Burst Pipe?

The commonly held view that pipes burst when ice expands against pipe walls is not correct. In 1996, detailed research into the phenomenon demonstrated that bursting actually occurs when a solid plug of ice confines a volume of water, typically between the point of freezing and a fixture. Because the trapped water is uncompressible, the 9% expansion rate of ice can generate surprisingly high pressures – easily exceeding the 150psi design standard for water supply systems, and quickly surpassing the bond strength of joints and even the 3,000 psi burst strength of ½” copper pipes. (Gordon, “An Investigation into Freezing and Bursting Water Pipes in Residential Construction.”).