[joescardina]

I was looking at "various methods for venting toilets" in excerpts from the UPC
( http://www.masterplumber.com/Laws/UP...ventexceptions).The last configuration shown is labeled as not allowed. It has both the vertical vent pipe and the vertical toilet discharge pipe connnecting to a horozontal drain line with the vent connecting upstream from the toilet connection. The accompanying note states that the "toilet must not discharge below vent." If the purpose of venting is to supply air to the line when the toilet is flushed, it seems like this configuration would work well. Why is it unacceptable?

Have really enjoyed this forum and have learned a lot by reading the replies to the various posts.

[speedball1]

I was looking at "various methods for venting toilets" in excerpts from the UPC
( http://www.masterplumber.com/Laws/UP...ventexceptions).The last configuration shown is labeled as not allowed. It has both the vertical vent pipe and the vertical toliet discharge pipe connnecting to a horozontal drain line with the vent connecting upstream from the toilet connection. The accompanying note states that the "toilet must not discharge below vent." If the purpose of venting is to supply air to the line when the toilet is flushed, it seems like this configuration would work well. Why is it unacceptable?

Have really enjoyed this forum and have learned a lot by reading the replies to the various posts.

The configuration shown is unacceptable because code says it is.
This is a flat vent that is not washed by a fixture, ( chapter 14, section 1406.2 and 4 and section 1422.4(b) of The Standard Plumbing Code. Which states that no vent shall take off from the horizontal waste branch at a angle of less then 45 degrees unless washed by a fixture. The vent shown takes off flat from the main and is a dry vent.
It looks like it should work but code says otherwise.
Regards, Tom