Definition of TermsAir GapAn air gap in a water supply system, is the unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixtures or other device and the flood level rim of the receptacleBack SiphonageRefers to the back flow of used contaminated or polluted water from a plumbing fixture or vessel into a water supply pipe due to a negative pressure in such a pipeBattery of FixtureRefers to any group of two or more similar adjacent fixtures which discharges into a common horizontal waste pipe or soil branchBibSynonymous with faucet, cock, tap, plug, etc. The word faucet is preferred.BranchAny part of piping system other than the main riser or stackCombination FixturesFixture combining one sink and tray or a two or three compartment sink or tray in the ventCommon VentDrain from two or three fixture connected to a single trap. It is also called a dual vent.Cross ConnectionAny physical connection between two otherwise separate piping systems, one contains potable water, and the other from unknown or questionable safety, whereby, water may flow from one system to the other direction of flow depending on the pressure differential between the two systems.DiameterDiameter of a pipe or tube refers to the nominal internal diameter (ID) of such pipe, except brass and copper tube where the term refers to the outside diameter (OD) of the pipe.Drainage SystemDrainage system includes, all piping within the public or private premises that conveys sewage, rainwater, or other liquid waste, to a legal point of disposal. It does not include the mains of the public sewer system private or public sewerage treatment or disposal plant.Fixture BranchA pipe connecting several fixturesFixture SupplyA water supply pipe connecting the fixture with the fixture branchFlood LevelA device located inside the tank for the purpose of maintaining water level for effective flushing of the water closet.Ferrule a metallic sleeve called or otherwise joined to an opening in pipe into w/c a plug is screwed that can be removed for the purpose of cleaning or examining the interior of the pipe.Horizontal pipe.Means any type or fitting w/c makes an angle of more than 45 deg. With the vertical.Liquid wasteIs the discharge from any fixture, appliance or appurtenance in connection with a plumbing system w/c does not receive fecal matter.Plumbing fixturesare installed receptacle, devices or appliances w/c are supplied with water, or w/c receives or discharges liquid or liquid borne waste, with or w/out discharge into drainage system w/c maybe directly or indirectly connected.Plumbing systemthe plumbing system includes the water supply distribution pipes; plumbing fixtures and traps; soil, waste and vent pipes; house drain and house sewers including their respective connections, devices and appurtenances within the property lines of premises; and the water treating or waste using equipment.Riseris a water supply pipe w/c extend vertically one full storey or more to convey water to branches or fixtures.Pubic seweris a common sewer directly controlled by public authorities where all abutters have equal rights of connection.Soil pipeis any pipe that conveys the discharge of water closets or fixture having similar functions, with or without the discharge from other fixtures, to the building drains (house drain) or building sewer (house sewer)Stackis the vertical main of the system of soil, waste or vent pipe.Stack venta stack vent is the extension of a soil or waste stack above the highest horizontal drain connected to the stack. It is sometimes called the waste vent or soil vent.Trapis a fitting or device o designed as to provide when properly vented a liquid seal that will prevent the back passage of air without materially affecting the flow of sewage through it.Trap sealis the maximum vertical depth of liquid that trap will retain, measured between the crown weir and top of the dip of the trap.Vent systemis a pipe or pipes installed to provide a flow or circulation of air within the plumbing system to protect trap seals siphoning and back pressure.Vertical pipeis a pipe installed in a vertical positon or at an angle of not more than 45 degrees with the vertical.Waste pipeis a pipe that conveys liquid waste from fixture that is free of fecal matter.