Self-Test D-1.10 Requirements and Prohibitions for DWV Systems

Complete Self-Test D-1.10 and check your answers.

1. Piping, fittings and joints used in a pressure sewer, forcemain, or sump pump discharge applications shall be capable of withstanding at least ______ times the potential pressure.
   1. 1.5
   2. 2
   3. 2.5
   4. 3

    

2. What is the maximum number of showerheads that can be served by a single shower drain?
   1. 3
   2. 4
   3. 5
   4. 6

    

3. Except for column showers, what is the minimum dimension between two adjacent showerheads?
   1. 730 mm
   2. 690 mm
   3. 750 mm
   4. 800 mm

    

4. What type of fixture shall not have a concealed overflow?
   1. Lavatory
   2. Shampoo sink
   3. Food prep sink
   4. Shower

    

5. Where must copper tube not be used when connecting a flush valve–operated urinal?
   1. Branch drain serving the fixture
   2. Vent above the flood level rim
   3. Fixture drain
   4. Both b and c

    

6. What type of material may the cleanout plug be made of if serving a 2 in. trap standard made of cast-iron?
   1. Cast iron
   2. Galvanized steel
   3. Brass
   4. Both b and c

    

7. What is the minimum trap seal depth for a lab sink that drains to an acid waste system?
   1. 25 mm
   2. 33 mm
   3. 38 mm
   4. 50 mm

    

8. According to the NPC, which of the following types of traps are prohibited?
   1. Bell traps
   2. Crown-vented trap
   3. All of the above

    

9. Transition solvent cement permitted by the NPC is used to join which type of pipe?
   1. ABS drainage to PE subsoil drainage
   2. PVC pressure to CPVC pressure
   3. PVC drainage to PE subsoil drainage
   4. PVC drainage to ABS drainage

    

10. Fasteners used to secure WC flanges to a building structure must have what quality?
    1. Corrosion resistant
    2. Coarse thread
    3. Expansion type
    4. Non-removable

     

11. If an indirectly connected 1.5 in. pipe forms an air break above a directly connected fixture, what is the minimum dimension of the air break?
    1. 1.25 in.
    2. 1.5 in.
    3. 2 in.
    4. 3 in.

     

12. What is the maximum pipe support spacing for a vertical three-storey stack?
    1. 6.5 m
    2. 7.0 m
    3. 7.5 m
    4. 8.0 m

     

13. When installing a hub and spigot pipe, at which end of the pipe shall the hub be installed?
    1. Upstream
    2. Downstream

     

14. What is the minimum depth of lead in a cold-caulked lead drainage joint?
    1. 15 mm
    2. 25 mm
    3. 50 mm
    4. 75 mm

     

15. When installing a caulked lead drainage joint, when is it acceptable to paint the pipe and caulking material?
    1. Immediately after installation
    2. Before testing the joint
    3. After testing the joint
    4. Never paint a lead joint; it will turn toxic.

     

16. What is the maximum hanger spacing for horizontal cast-iron soil pipe?
    1. 1 m
    2. 2 m
    3. 3 m
    4. 4 m

     

17. What is the maximum hanger spacing for horizontal PVC pipe?
    1. 1 m
    2. 1.2 m
    3. 1.3 m
    4. 1.4 m

     

18. When installing copper tube underground, the joints shall be joined by what method?
    1. Soldered or compression
    2. Soldered or brazed
    3. Brazed or screwed
    4. Brazed or flared

     

19. Cold-caulked joints shall only be used in which of the following bell and spigot piping systems?
    1. Water systems
    2. Drainage systems
    3. Venting systems
    4. Any of the above

     

20. When installing a lead stub during the rough-in of a WC, what type of floor flange shall be used when the toilet is set in place?
    1. ABS
    2. Cast-iron
    3. Lead
    4. Brass

     

21. Which fixture does not have to be directly connected to a sanitary drainage system?
    1. Kitchen sink
    2. Toilet c/w flush valve
    3. Drinking fountain
    4. Bar sink

     

22. What is the maximum permitted hydraulic load drained to a 12 in. sanitary building drain with a slope of 1:200?
    1. 1,400 FU
    2. 2,500 FU
    3. 3,900 FU
    4. 4,500 FU

     

23. You are sent to an existing house to rough-in a basement bathroom group. The building drain that you want to tie into serves a stack with 35 FU draining to it. What is the minimum distance from the base of the stack to the tie-in point that must be maintained in this situation?
    1. 1 m
    2. 1.5 m
    3. 2 m
    4. No restriction

     

