DE Plumber flashcards

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

Drainage fixture unit

A unit expressing the probable discharge rate of a fixture into the drainage system, roughly equal to 1 cubic foot per minute of flow.

Trap seal depth

The vertical distance between the trap weir and the top of the trap dip, typically 2 to 4 inches, preventing sewer gas from entering the building.

Developed length

The total pipe length of a run including straight pipe plus equivalent lengths added for fittings, used when sizing water and gas piping.

Air gap

The unobstructed vertical distance between a supply outlet and the flood-level rim of a fixture, at least twice the outlet diameter and never less than 1 inch.

Pressure per foot of head

One foot of water column equals 0.433 psi, so 2.31 feet of elevation creates 1 psi of static pressure change.

Trap arm length limit

The maximum horizontal distance from a trap to its vent, which varies with pipe size, such as 5 feet for 1-1/4 inch pipe.

Water hammer arrestor

A device containing a trapped air chamber or piston that absorbs the pressure surge created when a valve closes quickly in a piping system.

Velocity in water supply

Water supply pipe is sized to keep flow velocity below about 8 feet per second cold and 5 feet per second hot to limit noise and erosion.

Model plumbing code adoption

The Uniform Plumbing Code or International Plumbing Code applies only as adopted and amended by the local jurisdiction, so the local edition governs.

Rough-in inspection

An inspection performed after piping is installed but before it is concealed, verifying pipe size, slope, support, and venting before covering.

DWV water test

A test of the drain, waste, and vent system, commonly holding a 10-foot head of water for 15 minutes without leakage.

Vent stack termination

Vent stacks must extend at least 6 inches above the roof and be located relative to windows and air intakes to prevent gas entry.

Cleanout placement

Cleanouts are required at the base of stacks, at direction changes over 135 degrees, and at intervals not exceeding 100 feet in horizontal drains.

Gas piping test pressure

Gas piping systems operating above 14 inches water column are commonly pressure tested at 10 psi for 30 minutes without leakage.

Permit requirement

New work, alterations, and replacements such as water heaters and sewers require permits, while ordinary repairs may be exempt by code.

Licensing versus code compliance

Licensing governs who may legally perform or contract plumbing work; code compliance governs how the work must be installed and inspected.

Backflow prevention device

An assembly such as a reduced pressure zone device or double check valve that prevents reverse flow of contaminated water into the potable supply.

Confined space oxygen level

An atmosphere with less than 19.5 percent oxygen is oxygen deficient and requires testing, ventilation, and entry procedures before worker entry.

Hydrogen sulfide hazard

Sewer gas is heavier than air and deadens the sense of smell at higher concentrations, so odor is not a reliable warning of exposure.

Trench protective systems

Excavations 5 feet or deeper require sloping, shoring, or shielding unless in stable rock, with inspection by a competent person.

Ladder setup angle

A ladder is set at roughly a 4:1 ratio, one foot out from the wall for every four feet of working height, with three points of contact.

Oxygen use prohibition

Oxygen must never be used as a substitute for compressed air to test piping or blow lines because it creates an extreme fire and explosion hazard.

Lead and asbestos awareness

Older solder, pipe, insulation, and cement products may contain lead or asbestos, requiring testing and regulated handling before disturbance.

Lockout/tagout

An energy isolation procedure in which equipment is de-energized, locked, tagged, and verified before service work begins.

Sewer gas protection

Workers protect against sewer gas and biological hazards using ventilation, PPE, and disinfection when repairing drains and sewer lines.

Bid price formula

Price equals cost divided by one minus the desired margin, where cost includes labor, material, equipment, overhead, and contingency.

Labor hour estimate

Estimated labor hours equal the quantity of work divided by the production rate, using historical rates per fixture or per foot of pipe.

Change order documentation

A written agreement describing scope, price, and schedule impact of extra work, signed before work proceeds to preserve the right to payment.

Retainage

A percentage of each payment, typically 5 to 10 percent, withheld by the owner until substantial completion to ensure project completion.

Critical path

The longest chain of dependent scheduled tasks; any delay on the critical path delays the project completion date.

Mechanic's lien rights

Statutory rights to file a claim against property for unpaid work, preserved by serving preliminary notices and filing within required deadlines.

Job cost variance

The difference between estimated and actual labor or material cost for a phase, used to correct current work and improve future bids.