Division B
Acceptable Solutions

Part 2 — Plumbing Systems

Section 2.6. Potable Water Systems

2.6.1. Arrangement of Piping

2.6.1.1. Design
1) Intent StatementEvery fixture supplied with separate hot and cold water controls shall have the hot water control on the left and the cold on the right.
2) Intent StatementIn a hot water distribution system of a developed length of more than 30 m or supplying more than 4 storeys, the water temperature shall be maintained by
a) recirculation, or
b) a self-regulating heat tracing system.
2.6.1.2. Drainage
1) Intent StatementA water distribution system shall be installed so that the system can be drained or blown out with air.
2.6.1.3. Shut-off Valves
1) Intent StatementEvery water service pipe shall be provided with an accessible shut-off valve located as close as possible to where the water service pipe enters the building.
2) Intent StatementEvery pipe that conveys water from a gravity water tank or from a private water supply system shall be fitted with a shut-off valve at the source of supply.
3) Intent StatementExcept for risers that serve only one dwelling unit, every riser shall be provided with a shut-off valve located at the source of supply.
4) change beginEvery fixture shall be fitted with a shut-off valve, located on each water supply serving the fixture.change end

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5) Intent StatementIn buildings of residential occupancy that contain more than one dwelling unit, a shut-off valve shall be installed where the water supply enters each dwelling unit, so that, when the water supply to one suite is shut off, the water supply to the remainder of the building is not interrupted. (See Appendix A.)
6) change beginDeleted.change end

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7) Intent StatementEvery pipe that supplies water to a hot water tank shall be provided with a shut-off valve located close to the tank.
2.6.1.4. Protection for Exterior Water Supply
1) Intent StatementEvery pipe that passes through an exterior wall to supply water to the exterior of the building shall be provided with
a) a frost-proof hydrant, or
b) a stop-and-waste cock located inside the building and close to the wall.
2.6.1.5. Check Valves
1) Intent StatementA check valve shall be installed at the building end of a water service pipe where the pipe is made of plastic that is suitable for cold water use only.
2.6.1.6. Flushing Devices
1) Intent StatementEvery flushing device that serves a water closet or one or more urinals shall have sufficient capacity and be adjusted to deliver at each operation a volume of water that will thoroughly flush the fixture or fixtures that it serves.
2) Intent StatementWhere a manually operated flushing device is installed it shall serve only one fixture.
2.6.1.7. Relief Valves
1) Intent StatementIn addition to the requirements in Sentence (2), every hot water tank of a storage-type service water heater shall be equipped with a pressure-relief valve
a) designed to open when the water pressure in the tank reaches the rated working pressure of the tank, and
b) so located that the pressure in the tank shall not exceed the pressure at the relief valve by more than 35 kPa under any condition of flow within the distribution system.
2) Intent StatementEvery hot water tank of a storage-type service water heater shall be equipped with a temperature-relief valve with a temperature-sensing element
a) located within the top 150 mm of the tank, and
b) designed to open and discharge sufficient water from the tank to keep the temperature of the water in the tank from exceeding 99°C under all operating conditions.
3) Intent StatementA pressure-relief valve and temperature-relief valve may be combined where Sentences (1) and (2) are complied with.
4) Intent StatementEvery indirect service water heater shall be equipped with
a) a pressure-relief valve, and
b) a temperature-relief valve on every storage tank that forms part of the system.
5) Every pipe that conveys water from a temperature-relief, pressure-relief or combined temperature- and pressure-relief valve shall
a) be of a size at least equal to the size of the outlet of the valve,
b) be rigid, slope downward from the valve, and terminate with an indirect connection above a floor drain, sump, or other safe location, with an air break of not more than 300 mm,
c) have no thread at its outlet, and
d) be capable of operating at a temperature of not less than 99°C.
(See Appendix A.)

