Any 2 in. x 2 in. x 1-1/4 in. x 1-1/4 in. Double Fixture Tee?

[Jian]

No stud holes option: lift up floor boards, penetrate the bottom plate in two separate stud bays for the two separate drains, join them horizontal in the floor joists. Similarly for the vents/top plates/ceiling joists. Your horizontal drain looks pretty high in the joist bay, and holes in the joists have to be at least 2" clear from the top of joist, so this may not be possible.

Maximum copper (requires soldering) option: PVC 2x2x1-1/2x1-1/2 double fixture tee, short 1-1/2" pipe segment, 1-1/2" PVC x 1-1/4" Cu DWV Fernco, bore through studs with 1-1/2" hole, DWV 1-1/4" Cu elbow, 1-1/4" copper trap adapter.

https://www.homedepot.com/p/Everbil...e-Cup-x-Cup-Elbow-Fitting-C907HD114/100201834

Minimum copper (no soldering): same as above through the studs, then another 1-1/2" PVC x 1-1/4" Cu DWV Fernco, with a 1-1/2" x 1-1/4" PVC bushing glued on 1-1/4" PVC pipe, a 1-1/4" PVC DWV elbow, 1-1/4" PVC trap adapter

https://www.menards.com/main/plumbi...-degree-elbow-dwv/k055250/p-1444449184942.htm

Cheers, Wayne

For the minimum cooper (no soldering) option, there will be waste line size changes from 1-1/4'' PVC to 1-1/2'' PVC, and to 1-1/4'' Cu, finally to 1-1/2'' PVC on the double fixture tee. Will there be any problem of size changes of getting bigger and then smaller?

 

[Reach4]

For the minimum cooper (no soldering) option, there will be waste line size changes from 1-1/4'' PVC to 1-1/2'' PVC, and to 1-1/4'' Cu, finally to 1-1/2'' PVC on the double fixture tee. Will there be any problem of size changes of getting bigger and then smaller?

Things start over going up and down at the double fixture fitting or sanitary tee. You can get bigger as your vent goes up from there. You can get bigger as your drain comes down from there. You can get bigger as you go from the lavatory to the santee/double fixture fitting.

 

[Sponsor]

 

[wwhitney]

It's just 1-1/4" PVC to 1-1/4" Cu to 1-1/2" PVC, no downstream-ward reduction in size.

It would be nice if Fernco (or Mission, I haven't checked) made a 1-1/4" Cu to 1-1/4" Plastic (or 1-1/2" Cu, they seem to be the same OD). But if you put a 1-1/2" x 1-1/4" bushing on the outside of a piece of 1-1/4" PVC pipe, the 1-1/2" Plastic side of the Fernco should seal to the bushing.

I guess there's a concern that the bushing is not a full 1" deep, while the Fernco has a 1" depth. So perhaps this is ill-advised, and some further research on adapting from 1-1/4" PVC to 1-1/4" Cu would be required.

Cheers, Wayne

 

[wwhitney]

Mission makes a K-1125, so that would work without a bushing:

https://www.missionrubber.com/product/band-seal-specialty-couplings-k-series-part-0801613/

Cheers, Wayne

 

[Jian]

Mission makes a K-1125, so that would work without a bushing:

https://www.missionrubber.com/product/band-seal-specialty-couplings-k-series-part-0801613/

Cheers, Wayne

Good finding for 1-1/4'' copper coupling! For the 1-1/4'' plan, I also could not find any 1-1/4'' long sweep elbow for either PVC or copper. Two 45 degree elbows instead might be required.

Here is another option that is possible for the 1-1/2'' waste line. It does require a stud hole size of at least 1.625'' for 1-1/2'' Cu line and threaded fitting. It is going to be PVC 2''x1-1/2''x1-1/2''x1-1/2'' double fixture tee, short 1-1/2'' PVC & 1-1/2'' Hub*FIPT PVC, 1-1/2'' male Cu adapter soldered to 1-1/2'' Cu, 1-1/2'' 90 degree long radius elbow Cu, and finally 1-1/2'' Cu. For the short 1-1/2'' PVC&1-1/2'' Hub*FIPT PVC, the configuration could also be replaced with 1-1/2'' spigot*FIPT PVC adapter, and the rest will the same with 1-1/2'' copper line soldered with male adapter.

 

[wwhitney]

For the 1-1/4'' plan, I also could not find any 1-1/4'' long sweep elbow for either PVC or copper. Two 45 degree elbows instead might be required.

So, for a lav trap arm, I'm not sure if "long turn" is required. Under the IPC, it is explicitly not required, medium turn is fine. You'd have to check the Massachusetts code to see what it says on change of direction fittings. Also, the fact that the copper DWV makers have medium turn elbows in 1-1/4" and up, but long turn elbows only start at 1-1/2", is suggestive of the long turn not being required.

1-1/2'' Hub*FIPT PVC, 1-1/2'' male Cu adapter soldered to 1-1/2'' Cu

For metal to plastic threaded joints, I definitely prefer plastic male to metal female. But I think I'd prefer a Fernco joint to a threaded DWV joint, to me it seems more reliable/easier to execute properly.

