Master Plumber (UPC/IPC) Practice Test

Câu hỏi luyện tập mẫu

Một vài câu hỏi thực tế từ ngân hàng miễn phí này, kèm giải thích đầy đủ. Dùng công cụ luyện tập ở trên cho toàn bộ.

1. 1. Design & Sizing

   A residential branch serves the following fixtures with these water-supply fixture unit (WSFU) values: 8 water closets (tank) at 2.5 each, 8 lavatories at 1 each, and 8 showers at 2 each. What is the total demand load on the branch?

   • a.60 WSFU
   • b.36 WSFU
   • c.52 WSFU
   • d.44 WSFU

   Đáp án: c

   Giải thích: Multiply each fixture count by its WSFU value and add: (8 x 2.5) + (8 x 1) + (8 x 2) = 20 + 8 + 16 = 52 WSFU. This total is what you carry into a Hunter-curve demand chart to convert fixture units to gpm. Using the wrong per-fixture value is the usual cause of a low answer such as 44.

   Nguồn: UPC §610.0

2. 2. Systems & Code

   An air gap is used to protect a potable outlet discharging over a flood-level rim. What is the minimum air gap for an effective opening of 1 in diameter, using the rule of two times the effective opening?

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

   Đáp án: c

   Giải thích: The minimum air gap is twice the effective opening diameter, so 2 x 1 in = 2 in, and never less than 1 in in any case. The air gap is the most reliable backflow protection because it is a physical break that cannot fail mechanically. Near a wall the multiplier increases to three times the opening.

   Nguồn: UPC §603.4.6

3. 3. Administration

   A rough-in inspection fails because a required cleanout was omitted at the base of a stack. What is the master plumber's correct response?

   • a.Argue the cleanout is optional
   • b.Cover the work and note it on the final
   • c.Remove the stack entirely
   • d.Install the cleanout and request a re-inspection before concealment

   Đáp án: d

   Giải thích: The correct response is to install the missing cleanout as required and call for a re-inspection before the work is covered, because the code requires a cleanout at the base of each stack. Concealing a known deficiency risks failing the final and being ordered to open the wall. Corrective work plus re-inspection keeps the project compliant.

   Nguồn: UPC §103.5

4. 4. Design & Sizing

   At a rainfall rate of 1 in/hr, how many gpm does 1,000 ft^2 of roof produce? Use Q = 0.0104 x A x i.

   • a.1.04 gpm
   • b.10.4 gpm
   • c.104 gpm
   • d.6.9 gpm

   Đáp án: b

   Giải thích: Q = 0.0104 x 1,000 x 1 = 10.4 gpm. This unit figure, 10.4 gpm per 1,000 ft^2 per inch of rain, lets you scale flow quickly for any roof and rate. Doubling either the area or the rate doubles the flow. IPC §1106.2.

   Nguồn: IPC §1106.2

5. 5. Design & Sizing

   Drinking fountains are required at 1 per 100 occupants. The occupant load is 350. What is the minimum number required?

   • a.4
   • b.3
   • c.2
   • d.5

   Đáp án: a

   Giải thích: 350 / 100 = 3.5, which rounds up to 4 drinking fountains. As with all fixture counts, a fractional result rounds up. Some codes allow bottle-filling stations to substitute for a portion of the fountains. IPC §410.1.

   Nguồn: IPC §410.1

6. 6. Systems & Code

   A vent terminal must be at least how far horizontally from an openable window or air intake (or extend above it)?

   • a.10 ft
   • b.2 ft, measured only from the roof surface below
   • c.5 ft from the wall but never from windows
   • d.No minimum distance if the vent is screened at the top

   Đáp án: a

   Giải thích: A vent terminal must be at least 10 ft horizontally from, or at least 3 ft above, any door, openable window, or air intake so sewer gas does not enter the building. Screening does not remove this separation requirement. The rule protects indoor air quality. IPC §903.5 / UPC §906.2.

   Nguồn: IPC §903.5 / UPC §906.2

7. 7. Systems & Code

   A sewage ejector discharge pipe requires which valves, in what order from the pump?

   • a.A gate valve only, with no check needed
   • b.A check valve, then a gate (shutoff) valve downstream
   • c.A single backwater valve mounted on the pump inlet side instead
   • d.Two check valves back to back for redundancy

   Đáp án: b

   Giải thích: The discharge has a check valve to stop effluent from draining back into the sump, followed by a gate valve so the check can be isolated for service. Without the check, each cycle refills the sump and short-cycles the pump. Order matters for servicing. IPC §712.3 / UPC §710.0.

   Nguồn: IPC §712.3 / UPC §710.0

8. 8. Gas & Fuel

   A single-wall metal vent connector runs from a gas appliance toward the chimney. What minimum clearance to combustibles is required?

   • a.6 in
   • b.0 in, since a metal connector may touch wood framing
   • c.1 in, which applies only to a listed double-wall connector
   • d.18 in, which is far more than the code requires here

   Đáp án: a

   Giải thích: A single-wall metal vent connector requires 6 in of clearance to combustibles, per IFGC 503.10.6, because its outer surface runs hot. Type B double-wall connectors allow reduced clearance (often 1 in) due to their air space. Reduced clearance requires a listed connector, not single-wall pipe.

   Nguồn: IFGC §503.10.6

9. 9. Administration

   A contract holds 10 percent retainage. On a $40,000 progress amount, how much is withheld?

   • a.$4,000
   • b.$400, off by a factor of ten in the percentage
   • c.$44,000, adding the retainage instead of subtracting it
   • d.$36,000, which is the amount released rather than withheld

   Đáp án: a

   Giải thích: Retainage = 10% x $40,000 = $4,000 withheld from the progress payment until the project is satisfactorily completed. Retainage protects the owner against defects and incomplete work and is released at final acceptance. The plumber receives the remaining $36,000 of that amount now.

   Nguồn: Contract law

10. 10. Safety

    How far back from a trench edge must excavated spoil and materials be kept?

    • a.Right at the edge is acceptable if the spoil pile is small
    • b.5 ft from the edge
    • c.At least 2 ft
    • d.1 ft from the edge

    Đáp án: c

    Giải thích: OSHA 1926.651 requires spoil piles, equipment, and materials to be set back at least 2 ft from the trench edge, or be retained, so their surcharge load does not collapse the wall or roll in on workers. On deeper or unstable trenches a greater setback may be needed. The competent person confirms it.

    Nguồn: 29 CFR 1926.651