Re: Use of ice to plug a pipe

> Moral - you can use a freeze stopple, but DON'T close the block valves
>(or have a relief valve that will bleed off the pressure). I think that's right. I once spent a very interesting hour or discussing how all the damage might have unfolded, including the toilet tank rupture and the ensuing water damage which was total. We concluded that the pipes broke when a plug trapped some water, either by a closed valve or another ice plug it did the deed as it expanded. The freezing plug doesn't split the pipe because it doesn't expand radially--all the expansion is streamwise because the maximum volume occurs while the water is still a liquid, and the ensuing pressure in the trapped liquid applied the hoop stress which splits the pipe. The toilet tank froze from the top because ice floats and that's what trapped the water inside until the pressure broke the ceramic tank wall. At some point the house warmed up enough to loosen the upstream plug and water flowed in (and out) through the ruptured piping.

It was such a neat little grandmother-looking house from the outside, and so totally trashed inside. Two of us wandered through finding weird stuff like half a split pipe elbow resting on a radiator, the broken toilet tank, pipe runs with several splits, cracked radiators and fittings. I've seen some busted piping over the years, but never in such an innocent setting.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)