Plumbing vent question

[Thomas D. Phillips]

Should this type have a cap of some sort? There is a clamp at the top that makes it seem like something is missing.

[Jeffrey R. Pope]

If it's a plumbing vent - no cap needed. If it's an exhaust type vent (which is what it looks like) it should have a cap.

[Thomas D. Phillips]

Yeah it kinda looks like an exhaust, but after the attic crawl I could see it was plumbing. This one is at the back of the home above the bath, one at the front just like it for the kitchen. Weird for plumbing vent IMO.

[Paul W. Abernathy]

Interesting....if the vent is designed properly it will allow air through it. This one seems to have a flapper on the top which would make the effects of venting pointless.

[Thomas D. Phillips]

No flapper, seems like a double wall construction, inside is vent and outside is flashing. Just not sure why there would be a clamp, unless that holds the assembly together.

[Chuck Evans]

I would call it atypical. Looks like it could leak at the rusty clamp from the picture.

Looks like an expensive and possibly ineffective way to flash a plumbing vent to me.

P.S. I really don't like that itty bitty flange at the sides of the jack, wouldn't take much wind to drive water past that.