Journeyman Plumber flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Authority having jurisdiction

The official or agency that enforces the adopted plumbing code and approves materials, methods, and inspections; local amendments take precedence over the model code text.

Trap seal depth requirement

A fixture trap must hold a liquid seal between 2 and 4 inches deep, measured from the trap weir to the top of the dip, to block sewer gas from entering the building.

Standard drainage slope

Horizontal drainage pipe 2-1/2 inches and smaller must slope at least 1/4 inch per foot, while 3-inch through 6-inch pipe may slope at 1/8 inch per foot.

Drainage fixture unit

A unit expressing the probable discharge rate of a fixture; one drainage fixture unit is about 1 cubic foot per minute, or roughly 7.5 gallons per minute.

Vent terminal above roof

A vent stack must extend at least 6 inches above the roof surface and may need to be enlarged to 2 inches in cold climates to resist frost closure.

Trap arm length limit

The developed length from the trap weir to the vent fitting is limited by pipe size, roughly 5 feet for 1-1/4 inch, 8 feet for 2 inch, and 16 feet for 4 inch pipe.

Minimum vent pipe size

No vent may be smaller than 1-1/4 inches nominal, and a vent must be at least one-half the diameter of the drain it serves.

Cleanout at base of stack

A cleanout is required at the base of every vertical soil or waste stack and at the upper end of each horizontal drainage pipe before it turns downward.

Pressure reducing valve threshold

A pressure-reducing valve is required when supply pressure exceeds 80 psi, and downstream static pressure is limited to 80 psi to protect fixtures and piping.

Water hammer arrestor

A device with a trapped air chamber or piston installed near a quick-closing valve to absorb the pressure surge created when water flow stops abruptly.

Backflow prevention device

A testable assembly or air gap that stops contaminated water from reversing into the potable supply; required at boilers, irrigation, and other cross-connections.

Thermal expansion tank

A closed potable water system with a check valve or backflow preventer needs an expansion tank to absorb the volume increase as water heats, preventing overpressure.

Water closet flush volume

New residential water closets are limited to 1.6 gallons per flush by federal standard, and many current models use only 1.28 gallons per flush.

Showerhead maximum flow

Showerheads are limited to 2.5 gallons per minute at 80 psi, while lavatory and kitchen faucets are commonly limited to 2.2 gallons per minute.

Water closet rough-in clearance

A water closet needs at least 15 inches from its centerline to any side wall or partition and at least 21 inches of clear space in front of the bowl.

Urinal flush volume

Urinals are limited to 1.0 gallon per flush; waterless urinals rely on a liquid seal cartridge and require special maintenance and drain line provisions.

T&P relief valve setting

A temperature and pressure relief valve on a storage water heater is typically rated 150 psi and 210 degrees F and is installed in the top 6 inches of the tank.

Relief valve discharge pipe

The discharge pipe must be full size, flow by gravity, have no valves or traps, and terminate within 6 inches of the floor or outside the building.

Water heater recovery rate

Recovery in gallons per hour equals input BTU per hour times efficiency divided by 8.33 times the temperature rise; a 40,000 BTU unit at 80 percent and 90 degrees rise gives about 42 gph.

Gas water heater in garage

A gas-fired water heater installed in a garage must have its ignition source elevated at least 18 inches above the floor to avoid igniting gasoline vapors.

Gas sediment trap

A drip leg or sediment trap is installed downstream of the appliance shutoff valve and as close as practicable to the appliance inlet to catch dirt and pipe dope.

Gas appliance shutoff valve

A manual shutoff valve must be installed in the same room as the appliance and within 6 feet of it, upstream of the sediment trap and connector.

Combustion air unconfined space

An unconfined space needs about 50 cubic feet of volume per 1,000 BTU per hour of input, or 1 square inch of free grille area per 1,000 BTU per hour.

CSST bonding requirement

Corrugated stainless steel tubing gas piping must be bonded to the grounding electrode system with a minimum 6 AWG copper conductor at the manifold or as listed.

Trench protective system threshold

A protective system such as sloping, shoring, or a trench box is required for any excavation 5 feet deep or greater, unless the material is solid rock.

Ladder four to one rule

A portable ladder is set with its base 1 foot out from the wall for every 4 feet of working height and extends 3 feet above the landing surface.

Call before you dig

The 811 notification service must be contacted before excavation so underground utilities can be located and marked, typically two to three working days ahead.

Flare fitting pipe dope

Pipe dope or thread sealant is never applied to the sealing surfaces of flare or compression fittings; it is used only on tapered pipe threads.

Reading drawing scale

At a scale of 1/4 inch equals 1 foot, one inch on the drawing represents 4 feet in the field, so measured drawing distance is multiplied by 4.

45 degree offset travel

For a 45-degree offset, travel equals offset times 1.414, and the offset equals travel times 0.707 when the diagonal run between fittings is known.

Static head to pressure

Each foot of water column elevation produces about 0.433 psi, so 1 psi equals 2.31 feet of head and 10 feet of rise adds about 4.33 psi.

Pipe volume to gallons

One gallon holds 231 cubic inches, so pipe volume per foot in gallons equals pi times the inside radius squared times 12, divided by 231.