Pipe Freezing 101
Eliminate downtime, save money, and help the environment “We had a leak on a hot water return pipe and did not want to drain the system. By freezing the pipe, we were able to make repairs and have the system back up and running within one hour. Great service, fast and reliable.” ~ Newton Rajapakse – Chief Engineer, Terminal City Club Vancouver
Why do frozen pipes burst in winter? In winter ice forms inside the pipe and grows along the pipe when valves are closed tight. The ice expanding along the pipe presses against the water between the ice plug and the closed valve. Unlike air, water will not compress and so the pressure in the pipe rises. The ice continues to grow and press on the trapped water until the water pressure inside the pipe exceeds the pressurerating of the pipe and it bursts. In fact, it is water pressure that damages the pipe and not the ice. This fact is proven in the case where a faucet is left dripping. The pipe may still freeze in winter but it will not burst. This is because the water is not trapped and so an increase in pressure does not occur. The drip from the tap is relieving any potential build-up of pressure. In reality, however, a dripping tap may not save your pipes. Due to the uncontrolled nature of the freezing, there may be several pockets of trapped water which will cause damaging pressureincreases in multiple areas of the system.
What is controlled pipe freezing? Typically a containment unit is attached to the pipe and a refrigerant is passed through it. The freeze kit will uti46
Ops Talk • Fall 2013
