# CPVC expansion loops



## track3 (Dec 31, 2011)

The mech engineer specked the water main for a hotel as 4" CPVC and wanted them every 30 feet. Apparently every 100 ft. of hot can expand up to 4 inches.

The schedule 80 stuff is also quite spendy. So, why use the stuff on a building over 300 ft. when you can have 12 inches of potential shifting.

Seems aquatherm would be a much better choice for a main. And then run uponor off of it. 

So how does everybody else run their mains for large apartments and hotels?

Seems the possibility of copper thieves has made it an obsolete material except in certain instances.


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## Greenguy (Jan 22, 2011)

we just install a proper sized expansion tank. that said most of our mains are either copper usaelly using Vict fittings, makes for ease of expansion.


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## Tommy plumber (Feb 19, 2010)

track3 said:


> The mech engineer specked the water main for a hotel as 4" CPVC and wanted them every 30 feet. Apparently every 100 ft. of hot can expand up to 4 inches.
> 
> The schedule 80 stuff is also quite spendy. So, why use the stuff on a building over 300 ft. when you can have 12 inches of potential shifting.
> 
> ...


 





Might want to read up on all the different substances that erode or degrade CPVC. It is one long list. Lots of plumbers steer clear of it. Or is this job a case of 'It only has to last a year, then it's Habeeb's problem.'........:laughing:


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## tungsten plumb (Apr 15, 2010)

Tommy plumber said:


> Might want to read up on all the different substances that erode or degrade CPVC. It is one long list. Lots of plumbers steer clear of it. Or is this job a case of 'It only has to last a year, then it's Habeeb's problem.'........:laughing:


Don't you mean Mr. Patel:laughing:


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## RealLivePlumber (Jun 22, 2008)

What difference does an expansion tank make?

The pipe will still expand and contract in length, from changes in water temp, as well as ambient.


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## plbgbiz (Aug 27, 2010)

Coefficient ratings are based on temperature changes. The coefficient for CPVC is not just 4" per 100'. It is 4" per 100' per 100 degrees of temperature change.

Assuming a couple of temps here...

Let's say the incoming water temp in the winter when you install the service is 40deg and next summer it will be 80deg.

300' of PVC will expand 4.176"

If the water starts at 40deg and only heats up to 70deg it expands to 3.132".

4" expansion per 100' is based on a temperature rise of 100 degrees. I doubt that is going to happen on your water service.

Here's a thermal expansion calculator. >> http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.html

Enter .000029 in box (a) for PVC. I'm still looking for the number for CPVC.


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## plbgbiz (Aug 27, 2010)

Found this>>> http://www.kthsales.com/website/vendors/spears/PDF/Expansion-Joints.pdf

In the document it states the following: _"...for CPVC, allow 1/2” expansion for every 10°F change in
temperature per 100’ of pipe (regardless of diameter)."_

So if the temperature rise is 50 degrees on 300' of pipe, it will expand a total of 7.5 inches.

Their expansion joints look like the cat's meow for your situation.


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## track3 (Dec 31, 2011)

plbgbiz said:


> Found this>>> http://www.kthsales.com/website/vendors/spears/PDF/Expansion-Joints.pdf
> 
> Their expansion joints look like the cat's meow for your situation.



That does look like the cat's meow. Thanks for that info.


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## track3 (Dec 31, 2011)

Tommy plumber said:


> Might want to read up on all the different substances that erode or degrade CPVC. It is one long list. Lots of plumbers steer clear of it. Or is this job a case of 'It only has to last a year, then it's Habeeb's problem.'........:laughing:


I'm well aware of the problems of the smaller garbage. It's what the engineer wanted and only for the mains and recirc line. We run uponor off of that. I

That said the bigger schedule 80 grey stuff for hot is some heavy duty stuff. It's more having so many expansion loops is a pain and gets expensive at $150 a 90.


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## surfdog (Oct 20, 2011)

do as the engineer wants


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## Widdershins (Feb 5, 2011)

surfdog said:


> do as the engineer wants


 Exactly. CYA.


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## plbgbiz (Aug 27, 2010)

track3 said:


> ...and gets expensive at $150 a 90.


Not your problem. You didn't hire the engineer.


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## Pipe Rat (Apr 5, 2009)

Bid and install per spec. CYA. Who cares if the 90's are $150 apiece, if everyone is bidding to the same spec?


