Baylor College of Medicine's goal of attracting and retaining world-class scientists has resulted in the completion of the Transgenic Mouse Facility. Within the Facility are the centralized research operations and a redundantly supplied, well-controlled environment for its 215,000 transgenic mice.
Baylor's Transgenic Mouse Facility occupies more than 82,000 sf of space on one below-grade floor and contains 57 transgenic animal rooms in 12 suites for its 43,000 mice cages. A greenhouse plaza sits atop the structure and the foundation is sized to support a future eight-story, 224,000-gsf research tower for future expansion above the Facility.
The Facility has both barrier and non-barrier areas utilizing the holding suite concept, which reduces research risk by isolating groups of rooms and keeping the main equipment traffic away from the holding rooms. Each room holds up to 756 mouse cages in six single-sided and three double-sided ventilated racks, providing more than two cages per square foot.
The Facility features fully robotic cage handling and wash systems and a bottle filling system with a unique movable cage and rack system. Specifically engineered for this application, the robotics have not been used in this type of system before. Despite a higher initial cost, a full-scale cost analysis determined that the automation system would pay for itself in slightly more than four years.
The robotic cage wash room has the ability to process 4,500 cages daily. Engineers use a vacuum propelled bedding-transfer system that was integrated with the ventilation system to dispose of the bedding and additional waste materials. All waste is removed pneumatically and transferred automatically to sealed dumpsters outside the building.
A centralized HVAC system allows strict control of each individual room to accommodate NIH standards of no more than a two-degree temperature variation and to provide 20 air changes per hour in each animal room. Each room also has the capability to switch between positive to negative air flow.
The design fully integrates the building-automation functions to include control over lighting levels and an important reporting/recording function. The electrical system provides redundancy for the life-support systems in the vivarium. A diesel generator provides emergency backup for heating, cooling, ventilation and lighting loads. Steam and chilled water is provided to the site by the TECO central plant located within the Texas Medical Center.
Each cage rack has a duct system that is directly attached to air-in and air-out connections. Each cage, a clear enclosure about the size of a shoebox, attaches to a ventilation nozzle connected to the rack-duct system. Moving the fan motors for the caging system above the ceiling and animal rooms streamlines maintenance and eliminates the need to expose service personnel to the animals. One fan/filter per room proves to be more cost-effective than one rack, and locating the fan and ductwork above the room requires less duct usage and design time, and improves sanitation by eliminating a possible dust ledge in the room.
Each room has one portable clean air work station for cage and cleaning purposes. The four-foot, six-inch aisles allow the changing stations and material carts to be closely located to the racks. This improves the cage cleaning system and reduces the exposure of staff to allergens, improves the air flow to the mice, and allows for a longer cage-changing rotation. Half the procedure rooms have fixed biosafety cabinets with stainless steel adjustable casework and a sink.
The barrier facility is located to be expanded or contracted easily by the opening and closing of cross-corridor doors. It offers one-way clean/dirty traffic flow whereby clean and sterile cages are transported to the barrier directly from the sterile cage staging room where they are autoclaved. The animal receiving area utilizes pass-through biosafety cabinets for personnel and animal protection. The barrier lockers utilize air showers and crossover benches to reinforce the barrier concept. Automatic doors are used throughout the corridor system to facilitate cart movement. Complete robotic automation is used in the cagewash area, as well as enclosed bedding dispensing and disposal systems for economic, ergonomic, and allergy control.
One of the challenges in this space was a constricted interstitial space between the ceiling of the facility and the courtyard above--a floor-to-floor height of 17 ½', as opposed to the typical 21'. A computer model, and later a full-scale model, of the interstitial zone wove together ducts, pipes, wiring, structure, and maintenance work areas to ensure that the systems not only fit together, but would be serviceable and maintainable.