V Definitions

Definition Categories

Valley (closed-cut)

A closed-cut valley is a type of closed valley where roof covering material is installed through the valley on one side and where the roof covering material from the other side of the valley is cut along the valley center line.

Valley (closed)

A closed roof valley is one where the roof covering material is installed through the valley and up the opposite side of the valley.

Valley (open)

An open roof valley is one where the valley lining material is exposed and the roof covering material is cut away from the valley center line.

Valley (woven or laced)

A woven valley (also called a laced valley) is a type of closed valley where the roof covering material from one side of the valley is installed under the roof covering material from the other side of the valley giving the valley a woven appearance.

Vent

A vent is pipe or mechanical device that allows air into the plumbing drain pipes to equalize air pressure in the pipes. Plumbing vents help avoid draining (siphoning) traps and help waste water flow freely through the system. Plumbing vents usually terminate on the roof, although mechanical vents (called air admittance valves) are allowed in some circumstances.

Vent

A vent is a generally vertical component, such as a metal pipe, that conducts combustion products from a gas appliance to the outdoors. A vent for a single gas appliance begins at the fitting where the vent connector, if any, connects to the vent. A common vent for multiple gas appliances begins at the highest connector fitting. If a vent is located directly over the appliance draft hood or flue collar, or if the vent connects directly to the gas appliance (as in Category III and IV gas appliances), then the vent begins at the gas appliance and there is no vent connector.

Vent (dry)

A dry vent is a plumbing vent that is not intended for soil or waste water flow.

Vent connector

A vent connector is a pipe that connects a gas appliance to its vent or flue. A vent connector is required if the gas
appliance is not located directly under its vent. A vent connector for a Category I gas appliance may be a listed vent material, such as a Type B vent, or a listed flexible vent connector, or a field constructed single wall metal pipe made of at least 0.018 in. (approximately 28 gage) galvanized steel, or other approved material. While a vent connector is part of the venting system, it is not the vent itself. This IRC section contains provisions applicable to vent connectors for Category I gas appliances. Section G2428 contains provisions applicable to the vent itself.

Vent connector

A vent connector is a pipe that conducts the combustion products from a fuel burning appliance to a vertical vent or flue. A vent connector is required when the appliance draft hood or vent connection does not line up with the vent or flue. Vent connectors may be single wall metal pipe, or a factory-built chimney material, or a listed Type L double-wall pipe.

Vent diameter (D)

The vent diameter is the length in inches of the vent opening.

Vent height

Vent height is the total height of the vent and any vent connector measured from the draft hood or flue collar of the highest connected appliance on one building level or floor to the bottom of the listed vent cap or the end of the chimney flue.

Vent stack

A vent stack is a dry vent that connects at or near the connection of a soil or waste stack and a horizontal drain.  A vent stack runs vertically and often runs parallel to the soil or waste stack that it vents.

Voltage

Voltage is a measure of the potential difference between two conductors in a circuit. Voltage is similar to the water pressure in a pipe. In most residential electric systems, the nominal voltage potential between the two ungrounded (hot) wires is approximately 240 volts and the nominal voltage potential between an ungrounded (hot) wire and the grounded (neutral) wire is approximately 120 volts. The actual voltage in a circuit is usually diff erent from the nominal voltage. Voltage is measured in volts and is expressed in Ohm’s Law as the letter E.