Journeyman Plumber (UPC/IPC) — All Questions

Static pressure at the water meter reads 68 psi. The highest fixture served is 32 ft above the meter. Ignoring meter and friction losses, how much pressure remains at the elevation of that fixture?

• a.About 58.4 psi
• b.About 60.2 psi
• c.About 46.2 psi
• d.About 54.1 psi✓

Elevation loss is 0.433 psi for every foot of rise, so 32 ft x 0.433 = 13.86 psi, and 68 - 13.86 = 54.1 psi. The 60.2 and 58.4 answers come from using a smaller loss factor such as 0.25 or 0.3 psi per foot. The 46.2 answer wrongly applies 2.31 psi per foot, which is the inverse relationship (2.31 ft of head per psi).

How many feet of vertical head are equivalent to 22 psi of water pressure?

• a.About 9.5 ft
• b.About 22 ft
• c.About 50.8 ft✓
• d.About 45.4 ft

One psi equals 2.31 ft of head, so 22 x 2.31 = 50.8 ft. The 9.5 ft answer divides by 2.31 instead of multiplying, and 45.4 ft comes from using a rounded factor of 2.0 plus arithmetic error. Answering 22 ft ignores the conversion entirely and treats psi and feet as interchangeable.

A potable water supply outlet discharges over a receptor and the effective opening of the outlet is 1 in. What is the minimum required air gap?

• a.1-1/2 in
• b.2 in✓
• c.3 in
• d.1 in

The air gap must be at least twice the diameter of the effective opening, so 2 x 1 in = 2 in. The 1 in answer is only the code minimum floor that applies to very small openings, not the calculated value here. The 1-1/2 in choice uses a 1.5 multiplier and 3 in uses a 3x multiplier, neither of which the code uses.UPC §603.3.1

A supply outlet has an effective opening of 3/8 in. What minimum air gap must be provided above the flood level rim of the receiving vessel?

• a.2 in
• b.3/4 in
• c.1 in✓
• d.1-1/4 in

Twice the effective opening is 2 x 0.375 = 0.75 in, but the code sets an absolute minimum air gap of 1 in, so 1 in governs. The 3/4 in answer applies the 2x rule without checking the minimum. The 1-1/4 in and 2 in values are larger than anything the rule produces for a 3/8 in opening.IPC §608.15.1

A gauge on the building side of the meter shows a static street pressure of 96 psi with no flow. What does the plumbing code require?

• a.An approved vacuum relief valve installed on the water service ahead of the water meter assembly
• b.Nothing, because the pressure is still under 100 psi
• c.An approved pressure-reducing valve limiting downstream pressure to not more than 80 psi✓
• d.An increase of one pipe size on the water service

Where static pressure exceeds 80 psi, an approved pressure-reducing valve must be installed to hold the downstream distribution system at 80 psi or less. The 100 psi threshold does not exist in the code; 80 psi is the trigger. Upsizing pipe lowers friction loss but does nothing to static pressure, and a vacuum relief valve protects against collapse or siphoning, not high pressure.UPC §608.2

A 40 ft horizontal run of 3/4 in copper water tube is installed in a ceiling. Using a maximum horizontal support spacing of 6 ft for copper 1-1/2 in and smaller, what is the minimum number of hangers required?

• a.7 hangers✓
• b.5 hangers
• c.8 hangers
• d.6 hangers

40 ft divided by 6 ft equals 6.67 spaces, and since a partial space still needs a hanger you round up to 7. Answering 6 truncates the fraction and leaves a span longer than 6 ft. The 5 hanger answer assumes 8 ft spacing, and 8 hangers assumes the 5 ft spacing used for cast iron, not copper.UPC §313.3

A 24 ft horizontal run of 1/2 in CPVC water distribution pipe is supported at the maximum spacing of 3 ft. What is the minimum number of supports required?

• a.8 supports✓
• b.12 supports
• c.6 supports
• d.9 supports

24 ft divided by 3 ft equals 8 supports at the maximum allowed spacing. The 6 support answer uses the 4 ft spacing allowed for larger plastic pipe, and 12 supports assumes 2 ft spacing, which is more than the code requires. The 9 answer adds an extra support that the calculation does not produce.IPC Table 308.5

PEX tubing runs horizontally for 16 ft above a suspended ceiling. Using the maximum horizontal support spacing of 32 in for PEX, what is the minimum number of supports?