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6) Intent StatementThe temperature-relief valve required in Clause (4)(b) shall
a) have a temperature-sensing element located within the top 150 mm of the tank, and
b) be designed to open and discharge sufficient water to keep the temperature of the water in the tank from exceeding 99°C under all operating conditions.
7) Intent StatementNo shut-off valve shall be installed on the pipe between any tank and the relief valves or on the discharge lines from such relief valves.
8) Intent StatementA vacuum-relief valve shall be installed when any tank may be subject to back-siphonage.
9) A storage-type service water heater that is located in a ceiling or roof space, or over a floor of wood construction, shall be installed within a corrosion-resistant watertight drain pan, as described in Sentence (10).

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10) The drain pan shall
a) be not less than 50 mm larger than the tank and have side walls not less than 25 mm high,
b) be drained by a pipe two sizes larger than the relief valve discharge pipe, and
c) have a drain that is located directly under the relief valve discharge pipe and that discharges directly to a floor drain or other acceptable location.

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2.6.1.8. Solar Domestic Hot Water Systems
1) Systems for solar heating of potable water shall be installed in conformance with change beginCAN/CSA-F383, “Installation of Packaged Solar Domestic Hot Water Systems.”change end

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2.6.1.9. Water Hammer
1) Intent StatementProvision shall be made to protect the water distribution system from the adverse effects of water hammer. (See Appendix A.)
2.6.1.10. Mobile Home Water Service
1) Intent StatementA water service pipe intended to serve a mobile home shall
a) be not less than ¾ inch in size,
b) terminate above ground, and
c) be provided with
i) a tamperproof terminal connection that is capable of being repeatedly connected, disconnected and sealed,
ii) a protective concrete pad,
iii) a means to protect it from frost heave, and
iv) a curb stop and a means of draining that part of the pipe located above the frost line when not in use.
2.6.1.11. Thermal Expansion
1) Intent StatementProtection against thermal expansion shall be required when a check valve is required by Article 2.6.1.5., a backflow preventer by Article 2.6.2.6., or a pressure-reducing valve by Article 2.6.3.3.  (See Appendix A.)
2.6.1.12. change beginService Water Heaters
1) Intent StatementThermostat controls for electric storage-type service water heaters shall be set at a temperature of 60°C. (See Appendix A.)change end

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2.6.2. Protection from Contamination

2.6.2.1. Connection of Systems
1) Intent StatementExcept as provided in Sentence (2), connections to potable water systems shall be designed and installed so that non-potable water or substances that may render the water non-potable cannot enter the system.
2) Intent StatementA water treatment device or apparatus shall not be installed unless it can be demonstrated that the device or apparatus will not introduce substances into the system that may endanger health.
3) change beginBackflow preventers shall be selected, installed, maintained and field tested in conformance with the Water Works By-Law.

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4) [Deleted.]change end

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2.6.2.2. Back-Siphonage
1) Intent StatementPotable water connections to fixtures, tanks, vats or other devices not subject to pressure above atmospheric and containing other than potable water shall be installed so as to prevent back-siphonage in conformance with Sentence (2).
2) Intent StatementExcept as provided in Sentence 2.6.2.10.(2), back-siphonage shall be prevented by the installation of
a) an air gap,
b) an atmospheric vacuum breaker,
c) a pressure vacuum breaker,
d) a hose connection vacuum breaker,
e) a dual check valve backflow preventer with atmospheric port,
f) a double check valve assembly,
g) a reduced pressure principle backflow preventer,
i) a laboratory faucet type vacuum breaker, or
j) a dual check valve backflow preventer with vent.
2.6.2.3. Backflow Caused by Back Pressure
1) Intent StatementPotable water connections to fixtures, tanks, vats, boilers or other devices containing other than potable water and subject to pressure above atmospheric shall be arranged to prevent backflow caused by back pressure in conformance with Sentences (2) and (3).
2) Intent StatementExcept as provided in Article 2.6.2.4., backflow caused by back pressure of non-toxic substances into a potable water system shall be prevented by the installation of
a) an air gap,
b) a dual check valve backflow preventer with atmospheric port,
d) a dual check valve backflow preventer with vent,
e) a double check valve assembly, or
f) a reduced pressure principle backflow preventer.
3) Intent StatementBackflow caused by back pressure of toxic substances into a potable water system shall be prevented by the installation of
a) an air gap, or
b) a reduced pressure principle backflow preventer.
2.6.2.4. Backflow from Fire Protection Systems
1) Intent Statementchange beginBackflow caused by back-siphonage or back pressure from fire sprinkler systems where water treatment is not added shall be prevented by the installation of a double check valve assembly or an approved dual check valve when the building is sprinklered to NFPA 13D and a flow through system is installed.
2) Intent StatementBackflow caused by back-siphonage or back pressure from fire sprinkler or standpipe systems where water treatment is added shall be prevented by the installation of a reduced pressure principal backflow preventer. (See Appendix A.)
3) Intent StatementDeleted.
4) Intent StatementDeleted.change end

