Part 4 – BSC selection, placement and summary

How do you know what type of biosafety cabinet to buy? This should be based upon your risk assessment. The assessment should be based on the type of organisms that are being handled, the manipulations that are required, the procedures that are being done by the laboratory, and the size of the equipment that you need for the work. If you use a lot of toxic chemicals or radio nucleotides with your pathogens, then maybe you need a B or C type cabinet. There’s a lot of factors that go into deciding what kind of biosafety cabinet you need. Although in most cases 95% of your needs are going to be met with a Type II A2 cabinet with a canopy connection. 

In order to help you make a BSC selection the Baker company has developed a decision tree (click the link). The decision tree guides you through some decisions and questions you should answer to decide what kind of biosafety cabinet you need. However, make sure you do your risk assessment first and then use this decision tree or selection guide.
Another important factor about using your biosafety cabinet is where do to put it in the laboratory. You want to locate the biosafety cabinet away from any strong sources of air flow, such as doors, windows, human traffic areas and supply air ducts, since the BSC containment airflow curtain at the opening can be compromised. You should locate the BSCs at the back of the laboratory and in one corner, because it’s away from doors, high traffic areas and supply ducts. Be sure to leave adequate space around the cabinet for testing, repair, and certification. You can get further information by looking at the US guidance from the National Institutes for Health (click the link). 

Now to summarize. There are three main types of hoods – biosafety cabinet, clean bench and the fume or chemical cabinet. Know which one does what and use the right cabinet for the right purpose. There are also three types of biosafety cabinets – type I, II and III. Within the class II cabinets there are five different types – the A, B and C cabinets. Remember, they are all slightly different and therefore, depending on your risks, you will have to decide which one to buy. Most likely the class II A2 BSC will meet most your needs. All of these cabinets (unless you specify otherwise) will have HEPA filters that remove 99.97% of particles at 0.3 microns. Particles smaller or larger will be removed with greater efficiency through the methods of interception, impaction and diffusion.
Thank you again for taking this module on ventilated enclosures. Please take the quiz to help you remember some of the things we talked about.