Atmospheric "Membranes"

I am looking to better understand the options for atmospheric membranes for humidity sensors. I have a sensor that is inside a mechanical housing that needs access to ambient weather. I want to add something to the mechanical housing to prevent excess water (rain) from getting in the housing. I see that this is done fairly regularly but am not experienced in what these membranes are. Is it a fabric of some sort?



It’s common for such vents to be made from a thin, micro-porous hydrophobic material such as PTFE that allows gas transport while resisting passage of liquid water. We’ve got a modest selection of purpose-built products here made for venting sealed enclosures, but if you’re after something a bit more compact I believe the folks at McMaster have options in self-adhesive and bulk-material forms.

Thank you very much for your response. This helps out a bunch!

Hi zhogarth.zh,

This is not the same thing as covering the opening to a cavity which holds the sensor, but Sensirion makes some humidity sensors which come with a PTFE membrane covering the hole on the package itself to protect the actual MEMS sensor inside the package. Here’s a link to some of them.

And here: