Division B
Acceptable Solutions

Part 7 — Plumbing Systems

Section 7.4. Drainage Systems

7.4.1. Application

7.4.1.1. General

1) This Section applies to sanitary drainage systems, storm drainage systems, combined building drains or combined building sewers.I

7.4.2. Connections to Drainage Systems

7.4.2.1. Connections to Sanitary Drainage Systems

1) Every fixture shall be directly connected to a sanitary drainage system, except thatI

a)drinking fountains may be

i)indirectly connected to a sanitary drainage system, or

ii)connected to a storm drainage system provided that where the system is subject to backflow, a backwater valve is installed in the fountain waste pipe (See Appendix A),

b)drainage pans on heating/cooling units may be connected to a storm drainage system provided that where the system is subject to backflow, a backwater valve is installed,

c)a floor drain may be connected to a storm drainage system provided it is located where it can receive only clear-water waste or storm water,

d)fixtures or appliances that discharge only clear-water waste may be connected to a storm drainage system or be drained onto a roof, and

e)the following devices shall be indirectly connected to a drainage system:

i)a device for the display, storage, preparation or processing of food or drink,

ii)a sterilizer,

iii)a device that uses water as a cooling or heating medium,

iv)a water operated device,

v)a water treatment device, or

vi)a drain or overflow from a water system or a heating system (see Appendix A).

2) The connection of a soil-or-waste pipe to a nominally horizontal soil-or-waste pipe or to a nominally horizontal offset in a soil-or-waste stack shall be not less than 1.5 m measured horizontally from the bottom of a soil-or-waste stack or from the bottom of the upper vertical section of the soil-or-waste stack thatI

a)receives a discharge of 30 or more fixture units, or

b)receives a discharge from fixtures located on 2 or more storeys.

(See Appendix A.)

3) No other fixture shall be connected to a lead bend or stub that serves a water closet.I

4) A soil-or-waste pipe that serves more than one clothes washer, and in which pressure zones are created by detergent suds, shall not serve for connecting other soil-or-waste pipes. (See Appendix A.)I

5) All floor and hub drains located in food display areas shall be connected to a trade waste system and shall be protected from backflow from the sanitary drainage system. [See Appendix A.]I

6) Garbage grinders, water closets and urinals shall not discharge into a trade waste system.I

7.4.2.2. Connection of Overflows from Rainwater Tanks

1) An overflow from a rainwater tank shall not be directly connected to a drainage system.I

7.4.2.3. Direct Connections

1) Two or more fixture outlet pipes that serve outlets from a single fixture that is listed in Clause 7.4.2.1.(1)(e) may be directly connected to a branch thatI

a)has a size of not less than 1.25 inches, and

b)is terminated above the flood level rim of a directly connected fixture to form an air break.

2) Fixture drains from fixtures that are listed in Subclauses 7.4.2.1.(1)(e)(i) and (ii) may be directly connected to a pipe thatI

a)is terminated to form an air break above the flood level rim of a fixture that is directly connected to a sanitary drainage system, and

b)is extended through the roof when fixtures on 3 or more storeys are connected to it (See A-7.4.2.1.(1)(a)(ii) and (e)(vi) in Appendix A).

3) Fixture drains from fixtures that are listed in Subclauses 7.4.2.1.(1)(e)(iii) to (vi) may be directly connected to a pipe thatI

a)is terminated to form an air break above the flood level rim of a fixture that is directly connected to a storm drainage system, and

b)is extended through the roof when fixtures on 3 or more storeys are connected to it.

7.4.2.4. Connections to Storm Drainage Systems

1) Except as provided in Sentence (2), all roof and paved areas shall drain to a storm drainage system.I

2) Building and site drainage need not connect directly to a storm drainage system where storm water conservation measures are being employed and it can be demonstrated there will be no impact on adjacent properties.

7.4.3. Location of Fixtures

7.4.3.1. Urinals

1) Urinals shall not be installed adjacent to wall and floor surfaces that are pervious to water. (See Article 3.7.2.6. of Division B.)I

7.4.3.2. Restricted Locations of Indirect Connections and Traps

1) Indirect connections or any trap that may overflow shall not be located in a crawl space or any other unfrequented area.I

7.4.3.3. Equipment Restrictions Upstream of Grease Interceptors

1) Except as provided in Sentence (2), equipment discharging waste with organic solids shall not be located upstream of a grease interceptor. (See Appendix A.) I

2) An organic solids interceptor may be installed upstream of a grease interceptor.I

7.4.3.4. Fixtures Located in Chemical Storage Locations

1) A floor drain or other fixture located in an oil transformer vault, a high voltage room or any room where flammable, dangerous or toxic chemicals are stored or handled shall not be connected to a drainage system.I

7.4.3.5. Macerating Toilet Systems

1) A macerating toilet system shall only be installed where no connection to a gravity sanitary drainage system is available.I

7.4.3.6. Drains Serving Elevator Pits

1) Where a drain is provided in an elevator pitI

a)it shall be connected directly to a sump well located outside the elevator pit, and

b)the drain pipe that connects the sump well to the drainage system shall have a backwater valve.

7.4.3.7. Fixture Location in Electrical Pull Pits

1) When drains are provided in an electrical pull pit which is located inside a building,

a)they shall not be connected directly to any drain or sewer,

b)a sump well shall be provided outside the pull pit room and the pull pit drain shall be connected to the sump well, and

the drain connected from the pull pit to the sump well shall be provided with a soft seated check valve.

7.4.4. Treatment of Sewage and Wastes

7.4.4.1. Sewage Treatment

1) Where a fixture or equipment discharges sewage or waste that may damage or impair the sanitary drainage system or the functioning of a public or private sewage disposal system, provision shall be made for treatment of the sewage or waste before it is discharged to the sanitary drainage system.I

7.4.4.2. Cooling of Hot Water or Sewage

1) Where a fixture discharges sewage or clear-water waste that is at a temperature above 65C, provision shall be made for cooling of the waste to 65C or less before it is discharged to the sanitary drainage system.I

2) Where a fixture discharges clear-water waste that is at a temperature above 40C, provision shall be made for cooling of the waste to 40C or less before it is discharged to the storm drainage system.

7.4.4.3. Grease Interceptors

1) Where a fixture discharges sewage that includes fats, oils or grease and is located in a public kitchen, in a restaurant or in a care or detention occupancy, it shall discharge through a grease interceptor. (See Appendix A.)I

2) Where the discharge from a fixture may contain oil or gasoline, an oil interceptor shall be installed. (See Article 7.5.5.2. for venting requirements for oil interceptors.)I

3) Where a fixture discharges sand, grit or similar materials, an interceptor designed for the purpose of trapping such discharges shall be installed.I

4) Every interceptor shall have sufficient capacity to perform the service for which it is provided.I

7.4.4.4. Neutralizing and Dilution Tanks

1) Where a fixture or equipment discharges corrosive or acid waste, it shall discharge into a neutralizing or dilution tank that is connected to the sanitary drainage system throughI

a)a trap, or

b)an indirect connection.

(See Appendix A.)

2) Each neutralizing or dilution tank shall have a method for neutralizing the liquid.I

7.4.5. Traps

7.4.5.1. Traps for Sanitary Drainage Systems

1) Except as provided in Sentences (2), (3), (4) and (5) and in Article 2.4.5.2., every fixture shall be protected by a separate trap.I

2) One trap may protectI

a)all the trays or compartments of a 2- or 3-compartment sink,

b)a 2-compartment laundry tray, or

c)2 similar single compartment fixtures located in the same room.

(See Appendix A.)

3) One trap may serve a group of floor drains or shower drains, a group of washing machines or a group of laboratory sinks if the fixtures I

a)are in the same room, and

b)are not located where they can receive food or other organic matter.

(See Appendix A.)

4) An indirectly connected fixture that can discharge only clear-water waste other than a drinking fountain need not be protected by a trap.I

(See Clause 7.4.2.1.(1)(e) for indirect connections.)

