Free Journeyman Plumber Exam Flashcards

A vertical distance of 8 feet or more in developed length between the connections of horizontal branches to a drainage stack. It is a counting unit, not a story: a stack with five or more branch intervals requires a vent stack (IPC 904.2), so miscounting them is what puts a required vent stack on the wrong drawing.

Under the IPC, the building drain extends 30 inches in developed length beyond the exterior wall; past that point it is the building sewer. The UPC uses 2 feet instead. The boundary decides which sizing table, materials list, and inspection applies, so read the question for which code is referenced.

A VENT STACK is a vertical vent pipe installed only to circulate air to and from the drainage system - it carries no waste. A STACK VENT is the extension of a soil or waste stack above the highest horizontal drain connected to that stack. The names are nearly identical; the sizing rules and the required connections are not.

The FLOOD LEVEL RIM is the edge of the receptacle from which water overflows. The CRITICAL LEVEL (marked C-L) is the elevation reference on a backflow preventer below which backflow can occur, and it is what must be set above the flood level rim. Measure to the C-L mark - and where a device carries no C-L marking, the bottom of the device is treated as the critical level.

Fixture count and total drainage fixture units, the developed length from each trap weir to its vent connection, the height at which vents connect above the flood level rim, and the direction of flow through each fitting. A plan view flattens vertical runs, so the isometric is where venting and trap-arm violations become visible.

The length measured along the centerline of the pipe AND its fittings, not the straight-line distance between two points. Every vent limit, trap-arm limit, and hot-water length limit in the IPC is a developed length, so an elbow-heavy run fails long before a straight run of the same span would.

One inch on the paper equals 4 feet of building. A 3-inch measurement on the drawing is 12 feet of pipe. Check the title block for the scale before measuring - plumbing plans are commonly issued at 1/8 inch = 1 foot for large floor plates, which doubles every distance you scale off.

Fill the system so that no joint or pipe, except the uppermost 10 feet, is subjected to less than a 10-foot head of water. Hold 15 minutes with no drop; the system must then be tight at all points. The 10-foot exemption exists because the top of the system cannot be loaded without a standpipe above the roof.

Force air in to a uniform gauge pressure of 5 psi, or enough to balance a 10-inch column of mercury, and hold 15 minutes with no pressure loss. Two traps: 5 psi and 10 inches of mercury are the same test expressed two ways, not two different tests - and the section opens with 'Plastic piping shall not be tested using air,' so a PVC or ABS DWV system gets the water test.

Test at not less than the working pressure of the system; for piping systems OTHER THAN PLASTIC, an air test of not less than 50 psi is allowed instead. Hold 15 minutes. Same plastic exclusion as the DWV air test - you may not substitute an air test on a PEX or CPVC water system, only a water test at working pressure.

Fill every trap with water, introduce thick pungent smoke, close the stack openings when smoke shows at the roof, and hold a pressure equivalent to a 1-inch water column for at least 15 minutes. Note the scale change: the rough-in test is measured in feet of head, the final test in inches of water column.

Plug the shower drain watertight and fill the lined floor or receptor with potable water to a depth of not less than 2 inches measured at the threshold, building a temporary dam if no 2-inch threshold exists. Hold not less than 15 minutes with no evidence of leakage. This tests the liner, not the drain piping.

A weighted average lead content of not more than 0.25 percent across the wetted surfaces of pipe, fittings, valves, faucets and fixture fittings (NSF 372), and not more than 0.2 percent lead in solder and flux. The two limits are different numbers for different products - do not quote 0.25 percent for solder.

PVC is a water SERVICE pipe material only. It is not listed for interior water distribution at all - cold included, not just hot. CPVC is the plastic rated for interior hot and cold distribution. The common error is assuming PVC is banned only from hot lines.

A primer conforming to ASTM F656, which the code specifies as purple in color so an inspector can confirm from the outside that the pipe was primed. The purple is an inspection aid, not a performance property - an unprimed joint that looks clean is a rejected joint.

