Tennessee Plumbing (CMC-A) Contractor Examination

Per the 2021 International Plumbing Code, the building drain becomes the building sewer at which point?

• AAt the first cleanout inside the foundation wall
• B30 inches in developed length of pipe beyond the exterior walls of the building
• C10 feet beyond the exterior walls of the building
• DAt the public sewer tap, regardless of developed length

A drainage fixture unit (DFU) as used in the 2021 IPC is best described as which of the following?

• AThe measured gallons per minute discharged by a fixture at peak flow
• BA relative load value assigned to a fixture to estimate probable drainage load on a pipe
• CThe trap diameter of the fixture expressed as a whole number
• DThe number of occupants that may use one public water closet

The primary purpose of a fixture trap is to do which of the following?

• AIncrease the velocity of waste so solids do not settle
• BProvide a water seal that prevents sewer gas from entering the building
• CStrain solids so they never enter the drainage piping
• DServe as the required vent for the fixture drain

Developed length of piping, as used for IPC vent and water-supply calculations, is measured in which manner?

• AThe straight-line horizontal distance between the two endpoints
• BThe length along the pipe centerline, including fittings, between the two points consider…
• CThe vertical rise only, ignoring horizontal offsets
• DThe sum of fitting equivalent lengths only, ignoring the pipe itself

A cross-connection in a potable water system is best defined as which of the following?

• AAny tee that joins a hot-water branch to a cold-water branch at a mixing valve
• BAn actual or potential connection between potable water and a source of contamination or…
• CA dielectric union between dissimilar metals
• DA water-service pipe that shares a trench with a building drain of approved material

Atmospheric pressure at sea level will support a water column of approximately which height, which is why a suction lift pump has a practical limit well below that theoretical value?

• A14.7 feet
• B23.0 feet
• C33.9 feet
• D43.3 feet

A 40-foot horizontal building drain is installed at a uniform slope of 1/4 inch per foot. What is the total fall from the upstream end to the downstream end?

• A5 inches
• B8 inches
• C10 inches
• D12 inches

A 45-degree offset must gain 8 inches of offset. Using the standard 45-degree travel constant of 1.414, what is the center-to-center travel of the offset piece?

• A8.0 inches
• B9.2 inches
• C11.3 inches
• D16.0 inches

A water column 28 feet high stands on a gauge at the base of a riser. Using 0.433 psi per foot of water, what is the static pressure at the gauge?

• A6.5 psi
• B12.1 psi
• C16.2 psi
• D28.0 psi

A dwelling contains two private bathroom groups that use 1.6-gpf water closets, one domestic kitchen sink, and one residential clothes washer. Using 2021 IPC Table 709.1, what is the total drainage fixture-unit load?

• A10 DFU
• B12 DFU
• C14 DFU
• D16 DFU

A 22-1/2-degree offset must gain 6 inches of offset. Using the 22-1/2-degree travel constant of 2.613, what is the center-to-center travel, rounded to the nearest tenth of an inch?

• A8.5 inches
• B12.0 inches
• C15.7 inches
• D18.4 inches

A 4-inch-diameter cylindrical tank is 6 feet long and is completely full of water. Using V = πr²h with r = 2 inches (0.167 ft) and 7.48 gallons per cubic foot, about how many gallons does the tank hold?

• A3.9 gallons
• B5.2 gallons
• C7.8 gallons
• D12.5 gallons

Per 2021 IPC Section 312.2, a drainage and vent water test shall hold a 10-foot head of water for not less than which duration?

• A5 minutes
• B10 minutes
• C15 minutes
• D30 minutes

Per 2021 IPC Table 704.1, what is the minimum slope of horizontal drainage piping that is 2-1/2 inches or smaller (except piping upstream of a grease interceptor)?

• A1/16 inch per foot
• B1/8 inch per foot
• C1/4 inch per foot
• D1/2 inch per foot

Per 2021 IPC Section 708, horizontal drainage piping shall be provided with cleanouts located not more than how far apart?

• A50 feet
• B75 feet
• C100 feet
• D150 feet

Per 2021 IPC Section 603.2, underground water service pipe and the building sewer shall ordinarily be separated by not less than which distance of undisturbed or compacted earth?

• A12 inches
• B2 feet
• C5 feet
• D10 feet

Per 2021 IPC Section 1002.4, each fixture trap shall have a water seal of not less than 2 inches and not more than which depth?