• a.6 supports✓
• b.3 supports
• c.5 supports
• d.4 supports

Convert first: 16 ft equals 192 in, and 192 divided by 32 equals 6 supports. The 4 and 3 answers come from using 48 in or 72 in spacing, which apply to rigid materials, not flexible PEX. Five supports would leave one span longer than 32 in and would allow the tubing to sag.IPC Table 308.5

To limit erosion-corrosion and noise, what is the generally accepted maximum design velocity in a copper hot water distribution line?

• a.8 feet per second
• b.10 feet per second
• c.12 feet per second
• d.5 feet per second✓

Hot water accelerates erosion of the copper tube wall, so hot lines are held to about 5 fps while cold lines are commonly designed to about 8 fps. The 8 fps answer is the cold water limit and is too aggressive for hot water. The 10 and 12 fps values are well above accepted design practice for any copper water line and would produce velocity noise and premature pinhole failures.

A commercial kitchen is being piped with solenoid-operated quick-closing valves on the dishwasher and ice machine supplies. What does the code require on those branches?

• a.A vacuum breaker on each supply branch
• b.A check valve installed immediately upstream of each quick-closing solenoid valve on the branch
• c.Approved water hammer arrestors sized and located per the manufacturer's instructions✓
• d.A larger supply pipe to slow the water velocity

Quick-closing valves stop flow almost instantly and convert momentum into a pressure spike, so the code requires approved water hammer arrestors on those branches. Upsizing pipe reduces velocity somewhat but does not satisfy the arrestor requirement. A check valve does not absorb the shock wave, and a vacuum breaker addresses back-siphonage, which is a different problem entirely.IPC §604.9

A potable water line supplies makeup water to a chemically treated boiler system and the connection is under continuous pressure. Which backflow prevention device is required?

• a.Hose bibb vacuum breaker
• b.Atmospheric vacuum breaker
• c.Double check valve assembly listed for continuous-pressure low-hazard service only
• d.Reduced pressure principle backflow preventer✓

Treated boiler water is a high hazard (health hazard) contaminant and the connection is under continuous pressure, which calls for a reduced pressure principle assembly. A double check assembly is only acceptable for low hazard, non-health, continuous pressure applications. An atmospheric vacuum breaker cannot be used under continuous pressure at all, and a hose bibb vacuum breaker is for hose outlets and protects only against back-siphonage.IPC §608.13

A fire sprinkler system with no antifreeze or chemical additives is connected to the potable water supply under continuous pressure. Which assembly is the appropriate minimum protection for this low hazard connection?

• a.Double check valve assembly✓
• b.Reduced pressure principle assembly
• c.Atmospheric vacuum breaker
• d.Pressure vacuum breaker

A non-additive sprinkler system is a low hazard (pollutant, not contaminant) connection under continuous pressure, which is the exact application for a double check valve assembly. A reduced pressure assembly exceeds the minimum required here and adds an unnecessary relief discharge. An atmospheric vacuum breaker may never be used under continuous pressure, and a pressure vacuum breaker protects against back-siphonage only, not back-pressure.IPC §608.13

An atmospheric vacuum breaker serves a fixture whose flood level rim is 34 in above the finished floor. What is the minimum height above the floor at which the vacuum breaker may be installed?

• a.40 in✓
• b.34 in
• c.46 in
• d.37 in

An atmospheric vacuum breaker must be at least 6 in above the flood level rim, so 34 + 6 = 40 in above the floor. Installing it at 34 in puts it level with the rim with no clearance at all. The 37 in answer uses a 3 in clearance and 46 in uses the 12 in clearance required for a pressure vacuum breaker above its highest outlet.IPC §608.13

A pressure vacuum breaker protects a lawn irrigation zone whose highest sprinkler head is 42 in above grade. What is the minimum height above grade for the vacuum breaker?

• a.4 ft 6 in✓
• b.3 ft 6 in
• c.4 ft 0 in
• d.5 ft 6 in

A pressure vacuum breaker must be at least 12 in above the highest downstream outlet, so 42 in + 12 in = 54 in, or 4 ft 6 in. The 3 ft 6 in answer is simply the head height with no clearance added. The 4 ft 0 in answer adds only 6 in, which is the atmospheric vacuum breaker rule, and 5 ft 6 in adds 24 in, more than the code requires.IPC §608.13

Which condition makes a pressure vacuum breaker an unacceptable choice for a given cross-connection?

