LEV Thorough Examination and Test | COSHH LEV 14-Month Test Guide

LEV Thorough Examination And Test Is A Statutory Requirement

Regulation 9 of the Control of Substances Hazardous to Health Regulations places a legal duty on employers. They must ensure the LEV used to control exposure to hazardous substances is examined and tested at suitable intervals. That duty applies for the life of the system. In many cases, the maximum interval is 14 months. This is why TExT is often called the LEV 14-month test.

The 14-month interval is the maximum, not the default. Some systems need testing more often. The risk assessment and COSHH framework set the actual testing frequency. Higher risk requires shorter intervals.

That matters because a Thorough Examination and Test is not simply a scheduled inspection. Its purpose is to determine if the LEV still provides effective control. The examination also checks for changes or defects that could affect performance. If issues are found, the necessary action is determined.

Why LEV TExT Is Separate From Maintenance

Regulation 9 outlines maintenance, examination and test, all of which serve different purposes and need to be managed as separate parts of LEV compliance. Confusing them can leave a serious gap in control.

Maintenance is the ongoing work needed to keep the system in good condition. It includes routine checks, servicing, cleaning and replacement of worn components. Maintenance also covers repairs before faults become bigger problems. Its purpose is to keep the LEV efficient and reduce the risk of deterioration over time.

A Thorough Examination and Test does something different. It provides a formal assessment of whether the LEV is still delivering effective control at the time of examination. That judgement depends on inspection, measurement and comparison with the established basis of control.

This distinction matters because a system can be maintained regularly and still fail to control exposure. This could occur where the process may have changed, the ductwork may have been altered, or hoods may no longer be used as intended. Performance may have deviated from the original benchmark. Routine maintenance may help identify some of these issues, but it does not replace a formal check to determine whether control is still effective in practice.

For employers, the practical point is clear. Maintenance should run year-round as part of normal system care. TExT should be arranged separately as the statutory examination that records whether the LEV still meets the required standard. One supports ongoing upkeep. The other provides formal evidence of current control.

What A TExT Engineer Needs Before The Examination Begins

A Thorough Examination and Test cannot be carried out properly on the basis of a site visit alone. The engineer needs records showing what the system was designed to do, how effective control was established and how the LEV has been managed since. Without that context, the examination becomes far less reliable.

The following documents must be made available before the examination begins:

• Commissioning data. This is the benchmark against which current performance is judged. The engineer must confirm what process was originally assessed, which hazardous substances were controlled and what evidence demonstrated effective control. The implications of missing or inadequate commissioning data are covered later in this article.
• The O&M manual. It is the technical reference for the system as installed. It identifies main components, test points, alarms, indicators, maintenance requirements and any operating limits that affect performance.
• The LEV logbook. This is the system's operating history. It shows routine checks, faults, repairs, maintenance activity and any signs that performance may have declined or that problems remain unresolved.
• Operator training records. These confirm that those using the system have been trained to use it correctly. If working methods have changed or training has lapsed, the engineer needs to know before assessing whether the current basis of control is still valid.
• Risk assessment material. The COSHH Regulation 6 risk assessment for the process, and DSEAR information if applicable, provides the engineer with the hazard context needed. This helps assess whether current control arrangements remain appropriate.

For employers, the practical point is straightforward. A TExT engineer should arrive with sufficient information to examine the system’s purpose and benchmark it. The engineer should not be left to reconstruct that information from scratch on the day. Ensure all listed records are available in advance to enable a thorough and accurate examination.

What A Thorough Examination And Test Actually Involves

A Thorough Examination and Test follows a structured sequence. Each stage has a specific purpose, and together they build a picture of whether the LEV is still performing to the required standard at the time of examination.