• A3 inches
• B4 inches
• C6 inches
• D8 inches

Per 2021 IPC Section 604.8, a water-pressure reducing valve conforming to ASSE 1003 or CSA B356 is required where static pressure at the building exceeds which value?

• A60 psi
• B80 psi
• C100 psi
• D150 psi

Per 2021 IPC Section 607.2, a method of maintaining hot-water temperature (recirculation, heat trace, or equivalent) is required when the developed length of hot-water piping from the source to the farthest fixture exceeds which distance?

• A25 feet
• B50 feet
• C75 feet
• D100 feet

Per 2021 IPC Table 706.3, a sanitary tee is permitted in which drainage-pattern application?

• AHorizontal to horizontal change of direction
• BHorizontal to vertical change of direction
• CVertical to horizontal change of direction
• DDouble sanitary tee on its back as a horizontal double wye

Per 2021 IPC Section 903.1, an open vent pipe that extends through a roof that is not used as a deck or promenade shall terminate not less than how far above the roof?

• A2 inches
• B6 inches
• C12 inches
• D7 feet

Per 2021 IPC Section 903.5, a vent terminal shall be located not less than 10 feet horizontally from, or not less than which height above, any openable window, door, or air intake?

• A6 inches
• B12 inches
• C3 feet
• D10 feet vertically

Per 2021 IPC Section 405.3.1, a water closet shall not be set closer than which distance from its centerline to a side wall, partition, or vanity?

• A12 inches
• B15 inches
• C18 inches
• D21 inches

Per 2021 IPC Table 709.1, what is the minimum trap size and drainage fixture-unit value for a private lavatory?

• A1-1/4 inch trap, 1 DFU
• B1-1/4 inch trap, 2 DFU
• C1-1/2 inch trap, 1 DFU
• D1-1/2 inch trap, 2 DFU

Per 2021 IPC Table 604.5, what is the minimum fixture supply-pipe size for a flushometer-valve water closet?

• A3/8 inch
• B1/2 inch
• C3/4 inch
• D1 inch

Per 2021 IPC Section 504.6, the discharge pipe from a water-heater temperature-and-pressure relief valve shall do which of the following?

• ABe directly connected to the sanitary drainage system with a trapped adapter
• BDischarge through an air gap in the same room and shall not be smaller than the valve out…
• CBe reduced one size after the first elbow to limit scalding splash
• DBe threaded at the outlet so a hose can be attached for testing

Per 2021 IPC Section 504.5, a temperature-and-pressure relief valve shall have a temperature setting of not more than which value?

• A120°F
• B180°F
• C210°F
• D250°F

Per 2021 IPC Section 504.7, where a storage water heater is installed in a location where leakage would cause damage, a drain pan is required. The pan drain shall be not less than which size?

• A1/2 inch
• B3/4 inch
• C1 inch
• D1-1/4 inch

Per 2021 IPC Table 1106.2, what is the maximum capacity of a 4-inch vertical storm drain?

• A87 gpm
• B115 gpm
• C163 gpm
• D180 gpm

A projected roof area of 2,000 square feet is designed for a rainfall intensity of 3 inches per hour. Using the conversion 1 in/hr on 1 ft² = 0.0104 gpm, what is the design storm flow, and what is the smallest vertical leader from Table 1106.2 that will carry it?

• A20.8 gpm; 2-inch vertical
• B41.6 gpm; 2-inch vertical
• C62.4 gpm; 3-inch vertical
• D62.4 gpm; 2-inch vertical

Per 2021 IPC Section 1106.4, when a vertical wall diverts rainwater onto a roof, how much of that wall area shall be added to the projected roof area for conductor and storm-drain sizing?

• ANone of the wall area
• BOne-fourth of the wall area
• COne-half of the wall area
• DThe entire wall area

A 4-inch horizontal storm drain at 1/8 inch per foot can carry 115 gpm (Table 1106.2). If field conditions force the same 4-inch line to be laid at 1/8 inch per foot for a calculated 140 gpm roof flow, what is the correct action?

• ALeave the 4-inch pipe; storm drains may run 25 percent over table capacity
• BIncrease the slope to 1/4 inch per foot so the 4-inch capacity becomes 163 gpm, or increa…
• CReduce the pipe to 3-inch to raise velocity
• DConvert the storm drain to a combined sanitary sewer so Table 710.1(1) applies

Per IFGC Section 406.4.1, the test pressure on a fuel-gas piping system shall be not less than 1-1/2 times the proposed maximum working pressure and not less than which minimum?

