Division B
Acceptable Solutions

Part 7 — Plumbing Systems

Section 7.6. Potable Water Systems

7.6.1. Arrangement of Piping

7.6.1.1. Design, Fabrication and Installation

1) Potable water systems shall be designed, fabricated and installed in accordance with good engineering practice, such as that described in the ASHRAE Guide and Data Books, the ASHRAE Handbooks and ASPE Data Books. (See Appendix A.)I

2) Every fixture supplied with separate hot and cold water controls shall have the hot water control on the left and the cold on the right.I

3) In 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 byI

a)recirculation, or

b)a self-regulating heat tracing system.

7.6.1.2. Drainage

1) A water distribution system shall be installed so that the system can be drained or blown out with air.I

7.6.1.3. Shut-off Valves

1) Every 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.I

2) Every 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.I

3) Except for risers that serve only one dwelling unit, every riser shall be provided with a shut-off valve located at the source of supply.I

4) Each fixture shall be provided with shut-off valves, located on each water supply serving the fixture.I

5) In 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.)I

6) Deleted.

7) Every pipe that supplies water to a hot water tank shall be provided with a shut-off valve located close to the tank.I

7.6.1.4. Protection for Exterior Water Supply

1) Every pipe that passes through an exterior wall to supply water to the exterior of the building shall be provided withI

a)a frost-proof hydrant, or

b)a stop-and-waste cock located inside the building and close to the wall.

7.6.1.5. Check Valves

1) A 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.I

7.6.1.6. Flushing Devices

1) Every 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.I

2) Where a manually operated flushing device is installed it shall serve only one fixture.I

7.6.1.7. Relief Valves

1) In 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 valveI

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) Every hot water tank of a storage-type service water heater shall be equipped with a temperature-relief valve with a temperature-sensing elementI

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) A pressure-relief valve and temperature-relief valve may be combined where Sentences (1) and (2) are complied with.I

4) Every indirect service water heater shall be equipped withI

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 shallI

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.)

6) The temperature-relief valve required in Clause (4)(b) shallI

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) No 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.I

8) A vacuum-relief valve shall be installed when any tank may be subject to back-siphonage.I

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).I

10) The drain pan shallI

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.

7.6.1.8. Solar Domestic Hot Water Systems

1) Systems for solar heating of potable water shall be installed in conformance with CAN/CSA-F383, “Installation Code for Solar Domestic Hot Water Systems.”I

7.6.1.9. Water Hammer

1) Provision shall be made to protect the water distribution system from the adverse effects of water hammer. (See Appendix A.)I

7.6.1.10. Mobile Home Water Service

1) A water service pipe intended to serve a mobile home shallI

a)be not less than 3/4 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.

7.6.1.11. Thermal Expansion

1) Protection against thermal expansion shall be required when a check valve is required by Article 7.6.1.5., a backflow preventer by Article 7.6.2.6., or a pressure-reducing valve by Article 7.6.3.3. (See Appendix A.)I

7.6.2. Protection from Contamination

7.6.2.1. Connection of Systems

1) Except 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.I

2) A 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.I

3) Backflow preventers shall be selected, installed, maintained and field tested in conformance with the Water Works By-Law.I

7.6.2.2. Back-Siphonage

1) Potable 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).I

2) Except as provided in Sentence 7.6.2.10.(2), back-siphonage shall be prevented by the installation ofI

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,

h)a dual check valve backflow preventer,

i)a laboratory faucet type vacuum breaker, or

j)a dual check valve backflow preventer with vent.

7.6.2.3. Backflow Caused by Back Pressure

1) Potable 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). I

2) Except as provided in Article 7.6.2.4., backflow caused by back pressure of non-toxic substances into a potable water system shall be prevented by the installation ofI

a)an air gap,

b)a dual check valve backflow preventer with atmospheric port,

c)a dual check valve backflow preventer,

d)a dual check valve backflow preventer with vent,

e)a double check valve assembly, or

f)a reduced pressure principle backflow preventer.

3) Backflow caused by back pressure of toxic substances into a potable water system shall be prevented by the installation ofI

a)an air gap, or

b)a reduced pressure principle backflow preventer.

7.6.2.4. Backflow from Fire Protection Systems

1) Backflow 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.I

2) Backflow 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.I

3) Deleted.

4) Deleted.

7.6.2.5. Separation of Water Supply Systems

1) No private water supply system shall be interconnected with a public water supply system.I

7.6.2.6. Premise Isolation

1) In 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.)I

7.6.2.7. Hose Bibb

1) Where 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.I

7.6.2.8. Cleaning of Systems

1) A newly installed part of a potable water system shall be cleaned and then flushed with potable water before the system is put into operation.I

7.6.2.9. Air Gap

1) An air gap shall not be located in a noxious environment.I

2) Every 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.I

(See Appendix A.)
7.6.2.10. Vacuum Breakers

1) Where 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.I

2) Where 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 pressureI

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 150 mm aboveI

a)the flood level rim of a fixture or tank, or

b)the highest point open to atmosphere in an irrigation system.

