The NSPC permits s-traps?

**Noth Jersey** · 07-01-2010, 08:58 AM

Originally Posted by Terry

What you describe on the framing is normal framing. We manage to plumb correctly under those circumstances daily.
A plumber would have it done in less time that it takes to type this. It's that easy.

Do you want pipes coming up through the cabinet taking up space?
It seems a shame to cut up a new cabinet for a pipe that shouldn't have been there.
The finish carpenter is going to love you for making his job harder.

I am the finish carpenter.

I'm actually interested in learning the proper technique for my personal edification, so if I've missed an easy solution, I want to learn.

Plumbers typically aren't interested in doing small increments of work, and rightly so, without charging me a hefty flat fee per service call. The nature of my remodel is such that the plumbing, flooring, and the drywall must be done in small increments.

With a standard installation, I would have to punch a hole into an adjacent cabinet, saw a large hole for the 45 degree vent (I need to offset because I can't shoot straight through the sill plate without cutting a 1" deep channel down my rim joist), and punch a hole for the drain line through the bottom of the adjacent cabinet.

I could also run the trap arm through three cabinets and into a bearing wall, but I believe this wall sits directly on the main girder.

Going straight out the back of the sink base cabinet is not possible because the window sill is built up with horizontally stacked 2x4s to accommodate a window that was significantly shorter than the original rough opening. Even if we had cripples below the window instead of solid wood, I'm not sure I could get the vent up to 42" before going horizontal. I would also have to put a 2" hole through 2x4 king and jack studs, which would require some sort of Simpson tie reinforcement.

If I'm missing a really obvious solution, please let me know. I would prefer to keep all the pvc in one cabinet and drill a single hole in the cabinets.

**Ian Gills** · 07-01-2010, 09:00 AM

a 2" trap arm/drain is sufficient to avoid siphoning on a 1-1/2" p-trap. Can anyone corroborate with a real-life anecdote?

A lot is to do with the distance between the trap and the vent. I have a 1.5 inch p-trap on a 1.5 inch pipe for my laundry tub. But it is just over 42 inches away from the vent. The trap gulps after the tub has drained. I am going to have to shorten the distance.

If you have just shy of five feet of pipe between your trap and your vent then you will need 2 inch pipe. Any more than 5 feet and you will run into the same problems as me.

Although Table 12.8.1 shows something different. Where am I going wrong here?

**Noth Jersey** · 07-01-2010, 09:30 AM

Well, the table specifies lengths based on the trap arm size (1-1/2" in my case). A 1-1/2" trap corresponds to a developed length of five feet. If the drain is horizontal until you hit the sanitary tee for the vent, you should still have 18 inches to remain code compliant. In fact, according to the table, 42 inches should be fine for 1-1/4". Are you dipping below the crown weir before you tie into the vent? You can have up to 3 DFUs on a horizontal drain, and I believe a standard laundry tub counts for two. I'm not a pro, so I'm not the best one to help you troubleshoot, but I would make sure your vent is clear of obstructions and that the p-trap is not reversed.

**MACPLUMB 777** · 07-01-2010, 11:23 AM

I would follow terry's recommendation come out of the top of the tee 90

over below your

stacked wood, then outside the window space 90 up though the roof is

how real plumbers would get it done,

or install aav on top of the tee as high as possible

**Noth Jersey** · 07-01-2010, 11:54 AM

Mac,

The trouble is those stacked 2x4s start at about 38 inches above the finished floor. I'm pretty sure the inspector will not allow me an exception from the requirement to keep that horizontal vent six inches above the flood rim of my fixture. In NJ, we have to have an engineer design the AAV. He might allow me to augment the combination waste-vent type installation, but I'm a little reluctant to introduce a mechanical vent that will one day fail and introduce sewer gas into the house. Do you know of an AAV with some sort of fail-safe, i.e., it automatically closes off when it fails?

**Terry** · 07-01-2010, 05:11 PM

Which ever way you go, could you post some pictures when done?
Terry

**SewerRatz** · 07-01-2010, 05:42 PM

Hi guys. Here in Illinois it is against code to run the disposal into a end waste and use a single trap. Each fixture has to have its own trap. The way we do it is a 2" line in the wall come out with a 1 1/2 double Wye. The center of the double Wye would be the clean out, then each side of the double Wye would have a trap. So the picture here is not that far off base to what meets the Illinois plumbing code.

**Noth Jersey** · 07-01-2010, 07:14 PM

Originally Posted by Terry

Which ever way you go, could you post some pictures when done?
Terry

If I'm ever done, I'll gladly post some pictures.

Originally Posted by SewerRatz

Hi guys. Here in Illinois it is against code to run the disposal into a end waste and use a single trap. Each fixture has to have its own trap. The way we do it is a 2" line in the wall come out with a 1 1/2 double Wye. The center of the double Wye would be the clean out, then each side of the double Wye would have a trap. So the picture here is not that far off base to what meets the Illinois plumbing code.

Terry and Doherty tell me the type of installation in the picture will result in siphoning. Have you ever experienced this phenomenon with your double wye configuration?

**SewerRatz** · 07-02-2010, 08:53 AM

Originally Posted by Noth Jersey

If I'm ever done, I'll gladly post some pictures.

Terry and Doherty tell me the type of installation in the picture will result in siphoning. Have you ever experienced this phenomenon with your double wye configuration?

Nope never had an issue. As I said its allowed here in Illinois. Its best to check with your local plumbing inspector to see what meets the code by you.

**Noth Jersey** · 07-02-2010, 10:53 AM

Why not disconnect the p-trap at the union for a cleanout? What's the benefit of the double wye?

**Terry** · 07-02-2010, 11:00 AM

There always needs to be a cleanout on a kitchen sink.
The double wye makes sense too. One trap doesn't run by the other like in the first drawing, it's more like a double fixture fitting in that the arms come in equally and not by each other. The cleanout in the center would be the same in other codes as the clean out either on the arm or on the vertical below.
Kitchens need cleaning out more then most other fixtures because of the grease, and from the disposers.

**Noth Jersey** · 07-02-2010, 01:34 PM

Here's a related thread: http://www.terrylove.com/forums/show...ty-%28again%29

Here's the relevant NSPC excerpt on the other thread:

I believe exception number 3 indicates that the end outlet continuous waste fitting is acceptable.

**Terry** · 07-02-2010, 01:42 PM

It would seem to be true, however we always have to look at the local inspector and please him or her.

Years ago, I plumbed seven meat markets for a large chain. Since the stores were located in different cities and counties, I had to meet with each local inspector to find out how I was going to pass inspection. Everything was supposed to be UPC code, however I wound up plumbing each one differently.