does it necessary to make integrity test for vent filters during production ?
If you’re talking about vent filters located at purified or WFI tanks you should to make integrity tests at least every 6 months.
Yes,it’s mandatory for every product.
In water system the vent filter integrity frequency is quarterly.
It is mandatory to check post integrity of the air vent filters in order to ensure the sterile inert atmosphere in holding tank, filling pumps, buffer tank etc which comes into direct contact with bulk solution.