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Veiatilatiora Design Handbook on Animal Research Facilities Using Static Microisolators 
Before the detailed comparison of the room configurations, which follows this section, a few 
general remarks on the results are appropriate. 
The ventilation in the rooms was designed to produce 22.2 °C (72.0 °F) at the exhausts in the 
room (except for cases 99-101). This leads to the room and cage temperatures that do not vary 
greatly. The variation that does occur seems to be mostly due to temperature stratification in the 
rooms (i.e., the temperature rises towards the ceiling) in combination with the exhaust position. 
A low level exhaust means that the design temperature of 22.2 °C (72.0 °F) is the “lowest” in the 
room whereas a high level exhaust means the temperature should be below 22.2 °C (72.0 °F) in 
the room. 
The CO 2 concentrations are a simple indicator of the ventilation in the room and cages. High 
values indicate poor ventilation. Good ventilation of the cages can lead to higher values in the 
room space. 
The NH3 concentration data are more complex measures of the ventilation as they also depend 
on the relative humidity in the cages, which is also dependent on the temperature. Therefore, 
poor ventilation of cages at a high temperature and low humidity may produce low NH3 
concentrations. 
In making comparisons among the values shown for the cages on the charts, it is important to 
consider if the differences in the mean values (the average for all cages) is statistically 
significant. The ANOVA test (see section 6 ) can be used to determine significant differences. 
This test was run for several pairs of datasets. In each case the differences were found to be 
significant, except when the means were actually identical. Please note that comparing 101 
datasets with each other for 4 data values produces more than 40,000 tests. This seems to be a 
result of having 210 or 420 cages in the rooms. Each one appears as a sampling point for the test. 
With so many samples the test becomes very sensitive and even small variations in means are 
statistically significant. 
3. LI Supply Type and Exhaust Position 
Cases 1 to 9 allow an easy comparison of the effect of Supply type and exhaust position. Cases 1 
(the basecase) to 3 had a radial diffuser supply with ceiling, high level (on side walls) and low 
level (on side walls) exhausts, respectively. Cases 4 to 6 used a slot diffuser, and cases 7 to 9 a 
low induction diffuser with the same exhaust configurations. 
Figures 3.09 to 3.16 show three-dimensional bar charts comparing temperature, CO 2 , NH 3 , and 
relative humidity for both the cages and scientists’ breathing zone in the center of the room. 
