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The TX-MP exam has 308 questions and runs 6 hours.
These 10 free TX-MP questions are organized by exam domain, so you can see how each part of the Texas Master Plumber License Exam blueprint is tested. Reveal the answer and explanation under each question.
At a restaurant ice machine, the bin's meltwater drain ends below the floor sink's flood-level rim but above the standing water in its trap. The installer calls this an air break and says it is sufficient because the floor sink is separately trapped and vented. Under the 2018 IPC, how should the meltwater connection be corrected?
Correct answer: D - Terminate the waste above the flood-level rim with the required air gap.
An upper-floor fixture must receive at least 20 psi while 12 gpm flows. Immediately upstream of the meter and backflow assembly, pressure is 75 psi with no flow and 55 psi at 12 gpm. The fixture is 20 feet higher; meter and backflow losses total 8 psi at that flow. Calculated pipe-friction losses for the complete route at 12 gpm are: 3/4 inch, 24 psi; 1 inch, 10 psi; 1-1/4 inches, 4 psi; 1-1/2 inches, 2 psi. Use 0.433 psi per foot of elevation. No other minimum-size requirement governs. What is the smallest listed pipe that delivers the required fixture pressure without a booster?
Correct answer: B - 1 inch
A continuously pressurized potable-water line supplies a chemical process that presents a health hazard. A process pump can raise downstream pressure to 85 psi while the potable supply is at 60 psi. Where an approved mechanical backflow assembly is permitted instead of an air gap, which device addresses both the hazard and the possible direction of pressure reversal?
Correct answer: B - A reduced-pressure-principle assembly listed to ASSE 1013.
After a backflow assembly is added to a building's water service, pressure at the storage water heater rises from 62 psi to 118 psi during recovery with all fixtures closed. Supply pressure upstream of the assembly stays at 62 psi. The burner shuts off at the normal temperature setting, and briefly opening a hot-water faucet brings the heater pressure back down. Which condition best explains the readings?
Correct answer: C - Heated water is expanding in a closed system without effective expansion control.
A same-floor bathroom group is correctly arranged for horizontal wet venting under the 2018 IPC. A proposed laundry branch, which has its own dry vent, joins the wet-vented segment between the lavatory and water-closet connections. The pipe has enough drainage capacity for the added load. To retain the bathroom group's horizontal wet vent, the laundry connection must be:
Correct answer: A - Relocated to a point downstream of the entire horizontal wet-vented section.
On a project governed by the 2018 UPC, a utility sink's 2-inch trap arm measures 4 feet 6 inches from the trap weir to the vent opening and slopes 1/4 inch per foot. All other trap-arm details comply. A foreman requests a closer vent because he remembers a 3-foot-6-inch limit. Which response correctly applies the code to this installation?
Correct answer: D - Retain this installation; the 2-inch trap arm is within its 5-foot length limit.
A new single-family dwelling's steel gas piping is designed for a maximum working pressure of 0.5 psig. With appliances properly isolated and the pressure source disconnected, the piping holds a 3-psig air test for 10 minutes after temperature stabilization. The calibrated mechanical gauge has a 0-100-psig scale. Applying the unamended 2018 IFGC, how should the test be handled?
Correct answer: A - Repeat the 3-psig test using a suitable calibrated 0-10-psig mechanical gauge.
A Texas plumbing company has an active Responsible Master Plumber (RMP) and a permitted restaurant project. Its most experienced residential installer holds an active Tradesman Plumber-Limited license but no Journeyman license. Which assignment is within that installer's authorized scope on this commercial project?
Correct answer: D - Assist with installation under an on-site Journeyman or Master Plumber's supervision.
Before workers enter a 4-foot-8-inch-deep service trench after overnight rain, the competent person finds fresh tension cracks and soil sloughing from one wall. The trench has no cave-in protective system. A ladder is within 10 feet, and spoil is set back 3 feet. The foreman argues that protection begins at 5 feet. What must happen before entry resumes?
Correct answer: B - Provide an adequate cave-in protective system before allowing workers to enter.
The shop drawing for an adult wheelchair-accessible toilet compartment in a new public restroom shows a floor-mounted water closet. Finished inside dimensions are 62 inches wide by 57 inches deep; the water-closet centerline is 17 inches from the side wall, and the seat top is 18 inches above the floor. Door, grab-bar, and toe-clearance details comply. The drawing is returned for one dimensional correction under the 2012 Texas Accessibility Standards. Which comment belongs on the review?
Correct answer: C - Increase the finished compartment depth to at least 59 inches.
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