Pipe freezing is a method used to freeze the contents of a section of pipes by applying a cryogenic freezing agent in a controlled manner. When the ice plugs are formed maturely, maintenance works to the pipe can be carried out between the ice plugs without draining massive amount of pipe fluid. This is used for maintenance and repair works on pipelines with non-functional valves. It is also used for replacing valves or flanges in pipelines with no zone valves. It works on Insertion of branch in pipelines with no zone valves.