The guidelines for animal facilities are designed to meet projected holding and programmatic requirements while providing for expansion and flexibility in space utilization. The standards adhered to by the NIAID call for cost-effective design, construction, operation, and maintenance of biocontainment facilities.

"We want to provide efficient management through innovation and flexible design; utilize effective design and construction techniques to minimize the future costs of energy, maintenance, labor, and expansion projects; and we want to provide an ergonomic and user-friendly work environment," says John DeLeonardis, animal program administrator and chief animal scientist at NIAID's Bethesda campus. "Consistent operations from design to daily operating procedures provide value-added benefits."

Using tried-and-true design principles benefits all end users, including the scientists, maintenance staff, and administrative staff, by ensuring maximum safety from biohazards, creating a versatile workforce accustomed to standard operating procedures, preventing disruption of research, facilitating easier repairs and renovations, and holding down expenses through the utilization of long-lasting, low-maintenance construction products.

"Of course, the maximum benefit is reproducibility where we can minimize research variability and get an accurate interpretation of lab results," notes DeLeonardis.

Achieving Key Operational Objectives

The NIAID has established five key objectives that must be met through the design, construction, and operation of any animal BSL (ABSL) facility. Specifically, the goals focus on agent containment and security, provision of conditioned air, food and water supply for the animals, adequate veterinary and husbandry care, as well as research application and user functions.

"All of the operational objectives are very basic," says DeLeonardis. "We design our facilities to meet those needs by getting optimal output from them no matter what level of biocontainment is necessary."

The standards are intended as a useful tool that can be used to design any animal facility with ABSL-3 and ABSL-4 labs. Striving towards the objectives begins with the selection of a qualified architectural and engineering team to complete the design and pre-construction work. It is important to choose project participants who have experience in the design and construction of animal facilities.

Then, input is gathered from individuals who will be working in the facility to develop a rough blueprint of what the project will look like. A construction team makes the blueprints come to life by building a facility that meets NIAID’s needs.

Selecting Equipment and Maximizing Resources

Work in the ABSL-3 animal facility is conducted with indigenous or exotic agents that may cause serious or potentially lethal disease as a result of exposure by inhalation. Personnel working in the ABSL-3 labs have specific training necessary to handle pathogenic and potentially lethal agents. All procedures involving the manipulation of infectious material are conducted within biological safety cabinets or other physical containment devices.

The lab personnel working in an ABSL-4 environment have specific training in handling extremely hazardous infectious agents. Procedures are conducted within Class II or Class III biological safety cabinets used with one-piece, positive-pressure personnel suits. The area has special engineering and design features to prevent microorganisms from being disseminated into the environment.

"The function of a biological safety cabinet is the same no matter what animal species is involved or what the use is," explains DeLeonardis. "We're concerned about agent containment, personnel protection, and product protection. Therefore, the function is static; however the use may be quite dynamic. Proper planning and equipment selection is critical from a usability standpoint."

Safety cabinets and animal change stations should be mobile enough to meet alternative room layouts and provide optimal ergonomics. Versatility of the equipment is also an important factor, considering the need to transition to different species and to provide appropriate access for employees who care for the animals and maintain the cages.

Choosing equipment that is both functional and practical is vital to maximizing available space. Equipment must be compatible in size with the design of the building to ensure it will fit into the area where it will be used without compromising the work of other personnel or making the work environment uncomfortable.

Resources can be maximized by using existing space for dual purposes. For instance, isolated corridors can be used as autoclaves, staging areas, or pass-through and fumigation rooms.

Facilities employing a pathologist should consider the work space needed for personnel working in this field. Necessary equipment might include a downdraft table, grossing station, biosafety cabinet, ducted hood to vent chemicals, and bench top space.

Isolation cubicles are sometimes used in ABSL-3 labs to house animals, but they are not suitable for agent containment. The cubicles provide the NIAID the ability to maximize limited resources by housing multiple species in the same room, separated by individual cubicles, for short periods of time as scientists transition through research protocols.

Quality Finishes

The interior surfaces of animal facilities should feature finishes that are easy to disinfect, capable of withstanding routine wet cleaning, durable enough to handle heavy use or abuse, and have minimal seams or penetrations, providing reduced locations for harborage of insect and vermin bacteria.

