Line stop is the process of isolating a piping system to provide a shut off. This process serves as a control, or temporary valve, which can be removed after alterations or valve replacements have been made. With a hot tap previously made on a line, a line stopper is then attached to a temporary valve, and the valve is opened. The line stopper is hydraulically or mechanically pushed into the line to seal the pipe. After performing the necessary service, the stop is removed, and a blind flange is installed onto the sleeve.