• a.A booster pump downstream could push water back toward the supply✓
• b.The supply piping downstream of the device is copper tubing rather than galvanized steel
• c.The device would be located outdoors
• d.The outlet is a hose thread connection

A pressure vacuum breaker protects only against back-siphonage; a downstream pump creates back-pressure, which requires a double check assembly or reduced pressure assembly depending on the hazard level. Hose thread outlets, outdoor locations, and copper supply piping do not disqualify a pressure vacuum breaker. The distinction to remember is back-siphonage (negative supply pressure) versus back-pressure (higher downstream pressure).

Which copper tube designation has the heaviest wall thickness and is the type commonly required for an underground water service?

• a.Type L
• b.Type M
• c.Type DWV
• d.Type K✓

Wall thickness runs K heaviest, then L, then M, so Type K is specified where the tube is buried and exposed to soil and backfill loading. Type L is the common choice for interior water distribution and Type M is the thinnest pressure type, often restricted to above-ground use. Type DWV is not a pressure-rated water tube at all and is limited to drain, waste, and vent service.UPC §604.0

What is the maximum lead content permitted in solder and flux used on a potable water piping system?

• a.0.25 percent
• b.2 percent
• c.0.2 percent✓
• d.8 percent

Solder and flux used in potable water piping may not exceed 0.2 percent lead, which is why 50/50 tin-lead solder is prohibited. The 0.25 percent figure is a different limit, the weighted average lead content allowed on the wetted surfaces of pipe, fittings, and fixtures. The 2 percent and 8 percent values are far above any lead-free standard and describe legacy alloys no longer permitted.UPC §604.0

What is the maximum weighted average lead content permitted on the wetted surfaces of pipe, fittings, and fixtures used to convey water for human consumption?

• a.0.05 percent
• b.0.25 percent✓
• c.8 percent
• d.0.2 percent

The lead-free standard limits the wetted surfaces to a weighted average of not more than 0.25 percent lead. The 0.2 percent value is the separate limit that applies to solder and flux, not to the wetted surfaces of the components. The 0.05 percent figure is stricter than the code requires, and 8 percent describes older leaded brass that may no longer be installed in potable systems.

Static pressure at the main is 72 psi. Meter loss at design flow is 9 psi, the highest fixture is 26 ft above the meter, and 15 psi residual is required at that fixture. How much pressure is available to overcome friction loss in the piping?

• a.About 41.2 psi
• b.About 25.5 psi
• c.About 48.0 psi
• d.About 36.7 psi✓

Elevation loss is 26 x 0.433 = 11.26 psi, so 72 - 9 - 11.26 - 15 = 36.7 psi available for friction. The 48.0 psi answer forgets the required residual pressure, and 41.2 psi forgets part of the elevation loss. The 25.5 psi answer subtracts the residual twice or uses a 20 psi flushometer residual that this problem did not specify.UPC §610.0

A flushometer water closet on the top floor requires 20 psi residual. Static pressure is 65 psi, combined meter and backflow preventer loss is 10 psi, and the flush valve is 34 ft above the meter. How much pressure remains for friction loss in the piping and fittings?

• a.About 35.0 psi
• b.About 14.7 psi
• c.About 25.3 psi
• d.About 20.3 psi✓

Elevation loss is 34 x 0.433 = 14.72 psi, so 65 - 10 - 14.72 - 20 = 20.3 psi for friction. The 35.0 psi answer ignores the elevation loss, and 25.3 psi uses a 15 psi residual instead of the 20 psi a flushometer needs. The 14.7 psi choice is the elevation loss itself, not the friction allowance.UPC §610.0

A sizing problem leaves 24 psi available for friction loss. The measured developed length to the most remote fixture is 160 ft, and fittings are estimated to add 50 percent to that length. What is the allowable friction loss per 100 ft of pipe?

• a.About 6.7 psi per 100 ft
• b.About 10 psi per 100 ft✓
• c.About 24 psi per 100 ft
• d.About 15 psi per 100 ft

Total equivalent length is 160 x 1.5 = 240 ft, so 24 psi / 240 ft x 100 = 10 psi per 100 ft. The 15 psi answer divides by the measured 160 ft and skips the fitting allowance. The 6.7 psi answer overstates the equivalent length, and 24 psi per 100 ft simply restates the total budget without dividing by length.UPC §610.0

A dwelling unit contains one flush tank water closet (2.5 WSFU), two lavatories (1.0 WSFU each), one bathtub with shower (4.0 WSFU), one kitchen sink (1.5 WSFU), one dishwasher (1.5 WSFU), and one clothes washer (4.0 WSFU). What is the total water supply fixture unit load?

