Vent pipe

[David K. Lee]

Not sure if this pipe is acceptable. Vent pipe is a small flex pipe going into a larger pipe. There is no seal on the pipe where it is connected.

[wsiegel]

That pipe is not acceptable. Cannot be flex pipe.

[Jeffrey R. Pope]

It looks to me like that is a listed, flexible B-vent. I'm not sure it's installed properly (the pic is a bit small) where it enters the other vent.

Do you have a better picture?

[Joe Funderburk, CMI]

I agree with Jeff. Always look for a label on vent pipes. They do make flexible B-vents.

[Bruce A. King]

Looks like an old AO Smith water heater, hope you looked for rust around the bottom seam.... Or, as I do, recommend replacement just due to the age.