Pipe and tubing installed underground outside the structure must be rated not less than 160 psi at 73.4 degrees F. Hot water distribution pipe must be rated not less than 100 psi at 180 degrees F. Buried service pipe is rated for pressure at cold temperature; interior hot pipe is rated for pressure while hot.

PVC and ABS DWV: 4 feet horizontal, 10 feet vertical. Copper tubing 1-1/4 inch and smaller: 6 feet horizontal, 10 feet vertical. Cast iron: 5 feet horizontal, 15 feet vertical, increased to 10 feet horizontal where 10-foot lengths of pipe are installed. Plastic sags the fastest and gets the tightest spacing.

Not less than 6 inches below the frost line AND not less than 12 inches below grade. Both conditions apply, so in a no-frost region the 12-inch minimum still governs, and in a deep-frost region the frost line governs. Meeting only one of the two is the classic wrong answer.

Through a relieving arch or a pipe sleeve two pipe sizes larger than the pipe passing through it. The oversize gap lets the building settle without loading the pipe - a pipe grouted tight to the wall becomes a beam and shears.

After the DWV testing required by IPC 312.2 or 312.3 has been performed (IPC 918.2). An AAV is a one-way device and will not hold the water or air test, so installing it early either fails the test or tempts an untested system to be covered.

Not closer than 15 inches from the fixture centerline to any side wall, partition, vanity or obstruction; not closer than 30 inches center to center between adjacent fixtures; and not less than 21 inches clear in front to any wall, fixture or door. The 15-inch figure is a half-dimension, so two fixtures need 30 inches between centers, not 15.

Not less than 900 square inches of interior cross-sectional area and not less than 30 inches in least dimension, measured from the finished interior at the top of the threshold and carried up to 70 inches above the drain outlet. Exception: 25 inches least dimension is allowed if the compartment has at least 1,300 square inches. Valves, showerheads, soap dishes and grab bars are excluded from the measurement.

Not less than 22 inches of clear, unobstructed finished width. A compartment can satisfy the 900-square-inch area and 30-inch dimension rules and still fail because the door leaf or a fixed panel narrows the opening below 22 inches. Chapter 4 was resequenced alphabetically by fixture in the 2018 IPC, so the content is identical but the section number moved.

Must be balanced-pressure, thermostatic, or combination balanced-pressure/thermostatic valves conforming to ASSE 1016/ASME A112.1016/CSA B125.16 or ASME A112.18.1/CSA B125.1, installed at the point of use, with a means to limit the maximum setting to 120 degrees F, field adjusted per the manufacturer. A tank thermostat set to 120 does not satisfy this - the limit stop is on the valve.

Tempered water through a limiting device conforming to ASSE 1070/ASME A112.1070/CSA B125.70, capped at 110 degrees F (IPC 607.1.2). Two numbers, two devices: a public lavatory is limited to 110 degrees F by an ASSE 1070 device, while a shower or tub-shower valve is limited to 120 degrees F by an ASSE 1016 valve. The lavatory requirement sits at 416.5 in the 2015 IPC and moves with the Chapter 4 resequencing in 2018.

Showerhead: 2.5 gpm at 80 psi. Private lavatory faucet: 2.2 gpm at 60 psi. Public non-metering lavatory faucets: 0.5 gpm; metering faucets: 0.25 gallon per cycle. These values are IDENTICAL in the 2015 and 2018 IPC - the lower 2.0/1.5 gpm figures are EPA WaterSense or state amendments, not IPC base values.

Water closet: 1.6 gallons per flush. Urinal: 1.0 gallon per flush. Both values are the same in the 2015 and 2018 IPC. The 0.5 gpf urinal figure is an EPA WaterSense / state-amendment value, not an IPC base value - do not attribute it to an edition change.