24. You are sent to a business that provides bottled water for its customers. You are to provide a drainage system for six reverse osmosis (RO) water filtration units. You have decided to connect the drains to a common branch and then indirectly connect the branch to the sanitary drainage system. What is the minimum size of the common branch in this situation?
    1. 0.75 in.
    2. 1 in.
    3. 1.25 in.
    4. Twice the size of the largest drain (air gap)

     

25. Urinals shall not be installed in which of the following areas?
    1. Residential occupancy buildings
    2. Where the wall and floor surfaces are pervious to water
    3. Where there is no emergency floor drain
    4. All of the above

     

26. You are installing a domestic dishwasher and are going to drain the machine to the fixture outlet pipe of an adjacent kitchen sink. What type of fitting would you use to make the connection at the fixture outlet pipe?
    1. Sanitary tee
    2. Sanitary tee and a 90° ell
    3. Wye fitting
    4. Any of the above

     

27. A cleanout fitting serving a building trap shall be installed in which location(s) listed below?
    1. Directly over the upstream side of the trap
    2. Directly over the downstream side of the trap
    3. As close as practicable to where the building drain leaves the building
    4. Any of the above

     

28. When a building trap is installed, where does the NPC allow it to be located?
    1. Upstream of the main building cleanout
    2. Outside the building in a manhole
    3. Inside the building as close as practicable to where the building drain leaves the building
    4. Any of the above

     

29. Is the drain from an indirectly connected drinking fountain considered an acceptable method of maintaining the trap seal for a floor drain?
    1. Yes
    2. No
    3. Yes, but only if the floor drain drains to a storm drainage system
    4. No, only a manufactured trap seal primer is acceptable for this situation

     

30. There are certain requirements for the order in which valves and fittings are installed on a sump pump discharge. Listing the items in the direction of flow, what is the proper order?
    1. Union, shut-off valve, check valve
    2. Shut off-valve, union, check valve
    3. Union, check valve, shut-off valve
    4. Check valve, union, shut-off valve

     

31. When installed in a single-family dwelling building drain, a backwater valve shall meet which of the following requirements?
    1. Normally closed
    2. Normally open
    3. Larger than 4 in. NPS
    4. Not allowed by code on a building drain or building sewer

     

32. A floor drain subject to backflow may be protected in which manner?
    1. Backwater valve only
    2. Backwater valve or gate valve only
    3. Backwater valve, gate valve, or removable screw cap on the upstream side of the trap
    4. A floor drain subject to backflow cannot be installed.

     

33. A building sewer that serves a mobile home shall meet which of the following requirements?
    1. Minimum 4 in. NPS in size
    2. Terminated below ground in a frost-free vault
    3. Be of flexible construction to accommodate connection
    4. All of the above

     

34. What is the minimum size of cleanout fittings installed for pipes with diameters of 4 in. or less?
    1. Half the size of the drainage pipe being served
    2. The size of the drainage pipe being served
    3. The same size of the drainage pipe being served
    4. 4 in.

     

35. When installing a cleanout for a 4 in. building sewer using a wye fitting 6 ft below grade, what is the maximum length of pipe you can install before the next cleanout is required?
    1. 7.5 m
    2. 15 m
    3. 26 m
    4. 30 m

     

36. Every building drain shall be provided with a cleanout fitting located at which of the following locations?
    1. Upstream of the building trap
    2. At the base of the stack
    3. As close as practicable to where the building drain leaves the building
    4. Any of the above

     

37. When a manhole more than 1 m in depth is located in a building, which of the following features must it be provided with?
    1. Vent
    2. Corrosion-resistant ladder
    3. Cover with an airtight seal
    4. All of the above

     

38. What is the minimum horizontal dimension of a manhole at the bottom of the enclosure?
    1. 500 mm
    2. 600 mm
    3. 1,000 mm
    4. 1,500 mm

     

39. What is the minimum horizontal dimension of a manhole at the top of the enclosure?
    1. 500 mm
    2. 600 mm
    3. 1,000 mm
    4. 1,500 mm

     

40. When roughing in an autopsy table at your neighbourhood mortuary, what is the minimum dimension above the flood level rim of the autopsy table that the cleanout could be installed?
    1. 150 mm
    2. 200 mm
    3. 300 mm
    4. 350 mm

     

41. When installing a grease interceptor to serve as a fixture trap for a commercial kitchen sink, what is the maximum developed length of the fixture outlet pipe between the sink and the interceptor?
    1. 900 mm
    2. 1 m
    3. 1.2 m
    4. 1.5 m

     

42. You are installing a triple-compartment kitchen sink equipped with 1.5 in. tailpieces. You are told to drain all compartments to a common trap. What is the minimum size trap that will suit this installation?
    1. 1.5 in.
    2. 2 in.
    3. 3 in.
    4. 4 in.

