Horizontal wet vent discharge into vertical water closet segment

[OREE]

First post for me, so I'll try to be as clear as I can. I have a difference of opinion with my local plumbing inspector. I'm adding a second story full bath with two dry vented lavs, and a wet vented shower sharing a 2" line that discharges through a sanitary tee into the 3" water closet line shown in the picture. The combined flow makes a vertical to horizontal transition and then goes over to the main stack, which is within 6'. The inspector says I can only combine the flow from my 2" wet vent and 3" water closet in a horizontal orientation. All fixtures are on the same floor of my house.

I'm in Oregon, under the UPC. Section 706.2 seems pretty clear to me that horizontal to vertical transitions can be made with a sanitary tee, but perhaps I'm missing something. Can anyone confirm who is right here? At the end of the day, the AHJ gets to make the call, but if I'm right, I'll at least have a follow-up conversation with the inspector to see if I can convince him this is ok. He's a nice guy, and I think I can at least have the discussion with him. Currently everything is dry fitted, not solvent welded, so changes aren't too painful if I absolutely have to make them. I just don't want to change if I don't have to because what I have seems a lot cleaner and neater than what he described wanting me to do. Thanks in advance for the help.

 

[Terry]

How is the shower vented?
If the shower is vented with a lav run in 2" it would be fine. The lav/shower would then vent the toilet. If the inspector wants a wye off the toilet line, that would be easy. You could put the wye downstream of the long 90.
Terry

Bert is an inspector in Oregon.
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

Some vertical wet venting below.

 

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[OREE]

Thanks Terry. The dry vented lavs discharge into a 2" horizontal line that picks up the shower discharge horizontally through a combo fitting. Upstream of that combo is therefore the lav discharge, and the wet vent portion of the shower line. Downstream of the combo fitting is the shower/lav discharge, which enters into the sanitary tee in the picture. The inspector mentioned wanting a wye downstream of the 3" long 90, which I agree wouldn't be that difficult; it just seemed unnecessary.

Thanks for the link to Bert Polk's plumbing tips. There is a picture on the bottom right of page 14 that is very similar to what I'm doing, so I'll show that to the inspector to see if he agrees with me. If not, I guess I'll be adding the downstream wye. Thanks again.