See
link titlecondensation you buy Lagging, which is made of rigid foam and comes in tubular shape that is cut across the length. The slit allows you to 'lag' the pipe with the Lagging, thereby insulationg it from direct contact with opposing atmospheric changes like hot or cold air.">Lag Lagging means different things to different people, depending in what industry they work. Lagging a Pipe means to wrap a pipe that conducts hot or cold water or other substances or electricity. For example, to prevent link titlecondensation you buy Lagging, which is made of rigid foam and comes in tubular shape that is cut across the length. The slit allows you to 'lag' the pipe with the Lagging, thereby insulationg it from direct contact with opposing atmospheric changes like hot or cold air.