Lastly, the third basket of controls that we talked about is facility design. This is considered secondary or tertiary containment and plays an important role in biorisk management. The facilities must be designed with the underlining intent of providing protection and containment. The facility features must help protect the laboratory workers, the people outside the laboratory and the environment from the biological agents being used in the laboratory. Therefore, the design is important as is the maintenance of the facility and equipment. Let’s now look at a few facilities design features.

First, what is a containment laboratory. You could think of it as layers of open and closed barriers. You can see in the picture the dotted line, which represents the outside of the building. The entrance is mainly closed, but at times it is also open to allow access for people. Within the building you have the laboratory room itself, which is shown as the heavy black line with a door where you enter and exit. It too, is a mostly closed but opens at times to allow the movement of people and materials. Then within the laboratory, we have the biosafety cabinet shown in blue. Unless it is a type III biosafety cabinet, it is both open and closed. It is physically open because you can put your hands inside, but it is also a closed because of the air curtain that forms an air barrier between the inside and outside of the cabinet. Finally, there is the physical containment system in which the pathogen resides. This is a container, which is mainly closed, but you must open occasionally to be able to get the sample. These are all examples of layers of open and closed systems of containment. We sometimes call it the box within a box within a box of containment. Each layer provides a different level of protection and you must understand what each does to provide containment. 

The secondary barriers, in some cases, also protect the environment through extra features such as high efficiency particulate air filters (HEPA) that cleans the air before it leaves the laboratory. We will look at these in more detail in another module. There may also be liquid effluent treatment systems where all the liquid waste coming out of your laboratory’s is decontaminated before it is released to the environment. In some cases, the room itself must sealed so that nothing can leak out, and no air can escape. However, the more engineering controls that are used and the more design features you put into laboratories, the more it costs to build and maintain. So, keep that in mind and do not over design or over build your facilities. The facility design features should be selected based upon a careful risk assessment.

Here is an example of how facility design supports biosafety levels from the World Health Organization. On the far left-hand side you can see the risk groups – risk group, 1, 2, 3 and 4 listed. Again, this is based on the risk of the pathogen that you are working with. However, remember that the inherent risk groups are only a starting place from which the risk is modified by the procedure and the worker. Then you see the biosafety levels, 1, 2, 3 and 4. This table shows a direct correlation between risk group and biosafety level. As you now know, this is not always true because risk groups vary and biosafety levels vary. Biosafety levels are a combination of the three types of controls shown. The laboratory type or facility design, practices and procedures, and safety equipment. Biorisk management is just combining these three types of controls in the right way to give you of the right amount of risk mitigation that you need to operate safely.

Throughout the rest of these lessons, I will be using the term biosafety level or BSLs. However, not everyone in the world talks about the combinations of controls in the same way. Some countries refer to them as containment levels or CLs. Some countries talk about them as protection levels or PLs. Do not get confused when you see other countries talk about containment levels or protection levels – they are talking about the same thing. These terms are all referring to a combination of laboratory practices, techniques, safety equipment and laboratory facilities that come together in the right way to lower the risks that you may be facing in a particular situation. Not to be confused with risk groups.