Bow vent?

[wmn]

Can anyone explain the PVC in this photo? As you can see, the closet flange is not centered on either leg. Plus the closet flange is angled to intercept the cast iron stack with, I suspect, a wye under the concrete floor. Someone suggested a bow vent or possibily a set up for a future bath. Seems unlikely since there is a bath already (bath added in '79 and house built in 1974) and the PVC is post construction of the house (all stacks through the floor are cast iron).

 

[Jeff H Young]

st lois mo city has upc code to my little knowledge UPC allows no such type w/c vent there fore id say from a legal stanpoint it has no purpose whether it helps a w/c flush better or keeps another fixture from losing its trap seal in a semi prcatical manner maybe It might or might not some yahoo might think they accomplished something or maybe 50 years ago you had some oddball code but i doubt it was ever legal to serve any purpose in regards to the W/C

 

[Sponsor]

 

[Reach4]

My first thought was softener loop, but that would be smaller pipe, and it would not be by the closet flange.

I don't have a better guess.

 

[Jeff H Young]

further comment Ive never heard of a bow vent but googled it and it pops up as an island vent and again there is no legal use of an island vent for a w/c in the UPC code so im stumped but i lean toward some micky mouse illegal plumbing