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2.6.2.5. Separation of Water Supply Systems
1) Intent StatementNo private water supply system shall be interconnected with a public water supply system.
2.6.2.6. Premise Isolation
1) Intent StatementIn addition to the backflow preventer required by this Subsection for buildings or facilities where a potentially severe health hazard may be caused by backflow, the potable water system shall be provided with premise isolation by the installation of a reduced pressure principle backflow preventer. (See Appendix A.)
2.6.2.7. Hose Bibb
1) Intent StatementWhere a hose bibb is installed outside a building, inside a garage or in an area where there is an identifiable risk of contamination, the potable water system shall be protected against backflow through the hose bibb.
2.6.2.8. Cleaning of Systems
1) Intent StatementA newly installed part of a potable water system shall be cleaned and then flushed with potable water before the system is put into operation.
2.6.2.9. Air Gap
1) Intent StatementAn air gap shall not be located in a noxious environment.
2) Intent StatementEvery air gap shall be not less than 25 mm high and at least twice the diameter of the opening of the water supply outlet in height. (See Appendix A.)
2.6.2.10. Vacuum Breakers
1) Intent StatementWhere the critical level is not marked on an atmospheric vacuum breaker or pressure vacuum breaker, the critical level shall be taken as the lowest point on the device.
2) Intent StatementWhere an atmospheric vacuum breaker is installed, it shall be located on the downstream side of the fixture control valve or faucet so that it will be subject to water supply pressure
a) only when the valve or faucet is open, and
b) for periods of continuous use not exceeding 12 h.
(See Appendix A.)
3) An atmospheric vacuum breaker shall be installed so that the critical level is at least the distance specified by the manufacturer at which the device will operate safely but not less than change begin150 mmchange end above
a) the flood level rim of a fixture or tank, or
b) the highest point open to atmosphere in an irrigation system.

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4) Intent StatementA pressure vacuum breaker shall be installed so that the critical level is not less than 300 mm above
a) the flood level rim of a fixture or tank, or
b) the highest point open to atmosphere in an irrigation system.
2.6.2.11. Tank-Type Water Closets
1) Intent StatementTank-type water closets shall be provided with a back-siphonage preventer in conformance with Sentence 2.2.10.10.(2).
2.6.2.12. Backflow Preventers
1) Intent StatementNo bypass piping or other device capable of reducing the effectiveness of a backflow preventer shall be installed in a water supply system.

2.6.3. Size and Capacity of Pipes

(See Appendix A.)
2.6.3.1. Design, Fabrication and Installation
change begin(See Appendix A.)change end
1) Intent StatementEvery water distribution system shall be designed to provide peak demand flow when the flow pressures at the supply openings conform to change beginthe plumbing supply fitting manufacturer’s specifications.change end
2) Intent StatementPotable  water systems shall be designed, fabricated and installed in accordance with good engineering practice, such as that described in the ASHRAE Handbooks and ASPE Data Books. (See Appendix A.)
3) change beginIn one- and two-family dwelling units and manufactured homes, multi-purpose systems that combine potable water systems and residential fire sprinkler systems shall be designed, fabricated and installed in accordance with NFPA 13D, “Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes.”change end

