Division B
Acceptable Solutions
Part 2 — Plumbing Systems
Section 2.4. Drainage Systems
2.4.1. Application
2.4.1.1. General

2.4.2. Connections to Drainage Systems
2.4.2.1. Connections to Sanitary Drainage Systems













2.4.2.2. Connection of Overflows from Rainwater Tanks
2.4.2.3. Direct Connections



2.4.3. Location of Fixtures
2.4.3.1. Urinals


2.4.3.2. Restricted Locations of Indirect Connections and Traps

2.4.3.3. Equipment Restrictions Upstream of Grease Interceptors

2.4.3.4. Fixtures Located in Chemical Storage Locations

2.4.3.5. Macerating Toilet Systems

2.4.3.6. Drains Serving Elevator Pits

2.4.4. Treatment of Sewage and Wastes
2.4.4.1. Sewage Treatment

2.4.4.2. Cooling of Hot Water or Sewage

2.4.4.3. Interceptors




2.4.4.4. Neutralizing and Dilution Tanks

2.4.5. Traps
2.4.5.1. Traps for Sanitary Drainage Systems






2.4.5.2. Traps for Storm Drainage Systems



2.4.5.3. Connection of Subsoil Drainage Pipe to a Sanitary Drainage System

2.4.5.4. Location and Cleanout for Building Traps

2.4.5.5. Trap Seals

2.4.6. Arrangement of Drainage Piping
2.4.6.1. Separate Systems

2.4.6.2. Location of Soil-or-Waste Pipes

2.4.6.3. Sumps or Tanks
(See Appendix A.)







2.4.6.4. Protection from Backflow






2.4.6.5. Mobile Home Sewer Service

2.4.7. Cleanouts
2.4.7.1. Cleanouts for Drainage Systems







2.4.7.2. Size and Spacing of Cleanouts

Table 2.4.7.2. Permitted Size and Spacing of Cleanouts Forming part of Sentence 2.4.7.2.(1) | |||
Size of Drainage Pipe, inches |
Maximum Spacing, m | ||
One-Way Rodding | Two-Way Rodding | ||
less than 3 |
Same size as drainage pipe |
7.5 | 15 |
3 and 4 |
Same size as drainage pipe |
15 | 30 |
over 4 | 4 | 26 | 52 |




2.4.7.3. Manholes



2.4.7.4. Location of Cleanouts




2.4.8. Minimum Slope and Length of Drainage Pipes
2.4.8.1. Minimum Slope

2.4.8.2. Length of Fixture Outlet Pipes

2.4.9. Size of Drainage Pipes
2.4.9.1. No Reduction in Size

2.4.9.2. Serving Water Closets



2.4.9.3. Size of Fixture Outlet Pipes


Table 2.4.9.3. Minimum Permitted Size of Fixture Outlet Pipe and Hydraulic Loads for Fixtures(1) Forming part of Sentences 2.4.9.3.(1) and 2.4.10.2.(1) | ||
Minimum Size of Fixture Outlet Pipe, inches |
Hydraulic Load, fixture units | |
Autopsy table | 1½ | 2 |
(a) with flush tank | n/a | 6 |
(b) with direct flush valve | n/a | 8 |
Bathtub (with or without shower) | 1½ | 1½ |
Bath: foot, sitz or slab | 1½ | 1½ |
Beer cabinet | 1½ | 1½ |
Bidet | 1¼ | 1 |
Clothes washer | ||
(a) domestic(1) | n/a |
|
(b) commercial | n/a |
2 with
|
Dental unit or cuspidor | 1¼ | 1 |
Dishwasher | ||
(a) domestic type | 1½ | 1½ no load when connected to garbage grinder or domestic sink |
(b) commercial type | 2 | 3 |
Drinking fountain | 1¼ | ½ |
Floor drain(2) |
2 |
2 with 2-in. trap |
3 with 3-in. trap |
||
Garbage grinder, commercial type | 2 | 3 |
Icebox | 1¼ | 1 |
Laundry tray | ||
(a) single or double units or 2 single units with common trap | 1½ | 1½ |
(b) 3 compartments | 1½ | 2 |
Lavatory | ||
(a) barber or beauty parlor | 1½ | 1½ |
(b) dental | 1¼ | 1 |
(c) domestic type, single or | 1¼ |
1 with 1¼-in. trap |
2 single with common trap |
1½ with 1½-in. trap |
|
(d) multiple or industrial type | 1½ |
according to Table 2.4.10.2. |
|
|
|
Potato peeler | 2 | 3 |
Shower drain | ||
(a) from 1 head | 1½ | 1½ |
(b) from 2 or 3 heads | 2 | 3 |
(c) from 4 to 6 heads | 3 | 6 |
Sink | ||
(a) domestic and other small types with or without garbage grinders, single, double or 2 single with a common trap | 1½ | 1½ |
(b) Other sinks | 1½ |
1½ with 1½-in. trap |
2 with 2-in. trap |
||
3 with 3-in. trap |
||
Urinal | ||
(a) pedestal, siphon-jet or blowout type | 2 | 4 |
(b) stall, washout type | 2 | 2 |
(c) wall | ||
(i) washout type | 1½ | 1½ |
(ii) other types | 2 | 3 |
Water closet | ||
(a) with flush tank | 3 | 4 |
(b) with direct flush valve | 3 | 6 |
Notes to Table 2.4.9.3.: | |
|
|
(1) | See Appendix A. |
(2) | No hydraulic load for emergency floor drains. |

