The post from January 10thon Mobile and Modular Laboratory Platforms generated an interesting question.
The question was,
‘If we can build the BSL-3 lab with local tradecrafts, but do not think there is local experience in HVAC construction and controls, is it possible to purchase the HVAC system in a prefabricated package for delivery and installation’?
Yes, it is possible to purchase a prefabricated HVAC system with controls to support a Biosafety Level-3 lab. It will require coordination between the team working on the lab, to include the architect, engineer, and project manager with the supplier of the HVAC system. The supplier in essence is acting as the mechanical engineer and will need access to drawings and specifications to:
identify penetrations, connections and site survey details,
size the system to accommodate heating and cooling load data,
plan for cascading airflow, sensor and damper placement,
engineer a system that does not conflict with those services in adjacent spaces in the existing building (i.e. building automated system),
harmonize systems when needed (i.e. security control systems, BAS),
coordinate electrical and plumbing connections and specifications, and
coordinate other aspects related to the HVAC and associated systems during facility design to ensure smooth construction, commissioning and acceptance phases.
The HVAC system and its control system (BAS) are the most often cited Achilles heel of containment laboratories. Purchasing a prefabricated HVAC system that meets WHO, CDC or other recognized design recommendations is a very suitable strategy when there is a lack of tradecraft with experience in Biological Safety Level 3 construction, and in cases where the laboratory is in a retrofit space that can not be accommodated/reliably accommodated by the existing building system. It can be significantly less expensive than trying to retrofit an existing building HVAC system and has the added benefit of allowing operations to continue in the existing building during construction of the addition or renovation of the space.
Experience: HVAC for BSL-3 Containment Labs
If an organization does choose to purchase a prefabricated HVAC, it should be one designed and built by companies that can provide proof of construction of several functional BSL-3 containment laboratories . Companies that specialize in clean rooms and have no true expertise in biocontainment typically and catastrophically misapply HVAC and BAS clean room concepts to containment labs. It is important to ensure companies have biocontainment experience similar to your project. Components of HVAC for BSL-3 containment include but are not limited to welded leak tested stainless steel exhaust duct and HEPA housings, HEPA housings with scan test and decontamination ports, airtight dampers for room decontamination, and rapidly responsive air volume control valves and a BAS to prevent sustained pressurization of the lab during HVAC failure.
The goal is to have a working building that provides a safe work environment to staff and the community and can be maintained by personnel on-site. To that end, the company should act as the single source that has responsibility for the systems and subsystems and ensuring once connected to the lab, the system performs per design intent. To every extent within reason the system should be sustainable and serviceable within the region. While specialists may be required to decontaminate and replace HEPA filters within the housings, the system should be designed and constructed such that for example, standard air-conditioning and heating components can be worked on locally. The planning done on the front end of the project, and selecting an experienced containment company will provide huge dividends throughout the construction process and life of the building.