water delivery lines with multiple conncections- is this OK?

efsDecember 14, 2011

We had water delivery lines for our two sinks in master bathroom redone two times (initially there was a single supply for the entire bathroom with no shut off valves for the faucets at all). Then it was one shut off for both faucets and finally we have a possibility of shut off valves for each water line.

After two changes we got what is shown below (these are "back views"):

Is it of concern that we have so many "connections" and some "dead ends" there? Is it worth paying to have it redone to reduce the number of connections? If so, how many would you say are necessary?

In the new construction the tubing from the faucets can go straight down, but need to turn under the floor (ceiling of the powder room) to land within internal wall to reach the basement and make another turn to land in old basement where the water supply is located.

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"some "dead ends" there"

Dead ends are not allowed in supply lines.
They used to be used to male field 'water hammer arresters' by running the line supplying sinks above the stop valve in the wall and capping the stub off.
The trapped air acted as an arrester until it was absorbed into the water.
Then you needed to drain the system to replace the air and you had an arrester again.

Are you n a municipal supply or a well?
Is the water pressure otherwise good (not low)?

You will need that pressure to get good flow around all the bends, most of which look pretty required for using rigid pipe.

A fixture supply load calculation will tell if the flow velocity is going to be excessive.

Without knowing more about what is going to be installed there is no way to tell about flow velocity.

    Bookmark   December 15, 2011 at 5:28PM
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The code does not permit a dead end longer than 12", but contary to popular opinion it does still allow 12" to permit making vertical stubs for hammer arrestors.

    Bookmark   December 15, 2011 at 5:35PM
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I am with municipal supply, but I do not know the exact pressure of supply line is in my house. These particular faucets are far away from water entry to the house (like 70 ft from water entry to the house).

There will be two sink faucets on these lines. Since these faucet are wall mounted and no vanity under the sinks, they told us we cannot have shut off valves in the wall (they offered us valves on the bedroom wall if we wanted them on the second floor, which we declined).

Maybe I should ask- would you like to close a wall on supply lines like these shown on the picture?

Is anything in that picture against the code?

Beyond looking as something that maybe prone to leaks (so many connections and so many bends) would such delivery line create any other problems- like noise?

We thought that with PEX we should be able to get a continuous line (maybe with two or three bends with connections when it turns wall to ceiling and ceiling to wall) from the basement all the way to these faucets.

The shower and toilet are supplied with different lines.

    Bookmark   December 15, 2011 at 6:18PM
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Take what I say with a grain of salt. I'm not a plumber, but I play one on TV.

That seems like a lot of unnecessary corners to me. I don't understand why the pipes in the left stud bay are coming towards the camera and then back again.

And is the cold pipe on the right side looping around the electrical wires? Wouldn't it have been easier to just push the wires out of the way and go straight?

    Bookmark   December 16, 2011 at 2:40PM
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I'm not a plumber either. But can you have cutoff valves in the wall if there is a 'door' in front of them?

With the double thickness of this wall I'm surprised at the double zigzag the pipes on the left are doing.

And I'll ask: is there some standard or best practice with PEX installation that restricts how much 'bend' or stress you can have on the pipe and where it meets a fitting?

    Bookmark   December 16, 2011 at 4:35PM
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the big black pipe is DWV: has anyone told you the cross is 3/4 S trap? Post it on terrylove.com

    Bookmark   December 16, 2011 at 6:23PM
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"...the big black pipe is DWV: has anyone told you the cross is 3/4 S trap? Post it on terrylove.com..."

may I ask why? and maybe what for?

    Bookmark   December 16, 2011 at 6:36PM
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OK, I posted it. we shall see...

    Bookmark   December 16, 2011 at 7:12PM
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I ama plumber, but at this point I hardly know where to start.

First off...I only see two dead ends, which I marked on the photo with a ? mark.

