Hot Tapping or pressure tapping, is a coring process on an existing piping or pressure vessel without interrupting or emptying of that section of pipe or vessel. This means that a pipe or tank can continue to be in operation whilst maintenance or modifications are being done to it.
Line Stopping or Line Plugging is a means of isolating a section of a piping system to provide a shut off to the flow of a particular section without interrupting the flow of the entire piping system. This process serves as a control, or temporary valve, that can be removed after permanent alterations or valve replacements or any additions have been made to the piping system.