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## Mississippiplum (Sep 30, 2011)

Cpvc Is shiot. Alot of products cause that stuff to weaken, including alot of cleaning chemicals. 

But it's the engineers decision. Copper would be a much better choice and might even be cheaper.


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## Tommy plumber (Feb 19, 2010)

surfdog said:


> do as the engineer wants


 





Yep. If the prints are signed and stamped by the engineer/architechtural firm and the prints have been approved from bldg. dept. after having gone through plan review, then it is their call.


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## Qball415 (Nov 20, 2010)

Most of us know this...but, check dates on all the drawings. 
Read every single word in them too.


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## RealCraftsMan (Dec 27, 2011)

Mississippiplum said:


> Cpvc Is shiot. Alot of products cause that stuff to weaken, including alot of cleaning chemicals.
> 
> But it's the engineers decision. Copper would be a much better choice and might even be cheaper.


 
The last 3 or 4 big jobs we have done have had the engineers going with cpvc. Its had us scratching our heads, could it be copper thefts are at an all time high in Houston?


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## Mississippiplum (Sep 30, 2011)

RealCraftsMan said:


> The last 3 or 4 big jobs we have done have had the engineers going with cpvc. Its had us scratching our heads, could it be copper thefts are at an all time high in Houston?


It has me scratching my head too, so much most of my hair is gone.


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## OldSchool (Jan 30, 2010)

Greenguy said:


> we just install a proper sized expansion tank. that said most of our mains are either copper usaelly using Vict fittings, makes for ease of expansion.


Now that is just silly :laughing:


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## Greenguy (Jan 22, 2011)

Lol I know should see some of the fukin crap I have to install, only been doing federal jobs lately getting tired of having to figure out what 6850mm is in inches. And I we want to change anything I have to submit my idea back to the mechanical engineers to sign off on. Most jobs seem to be SNC Lavalin crap.


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## ZL700 (Dec 8, 2009)

Greenguy said:


> we just install a proper sized expansion tank. that said most of our mains are either copper usaelly using Vict fittings, makes for ease of expansion.


Green guy, is there a instruction book you have available showing what size tank or how many you need to install per foot to keep the pipe from expanding? :laughing:


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## Greenguy (Jan 22, 2011)

Yup I do it’s can an RFI (request for information) I kick it off to the engineer and let them deal with it, takes about 20 minutes of my time, if it’s wrong, well its installed to spec and i lose no money, and can book it as an extra to fix.


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## U666A (Dec 11, 2010)

Greenguy said:


> Lol I know should see some of the fukin crap I have to install, only been doing federal jobs lately getting tired of having to figure out what 6850mm is in inches. And I we want to change anything I have to submit my idea back to the mechanical engineers to sign off on. Most jobs seem to be SNC Lavalin crap.


If it's not Lavalin, it's PCL!

If it's not PCL, it's Ledcor!

If it's not Ledcor, it's Ellis Don!

If it's not E.D., it's V.K. Mason!

If it's not V.K.M., it's Kiewit!

If it's not Kiewit, it's Ontario Power Generation!

If it's not O.P.G., it's Ganotec!

They all say they want me to go home to my family every night, but that only applies so long as I install footage! What gets them off, is passing the buck and playing the blame game towards those lowest on the proverbial totem pole. These are usually the ones who depend the most on the job, and are often fired for following directions perfectly... apprentices are a common casualty


B.T.W... I don't know how many of those y'all have heard of, but they're mostly owned by one of the above listed conglomerates, and are all fronted by the carbon copy sheep in wolves clothing on a Jobsite level...

It's a shame, but I've developed an astonishing level of contempt for any figure in a middle to upper echelon of construction management amongst the higher tiered contracting firms of which I've had the "privilege" of being sub-contracted by...

I feel better, do you?!?

I know Kung Fu!


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## Greenguy (Jan 22, 2011)

Lol so true, I'm working on two PCL jobs right now and have another 4 Graham sites on the go, all 6 have prints and spec's put out by Lavalin. Be glad when I can go back to service, 1 of the Forman in my service dept wants me to sign on for refridgeration apprenticeship, could be fun and would get me outa the crap jobs.


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## Greenguy (Jan 22, 2011)

Back to OP not being a PVC user do you generally have to make any significantly different changes as opposed to using copper?


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