Cast iron and ductile iron pipe was long a lower-cost alternative to copper, before the advent of durable plastic materials but special non-conductive fittings must be used where transitions are to be made to other metallic pipes, except for terminal fittings, in order to avoid corrosion owing to electrochemical reactions between dissimilar metals (see galvanic cell).
I called BL Plumbing when a small leak started coming out of my shower. They responded quickly and Billy arrived in the afternoon. He diagnosed the problem and proposed a solution including cost. I approved and he went straight to work. Within the hour, the problem was resolved. Billy recommended work that was needed to reduce water pressure for the entire house. I approved the work including cost and Billy had that problem fixed quickly and efficiently. A small leak in the pipe below the shower led to a much needed home improvement. As we finished, Billy and I discussed potential future work and issues regarding maintenance concerning the overall projects completed that day. The entire process was a very positive experience.
PBT – flexible (usually gray or black) plastic pipe which is attached to barbed fittings and secured in place with a copper crimp ring. The primary manufacturer of PBT tubing and fittings was driven into bankruptcy by a class-action lawsuit over failures of this system. However, PB and PBT tubing has since returned to the market and codes, typically first for "exposed locations" such as risers.
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license