A fume cabinet, also known as a fume cupboard, fume closet or a fume hood, is an extraction system used for capturing and removing toxic dust, fumes, aerosol and vapours to minimise exposure to a safe level. It is most commonly found in laboratories, where such substances are handled.
As you may already know, medical and pharmaceutical laboratories work with many chemical agents, powders, solutions, biological dust as well as pathogens. If they become airborne, they can be inhaled by technicians, which can be potentially dangerous for their health.
Even if you don’t consider the health hazards, they can also cause cross-contamination if they mix with other materials in the lab. Either way, it is in the best interest of everyone’s safety to contain them, or at least reduce their concentration in the air, at the source via a fume cupboard.
In the case of liquids, there is also the added danger of spillage. Harmful, toxic or corrosive liquids can pose a threat to people as well as other materials in the room. However, if the spill occurs inside the fume cupboard with a spill tray, it is contained and not a danger to anyone.
It is essential to understand that fume cupboards, unlike bio-safety cabinets, don’t serve as containment units. They merely reduce the exposure by extracting contaminated air away from the technician and the room. Therefore, they are not the right extraction solution for highly toxic or infectious materials.
However, if you need to ensure that chemical dust and vapours don’t affect the health of your technicians, you do need to invest in fume cupboards.
How Does a Fume Cupboard Work?
A fume cupboard is a five-sided box with a window, or opening, in front. This window has a movable panel made of safety glass and the bottom of the box is level with the working surface. This is where the technician can place the material to work with it, whether they need to weigh it or portion it out.
At the top of the cupboard is the fume hood that pulls in air from inside the cupboard. In order to keep the dust or vapours of the material from escaping into the air, the extraction system inside pulls in air from the open front, away from the technician. From that point, where the contaminated air goes depends on whether the fume cupboard is ducted or ductless.
Types of Fume Cupboards
A fume cupboard can be of two types.
Ducted Fume Cupboard
This type of fume cabinet pulls the air from the open front and draws the airborne contaminants inwards, eventually expelling the impure air outside the building.
Ductless Fume Cupboard
As with the ducted fume cabinet, the air is sucked inside. However, instead of being expelled outside, it passes through different types of filters. These remove the dust vapours and fumes before recirculating the clean air back into the room.
Fume cupboards may also be classified according to their uses, as certain substances or processes may require specialised material or construction. However, all of them will be either ducted or ductless.
How to Use a Fume Cupboard Safely
It is crucial to ensure that a fume cupboard is being used appropriately to provide maximum protection. If used carelessly or incorrectly, the extraction system might not be able to remove all of the contaminants from the air.
Before you start using the fume cupboard, make sure it is working properly, and it has enough space inside for the tasks you are about to perform. If there isn’t enough space, you run the risk of knocking over or spilling the materials.
More importantly, it might mean that the fume cabinet might not be able to extract the contaminants effectively. Essentially, you need to ensure the extraction unit is appropriate for the work you are about to undertake.
Pre-start checks may also include checking the filters and making sure they don’t need to be replaced. Fume cupboards use a variety of filters, depending on the use. These may include high-efficiency particulate air (HEPA) filters, Carbon filters, exhaust filters and more.
It is important to note that all of these filters need to be replaced at the right time in order to be effective. How often they should be replaced depends on the type of filter and the frequency of use, so you should check the recommended changing time for each of them. The checks and replacement dates should be recorded in a system logbook to ensure that changing dates are not missed.
Always ensure that you are using the fume cupboard as per the instructions provided. One of the things to check is if the sash height is correct and if you’re using the right equipment. Make sure you are, or the person who is going to use the fume cupboard is, adequately trained to operate it.
Once you’ve finished using it, always clean the inside of the fume cupboard. This will reduce the chances of contaminating the material that is used next. Additionally, it will also prevent the dust or fumes from getting into the room once you turn the fume cabinet off.
A fume cupboard can be a great tool to protect you and others in your laboratory from airborne contaminants if it is used properly. Part of its proper use includes knowing which type of fume cupboard is suitable for your needs.