LEV commissioning and LEV testing both assess local exhaust ventilation performance, but they serve different purposes. Commissioning establishes how an LEV system should perform when it is brought into use, while Thorough Examination and Testing (TExT) assesses its ongoing condition and performance.
Understanding LEV commissioning vs testing is particularly important when a new system is installed, an existing system is modified or an employer is reviewing whether its LEV records provide suitable performance benchmarks.
LEV commissioning takes place when an LEV system is being brought into use. It establishes whether the system performs according to its intended design and whether it provides adequate control under the conditions assessed.
The commissioning results also establish important performance benchmarks, such as relevant airflow, pressure and velocity measurements.
A Thorough Examination and Test is a periodic, systematic assessment by a competent person to determine whether an existing LEV system continues to perform as intended and provide adequate control of exposure.
Put simply:
Commissioning establishes the performance benchmark. TExT checks the system against appropriate benchmarks as it continues in service.
Neither should be treated as a substitute for the other.
Commissioning is the process of establishing whether an installed LEV system works as intended before it becomes part of normal workplace control arrangements.
HSENI states that after an LEV system has been installed, it should be commissioned to demonstrate that it is working correctly and capable of providing the intended protection. The commissioning results should then be retained as a benchmark against which future system performance can be assessed.
HSE's LEV commissioning guidance similarly explains that commissioning establishes whether the system is delivering the required control and creates performance standards that can be used for future examinations, maintenance and performance management.
Commissioning is therefore more than simply switching on a new extraction system to see whether the fan runs. It should produce documented performance information that can be used throughout the system's working life.
The exact commissioning process depends on the design, contaminant, process and complexity of the LEV system.
HSE's HSG258 guidance on controlling airborne contaminants at work explains that commissioning establishes whether the LEV delivers its intended technical performance and provides information that can be used as a benchmark for future examinations and tests.
Relevant measurements may include:
Commissioning should also consider whether the LEV is providing effective contaminant control under the conditions in which it will actually be used.
Where operator behaviour affects control, appropriate working practices may also need to be established and recorded.
The commissioning report should record the system, its performance specification, relevant measurements and benchmarks for future checks.
Without suitable commissioning information, it can be harder to determine whether an LEV system's performance has changed.
Consider a future airflow measurement of 12 m/s. On its own, that figure tells you very little.
Whether it represents satisfactory performance depends on factors such as where it was measured, the system design, its intended performance and the original benchmark.
Commissioning establishes the reference information needed to put future measurements into context.
HSG258 states that the commissioning report provides a reference against which regular checks, maintenance and statutory Thorough Examination and Testing can subsequently be compared.
A Thorough Examination and Test, commonly shortened to TExT, is a detailed and systematic examination of an LEV system carried out by a competent person.
Its purpose is to assess whether the LEV continues to perform as intended and provide adequate control of exposure.
This involves more than checking whether the fan is running or taking one airflow measurement.
HSG258 describes TExT as involving sufficient examination and functional testing to provide evidence about the continuing performance of the system.
A competent LEV testing process may therefore include visual and structural examination, function checks, technical performance measurements and assessment of control effectiveness.
For employers in Northern Ireland, most LEV equipment must be thoroughly examined and tested by a competent person at least every 14 months.
However, this should not be interpreted as a universal 14-month interval for every situation.
HSENI's COSHH guidance explains that Schedule 4 of COSHH NI specifies different maximum intervals for LEV used in certain processes. More frequent examination and testing may also be appropriate where wear and tear could cause the effectiveness of a system to deteriorate between tests.
The appropriate testing interval should therefore be established for the particular system and process.