Now in regards to how many fittings they used on the PEX. For the lines on the right hand side of the center DWV stack they had no choice. The required bends would have been too tight for 1/2" PEX so they used the fittings to make the necessary offsets to get around both the Aux. Vent and the drain stack. On the right hand side they could have done it simpler by just making one straight connection in the manner that I annotated as an option, but it really makes no big difference.

Now in regards to the pressure drop through the fittings.

The lines are supplying lavatories and the code madate for a lavatory supply is 2gpm. (That is the combined hot & Cold) so we design for a flow of 1gpm on each line.

Friction head loss is expressed in psi/100' of pipe and fitting insertion losses are expressed in the equivalent length of pipe that would cause the same friction as the fitting.

At 1gpm the friction head loss for 1/2" PEX is 1.61psi/100ft.

When compared to other types of pipe, PEX fittings have a very high insertion loss. By example, a copper 1/2" 90deg elbow has an insertion loss of 0.5ft, but a PEX 90deg elbow has an insertion loss of 9.4ft.

Looking at the worst case scenario here the lines on the right side have 5 90deg elbows so the fitting insertion loss is 5 fittings x 9.4ft per fitting equals 47ft of pipe and at 1gpm the friction head loss is 1.61psi/100ft or 0.0161psi/ft thus the total pressure loss through the fittings is 47x 0.0161psi = 0.75psi. Hardly worth even thinking about, especially when you consider that the code madated minimum supply for a lavatory is 8psi.

I do see a major code violation on that waste stack. The two fixture arms to the lavatories are tied into the waste stack by means of a double wye & 1/8bends. That is code prohibited. Code requires that they be tied in with a double sanitary tee.

I also noted that on both sides of the photo there are electrical cables running over the face of the studding. Those wires will need to be run through the studs before they can sheetrock.

    Bookmark   December 16, 2011 at 8:05PM
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a fixture cross is not a wye cross and not a double San-Tee cross.

a fixture cross is better than a double San-Tee cross. Both will drain.

Here is a link that might be useful: fixture cross image

    Bookmark   December 16, 2011 at 8:26PM
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OK. Thank you.

THe electrical wires are not really "in front" of the studs... The image is not clear- this is framing for our shelf above the faucets and the framing is not in line with the wall plane (just not so clear on the picture).

I learned about the fixture cross when I posted on the other forum...

Besides asking to correct the code vialation for drainage- what should we ask for in terms of delivery lines? Do not bother? I understood that the pressure loss will be minimal, but is this proper application of PEX plumbing?

PS. I am getting ready to ask for another plumber all together - am I unreasonable?

    Bookmark   December 16, 2011 at 9:00PM
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I don't care what you call it,,the fitting that is connecting the fixture arms to the stack will not pass code

    Bookmark   December 16, 2011 at 10:05PM
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efs, after you fix the DWV cross you will know whether you have people to rely on to redo the pex (which takes little time). Either way. If you needed an answer more urgently you would have gotten stronger urgings from everyone. The detailed information from lazypup is educational but doesn't say anything is so bad that it is important or urgent. Wait until you fix first the one thing that needs fixing. If that is easy or if that is like pulling teeth.

    Bookmark   December 16, 2011 at 11:33PM
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There is nothing technically wrong with that PEX installation other than the fact that it looks a bit amatuerish and if you are really intent of messing with it you could make that one change I noted on the PEX but, that would only give you a net gain of 0.3psi so at this point I don't think it would really be worth the effort.

Now in regards to the fixture cross. A fixture cross is nothing buy a variation of a sanitary cross (Double tee) where the top inlet and the two side inlets are smaller than the outlet....In fact, you could produce the same fitting using a 2" sani cross and installing 2" x 1-1/2" reducer bushings on the top and two side openings.

The fitting at the top of the photo where the two aux vents tie into the vertical riser is a sani-cross that is inverted, and when attaching vents it is required to be installed in that manner.

The fitting in the center of the photo where the fixture arms are attached is a double wye. Not that the side arms come off the fitting rising at a 45deg angle, then they installed 1/8 bends (sanitary 45 deg elbows) to turn the line to the horizontal plane.

