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LEV testing - stonemasonry
Cutting, grinding and shaping stone is skilled, satisfying work - but it releases respirable crystalline silica, one of the most damaging dusts a worker can breathe. Silica dust scars the lungs, causing silicosis, and the disease is irreversible. LEV that captures the dust at source is, quite literally, lung-saving - and testing it is how you know it is doing that job.
The short answer
Stonemasonry - cutting, grinding and shaping stone - releases respirable crystalline silica, the fine fraction of stone dust that reaches deep into the lungs. Silica is one of the most harmful workplace dusts: it causes silicosis, an irreversible, disabling lung disease, and is linked to lung cancer, with a workplace exposure limit of just 0.1 mg/m3 reflecting its danger. Engineered stone, now common in worktops, is especially silica-rich and has caused a resurgence of the disease. LEV that captures the dust at the point of cutting or grinding, often alongside water suppression, is what controls the exposure - and a thorough examination and test confirms it is genuinely protecting the mason's lungs.
The dust behind the craft
Stonemasonry is an old and skilled craft, but the material it works carries a serious hidden hazard. Most stone - sandstone, granite, slate, and the engineered stone now common in kitchen worktops - contains crystalline silica, and cutting, grinding, drilling and shaping it releases that silica as dust. The dangerous part is the respirable fraction: the particles fine enough to travel deep into the lungs, too small to see, produced in abundance by power tools working stone. This is not the visible grit that settles on surfaces but the invisible fine dust that hangs in the air and is breathed in.
That respirable silica is what makes stone dust so hazardous, and the mechanised nature of modern stonework makes it worse. Power saws, grinders and polishers working stone generate large quantities of fine dust quickly - far more than hand tools ever did - so a mason using modern equipment on silica-bearing stone can be exposed to a great deal of respirable silica unless it is controlled. The craft that produces beautiful, durable work also produces one of the most damaging dusts there is, and the people doing it are exposed to it every working day. Understanding that the stone dust is respirable silica, and what that means, is the starting point for taking its control seriously.
What silica does to lungs
Respirable crystalline silica causes silicosis - a disease in which the fine silica particles lodged deep in the lungs cause scarring of the lung tissue. That scarring is permanent and progressive: silicosis is irreversible, it can worsen even after exposure stops, and in its severe forms it is disabling and can be fatal. Silica exposure is also linked to lung cancer and other serious respiratory disease. This is not a mild or theoretical hazard - it is one of the most significant occupational lung diseases there is, caused directly by breathing the dust that stonework releases. The stakes with silica are a worker's lungs, permanently.
The seriousness is reflected in the exposure limit. Respirable crystalline silica has a workplace exposure limit of just 0.1 mg/m3 as an eight-hour average - a very low figure, set low precisely because the dust is so harmful. Keeping a mason's exposure below that, and as far below as reasonably practicable, takes real control, because uncontrolled stonework can produce silica well above the limit. A particular modern concern is engineered stone - the quartz-based material widely used for worktops - which has a very high silica content and has caused a resurgence of silicosis, including severe cases in relatively young workers who fabricate it. The hazard is not historical; it is very much present wherever silica-bearing stone is worked.
How the exposure is controlled
Controlling silica dust in stonework relies on capturing or suppressing it at the point it is created. LEV does this by extracting the dust at source - on-tool extraction, where a shroud around the cutting or grinding tool draws the dust away as it is produced, or extraction at the workstation catching the dust where the work is done. The aim, as with any LEV, is to capture the respirable dust before it reaches the mason's breathing zone, drawing it into the extraction rather than letting it disperse into the air the worker breathes. For a hazard this serious, that capture at source is the front-line control.
Water suppression is the other common measure, often used alongside extraction: feeding water to the cutting or grinding point damps the dust down, so much of it is captured in the water rather than becoming airborne. Water suppression and LEV each attack the dust, and they are frequently used together - water to knock down what it can, extraction to capture the airborne fraction. Which combination is right depends on the work, but the principle is that silica dust has to be controlled at source by damping, capturing, or both, because letting it become airborne and then relying on general ventilation is nowhere near enough for a hazard with a limit as low as silica's. The control has to be effective and close to the source, which is exactly what has to be confirmed.
