Red Seal Plumber flashcards
Red Seal Plumber · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Fixture unit (FU)
- A unit expressing the probable demand of a fixture on the water supply; about 1 FU equals 1 gpm, and fixture units are summed to size supply piping.
- Developed length
- The total pipe length along the longest run from the water source to the farthest fixture, including an allowance for fittings and valves; used to size supply pipe.
- Trap arm length limit
- The distance from a fixture trap to its vent; it is limited by pipe size, for example about 5 ft for 1-1/4 in and 8 ft for 2 in pipe.
- Hydrostatic water test
- A pressure test of the water distribution system, typically at 100 psi for 60 minutes with no pressure drop, performed before the piping is concealed.
- Drainage air test
- A test of the DWV system using air at about 5 psi for 15 minutes, an alternative to the water test used when water is impractical.
- Air gap backflow protection
- The unobstructed vertical distance between a supply outlet and the flood-level rim of a receiving vessel; it provides the highest level of cross-connection protection.
- T&P relief valve
- A temperature and pressure relief valve on a water heater that opens at a set limit; its discharge must terminate safely, usually within 6 in of the floor.
- Thermal expansion tank
- A tank installed on a closed water system to absorb the volume increase caused by heating, preventing excessive pressure and relief valve discharge.
- Combustion air openings
- Two permanent openings, one high and one low, that supply air to a confined space containing a fuel-burning appliance; each is sized by the appliance input.
- Drain cable sizing
- Matching a drain cleaning cable to pipe diameter: 5/16 in for 1-1/4 to 2 in lines, 3/8 in for 2 to 3 in, and 1/2 in for 3 to 4 in.
- Stack vent
- The continuation of a soil or waste stack above the highest fixture connection, which vents the stack to the outdoors above the roof.
- Water closet spacing
- Minimum clearances for a water closet: at least 15 in from centerline to a side wall and 30 in between adjacent fixture centerlines.
- Lead-free definition
- A material containing not more than 0.25 percent weighted average lead in its wetted surfaces, required for potable water pipe, solder, and flux.
- Building drain
- The lowest horizontal piping of a drainage system, which receives soil and waste from the stacks and conveys it to the building sewer.
- Drainage fixture unit
- A unit expressing the probable flow a fixture adds to the drainage system; a water closet is 4 DFU private and a lavatory is 1 DFU.
- Trap seal depth
- The vertical depth of water retained in a fixture trap, normally 2 to 4 in, which blocks sewer gas from entering the building.
- Cleanout location
- A fitting giving access to a drain for clearing blockages, required at the base of each stack, at the building sewer, and at intervals along long horizontal runs.
- Water hammer arrestor
- A device installed near a quick-closing valve to absorb the pressure surge caused by sudden flow stoppage, preventing noise and pipe damage.
- Total dynamic head
- The sum of static lift, friction loss, and required discharge pressure that a pump must overcome; it is used to select a pump from its curve.
- Pressure-reducing valve
- A valve that lowers incoming water pressure to a set downstream value, commonly 50 to 60 psi, protecting fixtures and piping from excessive pressure.
- Dielectric union
- A fitting installed between dissimilar metals, such as copper and steel, to break electrical contact and prevent galvanic corrosion at the joint.
- PEX expansion fitting
- A connection method in which the pipe end is expanded and a fitting inserted; the pipe shrinks back to create a seal, rated for potable water.
- RPZ assembly
- A reduced-pressure zone backflow preventer used for high-hazard connections; it has two check valves and a relief valve and is tested annually.
- Disinfection of water lines
- Treating new or repaired potable water piping with a chlorine solution and then flushing it before use to kill bacteria introduced during work.
- Legionella control
- Managing hot water systems by keeping storage at about 140°F, circulating the water, and avoiding dead legs and stagnant piping.
- Water closet rough-in
- The distance from the finished wall to the center of the closet flange, commonly 12 in for a standard toilet; it must match the fixture before the flange is set.
- Vent height above fixture
- A vent must rise at least 6 in above the flood-level rim of the highest served fixture before it offsets horizontally.
- Water service sizing
- Selecting the service pipe from the total fixture-unit demand and the available pressure so the farthest fixture still receives adequate flowing pressure.
- Recirculation loop
- A hot water return loop that keeps hot water near fixtures, reducing wait time, but it increases energy use and must be insulated and controlled.
- Tankless sizing
- Selecting a tankless water heater by the peak flow rate and the temperature rise required, since it heats water instantly and cannot store a reserve.
- Backwater valve
- A valve on the building sewer that closes to prevent sewage from the public main from backing up into the building; it must be accessible for maintenance.
- Septic tank sizing
- Determining tank volume from the number of bedrooms or daily flow, commonly about 1,000 to 1,500 gallons for a single-family dwelling.