IRN R020

Multiple inlet fittings installed in domestic premises and supplied from unbalanced supplies (e/g hot and cold supplies from separate sources) shall be installed in accordance with IRN R010 and with a double check valve or some other no less effective backflow prevention device fitted at the connection to the shower hose pipe.

 A single check valve or vacuum breaker may be fitted in place of the double check valve if single check valves are fitted at each inlet to the fitting.

 Alternatively the fitting shall be supplied in accordance with IRN R040 unless the shower head is constrained above the spill-over level of the bath, wash basin or shower tray.