4) A pressure vacuum breaker shall be installed so that the critical level is not less than 300 mm aboveI

a)the flood level rim of a fixture or tank, or

b)the highest point open to atmosphere in an irrigation system.

7.6.2.11. Tank-Type Water Closets

1) Tank-type water closets shall be provided with a back-siphonage preventer in conformance with Sentence 7.2.10.10.(2).I

7.6.2.12. Backflow Preventers

1) No bypass piping or other device capable of reducing the effectiveness of a backflow preventer shall be installed in a water supply system.I

7.6.3. Size and Capacity of Pipes

(See Appendix A.)
7.6.3.1. Design

1) Every water distribution system shall be designed to provide peak demand flow when the flow pressures at the supply openings conform to Table 7.6.3.1I

2) Except as permitted in Sentences 7.6.3.4.(2), (4), and (5), the maximum velocity in copper water pipes shall not exceed

a)1.5 metres/sec for cold water pipes,

b)1.2 metres/sec for hot water distribution systems and recirculating systems with operating temperatures not exceeding 60°C, or

c)0.9 metres/sec for hot water distribution systems and recirculating systems with operating temperatures exceeding 60°C.

Table 7.6.3.1.
Sizing of Water Distribution Systems
Forming Part of Sentences 7.6.3.1.(1), 7.6.3.2.(1), (2) and (3), and 7.6.3.4.(2)
Fixture or Device Minimum Size of
Supply Pipe, inches
Minimum Flow
Pressure,(1)
kPa (gauge)
Hydraulic Load, fixture units
Private Use Public Use
Bathroom group        
(a) with flush tank n/a n/a 6
(b) with direct flush valve n/a n/a 8
Bathtub (with or without shower) ½ 50 2 4
Clothes washer ½ 100 3
Dishwasher, domestic ½ 100 3
Drinking fountain 3/8 100 ½ 1
Hose bibb ½ 100   (2)   (2)
Lavatory 3/8 50 1 2
Sink        
(a) kitchen, domestic ½ 50 2
(b) kitchen, commercial ½ 50 4
(c) service ½ 50 3
(d) service with direct flush valve ¾ 100 5
Shower head ½ 50 2 4
Urinal        
(a) with flush tank ½ 50 3
(b) with direct flush valve ¾ 100 5
(c) with self-closing metering valve ½
Water Closet        
(a) with flush tank 3/8 50 3 5
(b) with direct flush valve 1 100 6 10
Notes to Table 7.6.3.1.

(1)  Measured immediately upstream of faucet or supply valve.
(2)  A continuous load of 0.38 L/s.
7.6.3.2. Hydraulic Load

1) Except as provided in Sentence (3), the hydraulic load of a fixture or device that is listed in Table 7.6.3.1. shall be the number of fixture units given in the Table.I

2) Except as provided in Sentences (1) and (3), the hydraulic load of a fixture that is not listed in Table 7.6.3.1. is the number of fixture units listed in Table 7.6.3.2.I

Table 7.6.3.2.
Hydraulic Loads of Fixtures Not Listed in Table 7.6.3.1.
Forming Part of Sentences 7.6.3.2.(2) and (3)
Size of Supply Pipe, inches Hydraulic Load, fixture units
Private Use Public Use
3/8 1 2
½ 2 4
¾ 3 6
1 6 10

3) Where 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 Table 7.6.3.1. and 7.6.3.2. when using a detailed engineering design method.I

4) Where fixtures for one and two family dwellings are supplied with both hot and cold water, the hydraulic loads for maximum separate demands for water distribution piping shall be not less than 100 per cent of the hydraulic load of the fixture units given in Table 7.6.3.1. (private use) or Table 7.6.3.2. (private use).

7.6.3.3. Static Pressure

1) Where 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.I

Table 7.6.3.3.
Fixture Unit Table
Forming Part of Sentences 7.6.3.4.(2), (4) and (5)
Fixture Unit Table for Determining Water Pipe Sizes for Single Family Dwellings and Duplexes (1) (2)
Nominal Pipe Size inches (3) Hydraulic Load, fixture units
½ 11
¾ 40
1 90
225
Notes to Table 7.6.3.3.

(1)  Minimum water pressure at property line shall be 200 kPa.
(2)  Total maximum length of water system shall be 90 metres.
(3)  The hydraulic load in fixture units for a water service pipe shall be determined from Table 7.6.3.1.
7.6.3.4. Size

1) Except as provided in Sentence (2), every water service pipe shall be sized according to the peak demand flow but shall not be less than 3/4 inch size.I

2) For one and two family dwellings, the size of a water service pipe that supplies a fixture or device shall be determined by Table 7.6.3.3., but shall not be less than 3/4 in.

3) Except as provided in Sentence (5), the size of a pipe that supplies a fixture or device shall conform to Table 7.6.3.1.I

4) For one and two family dwellings, the size of a water distribution system shall be determined by Table 7.6.3.3..

5) A tail piece or connector not more than 750 mm long and not less than 0.25 inch inside diameter may be used to supply water to a fixture.I