"Edwin Pawlowski" wrote in message
...
"jack" wrote in message
Sealing the top doesn't seem right. The one time I had broken pipes,
they were drained, but there was some residue left in low spots. They
had plenty of room to expand into.
I thought a better test would be to put a right angle bend on the pipe;
then fill it and let it freeze. The right angle would reduce the ice's
ability to expand, and would be pretty much like real plumbing.
4 hours at zero and it didn't do anything but freeze. It didn't even
swell.
Apparently my simulation is deficient. Maybe the bottom of the L has to
be much longer?
If you don't seal the water in some manner it will move to the outside and
not exert pressure on the tubing walls. The water in low spots of your
pipe is a different scenario of a test pipe in the freezer. At some point
the water at the ends freezes and makes a plug. Later the center freezes
and exerts pressure in all direction but since the shallow water at the
ends froze first, it can burst the tubing.
You may find this interesting too. Hot water pipes can freeze before cold
water pipes.
http://www.gi.alaska.edu/ScienceForum/ASF4/440.html
As an aside (something probably totally irrelevant and not to do with this
discussion), I have seen and fixed LOTS of spindles in ornamental metal
railings and fences that were burst from freezing. When constructed, the
ends were not welded totally shut, and water infiltrated from somewhere. It
is amazing to look at these burst tubes, as they are burst in all places.
At the top, the bottom, in the middle, everywhere. One would think that the
water would migrate to the low point, and freeze there. Yet there are
obvious bursts in the middle of six foot sections. Maybe that's just the
point at which it started freezing after filling the tube half full. And
this was in the temperate climate of Las Vegas, and it's not that cold
there.
Point is, freeze bursting may be totally predictable and scientific and
explainable, but from my observations, it burst in some pretty weird places.
Steve