# Large Storm/DWV System Testing?



## Mathyou (Oct 20, 2011)

If you had to stack test a 5+ story Storm or DWV system that had long runs of 10" and 12" no-hub what would be your approach?

A standard "fill with water and wait" test can be very impractical in certain situations. It is very time consuming, it can blow-out no-hub bands if the base of the test has enough head pressure, and you have to flush the test and winterize traps in cold weather.

Anyone have experience with smoke test equipment? I was never sold on the peppermint test.


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## surfdog (Oct 20, 2011)

new building not sure what you mean by storm


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## Mathyou (Oct 20, 2011)

surfdog said:


> new building not sure what you mean by storm


Downspouts...


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## Tommy plumber (Feb 19, 2010)

(1) floor at a time, don't try and fill 10" diameter pipes all (5) floors at once. Is that what you're asking?


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## PrecisePlumbing (Jan 31, 2011)

Air test


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## surfdog (Oct 20, 2011)

test ts floor at a time


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## plbgbiz (Aug 27, 2010)

^^^

Isolate the floors and smoke each one individually.

You could air test but that will only verify the existence of a leak. It won't lead you to the source.


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## SlickRick (Sep 3, 2009)

5 story bldg, 12" pipe. How much force would be applied against the test ball or plug?


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## Tommy plumber (Feb 19, 2010)

SlickRick said:


> 5 story bldg, 12" pipe. How much force would be applied against the test ball or plug?


 




Maybe that Swede fellah can answer for us.....:laughing:


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## SlickRick (Sep 3, 2009)

PipeRat could if he were here, it would be substantial.


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## Tommy plumber (Feb 19, 2010)

SlickRick said:


> 5 story bldg, 12" pipe. How much force would be applied against the test ball or plug?


 




That's actually a state plumbing exam question, excellent question by the way Rick.

psi=Height x .434
psi=50' x .434
psi= 21.7

A (area of plug)
A=3.1415 x plug radius. x plug radius
Let's assume the radius of a 10" plug is 5"

A= 3.14 x 5" x 5"
A=78.5 sq. inches

Total pressure= psi x area
TP= 21.7 x 78.5"
TP= 1703.45 pounds

( I think, feel free to correct or critique)


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## SlickRick (Sep 3, 2009)

Tommy plumber said:


> That's actually a state plumbing exam question, excellent question by the way Rick.
> 
> psi=Height x .434
> psi=50' x .434
> ...


Good job Tommy. We had a good thread on force awhile back.

I had to test a 12" roof drain system through the roof, out to the curb on a 2 story bank ( engineers specs.) I had a backhoe bucket holding the wing type test plug in. It was pushing hard against the bucket. When I let it go, It almost washed the road out.


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## Tommy plumber (Feb 19, 2010)

I must confess I peeked at my plumbing book...:whistling2:

I forgot head was .434 :laughing:

I knew head pressure was height x something, but I forgot the something!......:laughing:


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## TX MECH PLUMBER (May 27, 2011)

I tested a San and storm drain with smoke not long ago !!! On a 150 ' tower !! I put smoke bomb in line at man hole and used a small fan with some flex ( duct) to push the smoke up !! It took several smoke bombs though!! Is this for a city inspection or gc ??? I used cantex caps to cap off lines!! My test was for gc and FAA My apprentice put smoke in and we observed smoke at vents on 1 story roof then capped lines, then went 8 floors up (150') and capped of the last vent!! Then walked entire building!!! If you must water test then like stated above you must break it up in sections!!! And it's very time consuming!!! An air test is hard to pinpoint leak unless you smoke it and then pressure it up, also be careful what pressure you put on it.. I think UPC states 5 psi!! Max because PVC with explode like a bomb and ci can too!! Good luck !! Smoke is the fasts way to go!!!


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## BROOKLYN\PLUMB (May 21, 2010)

Tommy plumber said:


> That's actually a state plumbing exam question, excellent question by the way Rick.
> 
> psi=Height x .434
> psi=50' x .434
> ...


 The pressure at the base of the stack would be constant no matter what size the pipe or cap is

So what I'm not understanding is how the 1703.45 psi comes into play, are you saying that a fitting at the base of a full 12" stack is seeing pressure like that?


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## Master Mark (Aug 14, 2009)

I dont remember the head pressure, or the 
weight of water in a tall , long line like that

but the only thing I DO remember and I will never 
forget is to never get your hand stuck in the pipe when 
you let the air out of the test plug....:laughing::no::no:


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## BROOKLYN\PLUMB (May 21, 2010)

The Peppermint test is the fastest just might be longer if you have to find a leak. But how many of you guys fail your tests? And if so why? what kind of material? or just stupid mistakes?


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## TX MECH PLUMBER (May 27, 2011)

BROOKLYN\PLUMB said:


> The pressure at the base of the stack would be constant no matter what size the pipe or cap is
> 
> So what I'm not understanding is how the 1703.45 psi comes into play, are you saying that a fitting at the base of a full 12" stack is seeing pressure like that?


He is saying if you filled the w line with water that would be the pressure !!! How can the pressure be constant?? Larger pipe = more volume of water = more weight on base of stack!! Rite???


