How Do Frozen Water Pipes Burst?

[SubLGT]

I always thought they burst at the point where the water is freezing and expanding. But in fact the damage occurs at a location between the plug of frozen water and a closed valve, because the water pressure increases dramatically as the ice plug increases in length. Pressure can go as high as 25,000 psi !!

https://www.thisoldhouse.com/plumbing/21133681/how-a-frozen-pipe-bursts

 

[weaponoffreedom]

Kind of true......................pipes burst due to pressure.........and where the weakest point is, as it relates to freezing. It is the pressure that causes the pipe to fail.

 

[Fitter30]

Water freezes expands 9%

 

[Cujet]

Maybe.

I've had to deal with many broken pipes from folks improperly winterizing a house. In that case, the low point where the 10 ounces of water remain is where the crack happens. Often at an elbow.

 

[PWMDMD]

Water is nearly incompressible as it’s already relatively “packed in” on a molecular level due to hydrogen bonding/dipole moment/104.5 degree bend. This is also why water is one of the few liquids that expands when it freezes (water molecules are no longer free to fit together as efficiently and as their kinetic energy decreases they assume a more orderly but less packed arrangement as a solid compared to it as a liquid). So it transfers nearly 100% of the force applied to it. So water freezes, it expands, applies pressure to adjacent liquid water, and pop.

 

[weaponoffreedom]

More respective to plumbing...................a hard pipe such as PVC or CPVC has little if any ability to expand, in contrast, type L soft copper can expand quite a bit before there is a rupture. If the pipe can expand relative to the freezing, there will not be a rupture. Where connections are made between pipes like copper and PEX, the junction between the two is very apt to failure due to freezing. At this point, pex is either compressed or expanded to close to its limits. Ruptures are common at these junctions.

Not to argue from a point of authority, but I am a licensed plumber in NC, and have got several calls about it today.

 

[LazyDog]

Pipes running through an outside wall or crawl space leads to all kinds of problems.

 

[Finklejag]

That’s why they say to keep one faucet dripping, it releases pressure in the line.

 

[ammolab]

Pipes running through an outside wall or crawl space leads to all kinds of problems.

Or a Texas attic!

 

[4wd]

Or a Texas attic!

Another comedian - disappointed I’m sure

 

[4wd]

That’s why they say to keep one faucet dripping, it releases pressure in the line.

Prevents freezing and resultant expansion

 

[ammolab]

Another comedian - disappointed I’m sure

What’s funny about your ceiling falling in as your Texas attic floods the house?

 

[4wd]

What’s funny about your ceiling falling in as your Texas attic floods the house?

Not my problem or yours

 

[4wd]

More respective to plumbing...................a hard pipe such as PVC or CPVC has little if any ability to expand, in contrast, type L soft copper can expand quite a bit before there is a rupture. If the pipe can expand relative to the freezing, there will not be a rupture. Where connections are made between pipes like copper and PEX, the junction between the two is very apt to failure due to freezing. At this point, pex is either compressed or expanded to close to its limits. Ruptures are common at these junctions.

Not to argue from a point of authority, but I am a licensed plumber in NC, and have got several calls about it today.

We have copper run between the ceiling joists and Sheetrock firring. Then R30 and 3/4” decking above. If it fails - yes it will damage Sheetrock and get fixed right there (has never happened to me) …
As stated in other threads - we don’t do basements with the soil and water tables here - foundation cracking and shifting is common - I don’t need underground/slab water leaks as part of that that mess …
Sheetrock is fixed cheap and quick - not foundational issues …

 

[andyd]

Maybe.

I've had to deal with many broken pipes from folks improperly winterizing a house. In that case, the low point where the 10 ounces of water remain is where the crack happens. Often at an elbow.

Once I got rid of an outdoor shower, my frozen pipe bursts ended. I've never tried it, but theoretically, I should be able to drain my house's plumbing from a hose cock between the pump and the tank. In the 45 yrs we've been here, we've never left for an extended time during the winter. I have a generator and a wood stove with a cord of wood less than 50 ' from it. I think I'm pretty well set for winter.

 

[brianl703]

Or a Texas attic!

A common thing in Virginia is to build a house with an overhang, and then put plumbing pipes in that overhang because the kitchen sink is above it. Those pipes will freeze.

 

[MikeT88]

Yeah, it’s really all about pressure and weak points in the line.
What a lot of people don’t realize is that when those pipes finally burst, the real problem isn’t just the pipe itself — it’s the water damage that follows. I’ve seen cases where a small rupture turns into soaked insulation, drywall, and even ceiling collapse if it’s not caught quickly.
Even in places like Las Vegas, where freezing isn’t common, similar pressure-related failures or leaks can still lead to serious water damage Las Vegas situations inside homes.
Once water gets loose inside walls or ceilings, it escalates fast, so prevention and quick response are key.

 

[Cropduster172]

We made it through this winter with no frozen pipes at our beach house.
There's quite a bit of copper pipes in the crawlspace.
This coming fall installing this electric pipe tape is a planned project.

https://a.co/d/0dMrpFaZ

 

[Pablo]

I love me some shredded PVC pipe in January!!