Fume cupboards prevent exposure to hazardous substances in laboratories – provided that they’re correctly maintained. Safety and maintenance of fume cupboards are incredibly important and needs to be fully observed at all times.
Here, we offer our guide to fume cupboard safety and maintenance.
- What is a fume cupboard?
- How should a fume cupboard be correctly used?
- How to properly maintain a fume cupboard
- Legal requirements and legislation for fume cupboard maintenance
In laboratories, fume cupboards are the primary method of controlling exposure to toxic, offensive or flammable vapours, gases and aerosols. A type of local exhaust ventilation system, fume cupboards typically consist of a cabinet, or hood, with a moveable front sash or window, made out of safety glass.
They rely on extraction, which is sometimes controlled by the building’s air conditioning and heating system; fumes are drawn into the hood and expelled through a neutralisation filter. In order to keep protection levels high, fume cupboards have to be used effectively and maintained appropriately. Therefore, the airflow within the fume cupboard needs to be enough to control the airborne contaminants effectively, with factors such as design, size of the window opening, type of process and the substance(s) being controlled all affecting the airflow of the cupboard.
When installing the fume cupboard, avoid placing it next to any windows, doors and walkways, as these can interfere with the ventilation system. Doing so will help to stop airborne contaminants from spreading around the laboratory.
It is vital that fume cupboards are used only for experimental work. A fume cupboard should never be used as a storage cupboard for pieces of science equipment; filling the cupboard can compromise the airflow and increase the chances of harmful substances leaking into the laboratory. The presence of stored chemicals in the cupboard could also increase the chance of further damage if an accident were to occur.
Likewise, it is important to avoid unnecessary clutter such as safety screens, ovens and trays. Again, this will cause turbulence in the air drawn across the base of the cupboard. The effect of turbulence can be reduced by raising all large objects off the base of the cupboard by placing them on blocks. As a rough guide, all pieces of equipment should be placed at least 150mm from the front of the glass.
When doing work in the fume cupboard, take care to ensure that all materials are kept inside the hood at least 150mm from the window opening. The sash opening must be as small as possible to minimise the chance of any fumes escaping. When not in use, always remember to close the sash. When you’re finished, remove the chemicals and store them safely away from the fume hood.
Do not set up equipment close to the front edge of the fume cupboard – as this can increase the likelihood of creating turbulent airflow with the stream being drawn towards the front of the cupboard. As a rough guide, all pieces of equipment should be placed at least 150mm from the front of the glass.
It’s also important to avoid rapid movements in front of the fume cupboard and within the installation. Again, this can disrupt and disturb the airflow – potentially allowing harmful substances to escape.
Furthermore, fume cupboards are not designed for work with micro-organisms. This work and research should be reserved for use with microbiological safety cabinets.
Be sure to include instructions on how to deal with the fume hood in case of fire or power failure when you’re writing an emergency action plan. During power cuts or blackouts, it’s important to close the sash on the fume cupboard immediately and then evacuate the building. Without power, the fan system will not work properly so the fume hood will not have sufficient ventilation.
It is a legal requirement that all fume cupboards should be maintained and tested at least once every 14 months in accordance with the British Standard. Records of inspections and maintenance must be kept on file, alongside certificates provided by maintenance contractors.
A fume cupboard which is not inspected on schedule, or fails the inspection, will be immediately taken out of use.
Over the course of an inspection, the contractors will complete the following checks and tests:
- Check the conditions of the services to the fume cupboard and test the functioning of any alarms and all controls
- Complete a face velocity test
- Check the condition of the fan
- Check the ducts work, and clean where necessary
- Ensure the make-up air pumped into the laboratory is of a satisfactory standard.
The face velocities (the speed at which air is drawn through the front) of the fume cupboards must also be clearly marked on the exterior of the cupboard.
There are a number of pieces of legislation which relate to the use of laboratory fume cupboards, including the following:
This act explains that it is a legal requirement to ensure the systems of work are safe, providing no risks to health. It states that full training, instruction and information to ensure health and safety must be provided, and that all potential risks are removed.
These regulations have been stated as a control measure to prevent exposure to hazardous substances. As such, controlling the exposure to such substances within acceptable limits is a legal requirement.
Suitable and sufficient risk assessments must be completed prior to work activity being undertaken, and all subsequent arrangements must be made.
All pieces of work equipment, including fume cupboards, must be maintained to a safe working standard. Sufficient protection must be given to all users of the fume cupboards.
It is vital that all electronics within, and supporting, the fume cupboard are regularly checked and maintained to ensure nothing has corroded.
If your lab needs redesigning to improve safety and practicality, the team at InterFocus may be able to help. For more information about our bespoke fitted labs, visit our homepage or call our team on 01223 894 833.