Expert guidance
Your Fume Cupboard Questions, Answered
The questions technicians and facilities managers actually ask us, answered plainly. If yours is not here, phone and ask an engineer.
Testing & compliance
Intervals, standards, what a test involves and what happens when a unit fails.
COSHH Regulation 9 requires a thorough examination and test at intervals of no more than 14 months. Most laboratories work to a 12-month cycle so the certificate never runs close to expiry, and so the visit lands in the same term or shutdown period each year.
A measured examination of how well the cupboard contains and extracts what is generated inside it. Air velocity across the working aperture, containment performance, airflow visualisation, and the function of the alarm and monitor — assessed against BS EN 14175.
A single straightforward unit is usually well under an hour. We plan multi-unit sites so a whole lab is cleared in one visit, and we will work to your timetable rather than ours.
You are told on the day, not weeks later in a report. We label the unit, advise whether it can safely remain in use, and quote the remedial work. In most cases we can repair it rather than condemn it.
BS EN 14175 for fume cupboard performance, COSHH Regulation 9 for the duty to examine and test, BS 7989 and HSG258 for LEV, and BB88 where school buildings are involved. Which apply depends on your estate and the work being done.
Any make or model, including UK, European and US manufacturers, and we can supply the matching spares, filters and airflow monitors. We are independent, so there is no incentive to steer you towards one manufacturer.
Yes, and the reverse too. Some clients have their insurer test the equipment and ask us to service it; others have us do both. There is no requirement to buy the two together.
Servicing & maintenance
Planned visits, contracts, disruption and what is covered.
In practice they are the same work: a planned visit that keeps the unit performing rather than waiting for it to fail. We treat them as one service, which is why they share a page.
Yes. A number of clients use their insurer to test the equipment and HTS to service it. We will work alongside whoever holds the testing contract.
Please clear the working surface and remove apparatus and chemicals. Our engineers need access to the aperture, the baffles and the extract, and we are not permitted to move your chemicals for you.
Less than you would expect. Individual units go out of use only while they are being worked on, and we programme multi-unit sites so a lab is not shut for a day. Education work is usually scheduled into holidays or inset days.
Filter condition is assessed at every visit, and replacement is quoted separately because life varies so much with use. On a contract we schedule changes at agreed rates. See filters.
Both. A planned contract is the usual choice for a site with several units, because it keeps the test interval from slipping past 14 months and fixes the cost. One-off visits are equally welcome.
Repairs & breakdowns
What to do when a unit faults, and whether repair beats replacement.
If the fault could affect containment — an airflow alarm, a smell in the room, a sash that will not hold — take it out of use and label it. Do not silence a persistent alarm and carry on. Phone us and we will establish what is wrong.
Call 0113 245 4111 and we will talk through the fault immediately. Where a unit has to be taken out of service, we prioritise the visit — a laboratory with a cupboard down is losing capacity every day.
Yes. There is no requirement to be an existing service client. Tell us the make and model if you have it, or photograph the data plate, and we will tell you what we can do before we travel.
Usually, yes. A well-built cupboard has a long life and most failures are in replaceable components rather than the structure. Where a unit genuinely is beyond economic repair we will say so — that is a capital bid, and it is better to know early.
If the repair touched anything affecting airflow — fan, motor, ductwork, filters, sash geometry — the unit should be retested and the monitor recalibrated before it goes back into service. We do that as part of the job.
Often. Where the original manufacturer no longer supplies, we can usually source a compatible component or adapt one. See parts, or send a photograph of the data plate.
Yes. Ducted units are assessed on face velocity, containment and extract performance. Ductless units need all of that plus an assessment of filter saturation and breakthrough, because on a recirculating unit the filter is the containment.
Not by looking at it. Carbon gives no visual indication of saturation. We assess condition, recorded usage and elapsed time at each service visit and advise a replacement interval for your work. Waiting for a smell means waiting for breakthrough.
Treat any odour from a recirculating unit as filter breakthrough. Take it out of use and phone us before it is used again. The air returning to the room is no longer being cleaned.
No. GP carbon covers solvents, organics and alcohols, but it is not formulated for inorganic acids, ammonia, formaldehyde, mercury or iodine — each has its own grade. A general purpose filter where specialist media is required gives no meaningful protection against that substance.
Both capture particulates rather than vapours; ULPA captures a higher proportion of the very smallest particles. HEPA suits most laboratory powder and dust work. ULPA is specified where containment requirements are more demanding, typically cleanroom and pharmaceutical applications.
No. A spent filter holds everything it has captured, which makes it controlled waste, and your duty of care as the producer applies. We remove it under our waste carrier licence and issue a transfer note.
Very possibly. Filter media is specified against the substances in use at the time. A cupboard commissioned for one process and later used for another may have entirely the wrong media in it, so it is worth telling us when the work changes.
COSHH requires that control measures are maintained in efficient working order, and BS EN 14175 expects fume cupboards to have a means of indicating that airflow is adequate. In practice, a cupboard in regular use without a working monitor is very difficult to defend.
Not necessarily. It may be a genuine drop in airflow, a sash left too high, or a monitor that has drifted and is alarming at the wrong threshold. All three need measuring to tell apart. Do not silence a persistent alarm and carry on.
At every thorough examination, so at least annually, and after any work that changes the airflow — a new fan, altered ductwork, replaced filters. We recalibrate as part of the test visit rather than treating it as a separate job.
Because the factory figure was measured on a test rig with none of the things that determine airflow in your building — your duct run, bends, shared manifold, aged fan and the room’s own air movement. Calibrating in situ is the only way the alarm threshold corresponds to real face velocity.
Almost always. Retrofitting an alarm to a sound older cupboard is one of the most cost-effective safety improvements available, and considerably cheaper than replacing the unit.
No. The liner, ductwork and filter media may hold chemical residue, which makes them controlled waste. Disposal has to go through a licensed carrier, and as the producer your duty of care does not end when the unit leaves site.
Yes. Our upper tier registration number is CBDU133562 and can be checked against the Environment Agency’s public register. We would encourage you to check it, and to check any other contractor you use.
A single unit is usually a one-day job. Whole-lab clearances are programmed around your access, and most education work happens in holidays.
It can, if they share an extract manifold or fan. Removing a unit changes the system resistance and can push the remaining cupboards out of specification, so the others should be retested afterwards.
Often, yes. A sound unit can be decontaminated, moved and recommissioned in a new position, which is usually far cheaper than replacement. Whether it is worthwhile depends on the unit’s condition and the new location’s extract route.
Yes, all of them. A great deal of our work is in schools, colleges and hospitals, so it is a condition of the job rather than an optional extra.
That is when most of our education work happens. Booking early matters — holiday slots fill quickly, and a 12-month cycle keeps the visit landing in the same holiday each year rather than drifting into term time.
The legal duty is still COSHH Regulation 9. CLEAPSS guidance is what most schools are actually audited against in practice, and BB88 applies to school building ventilation. We work to all three and issue documentation that satisfies an inspection.
Whoever would have to produce them in an inspection — usually the science technician or the site manager. We issue certificates referenced to each unit’s asset number so a multi-lab site can tell at a glance which cupboard is which.
Question not answered here?
Phone and speak to an engineer rather than a call centre. Free site surveys across the UK.