To ensure fume cupboards are in working properly and are in good repair, thorough examination and tests must be carried out at least once every fourteen months. In practice this frequency of testing may be increased in accordance with the risk assessment of the effects of system failure. The information below should help customers identify their type of fume cupboard/s.
When it comes to fume cupboard there are two main types ducted, and recirculating (ductless). Both work with the same objective – to draw air away from the open end of the cupboard and either expel it into the outside environment or pass it through filters and back into the room.
Ductless Fume Cupboards (Recirculating)
Recirculating fume cupboards are self-contained units that draw contaminated air away from the aperture, passing it through a filtration system and discharging it back into the room. The type of filter used is dependent upon the class of the chemicals being worked with and all filters have a maximum absorbency capacity. It is vital to ensure that the limit is not exceeded, as this can result in the release of hazardous substances into the work environment and cause a potential risk to the occupiers of the cleanroom.
Recirculating fume cupboards are not suitable for work involving highly toxic, carcinogenic or sensitising substances or radioactive material. In fact the Health and Safety Executive (HSE) do not recommend using these fume cupboards for exposure control of vapours or carbon nanotubes (HSE Control Guidance note 201 and HSE Risk Management of Carbon Nanotubes 2009).
The selection and installation of recirculating systems must be carefully reviewed. Consideration should be given to whether such a unit can provide adequate, reliable control of the anticipated hazards and that the resources and a safe system of work are in place to ensure the unit is monitored and maintained throughout its life cycle.
Ducted Fume Cupboard
Fume cupboards that are ducted have externally located fan units connected to the fume cupboard via duct work. These fume cupboards generally pull air from their front aperture, through ducts to vent to a safe position on the roof of the building. This point of discharge is usually at least three metres above the roof line, so hazardous fumes can be safely diluted in the atmosphere.
The Two Fume Cupboard Testing Standards
There are two main fume cupboard and LEV testing standards – British Standards BS EN 14175 for industrial ducted systems, and British Standard BS7989:2001 for recirculating or ductless units.
British Standards BS EN 14175 and British Standard BS7989:2001 both specify the safety and performance requirements for general purpose fume cupboards and also outline the technical specifications required for their design, manufacture, installation and containment.
While historically, face velocity measurements have been used to demonstrate fume cupboard performance, current emphasis is on demonstrating containment, which is done by establishing a programme of regular tracer gas containment testing. The test methodologies suitable for fume cupboards are detailed in the British and European standard (BS EN 14175-2:2003), available from the British Standard Institute (BSI).
APT can carry out your Fume Cupboard and LEV Testing
I hope the above information was informative. If you would like some more information in regards to our cleanroom testing service please don’t hesitate to contact Darren directly on 07775623464.
APT Cleanroom Testing provides clients with a reliable and proactive clean room testing service. If you would like to know more about our particulate testing service and/or HEPA filter testing service to cleanrooms, please don’t hesitate to contact us at: email@example.com