• a.16.5 WSFU
• b.15.5 WSFU✓
• c.14.5 WSFU
• d.13.0 WSFU

Adding the listed values gives 2.5 + 1.0 + 1.0 + 4.0 + 1.5 + 1.5 + 4.0 = 15.5 WSFU. The 14.5 answer counts only one lavatory, and 13.0 drops the dishwasher. The 16.5 answer adds an extra fixture unit that is not in the list; the total load is then carried into the sizing table to pick the service and distribution sizes.

Using the standard fixture unit to gpm conversion curve, what happens to the estimated demand when the total water supply fixture unit load on a system is doubled?

• a.The demand in gpm increases by less than double✓
• b.The demand in gpm more than doubles
• c.The demand in gpm exactly doubles
• d.The demand in gpm stays the same

The conversion curve is probability based: as more fixtures are added, the chance that all of them run at once drops, so gpm rises more slowly than fixture units. This diversity is why a 200 WSFU building does not need twice the flow of a 100 WSFU building. Assuming a straight-line doubling oversizes the service, and the more-than-double and no-change answers contradict how the curve behaves.IPC Appendix E

What is the minimum nominal size normally permitted for a water service pipe serving a building?

• a.5/8 in
• b.3/4 in✓
• c.1 in
• d.1/2 in

The water service pipe may not be smaller than 3/4 in regardless of what the fixture unit calculation produces. A 1/2 in service is below the code floor even for a very small single-fixture building, and 5/8 in is a meter size designation, not a standard pipe size. Requiring 1 in as the minimum is stricter than the code and would be a design choice, not a code requirement.

The highest fixture in a building is 28 ft above the meter and requires 15 psi residual. Meter loss is 5 psi and calculated friction loss in the piping is 12 psi. What minimum static pressure is needed at the meter?

• a.About 55.1 psi
• b.About 44.1 psi✓
• c.About 32.0 psi
• d.About 40.0 psi

Add every loss to the required residual: 28 x 0.433 = 12.12 psi elevation, plus 5 psi meter, plus 12 psi friction, plus 15 psi residual equals 44.1 psi. The 32.0 psi answer omits the elevation loss, and 40.0 psi rounds the elevation loss down to about 8 psi. The 55.1 psi answer double counts one of the losses and would call for a booster that is not actually needed.UPC §610.0

Using velocity (fps) = 0.408 x flow (gpm) divided by the square of the inside diameter (in), what is the velocity of 12 gpm flowing in 3/4 in Type L copper with an inside diameter of 0.785 in?

• a.About 10.2 fps
• b.About 6.0 fps
• c.About 4.4 fps
• d.About 7.9 fps✓

0.408 x 12 = 4.896, and 0.785 squared is 0.616, so 4.896 / 0.616 = 7.9 fps, right at the practical 8 fps cold water limit. The 4.4 and 6.0 answers come from dividing by the diameter instead of the diameter squared or from using the nominal 3/4 in size. The 10.2 answer uses a smaller inside diameter such as 0.69 in, which belongs to a heavier wall tube.

A 60 ft straight run of CPVC hot water pipe will see a 70 degree F temperature change. Using a coefficient of thermal expansion of 0.000034 in per in per degree F, approximately how much will the run expand?

• a.About 2.4 in
• b.About 1.7 in✓
• c.About 1.0 in
• d.About 0.6 in

Convert to inches first: 60 ft = 720 in, and 720 x 0.000034 x 70 = 1.71 in of movement, which is why an offset or expansion loop is needed. The 0.6 in and 1.0 in answers come from using only part of the temperature change or forgetting the foot-to-inch conversion. The 2.4 in answer uses a temperature change near 100 degrees F rather than the 70 degrees stated.

An existing galvanized steel water line is being extended with copper tube. What must be installed at the point where the two materials join?

• a.An approved dielectric fitting or dielectric union✓
• b.A rubber sleeve coupling with stainless steel clamps
• c.A soldered joint made directly to the steel pipe
• d.A brass compression coupling

Copper and galvanized steel are far apart on the galvanic scale, so a dielectric fitting is required to break the metallic path and prevent accelerated corrosion at the joint. A brass coupling still conducts and only shifts the corrosion cell rather than stopping it. Copper cannot be soldered directly to galvanized steel, and a rubber sleeve coupling is a drainage fitting that is not rated for water distribution pressure.IPC §605

What backflow protection is required on a typical residential exterior hose bibb (sillcock)?