2.4.9.4. Size of Building Drain and Building Sewer

2.4.9.5. Offset in Leaders

2.4.10. Hydraulic Loads
(See Appendix A for determination of hydraulic loads and drainage pipe sizes.)2.4.10.1. Total Load on a Pipe

2.4.10.2. Hydraulic Loads for Fixtures


Table 2.4.10.2. Permitted Hydraulic Load from a Fixture Based on Size of Trap Forming part of Sentence 2.4.10.2.(2) | |
Hydraulic Load, fixture units | |
1¼ | 1 |
1½ | 2 |
2 | 3 |
2½ | 4 |
3 | 5 |
4 | 6 |
2.4.10.3. Hydraulic Loads from Fixtures with a Continuous Flow


2.4.10.4. Hydraulic Loads from Roofs or Paved Surfaces













2.4.10.5. Conversion of Fixture Units to Litres

2.4.10.6. Hydraulic Loads to Soil-or-Waste Pipes


Table 2.4.10.6.A Maximum Permitted Hydraulic Load Drained to a Soil-or-Waste Stack Forming part of Sentence 2.4.10.6.(1) | ||
Size of Stack, inches |
Maximum Hydraulic Load, fixture units |
Maximum Fixture Units Drained from any 1 Storey |
1¼ | 2 | 2 |
1½ | 8 | 2 |
2 | 24 | 6 |
3 | 102 | 18 |
4 | 540 | 100 |
5 | 1 400 | 250 |
6 | 2 900 | 500 |
8 | 7 600 | 830 |
10 | 15 000 | 2 700 |
12 | 26 000 | 4 680 |
15 | 50 000 | 9 000 |
Table 2.4.10.6.B Maximum Permitted Hydraulic Load Drained to a Branch Forming part of Sentence 2.4.10.6.(2) and Article 2.4.10.7. | |
Maximum Hydraulic Load, fixture units | |
1¼ | 2 |
1½ | 3 |
2 | 6 |
2½ | 12 |
3 | 27 |
4 | 180 |
5 | 390 |
6 | 700 |
8 | 1 600 |
10 | 2 500 |
12 | 3 900 |
Table 2.4.10.6.C Maximum Permitted Hydraulic Load Drained to a Sanitary Building Drain or Sewer Forming part of Sentence 2.4.10.6.(2) and Article 2.4.10.8. | ||||||
Size of Drain or Sewer, inches |
Maximum Hydraulic Load, fixture units |
|||||
Slope | ||||||
1 in 400 | 1 in 200 | 1 in 133 | 1 in 100 | 1 in 50 | 1 in 25 | |
3 | — | — | — | — | 27 | 36 |
4 | — | — | — | 180 | 240 | 300 |
5 | — | — | 380 | 390 | 480 | 670 |
6 | — | — | 600 | 700 | 840 | 1 300 |
8 | — | 1 400 | 1 500 | 1 600 | 2 250 | 3 370 |
10 | — | 2 500 | 2 700 | 3 000 | 4 500 | 6 500 |
12 | 2 240 | 3 900 | 4 500 | 5 400 | 8 300 | 13 000 |
15 | 4 800 | 7 000 | 9 300 | 10 400 | 16 300 | 22 500 |
2.4.10.7. Hydraulic Loads on Branches
2.4.10.8. Hydraulic Loads on Sanitary Building Drains or Sewers

