Definitions & terms: South Dakota Journeyman Plumber Practice Questions

In the plumbing codes, what is an air gap in a water supply system?

An air gap is an unobstructed vertical opening through the atmosphere between the supply outlet and the flood level rim. Because the water must jump the gap, nothing can be siphoned back into the supply.

An indirect waste pipe ends below the flood level rim of a floor sink but above its trap seal, and the joint is open to the air. This connection is called:

An air break discharges into a receptor below its flood level rim but above the trap seal without a sealed joint. An air gap would end above the flood level rim.

What is backflow?

Backflow means contaminated or unwanted water entering the potable supply from anywhere other than its intended source. It happens by backpressure or backsiphonage.

A boiler feed line is connected to the potable water supply. If the boiler pressure rises above the supply pressure and pushes boiler water into the potable lines, this type of backflow is called:

Backpressure backflow happens when downstream pressure is higher than the supply pressure, as with a boiler, pump or elevated tank. Backsiphonage is caused by a vacuum in the supply instead.

A water main breaks and the pressure in the street drops below atmospheric. Dirty water in a sink is drawn back into a submerged faucet spout. This is:

Backsiphonage is backflow caused by negative or sub-atmospheric pressure in the supply piping. A main break or heavy fire-hydrant draw are typical causes.

Any physical connection or arrangement between a potable water system and a nonpotable system or substance is called a:

A cross connection is any link through which nonpotable water, liquids or gases could enter the potable system. The codes require each one to be eliminated or protected.

Water that is safe for drinking, cooking and personal use and meets health authority standards is called:

Potable water is free of impurities in amounts that could cause disease or harmful effects and meets the health authority's drinking water requirements.

Which of these discharges is NOT gray water under the plumbing codes?

Gray water comes from lavatories, bathtubs, showers, clothes washers and laundry trays. Kitchen sink and dishwasher waste carry food and grease, so they are excluded along with toilet waste.

What is the flood level rim of a fixture?

The flood level rim is the edge over which water spills when the fixture overfills. Air gaps, vacuum breaker heights and vent connection heights are measured from it.

The length of a pipe measured along its centerline, including the fittings, is called its:

Developed length follows the centerline of the pipe and fittings. Trap-arm, vent and gas pipe limits are based on it, not on straight-line distance.

A pipe that carries the discharge of water closets, urinals or other fixtures with fecal matter is a:

A soil pipe carries sewage that includes fecal matter. A waste pipe carries only liquid waste without fecal matter, such as from lavatories and sinks.

The general term for any vertical line of soil, waste or vent piping that extends through one or more stories is:

A stack is any vertical soil, waste or vent line running through one or more stories. Stack vents and vent stacks are kinds of vent piping related to it.

The extension of a soil or waste stack above the highest horizontal drain connected to it is the:

A stack vent is the same pipe as the drainage stack, continued upward above the highest branch. A vent stack is a separate vertical vent pipe that runs beside the drainage stack.

A vertical vent pipe installed mainly to provide air circulation to and from the drainage system, and running through one or more stories, is a:

A vent stack is its own vertical vent line, usually connected at the base of the drainage stack and back into the stack vent or through the roof.

What is the main job of a trap?

A trap is a fitting or device that holds water to seal out sewer gas while letting waste pass freely. It is not meant to catch solids.