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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
Series Set Three 
In the third series set, the parallel cage orientation with CO 2 tracer gas was repeated with the 
heater on and the heater off for only the 20 and 40 fpm (0.10 and 0.20 m/s) air velocities to 
determine if the heater had a significant effect. 
Series Sets Four and Five 
Series sets four and five compared two tracer gas methods: the decay method and the constant 
injection method. In both methods, CO 2 was injected at 100 mL/min (3.53e-3 ft 3 /min) in the 
same locations as in series set one. A simulated mice obstruction (SMO) occupied approximately 
the same volume, produced the same sensible heat, and had approximately the same surface 
temperature as five mice in a tight group. The tests were run at three approach air velocities: 20, 
30 and 40 fpm (0.10, 0.15 and 0.20 m/s respectively), and three cage orientations to airflow 
(parallel, perpendicular and vertical). 
It should be noted that the primary reason for the series set four experimental tests was to 
replicate and expand the work performed by Keller, White, Snyder, and Lang (1989). In 
particular, in that paper, the authors measured decay data for a cage that was orientated in the 
parallel direction, and was subject to an approach velocity of 16 fpm (0.08m/s). The cage used in 
the Keller, White, Snyder, and Lang (1989) paper was very similar to that used in this present 
study. The emphasis of this experimental data set is to demonstrate that the experimental 
procedure being utilized in the current study was technically correct, and that the cage 
considered was representative of a typical mouse cage. 
Series Sets Six and Seven 
Series sets six and seven were conducted with the filter lid on but with a seal around the lip 
edges so all airflow through the cage passed through the filter, or with the filter lid sealed and the 
lip edge open. These results were compared to the results from series set three. The tests were 
similar to series set three except for the sealed edge and top, only the constant injection method 
was used, and only the 20 and 40 fpm (0.10 and 0.20 m/s) air velocities were used with only 
parallel and perpendicular airflow orientations. Also, during part of this series set, the SMO was 
introduced into the cage in place of the resistor, as a heat source. Data were collected using a 
randomized complete block design with the lid condition being blocked. The SMO was always 
allowed to produce heat. The heater state and air velocity levels were randomized within each lid 
condition block. 
Series Set Eight 
Series set eight was conducted with pairs of cages together, as shown in figures 4.15 and 4.16. In 
these tests, two cages were considered side by side for both the parallel and perpendicular cage 
orientations with the spacing between the cages set to that that the cages would experience in an 
animal facility room. In particular, the spacing between the cages in both cases was set to 2.8 le- 
