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LEV testing - laboratories
A fume cupboard is a form of LEV, so it falls under the same testing duty - but it is not tested like a hood over a bench. Containment, face velocity, and a performance standard of its own make it a discipline in itself.
The short answer
A laboratory fume cupboard is LEV and must be thoroughly examined and tested on the COSHH 14-month cycle - but testing it goes beyond a simple airflow reading. It means measuring face velocity across the sash, commonly to a guide of around 0.4 m/s, and assessing containment - whether the cupboard actually keeps hazardous substances inside - against the performance standard BS EN 14175. It is a more specialised examination than a standard hood check.
A fume cupboard is LEV
A fume cupboard is a form of local exhaust ventilation - it captures and removes hazardous fumes, vapours and dusts produced by laboratory work, protecting the person at the bench. So it falls squarely under COSHH: it must be maintained in efficient working order and thoroughly examined and tested at least every 14 months, like any other LEV. On the duty, a fume cupboard is treated the same as a welding fume arm or a machine hood.
But how it is tested is not the same, because a fume cupboard works differently. It is an enclosure the operator works into through a sash opening, and its job is containment - keeping what is generated inside the cupboard and away from the person. That containment function, and the performance standard behind it, make fume cupboard testing a more specialised examination than a check of a simple capture hood.
Face velocity
One central measurement is face velocity - the speed of air drawn into the cupboard across the sash opening, which is what stops fumes escaping back out towards the operator. It is measured at multiple points across the face to check it is adequate and even, not just adequate on average. A common working guide is a face velocity of around 0.4 metres per second, though the right figure depends on the cupboard and its use.
Face velocity that is too low lets contaminant escape; too high can cause turbulence that actually worsens containment, so it has to sit within the designed range, not simply be as strong as possible. Measuring it properly, across the whole face, is part of what distinguishes a real fume cupboard test from a single reading taken at one convenient spot.
Containment
Face velocity is a good indicator, but the question that ultimately matters is containment: does the cupboard actually keep hazardous substances inside the working area and away from the operator. A cupboard can have an acceptable face velocity and still leak contaminant out through turbulence or poor design, so containment is assessed more directly - checking whether substances generated inside stay contained rather than escaping into the lab.
This is the heart of why a fume cupboard needs testing beyond a standard airflow check. The whole purpose of the cupboard is to contain, and only a proper examination - measuring face velocity across the face and assessing containment - confirms it is doing that. A test that reads airflow and stops there has not really tested the one thing the cupboard exists to do.
BS EN 14175
Sitting behind fume cupboard testing is BS EN 14175, the standard governing the design, performance and testing of ducted fume cupboards. It defines how a fume cupboard should perform in the first place, and provides the technical basis for assessing whether an installed cupboard is meeting that performance. So while COSHH sets the requirement for ongoing testing, BS EN 14175 sets the benchmark the testing measures against.
The two work together, much as COSHH and HSG258 do for general LEV: COSHH says it must be tested, BS EN 14175 says what good performance looks like. A proper fume cupboard test therefore assesses the cupboard against that performance standard, not just against a generic airflow expectation - which is another reason it is a specialised examination rather than a routine hood check.
The takeaway
For a laboratory, the key point is that a fume cupboard is LEV that needs testing on the COSHH cycle, but testing it properly means more than an airflow reading - it means measuring face velocity across the sash, assessing containment, and doing so against the BS EN 14175 performance standard the cupboard is meant to meet. That is the examination its containment role requires.
So a fume cupboard should be tested by someone competent to do that specialised assessment, not treated as an ordinary hood. Getting it right confirms the cupboard is genuinely containing the hazards the lab works with - protecting the people at the bench, which is the entire reason the cupboard is there. Beyond the standard LEV check is exactly where fume cupboard testing needs to go.
Questions
Yes. It captures and removes hazardous fumes and dusts to protect the operator, so it falls under COSHH and must be thoroughly examined and tested at least every 14 months, like any other LEV.
Beyond a simple airflow reading - by measuring face velocity across the sash at multiple points, and assessing containment (whether it actually keeps substances inside), against the BS EN 14175 performance standard.
A common working guide is around 0.4 metres per second across the sash, measured at multiple points - but the right figure depends on the cupboard and its use, and it must sit within the designed range, not simply be as strong as possible.
An assessment of whether the cupboard actually keeps hazardous substances inside the working area and away from the operator. A cupboard can have acceptable face velocity and still leak through turbulence, so containment is checked more directly.
The standard governing the design, performance and testing of ducted fume cupboards. It defines how a cupboard should perform, providing the benchmark that testing measures against - while COSHH sets the requirement to test.
Because its job is containment, and only measuring face velocity across the face and assessing containment against BS EN 14175 confirms it is doing that. A test that reads airflow and stops has not tested the thing the cupboard exists to do.
We test fume cupboards on the COSHH cycle - face velocity and containment against BS EN 14175 - the examination their role requires.
