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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
Equation to calculate recovery ratio: 
Recovery ratio = 
EtOH 
(4.11) 
where: 
P CO 2 generation rate and O 2 consumption rate from sample air, L/min 
4. 1.2.6 Mass Generation Rate Calculation 
Mo. Co ^ 
V,v, C 
◄- 
P 
Mi, Ci 
Calorimeter 
where: 
mi, mo 
Ci,C, Co 
V 
v 
P 
Fresh air flow rate, kg/s 
Ammonia concentration, mg/kg 
Volume of the calorimeter, m 3 (0.225 m 3 ) 
Specific volume of air, m 3 /kg 
Ammonia production rate, mg/s 
— — = miCi + P-moCo (4.12) 
v dt 
Since mi = mo = m and C=Co, by solving the above equation we get the following result: 
p — t 
C = Ci + — (1-e v ) 
m 
(4.13) 
When the time goes to infinity, the calorimeter reaches the stable state, where the concentration 
is Ci + P/m. If we let T=V/mv, then when t=3x, the concentration will reach 95 percent of the 
stable state value. We ran our test mostly at 5 L/min flow rate. The volume of the calorimeter is 
225 L. So t is 45 minutes and after 135 minutes, the concentration will reach 95 percent of its 
stable value. We measured the ammonia concentration at the stable state. 
