Some of you will remember my post last week about a stinky kitchen drain in this thread:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=88000.29
The setup looked like this:
A number of you replied, and IMO this is the best aspect of forums like this: A problem is stated, a diverse array of opinions are discussed, and a course of action emerges. In this case big Shouts Out are in order for Mike Hennesey and McDesign (If I recall correctly, thanks to everyone else too).
In this case the solution is simple: build a parallel trap for each drain, not in series. No more stink. Like this:
Works like a charm.
Thanks.
Scott.
Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.â€
Edited 4/5/2007 9:54 am by Scott
Replies
I might be wrong - someone will correct me if I am, I'm sure :-) - but I think what you have done by adding the second trap is add another fixture unit to the equation and thereby overloaded the 1 1/2" pipe that goes through the bottom of the cabinet. Or at least it looks like a 1.5" pipe. I know this doesn't make total sense, but from my limited understanding of plumbing code, I think that is the case. Not saying it is necessarily a problem, just trying to spark some controversial :-) conversation.
This has come up in the past.And IIRC others have said that it was not legal. But mine has been like that for alsmot 30 years without any problem. And I have seen many others like it.But - "but I think what you have done by adding the second trap is add another fixture unit to the equation and thereby overloaded the 1 1/2" pipe that goes through the bottom of the cabinet. Or at least it looks like a 1.5" pipe."I don't buy it at all.No units have been added. NO change in flows have been done. In both cases you have 1.5" tail pieces being combined into a common 1.5" pipe into the DWV. No more, no less.The problem, IF ANY, has to do with the venting of the two traps.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I believe 2 traps need a 2" waste pipe.
You're right, Matt, and I'm sure he's exceeded the allowance for that size box. This a common problem. People think they can cram all kinds of drains, pipe, tubing, valves into just any sized box. The drain line will have to be de-rated. They have special box entenders for this application.
Greg
What kind of BOX are you talking about..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I believe he is tongue-in-cheeking an electrical reference.
Bob
Edited 4/5/2007 9:53 am ET by rasconc
Sorry, Bill. I forgot the wink.
; > )
Greg
Yeah, you gotta worry about overheating.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I don't know squat about plumbing.
But I appreciate it when someone posts back to let us know how things turned out. I hope you'll keep us posted on whether or not this solves the problem.
My take on the situation:
I think the 2 traps as configured are code compliant, no increse in fixture units.
The dw discharge location will help scour or clean the drainline, thereby cutting down or eliminating oders.
It's tough to tell from the pictures, but the traps look to be 2" and the house drain line at the back corner looks to be 1 1/2". I always thought that drains could not be reduced in diameter. (the only exception I know of is 4" to 3" for toilets right at the sweep). If this is a optical delusion- my apoligies.
>>>It's tough to tell from the pictures, but the traps look to be 2" and the house drain line at the back corner looks to be 1 1/2".No, it's a 'delusion' as you say. It's all 1 1/2". I'm going to check my code book today about the fixture unit issue.Thanks,Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
View Image
Parolee # 53804
rez..you da man!! my eyes thank yee!!
Geoff
ya, but now you can see the spiderwebs on the vent pipe.View Image
Parolee # 53804
Ok - ya got me! That's a pretty obnoxious .gif!
It looks great, Scott, but why does it make a difference? It's not obvious to me why two traps in parallel limit sewer gas to the sink any better than one.
Is it possible that you simply replaced a cracked line when you did your refit?
Mike
I think that there are two differences. One is DW connection on the tail piece. The other is fixing the negative slope IF THERE WAS..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
ditto datSamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
One is DW connection on the tail piece. The other is fixing the negative slope
That's my bet, too. The old connection allowed some quantity of stagnant water, from any source, to sit in the untrapped side. And "grey water" has a very short smell "lifespan" at the best of times. So, the entire line from d/w to drain was open, too. Now, that's all isolated from open air by the new trap.Occupational hazard of my occupation not being around (sorry Bubba)
The problem wasn't sewer gas from beyond the trap, it was stinky junk building up in the horizontal pipe furthest from the trap. The addition of the second trap means that the only pipe before the trap is the tailpiece; no more tailpiece --> elbow --> DW drain --> horizontal before the trap.As for negative slope, nope, I had checked and rechecked that with a level. There was at least "half a bubble" of slope.It works great now. I just need to crack the code book to check up on it.Thanks all,Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
Edited 4/5/2007 2:14 pm by Scott
It works great now. I just need to crack the code book to check up on it.
snort* Now that's funny right there!