Full size of the valve outlet or larger, discharging through an air gap in the same room, never connected to the drainage system, serving one relief device only, not trapped, flowing by gravity, terminating not more than 6 inches above the floor or receptor, with NO threaded end and NO valves or tee fittings. The threaded-end ban exists so nobody can cap a dripping line.

Where a leak would cause damage, the heater sits in a pan not less than 1-1/2 inches deep, drained by an INDIRECT waste pipe not less than 3/4 inch in diameter. The pan drain and the relief valve discharge line are separate items - the relief line may discharge into the pan, but the pan drain never substitutes for it.

Not less than 3/4 inch in diameter, regardless of how small the load calculation comes out. This is a floor, not a design result - a one-bathroom dwelling still gets a 3/4-inch service.

Not less than 5 feet of undisturbed or compacted earth. The widely quoted 10 feet is a water-utility and health-department rule, not the IPC. Alternatives: sleeve the water service to 5 feet horizontally on both sides of the sewer centerline, or keep the bottom of the water service not less than 12 inches above the top of the sewer using approved materials.

Where the static water pressure supplied to the building exceeds 80 psi. The PRV must conform to ASSE 1003, include a strainer, and reduce the pressure to 80 psi static or less. The trigger is STATIC pressure, so a system that reads fine while flowing can still require a PRV.

Lavatory 3/8 inch, water closet flush tank 3/8 inch, kitchen sink 1/2 inch, bathtub 1/2 inch, single-head shower 1/2 inch, hose bibb 1/2 inch, urinal flushometer valve 3/4 inch, and water closet FLUSHOMETER VALVE 1 inch. The flushometer valve water closet is the outlier at a full inch, because it draws the entire flush volume straight out of the supply pipe instead of refilling a tank between uses.

Critical level not less than 6 inches above the flood level rim of the fixture served, with NO shutoff or control valve downstream, and it may never be under continuous pressure - no more than 12 hours in any 24. A valve downstream traps pressure against the poppet and the device stops working.

An RPZ (ASSE 1013) protects against HIGH hazard - contamination, a health hazard - under continuous pressure, against both backpressure and backsiphonage. A DCVA is limited to LOW hazard, pollution only. Match the assembly to the hazard class in IPC Table 608.1; a DCVA on a health hazard is a code violation even if it is the newer device.

An atmospheric-type or pressure-type vacuum breaker, or a permanently attached hose connection vacuum breaker. 'Permanently attached' is the operative phrase - a screw-on brass breaker that a homeowner can remove does not satisfy the section unless it is designed and installed so it cannot be taken off.

2-1/2 inches or less: 1/4 inch per foot. 3 inches to 6 inches: 1/8 inch per foot. 8 inches or larger: 1/16 inch per foot. In the 2018 IPC (G25) only, 704.1 adds that drainage piping upstream of a grease interceptor must slope not less than 1/4 inch per foot regardless of size; the 2015 IPC (F25) has no such clause.

Bathroom group with a 1.6 gpf water closet: 5 dfu. Water closet, private, 1.6 gpf: 3 dfu; public: 4 dfu. Lavatory: 1 dfu. Bathtub, shower and kitchen sink: 2 dfu each. Note that the bathroom group value of 5 is LESS than summing its parts - the table already discounts for the fact that the fixtures are not used simultaneously.

At intervals of not more than 100 feet in horizontal drainage piping - ALL sizes, not just 4-inch and smaller - at each change of horizontal direction greater than 45 degrees, and at the base of each waste or soil stack. Clearance in front of the opening: not less than 18 inches for 6-inch and smaller pipe, not less than 36 inches for 8-inch and larger. The 18-inch/12-inch split some candidates memorize is the UPC rule, not the IPC.

Required where fixtures are installed on a floor whose FINISHED FLOOR ELEVATION is below the elevation of the manhole cover of the next upstream manhole in the public sewer. Fixtures on floors above that elevation shall not discharge through the backwater valve, so routing a whole building through one valve is a violation. Section number moved between editions: 715.1 in the 2015 IPC (F25), renumbered 714.1 in the 2018 IPC (G25).

