DWV Code Quiz

Question 1

1. The minimum size floor drain for a residential installation is:
   a. 1-1/2”
   b. 2”
   c. 3”
   d. 4”

Answer 1

b. 2”

Question 2

2. Multiple shower heads may be served by a single trap, provided: (pick the answer that is incorrect):
   a. there are not more than 8 drains
   b. they are all in the same room
   c. they cannot receive food waste
   d. they are in a trench against the wall

Answer 2

a. there are not more than 8 drains

Question 3

3. What are the minimum test requirements for an underground sanitary building drain?
   a. an air pressure of 700 kpa for 2 hours
   b. a 3m head of water for 15 minutes
   c. 32mm of smoke fore 1 hour
   d. a visual inspection only

Answer 3

b. a 3m head of water for 15 minutes

Question 4

4. Prior to inspection, piping must be:
   a. tested
   b. approved by the AHJ
   c. checked by a supervisor
   d. removed and replaced when passed

Answer 4

a. tested

Question 5

5. Where is the clean out for a grease interceptor required to be placed?
   a. on the upstream piping
   b. on the vent
   c. on the downstream piping
   d. on the branch it drains to

Answer 5

c. on the downstream piping

Question 6

6. A sanitary building drain with 820 fixture units and a grade of 1/100 would have a diameter of”
   a. 6”
   b. 8”
   c. 10”
   d. 12”

Answer 6

b. 8”

Question 7

7. What is the minimum size of a combined building sewer with a load of 400 L and 270 fixture unites with a grade of 2%?
   a. 3”
   b. 4”
   c. 5”
   d. 6”

Answer 7

b. 4”

400 + (270 x 9.1) = 2766

Question 8

8. What is the minimum size of a floor drain that may be unvented?
   a. 2”
   b. 3”
   c. 4”
   d. 5”

Answer 8

b. 3”

Question 9

9. An 1-1/4”, a 1-1/2” and a 2” line all enter a sump within a building. What is the minimum size od a sump vent?
   a. not needed
   b. 1-1/4”
   c. 2”
   d. 3”

Answer 9

c. 2”

Question 10

10. What is the max length of a trap arm for a vented 3” floor drain?
    a. 2m
    b. 2.8m
    c. 3.6 m
    d. 4 m

Answer 10

c. 3.6 m

Question 11

11. In the diagram, where would be the best location for an additional circuit vent?
    a. A
    b. B
    c. C
    d. D

Answer 11

b. B

Question 12

12. An interceptor must be of sufficient capacity to:
    a. allow for grease to separate from the discharge
    b. allow turbulent flow through it
    c. allow the discharge to retain its heat
    d. not required cleaning for years

Answer 12

a. allow for grease to separate from the discharge

Question 13

13. When would a sand or grit interceptor be installed?
    a. always
    b. only when requested by the owner
    c. when required by the city or municipality
    d. never

Answer 13

c. when required by the city or municipality

Question 14

14. What is the purpose of the “flow control fitting” used with a grease interceptor?
    a. To speed up flow through the interceptor
    b. To slow down flow through the interceptor
    c. To increase flow through the piping downstream of the interceptor
    d. Slow down flow through the piping downstream of the interceptor

Answer 14

b. To slow down flow through the interceptor

Question 15

15. Piping that is too low to drain to a building drain is termed:
    a. subsoil drainage
    b. ponding drainage
    c. subdrainage
    d. subpar drainage

Answer 15

c. subdrainage

Question 16

16. A sewage sump, if inside a building, must have a(n):
    a. airtight cover
    b. warning sign
    c. guard around it
    d. perforated lid

Answer 16

a. airtight cover

Question 17

17. A sewage sump shall discharge into:
    a. a branch
    b. the building drain
    c. the building sewer
    d. a SOWS

