The Mitchell Building is part of The University of Texas M. D. Anderson Cancer Center, located in Houston on the campus of The Texas Medical Center. In 1941, the Texas legislature created M. D. Anderson as a component of the University of Texas system. It was one of the nation's original three comprehensive cancer centers designated by the National Cancer Act of 1971 and today is one of 52 Comprehensive Cancer Centers within the U.S.

During the last decade, M. D. Anderson has experienced explosive growth in terms of both investigators and the number of animal use protocols supported. Since 1995, the number of investigators has increased by 157 percent to a total of 291, while the number of approved protocols has risen to 697, a 263 percent increase. The average daily population of animals at the Houston campus is 60,000, a 62 percent increase over the same 10-year period.

"Our current rodent housing facilities are at maximum capacity and are located on the other side of the building complex from the rest of our department," says Stacy LeBlanc, animal facility operations manager for the Department of Veterinary Medicine and Surgery for M. D. Anderson. "The Mitchell Building's vivarium will give us expanded rodent housing and procedure space. In addition, the Mitchell Building is directly adjacent to the Clinical Research Building, where all of our other departmental functions are located thus allowing us to regain departmental unity."

Overall Building Layout

The new 16-floor facility is a full interstitial building, with even numbered floors serving as interstitial space for the odd numbered floors below. The endcaps of each interstitial floor are outside the laboratory footprint, so the space could be captured for additional office and meeting areas. The vivarium spaces located in the basement and first floor consist of animal housing, procedure, and support space. The second floor endcap contains animal colony administrative offices and a large break room with windows. The vivarium interstitial spaces are fully walkable, allowing for easy access to utilities and services, such as HVAC, electrical, telecommunications, and animal drinking water systems. Most maintenance activities can be performed without the need to enter the animal housing space.

The first floor is composed of conventional, behavioral, and biohazard housing areas, washroom complex, and the receiving dock. The basement includes barrier and conventional specific pathogen free housing areas, autoclaving complex, and support spaces such as necropsy, radiology, and clinic space. Personnel will use dedicated locker rooms and don protective clothing before entering any of the vivarium animal housing areas. The basement will also house a unique gnotobiotic rodent colony, isolated from the main colony.

"The rodents in our gnotobiotic colony are free of urease positive bacteria in the gut meaning they have a gut flora that produces very little to no ammonia in the cage." says LeBlanc.

Housing equipment for this colony will be processed in the central washroom complex, but will be sterilized in a dedicated bulk autoclave which discharges directly into the gnotobiotic colony.

The vivarium's first floor 3,000-sf washroom complex contains three bulk autoclaves for decontamination of biohazard housing equipment, two tunnelwashers and bedding dispensers, one cage and rack washer, rack water manifold flush station, recoil hose flush station, water bottle filler, a large walk-in feed storage cooler for in-use feed, and one one bulk autoclave for sterile equipment. The basement's 3,000-sf autoclaving complex has four bulk autoclaves, one of which is dedicated to the gnotobiotic colony. All housing equipment used in the basement will be sterilized. A dedicated loading dock specifically for animals and animal supplies includes a quarantine room, bedding storage, and two large feed storage coolers for newly received feed.

Flexible Suites

Animal housing within the vivarium will be located in a series of 15 suites, based on a boilerplate design of five holding rooms and three procedure rooms. This layout will enable investigators to actually work with animals within the vivarium, eliminating the need to transport animals to various labs. One suite will be dedicated to research involving biohazard materials and two suites will be used exclusively for the gnotobiotic colony. Two are half-suites, one dedicated to a transgenic mouse production core facility and the other to a behavioral study group.

"Flexibility of usage is one of the major design goals for our research suites," says LeBlanc. "Since the type of equipment researchers need varies depending on the type of research being conducted, we need the flexibility to easily convert procedure rooms into animal housing or vice versa, whenever necessary."

Each procedure room contains only a limited amount of fixed casework with the rest being modular equipment racks that can be easily removed to make room for animal housing equipment. All housing and procedure rooms are identical in terms of environment, environmental monitoring, and finishes.

In each procedure room, there are downdraft workstations where investigators can conduct research requiring an exhaust system, such as volatile anesthetics, gas scavenging, and/or dander control. Procedure rooms are also equipped with numerous electrical outlets and data ports, so investigators can outfit their procedure space with microscopes, centrifuges, computers, or any other benchtop equipment.

Ventilated Racks

When completed, the new building will include space for approximately 400 racks, either static cage racks or ventilated cage racks. To accommodate the ventilated racks, exhaust connections in the animal housing rooms are equipped with open collar thimble connections to eliminate the need for load simulators or iris dampers.

Each exhaust drop will be balanced to 75 cfm. Exhaust from a vent rack blower trolley in excess of 75 cfm will recirculate back into the room. Conversely, if a blower trolley output is lower than 75 cfm, makeup air will be pulled from the room. According to LeBlanc, open collar thimble connections increase overall room flexibility because it does not matter whether a rack is attached to achieve initial air balance.

Automated Systems

Each suite has a graphical user interface (GUI) box, a touch screen panel with access to the Windows-based building automation system (BAS) software. Real time room conditions including temperature, relative humidity, differential pressure, and light level will be visible on the screen. With proper password access, the complete BAS can be accessed for maintenance, troubleshooting, or monitoring purposes from any GUI box.

