This article will explore the differences between a Class II B2 (Ducted) Biosafety cabinet and a Laminar Flow Fume Cupboard. 

Let's first break down how each cabinet manages airflow, which is where confusion can come in.  

Biosafety Cabinet Class II B2

1. Air is drawn through the face of the cabinet, typically at 0.5m/s as standard using an extract fan positioned on the outside of the building. 
2. Room air is then taken under the raised worksurface, up the back of the plenum and through a HEPA H14 filter before being exhausted to the atmosphere. 
3. A secondary fan is used to draw air from the top exterior of the cabinet through a HEPA filter and create a clean laminar flow of air onto the worksurface before being pulled under the work surface and out to the atmosphere through the exhaust HEPA filter.

Laminar Flow Fume Cupboard

The airflow pattern of a laminar flow fume cupboard is the same as a B2 biosafety cabinet.  So what is the difference? 

The main difference is that the extract on a Laminar Flow Fume cupboard is NOT HEPA filtered before being exhausted to the atmosphere.  This means harmful pathogens should not be used inside this cabinet. 

It may seem like the Laminar Flow Fume cupboard is somewhat limited in its uses.  However, it's not as simple as that.

So why might I choose a Laminar Flow Fume Cupboard?  

1. My work involves the use of chemicals that may damage the interior of a typical class II cabinet. 
2. I need flexibility in design and want to avoid the strict BS EN12469 standards.  By using a cabinet designed as a Class II B2 cabinet, we have to conform to the standards set for the design of this cabinet type. 
3. I'm working with applications such as trace metal analysis which require a metal-free work zone and clean air to limit cross-contamination. 
4. I have a general application that requires both the clean air of a laminar flow cabinet and the extraction and safety of a fume cupboard. 

In conclusion, a Class II (A2 or B2) is your choice if you are using pathogens.  If you need a blend of clean laminar airflow and extract for chemical applications, then the Laminar Flow Fume Cupbaord is for you. 

If you need further advice on choosing the right unit for your application don't hesitate to reach out to one of the team