Pipe Least Likely to Burst in Freezing Temperatures

[kirkz]

Once the subfloor/durock/tile goes down in the small bathroom I'm renovating there will be no access to the pipes under the floor. I live near Erie, PA so winter temps can be very low. There is a shallow unheated space under the floor which is sealed off from the weather. The bottom of this space is a concrete slab. Floor joists rest on this slab. Insulating the pipes is a given but which pipe has the most burst resistance? Type K copper? Schedule 40 Stainless? PEX Tubing? Schedule 80 CPVC? Thanks in advance!

 

[LSThill]

Case 29: Pressure Buildup in a "blocked-in pipe:

Hydrocarbon Processing, October 2005 Page 111

Liquid thermal expansion can rupture pipes

You must read and review!!!!

 

[TBP]

Many brands of PEX can be frozen 3 or 4 times before they actually split. On the other hand, PEX can be gnawed through by animals. What does your plumbing/building code say about installations like this?

 

[RJB32482]

ISthill, do you have ths article to send?

Thanks

 

[MikeHalloran]

It _will_ freeze, and eventually it _will_ burst.

I'd consider installing a bent tube, through which I could snake the occasional replacement hose.



Mike Halloran
Pembroke Pines, FL, USA

 

[CarlB]

HDPE is resistant to damage upon the contents freezing solid and expanding. This is one reason HDPE is the material of choice for arctic water and sewer systems. Some information in

http://www.cpchem.com/enu/docs_pipe/PP501WaterDistribution.pdf

 

[LSThill]

RJB32482 (Chemical)


Case 29: Pressure buildup in a ‘blocked-in’ pipe
Liquid thermal expansion can rupture pipes
T. Sofronas

http://www.hydrocarbonprocessing.com/

 

[rconner]

CarlB,
What a warning (to design to?) at the end of the following bolded caveat on page 3 of the document your link points to! (also in same, is it possible "can be" is sort of misleading? -- can pipe withstand indefinite cycling of freezing as it appears might be read by some into this? -- with what length freeze plug and what degree of say endwise confinement? -- what is the specific dimensional and material property/fracture mechanics definition also of "without damaging"?):

"Water can be frozen solid in polyethylene pipe without damaging the pipe, but an ice plug in the pipe will stop flow. Do not apply pressure to a frozen line that has an ice plug. Allow ice plugging to thaw before applying pressure to the line. Severe water hammer (such as from an ice plug stopping suddenly at an obstruction) in a frozen, surface or above grade pipeline can shatter the pipeline and flying fragments can cause death, injury or property damage."

[Frankly, if I had to design a pipeline to provide for specifically for freezing, I'm not sure I don't like better Mr. Halloran's idea of what would appear to be a protective/perhaps even insulating to some extent? casing in an inaccessible area, perhaps even with some sort of double pipe leak monitoring if advisable, or at least casing interstice drain to an area that will not damage if the carrier pipe were to develop a leak, that additionally might allow for more ready repair/replacement of the line if necessary?]

 

[mshimko]

Mountain cabins, especially those used primarily for vacation/weekend use, are often elevated with unheated areas under the cabins. Water piping runs from underground into the cabins, passing through an unheated space.

Use of pipe heaters (with or without thermostatic contril) is common on these cabins. Have you considered it for your application?

 

[kirkz]

Thanks to all for your input. Carl B's HDPE inside Mr. Halloran's bent tube sounds like a pretty foolproof approach albeit a bit tricky to implement. Mshimko, I'm
trying to stay clear of anything that could fail like heat tapes as there will be no access to these pipes once my subfloor goes down. I'm still hoping to hear the definitive answer to the question in my original thread:
Which of the pipes I mentioned is least likely to burst in freezing temperatures?

 

[MikeHalloran]

I'd guess the HDPE.

But I don't know of anything that will take repeated freeze/thaw cycles indefinitely.

Better to erect passive defenses, like evergreen shrubbery around the house.



Mike Halloran
Pembroke Pines, FL, USA

 

[PEDARRIN2]

Make sure you look at your plumbing code.

The IPC doesn't allow HDPE for domestic water piping.

 

[kirkz]

Thanks PEDARRIN2 for the IPC information. It's looking like PEX tubing might be best here. I'm considering an outer "conduit" of 3/4" PEX (insulated) with a 1/2" or 3/8"
PEX tubing inside. I'll make individual runs to the fixtures (bathtub, sink, toilet) to eliminate any joints under the floor. Sound like a plan?

 

[cvg]

constructing your bathroom with "no access" is not recommended as eventually the pipes will leak and then you will have a real mess on your hands. Why can't you just put in an access panel either in the bathroom floor or elsewhere to provide an easy way to get between the subfloor and the ground?

Domestic water pipes are often installed under concrete slabs here in Arizona - and even though they don't freeze, they still spring the occasional leak, regardless of what type of pipe material used. The solution is get out the jack hammer and destroy your bathroom floor to get at the leaky pipe! A basement or a crawl space with access would solve the problem.