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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
Figure 3.44 Comparison of Mean Cage NH 3 Concentrations (ppm) 
Figure 3.45 Comparison of Mean Breathing Zone NH 3 Concentrations (ppm) 
The in-cage values for these runs are not very different from the single density rack. The in-room 
breathing zone values are much higher. They are about double the CO2 and NH3 concentrations 
of the single density (compare with cases 19 to 24). 
Cases 62 to 68 were also double density runs with variation in air change rate. These cases were 
discussed in section 3.1.2. These cases were the worst, run with 5 ACH producing very high NH3 
concentrations in the scientist’s breathing zone. 
