Cabinet Selector
Quick reference guide to cabinet types
The following notes are designed as a guide to the different types of cabinets used in laboratories, pharmacies, universities or industry.
They may be used as a guide, to help choose the type of cabinet best suited to the work being undertaken.
It must be stressed however that advice as to the final choice of cabinet should be sought from your Health and Safety Officer and a specialist supplier
Cabinet types
Laminar flow cabinets
Laminar, this term means "a straight uninterrupted airflow".
Laminar flow cabinets are generally used where protection is required for the work or product i.e. in a pharmacy, or occasionally plate pouring.
They come in two types: -
Horizontal - Here the main HEPA filter is placed immediately behind the working area, 'clean' air is blown across the work surface towards the operator - horizontal laminar flow workstation
Vertical - Here the main HEPA filter is placed immediately above the working area, 'clean' air is blown vertically down over the work surface - vertical laminar flow workstation
NB Laminar flow cabinets are primarily designed to protect the work or product and offer no operator protection.
Some vertical laminar flow cabinets offer a degree of operator protection; these are not biological safety cabinets and should be chosen with care and advice from your safety officer.
Astec Microflow can provide both vertical and horizontal cabinets.
Biological safety cabinets
There are three types of biological safety cabinets. Choosing a cabinet should be done in conjunction with the A.C.D.P. Guidelines to assess the hazard levels of material being used, your Safety Officer and a recognized manufacturer.
Advisory Committee on Dangerous Pathogens (A.C.D.P) published by HSE
All hazardous material handled in a laboratory is categorized to give a hazard value; the A.C.D.P has four hazard levels 1 - 4. Before choosing a Biological Safety Cabinet the material to be handled must be placed in a category (1 -4) as this affects the type of cabinet used. See below.
Definitions of Hazard Groups
For the purposes of these definitions, 'disease' refers to disease caused by infection.
| Group 1 | A biological agent unlikely to cause human disease |
|---|---|
| Group 2 | A biological agent that can cause human disease & maybe hazardous to employees; It is unlikely to spread to the community and there is usually effective prophylaxis or effective treatment available |
| Group 3 | A biological agent that can cause severe human disease and presents a serious hazard to employees; it may present a risk of spreading to the community, but there is usually effective prophylaxis or treatment available |
| Group 4 | A biological agent that causes severe human disease and is a serious hazard to employees; it is likely to spread to the community and there is usually no effective prophylaxis or treatment available |
Microflow supply Class I , Class II , and Class III/I biological safety cabinets.
Fume cupboards
Fume cupboards are designed to protect the operator usually from a chemical fume hazard, but can be used where dust is also a hazard.
Control of Substances Hazardous to Health (COSHH)
COSHH lays down guidelines on when protection against a chemical or particulate (dust) is required but not on which type of cupboard to use.
Ducted Fume Cupboards
Historically, fume cupboards have drawn air through a front opening, the air then exhausted directly to atmosphere via an exhaust duct and fan. They are simple to use, straightforward, but can prove costly, as exhaust ducts must run to a high level plus an exhaust stack. Pre-heated or cooled air is also lost so careful consideration is needed prior to installation.
Filtration or recirculating fume cupboards
The filtration fume cupboard operates in the same way as a ducted version and offers the same level of operator protection.
Exhaust air is however filtered and returned to the laboratory via a charcoal filter and not exhausted to atmosphere as in a ducted fume cupboard.
Filtration or recirculating fume cupboards offer more flexibility not being restricted by permanent ducting. However care must be taken to select the correct type of charcoal, or mix of charcoal if a variety of chemicals are being used. Regular testing must be carried out to enable carbon filter life to be estimated. It is therefore very important that advice be obtained from a specialist/safety advisor before a final decision is made on both type of filter used and testing.
Summary
Before choosing a cabinet you should assess the level of risk, decide the conditions you require from the cabinet i.e. is the risk simply chemical or is there a biological hazard, are clean working conditions required?
Sitting within the workplace must also be considered carefully. If unsure on any points seek advice from your Safety Officer or Bioquell. You should then be in a position to approach a company such as Bioquell for costing and details on your chosen cabinet.
Installation of safety cabinets
Sitting and testing of biological safety cabinets is very important, details can be found in B55726:2000. Advice is best sought from a recognized supplier or your Safety Officer, as no two installations are the same. Class I and II biological safety cabinets must be KI tested to prove full compliance with BS EN 12469:2000 on completion of commissioning.
Installation of fume cupboards
Ducted or filtration fume cupboards must comply with the positioning and installation requirements of B57258 part 2 : 1990.
Astec Microflow have a presentation available which outlines how to select the most relevant cabinet for your application - contact us today for more information
