Air shower for Class B gowning entry

Is it acceptable to have air shower after sterile area class B gowning before entry ?
How to classify this air shower at rest while its ventilation unit works only for seconds and stops until the next entry?

Air shower should be placed before entering the classified area only.

what do you mean by classified area do you mean class D?

Absolutely right, I am agree with sir

What if it is after class B gowning room how it will be monitored and classified specially that the air flow is not continuous an works only during washing cycles ?