• a.A listed hose-connection (atmospheric) vacuum breaker, nonremovable once installed✓
• b.A reduced-pressure principle backflow assembly on the branch feeding the sillcock
• c.A double check valve assembly installed ahead of the exterior wall penetration
• d.No device at all, since a garden hose is treated as a low-hazard connection

A hose bibb can be connected to a hose left in a pool of contaminated water, so it requires a listed hose-connection vacuum breaker to stop back-siphonage. A reduced-pressure assembly or double check is far more device than a single sillcock needs and is not the specified protection, and leaving it unprotected ignores a recognized cross-connection.IPC §608.15.4 / UPC §603

Where a water service pipe is laid near or in the same trench as the building sewer, the code requires:

• a.No separation is needed at all because both the water service and the sewer are pressure-rated pipes
• b.The sewer is laid above the water service so the potable water stays cooler in summer
• c.Both pipes are strapped tightly together in the trench so they share a single support
• d.The water service at least 12 inches above the sewer, on undisturbed earth, with the required setback✓

To keep sewage from contaminating the potable line if the sewer leaks, the water service must sit on solid undisturbed earth at least 12 inches above the top of the sewer, with a required horizontal separation (commonly 5 feet, but confirm the adopted code). Placing the sewer above the water service inverts the protection, no separation invites contamination, and strapping the pipes together defeats the vertical offset entirely.IPC §603.2 / UPC §720

Under the standard minimum fixture-supply table, what is the minimum nominal supply pipe size for a flushometer-valve water closet?

• a.3/8 inch
• b.1 inch✓
• c.1/2 inch
• d.3/4 inch

A flushometer water closet draws a very high instantaneous flow and requires a minimum 1 inch supply. A 3/8 inch supply serves a flush-tank water closet, 1/2 inch serves a lavatory or sink, and 3/4 inch is the minimum for a flushometer urinal, so each smaller size belongs to a different fixture.IPC Table 604.5 / UPC Table 610.4

Which joining method is NOT approved for PEX water tubing?

• a.Solvent-cement welded joints✓
• b.Insert fittings with copper crimp rings
• c.Cold-expansion fittings
• d.Insert fittings with stainless steel cinch clamps

PEX is joined only with mechanical fittings: cold-expansion, copper crimp rings, or stainless cinch clamps, all made to the listed PEX fitting standards. Solvent cement chemically fuses PVC, CPVC and ABS but does nothing to cross-linked polyethylene, so a solvent-welded PEX joint is not a recognized connection and would fail.IPC §605 / UPC §604

The minimum depth of cover (bury) for a water service pipe is governed primarily by:

• a.The local frost-line depth set by the authority having jurisdiction, to prevent freezing✓
• b.A single universal figure of 12 inches of cover required by every plumbing code
• c.A single universal figure of 6 feet of cover applied in every climate zone
• d.The pipe material by itself, independent of the local climate or frost depth

Burial depth is set by the local frost line so the service does not freeze, which is why the required cover differs sharply between a warm-winter region and a cold one. There is no single universal depth such as 12 inches or 6 feet, and the material of the pipe does not determine how deep freezing reaches; always confirm the depth with the authority having jurisdiction.IPC §305.4 / UPC §609

Static pressure at the meter is 72 psi and the highest fixture is 45 ft above the meter. Ignoring friction and meter loss, how much pressure remains at that fixture's elevation?

• a.46.5 psi
• b.38.5 psi
• c.52.5 psi✓
• d.58.8 psi

Elevation loss is 0.433 psi per foot of rise, so 45 ft x 0.433 = 19.5 psi, and 72 - 19.5 = 52.5 psi. Using a smaller factor gives 58.8 psi; the other values misapply the head-to-pressure relationship.

How many feet of vertical head are equivalent to 35 psi of water pressure?

• a.15.2 ft
• b.35 ft
• c.80.9 ft✓
• d.70 ft

One psi equals 2.31 ft of head, so 35 x 2.31 = 80.9 ft. 15.2 ft divides by 2.31 instead of multiplying, 35 ft ignores the conversion, and 70 ft uses a factor of 2.0.

A storage tank's water surface is 90 ft above an outlet. Ignoring friction, what static pressure does that elevation produce at the outlet?

• a.39 psi✓
• b.208 psi
• c.90 psi
• d.19.5 psi

Pressure equals head times 0.433 psi per foot, so 90 x 0.433 = 39 psi. 208 psi multiplies by 2.31 (the inverse factor), 90 psi treats feet as psi, and 19.5 psi halves the correct value.

