Jointing rules by method: burrs removed, no heat damage, size changes made with fittings not crimping, threads to the relevant standard and sealed, bolted gland and Gibault joints below ground protected from corrosion, compression and roll-grooved joints to AS 3688 (roll-grooved below ground wrapped and outside buildings), flanges attached by the method suited to the material, silver brazing with compatible flux and not used on taps or valves above DN 20, plastics solvent cemented with primer, stainless steel above DN 25 butt welded by TIG or flanged, and (new in the 2021 list) plastics jointing expanded and dissimilar metals below ground isolated against galvanic corrosion (2003 text; the 2021 revision expanded plastics jointing).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.