Local Exhaust Ventilation (LEV) is critical to ensuring the containment and control of dusts, fumes, vapours, mists, and other hazardous materials that may be released into the workplace air. Whatever your industry – from manufacturing, engineering, and laboratories to food production companies – an efficient LEV system is necessary to protect staff and comply with relevant health and safety laws.
But one thing that often confuses is the distinction between LEV maintenance and LEV testing. The mistake many firms make is believing that the two activities are synonymous, or that by doing one, they no longer have to do the other. But this is far from the truth because each has its own distinct importance.
Proper maintenance will minimise unexpected failures, while testing will ensure the system's efficiency in controlling dangerous substances. Ignoring either one will lead to poor performance, increased risk of employee contamination and exposure, costly downtime, and even non-compliance with COSHH regulations.
Maintenance of LEVs ensures your extraction system works effectively by servicing, inspecting, repairing, and replacing worn parts. Testing of LEVs (Thorough Examination and Test) is an official process that checks whether the system continues to effectively control hazardous substances in the air in accordance with COSHH regulations. Most workplaces will require both.
| LEV Maintenance | LEV Testing |
| Routine servicing and repairs | Formal Thorough Examination and Test (TExT) |
| Prevents breakdowns | Verifies system performance |
| Replaces worn components | Measures airflow and extraction effectiveness |
| Carried out throughout the year | Usually required every 14 months (unless another interval applies) |
| Improves reliability | Demonstrates COSHH compliance |
LEV maintenance focuses on keeping the extraction system in good working condition. Like any mechanical equipment, extraction systems experience wear over time. Fans, filters, ductwork, belts, motors, and extraction arms can all deteriorate through regular use.
Routine maintenance may include:
The aim is to prevent problems before they affect system performance.
Without maintenance, even a well-designed LEV system can gradually lose efficiency, allowing contaminants to escape into the workplace.
LEV testing, often called a Thorough Examination and Test (TExT), is much more than a routine inspection.
It is a detailed assessment that determines whether the system is effectively controlling hazardous substances at source. The process typically includes visual inspections, airflow measurements, performance checks, and comparison against the original design specification, where available.
The Control of Substances Hazardous to Health (COSHH) Regulations stipulate that employers must carry out thorough testing and examination of LEV systems at appropriate intervals. In most instances, this would be at least once every 14 months.
Many businesses invest in regular servicing and assume their legal obligations are covered.
Unfortunately, this is not the case.
Maintenance helps keep equipment running, but it does not formally demonstrate that contaminants are being effectively captured and controlled.
For example, a fan may still operate perfectly even if airflow has been reduced due to partially blocked ductwork. Similarly, worn extraction hoods may continue functioning but fail to capture airborne contaminants efficiently.
Without testing, these issues may remain unnoticed.
The opposite is also true.
Testing identifies whether the system performs correctly at the time of inspection, but it does not prevent failures between examinations.
A system tested today may develop problems several months later because of:
Routine maintenance reduces the likelihood that these issues will develop before the next scheduled test.
The most effective LEV management programmes combine both activities.
Maintenance keeps equipment operating efficiently throughout the year.
Testing confirms the system continues to provide adequate control of hazardous substances.
Together, they help businesses:
LEV systems are used across numerous industries, including:
Where airborne contaminants are generated, maintaining effective extraction should form part of an ongoing health and safety strategy.
The design and uses of different LEV systems differ; it is important to select a capable service provider. The competent expert will be able to conduct comprehensive evaluations, identify any issues, offer practical recommendations, and ensure that the tests are carried out in accordance with COSHH standards.
When choosing a service provider for LEV systems, one should consider the provider's industry experience, knowledge of regulations, ability to write clear reports, and practical suggestions for controlling hazardous substances.
Both LEV maintenance and LEV testing are equally important, but for different reasons. While LEV maintenance ensures that your system functions efficiently, LEV testing proves that your system is still protecting your staff members.
At DevineAir, we provide LEV testing, maintenance, design, consultancy, and training, as well as air quality monitoring, noise assessments, cleanroom testing, hand-arm vibration assessments, and lighting surveys.
If you're unsure whether your LEV system is due for maintenance or testing, our team can help assess your workplace and ensure your control measures remain effective and compliant. Contact us today to learn more about the services we offer.
Employers must ensure LEV systems remain effective. Regular maintenance helps achieve this and supports compliance with COSHH.
Most LEV systems require a Thorough Examination and Test at least every 14 months, although some processes require more frequent examinations. Always refer to COSHH guidance and HSE recommendations.
No. Maintenance keeps the system operating correctly, while testing confirms that it effectively controls hazardous substances.
The report will identify deficiencies and recommend corrective actions. Repairs or maintenance should be completed before the system continues operating, where necessary.
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