As a common method for air conditioning repair, pipe freeze plugging is a technique whereby a technician can isolate a section of water pipe for repair when a valve is not present to interrupt water flow to the damaged area. It also allows for repairs on multi-line systems by allowing the technician to isolate one section of pipe without the need to either interrupt water flow to the rest of the system or to purge it of fluid. The applications range from kits suitable for the layman or homeowner to systems designed for plumbing professionals working in settings ranging from residential and commercial plumbing to industrial pipe maintenance in factories, refineries and other processes that use large-scale water systems.
One can buy a basic one-or-two-use pipe freezing kit online or at many hardware or home-supply stores. These kits consist of a can of refrigerant ranging from carbon dioxide to nitrogen to R-134a (such as is used in modern automotive air conditioning systems), pipe jackets of various sizes to contain the refrigerants and the various valves, tubing and pieces of hardware that complete the setup. One simply attaches the refrigerant jacket to a section of the pipe before the break and applies the refrigerant according to the instructions. This reduces the temperature of the pipe and the water within to well below zero Celsius. After sufficient time the water will freeze solid and form a plug that will remain in place for as long as a half hour, allowing the technician enough time to repair the damaged section of pipe or install a valve.
Professionals that commonly encounter these repairs can get an all-in-one tool that simplifies the process and contains everything necessary to do the procedure repeatedly without the need to replace disposable parts or spent refrigerant. These kits contain the refrigerant in a closed-loop unit that is simple, cost-effective and environmentally friendly. The technician plugs in the unit, attaches the clamp or clamps to the pipes and turns it on. When the machine indicates that the plug has set, the worker proceeds with the repair. One machine can service several pipes in sequence allowing for multiple instances of pipe isolation within the time frame permitted by the thawing of the initial plugs.
Pipe freeze plugging is a simple, fast and easy solution to the messy and often dangerous problem of how to work on a water pipe while it is under pressure.