The team selected holding and procedure rooms as the mock-ups for testing and evaluation because of their role as primary containment rooms. The mock-up room also served as an educational vehicle through which construction and application techniques were mastered. Items selected for testing and evaluation included penetrations, the rapid transfer port for the animal transfer carts, data cables, material transitions, and rooms.

“The workmanship in these areas has to be dead-on. The details have to be executed correctly or they won’t pass a two-inch pressure decay test to which we were required to subject them,” says Zynda.

The pressure decay test is a three-step process that serves as a baseline for workmanship of the room system, not just individual components. The first step is pre-testing for gross leaks by pressurizing the facility to a half-inch water gauge, then looking and listening for major leaks. Leak points are physically marked for repair after each testing phase. The second step is soap bubble pre-testing, which consists of applying a foaming agent to the walls in order to identify additional leaks. The third step is actual pressure decay testing for final certification, in which the room must hold a negative pressurization of a 2-inch water gauge with a degradation of not more that 50 percent over a time period of twenty minutes. This demanding test has been adopted by the University of Pittsburgh’s Environmental Health and Safety Department as its standard, however similar testing principles can be applied to ensure relative tightness in any biocontainment laboratory.

“A lot of the detail elements used in biocontainment aren’t necessarily products or techniques that tradesmen have seen before,” says Zynda. “One of these was high-performance coatings. We had a multi-layer, Tnemic system with a fiber mat that is wet-applied into resin on the wall.

“The fiber mat comes in 4-foot wide sheets. It actually has to be overlapped and then back trimmed so that there is no gap between these sheets,” he continues. “Matching seams is crucial. It took the tradesmen a little bit of time to learn that, but working with the product rep, they got it down.”

Through an educational process, the contractors worked with the vendor in the mock-up room to master the application technique and successfully apply it to the project in its entirety.

Another unfamiliar application technique involved a two-pound, closed cell foam sealant backer that surrounds device boxes through all the penetrations. If there ever was a sealant failure in the rooms themselves, the backer would prevent a breach of containment. A lot of the tradesmen hadn’t worked with the foam sealant before. The original product had to be delivered in a tanker truck, piped up eight floors, and then sprayed on, but it just kept expanding.

“It was the right product for the application, but because of where the overall project was in construction at the time the foam arrived some product adjustments needed to be made,” says Zynda.

By evaluating the project in a collaborative forum, the constructability issues were more clearly understood by the design team and a product substitution that met the original performance requirements was made.

With a multi-function building, primarily composed of non-containment space, the design called for double-wall lab waste piping through the facility. There is a carrier pipe inside and a secondary containment pipe outside. The sections of piping for both the carrier and secondary containment pipe are fused together with an electrical device that carefully measures the time and effectiveness of the process. Each joint is serial numbered and cataloged by location to ensure proper installation. The entire system was subjected to 5-psi pressure testing and then full hydrostatic load testing to ensure that each fused joint was correctly executed.

“A lot of the plumbers had never seen this type of system before. They require specialized construction techniques,” says Elinski. “If these guys just looked at the detail and it went into the field as originally happened, then they wouldn’t have successfully executed this. This required certain training and clearances.”

Cast electrical boxes and gas-tight faceplates were used to seal the electrical device penetrations and ensure barrier integrity. Once the wire is pulled through, the conduit and faceplates must be sealed to prevent a containment breach through the conduit. Then a foam sealant was applied around each device penetration as a secondary means of containment in case of silicone sealant failure or damage.

“It is a basic electrical box, a penetration in a wall,” says Zynda. “On just about any other project other than BSL-3, you wouldn’t even think about it. You put it in the wall, everybody knows what to do, and they go on with the project. But in biocontainment, this process requires the right materials and detail education up front in order to ensure that the seal is tight as a drum.”

Other challenges that advocate procedural testing are leakage points not visually identifiable that could be potential breaches of containment. Data cabling can leak significantly when subjected to a 2-inch pressure decay test. Visually, a cable appears to be installed correctly, but not until it is subjected to testing would it be discovered that leakage was present.

“No one really had any data to back up any single solution. We went through a series of mock-ups working through different possibilities with the tradesmen until we arrived at a solution that did pass the pressure decay test without compromising the data transmission rate,” says Zynda.

Many devices that are required to monitor temperature, pressure, and humidity and pass the stringent 4-inch pressure decay testing required of the fully welded ductwork system just aren’t commercially available. A pressure sensor was created using off-the-shelf fittings and gasketed access doors were installed in the fully welded, stainless ductwork. Supply humidity sensors were located upstream of the bubble-tight damper to ensure against potential leaks.

“Off-the-shelf fittings were welded onto the duct and tested, and it turned out to be a simple, elegant solution,” says Elinski.

The team also performed an evaluation of the ductwork by helium testing. The interior surfaces of all ducts, seams, joints, and gaskets are pressurized and then tested with an industrial-type “sniffer” device to discover helium leakage and ensure a high level of ductwork integrity.

In addition to ductwork, primary containment barriers, HEPA filter housings, electronic bubble-tight dampers, and lab waste piping were required to pass pressure decay testing. Rooms that weren’t 2-inch pressure decay tested were subjected to barrier integrity testing via a soap bubble test and smoke testing. Additional testing included pressure and hydrostatic testing of double-walled lab waste piping and biological efficacy testing of the liquid effluent decontamination system.

A series of training sessions were established to familiarize trade contractors with the intricacies of biocontainment details. This series of training and testing contributed to education because contractors not only understood the initial concepts, but because of their understanding of the biocontainment intent behind the details they were also able to bring good ideas to the project.

“You take advantage of their construction knowledge and apply it to biocontainment, and it is very successful,” says Elinski.

By putting the team together in a collaborative effort, they were able to identify the best processes, construct several mock-up scenarios, and arrive at the best solutions.

LB