From – 2.5ºC rising to + 4ºC; this dramatic rise in temperature over 2 hours on the morning of 9th January allowed frozen pipes to suddenly thaw. Result: devastation.
Copper pipes split where the frozen water contained within expanded and ruptured the metal. With the thaw water is pressurised out of these splits at speed. The hissing noise is usually the first indicator something is wrong.
The other point of failure can be at joints where pressure from frozen water pushes the end of the pipe out of its connecting olive. Again, all will look normal until the thaw.
An outside tap is a boon to the gardener but relies on good lagging and ideally a stop cock inside the house where it can be turned off and then this section of pipe drained before the first frosts. Still and standing water is more likely to freeze in pipes than water moving as taps are opened to draw some off. On the pipe work at the right angle as it rises to the outside tap, if well installed, is a small square headed grub nut. By opening and removing this all water will drain from the pipe. Result: peace of mind.
This year make a point of lagging all outside pipe work and all pipe work in your home that is on outer walls. Pay attention to joints and changes of direction in the pipe work where you will need to bind pieces of lagging to cover all gaps. No bare pipe work should be exposed to the elements.