Chemical fume hoods, lab fume hoods, ductless fume hoods including a ductless fume hood for lab bench use, a fume hood cabinet and biosafety cabinets: choosing which enclosure the work needs, what the fume hood vs biosafety cabinet and biosafety cabinet vs fume hood question is really asking about who is being protected, and why a fume hood lab decision is a hazard decision

Deciding which enclosure

1. Start from the hazard, not the catalogue. Chemical vapour, biological aerosol, particulate, radionuclide and combinations of these each point at a different enclosure, and some combinations need a specific type such as a ducted cabinet. Write down what is actually handled, in what quantity, before looking at any product.
2. Chemical fume hood for chemical vapour. A ducted chemical fume hood draws air away from the operator and exhausts outside, which handles volatile and toxic chemistry. It offers no product protection at all, so it cannot be used to keep a culture sterile.
3. Biosafety cabinet for biological aerosol. Cabinets are classed by what they protect and how they exhaust, and the class required follows from the agent and the containment level. Most recirculate through a filter, which means a cabinet is not a substitute for a fume hood when volatile chemicals are involved unless it is specifically a ducted type.
4. Ductless enclosures within their limits. Filtered ductless enclosures need no duct and suit a known, limited chemical inventory within the filter medium's capability, with a monitored change regime. They are unsuitable for unknown, varied or large-volume chemistry, and this limit is frequently exceeded in practice.
5. Confirm containment as installed. Whatever the type, containment is proven in the room it sits in with the air balance it will actually run under, not in the manufacturer's test rig. Establish who tests it, when, and what happens on a failure.

The combinations that need care

Volatile chemicals inside a recirculating biosafety cabinet return to the room, and radionuclides and perchloric acid need specific liners and wash-down arrangements. Where chemistry and biology are combined, the enclosure has to be chosen for both and the answer is often a ducted cabinet.

If nobody can say confidently which enclosure a combined hazard needs, that is the moment to ask a safety professional rather than to order the nearest equivalent.

Living with the choice

Sash discipline, keeping the working area clear of clutter, working well inside the enclosure and not treating it as storage are what make any of these work. The most expensive enclosure used badly performs worse than a modest one used well.

Keep the test certificate visible on the enclosure with its date. Anyone about to work in it should be able to see when it was last proven to contain anything.

Common questions

What is the difference between a chemical fume hood and a biosafety cabinet?

A fume hood draws chemical vapour away from the user and exhausts it outside, offering no product protection. A biosafety cabinet uses filtered air to protect the user, the work or both, and most recirculate, which makes them unsuitable for volatile chemistry unless ducted.

Can I use a laminar flow hood for chemicals?

No. A laminar flow hood blows filtered air across the work and toward the operator and exhausts into the room. It protects the work only and offers the user no protection whatsoever.

Are ductless fume hoods acceptable?

Within a known and limited chemical inventory that the filter medium retains, with a monitored change regime, yes. They are not suitable for unknown, varied or large-volume chemistry.

Who decides which enclosure we need?

The hazard assessment does, and where chemical and biological hazards combine it is worth asking a safety professional. This is the equipment decision with the largest consequences if it is wrong.

Browse by service class

• Compare Gene synthesis on advertised prices