COSHH, law & TExT
Booked in your first LEV test and unsure what the engineer will actually do? It is a structured, three-stage assessment - not a glance at a gauge.
The short answer
HSG258 structures a thorough examination and test in three stages: a thorough visual and structural examination, a review of technical performance against the system's benchmarks, and an assessment of whether the system still controls exposure at source. Reading a test report without understanding those stages is where most duty holders lose ground in an inspection conversation - so it helps to know what an examiner is doing on the day.
The detail
Stage one is a hands-on examination of the whole system - hoods, ducting, dampers, any filter or air cleaner, the fan and the discharge - checking that it is in good repair, clean and in efficient working order, and looking for the tell-tale faults: holes in ducting, blocked filters, dislodged hoods, a labouring fan.
Stage two measures performance with calibrated instruments and compares it against the commissioning data or design specification: capture and face velocities at the hood, and transport velocities in the ducts that keep dust airborne rather than settling out. Stage three is the judgement that ties it together - given those readings, is exposure still being controlled at source? Test points are photographed and every value recorded.
What it means for you
The output is a written report stating what was measured, a clear pass or fail, any remedial actions, and the date the next test is due. Where a defect prevents effective control, HSG258 supports visible failed labelling on the affected hood and an emergency written report, and the affected process should stop until the system is made safe.
A good report is legible to a manager, not just an engineer. It should let you see at a glance which hoods passed, which need work and by when - and it should be filed with your logbook so the whole history reads as one continuous record.
One practical point is often missed: a report is only as useful as the baseline it is measured against. Where a system has no commissioning data, the examiner has to judge performance against design intent or professional expectation and say so - and that missing reference point is itself worth fixing, because it weakens every future test.
The service behind the guide
Our examiners follow the HSG258 three-stage method and calibrate their kit, then write the findings up so you can act on them - clear on what passed, what failed and what to fix first.
Questions
A thorough visual and structural examination; a review of technical performance against commissioning or design data; and an assessment of control effectiveness - whether the system still controls exposure at source. HSG258 sets out all three.
Airflow performance using calibrated instruments - capture and face velocities at the hoods and transport velocities in the ducting - compared against the system's benchmarks. Filter condition, fan performance and general repair are also assessed.
It depends on the number of hoods and the complexity of the system, since every capture point is examined and measured. A small single-hood system is quick; a large multi-hood workshop takes considerably longer.
The report records it as a fail with remedial actions. Where a defect stops the system controlling exposure, HSG258 supports a failed label and an emergency report, and the affected process should stop until it is put right.
A written report listing measured values, a pass or fail for each part, recommended actions and the next test due date - which should be filed alongside your LEV logbook.
Phoenix Duct Clean · by the numbers
We work through every stage HSG258 sets out, measure with calibrated instruments and hand back a report you can act on - not a tick box. Call or email for a quote.