LEV Testing & Compliance for Welding Fume Extraction

LEV testing — formally a “thorough examination and test”, often shortened to TExT — is a statutory inspection of any engineering control used to capture airborne contaminants at source. Under COSHH Regulation 9, where LEV is provided to control exposure, the employer must keep it in efficient working order and in good repair, have it thoroughly examined and tested at suitable intervals, and keep a record of each examination for at least five years.

For most LEV the maximum interval is 14 months (chosen so an annual test gradually shifts through the calendar rather than always falling in the same busy period). Some high-risk processes require more frequent testing, but welding fume extraction falls under the standard 14-month maximum. The interval is a backstop, not a target — if your COSHH assessment or the system’s condition warrants it, you test sooner.

The duty applies regardless of how the fume is captured — whether you use on-torch, mobile or fixed extraction arms. If it is there to control exposure to a substance hazardous to health, it must be tested.

A competent examiner works to a defined three-part method, set out in the HSE’s guidance HSG258, “Controlling airborne contaminants at work” — the recognised reference for LEV examination in the UK.

• A thorough visual and structural examination. The examiner checks the whole system — hoods and capture points, ducting, dampers, the filter or air cleaner, the fan, and any discharge or recirculation — for damage, wear, corrosion, leaks, blockages and signs of poor use. They confirm it matches what the COSHH assessment assumed.
• Measurement of technical performance. Using calibrated instruments, the examiner measures the system’s actual performance — typically capture velocity at the point of fume generation, face velocity at hoods or booths, duct transport velocities and static pressures. These figures are compared against the commissioning benchmark recorded when the system was installed. A meaningful drop from those original values signals a problem even if air is still clearly moving.
• An assessment of effectiveness. The examiner forms a judgement on whether the system, as found, still adequately controls the contaminant in normal use — and records any remedial action needed, with a clear pass or fail.

The output is a signed report stating what was tested, the readings taken, whether the LEV is effective, and what (if anything) must be put right. That report is the record you keep for five years and the document an HSE inspector will ask to see.

A thorough test is only as meaningful as the benchmark it is measured against. When LEV is first installed it should be commissioned — its design performance verified and the key velocities and pressures recorded — and supplied with a user manual and a logbook. The commissioning figures are the baseline every future examination compares to: without them, an examiner can only say the system is moving air, not whether it still performs as designed.

The logbook is the running history of the system — checks, maintenance, filter changes and faults. Keep it up to date and stored with the user manual. If you inherit a system with no commissioning data, a competent examiner can establish a fresh baseline, but you lose the ability to detect gradual decline against the original design. Treat the commissioning report, manual and logbook as part of the equipment.

COSHH requires a competent person, but does not name a single qualification. In practice, the recognised benchmark for LEV examiners in the UK is the BOHS P601 qualification (“Initial Appraisal and Thorough Examination and Testing of Local Exhaust Ventilation Systems”) from the British Occupational Hygiene Society. A P601-qualified examiner has demonstrated they understand LEV principles, can use the test instruments correctly, and can interpret results against HSG258. Asking whether an examiner holds P601 is a reasonable way to check competence.

It is also worth knowing the equipment standard BS EN ISO 21904, which covers equipment for the capture and separation of welding fume. Specifying and buying extraction to this standard makes systems easier to commission, benchmark and examine over their life.

The 14-month test is a periodic check, not a substitute for everyday upkeep. As the user or employer you are responsible for keeping the LEV in efficient working order day to day, which means:

• Routine visual checks before use — that hoods are correctly positioned, arms reach the work, indicators (where fitted) read normal, and nothing is obviously damaged or blocked.
• Filter maintenance — cleaning or replacing filters per the manual; a blinded filter is one of the most common reasons capture quietly fails. As filters load with welding fume and dust, airflow gradually reduces, the fan has to work harder to maintain flow, and energy and running costs rise — so a system that is not maintained may no longer provide effective control. See the depth on filters below.
• Training — making sure welders know how to position the capture point close to the arc and use the system correctly; even excellent LEV fails if the hood is left a metre from the weld.
• Reporting and acting on defects — recording faults in the logbook and fixing them promptly, not waiting for the next statutory test.

These duties form part of your wider obligations under welding regulations and COSHH.

