Ductless Fume Cupboards

A ductless fume cupboard, or recirculating fume cupboard, is a standalone laboratory enclosure designed to contain hazardous gases, vapours and particulates generated during chemical tests. It uses HEPA, ULPA or carbon filters to capture toxic fumes before recirculating clean air back into the lab, protecting laboratory technicians from fume inhalation without the need for external ductwork. This makes it a practical choice where ducting to the outside of the building is impractical, costly or restricted by the building itself.

Because filtration happens entirely within the cabinet, a ductless fume cupboard suits low-volume, low-risk applications such as quality control, forensic work and inert manufacturing processes, rather than high-volume or highly corrosive chemical use. Filter selection matters here: carbon filters target solvents, acids and other vapours, while HEPA and ULPA filters capture particulates such as powders and dust, and TION can advise on the right combination for your specific process. For more information, visit "Is a Ductless Fume Hood Right for My Laboratory."

A ductless fume cupboard removes airborne particles, gases and vapours through high capacity carbon, ULPA or HEPA filters. An internal fan draws air through the sash away from the user, pulling it through a filter or combination of filters before recirculating clean air back into the lab. The choice of filter depends on the hazard involved: carbon handles solvents, acids and other chemical vapours, while HEPA and ULPA target particulates such as powders and dust. Airflow is continuously monitored through the control panel, which alerts users if performance drops below a safe threshold or a filter needs changing.

Because no external ducting is required, a ductless fume cupboard is usually quicker and simpler to install than a ducted one, with no ductwork design, routing or planning permission to account for. This also keeps running costs lower and makes the unit straightforward to reposition if your lab layout changes, with recommissioning rather than a full reinstall needed at the new location.

A ductless or recirculating fume cupboard can be fitted with a carbon or HEPA filter, and sometimes a combination of both, depending on the hazard involved. Carbon filters are effective against acids, solvents and other chemical vapours, with different carbon blends available for specific compound types. HEPA filters remove particulates, such as powders and dust, but do not capture chemical vapours in the way carbon does, which is why some processes call for both filter types fitted together.

Which filter you choose depends entirely on the process taking place inside the cabinet, not on the cabinet itself. Using the wrong filter type, or a filter unsuited to the volume and concentration of chemical involved, can leave the user without effective protection even if the unit appears to be running normally. If you are unsure which filter you require, please contact us and we will be happy to help you match the right filtration to your application.

A ductless or recirculating fume cupboard is a self-contained fume extraction unit. The process of scrubbing harmful toxins from the air takes place inside the cabinet via a HEPA or carbon filter, with clean air returned directly to the lab rather than expelled outside. A ducted fume cupboard works differently: it requires a functional air duct to carry contaminants from the lab to an exhaust stack outside the building, so nothing is recirculated at any point.

That distinction shapes which unit suits which application. Ducted systems can handle a wider range and higher volume of chemicals since contaminated air never re-enters the room, but they need ductwork, often planning permission, and a fixed installation position. Ductless systems install faster, cost less upfront and can be relocated, but are limited to low-volume, low-risk chemical use given the recirculation involved. For more information, please visit "Choosing Ducted Vs Ductless Fume Cupboards".

No. Although a ductless fume cupboard can facilitate acids, the filters, whether carbon or HEPA, inside the cabinet degrade over time with continued use. This degradation allows small pockets of particles and vapour to pass through untreated, gradually reducing the level of protection the unit provides even though it may still appear to be operating normally.

For this reason, we only recommend using mild to moderate chemical strengths at low volumes in a ductless unit. You should question anything below five ppm, and where usage sits close to that threshold, more frequent filter checks and DOP testing become essential rather than optional. Regular monitoring of filter saturation, alongside a clear internal process for ordering replacements, keeps the cabinet performing as intended throughout its working life. If your application involves stronger concentrations or higher volumes, a ducted fume cupboard is the safer and more appropriate choice.

Installing a ductless fume cupboard is usually a simple process and can be completed in as little as a day. It's the fume extraction equivalent of a modern plug-and-play system, allowing engineers to position and commission the cabinet without ductwork, planning permission or the lead time a ducted installation typically requires.

Commissioning still matters, even without ducting to fit. Engineers check airflow performance against BS EN 17242, set filter change and service timers on the control panel, and confirm the alarm system is functioning correctly before handover. This is one of the main reasons ductless units suit labs that need equipment up and running quickly, or that expect to relocate cabinets as space requirements change, since recommissioning at a new location follows the same straightforward process.

Generally, a ductless fume cupboard will cost anywhere from £6,000 to £10,000, depending on the complexity and size of the unit. Factors such as filter type, control panel specification, worksurface material and any bespoke dimensions or customisation all affect where a unit falls within that range. As a guide, a ductless fume cupboard typically costs around half as much as a ducted equivalent of similar size once installation and ductwork are factored into the ducted price.

Ongoing costs are mostly limited to filter replacement, which varies depending on the chemicals and volumes involved in your process, so it's worth discussing expected filter life with your supplier before purchase rather than after. For more information, visit "How Much Does A Fume Cupboard Cost?"