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).
Two-handle faucets are most often found in the bathroom, but you see them in some kitchens. Two-handle faucets use three types of mechanisms. The first two are the same as two of the mechanisms used in a single-handle faucet: cartridge and ceramic disc. The third type is a compression (or reverse-compression) mechanism. Compression faucets are the simplest type, using rubber washers that get compressed against one another to seal the valve. They do tend to wear out faster than other faucet types, but are also least expensive to repair.
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