Each device type has its own installation rules. Testable: registered break tanks and air gaps keep the Table 4.6.3.2 minimum vertical air gap (sized for the largest inlet where several feed one tank) and tanks meet Section 8; pressure type and spill resistant vacuum breakers sit at least 300 mm above the highest outlet, always vented and away from ponding (and freezing for the pressure type); double check valve and detector assemblies are kept from freezing; reduced pressure zone and detector devices have a permanently vented relief outlet at least 300 mm above finished surface, away from ponding and freezing; testable single check valves and detector assemblies are for fire services only, protected from freezing, accessible and isolated both sides. Non-testable: atmospheric vacuum breakers at least 150 mm above the highest outlet, with no downstream isolating valve, not pressurised over 12 hours, vented and full-bore; hose connection vacuum breakers downstream of the isolating valve, vented and not pressurised over 12 hours; dual check valves with atmospheric port or intermediate vent, and beverage dispenser dual checks, with vent ports at least 300 mm above surface and kept from ponding or freezing as specified; spring-loaded single checks (Australia) for fire services only, accessible, with an upstream isolating valve; pipe interrupters not on continuously pressurised systems and at least 300 mm above surface.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.