5) An interceptor with an effective water seal of not less than 38 mm may serve as a trap. (See Appendix A.)I

6) Where a domestic dishwashing machine equipped with a drainage pump discharges through a direct connection into the fixture outlet pipe of an adjacent kitchen sink or disposal unit, the pump discharge line shall rise as high as possible to just under the counter and connectI

a)on the inlet side of the sink trap by means of a Y fitting, or

b)to the disposal unit.

7.4.5.2. Sumps and Traps for Storm Drainage Systems

1) Where a storm drainage system is connected to a public sewer, a sump shall be installed between any opening in the system and the sewer except that no sump is required if the opening is the upper end of a leader that terminates.I

a)at a roof that is used only for weather protection,

b) not less than 1 m above or not less than 3.5 m in any other direction from any air inlet, openable window or door, and

c)not less than 1.8 m from a property line.

(See Appendix A.)

2) A floor drain that drains to a storm drainage system shall be protected by a trap thatI

a)is located between the floor drain and a leader, storm building drain or storm building sewer,

b)may serve all floor drains located in the same room, and

c)need not be protected by a vent pipe.

3) Where freezing conditions could cause storm drainage systems to freeze due to air circulation within the piping, a trap with a cleanout shall be installed in a heated location.I

7.4.5.3. Connection of Subsoil Drainage Pipe to a Storm Drainage System

1) A subsoil drainage pipe shall be connected to a sump and then to a storm sewer or combined sewer, but shall not be connected to a sanitary sewer.See Appendix A.)I

7.4.5.4. Location and Cleanout for Building Traps

1) Where a building trap is installed it shallI

a)be provided with a cleanout fitting on the upstream side of and directly over the trap,

b)be located upstream of the building cleanout, and

c)be located

i)inside the building as close as practical to the place where the building drain leaves the building, or

ii)outside the building in a manhole.

(See Appendix A.)
7.4.5.5. Trap Seals

1) Provision shall be made for maintaining the trap seal of a floor drain byI

a)the use of a trap seal primer,

b)using the drain as a receptacle for an indirectly connected drinking fountain, or

c)other equally effective means.

(See Appendix A.)

7.4.6. Arrangement of Drainage Piping

7.4.6.1. Separate Systems

1) No vertical soil-or-waste pipe shall conduct both sewage and storm water.I

2) A combined building drain shall not be installed. (See A-7.1.2.1.(2) in Appendix A.)I

3) There shall be no unused open ends in a drainage system and dead ends shall be so graded that water will not collect in them.I

7.4.6.2. Location of Soil-or-Waste Pipes

1) A soil-or-waste pipe shall not be located directly aboveI

a)non-pressure potable water storage tanks,

b)manholes in pressure potable water storage tanks, or

c)food-handling or food-processing equipment.

7.4.6.3. Sumps or Tanks
(See Appendix A.)

1) Piping that is too low to drain into a building sewer by gravity shall be drained to a sump or receiving tank.I

2) Where the sump or tank receives sewage, it shall be water- and air-tight and shall be vented.I

3) Equipment such as a pump or ejector that can lift the contents of the sump or tank and discharge it into the building drain or building sewer shall be installed.I

4) Where the equipment does not operate automatically, the capacity of the sump shall be sufficient to hold at least a 24 h accumulation of liquid.I

5) Where there is a building trap, the discharge pipe from the equipment shall be connected to the building drain downstream of the trap.I

6) The discharge pipe from every pumped sump shall be equipped with a union, a check valve and a shut-off valve installed in that sequence in the direction of discharge.I

7) The discharge piping from a pump or ejector shall be sized for optimum flow velocities at pump design conditions.I

7.4.6.4. Protection from Backflow

1) Except as permitted in Sentence (2), a backwater valve or a gate valve that would prevent the free circulation of air shall not be installed in a building drain or in a building sewer. (See Appendix A.)I

2) A backwater valve may be installed in a building drain provided thatI

a)it is a “normally open” design conforming to

i)CAN/CSA-B70, “Cast Iron Soil Pipe, Fittings, and Means of Joining,”

ii)CAN/CSA-B181.1, “ABS Drain, Waste, and Vent Pipe and Pipe Fittings,”

iii)CAN/CSA-B181.2, “PVC Drain, Waste, and Vent Pipe and Pipe Fittings,” or

iv)CAN/CSA-B182.1, “Plastic Drain and Sewer Pipe and Pipe Fittings,” and

b)it does not serve more than one dwelling unit.

