Saw this today on my inspection of any old 1950’s house. There is a basement kitchen sink behind this wall.
Studor vent
The way it is installed is acceptable?..I have never seen this setup on the exterior of the house…On the interior countless times but never on the exterior
If under sink is acceptable and it is, what would be wrong with outside?
I would check with Studor if you really need to know. UV degradation might be a concern
Kind of a weird set up but if you have air behind water like in this case then it should work. Around here that would be frozen solid. -18F today. Brrrrrrrr!!
Wimp! We hit -29 wind chill.:mrgreen:
um that is -18F. that would be -28C without wind chill. Last I heard it was -37 with the wind.
I am thinking susceptibility to physical damage or possibly the vent being clogged up with insects, wasps, etc…
I can see it freezing but they are permitted in attic spaces.
Technically an Air Admittance Valve. Studor is just one of many Brands.
-18f is pretty much the same as -28 lol
It should not be done this way … Risk of freezing just to start, material degradation, appears to have been done by a non-professional !!! My opinion anyway !!
What is the black portion made of and is it an acceptable DWV material?
Looks like a mission coupling.
And answer is yes.
It’s a Fernco coupling - fully weather acceptable.
Well, obviously it is not in Maine and it would not fly by any standard that I know of. 
Studor vent, if it is, not allowed in Maine.
Point?
Now that is cold! Current temperature is -25C no windchill so you win we did not hit that figure.
Mission was the first and that is what real plumbers call them.
Similar to kleenex