Development of ventilation rates and design information for laboratory animal facilities: Part 2 - laboratory tests

Eight ventilation parameters (room air exchange rate, diffuser neck diameter, diffuser type, number of returns, return location, cage type, room size, and cage rack arrangement) for laboratory animal facilities were studied in a full-scale room ventilation simulator. Air exchange rates, velocities, and temperatures within the room and the cages were studied. Room airflow pattern and cage airflow patterns were determined using smoke tests. Cage conditions varied widely among cages within the same room. Cage type was the most important factor influencing cage conditions. Room air exchange rate, air velocity approaching the cage, number of returns, return location, and diffuser type did not significantly influence cage conditions in the ranges studied. Room air velocities approaching the cage were not high enough to have a major influence on shoebox cage ventilation rate. 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.