3) Except as provided in Sentences (4), (5), [ . . . ] where a building drain or a branch may be subject to backflow, a gate valve or a backwater valve shall be installed on every fixture drain connected to them when the fixture is located below the level of the adjoining street.I

4) Where the fixture is a floor drain, a removable screw cap may be installed on the upstream side of the trap.I

5) Where more than one fixture is located on a storey and all are connected to the same branch, the gate valve or backwater valve may be installed on the branch.I

6) Where a storm sump is provided there shall be a backwater valve within the sump and attached to the outlet pipe, except that a backwater valve is not required for properties used for commercial or industrial purposes where the sump and the piping entering the sump is above the level of the next upstream manhole in the street containing the public storm sewer. (See Appendix A.)I

7.4.6.5. Mobile Home Sewer Service

1) A building sewer intended to serve a mobile home shall beI

a)not less than 4 inches in size,

b)terminated above ground,

c)provided with

i)a tamperproof terminal connection that is capable of being repeatedly connected, disconnected and sealed,

ii)a protective concrete pad, and

iii)a means to protect it from frost heave, and

d)designed and constructed in accordance with good engineering practice.

7.4.7. Cleanouts

7.4.7.1. Cleanouts for Drainage Systems

1) Every sanitary drainage system and storm drainage system shall be provided with cleanouts that will permit cleaning of the entire system. (See Appendix A.)I

2) A cleanout fitting shall be provided on the upstream side and directly over every running trap.I

3) Every interior leader shall be provided with a cleanout fitting at the bottom of the leader or not more than 3 m upstream from the bottom of the leader.I

4) Where a cleanout is required on a building sewer 8 inches or larger in size, it shall be a manhole.I

5) A building sewer shall not change direction or slope between the building and public sewer or between cleanouts, except that pipes not more than 6 inches in size may change directionI

a)by not more than 5° every 3 m, or

b)by the use of fittings with a cumulative change in direction of not more than 45°.

6) Every building drain shall be provided with a cleanout fitting that is located as close as practical to the place where the building drain leaves the building. (See Appendix A.) I

7) Every soil-or-waste stack shall be provided with a cleanout fittingI

a)at the bottom of the stack,

b)not more than 3 m upstream of the bottom of the stack, or

c)on a Y fitting connecting the stack to the building drain or branch.

8) A cleanout shall be provided to permit the cleaning of the piping downstream of an interceptor.I

9) Cleanouts shall be installed so that the cumulative change in direction is not more than 90° between cleanouts in a drip pipe from a food receptacle or in a fixture drain serving a kitchen sink. (See Appendix A.)I

7.4.7.2. Size and Spacing of Cleanouts

1) Except as provided in Sentences (2) and (3), the size and spacing of cleanouts in nominally horizontal pipes of a drainage system shall conform to Table 7.4.7.2.I

Table 7.4.7.2.
Permitted Size and Spacing of Cleanouts
Forming Part of Sentence 7.4.7.2.(1)
Size of Drainage Pipe, inches Minimum Size of Cleanout, 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) The spacing between manholes serving a building sewerI

a)24 inches or less in size shall not exceed 90 m, and

b)over 24 inches in size shall not exceed 150 m.

