Abstract: Objective To assess the variation of air changes and pressure parameters in the same equipment of individually ventilated cage (IVC) during the daily operation.Methods Taking the onsite single-side IVC as the test object which was placed in the barrier environment,and the parameters were set like this:ventilation rate 50 times/h,40 times/h;the pressure:+ 20Pa,+ 10Pa.The sample points were set at the air inlet,which was used to test the air speed,meanwhile testing the pressure between the cage inside and outside.Result During the IVC equipment daily operation,the variation of air changes among the cages were huge,the number ranged from 30 times/h to 60 times/h,but the parameter of pressure between inside and outside has little difference among the cage,and within the set value ±5Pa range fluctuations.Conclusion The structure and ventilation system of IVC equipment had big impact on the air changes,the temperature,humidity,airflow velocity and ammonia concentration in IVC cage were closely related to the ventilation rate.In order to reduce the environmental differences on the experimental results,controlling the ventilation rate and pressure difference between internal and external of cages are necessary.

Key words: Individually ventilated cage (IVC), Air Changes, Pressure, Laboratory Animal