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## Tommy plumber (Feb 19, 2010)

BROOKLYN\PLUMB said:


> The pressure at the base of the stack would be constant no matter what size the pipe or cap is
> 
> So what I'm not understanding is how the 1703.45 psi comes into play, are you saying that a fitting at the base of a full 12" stack is seeing pressure like that?[/QUOTE]
> 
> ...


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## TX MECH PLUMBER (May 27, 2011)

So if you put a gauge on the cap you would get that pressure??


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## Tommy plumber (Feb 19, 2010)

TX MECH PLUMBER said:


> So if you put a gauge on the cap you would get that pressure??


 




No. It's the total force in pounds on a 10-inch diameter brass plug with a water head of 50 feet.

The pressure at base of stack, as someone already pointed out is 50' x .434 which =21.7 psi; and the volume of water does not change the psi at bottom of stack, but the volume definitely increases the total force at base of stack.


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## TX MECH PLUMBER (May 27, 2011)

Tommy plumber said:


> No. It's the total force in pounds on a 10-inch diameter brass plug with a water head of 50 feet.
> 
> The pressure at base of stack, as someone already pointed out is 50' x .434 which =21.7 psi; and the volume of water does not change the psi at bottom of stack, but the volume definitely increases the total force at base of stack.


I don't get how the volume would increase 
Force but not psi. What do you mean by force ?? I'm tryn to soak all this up. Thanks !!


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## Tommy plumber (Feb 19, 2010)

I mis-spoke when I typed 'total pressure'.

Regardless whether it's a 6" diameter stack or a 24" diameter stack, the pressure is the same at the base. The total force in pounds increases with more water, but the pressure doesn't increase, only the volume does.





edit: I typed 1703.45 psi in an earlier post; it should've been 1703.45 pounds, sorry for the error.


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## OldSchool (Jan 30, 2010)

Is that in US gallons or Canadian gallons :blink: :laughing:


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## sidekick (Nov 29, 2011)

*smoke vs. water*

You may want to check things out with the Authority Having Jurisdiction ask what they suggest. I’m thinking that a smoke test will diffidently identify your leaks but it doesn’t give you your head pressure test that is required for inspection


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## Mathyou (Oct 20, 2011)

This was a hypothetical situation. In the past I have run tests like this where I isolated the stack test to 2 floors at a time. That process requires a ton of extra test tees, even if they were bid or not that can be a lot of money in test tees alone. Not to mention a lot of man hours in testing that way... and like I said the problems with winterizing traps in cold weather as well.

I have ran a smoke test before... we had a legit machine that was designed for testing as well, not the jimmy rigged smoke bomb and fan test like someone suggested. Did not work very well at all.

An air test would not work in a situation like this, putting even 7 psi in a system of that size would cause no-hub bands to blow out.

Just trying to find out how some of you guys go about large scale testing.


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## PrecisePlumbing (Jan 31, 2011)

I said air test because that would tell you if you had a leak to begin with and is rather easy to set up. It gives you a direction to go to either the test passes and it's sucessful or it fails and you then go to smoke testing or single level water testing. I find it amazing systems are being used that would blow out at such low pressure. There is nothing on the market here that would not take 300 kpa no problems


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## Redwood (Sep 8, 2008)

Tommy plumber said:


> I mis-spoke when I typed 'total pressure'.
> 
> *Regardless whether it's a 6" diameter stack or a 24" diameter stack, the pressure is the same at the base.* The total force in pounds increases with more water, but the pressure doesn't increase, only the volume does.
> 
> edit: I typed 1703.45 psi in an earlier post; it should've been 1703.45 pounds, sorry for the error.


The difference is between "Pressure" & "Hydraulic Force"

How can a 2,000 psi hydraulic system generate 40,0000 pounds of force?
Use a 5" Cylinder...:laughing:


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## SlickRick (Sep 3, 2009)

One of our best threads IMO...

http://www.plumbingzone.com/f2/psis-relationship-pounds-force-6665/


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## Pipe Rat (Apr 5, 2009)

Tommy plumber said:


> I mis-spoke when I typed 'total pressure'.
> 
> Regardless whether it's a 6" diameter stack or a 24" diameter stack, the pressure is the same at the base. The total force in pounds increases with more water, but the pressure doesn't increase, only the volume does.


 
Here we go again LOL :laughing:

Your on the right path Tommy but the force AND the pressure increase together. The force pushing against the plug is directly related to the PSI not the volume of water.

A 12" dead level pipe 100 feet long filled with water will have a psi of only .434 lbs and 49.05 total pounds of thrust or force trying to push the plug out.

The same 12" pipe stood vertically (100 feet tall) and filled with water will have a psi (at the bottom of course) of 43.4 lbs and 4,905.93 total pound of force.

You can also take a one foot piece of pipe and pump it up to 43.4 psi and have the same forces present. :yes:


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## Widdershins (Feb 5, 2011)

Mathyou said:


> Just trying to find out how some of you guys go about large scale testing.


 Popping a 5 story test and then having to refill it because of a single leak on the fifth floor could be costly and time consuming.

I would isolate each floor with a clean-out tee, a Cherne Clean-Seal and a means to drain down each floor individually.


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