Volume I - Section III - Evaluation of Results and Recommendations 
Page III - 35 
Cases 87 to 89 were run with a reduced number of cages on each rack (28 instead of 42) for each 
supply type with low level exhausts. Apart from the slight reduction in room breathing zone CO 2 
and NH 3 concentration, no particular changes can be seen. The radial supply seems the best in 
the room and the low induction the worst, as is the case with the normal racks (42 cages). 
3.1.7 Side Cracks of Cages Sealed instead of Open 
Where the bonnet filter top sits on the bottom of the microisolator cage the CFD model allowed 
for an imperfect fit, i.e., air could enter or leave the cage via small cracks. To investigate this 
effect, three cases were run with sealed cracks, i.e., no air could enter or leave the cages except 
through the filter. 
Cases 25 to 27 were run with sealed cages instead of leaky ones for the three supply types and 
ceiling exhausts (compare with cases 1, 4 and 7). 
Figure 3.46 shows the comparison of in-cage mean temperatures and shows very little change 
difference between the normal cage model and the fully sealed one. 
Figure 3.46 Comparison of Mean Cage Temperatures (°C) 
Figures 3.47 to 3.50 show comparisons of CO 2 and NH3 concentrations for the three supply 
diffuser types with ceiling exhausts for the normal and sealed cage. 
