Vent Filter Temparature for Purified water storage Tank

Dear All,

Please clerify that what should be vent filter temp. of purified water storage tank in distribution system of an OSD facility.

Also suggest any guideline which specifies the limit of vent filter temp.

I am talking about during operation not during sanitization.

Please revert

Thanks in Advance

Parveen Garg

I am not aware of any guidelines that specify the temperature. But out of practice, the vent filter heater is typically set to 95C to keep the filter from clogging with moisture and preventing the venting of the vessel.


Dear all,

is there any specific time interval to heat/dry the vent filter or it is to be heat continuously. actually we are heating the vent filter through steam at the time of sanitization.

Thanks & Regards

This is an area in which a little care is needed due the risk of tank collapse…a common occurrence if the tank is not full-vacuum rated. There are inline vent heaters, water jackets built into the filter housing, and more recently self-regulating ceramic elements. Temp? at >80C constant dry heat some degradation of the plastic hardware is fairly common (a white powder at the bottom of the housing)…usually the filters are still integral (but should be integrity tested). Time?..normally for ptfe membrane filters approx. 40-60min will restore around 80% of the flow (the filter setup should always be oversized for tanks). The inline heaters can speed this up a fair bit. If you need to Water Intrusion Test post-drying, the filters need to be bone-dry, so the drying might take a couple of hours.
Regards Moz

If you are running a WFI tank then I would recommend the PALL - HTPFR cartridges or capsules. I have attached the validation guide, these filters are constructed from a more heat resistant cage and material.