3) The developed length of a building sewer between the building and the first manhole to which the building sewer connects shall not exceed 75 m.I

4) Where a building sewer connects to another building sewer other than by a manhole, the developed length between the building and the building sewer to which it connects shall not exceed 30 m.I

5) Cleanouts that allow rodding in one direction only shall be installed to permit rodding in the direction of flow.I

7.4.7.3. Manholes

1) A manhole including the cover shall be designed to support all loads imposed upon it.I

2) A manhole shall be provided withI

a)a cover that provides an airtight seal if located within a building,

b)a rigid ladder of a corrosion-resistant material where the depth exceeds 1 m, and

c)a vent to the exterior if the manhole is located within a building.

3) A manhole shall have a minimum horizontal dimension of 1 m, except that the top 1.5 m may be tapered from 1 m down to a minimum of 600 mm at the top.I

4) A manhole in a sanitary drainage system shall be channeled to direct the flow of effluent.I

7.4.7.4. Location of Cleanouts

1) Cleanouts and access covers shall be located so that their openings are readily accessible for drain cleaning purposes.I

2) A cleanout shall not beI

a)located in a floor assembly in a manner that may constitute a hazard, or

b)used as a floor drain.

3) There shall be no change of direction between a cleanout fitting and the trap that it serves.I

4) The piping between a cleanout fitting and the drainage piping or vent piping that it serves shall not change direction by more than 45°.I

5) Cleanouts serving fixtures in health care facilities, mortuaries, laboratories and similar occupancies, where contamination by body fluids is likely, shall be located a minimum of 150 mm above the flood level rim of the fixture.I

7.4.8. Minimum Slope and Length of Drainage Pipes

7.4.8.1. Minimum Slope

1) Except as provided in Articles 2.4.10.8. and 2.4.10.9., every drainage pipe that has a size of 3 inches or less, and every fixture drain shall have a downward slope in the direction of flow of at least 1 in 50. (See Appendix A.) I

7.4.8.2. Length of Fixture Outlet Pipes

1) Except for fixture outlet pipes installed in conformance with Sentence 7.4.5.1.(3), the developed length of every fixture outlet pipe shall not exceed 1 200 mm. (See Appendix A.) (See also A-7.4.5.1.(2) in Appendix A.) I

7.4.9. Size of Drainage Pipes

7.4.9.1. No Reduction in Size

1) A soil-or-waste pipe shall be of a size not less than the size ofI

a)a vent pipe that is connected to it, or

b)the largest soil-or-waste pipe that drains into it.

7.4.9.2. Serving Water Closets

1) The size of every drainage pipe that serves a water closet shall be not less than 3 inches.I

2) The size of every branch or building drain downstream of the third water closet fixture drain connection shall be not less than 4 inches.I

3) The size of every soil-or-waste stack that serves more than 6 water closets shall be not less than 4 inches.I

4) The discharge pipe serving a macerating toilet shall be not less than 3/4 inch in size with a hydraulic load of 4 fixture units.I

7.4.9.3. Size of Fixture Outlet Pipes

1) Except as provided in Sentence (2), the size of every fixture outlet pipe shall conform to Table 7.4.9.3.I

2) The part of the fixture outlet pipe that is common to 3 compartments of a sink shall be one size larger than the largest fixture outlet pipe of the compartments that it serves. (See Appendix A.)I

Table 7.4.9.3.
Minimum Permitted Size of Fixture Outlet Pipe and Hydraulic Loads for Fixtures(1)
Forming Part of Sentences 7.4.9.3.(1) and 7.4.10.2(1)
Fixture Minimum Size of Fixture Outlet Pipe, inches Hydraulic Load,
fixture units
Autopsy table 2
Bathroom group    
(a) with flush tank n/a 6
(b) with direct flush valve n/a 8
Bathtub (with or without shower)
Bath: foot, sitz or slab
Beer cabinet
Bidet 1
Clothes washer    
(a) domestic(1) n/a 1½ with 1½-in. trap
(b) commercial n/a 2 with 1½-in. trap
Dental unit or cuspidor 1
Dishwasher    
(a) domestic type 1½ no load when connected to garbage grinder or domestic sink
(b) commercial type 2 3
Drinking fountain ½
Floor drain(2) 2 2 with 2-in. trap
    3 with 3-in. trap
Garbage grinder, commercial type 2 3
Icebox 1
Laundry tray    
(a) single or double units or 2 single units with common trap
(b) 3 compartments 2
Lavatory    
(a) barber or beauty parlor
(b) dental 1
(c) domestic type, single or 1 with 1¼-in. trap
2 single with common trap   1½ with 1½-in. trap
(d) multiple or industrial type according to Table 7.4.10.2.
Potato peeler 2 3
Shower drain    
(a) from 1 head
(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
(b) Other sinks 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
(ii) other types 2 3
Water closet    
(a) with flush tank 3 4
(b) with direct flush valve 3 6
Notes to Table 7.4.9.3.

