READY ACCESS That which enables a fixture, appliance or equipment to be directly reached without requiring the removal or movement of any panel, door or similar obstruction and without the use of a portable ladder, step stool or similar device.
REDUCED PRESSURE BACKFLOW PREVENTER A backflow prevention device consisting of two independently acting check valves, internally force loaded to a normally closed position and separated by an intermediate chamber (or zone) in which there is an automatic relief means of venting to the atmosphere, internally loaded to a normally open position between two lightly closing shutoff valves and with a means for testing for tightness of the checks and opening of the relief means.
RELIEF VENT A vent whose primary function is to provide circulation of air between drainage and vent systems.
RIM An unobstructed open edge of a fixture.
RISER/WATER PIPE RISER A water supply pipe that extends one full story or more to convey water to branches or to a group of fixtures.
RODENT PROOFING The installation of plumbing systems in a manner which will prevent the entry of rodents into a structure through openings created when any part of a plumbing system penetrates an exterior wall or floor assembly located near or on grade.
ROOF DRAIN A drain installed to receive water collecting on the surface of a roof and to discharge such water into a leader or a conductor.
ROUGH IN Parts of the plumbing system that are installed prior to the installation of fixtures. This includes drainage, water supply, vent piping and the necessary fixture supports and any fixtures that are built into the structure.