Self-Test 3.3 Storm Drainage Code Requirements

Complete Self-Test D-3.3 and check your answers.

  1. Using Figure 2P-46, fill in Table 1 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-46

 

Table 1
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
  1. Using Figure 2P-47, fill in Table 2 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-47

 

Table 2
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
  1. Using Figure 2P-48, fill in Table 3 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-48
Table 3
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
  1. Using Figure 2P-49, fill in Table 4 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-49
Table 4
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
  1. Using Figure 2P-50, fill in Table 5 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-50
Table 5
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
  1. Using Figure 2P-51, fill in Table 6 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-51
Table 6
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
  1. Using Figure 2P-52, fill in Table 7 by identifying and sizing the storm drainage installation as per the NPC.
Figure 2P-52
Table 7
Letter Name Leader (m2) Load Size
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
  1. What must be provided for when a roof drain is securely connected to a leader?
    1. Expansion
    2. Overflow
    3. Future loads
    4. Flow control

     

  2. What feature must be installed when a drinking fountain is subject to backflow and directly connected to a storm drainage system?
    1. Air gap
    2. Air break
    3. Backwater valve
    4. Stop lift

     

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

     

  4. What is the maximum spacing of riser clamp supports for a vertical three-storey rainwater leader?
    1. 6.5 m
    2. 7.0 m
    3. 7.5 m
    4. 8.0 m

     

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

     

  6. A drainage pipe that conducts both sewage and storm water is prohibited to be installed in what plane?
    1. Vertical
    2. Horizontal

     

  7. Which NPC table would be referred to when determining the maximum hydraulic load drained to a roof gutter?
    1. 2.4.10.6.C
    2. 2.4.10.9
    3. 2.4.10.10
    4. 2.4.10.11

     

  8. Does the NPC allow drainage pans serving heating and cooling units to drain to a storm drainage system?
    1. Yes
    2. No

     

  9. Does the NPC allow an overflow from a rainwater tank to be directly connected to a storm drainage system?
    1. Yes
    2. No

     

  10. If a leader receives semi or continuous flow from an appliance, what is the minimum size of trap required if the flow rate is 2.2 L/s?
    1. 2 in.
    2. 3 in.
    3. 4 in.
    4. 6 in.

     

  11. What is the minimum size of circular leader that receives a load of 30,000 L?
    1. 2 in.
    2. 3 in.
    3. 4 in.
    4. 6 in.

     

  12. Does the NPC allow a food display compartment to be directly connected to a storm drainage system?
    1. Yes
    2. No

     

  13. Does the NPC require a vent to protect a 2 in. floor drain connected to a storm drainage system?
    1. Yes
    2. No

     

  14. A 16 m by 18 m flat roof is served by a roof drain with three adjacent walls. The dimensions of the walls are: 16 m by 3 m, 18 m by 1 m, and 18 m by 1.5 m. What would be the load on the roof drain if the rainfall intensity was 7 mm/15 min?
    1. 2,016 L
    2. 2,184 L
    3. 2,205 L
    4. 2,352 L

     

  15. The RWL serving the roof drain in the previous question has an HVAC unit draining into it with a semi-continuous flow of 0.4 L/s. What load is to be considered at the base of the RWL?
    1. 2,360 L
    2. 2,544 L
    3. 3,360 L
    4. 4,376 L

     

  16. A combined building drain receives discharges of 477 FU, 1.3 L/s of continuous flow, and 3,200 L/15 min of storm drainage. What would be the load to consider when sizing the combined building drain?
    1. 2,360.5 L
    2. 6,730.8 L
    3. 7,810.4 L
    4. 8,710.7 L

     

  17. An outdoor restaurant patio is served by a storm drain that eventually connects to a combined building sewer. Does the storm drain require a trap?
    1. Yes
    2. No
    3. Not if the patio is on the roof
    4. Not if the storm drain is not subject to backflow

     

  18. You are installing a rainwater leader through a building. You have to offset the leader horizontally to accommodate a change in wall location. The offset you install measures 7.2 m. According to NPC requirements, what must the leader be sized as?
    1. Storm branch
    2. Leader but one size larger than it was prior to the offset
    3. Sanitary building drain
    4. Storm building drain

     

  19. You are asked to install flow-control roof drains on a flat roof that measures 90 m by 60 m. What is the minimum number of drains required for this installation?
    1. 2
    2. 4
    3. 6
    4. 8

     

  20. Referring to the above-mentioned installation, what would be the minimum number of overflow scuppers installed in conjunction with flow-control roof drains?
    1. 4
    2. 6
    3. 8
    4. 10

     

Answer Key: Self-Test D-3.3 is on the next page.

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Block D: Drainage Systems Copyright © 2025 by Skilled Trades BC, Thompson Rivers University is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book