(1)  See Appendix A.
(2)  No hydraulic load for emergency floor drains.

3) Where clothes washers do not drain to a laundry tray, the trap inlet shall be fitted with a vertical standpipe that is not less than 600 mm long measured from the trap weir and terminates above the flood level rim of the clothes washer. (See Appendix A.)I

7.4.9.4. Size of Building Drain and Building Sewer

1) The size of every building drain and building sewer connected to the public sewer system downstream of the main cleanout (see Sentence 7.4.7.1.(6)) shall be not less than 4 inches.I

7.4.9.5. Offset in Leaders

1) No change in the size of a leader with a nominally horizontal offset is required if the offsetI

a)is located immediately under the roof,

b)is not more than 6 m long, and

c)has a slope of not less than 1 in 50.

2) If the horizontal offset is more than 6 m long, the leader shall conform to Table 7.4.10.9.I

7.4.10. Hydraulic Loads

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

1) The hydraulic load on a pipe is the total load fromI

a)every fixture that is connected to the system upstream of the pipe,

b)every fixture for which provision is made for future connection upstream of the pipe, and

c)all roofs and paved surfaces that drain into the system upstream of the pipe.

7.4.10.2. Hydraulic Loads for Fixtures

1) The hydraulic load from a fixture that is listed in Table 7.4.9.3. is the number of fixture units set forth in the Table.I

2) Except as provided in Sentence (1), the hydraulic load from a fixture that is not listed in Table 7.4.9.3. is the number of fixture units set forth in Table 7.4.10.2. for the trap of the size that serves the fixture.I

Table 7.4.10.2.
Permitted Hydraulic Load from a Fixture Based on Size of Trap
Forming Part of Sentence 7.4.10.2.(2)
Size of trap, inches Hydraulic Load, fixture units
1
2
2 3
4
3 5
4 6
7.4.10.3. Hydraulic Loads from Fixtures with a Continuous Flow

1) Except as provided in Sentence (2), the hydraulic load from a fixture that produces a continuous flow, such as a pump or an air-conditioning fixture, is 31.7 fixture units for each litre per second of flow.I

2) Where a fixture or equipment that produces a continuous or semi-continuous flow drains to a combined sewer or to a storm sewer, the hydraulic load from the fixture is 900 L for each litre per second of flow.I

7.4.10.4. Hydraulic Loads from Roofs or Paved Surfaces

1) Except as provided in Sentence (2), the hydraulic load in litres from a roof or paved surface is the maximum 15 min rainfall determined in conformance with Subsection 1.1.3 of Division B, multiplied by the sum of

a)the area in square metres of the horizontal projection of the surface drained, and

b)one-half the area in square metres of the largest adjoining vertical surface.

(See Appendix A.)

2) Flow control roof drains may be installed providedI

a)the maximum drain down time does not exceed 24 h,

b)the roof structure has been designed to carry the load of the stored water,

c)one or more scuppers are installed so that the maximum depth of water on the roof cannot exceed 150 mm,

d)they are located not more than 15 m from the edge of the roof and not more than 30 m from adjacent drains, and

e)there is at least one drain for each 900 m2.