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2.6.3.2. Hydraulic Load
1) Intent StatementExcept as provided in Sentence (3), the hydraulic load of a fixture or device that is listed in Table 2.6.3.2.A shall be the number of fixture units given in the Table.
2) Intent StatementExcept as provided in Sentences (1) and (3), the hydraulic load of a fixture that is not listed in Table 2.6.3.2.A is the number of fixture units listed in Table 2.6.3.2.D.
3) Intent StatementWhere fixtures are supplied with both hot and cold water, the hydraulic loads for maximum separate demands shall be 75% of the hydraulic load of the fixture units given in Tables 2.6.3.2.A and 2.6.3.2.D when using a detailed engineering design method.
4) Intent Statementchange beginThe hydraulic load of urinals and water closets with direct flush valves shall be the number of fixture units listed in Tables 2.6.3.2.B and C. (See Appendix A.)
Table 2.6.3.2.A
Sizing of Water Distribution Systems(1)(2)
Forming part of Sentences 2.6.3.2.(1), (2) and (3), and 2.6.3.4.(2), (3) and (5)

Fixture or Device

Minimum Size of Supply Pipe, inches

Private Use Hydraulic Load, fixture units

Public Use Hydraulic Load, fixture units

Cold Hot Total Cold Hot Total

Bathroom group with 6 LPF flush tank(3)

n/a 2.7 1.5 3.6 - - -

Bathroom group with greater than 6 LPF flush tank(3)

n/a 4 3 6 - - -

Bathroom group with more than 3 fixtures

- - -

(4)

- - -
Bathtub with or without shower head ½ 1 1 1.4 3 3 4
Bathtub with ¾ inch spout ¾ 7.5 7.5 10 7.5 7.5 10
Bedpan washer 1 - - - 7.5 7.5 10
Bidet 1.5 1.5 2 - - -
Clothes washer 3.5 kg ½ 1 1 1.4 2.25 2.25 3
Clothes washer 6.8 kg ½ - - - 3 3 4

Clothes washer, commercial(5)

- - - - - - -
Dental lavatory - - - 1.5 1.5 2
Dental unit, cuspidor - - - 1 - 1

Dishwasher, commercial(5)

- - - - - - -
Dishwasher, domestic - 1.4 1.4 - - -
Drinking fountain or water cooler - - - 0.25 - 0.25
Hose bibb ½ 2.5 - 2.5 2.5 - 2.5
Hose bibb ¾ 3 - 3 6 - 6
Hose bibb, combination hot and cold ½ 1.9 1.9 2.5 1.9 1.9 2.5
Lavatory, 8.3 LPM or less 0.5 0.5 0.7 1.5 1.5 2
Lavatory, greater than 8.3 LPM 0.75 0.75 1 1.5 1.5 2
Sink, bar 0.75 0.75 1 1.5 1.5 2
Sink, clinic service faucet ½ - - - 2.25 2.25 3
Sink, clinic service with direct flush valve 1 - - - 6 - 6
Sink, kitchen commercial, per faucet ½ - - - 3 3 4
Sink, kitchen domestic, 8.3 LPM 1 1 1.4 1 1 1.4
Sink, kitchen domestic, greater than 8.3 LPM 1.5 1.5 2 1.5 1.5 2
Sink, laboratory - - - 1.5 1.5 2
Sink, laundry (1 or 2 compartments) 1 1 1.4 1 1 1.4
Sink, service or mop basin ½ - - - 2.25 2.25 3
Sink, washup, per faucet ½ - - - 1.5 1.5 2
Shower head, 9.5 LPM or less per head ½ 1 1 1.4 3 3 4
Shower head, greater than 9.5 LPM per head ½ 1.5 1.5 2 3 3 4
Shower, spray, multi-head, fixture unit per head (5) 1 1 1.4 3 3 4
Urinal, with direct flush valve ¾

(6)

-

(6)

(6)

-

(6)

Urinal, with flush tank 3 - 3 3 - 3
Urinal, with self-closing metering valve ½ 2 - 2 4 _ 4
Water closet, 6 LPF or less with flush tank 2.2 - 2.2 2.2 - 2.2
Water closet, greater than 6 LPF with flush tank 3 - 3 5 - 5
Water closet, with direct flush valve 1

(6)

-

(6)

(6)

-

(6)

Notes to Table 2.6.3.2.A:

