By workplace & process
A single engineering workshop can weld, machine with coolant and grind on the same floor - each producing a different contaminant with its own LEV duty. Why the test has to cover every process, not just the biggest.
The short answer
An engineering workshop rarely does one thing. Welding, machining with coolant, grinding and cutting can all run on the same floor, and each produces a different contaminant - welding fume, oil mist, respirable silica and metal dust. Each needs its own capture, and the LEV test has to cover every extracted process, not just the largest or most obvious one.
The detail
Welding fume is a carcinogen - all of it, including from mild steel - and HSE requires effective control, usually local exhaust ventilation, for all indoor welding regardless of how long the job takes; the inhalable fume has a workplace exposure limit of 1 milligram per cubic metre. Metalworking fluid mist from turning, milling and grinding with coolant has no single limit, so it is controlled as low as reasonably practicable and carries its own health surveillance, being linked to asthma, hypersensitivity pneumonitis and dermatitis.
Grinding and cutting add another hazard again: respirable crystalline silica and metal dust, controlled to their own limits. Each of these processes needs a hood shaped for the job and a capture velocity suited to how the contaminant is thrown - a welding fume arm, a mist enclosure and a grinding extract are not interchangeable. A mixed workshop therefore runs several distinct LEV systems that happen to share a floor. Whether those are separate extracts or branches off one shared fan matters too, because a shared system has to move enough air for every branch drawing at once - and a branch added later, after the fan was sized, is a common reason capture falls short at one station while another looks fine.
What it means for you
A thorough examination and test of workshop LEV confirms that each extracted process is still capturing its contaminant at source and moving air at the commissioned rate - the welding extraction, the coolant mist capture and the grinding extract all checked against what each is meant to control. The duty attaches to each system, so the examiner covers them all, at least every fourteen months with user checks between.
The classic slip in a mixed workshop is to test the big, visible extraction and quietly overlook a smaller bench arm or a grinding point that is also relied on for control. If a process is controlled by LEV, that LEV has to be examined - proving every system performs, not just the headline one, is what keeps the whole floor safe.
The service behind the guide
We test engineering-workshop LEV across welding, coolant machining and grinding against the different contaminants each produces, with a clear report and remedial actions.
Questions
Because one floor can run several processes at once - welding, machining with coolant, grinding and cutting - and each gives off a different contaminant needing its own hood and capture velocity. The test has to cover them all.
All welding fume, including from mild steel, is a carcinogen. HSE requires effective control - usually LEV - for all indoor welding regardless of duration, and the inhalable fume limit is 1 milligram per cubic metre.
Metalworking fluid mist has no single limit, so it is controlled as low as reasonably practicable and carries health surveillance. Grinding and cutting can release respirable silica and metal dust, each with its own control need.
By testing the obvious big extraction and overlooking a smaller bench arm or a grinding point. If a process is controlled by LEV, that LEV has to be examined too - the duty is per system, not per site.
At least every fourteen months under COSHH, with user checks between. The examination confirms every extracted process is still capturing to its design.
Phoenix Duct Clean · by the numbers
We test engineering-workshop LEV across welding, coolant machining and grinding against the different contaminants each produces, with a clear report and remedial actions.