Getting the most out of your biosafety cabinet: top tips for best practice

A biosafety cabinet (BSC) serves as a vital piece of equipment in biology laboratories, providing a controlled environment for the safe handling of hazardous or infectious materials. They operate on the principles of containment, airflow and filtration to protect the operators and the surrounding environment from potential biohazards. High class BSCs can also help to maintain the quality of materials by filtering both the inflow and exhaust air, aiding aseptic processes. 

The design and functionality of BSCs can vary from simple to custom-built designs, with different classes, sizes and features tailored to specific applications. Selecting the most appropriate BSC for your research, and adopting the best practices for its use, are critical to ensure safe and effective

Key considerations when choosing a BSC 

There is a lot to consider when making purchasing decisions for BSCs, from selecting the correct class and design of cabinet for your application to finding a servicing company that works for you. Several of these specifications may be dependent on personal preference, such as aesthetics, but most of them will impact the safety and efficacy of working procedures, and may even be governed by regulations, so should be evaluated thoroughly with a risk assessment. In this section, we will run through key considerations for choosing a BSC. 

Class of BSC 

There are three classes of BSCs that differ in design, airflow and level of safety. The class that you choose will depend on the hazard posed by the biomaterials being used, and your intended objectives.1 The World Health Organization characterises agents into four different risk groups or biosafety levels (BSLs): 

1 – Low or no risk: a microorganism that is unlikely to cause human or animal disease. 

2 – Moderate individual and low community risk: a pathogen that can cause human or animal disease, but is unlikely to be a serious hazard. Effective treatment and preventative measures are available. 

3 – High individual and low community risk: pathogen that usually causes serious human or animal disease, but does not ordinarily spread from one infected individual to another. Effective treatment and preventive measures are available. 

4 – High individual and community risk: a pathogen that usually causes serious human or animal disease, and that can be readily transmitted from one individual to another. Effective treatment and preventive measures are not usually available. 

The BSL categorisation of your microorganism will determine the level of protection that is required for the researcher, environment and materials, guiding your selection of BSC class (Table 1).   *HEPA filter = high efficiency particulate absorbing filter 

Figure 2. The direction of airflow in BSCs. (A) Class I – air flows inwards from the front and out through HEPA filters at the top. (B) Class II – Air flows inwards from the front and downwards through a HEPA filter, creating a laminar flow. (C) Air flows downward through HEPA filters and is ducted out. 

Air extraction 

The class of BSC can be further characterised by whether air is recirculated or ducted out of the building. The option that you choose will depend on the severity of risk to the environment and laboratory personnel from the contaminated air according to the BSL. It is important to remember that HEPA filters only extract particles, they do not remove vapours or gases, so these will not be filtered out of the air. 

Air flow monitoring 

It is beneficial to select a BSC that alerts you if the airflow falls below acceptable levels. 

Certifications and sizing 

Ensure that the BSC meets relevant international standards and certifications, such as NSF/ANSI 49 in the US or EN 12469 in Europe. 

Sizing 

As with any piece of laboratory equipment, the size of a BSC should be an important consideration to ensure that you strike the right balance between providing sufficient working space and optimising valuable lab space. BSCs can vary massively in size, from a couple of metres for multiple users to smaller single-user designs. Manufacturers may even build bespoke cabinets, depending on quantity, sizing requirements and capabilities. 

The aperture 

There are also various types of front aperture openings that may vary on the class of BSC or the style. For example, class I BSCs often have a sash opening, while class III have heavy-duty rubber glove apertures to protect the operator. Openings may be manually or electronically controlled, depending on the user’s preference.  

Ease of cleaning and decontamination 

BSCs should have features that enable easy cleaning and decontamination, such as removable grills and easy-to-reach surfaces. Careful consideration must be given to where removable features – such as night doors – are stored while not in use, to prevent contamination on these surfaces.  

Ergonomics 

Researchers can work in a BSC for extended periods of times, so regard should be given to their comfort to avoid injury or overexertion. BSCs with arm rests, extended access openings and sloped viewing windows or side windows can offer enhanced ergonomics.  

Additional features 

There are various other features to consider – such as the number of power sockets – that can improve the ease of work. Custom-built instruments can be designed to your specific requirements, but are often more expensive and less adaptable to different applications.  

Service and support 

Work with a reputable manufacturer that provides installation and training, and excels in customer support, warranties and service contracts.  

