When Does Your LEV System Need Thorough Examination and Testing Under HSG258?
- Jun 17
- 7 min read
Updated: Jul 2
If you are responsible for workplace air quality, understanding LEV thorough examination and testing HSG258 requirements is essential. Local exhaust ventilation is often the last line of defence between harmful airborne contaminants and the people breathing them in. If the system is not performing as intended, dust, fume, mist or vapour can escape into the work area.
In simple terms, most LEV systems need a formal thorough examination and test at least every 12 - 14 months. However, good compliance is not just about hitting one calendar date. Changes to the process, poor performance, damage or inadequate maintenance can all mean your system needs attention sooner.
At Pro Vent LEV Ltd, we help businesses understand what to look for and when to act. Based in Jarrow, we provide LEV systems and extraction support, including maintenance and P601 thorough examination and testing services.
Need your LEV system tested, serviced or checked?
Email: enquiry@proventlev.co.uk
Phone: 0191 622 3026
LEV thorough examination and testing HSG258: when is it due?
HSG258 is the Health and Safety Executive guidance commonly used to help employers manage local exhaust ventilation properly. For most systems used to control substances hazardous to health, the legal benchmark is clear: a thorough examination and test is required at least every 12 - 14 months.
That said, the 12 - 14-month rule is the minimum many businesses focus on. It should never be treated as a reason to ignore warning signs between visits.
The minimum interval most employers need to know
If your LEV controls dust, fume, smoke, mist or other airborne contaminants, the system should be examined and tested at least every 12 - 14 months unless a shorter interval applies. The aim is not just to confirm that the fan still runs. The examination should show whether the system is continuing to provide effective control.
This is why a simple service visit is not always enough. Routine maintenance is important, but it is not the same as a formal thorough examination and test.
Why the due date is only part of the picture
An LEV system can drift out of specification gradually. Filters load up. Ductwork can leak. Fans wear. Dampers move. Hoods get knocked out of position. A system may still appear to be working while control performance has dropped below the standard needed for the task.
That is one reason HSG258 places so much emphasis on design performance, testing and records. Without proper checks, it is difficult to know whether the system is genuinely controlling exposure.
When should you act before the next 12 - 14-month examination?
There are several situations where waiting for the scheduled examination is risky. If any of the following apply, your LEV system should be reviewed as soon as possible.
1. The process has changed
If you have changed the material, tool, machine, production rate or method of work, the original LEV settings may no longer match the hazard. A system designed for one type of dust or fume may not capture another in the same way.
Even small changes can matter, especially where heat, particle size, airflow pattern or operator position has changed.
2. The system has been moved, altered or extended
Adding extra branches, replacing components, moving a hood or changing the duct layout can affect airflow across the whole system. What looks like a minor alteration may reduce capture at the point where contaminant is generated.
New or altered LEV should be properly commissioned and its performance established, so future examinations have a reliable benchmark.
3. You can see signs of poor control
Do not wait for the paperwork date if you are noticing obvious warning signs, such as:
visible dust or fume escaping into the room
operators reporting irritation, odour or discomfort
residue building up around the process
unusual noise or vibration from the fan or ductwork
reduced extraction at the hood or work point
frequent filter or blockage issues
These symptoms do not automatically mean the whole system has failed, but they do mean it needs prompt attention.
4. Maintenance has identified a fault
A damaged hood, worn fan, leaking duct, blocked filter or faulty indicator can all affect performance. In many workplaces, the problem is not that no one arranged a test. It is that the system was left running with known faults between tests.
Regular maintenance and a clear defect response plan help prevent small issues becoming compliance problems.
5. There has been a breakdown, incident or long period out of use
If a system has suffered damage, been shut down for a significant period, or been affected by an incident, it is sensible to verify performance before relying on it again. The question is simple: can you be confident it is still controlling contaminants effectively?
What should a thorough examination and test of LEV include?
A proper thorough examination and test is more than a glance at the system. It should combine inspection, measurement and judgement so the employer can see whether the LEV is still fit for purpose.
Visual inspection of the system
This usually includes checking the condition and suitability of key components, such as:
hoods and enclosures
ductwork and access points
air cleaners, filters or separators
fans, drives and controls
discharge arrangements
indicators, alarms or gauges where fitted
The examiner will also consider how the system is being used in practice. A well-designed installation can still underperform if the hood position, work method or housekeeping is poor.