Parolee # 53804
If your plumbing inspector hassles you for some reason about the dfu's, ask him to count the number of faucets that serve that one double bowled sink. One kitchen sink = 2 fixture units in my code book. There's no separate section for a double bowled sink equalling any more (at least where I am).
Only problem I can see is what happens if someone were to use only one side of the sink out of habit and the "uphill" trap could get dry. One fixture = one trap where I am so that might become an issue.
"Let's get crack-a-lackin" --- Adam Carolla
Fill the space with cleaning products, toilet brushes and plunger, watering cans for houseplants, etc. No one will ever check.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Take another look at his pics. Actually, I'm thinking the origin of the stinky drain is that the food strainers don't work very well in the bottom of the cabinet. ;-)
I am going to tell the inspector! Yep , I will call in tomorrow. Yep I will tell! This guy is in big trouble!
Just an observation , well and a question too. If his new setup were reversed wouldn't the Dw and sink suck the water out of the upstream trap and leave it dry due to suction?
Actually won't this happen if he drains a full bowl of water out of the first sink in line ?
What's your take on having 2 traps feeding into one 1 1/2" waste pipe?
It's against the code, & very early in my career I found that out the hardway by having to repipe 85 kitchen sinks in a fire damage apt complex we repiped.
Now in reality it probably won't be a problem, & like most things codes tend to be overkill & side with being safe than sorry.
Code wise you would use a "continuous waste" system
WASTE_PIC
“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
And the stinky stuff ( bacteria ) can and do build up in vertical pipes.
>>>Now in reality it probably won't be a problem, & like most things codes tend to be overkill & side with being safe than sorry.Thanks, PB, I was hoping you'd drop by. The drain definitely works well and doesn't stink any more. I'm currently reading about hydraulic load, fixture units, and pipe sizing. I think it conforms with our code (BC, Canada) but will report back asap.Rez.... rolfing.....Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
>> It's against the code, & very early in my career I found that out the hardway by having to repipe 85 kitchen sinks in a fire damage apt complex we repiped. <<
Why is it against code?
And... I didn't quite get the purpose of the link you posted.
Edited 4/6/2007 7:15 am ET by Matt
Sorry about the link I just googled continuous waste pics here's the link to the pic http://www.labgeardirect.com/images/aero/aero-drain-s-21.jpg
Chapter 10 of the UPC the end of the very first paragraph of the chaptor 1001.1
"Not more than one trap (1) shall be permitted on a trap arm"“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
88161.34 in reply to 88161.32
Sorry about the link I just googled continuous waste pics here's the link to the pic http://www.labgeardirect.com/images/aero/aero-drain-s-21.jpg
Chapter 10 of the UPC the end of the very first paragraph of the chaptor 1001.1
"Not more than one trap (1) shall be permitted on a trap arm"
Plumbill
Don't you consider this application to have 2 trap arms, thereby making it code compliant.
As a side note, I'm not thrilled with the idea of 2 traps when 1 would suffice.
No, a trap arm goes from the trap weir all the way to the vent, then it becomes a drain not a trap arm.
He shouldn't have had a "stinky drain" to begin with since the branch inlet was upstream of the trap.
His fix of puting in a "branch tail piece" is standard for that application, but didn't need to add the second trap.
The job I first spoke of where it was a costly mistake, we installed "double wye's" with two traps & a cleanout in the middle. It made perfect sence to us & looked good, but the anal retentave inspector made us change out every last one.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
"we installed "double wye's" with two traps & a cleanout in the middle"Bill,Your description sound just like what I did. This hasn't had a final inspection yet, but I thought I did this correctly. Am I going to have a problem?Thanks,
Jerry
Edited 4/7/2007 12:38 am ET by Jerry18
Well that has two seperate traps with two seperate trap arms with a common vent.
That is quite common for back to back fixtures, although not usually exposed under a sink, but the format is legal.
Just one problem, & it's only if the inspector gets picky, or really knows the code indepth.