A potable supply outlet has an effective opening of 1/2 in and discharges over a receptor. What is the minimum required air gap?

• a.1 in✓
• b.1/2 in
• c.3/4 in
• d.1-1/2 in

The air gap must be at least twice the effective opening, so 2 x 1/2 in = 1 in, which also meets the 1 in absolute minimum (IPC 608.15.1). 1/2 in and 3/4 in are below the calculated and minimum values, and 1-1/2 in exceeds what this opening requires.

A potable supply outlet has an effective opening of 3/4 in. What is the minimum required air gap above the flood level rim?

• a.2 in
• b.3/4 in
• c.1-1/2 in✓
• d.1 in

Twice the effective opening is 2 x 3/4 in = 1-1/2 in, which is above the 1 in absolute minimum, so 1-1/2 in governs (IPC 608.15.1). 3/4 in and 1 in are too small and 2 in is more than required.

Static pressure is 70 psi, meter loss is 8 psi, the highest fixture is 30 ft above the meter, and 15 psi residual is required there. How much pressure remains for friction loss in the piping?

• a.40.0 psi
• b.21.0 psi
• c.34.0 psi✓
• d.47.0 psi

Elevation loss is 30 x 0.433 = 13 psi, so 70 - 8 - 13 - 15 = 34 psi available for friction. 47.0 psi omits the elevation loss, 40.0 psi understates it, and 21.0 psi subtracts an extra loss.

A sizing problem leaves 26 psi available for friction. The measured developed length to the most remote fixture is 160 ft and fittings are estimated to add 50 percent. What is the allowable friction loss per 100 ft of pipe?

• a.26 psi per 100 ft
• b.6.5 psi per 100 ft
• c.16.3 psi per 100 ft
• d.10.8 psi per 100 ft✓

Total equivalent length is 160 x 1.5 = 240 ft, so 26 / 240 x 100 = 10.8 psi per 100 ft. 16.3 uses only the measured 160 ft, 6.5 overstates the equivalent length, and 26 skips the division by length.

A dwelling has one flush-tank water closet (2.5 WSFU), one bathtub with shower (2.0 WSFU), one lavatory (1.0 WSFU), one kitchen sink (1.5 WSFU), and one clothes washer (4.0 WSFU). What is the total water supply fixture unit load?

• a.12.5 WSFU
• b.10.0 WSFU
• c.11.0 WSFU✓
• d.9.0 WSFU

Adding the listed values: 2.5 + 2.0 + 1.0 + 1.5 + 4.0 = 11.0 WSFU. 9.0 and 10.0 drop a fixture, and 12.5 adds load not in the list. The total is then read against the sizing table.

Using velocity (fps) = 0.408 x flow (gpm) / inside diameter squared (in), what is the velocity of 8 gpm in 1/2 in Type L copper with an inside diameter of 0.545 in?

• a.6.0 fps
• b.5.5 fps
• c.8.0 fps
• d.11.0 fps✓

0.408 x 8 = 3.264, and 0.545 squared is 0.297, so 3.264 / 0.297 = 11.0 fps, well above the practical 8 fps cold-water limit, which shows 1/2 in is too small for 8 gpm. The lower answers divide by the diameter rather than its square.

The highest fixture is 35 ft above the meter and needs 15 psi residual, meter loss is 6 psi, and friction loss is 14 psi. What minimum static pressure is needed at the meter?

• a.35.0 psi
• b.50.2 psi✓
• c.44.0 psi
• d.29.0 psi

Add every loss to the residual: 35 x 0.433 = 15.2 psi elevation, plus 6 meter, plus 14 friction, plus 15 residual = 50.2 psi. 35.0 omits the elevation loss and 44.0 understates it.

An 80 ft straight run of CPVC will see a 80 degree F temperature change. Using a thermal-expansion coefficient of 0.000034 in per in per degree F, about how much will it move?

• a.1.3 in
• b.3.9 in
• c.0.9 in
• d.2.6 in✓

Convert to inches: 80 ft = 960 in, and 960 x 0.000034 x 80 = 2.6 in, so an offset or expansion loop is needed. 1.3 in halves the movement and 3.9 in overstates the temperature change.

Under IPC Table 604.3, what minimum flow pressure is required at a flushometer-valve water closet?

• a.8 psi
• b.25 psi✓
• c.35 psi
• d.15 psi

A flushometer-valve water closet requires about 25 psi minimum flow pressure to operate the valve (IPC Table 604.3), far more than a tank fixture. 8 psi is the lavatory requirement, and 15 psi and 35 psi are not the tabulated value for this fixture.