     

43. When installing a washer box in a single-family dwelling laundry room, what is the minimum distance of the drain standpipe measured from the trap weir to the top of the standpipe?
    1. 400 mm
    2. 600 mm
    3. 800 mm
    4. 1 m

     

44. When installing a washer box in a single-family dwelling laundry room, at what height above the floor shall the drain opening of the box be?
    1. Below the flood level rim of the washing machine
    2. Level with the flood level rim of the washing machine
    3. Above the flood level rim of the washing machine
    4. Any of the above

     

45. You are installing a stack through a building. You have to offset the stack 2 m horizontally to accommodate a change in wall location. The offset and lower section of stack shall be sized as which of the following?
    1. Sanitary branch
    2. Stack, but one size larger than it was prior to the offset
    3. Sanitary building drain
    4. Either a or c, whichever is less restrictive

     

46. What is the minimum size of a vent pipe that serves a manhole within a building?
    1. 1.5 in.
    2. 2 in.
    3. 3 in.
    4. 4 in.

     

47. What is the maximum length of a 3 in. wet vent?
    1. 1.5 m
    2. 2 m
    3. 3 m
    4. There is no limit to the length of a wet vent.

     

48. What is the minimum size of a vent pipe that serves a sewage sump?
    1. 1.25 in.
    2. 1.5 in.
    3. 2 in.
    4. 3 in.

     

49. What is the maximum change in direction that a basin trap arm may have before it is vented?
    1. 115°
    2. 125°
    3. 135°
    4. 225°

     

50. What is the minimum distance that a stack vent can terminate from an openable window or other air inlet?
    1. 3.0 m
    2. 3.5 m
    3. 4.0 m
    4. 4.5 m

     

51. If a sewage sump has a 6 in. pipe draining into it, what is the minimum size vent for the sump?
    1. 3 in.
    2. 4 in.
    3. 5 in.
    4. 6 in.

     

52. What is the minimum difference in elevation between the two vents serving an oil interceptor?
    1. 150 mm
    2. 200 mm
    3. 250 mm
    4. 300 mm

     

53. What is the minimum distance that a vent must terminate above the roof?
    1. 25 mm
    2. 50 mm
    3. 100 mm
    4. 150 mm

     

54. What is the maximum change in direction that a water closet trap arm may have before it is vented?
    1. 115°
    2. 125°
    3. 135°
    4. 225°

     

55. With regard to a multi-storey wet vent, what is the maximum load drained to the wet vent from any one storey above the first storey when the stack passes through more than one storey?
    1. 4
    2. 8
    3. 16
    4. No limit

     

56. What is the maximum number of fixture units that can be drained to the base of a vent stack?
    1. 6
    2. 8
    3. No drainage can discharge on a vent stack.
    4. No limit

     

57. A stack that serves as a multi-storey wet vent has restrictions regarding offsets. Choose the clause that best describes these restrictions for a wet-vented stack.
    1. Cannot have offsets
    2. May have one offset that does not exceed 2 m in length
    3. May have two offsets that do not exceed 2.5 m in length
    4. May have one offset that does not exceed 2.5 m in length

     

58. A wet-vented stack has fixtures draining into it from six storeys. The stack is serving two water closets located on the bottom floor. There are two kitchen sinks on each of the five floors above the bottom floor. What is the minimum size of the stack vent if it is 20 m in length?
    1. 3 in.
    2. 4 in.
    3. 5 in.
    4. 6 in.

     

59. What is the minimum size of a fresh air inlet?
    1. 1.5 in.
    2. 2 in.
    3. 4 in.
    4. 3 in.

     

60. Which of the following must a relief vent serving a circuit-vented branch be?
    1. A sanitary drainage pipe with at least 6 FU draining to it
    2. Connected downstream of the most downstream water closet
    3. Connected to the trap arm of the most upstream fixture
    4. Connected downstream of the most downstream circuit-vented fixture

     

61. A 12-storey building served by a 3 in. stack and a 2 in. vent stack may require a yoke vent. What would be the minimum size of the yoke vent in this situation?
    1. 1.5 in.
    2. 2 in.
    3. 3 in.
    4. 4 in.

