Pipe Freezing

Pipe Freezing is an effective and efficient method of isolating sections of pipe for repair and maintenance, valve replacements etc. This is done by freezing the contents of the pipe to create an internal ice plug. This eliminates the need to drain long sections of pipe and reduces shut-down time. Pipe Freezing or “Ice Plugging” was first used by the US Navy in the 1940’s and is now a common practice in building maintenance and countless applications in the piping industries


COB Industries, Inc. first introduced the Qwik-Freezer® kits over 30 years ago and there are now thousands of kits in use around the world. Qwik-Freezer® is a portable, affordable and effective liquid CO2 system with kits available for up to 8” pipe. Qwik-Freezer® is used by plumbing and maintenance contractors, power plants, water utilities, the US Navy, etc.


The patented Accu-Freeze® liquid nitrogen system was created to meet a specific need in the nuclear industry for “controlled pipe freezing”. In other words, the ability to freeze pipes to create an ice plug while controlling the temperature that the pipe wall is subjected to. Accu-Freeze Kits include a digital controller and a solenoid header assembly that allow the operator to actually set and control the temperature of the pipe wall. The system then automatically injects the necessary amounts of LN2 required to freeze the pipe to the programmed temperature. The system can also be operated from remotely. Accu-Freeze is used by nuclear facilities and power plants across the USA and Europe and by the US Navy on nuclear submarines. Accu-Freeze was also used by NASA for an urgent hydraulic line repair on the Space Shuttle Atlantis while on the launch pad. Standard Accu-Freeze Kits are available for up to 12” diameter pipe (can be modified to accommodate larger pipe diameters) and can be used to freeze fluids with lower freeze points than water such as glycol.