Pipe freezing is a safe and effective way to temporarily plug a pipe. The technique involves installing a freezing machine that uses liquid nitrogen to locally freeze the substance in the pipe. The pipe contracts and the resultant plug takes the shape of a diabolo, which can withstand up to twice the normal operational pressure in the pipe.
Substances that can be plugged using this method include tap water, distilled water, waste water, closed circuit water, liquid sludge and flammable liquids. The maximum pipe diameter for localised freezing is 12" (DN 300) without flow.
Pipe freezing is a safe and effective way to temporarily plug a pipe using freezing technology.