Answer 17

b. the building drain

or

c. the building sewer

Question 18

18. The hydraulic load of a continuous-flow fixture, such as a pump, shall be:
    a. 31.7 FUs per gallon/minute
    b. 900 L per gallon/minute
    c. 900 gallon per L/second
    d. 31.7 FUs per L/second

Answer 18

d. 31.7 FUs per L/second

Question 19

19. The minimum size of floor drain for a residential installation is:
    a. 1-1/4”
    b. 1-1/2”
    c. 2”
    d. 3”

Answer 19

c. 2”

Question 20

20. When connecting a SOWS to a horizontal branch that serves a BRG upstream of the connection point, the proper fittings to use are:
    a. a TY and 1/8 bend
    b. a wye and 1/4 bend
    c. a wye and 1/8 bend
    d. a long-turn 1/4 bend

Answer 20

c. a wye and 1/8 bend

Question 21

21. What is the max size fixture drain that may connect to a wet vent?
    a. 1-1/4”
    b. 1-1/2”
    c. 2”
    d. 3”

Answer 21

c. 2”

Question 22

22. What is the minimum and max trap arm length of a 4” unvented floor drain?
    a. 2 times pipe diameter minimum and 4.8 m maximum
    b. 2 Times pipe diameter minimum and 9.6 m maximum
    c. 450 mm minimum and 4.8 m maximum
    d. 450 mm minimum at 9.8 m maximum

Answer 22

d. 450 mm minimum at 9.8 m maximum

Question 23

23. The correct size of a sump vent for a sump with a 4 inch branch draining to it is:
    a. 1-1/2”
    b. 2”
    c. 3”
    d. 4”

Answer 23

c. 3”

2” min, max 4”

Question 24

24. 1 L per second equals:
    a. 15.9 GPM
    b. 31.7 GPM
    c. 900 GPM
    d. 2360 GPM

Answer 24

a. 15.9 GPM

Question 25

25. 1 L per second equals: a. 9.1 FU b. 31.7 FU c. 900 FU d. 2360 FU

Answer 25

b. 31.7 FU

Question 26

26. 1 gallon per minute equals: a. 16 FU b. 9.1 FU c. 31.7 FU d. 900 FU

Answer 26

b. 1.9 FU

Question 27

27. When a building drain or branch could be subject to backflow: a. Normally closed back water valve is installed on either the branch or building dream b. Normally open back water valve is installed on either the branch or building drain c. a normally open back water valve is installed on the branch only d. Normally closed back water valve is installed on the building train only

Answer 27

b. Normally open back water valve is installed on either the branch or building drain

Question 28

28. A nominally-vertical pipe is one which is installed at an angle of: a. 45 degree with the vertical b. 45 degree with the horizontal c. more than 45 degrees with the horizontal d. all of the above

Answer 28

d. all of the above

Question 29

29. The max permitted length of a fixture outlet pipe is: a. 600 mm b. 750 mm c. 900 mm d. 1200 mm

Answer 29

d. 1200 mm

Question 30

30. Which of the following statements is true: a. all traps (other than WC) must have a cleanout at the lowest part or must be removable b. lavs, sinks, and laundry trays shall have clean-outs at the lowest part of the trap or it shall be removable c. drum traps may never be used d. bell traps are permitted in drainage systems if used in conjunction with an interceptor

Answer 30

b. lavs, sinks, and laundry trays shall have clean-outs at the lowest part of the trap or it shall be removable

Question 31

31. The minimum permissable grade on a 2" trap are is : a. 1/8" per foot (1 in 100) b. 1/4" per foot (1 in 50) c. one pipe diameter d. two pipe diameters

Answer 31

b. 1/4" per foot (1 in 50)

Question 32

32. The minimum permissible length of a 2" trap are is: a. 2" (50mm) b. 4" (100mm) c. 6" (150mm) d. there is no mimimum length