In the BSRB, water bottle use is reduced as much as possible. The vivarium is equipped with an automated animal drinking water system with online rack flushing. All ventilated cage racks are equipped with water manifolds.

"When we first started using automated water we had problems with flooded cages," says LeBlanc. "To correct this, the vendor held training for our staff responsible for the actual animal care, instead of just training the supervisors and letting the supervisors train the animal care staff."

LeBlanc adds that in addition to animal care staff training, the facilities maintenance staff works closely with the watering system vendor to learn about ongoing equipment maintenance, including troubleshooting and minor repair of the system's components. Once the staff was properly trained, the problems resolved.

Other automated systems being installed within the vivarium include a Pyxis scrubs dispensing system and a vacuum bedding system. The Pyxis system will provide tight control over scrubs inventories, which are notoriously hard to manage. The vacuum bedding system, made possible by a Department of Health and Human Services construction and renovation grant, will allow for the ergonomic and safe handling of animal bedding. At maximum capacity, approximately three to four tons of bedding will be used per week. Bedding will be provided in half-ton bulk bags, which will be emptied via a vacuum wand into the storage silos. The dedicated vacuum system waste container is sized to handle the maximum waste volume when emptied twice per week.

The Imaging Facility

"A critical component of our new building will be the 2,000-sf imaging facility, located in the basement," says LeBlanc. "As a non-invasive way of monitoring an animal throughout a project, imaging is a very powerful tool and has been identified as a significant scientific opportunity by the National Cancer Institute."

This state-of-the-art core imaging facility supports virtually every imaging modality that exists for research purposes, including Micro CT, Micro PET, Micro-MR, optical, and ultrasound imaging. Since it is a core facility, it must be accessible to all rodents regardless of where they are housed. The imaging facility includes two separate animal preparation/procedure rooms, one dedicated to basement-housed animals and the other to first floor-housed animals.

Traffic Flow & Contamination Control

To enhance contamination control, the vivarium is laid out in a modified dual corridor system. Separate corridors are designated clean or soiled so there will be virtually no cross traffic of clean and soiled equipment other than in the actual suite corridor. Investigators will access the facility through the clean corridors so that they will not pass by soiled equipment.

Clean equipment will be distributed to animal housing suites via the clean corridors, and soiled equipment will be returned to the washroom via dedicated soiled corridors. Cages destined for the basement will be transferred to the basement autoclaving complex via the clean elevator. Soiled cages from the basement are returned to the first floor washroom via a dedicated soiled elevator.

Support spaces in the basement, including imaging, clinic, cryopreservation, irradiator, and radiology can be accessed from either the center barrier hallway or from the outer non-barrier corridor. This dual access eliminated the need to duplicate support services on both floors. Contamination control will be accomplished procedurally with barrier animals used first then non-barrier animals, with the room decontaminated at the end of the day.

Locker Rooms

Entry into each of the three animal housing area entrances (first floor, basement, basement gnotobiotic) is through a dedicated set of locker rooms. Each housing area also has an equipment airlock, which provides for additional contamination control because tools and equipment can be sprayed down before entering the area. Each of the locker rooms will have 40 half-lockers, some of which will be permanently assigned to the animal care staff with unassigned lockers available on a first come, first served basis.

"We discovered after the fact that, in spite of how nice the layout looked on paper, we still had line of sight problems in the basement barrier locker rooms," says LeBlanc. "To correct this, we strategically placed curtains at the exit doorways. These curtains shield the dressing area from people passing by in the hallway. This was a valuable design lesson that we are not going to repeat in our next facility."

Lessons Learned

"Although this project has taken us longer than expected, the delays have actually taught us a great deal about what we really want in this facility and future projects," says LeBlanc. "We have also been able to modify our original plans to take advantage of new technology in ventilated caging that was introduced during the construction phase. Since one of our goals for this facility was flexibility, we were able to incorporate this new technology relatively easily."

Value engineering (VE) should be accomplished in such a way that it actually provides long-term value. Too often, VE becomes just a euphemism for cost cutting. A cost savings up front can have very expensive long-term consequences if ramifications of the proposed change are not considered during VE decision-making. As an example, LeBlanc points to phone lines and overhead paging that were deleted for cost reasons. The consequence of this decision was that it deleted virtually all means of communication with and between animal care staff.  Ultimately the phones and overhead paging speakers were added back, but at a much higher cost.

In an effort to maximize animal housing and procedure space, support spaces are sometimes minimized or overlooked. Adequate support spaces must be planned from the onset of design. For example, a first-floor storage room within the Mitchell Building had to be converted into a janitor closet, since the only existing one on the first floor served biohazard only.

Take a thorough look at code compliance issues such as egress paths throughout the facility. According to LeBlanc, the facility team working on the Mitchell Building had to correct "dead end" corridors after the walls were already up. Relocation of an existing corridor door and reversal of door swing on another was done in order to meet egress path code requirements. Another example was benches that had to be added to all locker rooms to comply with Americans with Disabilities Act requirements.

Communication with the end user during the facility design and planning phase is critical. LeBlanc adds that the end user, particularly facility maintenance personnel, should be allowed a strong voice in planning decision-making. This is especially important when considering VE changes.

By Amy Cammell and Stacy LeBlanc

We welcome your Questions and Comments

Copyright 2008 Tradeline Inc.
All Rights Reserved
ISSN: 1096-4894