3) Hydraulic loads in litres per second for flow control roof drains and restricted paved area drains shall be determined according to rain intensity-duration frequency curves as compiled by Environment Canada using 25-year frequencies.I

7.4.10.5. Conversion of Fixture Units to Litres

1) Except as provided in Sentence 7.4.10.3.(2), where the hydraulic load is to be expressed in litres, fixture units shall be converted as follows:I

a)when the number of fixture units is 260 or fewer, the load is 2 360 L, and

b)when the number of fixture units exceeds 260, the load is 9.1 L for each fixture unit.

7.4.10.6. Hydraulic Loads to Soil-or-Waste Pipes

1) Except as provided in Sentence (2), the hydraulic load that is drained to every soil-or-waste stack shall conform to Table 7.4.10.6.A.I

2) Where the nominally horizontal offset in a soil-or-waste stack is 1.5 m or more, the hydraulic load that is served by it shall conform to Table 7.4.10.6.B or Table 7.4.10.6.C, whichever is the less restrictive.I

Table 7.4.10.6.A.
Maximum Permitted Hydraulic Load Drained to a Soil-or-Waste Stack
Forming Part of Sentence 7.4.10.6.(1)
Size of Stack, inches Maximum Hydraulic Load, fixture units Maximum Fixture Units Drained from any 1 Storey
     2     2
     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 7.4.10.6.B.
Maximum Permitted Hydraulic Load Drained to a Branch
Forming Part of Sentence 7.4.10.6.(2) and Article 7.4.10.7.
Size of Branch, inches Maximum Hydraulic Load, fixture units
    2
    3
2     6
   12
3    27
4   180
5   390
6   700
8 1 600
10 2 500
12 3 900
Table 7.4.10.6.C.
Maximum Permitted Hydraulic Load Drained to a Sanitary Building Drain or Sewer
Forming Part of Sentence 7.4.10.6.(2) and Article 7.4.10.8.
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
7.4.10.7. Hydraulic Loads on Branches

1) The hydraulic load that is drained to a branch shall conform to Table 7.4.10.6.B.I

7.4.10.8. Hydraulic Loads on Sanitary Building Drains or Sewers

1) The hydraulic load that is drained to a sanitary building drain or a sanitary building sewer shall conform to Table 7.4.10.6.C.I

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

1) The hydraulic load that is drained to a storm building drain, a storm building sewer or a combined building sewer shall conform to Table 7.4.10.9.I

Table 7.4.10.9.
Maximum Permitted Hydraulic Load Drained to a Storm Building Drain or Sewer
or a Combined Building Sewer

Forming Part of Article 7.4.10.9.
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 2 390 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
7.4.10.10. Hydraulic Loads to Roof Gutters

1) The hydraulic load that is drained to a roof gutter shall conform to Table 7.4.10.10.I

Table 7.4.10.10.
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
7.4.10.11. Hydraulic Loads on Leaders

1) The hydraulic load that is drained to a leader shall conform to Table 7.4.10.11.I

Table 7.4.10.11.
Maximum Permitted Hydraulic Load Drained to a Leader
Forming Part of Article 7.4.10.11.
Circular Leader Non-Circular Leader
Size of Leader, inches Maximum Hydraulic Load, L Area of Leader, cm2 Maximum Hydraulic Load, L
2  1 700  20.3  1 520
 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
7.4.10.12. Hydraulic Loads from Fixtures with a Semi-continuous Flow

1) The hydraulic load from a fixture or equipment that produces a semi-continuous flow shall conform to Table 7.4.10.12.I

Table 7.4.10.12.
Maximum Permitted Hydraulic Load from Fixtures with a Semi-continuous Flow
Forming Part of Sentence 7.4.10.12.(1)
Trap Size, inches Flow, L/s Hydraulic Load, fixture units
0.00 - 0.090 3
2 0.091 - 0.190 6
3 0.191 - 0.850 27
4 0.851 - 5.700 180
7.4.10.13. Design of Storm Sewers

1) Except as provided in Sentences 7.4.10.4.(1) and (2), and Article 7.4.10.9., storm sewers may be designed in accordance with good engineering practice.I