Part 2 – Enhanced laboratory design features (BSL2/CL2)

Now, let’s explore the next level of biocontainment, which is considered containment level or biosafety level II. This level is a step up from the basic biosafety level one. Additional facility features are required to mitigate biorisk, as identified during the risk assessment. The World Health Organization (WHO) refers to these features as “heightened control measures”. Let’s delve into some of the key features that are typically found in a basic biosafety level II facility.
Given the increased risk at this level, the facility should be situated away from high-traffic areas, such as at the end of a hallway or behind double doors. Storage space outside the lab for personal items and street clothing is essential. It is crucial that no personal items, including cellphones and music players, are brought into the laboratory. At this level of risk, eating or drinking inside the laboratory is strictly prohibited. Therefore, it is imperative to have a designated area outside the laboratory where individuals can rest, hydrate, and eat.

It is highly recommended that the laboratory be equipped with a biosafety cabinet due to the higher risk work being conducted, which may result in the generation of aerosols. Biosafety cabinets should be readily available and utilized as necessary. When designing facilities, it is essential to allocate sufficient space for a biosafety cabinet, ensuring there is ample room around the cabinet for certification purposes.

In the design of new laboratories, careful consideration should be given to implementing inward, directional airflow. Ventilation systems should ideally be designed to direct airflow from the entrance of the laboratory towards the back, where higher risk work is typically performed, and then extracted through a ducted ventilation system. It is crucial to prevent the movement of laboratory air into non-laboratory areas. Exhaust air should be directed outside and away from individuals to minimize exposure to potential hazards.

Given the heightened risk, it is imperative to ensure that fresh air is continuously drawn into the laboratory to dilute any potential aerosols of chemicals or pathogens. Windows should remain closed or be non-operable to maintain a controlled environment. Adequate electrical supply, emergency lighting, and consideration for a standby generator are essential to ensure uninterrupted laboratory operations.

Doors within the laboratory should have the appropriate fire rating and be self-closing to prevent being left open inadvertently. Access to the laboratory must be further restricted, and increased signage indicating the presence of biohazards and the additional required personal protective equipment (PPE) should be prominently displayed.
In biosafety level II laboratories, the use of higher risk pathogens necessitates their prompt destruction. Therefore, autoclaves are essential, either within the laboratory, on the same floor, or within the building. While larger, centralized autoclaves that serve multiple laboratories are more cost-effective, they require safe transport and may result in a loss of control over materials. It is crucial to destroy pathogens at the point of use, with the level of risk determining the urgency of disposal.

At this elevated level of work, additional personal protective equipment (PPE) is required, leading to the need for more storage and changing space. For instance, at an enhanced BSL2, shoe changes or shoe covers may be necessary. Adequate space, such as a bench or chair, is essential for safely changing shoes or putting on shoe covers. In some cases, a respirator may be required, which may require storage at the end of the workday. Therefore, support spaces for using additional PPE must be integrated into the laboratory design.
Here is an animated cartoon of a typical BSL2 facility. Features now include, enhanced signage at the door, restricted access, presence of a biosafety cabinet, additional protective clothing, enhanced surfaces, directional inward airflow, and improved equipment labelling. The presence of a chemical storage cabinet and a fume hood further enhances safety measures. It is crucial to consider the location and design of these elements within the facility to ensure a safe and efficient working environment.

In review, it is evident that higher risk work necessitates the implementation of more advanced facility design features. For the majority of clinical research and diagnostic facilities, a basic biosafety level II (BSL2) designed laboratory is deemed appropriate. A BSL2 laboratory encompasses all the design elements of a BSL1 facility, with the addition of enhanced security and safety features, as discussed.

Work involving modified or enhanced risk group 2 pathogens and some risk group 3 pathogens could be conducted within a BSL2 designed laboratory, incorporating BSL3 practices, and safety equipment for added precaution.