Then review changes to the process since the last examination.
A new machine, different material or revised workstation layout can change how contaminants enter the air. Moving a source further from a hood can also affect capture. The same applies if operators use a movable hood differently from the method assumed when the system was commissioned.
Original commissioning information gives the examiner a useful reference point. This may include the intended hood position, airflow, pressure data and other performance information. HSE advises examiners to test LEV against the commissioning report or an equivalent performance standard where it is available.
If you cannot locate the original information, tell the examiner before the visit. A competent person can still assess the system, but the report may need to explain how they established the performance standard and any limitations created by missing records.
Plan your next LEV examination before the due date
If your 14-month test date is approaching, our LEV inspection and testing service can assess current system performance and identify defects that need attention. Our occupational hygienists monitor and analyse performance data, carry out qualitative evaluation of contaminant control and compare test results with the original LEV specification and relevant HSG258 performance criteria.
Planning the examination before the due date gives health and safety, engineering and maintenance teams time to gather records, arrange access and resolve any known issues. It also helps you schedule follow-up work around production and maintenance requirements.
What happens during an LEV thorough examination and test?
A competent examiner carries out a detailed and systematic assessment of the system. The work combines a physical examination with measurements and professional judgement about the way the LEV controls the contaminant.
The exact test depends on the system. The examiner may assess hoods and extraction points, measure airflow or pressure, inspect ductwork and air-cleaning equipment, and use qualitative methods to see how effectively the hood captures the contaminant. The examiner then compares the results with the original specification, commissioning information or another suitable performance standard.
The report should give the employer a clear record of the findings and identify defects or actions that need attention. This allows the responsible team to prioritise work and confirm who will manage each action.
LEV testing assesses the engineering control itself. If you also need evidence of employee exposure to dust, fumes, gases or vapours during real tasks, occupational exposure monitoring can provide additional information. The two assessments answer different questions and can work together where the risk assessment identifies a need.
How should businesses use the LEV report?
The report should support decisions after the site visit. Assign responsibility for each action, set completion dates and address defects that reduce control promptly. After repairs or adjustments, carry out suitable checks to confirm that the system performs as required.
The findings can also support future maintenance planning. If the same fault appears repeatedly, the team can review maintenance intervals, operator practices or the design of the control. This can help prevent repeat defects and gives managers clearer information for budgets, shutdown planning and equipment decisions.
Changes to the process or substances may also trigger a review of the COSHH risk assessment. If the same operation creates significant sound exposure, a separate noise assessment may also be appropriate. Each assessment should address its own hazard so managers can base decisions on the right evidence.
Keep LEV performance under regular review
The 14-month examination date should sit within a wider maintenance schedule. Routine checks help your team identify day-to-day issues, while the thorough examination provides a periodic technical assessment of current performance. Keeping the LEV logbook, maintenance history and examination reports together also makes it easier to see recurring faults and plan future work.
We provide LEV inspection and testing alongside occupational exposure monitoring and COSHH risk assessments. If you need to confirm current performance, review findings from a previous report or plan the next examination, contact our team to discuss your LEV system and the support you need.