Experimental and laboratory situations often require animal storage in interior facilities prior to the animal treatment due to requirements for adaptation, acclimatization, or quarantine. Animal species normally dictates whether they may be stored in colonies or in individual cages, but in either case the population density (number of animals per unit space volume) may be high. Even though the Laboratory Animal Welfare Act of 1966 and its 1970 amendment (1,2) specify the sizes of cages and number of animals that may be housed per cage, the premium on floor space in these storage facilities often forces the high population density storage.

Environmental conditions of the animal storage facility must be controlled therefore, and the variables that must be considered include: (1) temperature and humidity, (2) ventilation rates, (3) room pressurization, (4) air distribution, (5) gaseous contamination, (6) population density, (7) animal species, (8) husbandry and sanitation, and (9) odor.

Optimum environmental control systems must be designed to control these variables including their variousinteractions.

Some guidelines have been suggested for temperature, humidity and ventilation rates in animal storage facilities. (7,8,9) Based upon these conditions, it was decided to begin this research program by first monitoring animal heat and moisture dissipation rates and to compare them with Standard Metabolic Rates (SMR) reported by Kleiber. (10) The method of direct calorimetry has been employed in this project to measure the heat and moisture dissipation rates. This minimizes the restraints imposed on the animals from devices such as respirometers and produces conditions similar to those actually experienced by the animals in storage facilities.