Renovating existing research facilities to include BSL-3/ABSL-3 space is a growing trend, as more organizations investigate emerging infectious diseases in the wake of the COVID-19 pandemic. Adding these high-containment spaces to existing buildings is expensive and challenging, and requires the utmost attention to safety and security.
Special consideration must be given to the type of research being conducted now and how it might evolve in the future; the location of the labs and ancillary support spaces; security; HVAC airflow and filtration; breach-proof containment barriers with carefully selected doors and construction materials; ductwork placement; impact of the renovation on current building occupants; equipment selection; lab services and proximity to support functions; logistics for moving equipment and animals; equipment maintenance; workflow processes; and waste disposal.
“Most of our renovation projects are 2,000 to 5,000 sf, and the cost per square foot can be surprisingly high,” says Matthew Hart, science planner at Flad Architects. “You have to take new ductwork away from the space, get new ductwork to the space, and deal with drainage issues, not to mention other issues that can exacerbate the challenges and increase the costs, particularly within a facility that is continuing operations in the neighboring spaces.”
Ross Ferries, senior lab planner at Flad, notes one relatively invisible cost associated with BSL-3 labs: The controls that modulate the mechanical supply and exhaust air systems that maintain the proper directional airflow into the labs. While the physical materials are not expensive, the design, integration, and commissioning of these systems are.
Importance of Location
Finding a location conducive to providing top-notch security, safety, and access by the appropriate individuals begins by communicating with researchers and other stakeholders to determine their needs, and conducting a thorough assessment of the existing building.
The design and size of BSL-3/ABSL-3 facilities vary, depending on the configuration, size, and mechanical resources in the existing building. The facilities typically include labs, animal holding rooms, procedure spaces, shared equipment, sterilizers or autoclaves, changing rooms for gowning in and out (don’t underestimate the amount of space needed for this), and an airlock for moving equipment and materials.
The BSL-3 suite should be located near critical ancillary functions, such as supporting BSL-2 labs, cage wash areas, planning spaces, and science offices. In addition, there should be a readily accessible and secure path for animal movement and waste disposal.
Proximity to related functions is also important, versus a café or other heavy-traffic spaces, and should be secured in behind-the-scenes locations with preferably three layers of security, especially if the research involves select agents. The first layer of security is the site itself; the second is the high-level clearance access to enter the facility; and additional security measures—the third layer—are necessary to protect the work occurring in the lab/vivarium zone.
“Institutions have differing approaches to security devices, such as surveillance cameras and all manner of access control devices on the lab’s entry doors,” says Ferries. “However, choosing a location that is already secured or can be secured from public areas is profoundly important.”
The depth and geometry of the location also matter. Depth is important to enable the easy and comfortable flow of people and equipment. For example, a 25-foot-deep space could be challenging. When you remove space for a change area or an access corridor to move people in and waste out, the space left for lab equipment might be insufficient.
Geometry—how a space is configured—is an essential consideration when selecting a location. A rectangular area without nearby obstacles works better, for instance, than a space that wraps around stairs or is near an elevator. Depth and geometry are important for the easy ingress and egress of large equipment, such as autoclaves, cage racks, and biosafety cabinets.
“Make sure there is proper space in the corridors and within the facility itself to move, maintain, and clean these pieces of equipment,” advises Hart. “There also must be plentiful space above the BSL-3 suite to house mechanical and plumbing systems, if possible, and it’s helpful if there is room below for drains and under-slab or under-floor utilities.”
Containment Guidelines and Protocols
Mark Corey, a principal at Flad, emphasizes that select agent work often comes with additional security and biocontainment requirements, making it critical to build flexibility into the design, even if the initial plan does not include select agents. While all BSL-3 labs require layers of security and multiple doors to gain access to individual labs, ensuring there is future capability to add access control devices is necessary to ensure enhanced security for a select agent lab.
“If you’re thinking about using select agents, let the design team know early on,” says Corey. “Even if it’s not going to happen for a few years, we can plan for it to happen later. These facilities are so complicated that it is very difficult at the end to do a retrofit from a design or construction standpoint.”
Many BSL-3 labs incorporate plumbing for showers at the lab’s entry, even if the spaces are simple pass-through areas when the lab first opens. Some select agent work may require those exiting the lab to shower.
“Select agent work may also require the treatment of the effluent from the lab,” notes Corey. “Ensuring there is adequate space below the lab to add a future effluent disposal system is critical for those who may potentially work with agents that require that level of containment. This is usually the most difficult to incorporate if not well-planned into the lab as an initial component.”