Cheers, Wayne

 

[Reach4]

I also could not find any 1-1/4'' long sweep elbow for either PVC or copper. Two 45 degree elbows instead might be required.

See 3rd and 4th link in #16.

This is street type, but two cups are available too.

Another option is one 45, and have the trap arm at an angle to the wall.

 

[wwhitney]

Those are long turn 1-1/4" pressure copper fittings, not DWV copper fittings. So I doubt the sweep would match what you would get from two DWV 45s.

Edit: OK, I was mistaken. Nibco 906 DWV 45 degrees in 1-1/4" shows a radius of curvature of 1.2". Nibco 607-LT pressure long turn 90 degrees in 1-1/4" shows a radius of curvature of 1.88". On the other hand, Nibco 907 DWV 90 degrees in 1-1/4" shows a radius of curvature of 1.19", so it already matches (2) 45s (but is more compact because there's no straight section in the middle).

Cheers, Wayne

 

[wwhitney]

P.S. In case anyone likes minutiae, here's the radii of curvature of the curved portion only of various 1-1/2" fittings. The copper data is from Nibco, and the plastic data is from Charlotte:

Copper DWV 45 1.35"
Copper DWV 90 1.44"
Copper DWV LT90 2.31"
Copper Pressure LT90 2.25"
Plastic DWV 45 2.72"
Plastic DWV 90 1.75"
Plastic DWV LT90 2.75"

Rather surprised by the first line.

Cheers, Wayne

 

[Jian]

So, for a lav trap arm, I'm not sure if "long turn" is required. Under the IPC, it is explicitly not required, medium turn is fine. You'd have to check the Massachusetts code to see what it says on change of direction fittings. Also, the fact that the copper DWV makers have medium turn elbows in 1-1/4" and up, but long turn elbows only start at 1-1/2", is suggestive of the long turn not being required.


For metal to plastic threaded joints, I definitely prefer plastic male to metal female. But I think I'd prefer a Fernco joint to a threaded DWV joint, to me it seems more reliable/easier to execute properly.

Cheers, Wayne

Thanks for the suggestions! Then I will use the Fernco Flexible coupling. I did more calculations that the void space between two studs is 13-3/4'', which is enough to accommodate two Fernco coupling (2*2.13''), one double fixture tee (7.13''), and some short PVC connections.

I think I could also replace the 2''x1-1/2''x1-1/2''x1-1/2'' double fixture tee with the 2''x1-1/2''x2''x2'' double fixture tee, which probably will provide less flow frictions when transitioning from 1-1/2'' copper to 2'' PVC. Fernco actually has flex coupling for this purpose.

 

[Jian]

See 3rd and 4th link in #16.

This is street type, but two cups are available too.

Another option is one 45, and have the trap arm at an angle to the wall.

You are right the 1-1/4'' copper 90 degree long radius is available. However, I failed to find any 1-1/4'' PVC long sweep elbow.

So, for a lav trap arm, I'm not sure if "long turn" is required. Under the IPC, it is explicitly not required, medium turn is fine. You'd have to check the Massachusetts code to see what it says on change of direction fittings. Also, the fact that the copper DWV makers have medium turn elbows in 1-1/4" and up, but long turn elbows only start at 1-1/2", is suggestive of the long turn not being required.


For metal to plastic threaded joints, I definitely prefer plastic male to metal female. But I think I'd prefer a Fernco joint to a threaded DWV joint, to me it seems more reliable/easier to execute properly.

Cheers, Wayne

I guess as Wayne said, the fact that 1-1/4'' PVC elbow is not available probably suggests the 90 degree long sweep is not required or not a need.

Anyway, if anyone has such needs, you can use two 45 degree or one 45 degree with trap arm at an angle.

 

[wwhitney]

I think I could also replace the 2''x1-1/2''x1-1/2''x1-1/2'' double fixture tee with the 2''x1-1/2''x2''x2'' double fixture tee, which probably will provide less flow frictions when transitioning from 1-1/2'' copper to 2'' PVC.

I don't see the advantage of enlarging before the fixture tee. Also, I don't see that fitting in PVC in Charlotte's catalog (just in ABS); if you did find it in PVC, then judging by the ABS dimensions, it would be about 1-1/4" wider than the 2x1-1/2x1-1/2x1-1/2 double fixture tee, which starts to make the stud bay a little tight.

Cheers, Wayne

 

[Jian]

I don't see the advantage of enlarging before the fixture tee. Also, I don't see that fitting in PVC in Charlotte's catalog (just in ABS); if you did find it in PVC, then judging by the ABS dimensions, it would be about 1-1/4" wider than the 2x1-1/2x1-1/2x1-1/2 double fixture tee, which starts to make the stud bay a little tight.

Cheers, Wayne

Sure. NIBCO does make PVC 2" x 1-1/2" x 2" x 2" Hub Double Fixture Tee DWV (https://www.menards.com/main/plumbi...e-fixture-tee-dwv/k277500/p-1444449207844.htm), which appears less common than 2" x 1-1/2" x 1-1/2" x 1-1/2" Hub Double Fixture Tee .

 

[Jeff H Young]

not as clean but a 45 on a trap arm coming out the wall is common . but not everyone likes them. it also helps at times to keep trap arm lengthes withen limits of code