IRN R410


Every water closet pan shall be supplied with water from a flushing cistern, pressure flushing cistern or pressure flushing valve, and shall be so made and installed that after normal use its contents can be cleared effectively by a single flush of water, or where the installation is designed to receive flushes of different volumes, by the largest of those flushes.


No pressure flushing valve shall be installed -



in a house, or



 in any building not being a house where a minimum flow rate of 1.2 litres per second cannot be achieved at the appliance.


No flushing device installed for use with a WC pan shall give a single flush exceeding 6 litres.