Volume II - 8 
Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
• The animal room was intended to be kept at 22.2 °C (72.0 °F), with temperature control 
performed on the exhaust air temperature. 
• No leakage occurred into or out of the animal room other than that specified though the 
cracks around the door. 
• Air density variations due to temperature were negligible. Density variation was therefore 
ignored in all terms apart from in the momentum term for the vertical velocity component. 
This is known as the Boussinesq approximation. 
• The levels of CO 2 and NH3 were so diluted in the whole room simulations, even at their 
source, that the variation of the mixture density due to differing molecular weights was 
negligible. 
1.2 Whole Room Configurations 
To investigate a range of parameters, the basic model described in section 1.1 was modified. 
Wherever possible, only one parameter was varied at a time to fully assess the effect. 
The list of room runs as they were considered is given in table 1.01. Parameters considered in 
this report are as follows: 
• Supply Diffuser Type: Three different diffuser types were considered in this project: radial 
diffusers, low induction diffusers, and slot diffusers. While all these diffuser types are ceiling 
mounted diffusers, the flow patterns resulting from them are fundamentally different. See 
volume I, section 4.2.2 and figures 1.05 to 1.07). 