Why testing the LEV matters
Where LEV is the control for silica dust, testing it is confirming that a lung-saving control is actually working - which, given what is at stake, could hardly matter more. The exposure limit is very low, the disease it guards against is irreversible, and the dust that matters is invisible, so you cannot judge by eye whether the extraction is capturing it. A thorough examination and test measures the extraction's performance - the airflow and capture at the source - and confirms it is genuinely controlling the respirable silica, rather than leaving it assumed from a system that is merely running. For silica, that confirmation is the difference between protection and false reassurance.
The strict limit and the severity of the disease mean there is very little margin for an LEV that is under-performing. A system that captures most of the silica but not enough still leaves a worker exposed above a limit set deliberately low, accumulating the dust that scars lungs. So the effectiveness of the extraction has to be genuinely adequate, not roughly adequate - and only measurement establishes that. Testing the LEV on silica-generating stonework is therefore not a formality but a direct check that the control standing between the mason and silicosis is doing its job. Given that the alternative is irreversible lung disease, confirming the lung-saving control actually saves lungs is exactly what the testing is for.
The takeaway
Cutting and grinding stone releases respirable crystalline silica - the invisible fine fraction that reaches deep into the lungs and causes silicosis, an irreversible, disabling disease, with a workplace exposure limit set at just 0.1 mg/m3 because the dust is so harmful. Engineered stone, common in modern worktops, is especially silica-rich and has driven a resurgence of the disease. The hazard behind the craft is one of the most serious a worker can face, and it is very much present today.
LEV that captures the dust at source - on-tool or workstation extraction, often alongside water suppression - is what controls the exposure, and given the severity of the disease and the strictness of the limit, it is genuinely lung-saving. Because the dust is invisible and the margin for under-performance is tiny, a thorough examination and test to confirm the extraction is actually capturing the respirable silica is what turns a hope of protection into knowledge of it. For a hazard where the alternative is irreversible lung disease, testing the control that stands between the mason and silicosis is exactly what matters.
Questions
Because it contains respirable crystalline silica - the fine fraction that reaches deep into the lungs. Cutting, grinding and shaping stone releases it in abundance, and it causes silicosis, an irreversible, disabling lung disease, and is linked to lung cancer. The exposure limit is set at just 0.1 mg/m3 to reflect the danger.
A disease in which fine silica particles lodged deep in the lungs cause permanent, progressive scarring of the lung tissue. It is irreversible, can worsen even after exposure stops, and in severe forms is disabling and can be fatal. It is caused directly by breathing the respirable silica that stonework releases.
Yes. Engineered stone - the quartz-based material widely used for worktops - has a very high silica content and has caused a resurgence of silicosis, including severe cases in relatively young workers who fabricate it. The hazard is not historical; it is very much present wherever silica-rich stone is worked.
By capturing or suppressing it at source. LEV extracts the dust as it is produced - on-tool extraction with a shroud around the tool, or workstation extraction - and water suppression damps the dust down by feeding water to the cutting point. The two are often used together, water to knock down dust and extraction to capture the airborne fraction.
Because it is a lung-saving control guarding against an irreversible disease, the exposure limit is very low, and the dust is invisible - so you cannot judge by eye whether the extraction is capturing it. A thorough examination measures the performance and confirms it is genuinely controlling the respirable silica.
Very little. The limit is set deliberately low and the disease is irreversible, so a system capturing most but not enough of the silica still leaves a worker exposed above the limit, accumulating the dust that scars lungs. The extraction has to be genuinely adequate, which only measurement establishes.
Our thorough examination confirms your stonework extraction is genuinely capturing the respirable silica at source - the lung-saving control between your masons and irreversible silicosis, proven to work rather than assumed.
