Offset of 3" stack drain, is this allowed?

[Higgs]

Hello guys and gals, hope all is well and thanks for taking the time to read provide your EXPERT advice to this matter.

I am renovating my home and in order to make more space in kitchen I am offseting a 3" stack drain line as shown in pictures. I am using 45 fittings and making it as short as possible. above the offset there are two sets of bathrooms draining into this line as follow:

1st bath room/1st. floor, has a shower tub with a 1 1/2" drain line with its own vent connected to a 2" dry vent. A toillet with a 3"x3"x2" DWV 90° elbow with 2" low heal inlet where a double sink vanity with a 2" drain line is connected. The double vanity sink has its own 2" dry vent.

2nd. batroom/2nd. floor , same configuration as above but it's a shower base instead of a shower tub.

The 2" inch pipe that also shows an offset is a vent line, is a dry vent from the inverted sanity tee that runs all the way up and connects at the top of the 3" stack under discussion.

Below the offset there is a 4" stack portion made of cast iron piping. In case you wonder, there is a 3" horizontal drain running with the kitchen sink and a half bath (one toillet/one sink) running on that line. See pictures for refence, this a split level home in case the location of these pipes makes no sense to you.

Any advice on what may wrong is highly appreciated or better yet, how to make this one better is equally appreciated.

 

[wwhitney]

Only skimmed the text and photos, but will comment that the plumbing codes consider 45 degree from plumb to be the limit of "vertical". So while you are offsetting the stack, it's considered a vertical offset.

NJ uses the NSPC, a unusual plumbing code, which you can read here (may require a free account):

New Jersey UCC Plumbing Subcode 2021 based on the NSPC 2021

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Chapter 11 is "Sanitary Drainage" and includes "11.6.1 Vertical Offsets. An offset in a drain stack that is 45 degrees or more from horizontal shall be sized as a straight vertical stack in accordance with Table 11.5.1B."

So while I'm not familiar with the full NSPC, I believe that means that the vertical offset has no consequences for any of the NSPC requirements relevant to you. [There is one other search hit for "vertical offset" in Chapter 11, but it only applies to the condition of 5 stories above the vertical offset.]

Cheers, Wayne

 

[Sponsor]

 

[Higgs]

Only skimmed the text and photos, but will comment that the plumbing codes consider 45 degree from plumb to be the limit of "vertical". So while you are offsetting the stack, it's considered a vertical offset.

NJ uses the NSPC, a unusual plumbing code, which you can read here (may require a free account):

New Jersey UCC Plumbing Subcode 2021 based on the NSPC 2021

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Chapter 11 is "Sanitary Drainage" and includes "11.6.1 Vertical Offsets. An offset in a drain stack that is 45 degrees or more from horizontal shall be sized as a straight vertical stack in accordance with Table 11.5.1B."

So while I'm not familiar with the full NSPC, I believe that means that the vertical offset has no consequences for any of the NSPC requirements relevant to you. [There is one other search hit for "vertical offset" in Chapter 11, but it only applies to the condition of 5 stores above the vertical offset.]

Cheers, Wayne

Thanks Wayne really appreciate your time and response.