Page 37 - 2018_IRC

DEFINITIONS

[RB] ALTERATION. Any construction, retrofit or renova- [MP] BACKFLOW, WATER DISTRIBUTION. The flow
tion to an existing structure other than repair or addition that of water or other liquids into the potable water-supply piping
requires a permit. Also, a change in a building, electrical, gas, from any sources other than its intended source. Backsi-
mechanical or plumbing system that involves an extension, phonage is one type of backflow.
addition or change to the arrangement, type or purpose of the [MP] BACKPRESSURE. Pressure created by any means in
original installation that requires a permit. For the definition the water distribution system that by being in excess of the
applicable in Chapter 11, see Section N1101.6. pressure in the water supply mains causes a potential back-
[RB] ALTERNATING TREAD DEVICE. A device that flow condition.
has a series of steps between 50 and 70 degrees (0.87 and [MP] BACKPRESSURE, LOW HEAD. A pressure less
1.22 rad) from horizontal, usually attached to a center support than or equal to 4.33 psi (29.88 kPa) or the pressure exerted
rail in an alternating manner so that the user does not have by a 10-foot (3048 mm) column of water.
both feet on the same level at the same time.
[MP] BACKSIPHONAGE. The flowing back of used or
[RB] ANCHORED STONE OR MASONRY VENEER. contaminated water from piping into a potable water-supply
Stone or masonry veneer secured with approved mechanical pipe due to a negative pressure in such pipe.
fasteners to an approved backing.
[MP] BACKWATER VALVE. A device installed in a drain
[MP] ANCHORS. See “Supports.” or pipe to prevent backflow of sewage.
[MP] ANTISIPHON. A term applied to valves or mechani- [RB] BASEMENT. A story that is not a story above grade
cal devices that eliminate siphonage. plane. (see “Story above grade plane”).
[MP] APPLIANCE. A device or apparatus that is manufac- [RE] BASEMENT WALL. For the definition applicable in
tured and designed to utilize energy and for which this code Chapter 11, see Section N1101.6.
provides specific requirements.
[RB] BASIC WIND SPEED. Three-second gust speed at 33
[RB] APPROVED. Acceptable to the building official. feet (10 058 mm) above the ground in Exposure C (see Sec-
tion R301.2.1) as given in Figure R301.2(5)A.
[RB] APPROVED AGENCY. An established and recog-
nized agency that is regularly engaged in conducting tests, [MP] BATHROOM GROUP. A group of fixtures, includ-
furnishing inspection services or furnishing product certifica- ing or excluding a bidet, consisting of a water closet, lava-
tion, and has been approved by the building official. For the tory, and bathtub or shower. Such fixtures are located
definition applicable in Chapter 11, see Section N1101.6. together on the same floor level.
[MP] APPROVED SOURCE. An independent person, firm [RB] BATTERY SYSTEM, STATIONARY STORAGE.
or corporation, approved by the building official, who is com- A rechargeable energy storage system consisting of electro-
petent and experienced in the application of engineering prin- chemical storage batteries, battery chargers, controls and
ciples to materials, methods or systems analyses. associated electrical equipment designed to provide electrical
power to a building. The system is typically used to provide
[RB] ASPECT RATIO. The ratio of longest to shortest per- standby or emergency power, an uninterruptable power sup-
pendicular dimensions, or for wall sections, the ratio of ply, load shedding, load sharing or similar capabilities.
height to length.
[MP] BEND. A drainage fitting, designed to provide a
[RB] ATTIC. The unfinished space between the ceiling change in direction of a drain pipe of less than the angle spec-
assembly and the roof assembly. ified by the amount necessary to establish the desired slope of
[RB] ATTIC, HABITABLE. A finished or unfinished hab- the line (see “Elbow” and “Sweep”).
itable space within an attic. [MP] BOILER. A self-contained appliance from which hot

[RE] AUTOMATIC. For the definition applicable in Chap- water is circulated for heating purposes and then returned to
ter 11, see Section N1101.6. the boiler, and that operates at water pressures not exceeding
160 pounds per square inch gage (psig) (1102 kPa gauge) and
[MP] BACKFLOW, DRAINAGE. A reversal of flow in the at water temperatures not exceeding 250°F (121°C).
drainage system.
[RB] BOND BEAM. A horizontal grouted element within
[MP] BACKFLOW PREVENTER. A backflow prevention masonry in which reinforcement is embedded.
assembly, a backflow prevention device or other means or
method to prevent backflow into the potable water supply. [RB] BRACED WALL LINE. A straight line through the
building plan that represents the location of the lateral resis-
[MP] BACKFLOW PREVENTER, REDUCED-PRES- tance provided by the wall bracing.
SURE-ZONE TYPE. A backflow-prevention device con-
sisting of two independently acting check valves, internally [RB] BRACED WALL LINE, CONTINUOUSLY
force loaded to a normally closed position and separated by SHEATHED. A braced wall line with structural sheathing
an intermediate chamber (or zone) in which there is an auto- applied to all sheathable surfaces including the areas above
matic relief means of venting to atmosphere internally loaded and below openings.
to a normally open position between two tightly closing shut- [RB] BRACED WALL PANEL. A full-height section of
off valves and with means for testing for tightness of the wall constructed to resist in-plane shear loads through inter-
checks and opening of relief means. action of framing members, sheathing material and anchors.

12 2018 INTERNATIONAL RESIDENTIAL CODE ®
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