DIN, BS, AWWA, AS products. Typically water transmission pipelines are either constructed using concrete pressure pipes, ductile iron pipes, steel pipes or GRP/GRE pipes. At the lower end of the dimensional range plastic pipes (such as HDPE) may be used.
There are various historical/design reasons as to why individual authorities & consulting engineers may prefer different valve designs. Some designers are more comfortable with gate valves others with butterfly valves – and within each valve category there are also more design options available. Choice of valves can also depend on project specific applications as well as availability for different pressure classes.