Best practices for using and maintaining ‘Biological Safety Cabinets’ in the lab

For microbiologists or labs conducting research on biohazardous materials and pathogens like some bacteria, viruses, and fungi, avoiding contamination is critical. This includes ensuring lab technicians are not exposed to harmful material and preserving sample integrity.

Often, labs rely on biological safety cabinets (BSCs) for this kind of research. A BSC is an enclosed, ventilated, negative-pressure laboratory workspace that allows for the safe handling of infectious or harmful samples.

BSCs rely on a careful balance of inflow and downflow air velocities

In order to keep both lab technicians and samples well-protected, Class II BSCs rely on a careful balance of air and properly functioning filters.

Compromised airflow or filtration can result in possible harm to the lab technician and sample. It’s critical to quickly respond to any issues with your BSC to ensure your lab technicians and samples are safe.

The risks of working with BSCs

There are several risks that come with working with BSCs, including physical harm to the technicians doing the research and contamination of vital samples.

The airflow in a BSC is essential to reducing the potential for injury to the technician working in the BSC, as well as risks to sample integrity and contamination.

To properly function, BSCs rely on a careful balance of inflow and downflow air velocities, and changes in these can result in sample contamination or exposure to biohazardous materials.

In a correctly functioning BSC, air from the lab is drawn into the BSC and creates a protective barrier, preventing any biohazardous materials from the samples being studied inside the BSC from reaching the lab technician.

Lab workers can be at risk of developing musculoskeletal disorders like carpal tunnel syndrome

This air is then filtered through high-efficiency particulate air (HEPA) filters, where most of it is recirculated within the BSC, which minimises the risks of samples being contaminated by anything in the laboratory air. Finally, the remaining filtered air is expelled from the BSC.

If there is any shift in airflow, lab technicians may be exposed to biohazardous materials or pathogens, and precious samples may be contaminated, which can harm technicians’ health and potentially lead to costly delays in research from sample contamination.

Additionally, due to the lengthy and often repetitive nature of work with BSCs, lab workers can also be at risk of developing musculoskeletal disorders like carpal tunnel syndrome, chronic neck or back pain and tendonitis. 

What type of BSC do you need?

Several kinds of BSCs are available, and the right BSC for your lab will depend upon the type of research being conducted.

For example, research into pathogens that can cause severe or fatal diseases in humans will require a BSC and laboratory that can provide extremely high levels of protection.

Research in more common laboratories may not require the most stringent precautions due to the potentially less harmful materials being studied, though it will still need to protect samples and technicians. 

There are also important considerations to take into account when it comes to the BSC’s monitoring and alert systems, since issues with the BSC may have the potential to result in contamination and exposure.

Some BSCs, especially older models, include pressure gauges while more modern cabinets may monitor the rpm and torque of the fan, or have thermal anemometers to measure air speed as ways to monitor for any issues in airflow. While these systems can all help flag specific problems, they are often hard to interpret, provide little insight into airflow specifications, or only measure air speed at a single point. Instead, looking for BSCs that include pressure sensor-based independent airflow monitoring can be helpful.

Some BSCs, especially older models, include pressure gauges while more modern cabinets may monitor the rpm and torque of the fan

These sensors measure pressure change across the downflow and exhaust HEPA filters, helping ensure accurate overall volumetric measurement of both airflows. If there are any variations, these monitoring systems should also provide audible and visual alarms to quickly signal issues.

To avoid other physical challenges that come with repetitive work in a BSC, getting a BSC with adjustable stools and footrests or even electronic stands that can accommodate different heights can also help keep all lab technicians comfortable while working in a BSC and limit the risk of developing a musculoskeletal disorder.

By keeping advanced monitoring systems and ergonomic features in mind, along with the hazardousness of your samples, when selecting a BSC, you can help ensure samples and technicians are better protected. 

Protecting your samples—and yourself

Once you’ve selected the right BSC for your lab, it’s essential to take steps to ensure it is functioning correctly. BSC maintenance is critical in providing a sterile environment.

An unclean or contaminated BSC environment can negatively impact your research by contaminating samples. Because the airflow, which is crucial to keeping the BSC sterile, is invisible, contamination will be hard to detect until downstream applications.

This can lead to delays in timelines and increase the need to do multiple experiments over again. BSC maintenance includes keeping your BSC clean while operating and working with your supplier to receive service and preventative maintenance on your BSC at the right times. 

There are several tips for keeping your BSC clean and well-maintained.

There are several tips for keeping your BSC clean and well-maintained

The first tip is to set yourself up well before starting work inside a BSC. One recommended way to set up is by working “from clean to dirty”.

This means if you’re right-handed, you should have clean materials on your left side of the BSC, your work area in front of you, and waste on your right side.

That way, your waste materials and clean materials will remain separated. Also, you should avoid repeatedly going in and out of the BSC by ensuring you have ready all the materials you need. Frequently going in and out of the BSC will result in additional air being pushed into the BSC with your arms as you go in and out, increasing the risk of contamination.

The second tip is to ensure you’re cleaning your BSC properly. After each use, decontaminate your work surface from top to bottom and back to front with the appropriate cleaner, like 70% ethanol. While you don’t need to clean underneath your work surface after each use, you should clean it regularly to avoid contamination.

If you’re right-handed, you should have clean materials on your left side of the BSC

Finally, the third tip is to stay current with your certification and maintenance. Certifiers should inspect your BSC on a regular basis.

Often, BSCs have stickers on them that will tell you when the next certification should happen. In general, annual certification to test airflow velocity, HEPA filter integrity, airflow patterns and site installation should help you keep your BSC functioning well.

Practicing these steps can help keep your BSC clean and well-functioning—keeping both your samples and technicians safe.

Protecting lab technicians and samples is essential to personal protection and advancing our understanding of pathogens and other biohazardous samples. BSCs can help provide a sterile and contained environment to conduct this research, but they aren’t without risks.

Issues with the airflow or filtration system can increase the risk of sample contamination or technician injury. However, by selecting the right BSC for your work and properly using and caring for it, you can help minimise some of the risks associated with biological research.