Under IPC Table 604.3, what minimum flow pressure is required at a lavatory faucet?

• a.15 psi
• b.8 psi✓
• c.20 psi
• d.4 psi

A lavatory faucet requires a minimum flow pressure of about 8 psi (IPC Table 604.3). 4 psi is below the tabulated value, and 15 psi and 20 psi are higher than a lavatory needs (closer to flushometer requirements).

A chemical feed connection to the potable supply is a high-hazard (health) cross-connection subject to back-pressure under continuous pressure. Which device is required?

• a.A reduced pressure principle assembly✓
• b.A double check valve assembly
• c.A pressure vacuum breaker
• d.An atmospheric vacuum breaker on the branch

A high-hazard connection with back-pressure under continuous pressure requires a reduced pressure principle assembly (IPC 608.13.2). A double check is only for low hazard, and vacuum breakers protect against back-siphonage, not back-pressure.

An atmospheric vacuum breaker (AVB) may NOT have which of the following?

• a.A fixture or outlet located below it on the same branch that it protects against back-siphonage
• b.Copper piping upstream
• c.A hose thread outlet
• d.Any valve downstream of it, and it may not be under continuous pressure for more than 12 hours✓

An AVB relies on atmospheric venting, so no shutoff valve may be located downstream of it and it may not be under continuous pressure for more than 12 hours (IPC 608.13.6). Upstream piping material and a downstream fixture do not disqualify it.

How does a pressure vacuum breaker (PVB) differ from an atmospheric vacuum breaker?

• a.It needs no minimum installation height
• b.It protects against both back-pressure and back-siphonage, so it may be used on any cross-connection regardless of the hazard level involved
• c.It is for back-pressure only
• d.It may be installed under continuous pressure and has test cocks and a spring-loaded check, but protects only against back-siphonage✓

A PVB has a spring-loaded air inlet and check plus test cocks, so it may stay under continuous pressure and can be tested, unlike an AVB. It still protects only against back-siphonage, not back-pressure, and must be at least 12 in above the highest downstream outlet.

Which material is NOT approved for hot-water distribution piping?

• a.PEX
• b.CPVC
• c.Type L copper
• d.PVC✓

PVC is rated for cold-water and DWV service only and will soften and fail on hot water; CPVC is the chlorinated version made for hot water. Type L copper and PEX are both approved for hot-water distribution.

Before a new potable water line is placed in service, it must be:

• a.Left as installed
• b.Filled with hot water
• c.Pressure tested with air only, then placed directly in service
• d.Disinfected (chlorinated) and flushed✓

New potable water piping must be disinfected with a chlorine solution and then flushed before use to remove contamination introduced during installation (IPC 610.1). A pressure test alone does not sanitize the pipe.

What must be provided on the water service near where it enters the building?

• a.Only a pressure-reducing valve, with no separate shutoff on the service
• b.Only a check valve
• c.No valve at all
• d.An accessible main shutoff valve on the water service✓

A full-open, accessible main shutoff valve is required on the water service so the whole building supply can be isolated (IPC 606.1). A check valve or a pressure-reducing valve serves a different purpose and does not satisfy the main-shutoff requirement.

What does the code require at each individual fixture supply?

• a.A check valve at each fixture
• b.A single shutoff valve at the main, which serves all of the fixtures at once
• c.An accessible shutoff (stop) valve on each fixture supply✓
• d.No shutoffs at fixtures

Each fixture supply must have an accessible individual stop valve so the fixture can be serviced without shutting down the whole building (IPC 606.2 lists where stops are required). A single main shutoff does not meet the individual-fixture requirement.

Why are listed mechanical water-hammer arrestors preferred over plain air chambers?

• a.Air chambers are illegal
• b.There is no difference
• c.Air chambers are cheaper
• d.Plain air chambers waterlog and lose their air cushion over time, while listed arrestors keep their charge✓

A capped-pipe air chamber gradually absorbs its air into the water and waterlogs, losing its cushion, whereas a listed mechanical arrestor keeps a sealed air or gas charge. That reliability is why arrestors are specified for quick-closing valves.

In water-service sizing, how is the pressure lost through the water meter handled?

• a.Ignored
• b.Relevant only for wells
• c.Subtracted from the available pressure before sizing the piping✓
• d.Added to the available pressure, since the meter is said to boost downstream flow

Meter pressure loss at design flow is one of the deductions taken from the static supply pressure, along with elevation, residual, and backflow-device losses, before the remainder is left for pipe friction. Ignoring it oversizes the friction budget and undersizes the pipe.