Best practices for operating a BSC 

Adopting best practices for BSCs is essential for several reasons, all of which contribute to maintaining a safe and controlled laboratory environment. This is critical for:  

• ensuring the safety of the personnel operating the BSC;  

• the containment of biohazardous materials;  

• sample integrity by reducing the risk of contamination;  

• compliance to regulations;  

• and minimal equipment downtime through regular maintenance. 

In this section, we will offer guidance on the best practices for operating a BSC. 

Proper and appropriate training 

Ensure that all personnel using the BSC are adequately trained in its operation, and understand the manufacturers specifications. Operators should also be aware of the protocols for the materials being handled. 

Personal protective equipment (PPE) 

Always wear appropriate PPE, including a freshly laundered lab coat, gloves and safety googles if required. Gloves should be frequently sterilised and changed, as disinfectants can break down the material. 

Aseptic technique 

Adopt aseptic working techniques to prevent contamination of materials and maintain optimal safety. 

Guidance for aseptic technique 

• Prepare the work surfaces by sterilising them before and after use with a disinfectant with proven efficacy against the target pathogen. This cleaning should be thorough, and include wiping underneath the base plate, where dust, fibres and spilled media may gather.  

• Sterilise all equipment that will be used in the cabinet, including water baths, pipettes and flasks. 

• Wear a freshly laundered lab coat, and disinfect and replace gloves frequently. 

• Leave the cabinet running for a few minutes before beginning work. During this time, air will circulate through the HEPA filters, drawing out any airborne microbes. 

• Adopt best practices for pipetting and mixing to avoid wetting the collar of a flask. If the collar of a flask is wet, this can encourage particles to stick to the surface. 

• Hold pipettes facing downwards to limit the surface area that contaminants can land on 

• Limit the amount of equipment in the BSC, as this can disrupt air flow. Avoid using paperwork in the cabinet, and remove any waste. 

• Where possible, designate ‘clean’, ‘working’ and ‘contaminated’ areas in the cabinet (Figure 4) 

Proper cabinet placement 

BSCs should be placed in an area with minimal disturbance from other personnel or airflows, and a ‘safety zone’ should be established behind the operator. Maintain proper spacing between the cabinet and other laboratory surfaces, including opposing and adjacent walls, as well as lab benches. BSCs should be placed away from disturbances that can impact the integrity of airflow, including: 

• Draughts 

• Air conditioning units, fans or air inlets 

• Doors 

• Through traffic 

• Open windows 

Appropriate operator positioning 

Limit movement in and out of the BSC during operation, and always place hands in a position that ensures a smooth and laminar airflow. Always avoid blocking the front grille, and do not sit with your skin or eyes exposed to any liquids that you are working with, to shield you from splashes. BSCs will protect operators from aerosols, but do not prevent splashes. 

Regular maintenance 

Follow a regular maintenance schedule for the BSC – including certification, filter replacement, and any other manufacturer-recommended procedures – and ensure that all repairs are performed by a qualified technician. BSC cabinets should be fumigated every 6-12 months. It is critical to service and safety test class I-II BSCs annually, and class III cabinets more frequently, depending on the institutions own risk assessment. Cabinets are tested in situ, so changing anything in their physical makeup or relocating the cabinets will require retesting. Keep accurate records of BSC certification, maintenance and any incidents. 

Follow regulatory guidelines 

Adhere to all relevant biosafety guidelines and regulations established by the appropriate regulatory body.  

Summary 

BSCs are essential to maintain the safety of personnel and the environment in biology laboratories when working with biohazardous materials. By selecting the appropriate class and design of BSC, and using proper techniques, you can ensure these cabinets will work to protect yourself, your colleagues and even your work from contamination and hazards. 

Contact us to discuss how Haier Biomedical’s BSCs could support your laboratory. 

sales@haierbiomedical.co.uk or call 01932 780 070.

View our BSC portfolio here: https://www.haierbiomedical.co.uk/biological-safety-cabinet 

References 

• WHO publishes latest manual on biosafety in laboratories. (2020). World Health Organization. Accessed 15th November 2023. https://www.who.int/news/item/14-01-2021-who-publishes-latest-manual-on-biosafety-in-laboratories. 

• Laboratory biosafety manual, 4th edition: Biological safety cabinets and other primary containment devices. (2020). World Health Organization. Accessed 15th November 2023. Laboratory biosafety manual, 4th edition: Biological safety cabinets and other primary containment devices (who.int).  

Information from Doug King, Manager of the Cruciform Teaching Facilities Unit, University College London