Thread: Sink drain drain line configuration

Originally Posted by ROBERT YOUNG

I am not a code inspector. I want my clients to understand the manufactured name of the fittings.

Then go to the manufacturers or wholesalers, not retailers who call things whatever they want to call them:
- http://www.charlottepipe.com/Documen...ures/BR-PK.pdf (page 37 "Combination Wye and 1/8 Bend")
- http://www.lascofittings.com/assets/1824/dwv_11314.pdf (page 5 "COMBINATION WYE + 1/8 BEND")

Originally Posted by Ray Thornburg

This means that the minimum trap arm length is 3" for a 1.5" pipe and there would be 1.75" of it visible between the fittings. See attached photo. In the photo the trap arm I cut was exactly 3" long.

Attachment 33234

Measuring properly is key.

Seem the revised measurements I added - you don't "need" a 3" long piece of pipe, and the space you point out to as 1.75" can actually be as little as 13/16" for those fittings.

Here is an example of measurements of the fittings and the lengths of the various aspects of fittings: http://www.lascofittings.com/assets/1824/tech40.pdf
- Go to file page 2/20, the tee fitting, the line for 1-1/2" size, you can do the math two ways:
- - L - 2G or H-G either way gives the slip connector end being 1-5/16" long ... which is just about what I said in my post, and twice that is almost the 3" required (1-5/16 + 1-5/16 = 2 5/8, and if the pipe is not ALL the way in, as in not exactly square cut on the end, then some additional length is gained, but I'm not going there, let's presume that the pipe is cut square as it should be and that there is NO glue stopping the pipe from being inserted ALL the way ... 3/8" is all that would be shown with that fitting) , which is also what I said in my post.

It all depends on the fittings.

The reason I am using those pressure fitting dimensions is that I have not been able to find a source for DWV fittings which shows the overall length of the fittings to calculate the slip joint length from - here are two examples of DWV dimensions without overall length dimensions:
- http://www.lascofittings.com/assets/1824/dwvtech.pdf
- http://www.charlottepipe.com/Documen...C-DWV(609).pdf

My next step will be to stop by the Lowe's store (which is about 5-7 minutes away) and measure some DWV fittings, hope to be able to do that within the next few days (just got back from Asheville, NC).

What to heck, went to Lowe's earlier this evening ...

I did the following under "field conditions" as is often done in the field.

The first photo shows measuring off 2" on a piece of 1-1/2" PVC. I cut it with a hacksaw (which means it may come out at 2" angles in to less, or at 2" angled out to more (extremely difficult to get a square cut with a hacksaw).

2 x pipe dia 01.jpg

I glued the 2" piece of pipe into the sanitary tee and then glued on the trap bend, forcing each in as much as I could.

2 x pipe dia 02.jpg

I then cut the glued together piece in half most of the way through, to show the interior of it for measurement purposes.

2 x pipe dia 03.jpg

Then I measured the trap arm length from the weir of the trap to the vent.

2 x pipe dia 04.jpg

The trap arm length measured right at 3-3/16".

Then I measured the distance between the two fittings.

2 x pipe dia 05.jpg

The distance between the two fittings was 11/16".

My recollection of the depth of the slip joint (and I said, as I recall) was based on pressure fittings, DWV fittings do not have as deep of a slip joint because they do not hold back pressure.

The length of the pipe necessary will depend on the depth of the slip joint on the fitting, in my case of my cut-a-way example, I "assumed" (I used "assume" intentionally instead of presume) the depth of the slip joints to be 1", so I cut the pipe to 2", that 2" long pipe, with my hacksaw variations from 2" produced a trap arm length which exceeded the required 2 times pipe diameter length.

And I thought I was passionate.
I am not worthy.