Volume I 
Page I 
EXECUTIVE SUMMARY 
Optimum air quality in laboratory animal facilities is essential for the general health and 
well-being of researchers, animal caregivers, and the animals, as well as for the integrity of the 
studies. Since both genetic heritage and the environment influence biological responses, 
researchers must always be aware of the influence of the environment on the animals’ biological 
responses. With more information about environmental effects, laboratory animal facility design 
and management can be improved. Researchers will obtain the most reliable and repeatable 
results from their studies and experiments when laboratory animals have the best possible 
environmental conditions. 
Many thousands of square feet of animal research facilities are designed and constructed each 
year. Unfortunately, inadequate information is available regarding ventilation rates and patterns 
that are required to maintain acceptable micro (cage) and macro (room) environments. There is 
an immediate need for a definitive scientific basis for selecting the ventilation rates and for 
designing effective ventilation systems for laboratory animal facilities. Engineers need this 
information to design environments with good air quality and low energy. 
Current ventilation guidelines are based largely on anthropomorphic views and not on 
scientifically defined animal needs. Most research has focused solely on room conditions. 
Limited research has addressed ventilation rates, room air distribution, relative humidity and 
temperature, and other factors and interactions that contribute to acceptable and uniform 
environments for laboratory animals. 
Laboratory animal ventilation should balance air quality, animal comfort, and energy efficiency 
to provide cage environments that optimize animal welfare and research results. Conditions that 
optimize animal welfare minimize unintended stress factors that can affect research results. 
Researchers and animal caregivers have the right to expect a healthy and pleasant working 
environment. 
The literature review described in section 1.3 identifies the following important factors in 
controlling the macro- and microenvironments: 
• Ventilation in filter top cages does not necessarily increase with increasing room 
ventilation air change rates 
• The filter top can significantly affect cage ventilation performance 
• Improved cage washing procedures and animal room cleanliness may reduce the 
concentrations of ammonia that produce bacteria 
• Bedding type can significantly affect ammonia generation 
• Ammonia concentration over 25 ppm promotes the infection in rats’ respiratory tracts 
• A recent study suggests that groups of five mice display a behavioral and autonomic 
thermoneutral zone that is surprisingly similar to individual mice. Individual and group- 
