In a nutshell, when water in pipes freezes it expands and causes an increase in water pressure which in turn causes the pipe to burst. This condition is frequent in cold conditions making it more frequent in the cold regions in the world. This frost conditions do not only affect the pipes but the pump as well. They may lead to electrical or fuel complications in pumps.
Why do pipes burst?
It is easy to assume that the pipes burst due to the radial pressure caused by the frozen water (ice) in pipes but it is not the case. In fact the pipes rarely burst where there is ice within the pipe. So this is what happens: when there is a complete ice blockage, the pressure of water between the blockage and a closed tap increases. The pressure increase is usually caused by the alternate contraction and expansion of the pipe due to freezing and thawing. This high amounts of pressure is what causes the pipe to burst downstream where away from the frozen blockage.
Contraction caused by the cold results to stress and strain on the joints and other weak points of the pipes which in turn leads to leakages. In such cold conditions locating and repairing of those leaks in a big challenge due to the following reasons:
In normal conditions when water in pipes leaks, it flows to the surface close to where the water problem is emanating. In frozen conditions, the cap of frozen ground may force the leaking water to flow horizontally and surface far away from the leaking pipe making it difficult to locate the leakage.
Use of leak detection equipment such as aquaphones and geophones is hampered by thick caps of frozen ground.
Preventing bursting of pipes due to freezing
Draining faucet-stands and distribution pipes. Water can be drained into reservoir when the flow in the pipes is not continuous especially during the night and taps to be left open to drain any water left in the distribution system. Design features of the distribution system such as a perpendicular air inlet pipe after the outlet gate controller of the water storage reservoirs and washout valves at low points of the distribution system may come in handy.
Sustaining a continuous flow. This can be done by recirculation or leaving the taps running at distribution points. The latter option is wasteful and can only be used as a temporal measure.
Pipe burial. Ensuring that most pipework is done underground in areas where the ground is not permanently frozen can reduce freezing and bursting of pipes. The depth of such pipes should be greater than the expected depth of frost penetration.
Pipe insulation. This method is usually coupled with pipe burial to supplement each other.
Defrosting of ice-blockages in pipes
An electric currents can be employed for this function in small diameter pipes. Welding machines, generators or heavy service transformers are normally used for providing such current.
Use of hot water. This can be applied to both plastic and metallic pipes. It is a simple method whose main principle is to melt ice using hot water.