Microbiological safety cabinets or simply called biosafety cabinets are enclosed laboratory workspaces with ventilations. These are often installed in the laboratories to enable the workers to work efficiently with the materials that either contain pathogens or can release toxic gases on reaction. Therefore, these cabinets protect the researchers and/or the staff from inhaling the toxic substances.
Different Kinds of Safety Cabinets
The microbiological safety cabinets are primarily of 3 broad categories:
Class I – These cabinets draw air from the room via the open front, which then passes through the working area. This air is then passed through the high-efficiency particulate air (HEPA) filters. This process helps in removing the infectious particles and is ducted to the outside air. We should be careful to maintain a minimum airflow of 0.7 m/s through the front-side of the cabinet. As soon as the airflow falls below this level we must ensure that we change the filters.
Class II – These cabinets filter air and most of it is recirculated through the cabinet. These cabinets are immensely popular because they protect the worker and his work. Around 70% of the air is recirculated through the filters. This helps in bathing the working area in clean (almost sterile) air. The remaining 30% of air is exhausted back to the atmosphere. The cabinet draws in the same quantity of room air at the working face as soon as it is done with the previous process.
Class III – These kinds of cabinets are completely enclosed and thereby, leak-proof. Here, the operator has to work with his gloves on, which are sealed into the front of the cabinet with removable gaskets.
Apart from these microbiological Incubators cabinets, there is another type of cabinets, which are not precisely microbiological cabinets:
Laminar flow (clean air) cabinets – As the name suggests, these are clean air cabinets and
not microbiological safety cabinets. Here, the air is drawn through HEPA filters, which then passes onto the working surface and the room. Though they don’t share the same usages as the earlier cabinets do, you can easily find them in pharmacies where they are extensively used in the preparation of tissue culture.
The microbiological cabinets work according to the permissible biosafety cabinet
level and are also designed accordingly.
What are Biosafety Levels?
There are 4 biosafety levels we know of:
Biosafety Level 1: This level applies when you work with biological agents that are regarded as imposing the minimum amount of risk to the laboratory personnel and the environment. You can easily use open laboratory cabinets when performing experiments that fall under this category. Besides, you don’t need to use the special containment equipment here.
Biosafety Level 2: This level entitles the laboratory workers to work with pathogenic or infectious organisms that pose a moderate risk. For example, if you are using Salmonellae, Hepatitis B virus, or the Measles virus, you are deemed to be working under this level.
Biosafety Level 3: This level applies when you are working with indigenous or exotic agents that may give rise to serious or lethal disease with the help of aerosol transmission. For example, if you are working with Yellow Fever and Encephalitis, you are working under Level 3 of biosafety.
Biosafety Level 4: This level is the most serious of all because it only applies while you are working with extremely dangerous, contagious, or agents that can claim lives. Maximum containment and protection are required at all times. Some of the examples of these agents include Ebola, the Lassa virus, and any other sample fraught with unprecedented or unknown risks of pathogenicity and transmission.
Installation and other important information
When it comes to the installation of the safety cabinets, you must ensure that it is done carefully and by knowledgeable experts. This is because the sitting of the cabinets is one of the most crucial steps while working with these.
The main problems are caused by the draughts from doors and windows. Furthermore, the movement of people also plays an impact on the installation and thereby, the working of these devices. Therefore, while installing biological cabinets always remember not to install them in close proximity to doors. The HEPA filters, which commonly go by the name high-efficiency particulate air filters are highly efficient in removing the viable microorganisms. They do these extremely efficiently with a commendable rate of 99.997%. Furthermore, you should also keep an eye on the ducted effluents. These should not be discharged while you are near open windows, especially in hospital wards.
Though working with biological safety cabinets sounds safe enough, they also need to be handled properly because always remember that you are working with potentially dangerous/lethal or fatal elements/organisms. Once you follow all the strictures in the installation process of these devices and get it installed by a professional you can easily carry on with your work without a dint of hesitation. Good luck!