Answer 32

b. 4" (100mm) 2 x the pipe diameter for trap arms

Question 33

33. An 8" building drain with a max load of 1700 FU must be laid with a minimum grade per foot of: a. 1/16" (1 in 200) b. 1/8" (1 in 100) c. 1/4" (1 in 50) d. 1/2" (1 in 25)

Answer 33

c. 1/4" (1 in 50)

Question 34

34. The max number of FU that can drain into a 3" SOWS from one storey in a 5 storey building is: a. 18 b. 20 c. 30 d. 60

Answer 34

a. 18

Question 35

35. The minimum size of a stack vent required for a 4 inch soil or waste stock carrying 90 fixture units, when the length of a stack then is 10.68m is: a. 4" b. 3" c. 2-1/2" d. 2"

Answer 35

b. 3"

Question 36

36. The TY required for the connection of the 1-1/4" trap arm to the wet vent from a WC would be: a. 1-1/2" x 1-1/2" x 1-1/4" b. 2" x 1-1/4" x 1-1/2" c. 2" x 2"x 1-1/4" d. 2" x 1-1/2" x 1-1/4"

Answer 36

d. 2" x 1-1/2" x 1-1/4"

Question 37

37. The max cumulative change in direction on a trap arm serving a basin is: a. 45 degrees b. 90 degrees c. 135 degrees d. 225 degrees

Answer 37

c. 135 degrees

Question 38

38. Which of the following raps are not permitted? a. a trap with a trap seal of less than 100mm b. a bell trap c. a "P" trap d. a bell trap

Answer 38

d. a bell trap

Question 39

39. An oil interceptor requires: a. no vent pipes b. 1 vent pipe c. 2 vent pipes d. 3 vent pipes

Answer 39

c. 2 vent pipes

Question 40

40. Vent stacks are required when: a. a SOWS received the discharge from fixtures located on more than 4 stories b. a. a SOWS received the discharge from fixtures located on more than 5 stories c. a. a SOWS received the discharge from fixtures located on more than 10 stories d. a. a SOWS received the discharge from fixtures located on more than 11 stories

Answer 40

a. a SOWS received the discharge from fixtures located on more than 4 stories

Question 41

41. What is the max number of 90° bends which may be used on the trap arm of a water closet? a. 1 b. 2 c. 3 d. 90s may not be used

Answer 41

b. 2

Question 42

42. The downstream end of a P-trap seal may be connected to the trap arm by: a. a running thread b. a union with a gasket seal c. a slip joint d. a lock nut

Answer 42

c. a slip joint

Question 43

43. To prevent overflow in a sink that is not fitted with an integral or overflow, it is accepted to us a(n): a. standing waste b. float valve c. automatic siphon d. supply regulator

Answer 43

a. standing waste

Question 44

44. In which of the following locations would a slip joint not be permitted? a. anywhere on a venting system b. on the inlet to a trap c. to connect a trap to a tray d. on the fixture outlet of a 3-compartment sink

Answer 44

a. anywhere on a venting system

Question 45

45. When wet venting a water closet through a lav, the wet vented portion must be: a. 1-1/4" b. 1-1/2" c. 2" d. 3"

Answer 45

c. 2"

Question 46

46. What is the max length of a 1-1/4" continuous vent? a. 4 m b. 7 m c. 9 m d. no max

Answer 46

c. 9 m

Question 47

47. The max number of FU that can be carried by a 2" SOWS is: a. 6 b. 8 c. 18 d. 24

Answer 47

d. 24

Question 48

48. What is the max number of FU which may drain from any one floor in a 2" SOWS? a. 6 b. 8 c. 18 d. 24

Answer 48

a. 6

Question 49

49. The max number of WC that may drain to a 3" SOWS is: a. 2 b. 4 c. 6 d. 8

Answer 49

c. 6

Question 50

50. To size a vent other than an individual or dual vent, the follwoing info must be used: a. size of traps being served b. total FU c. length of pipe d. all of the above

Answer 50

d. all of the above