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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
appear to produce higher temperatures) it is better achieved by increasing the supply 
discharge temperature for high level and ceiling exhausts, resulting in less cooling in the 
room and, therefore, lower running costs. 
The experimental measurement of NH3 generation shows dependency on relative humidity. As 
relative humidity is dependent on temperature (if the level of moisture in the air is constant), 
raising the temperature in the room and cages will reduce the levels of NH3. Further, as indicated 
in the study by Gordon, Becker and Ali (1997), increasing the cage temperatures above the 
normal 22.0 to 23.0 °C (72.0 to 74.0 °F) is likely to provide a more comfortable environment for 
the mice. A recommendation of this study is that the supply discharge temperatures should be 
increased by 3.0 to 4.0 °C (5.4 to 7.2 °F) to about 23.0 °C (73.4 °F). This will provide room 
temperatures around 25 °C (77 °F) and cages with a temperature of about 26.0 °C (78.8 °F), 
though a few individual cages may rise as high as 28.0 °C (82.4 °F). 