• A1 psig for 5 minutes
• B3 psig
• C10 psig for every system, regardless of volume
• D60 psig for all residential piping

Per IFGC Section 408.4, where a sediment trap is not built into the appliance, it shall be installed in which location?

• AUpstream of the appliance shutoff valve, as close to the meter as practical
• BDownstream of the appliance shutoff valve, as close to the appliance inlet as practical
• COnly on the house side of the gas meter, one trap per building
• DOnly on undiluted propane systems

Per IFGC Section 409.5, an appliance shutoff valve shall be in the same room as the appliance and within what maximum distance of the appliance?

• A3 feet
• B6 feet
• C10 feet
• D25 feet

Per IFGC Section 310.2, yellow (non-arc-resistant) CSST gas piping shall be bonded to the electrical service grounding-electrode system with a copper bonding jumper not smaller than which size?

• A10 AWG copper
• B8 AWG copper
• C6 AWG copper
• D4 AWG aluminum only

Per IFGC Section 404.12, underground fuel-gas piping shall have a minimum cover of which depth, except as provided for individual outdoor appliances?

• A6 inches
• B8 inches
• C12 inches
• D18 inches

Using IFGC Table 402.4(2) (Schedule 40 metallic pipe, natural gas, less than 2 psi, 0.5 inch w.c. drop, specific gravity 0.60), a 50-foot longest length can carry 151 cfh in 3/4-inch pipe and 284 cfh in 1-inch pipe. A 199,000 Btu/h tankless heater on 1,000 Btu/ft³ gas needs which minimum pipe size on that 50-foot run?

• A1/2 inch
• B3/4 inch
• C1 inch
• D1-1/4 inch

A low-pressure natural-gas system has a 40,000 Btu/h water heater, an 80,000 Btu/h furnace, and a 65,000 Btu/h range. Gas is 1,000 Btu/ft³. Using the longest-length method and Table 402.4(2) capacities at 50 feet (3/4 inch = 151 cfh, 1 inch = 284 cfh), what size Schedule 40 steel main is required from the meter?

• A1/2 inch
• B3/4 inch
• C1 inch
• D2 inch

When sizing a low-pressure gas system by the IFGC longest-length method, a 12-foot branch to a nearby water heater on a system whose farthest appliance is 70 feet from the meter is sized from which table row?

• AThe 10-foot row, because the branch itself is 12 feet
• BThe 20-foot row, rounding the 12-foot branch up
• CThe 70-foot row (or the next longer published length), the same row used for every section
• DAn average of 12 feet and 70 feet

Per IFGC Table 415.1, what is the maximum horizontal support spacing for 1/2-inch steel gas pipe?

• A4 feet
• B6 feet
• C8 feet
• D10 feet

Per IFGC Section 406.4.2, the minimum test duration for a fuel-gas piping system in a single-family dwelling, or for any system whose volume is less than 10 cubic feet, is which of the following?

• A5 minutes
• B10 minutes
• C30 minutes for every dwelling, regardless of volume
• D24 hours

Per OSHA 29 CFR 1926.652, a protective system (sloping, benching, shoring, or shielding) is required for trenches at which depth, unless the excavation is entirely in stable rock?

• A4 feet
• B5 feet
• C6 feet
• D20 feet

Per OSHA 29 CFR 1926.651, a stairway, ladder, ramp, or other safe means of egress is required in trench excavations at which depth, and it shall be located so that no more than how much lateral travel is required?

• A4 feet deep; 25 feet of lateral travel
• B5 feet deep; 25 feet of lateral travel
• C4 feet deep; 50 feet of lateral travel
• D5 feet deep; 10 feet of lateral travel

Per OSHA 1926 Subpart P Appendix B, the maximum allowable slope for Type C soil in an excavation 20 feet deep or less is which of the following?

• AVertical (90 degrees)
• B3/4 horizontal to 1 vertical (53 degrees)
• C1 horizontal to 1 vertical (45 degrees)
• D1-1/2 horizontal to 1 vertical (34 degrees)

Per OSHA 1926.651, excavated spoil and other materials shall be kept at least how far from the edge of an excavation?

• A12 inches
• B2 feet
• C4 feet
• D5 feet