2.4.10.9. Hydraulic Loads on Storm or Combined Building Drains or Sewers

Table 2.4.10.9. Maximum Permitted Hydraulic Load Drained to a Storm Building Drain or Sewer or a Combined Building Sewer Forming part of Article 2.4.10.9. | |||||||
Size of Drain or Sewer, inches |
Maximum Hydraulic Load, L | ||||||
Slope | |||||||
1 in 400 | 1 in 200 | 1 in 133 | 1 in 100 | 1 in 68 | 1 in 50 | 1 in 25 | |
3 | — | — | — | — | ![]() ![]() | 2 770 | 3 910 |
4 | — | — | — | 4 220 | 5 160 | 5 970 | 8 430 |
5 | — | — | 6 760 | 7 650 | 9 350 | 10 800 | 15 300 |
6 | — | — | 10 700 | 12 400 | 15 200 | 17 600 | 24 900 |
8 | — | 18 900 | 23 200 | 26 700 | 32 800 | 37 800 | 53 600 |
10 | — | 34 300 | 41 900 | 48 500 | 59 400 | 68 600 | 97 000 |
12 | 37 400 | 55 900 | 68 300 | 78 700 | 96 500 | 112 000 | 158 000 |
15 | 71 400 | 101 000 | 124 000 | 143 000 | 175 000 | 202 000 | 287 000 |
2.4.10.10. Hydraulic Loads to Roof Gutters
Table 2.4.10.10. Maximum Permitted Hydraulic Load Drained to a Roof Gutter Forming part of Article 2.4.10.10. | |||||
Size of Gutter, inches |
Area of Gutter, cm2 |
Maximum Hydraulic Load, L | |||
Slope | |||||
1 in 200 | 1 in 100 | 1 in 50 | 1 in 25 | ||
3 | 22.8 | 406 | 559 | 812 | 1 140 |
4 | 40.5 | 838 | 1 190 | 1 700 | 2 410 |
5 | 63.3 | 1 470 | 2 080 | 2 950 | 4 170 |
6 | 91.2 | 2 260 | 3 200 | 4 520 | 6 530 |
7 | 124.1 | 3 250 | 4 600 | 6 500 | 9 190 |
8 | 162.1 | 4 700 | 6 600 | 9 400 | 13 200 |
10 | 253.4 | 8 480 | 12 000 | 17 000 | 23 600 |
2.4.10.11. Hydraulic Loads on Leaders
Table 2.4.10.11. Maximum Permitted Hydraulic Load Drained to a Leader Forming part of Article 2.4.10.11. | |||
Circular Leader |
Non-Circular Leader | ||
Maximum Hydraulic Load, L |
Area of Leader, cm2 | Maximum Hydraulic Load, L | |
2 | 1 700 | 20.3 | 1 520 |
2½ | 3 070 | 31.6 | 2 770 |
3 | 5 000 | 45.6 | 4 500 |
4 | 10 800 | 81.1 | 9 700 |
5 | 19 500 | 126.6 | 17 600 |
6 | 31 800 | 182.4 | 28 700 |
8 | 68 300 | 324.3 | 61 500 |
2.4.10.12. Hydraulic Loads from Fixtures with a Semi-continuous Flow

Table 2.4.10.12. Maximum Permitted Hydraulic Load from Fixtures with a Semi-continuous Flow Forming part of Sentence 2.4.10.12.(1) | ||
Flow, L/s |
Hydraulic Load, fixture units | |
1½ | 0.00 - 0.090 | 3 |
2 | 0.091 - 0.190 | 6 |
3 | 0.191 - 0.850 | 27 |
4 | 0.851 - 5.700 | 180 |
2.4.10.13. Design of Storm Sewers