The filter is where contaminated air is cleaned before it is discharged or recirculated, so it does the actual job of removing hazardous airborne particles. Welding fume is made up of extremely fine particles, many invisible to the naked eye, and the filter captures them as the air passes through the media while the cleaned air exits the system. Get the filter wrong, or let it deteriorate, and fume stays in the workplace and people stay exposed.

Most welding fume systems use several stages of filtration, and the right arrangement depends on the process, the materials being welded and the level of filtration required:

• Pre-filters remove larger particles before they reach the main filter — protecting it, extending its life and reducing overall maintenance cost.
• Cartridge filters are pleated, cylindrical filters that pack a large filtration surface into a compact space; they are widely used in industrial welding extraction for their efficiency, long service life and relatively low maintenance.
• HEPA (High Efficiency Particulate Air) filters remove extremely small particles with very high efficiency, and are used where very clean discharged air is required or particularly fine particles are generated. Whether you need one depends on the process, your workplace risk assessment and the system design — stainless steel and laser welding, for instance, tend to produce especially fine particles that warrant high-performance filtration.

Filters do not last forever. They gradually become loaded with captured fume and dust, and as they do, airflow falls unless they are cleaned or replaced in line with the manufacturer’s recommendations. Filter life varies with welding volume, materials and contamination, so regular inspection — not a fixed calendar — is the best way to judge when to replace; waiting until airflow has visibly dropped means capture has already been compromised. Tell-tale signs include reduced airflow, poor fume capture, increased fan noise, or a filter condition indicator (where fitted) reading high. Some industrial cartridge filters are designed to be cleaned — manually, or automatically using pulses of compressed air to shed dust from the surface during operation — while others are intended to be replaced; always follow the manufacturer’s guidance to avoid damaging the media. Used filters should be disposed of according to the manufacturer’s recommendations and your waste procedures, since the captured materials govern the disposal route.

The statutory 14-month examination is a backstop; planned servicing in between is what keeps the system performing close to its original design and heads off unexpected failures. Routine maintenance typically covers:

• Airflow — measuring it periodically, since tracking it over time reveals gradual decline before it becomes significant.
• Ducting — inspecting for damage, leaks and blockages, any of which reduce airflow and capture; damaged ductwork can cut performance markedly.
• Filters — inspecting, cleaning or replacing as above.
• Extraction arms — checking they move freely, stay where positioned and show no damage; a well-behaved arm encourages correct use and better capture.
• Fans and controls — confirming fans run correctly and controls function, and acting on warning signs such as unusual noise or vibration that can point to worn bearings, imbalance or loose components.

If extraction airflow has dropped, the usual culprits are blocked filters, damaged or leaking ducting, air leaks, worn fans or restrictions in the system, and a systematic inspection normally finds the cause. Where a system can no longer perform adequately, targeted upgrades — replacement extraction arms, improved filtration, higher-performance fans or revised ductwork — are often a more cost-effective route than full replacement.

LEV testing proves the equipment performs to specification. Personal exposure monitoring — air sampling in the welder’s breathing zone, assessed against Workplace Exposure Limits — proves the controls are actually protecting people in real conditions. The two are complementary: a system can pass its TExT yet still leave a welder over-exposed if it is used poorly, so periodic exposure monitoring is a valuable check that your controls work in practice, and it feeds back into your COSHH risk assessment.

Keeping welding fume extraction compliant takes the right test schedule, good records and a competent examiner — and, in between examinations, a system that is properly maintained. Through Extractability, Weldability SIF provides practical advice on welding fume control, LEV and COSHH duties, and on selecting, maintaining and getting the best from Fumex extraction systems. That support covers routine servicing and maintenance — airflow checks, ducting inspection, filter selection and replacement, and extraction-arm and fan checks — as well as assessing an existing installation to identify upgrades such as replacement arms, improved filtration, higher-performance fans or revised ductwork.

The statutory thorough examination and test itself must be carried out by a competent person, so where you need the formal 14-month TExT, we can help you understand what it involves and keep your system in the condition to pass it. To talk through maintaining your LEV or choosing the right Fumex system, get in touch with our team. To choose or upgrade a system in the first place, see our guide to the types of welding fume extraction.