Under the IRC the bottom of the fixture arm pipe at the trap weir may not be higher than the top of the pipe at the vent opening. (see attached illustration).

Now that is very important, because even though the code gives us maximum developed lengths for the fixture arms, that will only hold true if the fixture arm is installed with the prescribed 1/4" per foot pitch.

Under the IRC the maximum allowable length of the fixture arm is technically equal to the diameter of the pipe divided by the pitch of the run, thus if you were to install a 2" pipe with a 1/2" per foot pitch, the maximum allowable length would be 2" / .5 = 4'.

The fixture cross in the illustration is compliments of Harvel Pipe company, one of the leading manufacturers of plastic pipe and fittings.

    Bookmark   December 17, 2011 at 1:23AM
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Thank you very much... You made my day - I learned something new.

My major worry at this point is that this vialation is clearly visible, but if that was done incorrectly chances are that there are other mistakes that are less obvious.

I have A LOT of drainage going all around the first floor ceiling and I do not feel like taking pictures of every connection and asking you guys to tell me whether they are correct , i.e. legal (he was going down with pipes from the second floor and then realized when downstairs that these pipes need to make multiple turns before they land where they need to go, but was too stuburn to modify what has already been done upstairs to make the first floor piping less complex).

    Bookmark   December 17, 2011 at 9:10AM
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Good to check while you're checking: the upside-down double San Tee and the (perhaps) auxiliary vents. What are these connected to? I'd like to know a lot more about these vents. (Although vents are not bad, they are all good to have, good in every way, and one can never have too much venting). I'm just asking while the photo is there. The upside down c

    Bookmark   December 17, 2011 at 9:33AM
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"they used the fittings to make the necessary offsets to get around both the Aux. Vent and the drain stack."
It likely would have been better to go below and move where the lines come through the bottom plate so they are on the other side of the stack & vent when they come through the floor and bottom plate.

"There is nothing technically wrong with that PEX installation other than the fact that it looks a bit amatuerish'
It looks like 'on the job training' for a plumber experienced with copper, and they are doing a BAD job.

One of the advantages of PEX is that it IS flexible (within limits).
The jogs and stuff on the left are simply not required.
The PEX could come through the bottom plate at the same location and simply be routed to the final location.
there is plenty of distance to move it the few inches it needs to go without exceeding any bend rules.

The fewer fittings reduces the friction (and thus the pressure drop) since the PEX can be run in gentle curves.

    Bookmark   December 17, 2011 at 3:37PM
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Once again, you seem to be fixated on the pressure loss, but the resultant pressure loss is not enough to even be a factor here

    Bookmark   December 17, 2011 at 3:55PM
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but the number of unnecessary connections is a concern as a possible source of leackage.

I do not plumb houses but I do plumb PEEK tubing with unions and fittings for high pressure chromatography, so I know where leaks happen... not in solid piece of tubing (unless broken) while connections....

    Bookmark   December 17, 2011 at 4:14PM
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ditto: pressure loss is not a concern here.
ditto: if you choose to redo the supply lines it will be only because you want to run the line without "unions and fittings". Good for peace of mind. No one knows if it will spring a leak or not. There are unions and fittings all over the house, by the way. The more you think about it the crazier you can go. "You" means anyone, not the OP.

    Bookmark   December 18, 2011 at 9:12AM
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"Once again, you seem to be fixated on the pressure loss, but the resultant pressure loss is not enough to even be a factor here"

So the lack of pressure loss makes thie dumb use of excess fitting in a PEX instal acceptable?

Give me a break.

It looks like the amateur hour.
PEX is flexible.

Take advantage of it.

Every one of those joints is a possible source of a failure.

It does not mater how reliable the connection is, NO connection is more reliable (and cheaper).

There WILL be pressure loss from flow.
the fact it is not enough to interfere with minimum rules is not an excuse for what is in the picture.

A hack, at best.

Or is putting in excess joints OK as long as it meets the minimum flow at the end of the line?

    Bookmark   December 18, 2011 at 10:50AM
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