For water-distribution sizing, the developed length is measured:

• a.Along the actual pipe run to the most remote fixture✓
• b.To the nearest fixture
• c.As only the vertical rise
• d.As the straight-line (as-the-crow-flies) distance to the most remote fixture

Developed length is measured along the centerline of the pipe, following every offset, to the most hydraulically remote fixture, since that path governs friction loss. A straight-line or nearest-fixture measurement understates the run.

What is the generally accepted maximum design velocity for a cold-water distribution line?

• a.5 fps
• b.12 fps
• c.8 fps✓
• d.15 fps

Cold-water lines are commonly designed to a maximum of about 8 fps to limit noise and erosion; hot-water lines are held lower, near 5 fps. 12 fps and 15 fps are well above accepted practice and cause velocity noise and pipe wear.

A common method of disinfecting new potable piping uses a chlorine concentration and contact time of about:

• a.5 ppm for 1 hour
• b.No minimum concentration is specified; a simple flush with clean water is enough
• c.50 ppm held about 24 hours (or 200 ppm for about 3 hours)✓
• d.500 ppm for 10 minutes

A typical disinfection procedure charges the system to at least 50 ppm chlorine for about 24 hours, or a stronger 200 ppm for about 3 hours, then flushes and confirms an acceptable residual (IPC 610.1). A brief 5 ppm dose is too weak and short.

What is the minimum supply pipe size for a hose bibb (sillcock)?

• a.1 in
• b.3/8 in
• c.1/4 in
• d.1/2 in✓

A hose bibb requires a minimum 1/2 in supply (IPC Table 604.5). 1/4 in and 3/8 in are undersized, and 1 in is far larger than a single sillcock needs.

A water-distribution system is tested with water at not less than its working pressure. For how long must the pressure hold with no drop?

• a.15 minutes✓
• b.1 hour
• c.5 minutes
• d.10 minutes

The water-supply test holds at not less than the working pressure for at least 15 minutes with no loss of pressure (IPC 312.5). Any drop indicates a leak; 5 or 10 minutes is short of the required duration.

A lawn irrigation system injects fertilizer or chemicals into the water. What backflow protection does this high-hazard connection require?

• a.A double check valve assembly on the irrigation branch
• b.A reduced pressure principle assembly✓
• c.An atmospheric vacuum breaker
• d.A pressure vacuum breaker

Chemical injection makes irrigation a high-hazard (health) connection, and where it is under continuous pressure or subject to back-pressure it requires a reduced pressure principle assembly (IPC 608.13.2). A vacuum breaker or double check does not protect a high-hazard, back-pressure connection.

Which materials are commonly used for an underground water service?

• a.CPVC only
• b.Type M copper only
• c.Type K copper or PE plastic✓
• d.Galvanized steel pipe only, because it resists corrosion in soil

Underground water services are commonly Type K copper (the heaviest wall) or polyethylene (PE) plastic, both suited to burial (IPC 605 / UPC 604). Type M is generally restricted to above-ground use, and galvanized steel corrodes in soil.

Which provides the most positive, reliable backflow protection for a cross-connection?

• a.An atmospheric vacuum breaker
• b.A pressure vacuum breaker
• c.An air gap (a physical separation)✓
• d.A double check valve assembly

An air gap is a physical vertical separation of at least twice the supply-opening diameter and cannot fail mechanically, so it is the most reliable backflow protection (IPC 608.15.1). Mechanical assemblies rely on checks and springs that can wear.

Where must a lavatory faucet spout be located relative to the flood level rim of the basin?

• a.At the flood level rim
• b.Below the flood level rim
• c.Above the flood level rim to maintain an air gap✓
• d.Submerged in the basin

The faucet spout must terminate above the flood level rim of the fixture so that if the basin fills and the supply loses pressure, contaminated water cannot be siphoned back through the spout (IPC 608.15.1). A spout at or below the rim creates a submerged-inlet cross-connection.

A flushometer valve must be provided with what backflow protection?

• a.An air gap only
• b.An integral (built-in) vacuum breaker✓
• c.A check valve only
• d.No backflow protection

A flushometer discharges below the rim of the fixture, so it must have an integral vacuum breaker downstream of the valve to prevent back-siphonage of fixture water into the supply (IPC 608.15.4). A plain check valve does not provide this protection.