Ice I-II-III

[Norman Albers]

How can I calculate the force with which freezing water, caught with no expansion exit, wrecks water pipes and fixtures not well designed for such temps and pressures?

[iNow]

You'd probably have to know:

 

The pressure of the water in the pipe (if the pipe is not completely filled to the brim with water, then clearly a freeze will not have as much explosive force on that pipe as one that has little to no air... only water from top to bottom).

 

You'd need to know what pressure the pipe can withstand, and factor in the years of degradation and erosion and any faults that happened when they were installing and if the earth has moved since the install and... ellipsis other faults that could have become part of the pipe system.

 

You'd need to know how that variable amount of water in that pipe of unknown construction was reacting to the slowly decreasing outdoor temperature, and ... well...

 

 

It'd be a very "fuzzy" guesstimate more than an hard and solid data point. It's not like "Pipes will burst = x + 7 x 5t..." There are too many unquantifiable variables, and those you can quantify are likely to be pretty error ridden.

 

 

I'm not mathemagician though... so don't rely too heavily on my word for this one.

 

 

Would pouring Irish Whiskey down the drain keep them from freezing? I know it warms me up on a cold night, but pouring it down the drain would be sacrilage.

[scalbers]

From this page it appears to be a complex determination...

 

http://www.newton.dep.anl.gov/askasci/eng99/eng99530.htm

[Norman Albers]

Physical chemistry is cool. I got out the phase diagram. Going downward from zero degrees C., the phase boundary of ice I with liquid has a negative slope of about 200 atm. per degree, saying that if at -5 degrees you apply one thousand atmospheres pressure, you'll prevent freezing. This I think is a certain upper limit, but it gets rapidly out of hand. Given a roughly nine percent expansion (density of ice is 0.917 gm/cc), the datum I cannot find is a Young's modulus of compressibility for ice I. FURTHER PHASE PHUN: At about 2047 atm. and -22 deg., you get ice III phase state. Lower the temperature to -34.7 deg. and you get ice II.

[YT2095]

I actually tried this myself a few times also.

 

I used a .22 gun barrel, 1`st time I tried it popped the one end out (solder plug), the next time I tried Welded, I have no idea what happened, I didn`t figure out a way to get to the Ice(n) after to examine it *sigh*

 

needless to say, it needs something Much More elaborate than a simple gun barrel sealed off and put in the freezer!

 

you need some sort of well sealed thick walled container and a walk in freezer to extract it in.

 

 

live and learn

[Skye]

The metal that is used is important too, because at the temperatures you are talking about they may behave in a more brittle manner, and fail unexpectedly. Metals that have a body centred cubic crystal structure, such as some steels, will do this. Copper pipe though, probably wouldn't, at least it's more likely to be predictable.

[scalbers]

Here's an excerpt from the website I mentioned above that mentions the bulk modulus:

 

----------------------------------------------------------------------------

 

The bulk modulus of ice is about 8.8E9 pascals. That means that if you completely froze the ice cube (let us say, pretty cold), and tried to stuff it back into the box, you would need to squeeze with a pressure of about 790 megapascals of force to compress 9% to make it fit. That is about 114,000 pounds per square inch, so you would need a strong box. But during the process of compressing it into the box, the pressures would be high enough for the ice to transform to types 3 and 5 and maybe even 6. It is difficult to determine what the compressibility of these ice forms are. So, as the ice is squeezed into the box (or as it is made cooler and cooler), it takes a real expert to figure out what the pressures are. But, solid ice is ALWAYS the stable phase of water at about –20C and below, so that the water in the infinitely strong and rigid cube will indeed freeze.

[Norman Albers]

Aha, thank you scalbers. I figured very high pressures were manifest here, way past splitting steel plumbing pipes, let alone fixtures. I am entertained to watch a neighbor who repeatedly broke faucets and gatevalves in freezing at a barn, now has left a one-meter high exposed straight 3/4" pipe with a threaded cap. Most of it has insulating collar, except the top few inches. I figure that there may be relatively warmer water in the supply pipes below, depending on usage moving water through. Our nights have been 24 F. Now practically speaking, I figure there is freezing from the outside in, so maybe the first thickness can deform inward. Only when the "gun is welded" as per YT, in this case freezing solid at some point, is the entrapped water forced. I'm hoping the pipe splits.

 

The metal that is used is important too, because at the temperatures you are talking about they may behave in a more brittle manner, and fail unexpectedly. Metals that have a body centred cubic crystal structure, such as some steels, will do this. Copper pipe though, probably wouldn't, at least it's more likely to be predictable.

 

Skye, this is an interesting offering. I think of steel as microcrystal mixture, so what exactly is cubic crystal, the dominant phase? Copper will certainly stretch more.

[Skye]

Norman, yes, the dominant phase in low carbon steels (ferrite) has a body centred cubic (bcc) structure. This refers to the arrangement of atoms in the crystal. All metals display increasing brittle behaviour at lower temperatures, but there is often a dramatic change over a small temperature range. This is called the brittle-ductile transition. This is more of an issue with bcc metals, as the transition occurs at higher temperatures and it is more pronounced.

 

An interesting application of this was that the ship steels used a century ago had higher brittle-ductile transition temperatures, which has been put forward as contributing to the Titanic sinking:

 

http://www.tms.org/pubs/journals/JOM/9801/Felkins-9801.html

[Norman Albers]

Nice addition, Skye, I did not know about that transition.

[Norman Albers]

In their Jan. 26 issue, Science News states: (p. 58) "...density at low temperatures. While other liquids contract and get denser as they cool toward their freezing points, water stops contracting and starts to expand. That's why ice floats and frozen pipes burst." NO, NO!!! It is true that water reaches it's max density at 34 deg.F and is slightly less dense at 32. This has not much to do with freezing per se.