knowledge of boring holes in structural framing without comprising the integrity, a pvc dwv system can typically be installed by one individual experienced plumber as opposed to cast iron, which requires several people in order to install and remove. Most pvc dwv systems that replace cast iron systems require the complete removal of the cast iron in order to provide a proper functioning dwv system leaving only enough cast iron pipe (at the lowest point to the ground in which it tyes into the sewage) in order for a specialized rubber boot coupling, known as a fernco, to be installed in order to join the pvc system to waste drainage. A special fitting known as a test tee should immediately follow the installation of the fernco in order to adequately test the system to make sure no leaks are present and that adequate vent pressure is draining the waste water correctly. The means to properly test any dwv system is done with an inflatable apparatus known as a test ball which is placed in a test tee which should be located at the bottom most point of the system before going into the ground. See also Fuel gas piping Plumber Potable cold and hot water supply Rainwater, surface, and subsurface water drainage References Further reading Building engineering