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LEV testing - foundries
A foundry is one of the harshest environments LEV has to work in. The processes - moulding, casting, knockout, fettling - generate respirable silica dust and metal fume, some of the most serious airborne hazards there are, and they do it in punishing heat, with abrasive dust and vibration attacking the extraction system itself. Controlling exposure here is demanding, which is exactly why testing matters.
The short answer
Foundries generate two of the most serious airborne hazards: respirable crystalline silica from the sand used in moulding, casting, knockout and fettling - with a workplace exposure limit of just 0.1 mg/m3, and studies showing knockout and mould-shop work can reach and exceed that limit - and metal fume driven off molten metal. LEV has to control these in extreme conditions: high heat, abrasive dust that wears components, and heavy use. Those same conditions degrade the extraction over time, so a thorough examination and test - confirming the LEV is still controlling these serious hazards despite the punishment - is especially important in a foundry.
The hazards
Foundry work generates two grave airborne hazards. The first is respirable crystalline silica. Foundries use sand - which contains silica - for moulds and cores, and the processes that handle it throw fine silica dust into the air: mixing and forming moulds, the violent knockout of castings from their sand moulds, and the fettling and grinding that finishes castings. The respirable fraction of this dust - the particles small enough to reach deep into the lungs - causes silicosis, an irreversible and disabling lung disease, and is linked to lung cancer. Its workplace exposure limit is just 0.1 mg/m3, a very low figure that reflects how harmful it is.
The second hazard is metal fume. Melting and pouring metal drives off metal fume - fine particles of metal and metal oxides formed as hot metal vaporises and the vapour condenses in the air. Depending on the metals involved, this fume carries its own serious health risks. So a foundry worker faces silica dust from the sand and metal fume from the molten metal, both at once, both serious. These are not nuisance dusts to be tidied away; they are among the most harmful things a workplace can put into the air, and controlling them is a health imperative, not a housekeeping preference.
How serious the silica exposure is
The scale of the silica problem in foundries is well documented. The exposure limit for respirable crystalline silica is 0.1 mg/m3 as an eight-hour average - already a low, demanding figure - and foundry processes are quite capable of exceeding it. Studies of foundry work have found respirable silica in mould-shop operations reaching well above the limit, and knockout processes - the violent separation of the casting from its baked sand mould - among the highest-exposure activities, at times exceeding the occupational limit. In other words, without effective control, foundry workers can be exposed above the level the law sets as the ceiling.
That is what makes the LEV in a foundry so critical. The gap between an uncontrolled foundry process and the exposure limit is large, so the control has to do real work - it is not trimming a minor exposure but bringing a potentially serious one down to acceptable. Effective extraction at the dustiest processes - knockout, fettling, moulding - is what stands between the worker and a silica exposure that can be several times the limit. And because the limit is so low and the consequence so grave, the control has to be genuinely effective and reliably maintained, not merely present. There is little margin for a system that is under-performing.
Why the conditions punish the LEV
A foundry does not just present serious hazards - it presents them in conditions that are brutal for the extraction system itself. The heat is extreme, near molten metal and hot castings, which stresses ductwork, fans and components. The dust is abrasive - silica sand is hard and gritty - so it wears the inside of ducts, erodes fan impellers and abrades moving parts as it passes through the system. And the use is heavy and continuous. All of this degrades the LEV faster than it would in a gentler setting.
That accelerated degradation is the crucial point. The same abrasive dust the LEV is capturing is wearing the LEV out - eroding the impeller that moves the air, thinning the ductwork, wearing components - so the system's performance declines over time under the very conditions it exists to handle. Heat adds thermal stress; heavy use adds ordinary wear at an accelerated rate. So a foundry LEV that was effective when installed can lose performance faster than most, precisely because its environment is so harsh. The extreme conditions that make the extraction necessary are the same conditions that undermine it - which is why keeping it working takes active attention.
Why testing matters here especially
Put the two together - some of the most serious airborne hazards there are, controlled by a system that its own environment is actively wearing out - and the case for rigorous testing in a foundry is overwhelming. A thorough examination and test measures the airflow and capture velocity at the hoods and confirms the LEV is still controlling the silica and fume despite everything the foundry throws at it. Given how low the silica limit is and how fast the harsh conditions degrade the system, that periodic confirmation is not a formality here; it is the check that the control has not quietly fallen behind the wear.
It also means a foundry cannot rely on an LEV having been effective once. Because the abrasive, hot, heavy-use environment degrades the system faster than most, a foundry LEV needs its performance confirmed on its cycle and its condition watched closely between tests - an eroded impeller, a worn duct, a declining fan showing up as measured airflow that has dropped below the benchmark. In a setting where the hazards are this grave and the conditions this punishing, the measured test is what stands between a foundry that believes its workers are protected and one that knows they are. The seriousness of the hazards demands the certainty that only measurement gives.
The takeaway
A foundry generates two of the most serious airborne hazards there are - respirable crystalline silica from the sand, with an exposure limit of just 0.1 mg/m3 that uncontrolled processes like knockout and fettling can exceed, and metal fume from molten metal - and it does so in extreme heat, with abrasive dust and heavy use punishing the extraction system itself. Controlling exposure here is demanding, and the same conditions that make the LEV necessary degrade it faster than most.
That combination - grave hazards controlled by a system its own environment is wearing out - is exactly why testing matters so much in a foundry. A thorough examination and test measures the airflow and capture velocity and confirms the LEV is still controlling the silica and fume despite the punishment, and close attention between tests catches the accelerated wear. Where the hazards are this serious and the conditions this harsh, the measured test is what turns a hope that workers are protected into knowledge that they are.
Questions
Two grave ones: respirable crystalline silica from the sand used in moulding, casting, knockout and fettling, which causes silicosis and is linked to lung cancer; and metal fume driven off molten metal during melting and pouring. Both are among the most serious hazards a workplace can put into the air.
Respirable crystalline silica has a workplace exposure limit of 0.1 mg/m3 as an eight-hour average - a very low figure reflecting how harmful it is. Studies show foundry processes like knockout and mould-shop work can reach and exceed this limit without effective control.
Knockout is the violent separation of a casting from its baked sand mould, which throws large amounts of fine silica dust into the air. Studies have found it among the highest-exposure foundry activities, at times exceeding the occupational limit - which is why effective extraction there is so important.
Because they are brutal for the system: extreme heat near molten metal stresses components, abrasive silica sand wears the ductwork and erodes fan impellers as it passes through, and heavy continuous use adds accelerated wear. The same dust the LEV captures is wearing the LEV out.
Yes. The abrasive dust erodes impellers and thins ductwork, the heat adds thermal stress, and heavy use accelerates ordinary wear. So a foundry LEV that was effective when installed can lose performance faster than in gentler settings - which is why its condition needs close attention.
Because grave hazards are being controlled by a system its own harsh environment is actively wearing out. The thorough examination measures the airflow and capture velocity and confirms the LEV is still controlling the silica and fume despite the punishment - certainty that matters most where the hazards are this serious.
Our thorough examination measures whether your foundry LEV is still controlling silica and metal fume despite the heat, abrasion and heavy use that wear extraction systems out faster than most settings.