Although some measurements and inspection techniques may overlap, commissioning and TExT answer different questions.
| LEV Commissioning | LEV Thorough Examination and Testing | |
| Main purpose | Establish whether the system performs as intended and create baseline performance information | Assess whether an existing system can continue to perform as intended |
| When carried out | When a system is first brought into use, and potentially following significant changes | Periodically while the system remains in service |
| What it establishes | Initial performance standards and benchmarks | Current condition and performance against appropriate benchmarks |
| Typical information | Design information, airflow, velocity, pressure and other relevant performance data | Condition checks, functional testing and current performance measurements |
| Main output | Commissioning report and baseline information | TExT report, including identified defects/remedial actions where applicable |
| Does it replace the other? | No | No |
Not exactly. Commissioning involves inspection, measurement and testing, which can make the terminology confusing.
However, commissioning establishes that the system performs as intended and creates appropriate benchmarks as it enters normal service. Periodic TExT assesses its continuing condition and performance after it has been in use.
Some measurement techniques may therefore overlap, but the purpose of each process is different.
Changes to an LEV system, process or workplace layout can affect the performance information established during commissioning. If a modification affects the system's design, airflow or control effectiveness, the existing commissioning benchmarks may no longer provide an appropriate reference for future checks and testing.
The extent of reassessment needed will depend on the nature of the change. Where existing performance information is no longer representative, competent assessment may be needed to establish suitable new benchmarks.
Older LEV systems do not always have complete commissioning information available.
That does not mean the system should simply be assumed to perform adequately.
HSG258 recognises the importance of having suitable performance information against which an LEV system can be assessed.
Where commissioning records or design information are missing, a competent LEV specialist may need to establish appropriate performance criteria based on the system, process and control requirements.
The exact approach will depend on the individual installation.
For employers, the important point is not to invent a benchmark simply because the original commissioning report cannot be found.
A TExT is an important part of LEV management, but it should not be treated as a guarantee of overall workplace compliance. As explained in our guide to COSHH Risk Assessments and LEV Compliance, LEV is one control measure within the wider management of hazardous substances.
Effective control can also depend on:
The test report should therefore be used as part of ongoing LEV management rather than simply filed away until the next examination.
Commissioning and testing are most useful when they form part of the same LEV life cycle.
Changes to the system or process may lead to further assessment and, where necessary, the establishment of new performance benchmarks.
LEV records help provide continuity between commissioning, routine operation, maintenance and subsequent testing.
Relevant records may include:
HSENI states that commissioning results should be retained as a benchmark for future performance and that TExT reports should be kept for at least five years.
A well-maintained LEV logbook can also help keep routine checks, maintenance and relevant system information together.
Commissioning establishes whether a newly installed or significantly changed LEV system performs as intended and creates baseline performance information. Periodic Thorough Examination and Testing assesses whether an existing system continues to perform as intended and contributes to adequate exposure control.
HSENI states that once an LEV system has been installed, it should be commissioned to demonstrate that it is working correctly and capable of providing the intended control. The commissioning results should be retained as a benchmark for future performance.
COSHH NI places duties on employers to adequately control exposure to hazardous substances and maintain control measures in efficient working order, good repair and a clean condition. Commissioning helps demonstrate that a newly installed LEV system can provide its intended control and establishes performance information for ongoing management.
Commissioning is not normally carried out according to a fixed recurring interval. It is associated with establishing system performance when an LEV system is brought into service and may also be appropriate following significant modifications that affect its performance or invalidate existing benchmarks.
In Northern Ireland, most LEV equipment must be thoroughly examined and tested by a competent person at least every 14 months. Some processes have shorter maximum intervals, and more frequent testing may be appropriate where the system could deteriorate between examinations.
No. The two processes have different purposes. Commissioning establishes the system's intended performance and baseline information, while TExT assesses its continuing condition and performance during service.
LEV commissioning and testing provide different information at different stages of an LEV system's life. Commissioning establishes how the system should perform, while periodic TExT assesses its continuing condition and performance.
If you are unsure whether an existing system needs commissioning, reassessment or its next Thorough Examination and Test, DevineAir can review the available information and advise on an appropriate next step.
This article provides general information about LEV commissioning and Thorough Examination and Testing. Requirements depend on the system, process, hazardous substances and applicable legislation. Site-specific COSHH assessment and competent LEV advice may be required.
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