Local Exhaust Ventilation (LEV) systems remain one of the most effective engineering controls available for reducing employee exposure to hazardous substances in the workplace.
However, many LEV systems fail to achieve effective control not because the equipment itself is inadequate, but because key stages in the process — such as risk assessment, specification, design or maintenance — have been overlooked.
For duty holders, effective LEV management should be viewed as a complete lifecycle process rather than a single compliance exercise.
Our LEV Route To Control® provides a structured approach to help organisations achieve effective, sustainable and compliant exposure control.
Why LEV Management Matters
Under the Control of Substances Hazardous to Health (COSHH) Regulations, employers have a duty to assess and control employee exposure to hazardous substances.
These substances may include:
Poorly performing LEV systems can lead to:
An LEV system should not simply “exist” — it must be suitable, effective and maintained throughout its operational life.
The LEV Route To Control®
Step One – Risk Assessment
Every successful LEV system starts with a suitable and competent risk assessment.
This stage identifies:
Errors at this stage can result in poorly targeted control measures and systems that fail to protect operators effectively.
A competent assessment should also consider:
The risk assessment forms the foundation for every stage that follows.
Step Two – Specification
A clear and practical specification is critical to achieving effective LEV performance.
The specification stage defines exactly what the LEV system is required to do and ensures that operational, engineering and compliance requirements are aligned from the outset.
Developing an effective specification often requires collaboration between:
A suitable specification should consider:
Poor specifications are one of the most common causes of underperforming LEV systems. A system may appear operational while still failing to adequately control exposure.
Step Three – Design
LEV design is a specialist discipline and has a direct impact on system effectiveness.
Good LEV design focuses on capturing or containing hazardous contaminants before they enter the operator’s breathing zone.
Effective design requires an understanding of:
Hood design and placement are particularly important. The greater the degree of enclosure around the process, the more likely the system is to achieve effective control.
Poor design can lead to:
Step Four – Installation
Even well-designed LEV systems can fail if installation standards are poor.
Installation should ensure the system has been assembled correctly, all components are suitable and airflow paths are unobstructed.
For more complex systems, installation may involve:
Attention to detail during installation helps avoid performance issues later during commissioning and operation.
Step Five – Commissioning
Commissioning confirms that the LEV system is capable of achieving adequate control under normal operating conditions.
This is one of the most important stages in the LEV lifecycle, yet it is often underestimated.
A robust commissioning process should include:
Where existing LEV systems have limited documentation, performance testing becomes particularly important in establishing whether adequate control is being achieved.
Commissioning should provide duty holders with confidence that the system performs as intended in practice — not just in theory.
Step Six – Service and Maintenance
LEV systems require ongoing maintenance to remain effective.
Over time, filters block, ductwork degrades, airflow changes and mechanical components wear. Without planned maintenance, even a well-designed system can gradually lose effectiveness.
A maintenance programme should include:
Maintenance records should be retained within the LEV logbook to support compliance and demonstrate ongoing system management.
Well-maintained systems are more reliable, more energy efficient and more likely to continue providing effective exposure control.
Step Seven – Routine Thorough Examination and Test (TExT)
Routine Thorough Examination and Test (TExT) is essential for verifying that the LEV system continues to achieve adequate control during normal operation.
Under COSHH Regulation 9, LEV systems should be thoroughly examined and tested at suitable intervals, typically at least every 14 months unless more frequent examination is required.
However, effective TExT should go beyond basic airflow readings.
Our LEV Control Review process uses a four-stage approach:
This process helps duty holders understand:
Regular review helps organisations maintain compliance while supporting long-term employee health protection.
Effective LEV Requires a Lifecycle Approach
Effective LEV management is not achieved through testing alone.
Duty holders should view LEV as a continuous lifecycle process involving:
When these stages work together, organisations are more likely to achieve:
A well-managed LEV system is not only a compliance requirement — it is an important investment in workplace health, operational resilience and long-term business performance.
If you would like support with LEV risk assessment, commissioning, TExT or lifecycle management, speak to our LEV specialists.