• Document familiarisation. Before turning to the physical system, the engineer reviews the provided records, confirming that the commissioning data covers the substance and process currently in use and noting anything in the logbook or system history that warrants closer attention during the physical inspection.
• Initial appraisal. A visual check is conducted before the system is operated, aimed at identifying anything that would make the system unsafe to run or examine. It is also the point at which obvious modifications or significant defects may first become apparent.
• Operational review. Discussion with the user or responsible person, review of maintenance records, and consideration of whether the process, substances or system configuration have changed since commissioning or the last test. Even small changes can affect whether the original basis of control still applies.
• Discharge point check. Confirmation that extracted air is still being discharged safely and that changes to the building or surrounding environment have not created a risk of poor dispersion or recirculation back into the workplace.
• System examination. A thorough inspection of the LEV, with particular attention to components vulnerable to wear, damage or deterioration, including filters, belts, bearings, flexible joints and moveable hoods or arms. Ductwork, dampers, access panels and controls are also examined.
• Operator positioning. When the system includes movable components, such as flexible extraction arms or adjustable hoods, the engineer checks whether they are used within the operating zone for which the system was designed. A mechanically sound hood, even when positioned outside its intended capture zone, may still fail to adequately control exposure.
• Quantitative measurements. Hood pressures, duct pressures, flow rates, air mover pressures and filter pressure drops are taken at the specified test points and compared with the commissioning data. Measurements are taken under worst-case conditions to ensure they reflect the system's actual performance in use.
• Alarm and instrument checks. Alarms, flow indicators, gauges and other instruments are checked against the requirements set out in the system manual. These devices provide operators with real-time indication that the system is functioning within its required parameters. If they are inaccurate or not functioning, the LEV may continue to run without any meaningful warning that control has been lost.

Taken as a whole, TExT is a formal examination of condition, performance and use. It determines whether the LEV still provides effective control in real working conditions. This is more than just checking if the system can be switched on.

Comparing Current Performance Against Commissioning Benchmarks

The measurements taken during a Thorough Examination and Test only become meaningful when compared with a proven baseline. That baseline comes from commissioning. There, the LEV was shown to provide effective control for the process, hazardous substance and working conditions it was designed to manage. The purpose of TExT is not simply to record what the system is doing on the day. It is to determine whether current performance still reflects the standard originally achieved.

That is why the commissioning report matters so much. It should identify the process, hazardous substance, agreed control benchmark and operating data recorded when effective control was proven. Those figures become the later reference point. Flow rates, hood pressures, duct pressures, air mover pressures and filter pressure drops can all be measured during TExT. Their value depends on benchmarking against proven control, not viewing them in isolation.

This comparison identifies deterioration over time. A system may operate and move air, but not control exposure. Filters may have been loaded, dampers may have been altered, or components may have been worn. The process itself may have changed. Comparing current performance with commissioning benchmarks reveals if such deterioration has affected control.

The benchmark itself also needs to be understood properly. It should not be reduced to a single airflow or velocity figure unless that figure genuinely reflects the agreed basis of control. What matters is whether the LEV still provides the required level of protection for the hazard and the way the work is carried out. TExT therefore looks beyond the mere presence of airflow and asks whether the system still meets the standard that matters in practice.

Where no valid commissioning report exists, the examination becomes much weaker. If there is no reliable evidence of what the system achieved when it was first shown to be effective, the TExT engineer has no proper baseline against which to judge current performance. A report that lists pressures and velocities but does not demonstrate effective control leaves the same problem. In those circumstances, the system may need retrospective commissioning before a meaningful comparison can be made.

For duty holders, this is one of the most important practical points in LEV compliance. A valid TExT depends on valid commissioning evidence. The better the original benchmark, the more useful each later examination becomes.

What Happens When LEV Fails TExT

A Thorough Examination and Test does not always confirm that an LEV system is performing as required. Where defects are identified, where performance has deteriorated, or where effective control can no longer be demonstrated, the findings need to be recorded clearly, reported to the responsible person and acted on. The examination only has value if it leads to the right response.

The seriousness of the failure will affect what happens next. Where the engineer finds a significant defect or a condition that makes the system unsafe to operate, the examination may need to be halted before normal testing can continue. In that situation, the system status should be clearly identified, the faults should be recorded as far as they can be determined safely, and the remedial action needed before a further examination takes place should be set out in the report.

In other cases, the system may be capable of examination, but the results may still show that performance has fallen short of the commissioning benchmark or that effective control is no longer being achieved. That failure then needs to be investigated properly. The report should explain the nature of the problem, identify the likely cause where possible and make clear what action is required to restore control.

Where a straightforward fault can be corrected during the visit, and the engineer is competent to carry out that work, it may be reasonable to address the issue immediately. Even then, the defect, the action taken and the outcome should still be recorded. If the problem cannot be resolved at the time, the system’s continued use should be carefully considered. Where satisfactory control is in doubt, a warning label may be needed, and the responsible person must be notified without delay.

That point matters for duty holders. Notification is not the end of the process. Once a failed TExT or serious defect has been identified, the employer needs to ensure the findings are reviewed, prioritised repairs are arranged, and the implications for continued use are addressed. If the LEV cannot currently provide reliable control, exposure risks must still be managed while corrective work is being organised.