The Biosafety in Microbiological and Biomedical Laboratories (BMBL) manual provides guidance on general design features and protocols, and the National Institutes of Health offers design requirements that may be useful. Know which select agents require specific design features, effluent treatment, and enhanced security.
“Talk to the researchers about how they are going to do their work, and how they are going to get materials in and out of the labs,” suggests Corey. “Map out the flow of materials and procedures using a site-wide logistics map on a building scale, and then map it inside the room itself.”
The mapping includes safe protocols following a chain of custody from the security check, sample receipt, sample storage, lab analysis, sterilization, and waste pickup. Make sure everyone is comfortable with the mapping, so additional materials or steps won’t be necessary in the future.
Using diagrams can be helpful to track the safe movement of people throughout the facility, as well as the flow of waste exiting the building. It is critical to have an egress route for people to safely exit the facility in a manner that allows them to remove their personal protective equipment quickly, especially in an emergency.
A sterilizer is recommended to treat the waste before it exits. Flad recommends two sterilizers in case one is undergoing maintenance or not working properly. If there is no second sterilizer, a protocol must be developed to package the material, spray it with disinfectant, then move it to another part of the building where it can be sterilized.
Preventing Barrier Breaches
Establishing the location of the tightly sealed containment barrier and what rooms/spaces are included inside that barrier should be done at the onset of the project with all stakeholders involved in the decision making. Consider the gowning and doffing areas to ensure users are comfortable with the process of knowing what material must be left inside the barrier and when it is safe to exit.
While doors into BSL-3 spaces are usually designed to allow air to flow under or around the door leaf to maintain inward directional airflow, the door frames should be air-tight. The frames should be fully welded with air-tight back boxes behind any holes utilized for attaching hinges or for incorporating locks and access devices.
“Walls and floors of any containment lab should be as monolithic as possible,” says Ferries. Poured epoxy floors are preferrable to tiles, and gypsum ceilings that can be coated in paint or epoxy are preferrable to gasketed ceiling tiles.
The most common areas where containment leaks are detected during commissioning are around any objects that penetrate the barrier—where electrical outlets come through the walls, light fixtures come through the ceiling (if using recessed fixtures), and around pipes or ducts. Ferries recommends spending extra time describing the importance of these areas to the contractors.
Airflow and HEPA Filtration
Directional airflow is important in BSL-3 facilities, where air must move from clean areas toward potentially contaminated areas, then (most often) exit through HEPA filters. Understand the relationship of the BSL-3 airflow and exhaust systems to adjacent space and the remainder of the building where other occupants are working. Flad recommends having a backup plan for any system failure to ensure the safety of all building occupants.
“The biggest challenge of incorporating a BSL-3 into an existing building is usually the HEPA filtration,” says Ferries. “Ideally, we would be able to find a space directly below a mechanical room, but this is actually quite rare, and finding a mechanical room built with additional free space is equally rare.”
It is challenging to locate HEPA filters beside, above, or sometimes inside the lab, and then determine how to get the ductwork out of the building to new redundant exhaust fans, which is yet another reason why the location of the BSL-3 lab within the building is so important.
“Engaging a mechanical engineer familiar with these challenges at the stage of site selection is imperative,” says Corey.
The BMBL does not state that HEPA filtration is required on a BSL-3 lab, but Flad highly recommends filtering any outgoing air due to the type of research, the location of the lab, and neighboring functions. On the other hand, other waste leaving the lab can be treated at the source and decontaminated chemically before sending it down the drain, so an effluent treatment system is not always needed. Analyze the risk of air and liquids leaving the lab, and create a plan for addressing those possibilities.
“The really critical sections of ductwork that need to be kept simple, short, and free of leaks are those between the containment lab and the HEPA filters,” says Ferries. “Keeping the HEPA filters really close to the lab is more important than having the air handling units that supply the air or the exhaust fans close. It’s nice to have everything close to but outside the lab, for ease of design, maintenance, and controls, but if the clean air needs to travel up or down a few floors, that’s fine.”
The HVAC system is one of the most critical design components for a BSL-3 lab. It is imperative to engage a mechanical engineer well versed in the issues surrounding directional airflow, decontamination, shut down, and failure scenarios for these complex labs. While an HVAC system with a supply air handler and exhaust fans dedicated to the new lab may seem like the answer, it is equally critical to understand the whole building’s HVAC system.
“When the BSL-3 lab shuts down and the rest of the building keeps running or vice versa, there is the potential for reversal of airflow,” says Corey. “Knowing how the BSL-3 will operate within the whole system is important to understanding the operations of the systems dedicated to the BSL-3.”
By Tracy Carbasho
