Pipes are sized on the minimum pressure available from the supply (the water utility can give main pressures). The furthest or least favoured outlet must get at least 50 kPa working pressure at its Table 3.2.1 flow. The design must allow for the pressure lost in pipework, fittings, valves, meters and any equipment. Static pressure at any outlet inside a building, other than fire outlets, may not exceed 500 kPa. Where the supply cannot give the required pressure and flow, storage tanks, with or without pumps, are installed to achieve them.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.