ABS (acrylonitrile-butadiene-styrene):

usually black plastic pipes used for drains, wastes and venting.



signifies access that requires the removal of an access panel or similar removable obstruction.


Air Admittance Valve:

a one-way valve designed to allow air into the plumbing drainage system when a negative pressure develops in the piping.


Air-Conditioning System:

a system that consists of heat exchangers, filters, supply, exhaust and return air systems, and shall include any apparatus installed in connection there within.


approved refers to approval by the building official as the result of investigation and tests conducted by him or her, or by reason of accepted principals or tests by nationally recognized organizations.


a term applied to valves or mechanical devices that eliminate siphonage.

the unfinished space between the ceiling joists of the top story and the roof rafters. 

Backflow preventer:
device that prevents the reverse flow of water, due to atmospheric or higher pressure, by means of a positive check valve.

Balloon frame:
a framing system in which studs and corner posts extend from the sill to the plate and the upper story floor joists are carried on ledgers or girts let into the studs.

vertical rods or spindles supporting a rail.

permanent joining of metallic parts to form an electrically conducive path to ensure electrical continuity and capacity to safely conduct and current likely to be imposed.

wood, steel, or other material used to stiffen a structure.

Branch Circuit:
the circuit conductors between the final breaker or fuse 
and the outlet or outlets it supplies.

Brick veneer:
brick used for outer surface of a framed wall.

metal or wood placed diagonally between joists to prevent joists from twisting.

Built-Up Roof Covering:
Two or more layers of felt cemented together and surfaced with a cap sheet, mineral aggregate, smooth coating or similar surfacing material.

Bus bar:
main power terminal to which circuits are attached through either fuses or circuit breakers. One bus bar serves the hot side; the other serves the neutral side.

Cap flashing:
that portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

window or door framing.

to fill a joint with mastic or asphalt cement to prevent leaks.

a primary vertical structure containing one or more flues, for the purpose of carrying gaseous products of combustion and air from a fuel burning appliance to the outside atmosphere.

Chimney cap:
protects chimney brick from weather. The chimney cap is generally made from concrete.

Chimney flashing:
sheet metal flashing that provides a tight joint between chimney and roof.

Chlorinated polyvinyl chloride (CPVC):
plastic pipe used with hot and cold water. This material is often used on the T&P drain line.

Circuit breaker:
device that interrupts electrical flow automatically in case of an overloaded circuit. The circuit breaker can be reset by either a switch or push button.

an accessible opening in the drainage system used for the removal of possible obstruction.

Closed cut valley:
method of roof valley treatment in which shingles from one side of the valley extend across the valley, while shingles from the other side are trimmed 2" from the valley center line. The valley flashing is not exposed.

any heating or cooling element made from pipe or tubing connected in series.

Collar tie:
tie or beam that prevents the roof from spreading; connects similar rafters on opposite sides of the roof.

Combustible Material:
any material not defined as noncombustible.

Conditioned Air:
Air treated to control temperature, relative humidity or quality.

receptacles and switches rated 20 amps or less and directly connected to aluminum conductors. Must be marked CO/ALR.

pump of a refrigerating mechanism that draws a vacuum or low pressure on the cooling side of the refrigerant cycle and compresses the gas into the high-pressure or condensing side of the cycle.

Cross Connection:
any connection between two otherwise separate piping systems whereby there may be a flow from one system to the other.

any exterior floor system supported on at least two opposing sides by an adjoining structure and/or posts, piers, or other independent supports.

conductors supplying panel boards other than service panels.

Flue Collar: 
the portion of a fuel burning appliance designed for the attachment of a draft hood, vent connector or venting system.

Flush Valve:
a device located at the bottom of a flush tank that is operated to flush water closets.

a vented heating appliance designed or arranged to discharge heated air into a conditioned space or through a duct or ducts.

the finished ground level adjoining the building at all exterior walls.

Grounding conductor:
A non-current-carrying conductor that provides an 
alternative path for equipment faults.

Ground Fault:
current returning to transformer on unintended path, such as equipment enclosures or ground wires.

Habitable Space:
space in a building for living, sleeping, eating, or cooking. Bathrooms bathroom closets, hall storage, or utility areas are not considered habitable space.

a structural member placed perpendicular to studs or joists that reinforces an opening, such as a window, and transfers loads to the adjacent framing member.

Heat Pump:
an appliance having heating or heating/cooling capability and that uses refrigerants to extract heat from air, liquid or other sources.

Hot Water:
water at a temperature greater than or equal to 120F (49C)

Ignition Source:
A flame, spark, or hot surface capable of igniting flammable vapors or fumes.

kitchen shall mean an area used, or designed to be used, for the preparation of food.

the electrical demand in watts or horsepower of a piece of electrical equipment.

Masonry Chimney:
a field-constructed chimney composed of solid masonry units, bricks, stones, or concrete.

Mechanical Draft System:
a venting system designed to remove flue or vent gasses by mechanical means, that consists of and induced draft portion under non-positive pressure or a forced draft portion under positive static pressure.

Natural Draft System:
a venting system designed to remove flue or vent gasses under nonpositive static vent pressure entirely by natural draft.

Noncombustible Material:
materials that pass the test procedure for defining non-combustibility of elementary materials as set forth in ASTM E 136.

a chamber that forms part of an air-circulation system other than the occupied space being conditioned.

Positive Roof Drainage:
the drainage condition in which consideration has been made for all loading deflections of the roof deck, and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation.

Pressure Relief Valve:
a pressure actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set. 

Return Air:
air removed from an approved conditioned space or location and recirculated or exhausted.

Roof Covering:
the covering applied to the roof deck for weather resistance, fire classification or appearance.

Roof Deck:
the flat or sloped surface not including its supporting members or vertical supports.

an opening in a wall or parapet that allows water to drain from a roof.

Service Entrance Conductors:
the conductors on the customer's premises the convey power to the service equipment.

Slip Joint:
a mechanical type joint used primarily on fixture traps. The joint tightness is obtained by tightening by compressing a friction type washer such as rubber, nylon, neoprene, lead or other special packing material against the pipe by the tightening of a (slip) nut.

Supply Air:
air delivered in a conditioned space through ducts or plenums from the heat exchanger of a heating, cooling or 
ventilation system. 

Temperature and Pressure Relief Valve (T&P):
A combination of a relief valve designed to function as both a temperature relief and pressure relief valve.

Temperature Relief Valve:
a temperature actuated valve designed to discharge automatically at the temperature at which it is set.

single-family dwelling unit constructed in groups of three or more attached units in which each unit extends from foundation to roof and with open space on at least two sides (IRC).

a fitting, either separate or built in to a fixture, that provides a liquid seal to prevent the emission of sewer gasses without materially affecting the flow of sewage or waste water through it.

one or more layers of felt, sheathing paper, non-bituminous saturated felt, or other approved material over which a roof covering, with a slope of 2/12 or greater is applied.

a passageway for conveying flue gasses from fuel fired appliances, or their vent connectors, to the outside atmosphere.

Vent Collar:
see flue collar

Vent Connector:
that portion of a venting system which connects the flue collar or draft hood of an appliance to a vent.

Vent Stack:
a vertical vent pipe installed to provide circulation of air to and from the drainage system and which extends through one or more stories.

Water Main:
a water supply pipe for public use.

Wet Vent:
a vent that also receives the discharge of wastes from other fixtures.