Volume I - Section I - Introduction 
Page 1-7 
Room air velocities approaching the cage were not high enough to have a major influence 
on shoebox cage ventilation rates. Air diffusion performance index (ADPI) did not show 
a difference between the diffuser type, the number of returns, or return location, but ADPI 
did show a difference with the room ventilation rate and diffuser neck size. 
The air velocity, air temperature, and ventilation rate were measured in the room and 
within cages at selected locations in the room. The following conclusions were drawn: 
• Cage conditions varied widely with cage location in a room. 
• Cage type was the most important factor that influenced cage conditions. Wire cages 
had ventilation rates three times higher than shoebox cages even though the sensible 
heat production in the wire cage was only one-fourth that of the shoebox cage. 
• In general, room air exchange rates, velocity approaching the cage, number of returns, 
location of return, and diffuser type did not significantly influence cage conditions for 
a range of factors studied in this project. Room air velocities approaching the cage 
were not high enough to have a major influence on shoebox cage ventilation rate. 
• The thermal comfort conditions in the human-occupied region of laboratory animal 
rooms were affected by room ventilation rate. In general, ADPI had lower values at 
lower ACH. 
• ADPI did not show a difference between the diffuser types, the number of returns, or 
the return location, however, the diffuser neck size (neck velocity) did affect the 
ADPI values. 
For the range of conditions tested in this study, the number of air returns and the location 
of air returns did not have a measurable effect on cage or room conditions. The perforated 
ceiling and laminar flow diffuser performed equally well, but the neck size needs to be 
carefully matched to the overall design. Room ACH values from 5 to 15 had the same 
effect on cage conditions, so the higher room air exchange rates did not provide better 
conditions for the animals. 
This study did not address the concern of odors and contaminants in the room or the 
cages. This needs further study. However, higher ventilation rates in the cages were found 
to reduce contaminant levels in the cages. Another area that needs more study is cross- 
contamination between cages due to air movement from cage to cage. More study is 
needed to explain the wide variation of cage conditions at different locations in the same 
room. The magnitude of air velocity approaching the cage did not have a large effect on 
cage ventilation rate at the low room velocities encountered in this study. However, the 
direction of airflow approaching the cage could have a major effect and could explain 
some of the differences. More precise measurements are needed on effects of air direction 
and magnitude on cage ventilation rates. 
