Governs where water pipes may run: branches kept within the dwelling they serve, no pipes cast into concrete, holes and notches in timber framing within set limits, grommets or sleeves in metal framing so pipe and frame do not touch, pipes in chases wrapped and ducts with removable covers, and pipes under slabs bedded in sand with cover below the slab, penetrations lagged, metal pipe lagged, no soft solder and few joints (2003 text). The 2021 edition changed the rules for water services in metal-framed walls to bring them into line with steel-framed housing industry practice (NASH); that text is not held.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.