Journeyman 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. Drainage, Waste & Vent

   A horizontal 2 in fixture branch is installed at the code minimum slope. Over a developed run of 18 ft, how much total fall does the pipe have?

   • a.9 in
   • b.2-1/4 in
   • c.1-1/8 in
   • d.4-1/2 in

   Đáp án: d

   Giải thích: Pipe 2-1/2 in and smaller requires a minimum slope of 1/4 in per ft, so 18 ft x 1/4 in = 4-1/2 in of fall. 1-1/8 in comes from using 1/16 in per ft and 2-1/4 in from using the 1/8 in per ft rate that applies only to 3 in and larger pipe. 9 in would be 1/2 in per ft, which is double the required minimum.

   Nguồn: IPC §704.1

2. 2. Drainage, Waste & Vent

   A row of five lavatories on a common horizontal branch in a public restroom is vented by a single vent connected between the last two fixture drains. What type of venting is this?

   • a.Common vent
   • b.Individual vent
   • c.Island vent
   • d.Circuit vent

   Đáp án: d

   Giải thích: A circuit vent serves a battery of fixtures on a horizontal branch with one vent taken off ahead of the last fixture connection. A common vent serves only two fixtures connecting at the same level, an island vent is a loop arrangement for a fixture with no wall, and an individual vent serves one fixture drain.

3. 3. Water Supply & Distribution

   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

   Đáp án: a

   Giải thích: 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.

   Nguồn: IPC §605

4. 4. Gas Piping

   A gas furnace sits in a basement mechanical room. Its manual shutoff valve is installed in an adjacent storage room 9 ft away, behind a closed door. Why does this installation fail inspection?

   • a.Only the single main shutoff valve located out at the gas meter is permitted to serve a furnace
   • b.The valve must be downstream of the appliance regulator
   • c.The shutoff must be within 6 ft of the appliance and in the same room as the appliance
   • d.Shutoff valves must be within 3 ft of the appliance

   Đáp án: c

   Giải thích: Each appliance needs an accessible manual shutoff valve located in the same room as the appliance and within 6 ft of it, so a valve 9 ft away in another room is not acceptable. The 3 ft figure is a connector length limit, not a valve distance; a main valve at the meter does not satisfy the individual appliance shutoff; and the appliance shutoff belongs upstream of the appliance controls.

   Nguồn: IFGC §409.5

5. 5. Codes & Safety

   While replacing a section of galvanized water piping in a building from the 1950s, a plumber finds an adjacent steam line wrapped in crumbling fibrous insulation and sees that the old water joints were made with 50/50 tin-lead solder. What is the correct response?

   • a.Disturb the crumbling insulation only while wearing an ordinary filtering facepiece dust mask, and reuse the old 50/50 tin-lead solder on the new joints so that they match the rest of the existing system throughout the building
   • b.Leave the suspect asbestos insulation undisturbed, stop work in that area and notify the employer or building owner so a licensed abatement contractor can assess it, and make the new joints with lead-free solder
   • c.Cut the insulation off with a utility knife, bag it, and continue with the repair
   • d.Wet the insulation before removing it, since wetting eliminates the need for a licensed abatement contractor

   Đáp án: b

   Giải thích: Deteriorating pipe insulation in a building of that era is presumed asbestos-containing until sampling proves otherwise, and the correct action is to leave it alone, keep others out of the area and report it so licensed abatement personnel handle the removal. Cutting, scraping or wetting it yourself still releases fibers and does not make an untrained worker an abatement contractor, and a filtering facepiece does not authorize the work either. On the piping side, 50/50 tin-lead solder is prohibited in potable water systems; solder and flux must be lead free, and wetted surfaces of pipe, fittings and fixtures must not exceed a weighted average lead content of 0.25 percent.

6. 6. Codes & Safety

   Nonpotable reclaimed (recycled) water distribution piping must be identified how, to prevent a cross-connection with the potable supply?

   • a.Left unmarked, since it runs on a completely separate pressure zone
   • b.Colored purple and marked nonpotable, with no tie to the potable system
   • c.Colored the same blue as the potable cold-water distribution piping
   • d.Identified only by a wrap of green tape located at the meter

   Đáp án: b

   Giải thích: Reclaimed-water piping is colored purple and marked as nonpotable so no one mistakes it for drinking water and cross-connects it to the potable system, which must stay physically separate. Leaving it unmarked, coloring it blue like the cold-water line, or taping only the meter would all invite a dangerous cross-connection.

   Nguồn: IPC §1301 / UPC §1602

7. 7. Drainage, Waste & Vent

   A sewage ejector receives the discharge of a water closet. What is the minimum size of its discharge pipe?

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

   Đáp án: d

   Giải thích: A sewage ejector or pump receiving water-closet discharge must have a discharge pipe of at least 2 in so it can pass solids (IPC 712.3.2). 1-1/4 in and 1-1/2 in are undersized for sewage, and 3 in is larger than the minimum required.

8. 8. Water Supply & Distribution

   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

   Đáp án: d

   Giải thích: 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.

9. 9. Fixtures & Water Heaters

   A hydromechanical (point-of-use) grease interceptor requires what on its inlet side?

   • a.A food grinder discharging into it
   • b.A flow-control fitting with an air (vent) intake ahead of it
   • c.A connection downstream of a water closet
   • d.No flow control

   Đáp án: b

   Giải thích: A hydromechanical grease interceptor must have a flow-control fitting with an air intake so influent is limited to the rated flow and grease can separate (IPC 1003.3.1). A disposer or water-closet waste is prohibited from a grease interceptor.

10. 10. Gas Piping

    What is the approximate heating value of propane vapor?

    • a.About 1,000 Btu per cubic foot
    • b.About 500 Btu per cubic foot
    • c.About 2,500 Btu per cubic foot
    • d.About 91,500 Btu per cubic foot

    Đáp án: c

    Giải thích: Propane vapor carries about 2,500 Btu per cubic foot, roughly two and a half times natural gas at about 1,000 Btu per cubic foot. The 91,500 figure is the energy per gallon of liquid propane, not per cubic foot of vapor.