2
3.1.4 Blowout bowl: a non-siphonic water closet bowl with an integral flushing rim,
a trap at the rear of the bowl, and a visible or concealed jet that operates with a
blowout action.
3.1.5 Critical level (CL): the highest water level of a supply fitting at which back
siphonage will not occur.
3.1.6 Dual flush: a feature that allows the user to flush the water closet with either a
reduced or full volume of water depending upon bowl contents.
3.1.7 Electro-hydraulic water closet: a water closet with a non-mechanical trap seal
incorporating an electric motor and controller to facilitate flushing.
3.1.8 Fill time: the time from the instant the flush valve of a flush tank closes until the
instant the fill valve is completely shut off.
3.1.9 Fitting: a device that controls and guides the flow of water.
3.1.10 Fixture: a device that receives water, waste matter, or both and directs these
substances into a drainage.
3.1.11 Flood level: the level at which water will overflow a fixture.
3.1.12 Flush cycle: the complete operating sequence of a water closet in emptying its
contents, cleaning its inside surfaces, and refilling the water seal.
3.1.13 Flushing device: a device for delivering water into a water closet bowl.
3.1.14 Flush valve: a valve for discharging water from a flush tank into a water closet
bowl.
3.1.15 Flushometer tank: a flushing device that effectively enlarges the water supply
pipe immediately before the water closet bowl by being integrated within an
accumulator vessel affixed and adjacent to the fixture inlet.
3.1.16 Flushometer valve: a flushing device attached to a pressurized water supply
pipe that, when actuated, opens the pipe for direct flow into the fixture at a rate
and in a quantity that enables proper operation of the fixture. The valve then
gradually closes to provide trap reseal in the fixture and avoid water hammer.
Note: The pipe to which the flushometer valve is connected should be large enough to
enable delivery of water at a sufficient rate for proper operation.
3.1.17 Flushing surface: a surface that is visible after installation and is wetted during
operation of a water closet.
3.1.18 Gravity water closet: a vessel that stores a predetermined quantity of water and
includes a flushing device to discharge water (plus some through-flow from the
water supply line) into a water closet bowl.
Note: A common type of gravity water closet is a wall-hung vessel or a vessel close-
coupled with the water closet bowl that is fitted with a fill valve and flush valve.
3.1.19 Gravity flush tank water closet: a water closet designed to flush the bowl with
water supplied by gravity only.
3.1.20 Integral: a cast or formed part of a fixture, e.g., a trap, seat, or flush tank.