The findings should also be reflected in the logbook. A report that identifies faults and recommends action, but is not followed by a clear record of what was done, leaves a gap in the evidence that the system has been properly managed.

Who Is Competent To Carry Out LEV TExT

Competence in LEV Thorough Examination and Test involves more than taking measurements and producing a report. The engineer needs to understand what those readings mean in relation to actual exposure control, system performance and how the LEV is used in practice.

That requires a combination of technical knowledge, relevant experience and familiarity with both LEV engineering and the occupational hygiene context behind the system. The examiner needs to understand how the LEV is configured, how to interpret pressures, flow rates and other test data, and how to judge whether any deviation from the commissioning benchmark affects effective control of the hazardous substance.

Experience also matters. A TExT engineer should be able to demonstrate previous work on systems of a similar type, complexity and risk profile. Testing a simple system is not the same as examining a multi-branch installation serving a higher-risk process, and employers should be able to see evidence that the engineer’s experience is relevant to the task in hand.

Site competence matters as well. LEV examination often involves work at height, access to plant areas and systems serving hazardous processes. Where asbestos risks, specialist access requirements or explosive atmospheres are relevant, the person carrying out the examination needs the training and site safety competence to work safely as well as the technical ability to assess the system properly.

The choice of an engineer should not be treated as a routine procurement decision. A sensible approach is to ask for evidence in advance, such as a methodology document, a sample report from a comparable system and clear confirmation of how the examination will assess effective control against the established benchmark.

Common Weak Practice In LEV Testing

The most serious weaknesses in LEV compliance do not always come from a complete absence of testing. More often, they come from testing that takes place on time but without the records, baseline or technical judgement needed to reach a meaningful conclusion.

• Treating the 14-month interval as the complete compliance strategy. Booking TExT within the permitted period addresses timing only. It does not confirm that the examination was carried out properly, that the engineer had the right information, or that the report provides a reliable judgement on effective control. A system may be tested on time and still be poorly managed.
• Relying on maintenance visits as a substitute for TExT. Regular servicing helps keep the system in working order, but does not replace the formal examination needed to determine whether the LEV still provides effective control against the agreed benchmark. Where that distinction is lost, employers can end up with a maintained system but no proper evidence of current control.
• Missing or weak commissioning evidence. Without a valid commissioning report, the examiner has no proper baseline, and retrospective commissioning may be needed before a meaningful TExT can proceed. A report that records pressures and airflow figures without demonstrating effective control leaves the same gap.
• Poor logbook records. A logbook should show routine checks, maintenance activity, reported defects, repairs and relevant changes over time. One that is incomplete, out of date, or completed retrospectively just before the examination deprives the engineer of the operating history needed to understand the system properly, weakening the evidential value of the test.
• Unreviewed changes to the process or system. Hood arrangements altered, ductwork modified, new substances introduced, or production conditions intensified without anyone reviewing whether the original basis of control still applies. A TExT conducted against outdated commissioning data in those circumstances can produce false reassurance rather than a dependable assessment of current control.
• Appointing an engineer without assessing competence. Selecting a TExT engineer based solely on availability or price, without reviewing qualifications, relevant experience or understanding of exposure control, increases the risk of a report that records measurements but cannot reach a meaningful judgement on whether the LEV is still doing its job.

The value of TExT lies in the quality of the evidence, the relevance of the benchmark, the competence of the examiner and the action taken on the findings. Arranging the visit is only the starting point.

TR40 As The Practical Reference For TExT

Managing LEV Thorough Examination and Test properly requires more than knowing when the next examination is due. Duty holders need to understand what the examination is meant to demonstrate, what records must support it, what competence the engineer needs and what action should follow when defects or loss of control are identified.

That is where TR40 is useful as a practical reference. It places TExT within the wider framework of LEV management, covering procedure, documentation, competency, commissioning benchmarks, maintenance and remedial action. It also helps clarify the relationship between commissioning, maintenance and TExT, where many weaknesses in practice begin.

For employers, appointed responsible persons and engineers involved in LEV management, TR40 provides structured guidance on what good practice looks like across the life of the system.

For those who need the full technical framework behind effective LEV testing and ongoing control, TR40: Local Exhaust Ventilation, A Guide to Good Practice is available from the BESA publications shop at BESA Publications.