(1) The fixture unit values in this Table are not applicable in certain assembly occupancies because of surges in use by the occupants. For such occupancies, refer to specific design information.
(2) For fixtures not indicated in this Table, refer to Table 2.6.3.2.D.
(3) Bathroom group is based on a ½-inch size bathtub supply pipe.
(4) Add additional fixture to the fixture load for bathroom group.
(5) Refer to manufacturer's recommendations.
(6) For fixture unit values for fixtures with direct flush valves, see Sentence 2.6.3.2.(4) and Tables 2.6.3.2.B and 2.6.3.2.C.
Table 2.6.3.2.B
Sizing of Water Distribution Systems for Urinals with Direct Flush Valves
Forming part of Sentences 2.6.3.2.(4) and 2.6.3.4.(5)
Number of Valves Individual Fixture Unit Assigned in Decreasing Values Fixture Units in Accumulative Values(1)
1 20 20
2 15 35
3 10 45
4 8 53
5 or more 5 each 58, plus 5 for each additional fixture in excess of 5
Notes to Table 2.6.3.2.B:

(1) The accumulative fixture unit values are the total values to be used in conjunction with Table 2.6.3.2.A.
Table 2.6.3.2.C
Sizing of Water Distribution Systems for Water Closets with Direct Flush Valves
Forming part of Sentences 2.6.3.2.(4) and 2.6.3.4.(5)
Number of Valves Individual Fixture Unit Assigned in Decreasing Values Fixture Units in Accumulative Values(1)
1 40 40
2 30 70
3 20 90
4 15 105
5 or more 10 for each public use
and
6 for each private use
115, plus 10 for each public use additional fixture in excess of 5
and
111, plus 6 for each private use additional fixture in excess of 5change end
Notes to Table 2.6.3.2.C:

(1) The accumulative fixture unit values are the total values to be used in conjunction with Table 2.6.3.2.A.
Table 2.6.3.2.D
Hydraulic Loads of Fixtures Not Listed in Table 2.6.3.2.A.
Forming part of Sentences 2.6.3.2.(2) and (3) and 2.6.3.4.(5)
Size of Supply Pipe, inches Hydraulic Load, fixture units
Private Use Public Use
1 2
½ 2 4
¾ 3 6
1 6 10
2.6.3.3. Static Pressure
1) Intent StatementWhere the static pressure at any fixture may exceed 550 kPa, a pressure-reducing valve shall be installed to limit the maximum static pressure at the fixture to 550 kPa.
2.6.3.4. Size
1) Intent StatementEvery water service pipe shall be sized according to the peak demand flow but shall not be less than ¾ inch size.
2) Intent StatementExcept as provided in Sentence (3), the size of a change beginsupply pipe that serveschange end a fixture shall conform to change beginTable 2.6.3.2.Achange end
3) Intent Statementchange beginFor fixtures listed in Table 2.6.3.2.A that have a permitted supply pipe size of 3/8 inch,change end a connector not more than 750 mm long and not less than change begin6.3 mmchange end inside diameter may be used to supply water to the fixture.
4) change beginReserved.change end

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5) Intent Statementchange beginWhere both hot and cold water is supplied to fixtures in residential buildings containing one or two dwelling units or row houses with separate water service pipes, the water system may be sized in accordance with Table 2.6.3.4., where
a) the hydraulic loads for maximum separate demands on water distribution system piping are not less than 100% of the total hydraulic load of the fixture units given in Tables 2.6.3.2.A, B, C or D for private use,
b) the minimum water pressure at the entry to the building is 200 kPa, and
c) the total maximum length of water system is 90 m.
(See Appendix A.)change end
Table 2.6.3.4.
change beginWater Pipe Sizing for Buildings Containing One or Two Dwelling Units or Row Houses with Separate Water Service Pipes
Forming part of Sentence 2.6.3.4.(5)
Size of Water Pipe, inches Water Velocity, m/s(1)
3.0 2.4 1.5
Hydraulic Load, fixture units
½ 8 7 4
¾ 21 16 9
1 43 31 18
83 57 30change end
Notes to Table 2.6.3.4.:

(1) Table 2.6.3.4. is not intended to limit water velocities that are permitted by Sentence 2.6.3.5.(1).
2.6.3.5. change beginVelocity
1) Intent StatementThe maximum permitted water velocities shall be those recommended by the pipe and fitting manufacturer.change end