Making Connections to Mild Steel Pipes
As is the case with lead pipes, mild steel pipes should be replaced wherever possible because their expected lifespan will by now have been well exceeded. They are probably badly corroded on the inside and this will have a substantial affect on the expected flow volume. Also, connections to mild steel pipework with copper will have the effect of creating additional problems through electrolytic corrosion, and any such connection could well become another separate blockage problem within a the space of a few years.
Bearing this in mind, if such a connection cannot be avoided, or is desired on a temporary basis until the mild steel pipes can be replaced, use the steps below to make it.
Both lead and mild steel pipes can be joined using appropriate compression joints, which employ a rubber compression ring. A threaded joint would, however, be preferable, either an external thread which consists of a male iron thread or an internal thread which consists of a female iron thread.
The threaded connection is achieved by first applying polytetrafluoroethylene (PTFE) jointing tape for a few turns onto the male thread of one of the pipes in clockwise direction. This is then wound into the female thread of the associated fitting to form the sound bonded joint.
The copper or plastic pipe is made as a compression connection onto this joint. Jointing paste can be used rather than PTFE tape, but care must be taken to confirm that it is acceptable to use it with the pipe’s contents, as indicated on the tin.