When installing back to back fixtures there are two types of fittings used. A "san-cross" like you have in the pic, & a figure "5" fitting AKA a "fixture cross" which has more slope than a "san-cross" but not as much as a "double combo".
San cross's when used for a back to back fitting it has to be atleast two pipe sizes larger--- so an example would be back to back lavs, lavs only require a 1.25" trap arm so a 2" san cross can be used, but a kitchen sink requires a 1.5" trap arm so 2 sizes bigger would be 2.5".
Now they don't make a 2.5" fitting so you would need to increase to 3".
But since technicaly since you don't have 2 fixtures it should be OK, but inspectors have the final say.
FYI if you use a fixture cross you don't have to increase the pipe sizes.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
"the format is legal."Well that's a relief - I guess you were describing something else when you spoke of the problem you had. "FYI if you use a fixture cross you don't have to increase the pipe sizes."Thanks for the education - I thought a san-cross was OK in this situation. If he catches it (and I doubt he will) I will have to squeeze a fixture cross in there. Increasing to 3" at this point would be out of the question. Would you happen to know why the increased slope of a fix-cross is required and how the increased pipe size with a san-cross negates that need? Not really seeing what they're after on this one.BTW, That mess couldn't go in the wall because the floor framing is recessed into the foundation wall and the walls sit on top of the foundation. I didn't have the foresight to cast the drain into the foundation, so it had to come through the floor. The vent goes back into the wall. (Tried to at least make it neat).Jerry
The double "wye" we put in was horizontal going into the stub-out comming out of the back of the cabinet. That is also illegal, the 2 trap arm problem, & you can't put a double "wye" in horizontaly. When we got tagged for it the inspector just brought up the 2 trap arm violation though.
The reason for the increased pipe size when using a san-cross is so that when draining a large flow it will have a better chance of going down the drain verses going into the other side branch.
The fixture cross has more of a downward slope directing the waste down instead of straight across to the other side inlet, it is real similar to a double combo.
But the double combo does not allow the venting action to happen since its' opening is below that of the side inlet, which could siphon the trap under the right circumstances.
So that's why they introduced the fixture cross its' vent comes off the fitting above the bottom of the side inlets, if you go to this link from Tyler¯ on page 12 in the bottom right hand corner is a fig5 fixture cross. http://www.tylerpipe.com/utility%20catalog%202007/pg12-13.pdf
“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
"But since technicaly since you don't have 2 fixtures it should be OK"...just thought of another potential problem. Would this be considered two fixtures or one?Thanks,
Jerryhttp://forums.taunton.com/n/docs/docDownload.aspx?guid=4AB6AD5C-DAA6-4B42-87B4-C00131B6C4C3&webtag=tp-breaktime
Edited 4/7/2007 7:28 am ET by Jerry18
Try again...
No , still a single kitchen sink.
When doing commercial kitchens the fixture count changes when multiple compartment with multiple faucets are used.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works. Nigel Calder, editor of New Scientist
But they do show a high expertise in manipulating the public to achieve their own desires.SamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
Careful, that's Tavern Talk.:)
Bill,Thanks for the explanation - looking at diagrams for both fittings, I can see what you mean. If the inspector doesn't catch it, do you think it is worth correcting. In case it might influence your answer - except for the tailpieces, everything is 2". Not to nitpick, just trying to learn, but this picture shows that although the sink is one piece, it is two bowls with two faucets. It still only counts as two FU's?JerryEdited 4/7/2007 10:55 pm ET by Jerry18
Edited 4/7/2007 10:56 pm ET by Jerry18
No, I wouldn't fix it unless the inspector tagged it. Worst case scenario if you dump an extremely large amount of water down one bowl & the drain can't handle the flow it will just back up into the other bowl which is the same fixture.
Yes your sink is 2 fu's, according to the UPC table 7-3 a residential kitchen sink is a residential kitchen sink, with or without a garbage disposal & or a dishwasher hooked up to it. I have put as many as 4 faucets on a residential kitchen sink--- standard hot/cold faucet, instahot, chilled glass filler, & a separate deck mount pot filler.
Now if it was a commercial kitchen sink in a commercial building, then the rules change drastically.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
Question: Is that black tube the dish washer drain?
