Volume I - Section II - Animal Room Variations 
Page II - 3 
In all cases, the room was considered under dark period conditions, i.e., the lights were off and 
produced no additional heat load. Dark period conditions were chosen because early 
experimental work indicated that heat, C0 2 , and NH 3 generations were higher in the dark period 
compared with the lights-on period. Figure 2.02 shows the variation in NH 3 generation over a 10- 
day period. For C0 2 the generation in the light period was 0.68 g/hr/lOOg BW compared to 0.91 
g/hr/lOOg BW for the dark period. 
S 4 8 . 0 0 E - 0 3 
w . 
e® 6.00E-03 
30 % 
RH 
ligh 
75 % 
RH 
lig 
0 ) 7 , 
RH 
ligh 
80 % 
lig 
75 % 
RH 
’..Hi 
Figure 2.02 Effect of Photoperiod on Gaseous Exchange between the Mouse Cage and the 
Room Environment 
Rack Model 
The overall dimensions of the rack were 1.52m (60”) x 0.61m (24”) x 1.83m (72”) high, as 
shown in figure 2.03. There were six shelves in the rack. The spacing of the shelves was 0.32m 
(12.75”) top surface to top surface. The lowest shelf was at a height of 0.21m (8.25”) above the 
floor. The shelves were modeled on thin rectangular blocks. Details such as the connecting ties 
between the shelves and the rollers on which the racks move, were not modeled, as their effect on 
the overall flow field and gas concentration distributions was considered insignificant. 
