General Animal Housing Concepts

Types and Sizes of Animal Rooms — Basically, animal rooms can be divided into two types: rooms for housing animals using dry bedding cage systems, generally for housing small animals from rodents to rabbits, and rooms for housing animals using hose-down caging systems, generally for housing nonhuman primates, canines, and small agriculture animals in cages or floor pens. One design approach is to design all animal rooms to accommodate either type of housing system and another is to design rooms for either one system or the other. The hose-down caging system requires floors sloping to floor drains, preferably in troughs, and the presence of a hose, preferably on a hose reel. The dry bedding housing system does not necessarily require floor drains or sloped floors. The obvious advantage of designing for both types of housing systems is maximum flexibility. The disadvantage is that a room designed for both types of housing systems is not optimal for either. If it is known with a reasonable degree of certainty that only rodents will be housed in the facility, e.g., a rodent barrier facility, then a reasonable choice is to design it with no floor drains. The size and shape of the animal room can vary depending on many factors, including the species to be housed, the types of housing systems to be used, and the arrangement of the cages and racks in the room. There is no one best or ideal size, but it is important to decide on the cage type to be used as well as the placement in the room prior to deciding on sizes and shapes of the animal rooms. For example, double-sided rodent racks are typically arranged library style with multiple racks parked parallel, with the end of each rack against a common wall or two rows on opposite walls with an aisle between them. Single-sided cage racks are typically parked with the back of the rack. A combination of both types combines the advantages of both. A room with both types may have single-sided racks lined against both side walls with double racks placed end to end in the center of the room, forming two aisles between facing cage racks.

Animal Cubicles — This is an animal room concept that provides maximum flexibility for animal isolation within minimal space by dividing animal rooms into multiple small spaces, typically each large enough to hold one rack and occasionally two cage racks (Figures 8.6 and 8.7). Cubicles help solve the problem of what to do when a facility has plenty of animal housing space but too few spaces to provide the necessary separation of species, source, microbiological status, project, and experimental hazards. They were first described in 196116 and have been used extensively since then, especially for specialized housing areas, where isolation of small groups of animals and containment of hazardous or potentially hazardous agents are priorities, e.g., quarantine, biocontainment, and chemical and radioisotope containment areas. Animal cubicles typically have three solid sides, with the fourth side comprised of full panel glass doors, either vertical stacking doors or a pair of conventional hinged doors. The most common cubicle size is approximately 1.2 m deep by 1.8 m wide (4 ft x 6 ft), although, larger cubicles, e.g., 2.1 m x 2.1 m (7 ft x 7 ft), that can hold two racks and in which a person could perform simple tasks with the doors closed, are useful. The size of the room depends on the size and number of cubicles. It is recommended that the aisle between facing cubicles be maintained at a minimal width of 1.5 m (5 ft). Typically, animal cubicles are used to house smaller animals in cages on mobile cage racks using dry bedding aging systems, but the concept can also be applied to housing large animals requiring hose-down caging systems.17,18

Extensive experience over many years suggests that cubicles effectively prevent airborne infectious agents from spreading between cubicles in the same room. The reason is probably related to the brief window of opportunity for cross-contamination when a cubicle door is open and substantial dilution of the contaminant with large volumes of air ventilating the aisle and cubicles. The usefulness of animal cubicles has decreased with the advent of microisolation cages for rodents; however, cubicles continue to be useful for conventional housing of rodents and other species. Animal cubicles can be built in place or commercially prefabricated. Prefabricated cubicles typically come complete with lighting and internal ventilation, with and without HEPA filtration and the ability to switch between positive and negative relative air pressures. The many options regarding architectural and engineering features for animal cubicles and animal cubicle rooms along with pros and cons have been described in detail.17-18-19-20

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