Performance measurements
Testing normally involves taking measurements that help confirm whether the system is performing to the required standard. Depending on the system, that may include airflow, air velocity, pressure readings or other relevant indicators.
The important point is that the results should be compared against meaningful benchmarks, not taken in isolation.
Review of control effectiveness
The central question is whether the LEV is still adequately controlling exposure. That means looking at the task, the contaminant, the condition of the system and the test data together.
A pass is not just about equipment movement. It is about whether the control measure remains effective for the real job being done.
Clear reporting and remedial actions
A proper report should record the findings, identify any defects and explain what corrective action is needed. Employers should retain LEV examination records for the required period, which is commonly at least five years.
If remedial work is identified, it should be dealt with promptly rather than left until the next test cycle.
Common mistakes that cause LEV compliance problems
We often see the same issues creating avoidable risk and cost.
Treating an annual service as the same as a statutory test. Servicing supports reliability, but it does not replace a formal thorough examination and test.
Waiting for the 12 - 14-month date even though performance has changed. If the system is clearly underperforming, the calendar is not the real issue.
Making changes without reviewing the LEV. A new process, extra machine or modified hood can change the entire airflow balance.
Poor record keeping. If design criteria, test history and maintenance records are unclear, it is harder to show that control has been managed properly.
Ignoring operator feedback. The people using the process every day often notice the first signs of poor capture.
Why businesses choose Pro Vent LEV Ltd for LEV support
When you need practical help, it makes a difference to work with a business that understands LEV from design through to ongoing upkeep. Pro Vent LEV Ltd is based at Jarrow Business Centre, Viking Industrial Estate, Jarrow, and supports businesses across the UK.
We have 26 years of experience and provide support across a wide range of systems and applications, including fume extraction, dust extraction, wood waste extraction, heating and cooling ventilation systems, commercial kitchen canopy and extraction systems, heat recover ducting, food hall ventilation systems, and fabricated sheet metal ductwork.
Our work also covers P601 thorough examination and testing services, as well as ongoing LEV maintenance support. Because we design, manufacture, supply, install, commission and maintain LEV systems, we can help clients identify issues behind the test result, not just the symptom seen on the day.
If your system is approaching its due date, has been modified, or is showing signs of poor performance, early action can be far more cost-effective than waiting for downtime or disruption.
How to prepare for your next LEV examination
A little preparation can make the visit smoother and more useful. Before the examination, it helps to gather:
previous LEV test reports
maintenance and service records
details of any changes to processes or equipment
information about the substances being controlled
any recent complaints, faults or performance concerns
It is also worth checking that operators know how the system should be used. Good user practice and good engineering control need to work together.
FAQs about LEV thorough examination and testing under HSG258
Is LEV testing required every 12 - 14 months?
For most LEV systems used to control substances hazardous to health, a thorough examination and test is required at least every 12 - 14 months. Some systems or situations may need more frequent attention, especially if there are changes, defects or higher-risk conditions.
Is maintenance the same as a thorough examination and test?
No. Maintenance helps keep the system running and can identify faults, but a formal thorough examination and test is a separate compliance requirement. Both are important.
What happens if my LEV system fails its examination?
The findings should explain what is wrong and what remedial action is needed. The right response depends on the defect and the risk it creates. In some cases, prompt repair and retesting may be needed before the system can be relied on again.
Do I need a new examination if I change my process or move equipment?
If the process, material, hood position, duct layout or equipment arrangement changes, the LEV performance may also change. A review should be carried out so you can confirm the system is still effective for the new setup.
Who can help with LEV testing and maintenance in Jarrow?
Pro Vent LEV Ltd, based in Jarrow, provides LEV systems, maintenance, fume extraction, dust extraction and P601 thorough examination and testing support. You can enquire through our website or email enquiry@proventlev.co.uk.
Book an LEV inspection before small issues become bigger problems
If you are asking when your LEV system needs thorough examination and testing under HSG258, there is a good chance the answer is: soon, or sooner than you think. The 12 - 14-month interval matters, but so do the day-to-day signs that your system may no longer be delivering reliable control.
At Pro Vent LEV Ltd, we provide practical support for LEV systems, maintenance and P601 thorough examination and testing. If you want a clear view of your current compliance position, book an LEV inspection with us or email enquiry@proventlev.co.uk to discuss your requirements.