The walls, floors, and ceilings in ABSL-3 labs must be water-resistant for ease in cleaning while maintaining containment. The walls, floors, and ceilings in ABSL-4 areas must form an internal seal. Design specifications typically call for 100 percent silicone caulking to be used as a sealant because it does not deteriorate and is resistant to mildew and temperature changes. New sealants on the market provide many of the same performance standards however they are also paintable. Paintable sealants should be evaluated for use in areas where a sealed then painted surface creates a more uniform finish. A certified quality manager (CQM) working with the NIAID is responsible for detecting any design flaws.

Walls made of a high-density concrete masonry unit provide a quality block density, but the cost can be prohibitive. As an alternative, a less expensive type of block can be used and then topped with a technique called parging, or applying a mortar-based aggregate to fill in any pin holes.

If access panels are used, they should be completely sealed with a gasket, and have a stainless steel finish with an off-set hinge to avoid gasket crimp, and three side fasteners to avoid warping. The gasket should be properly maintained to prevent dry rot and the access panel should not be caulked closed.

"Access panels should be avoided when possible in biocontainment areas. If the money is available, put in an interstitial space," advises DeLeonardis. "Alternatively, the controls can also be placed in proximity to non-contained space, or a controls corridor can be utilized on the periphery in order to provide easy access for maintenance staff."

Recessed cast electrical boxes mortared in place are also a good idea. Utility penetrations, sealed with mortar and paint, require minimal caulking and less maintenance.

Security and Safety

Doors used in animal facilities should be handle-free with recessed push/pulls for easy entry. View panels with recessed hinges and pulls are the most practical way to avoid impact with heavy equipment. Embedded rare earth magnets located in the door's lens cover and corresponding swing locations seem to work well. Door closure devices must be heavy-duty mechanisms capable of overcoming air flow and pressure differentials. A hold-open/stay mechanism is essential to keep the doors open when equipment is being transported, but the doors must close properly to maintain the appropriate air balance requirements.

Providing an effective alarm system to notify personnel when something is amiss in the lab is essential. The benefits of an audible versus visible system must be compared to see which is most appropriate for each particular area. NIAID discovered that a fire alarm was not always effective in getting everyone's attention when they were dressed in ABSL-3 and ABSL-4 protective equipment. A horn, dimmer lights, and flashing strobe lights can be tied into an integrated life safety communication system.

Providing a technologically advanced system to help scientists and other staff members communicate better with each other is imperative to eliminating mistakes caused by miscommunication. Web-based applications and personal data assistants are effective for storing and relaying information pertaining to animal husbandry and clinical care, census data, technical matters, and suite details.

Designing a proper HVAC system to meet the needs of the animal facility is a must. Factors that should be considered in the planning stage include pathological response to agents, routes of transmission, cleaning and decontamination, and adaptability for future use. Direct connection of the animal racks to the house HEPA is recommended to support high-density ventilated caging. Direct connection aides in heat removal, reduction of cooling requirements, ammonia removal, and the elimination of pheromones—odors produced by animals which may affect the behavior of other animals.

Auxiliary and emergency equipment, as well as personal protective gear, should be stored in a safe, but convenient, area near the lab entrances. Special attention should be considered when designing these areas. Ample space, appropriate storage for the gear (wall hooks, shelving, etc.) and power for battery-operated equipment need to be addressed in the design.

Biohazardous waste procedures are used to properly dispose of animal waste, bedding, and biological tissues. Mouse drinking water often contains acid and, therefore, must be neutralized before disposal. Proper consideration for disposal of acidified water should be addressed during design.

Parting Words

"Getting to know as much as possible about the end users' operations will help create an efficient facility that is manageable on a day-to-day basis," says DeLeonardis. "Understanding their general operating procedures upfront will minimize problems during construction and eventual operation."

Information about the end user should include typical equipment uses and applications, work flow application, and safety policies.

"Capturing all of the necessary information is the only way to design a building that will meet the needs of its users for many years," says DeLeonardis.

By Tracy Carbasho