10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The AL-MP exam has 100 questions and runs 4.17 hours.
These 10 free AL-MP questions are organized by exam domain, so you can see how each part of the Alabama Master Plumber Exam blueprint is tested. Reveal the answer and explanation under each question.
A continuously pressurized makeup-water line supplies a chemical mixing system containing a toxic additive. The process pump can raise the chemical-side pressure above the potable supply pressure. Of these devices, which provides the necessary backflow protection?
Correct answer: A - A reduced-pressure-principle backflow prevention assembly.
A cold-water service design changes from Schedule 40 PVC to Schedule 80 PVC of the same nominal size. Both products are approved for the service, and the required flow is unchanged. Which statement correctly describes the hydraulic effect of this substitution?
Correct answer: C - The smaller inside diameter increases water velocity, raising friction loss at the specified flow rate.
Drainage drawings for a new building show lower-floor fixtures at finished-floor elevation 96.4 ft and upper-floor fixtures at 106.4 ft. The next upstream public-sewer manhole cover is at 99.0 ft; the next downstream cover is at 94.0 ft. All elevations use the same benchmark. Which backwater-valve arrangement belongs on the riser diagram under the 2021 IPC?
Correct answer: B - Place a backwater valve on the lower-floor branch; let the upper-floor branch bypass it.
For an upper-floor fixture, the service connection measures 74 psi static and 58 psi while delivering the design flow. The fixture is 30 ft above that connection and requires 35 psi while operating. At design flow, pipe and fitting losses total 8 psi, and a backflow assembly adds 6 psi. Use 0.433 psi per foot of water elevation. Which pressure estimate and design assessment are correct?
Correct answer: B - About 31 psi at the fixture; the proposed layout falls short of its operating requirement.
Two connections are visible at rough-in: a horizontal, individually vented lavatory drain enters a vertical stack through an upright sanitary tee; a separate horizontal branch enters a horizontal drain through a sanitary tee turned sideways in the horizontal plane. Both fittings point in the direction of flow, and the pipe sizes and grades are satisfactory. Under the 2021 IPC, the proper inspection disposition is to:
Correct answer: D - Retain the upright tee; replace the horizontal-to-horizontal tee with a combination wye and eighth bend.
A copper water-supply section has a 60-psi working pressure. It is filled from a potable source and holds 65 psi for 20 minutes without leakage. The manufacturer and project specifications impose no additional test pressure or duration. For the pressure test alone, what is the correct disposition under 2021 IPC Section 312.5?
Correct answer: D - Accept the pressure test; neither a higher-pressure nor a longer-duration retest is required.
A kitchen needs continuous recovery of 65 gallons per hour from 55°F to 135°F; stored hot water cannot be credited toward this sustained demand. Four otherwise suitable heaters have the input ratings listed below, each with 80% thermal efficiency. Use 8.34 Btu to raise 1 gallon of water by 1°F and neglect other losses. Select the smallest input rating that can meet the load.
Correct answer: C - 60,000 Btu/h input.
An electric water heater is locked out, absence of voltage is verified, and both wires are disconnected from one heating element. The manufacturer's acceptable terminal-to-terminal resistance is 12 to 14 ohms. A checked ohmmeter reads 12.8 ohms between the terminals and 4.0 ohms from one terminal to the metal flange. Taken together, these readings identify:
Correct answer: A - A grounded element despite an intact terminal-to-terminal heating path.
A storage water heater has been shut down after repeated pressure-relief discharge. Cold pressure holds at 56 psi with the heater off, but rises above 150 psi during recovery; water temperature remains normal. The cold-supply piping runs from the main to an expansion-tank connection, then through a recently added check valve to the heater. Which correction addresses the cause of the pressure rise?
Correct answer: C - Reconnect the expansion tank between the check valve and the water heater.
A bathroom's horizontal wet vent serves a lavatory, shower, and water closet on one floor. The lavatory is dry vented, and the bathroom fixture drains connect independently in the permitted sequence. An individually vented kitchen sink has been added between the lavatory and water-closet connections. The wet-vent pipe has adequate load capacity. What must change to retain a compliant bathroom wet vent?
Correct answer: B - Move the kitchen drain connection downstream of the entire bathroom wet-vented section.
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