Not less than 18 inches in diameter and not less than 24 inches in depth unless otherwise approved, fitted with a gas-tight removable cover installed flush with, or above, grade or floor level, and vented in accordance with Chapter 9. A sewage pit is a sealed, vented part of the DWV system - not an open sump like a clear-water groundwater pit.

A check valve first, then a FULL OPEN valve on the discharge side of the check valve, between the pump and the gravity drainage system, both located above the sump cover or in an accessible below-grade access pit. The order matters: the full open valve downstream lets you isolate the line and still service the check valve. The line is sized around the pump, which must pass spherical solids up to 2 inches where it receives water closet discharge, and 1 inch otherwise.

An AIR GAP is a physical open space between the indirect waste pipe and the flood level rim of the receptor, not less than twice the effective opening of the indirect waste pipe. An AIR BREAK only requires separation between the waste pipe and the TRAP SEAL, so the pipe may end below the flood level rim. Food-handling equipment and potable clear-water waste require an air gap; a commercial dishwashing machine may use either.

Not less than one-half the required diameter of the DRAIN SERVED, and never less than 1-1/4 inches. The drain served is the pipe continuing downstream of the vent connection, not the trap or the trap arm - so a 4-inch drain takes a 2-inch vent and a 3-inch drain takes a 1-1/2 inch vent. Vents exceeding 40 feet developed length increase one nominal size for the entire length.

1-1/4 inch trap: 5 feet. 1-1/2 inch: 6 feet. 2 inch: 8 feet. 3 inch: 12 feet. 4 inch: 16 feet. The 1-1/4, 1-1/2 and 2 inch rows are at 1/4 inch per foot slope; the 3 and 4 inch rows are at 1/8 inch per foot. Know which end you are measuring: this table runs from the TRAP WEIR TO THE VENT. The distance from the FIXTURE OUTLET TO THE TRAP WEIR is a separate Chapter 10 limit - 24 inches vertical, 30 inches horizontal. Both are developed lengths, so every elbow counts.

Never directly beneath any door, openable window, or other air intake of this or an adjacent building, and not within 10 feet horizontally of such an opening unless it is 3 feet or more above the top of the opening. Where the roof is used as a promenade, observation deck, sunbathing deck or for assembly, the vent terminates not less than 7 feet above the roof. The plain roof-extension height in 903.1 is a bracketed value each jurisdiction fills in, so confirm it locally.

Not less than 2 inches and not more than 4 inches, except where a deeper seal is required for special designs relating to accessible fixtures (evaporation risk is handled by trap-seal protection devices, not a deeper seal). Deeper is not safer: a seal over 4 inches holds solids and stops being self-scouring, while a seal under 2 inches is siphoned or blown out by ordinary system pressure swings.

1. Traps that depend on moving parts to maintain the seal. 2. Bell traps. 3. Crown-vented traps. 4. Traps not integral with a fixture that depend on interior partitions for the seal, except those of approved corrosion-resistant material. 5. 'S' traps. 6. Drum traps - excepted only where used as a solids interceptor or serving a chemical waste system. Separately, IPC 1002.6 states flatly that building (house) traps shall be prohibited, with no code-official exception.

In the 2018 IPC (G25), piping upstream of a grease interceptor must slope not less than 1/4 inch per foot, overriding the Table 704.1 slopes that would allow 1/8 inch per foot on 3-inch to 6-inch pipe. The 2015 IPC (F25) has no such requirement - Table 704.1 slopes govern all the way to the interceptor. Grease cools and sets on a flat run, so the 2018 code buys velocity with grade.

No. Storm water shall not be drained into sewers intended for sewage only. Where the public sewer is a combined system, the building storm drain is connected independently to the public sewer rather than tied into the sanitary building drain, and that storm connection is trapped so sewer gas cannot reach roof drains and area drains.