By workplace & process
A dental or medical lab generates two different hazards from the same benches - vapour from acrylic monomer and dust from grinding alloys and acrylics. Each needs its own kind of capture, and the test has to confirm both.
The short answer
Dental and medical laboratories give off vapour and dust at the same workstations. Acrylic monomer releases methyl methacrylate vapour when it is mixed, poured and cured, while grinding and trimming acrylics and metal alloys throws off fine dust. The two behave differently in the air, so one hood rarely controls both well - and the LEV test has to confirm capture for each.
The detail
The vapour is mainly methyl methacrylate, the monomer used in denture and appliance work. It has a workplace exposure limit of 50 parts per million as an eight-hour average and 100 parts per million over fifteen minutes, it is a skin sensitiser, and it irritates the eyes, nose and upper airways - with chest tightness and wheeze reported on higher short-term exposures. Because it is a sensitiser, keeping day-to-day exposure low matters as much as staying under the number.
The dust is a mix. Grinding acrylic produces fine particulate, and grinding cobalt-chromium and nickel alloys produces metal dust containing recognised sensitisers and suspected carcinogens; investment and refractory materials add silica, and plaster work adds more dust again. That metal and mineral dust is not a nuisance to be tolerated - it has to be captured effectively in its own right.
What it means for you
A thorough examination and test of lab LEV confirms two things: that local capture at pouring and curing is holding the monomer vapour, and that bench downdraft or on-tool extraction is catching the grinding dust at source. Dust thrown at speed and vapour that drifts need different capture geometry and velocity, so the examiner checks each against what it is meant to control, at least every fourteen months and with user checks between.
The common failing is a single general extract expected to do both jobs, or a dust bench that has lost airflow so fine particulate escapes into the breathing zone. Proving the capture still performs for both the vapour and the dust - rather than assuming a busy bench is protected - is the point of the test. Because the two exposures come and go with different tasks through the day, the examiner also looks at how the extraction copes when several benches run at once, not just one station in isolation.
The service behind the guide
We test dental and medical lab LEV - bench extraction, capture arms and downdraft - against both the monomer vapour and the grinding dust it has to control, with a clear report.
Questions
Two kinds at once: vapour from methyl methacrylate monomer used in acrylics, and dust from grinding acrylic and cobalt-chromium or nickel alloys, plus silica from investment materials. They need different capture.
Methyl methacrylate has a workplace exposure limit of 50 parts per million as an eight-hour average and 100 parts per million over fifteen minutes. It is a skin sensitiser and an irritant to the eyes, nose and airways.
Dust from grinding is thrown at speed and is best caught by downdraft benches or on-tool extraction close to the wheel. Vapour spreads from pouring and curing and needs local capture at that point. One hood rarely does both well.
Yes. Grinding cobalt-chromium and nickel alloys produces dust containing sensitisers and suspected carcinogens, so that extraction has to be effective in its own right, not treated as a nuisance.
At least every fourteen months under COSHH, with user checks in between. The test confirms both the vapour capture and the dust extraction are still performing to the design.
Phoenix Duct Clean · by the numbers
We test dental and medical lab LEV - bench extraction, capture arms and downdraft - against both the monomer vapour and the grinding dust it has to control.