     

62. A stack in a building has a nominally horizontal, 2-m long offset installed in it. The load above the offset is 143 FU draining from three floors. What is the additional venting requirement for this situation?
    1. No additional venting required
    2. One relief vent for the offset
    3. Two relief vents for the offset
    4. Three relief vents for the offset

     

63. If a combined relief vent is serving two circuit-vented branches, the combined relief vent must conform to which of the following requirements?
    1. 2 in. minimum size
    2. Sized as a wet vent
    3. Symmetrically connected
    4. Same size as the largest circuit vent

     

64. If an additional circuit vent is installed in conjunction with a circuit-vented branch and has a lavatory draining to it, the portion of the additional circuit vent that accepts the drainage shall conform to which of the following requirements?
    1. Same size as the circuit vent
    2. One size smaller than the circuit vent
    3. Sized as a wet vent, maximum 2 in.
    4. Sized as a wet vent, minimum 2 in.

     

65. If you are hired to install an acid dilution tank at a hospital lab, does the NPC allow you to connect the dilution tank vent to the existing plumbing venting system?
    1. Yes, if the existing venting is cast iron
    2. Yes, to a vent stack only, not to a branch vent
    3. No, use an island vent configuration
    4. No, it must be independent to open air

     

66. Which of the following fixtures would be considered when determining the hydraulic load on a continuous vent that serves a wet-vented branch?
    1. All fixtures draining to the wet vent, including the water closets
    2. All fixtures except 2 in. emergency floor drains
    3. All wet-vented fixtures, except the water closets
    4. All wet-vented fixtures

     

67. When circuit venting three drinking fountains, what would be the size of the fixture drain immediately downstream of the circuit vent connection?
    1. 1.25 in.
    2. 1.5 in.
    3. 2 in.
    4. 3 in.

     

68. When circuit venting four 2 in. showers, what would be the size of the fixture drain immediately downstream of the circuit vent connection?
    1. 2 in.
    2. 2.5 in.
    3. 3 in.
    4. 4 in.

     

69. What is the hydraulic load to be considered when sizing a circuit vent that serves a circuit-vented branch?
    1. All fixtures draining to the circuit-vented branch
    2. All fixtures draining to the circuit-vented branch, except separately vented fixtures
    3. All circuit-vented fixtures and the fixtures attached to the relief vent
    4. All circuit-vented fixtures

     

70. When circuit venting four drinking fountains, what is the size of the fixture drain immediately upstream of the circuit vent connection?
    1. 1.25 in.
    2. 1.5 in.
    3. 2 in.
    4. 3 in.

     

71. What is the code restriction for connecting fixtures to a circuit vent or an additional circuit vent?
    1. 1 fixture maximum; 2 in. trap size
    2. 2 fixtures maximum; 2 FU each
    3. 1 fixture maximum; 1.5 in. trap size
    4. 2 fixtures maximum; 1.5 FU each

     

72. What are the venting requirements for a secondary receiver installed in conjunction with an oil interceptor?
    1. 1.5 in. minimum size
    2. 2 in. minimum size
    3. 1 size smaller than the largest inlet
    4. It does not require a vent.

     

73. You have been hired to install the rough DVW piping in a single-family dwelling. You decide to stub a future vent into the basement. Due to no sewage sump in the basement, what would be the minimum size vent allowed by code?
    1. 1.25 in.
    2. 1.5 in.
    3. 2 in.
    4. 3 in.

     

74. What is the maximum horizontal distance a 3 in. trap arm serving a water closet may run before a vent connection is provided?
    1. 1.2 m
    2. 1.5 m
    3. 3 m
    4. 3.6 m

     

75. In areas where vents are subject to frost closure, the code allows for the installation of air admittance valves. Could all of the vents serving a single-family dwelling be air admittance valves?
    1. Yes, without any code restrictions
    2. No
    3. Yes, a maximum of four valves that must terminate where they will not freeze
    4. Yes, only if all the fixtures are individually vented and the valves terminate in an area where they will not freeze

     

76. When terminating an air admittance valve in an area where insulation materials are present, what is the minimum distance above the insulation that the valve can be installed?
    1. 100 mm
    2. 150 mm
    3. Cannot be installed in areas where insulation materials are present
    4. Should be covered by insulation so it will not freeze shut

     

77. You are installing an island vented kitchen sink. You decide to use an air admittance valve for your vent. What is the minimum distance above the trap arm of the sink that the valve may be installed?
    1. 100 mm
    2. 150 mm
    3. Above the flood level rim of the sink
    4. No minimum distance above the trap arm

     

Answer Key: Self-Test D-1.10 is on the next page.