BTW - nice to see plumbing run neatly through the floor of the cabinet. In the OP's pic, did you notice how the cabinet had to be chopped based on where the plumber had set his DWV. I HATE that.
Yes, that is the DW drain.Jerry
>> Yes, that is the DW drain. <<
Does it at some point go up to the very top of the cabinet - nearly touching the bottom of the counter top, or is there an "air gap" somplace in the line?
BTW - like I said at first, my knowledge of plumbing code is pretty weak, but I'm 90% sure our local plumbing inspectors would accept the 2 P-traps and the 2" drain pipe - that based on what I have seen them pass before - many times.
"Does it at some point go up to the very top of the cabinet..."Matt,Thanks for your input on the two traps and the polite question about my DW drain. :-) There is no air gap and the drain line does not loop up to the underside of the counter top near the sink, but it does behind the DW, so I should be OK. Correct?Jerry
Yes - you should be OK
Hey Bill,
What do you do with a garbage disposal in a dual sink? The waste would shoot into the second sink.
I plumbed mine with two traps too to stop that mess.
Depending on configuration, we mainly use a continuous waste set up of some sort either a center outlet or an end outlet.
The "T" that joins the two together will have a diversion plate inside it of some sort.
More common on pvc ones than brass.
My DMIL has two traps, but also has two stub outs under the sink.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
Hi Again PB.So I dug out my trusty code book and can't find anything that outright prohibits two traps. For those who are interested, here's an excerpt:1) Except as provided in Sentences (2), (3), (4), and (5), and in Article 7.4.5.2, every fixture shall be protected by a separate trap.2) One trap may protect
(a) all the trays or compartments of a 2- or 3-compartment sink,
(b) a 2-compartment laundry tray, or
(c) 2 similar single compartment fixtures located in the same room.blah blah blah.... sentences 3, 4, and 5 go on to talk about one trap may protect multiple floor drains, shower drains, and other details unrelated to this. There is no mention of one trap per trap arm. I don't see anything that says you can't provide a trap for each fixture.However, one of the previous posters mentioned that fixture units may be an issue. Our code does indicate that 1.5 FU's (don't you love that acronym) are the limit here. Oh well.....BTW, the smell is gone.Thanks all,Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
I'm gonna guess that's from the IRC.
Here in Wa state the IRC is not adopted for plumbing, & electrical it is for enverything else though IIRC.
The code I quoted from is the 2003 UPC with the updated amendments.
As far as fixture units you're OK, cause the sink FU's over ride the trap fu's.
The only time a trap is counted for fixture units is when it is used for an indirect waste recepticle.“When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.” Nigel Calder, editor of New Scientist
Thanks, I hope I can return the favor.All the best,Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
Very pretty work there under the sink. So clean and well-lit. So unlike mine. Even looks like the angle stops are solid brass vs. The Usual Junk.
I replaced my rotting collection of brass kitchen drains with 1.5" ABS. You might find that you can screw a 1.5" adapter onto the drains and run 1.5 all the way up.
I have Fernco 1.5-1.5 connectors at the stub-out and under the drains so I can just back off the clamps and remove the whole assembly when there is a problem. This has worked so well that all the sinks now have something similar. No more leaking compression fittings. No more cheesey thin white tubes.
The ToolBear
"Never met a man who couldn't teach me something." Anon.
Regarding feeding a double-bowl sink and a DW into a 1-1/2" drain -- that's always been approved by my inspectors. (Haven't checked the code, though.)
Only one comment on your revised setup. It looks to me like you fed your one trap into the horizontal with a horizontal Tee. That would get nixed -- should probably be a wye.
Check out the photo in post #41. Methinks that's the "kosher" way to do it.
Mike Hennessy
Pittsburgh, PA
Edited 4/9/2007 8:17 am ET by MikeHennessy
Hi Mike.>>>Check out the photo in post #41. Methinks that's the "kosher" way to do it.Yes, I'd have to agree that that setup would flow better, but I've got the problem of a rough-in that is way off center of the sink cabinet (darn plumber! and my plans even showed millwork!). You may have noticed my cabinet-ectomy work in the pics; there's no room for a wye. Nonetheless, it seems to work really well. I even dumped big pots of water down both sides at once. No issues.Thanks though, you're the first to notice that.Scott.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”