Potable water systems (7.6)

(1)Provision shall be made to protect the water distribution system from the adverse effects of water hammer. (See Note A-7.6.1.9.(1))

(1)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)Reserved.

(3)Backflow preventers shall be selected and installed in conformance with CSA B64.10, "Selection and installation of backflow preventers."

(3.1)No connection shall be made between a potable water system supplied with water from a drinking water system and any other potable water system without the consent of the water purveyor.

(1)Every potable water system that supplies a fixture or tank that is not subject to pressures above atmospheric shall be protected against back-siphonage by a backflow preventer.

(2)Where a potable water supply is connected to a boiler, tank, cooling jacket, lawn sprinkler system or other device where a non-potable fluid may be under pressure that is above atmospheric or the water outlet may be submerged in the non-potable fluid, the water supply shall be protected against backflow by a backflow preventer.

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

(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.

(1)A backflow preventer shall not be required in residential full flow-through fire sprinkler/standpipe systems in which the pipes and fittings are constructed of potable water system materials.

(2)Except as required by Sentence (4), potable water system connections to fire sprinkler and standpipe systems shall be protected against backflow caused by back-siphonage or back pressure in conformance with Clauses (a) to (g), as applicable:

(a)residential partial flow-through fire sprinkler/standpipe systems in which the pipes and fittings are constructed of potable water system materials shall be protected by a dual check valve backflow preventer conforming to

(i)CSA B64.6, "Dual check valve (DuC) backflow preventers," or

(ii)CSA B64.6.1, "Dual check valve backflow preventers for fire protection systems (DuCF),"

(b)provided that the systems do not use antifreeze or other additives of any kind and that all pipes and fittings are constructed of potable water system materials, Class 1 fire sprinkler/standpipe systems shall be protected by a single or dual check valve backflow preventer conforming to

(i)CSA B64.6, "Dual check valve (DuC) backflow preventers," or

(ii)CSA B64.9, "Single check valve backflow preventers for fire protection systems (SCVAF),"

(c)provided that the systems do not use antifreeze or other additives of any kind, Class 1 fire sprinkler/standpipe systems not covered by Clause (b) as well as Class 2 and Class 3 fire sprinkler/standpipe systems shall be protected by a double check valve backflow preventer conforming to

(i)CSA B64.5, "Double check valve (DCVA) backflow preventers," or

(ii)CSA B64.5.1, "Double check valve backflow preventers for fire protection systems (DCVAF),"

(d)Class 1, Class 2 or Class 3 fire sprinkler/standpipe systems in which antifreeze or other additives are used shall be protected by a reduced pressure principle backflow preventer conforming to

(i)CSA B64.4, "Reduced pressure principle (RP) backflow preventers," or

(ii)CSA B64.4.1, "Reduced pressure principle backflow preventers for fire protection systems (RPF)," installed on the portion of the system that uses the additives and the balance of the system shall be protected as required by Clause (b) or (c),

(e)Class 4 and Class 5 fire sprinkler/standpipe systems shall be protected by a reduced pressure principle backflow preventer conforming to

(i)CSA B64.4, "Reduced pressure principle (RP) backflow preventers," or

(ii)CSA B64.4.1, "Reduced pressure principle backflow preventers for fire protection systems (RPF),"

(f)Class 6 fire sprinkler/standpipe systems shall be protected by a double check valve backflow preventer conforming to

(i)CSA B64.5, "Double check valve (DCVA) backflow preventers," or

(ii)CSA B64.5.1, "Double check valve backflow preventers for fire protection systems (DCVAF)."

(g)where a potentially severe health hazard may be caused by backflow, Class 6 fire sprinkler/standpipe systems shall be protected by a reduced pressure principle backflow preventer conforming to

(i)CSA B64.4, "Reduced pressure principle (RP) backflow preventers," or

(ii)CSA B64.4.1, "Reduced pressure principle backflow preventers for fire protection systems (RPF)."

(3)Backflow preventers required by Sentence (2) shall be installed upstream of the fire department pumper connection.

(4)Where a reduced pressure principle backflow preventer is required on a water service pipe at a fire service connection located on the same premises as the fire service pipe in Class 3, 4, 5 and 6 fire sprinkler/standpipe systems, a reduced pressure principle backflow preventer conforming to CSA B64.4.1, "Reduced pressure principle backflow preventers for fire protection systems (RPF)," shall also be required on the fire service connection.

(1)Buildings or facilities where a moderate hazard or severe hazard may be caused by backflow shall be provided with premise isolation of the potable water system by the installation of a backflow preventer selected in accordance with Clauses 5.3.4.2.(b) and (c) of CSA B64.10, "Selection and installation of backflow preventers."

(2)Buildings of residential occupancy within the scope of Part 9 are not required to be isolated unless they have access to an auxiliary water supply.

(3)Except as provided in Sentence (1), where no direct connection exists between the auxiliary water supply and the potable water system, premise isolation shall be provided by a dual check valve backflow preventer conforming to CSA B64.6, "Dual check valve (DuC) backflow preventers."

(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. (See Note A-7.6.2.8.(1))

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

(2)Air gaps shall be not less than 25 mm high and at least twice the diameter of the opening of the water supply outlet in height.

(1)Where the critical level is not marked on an atmospheric vacuum breaker, pressure vacuum breaker or spill-resistant pressure vacuum breaker, the critical level shall be taken as the lowest point on the device.

(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 pressure

(a)only when the valve or faucet is open, and

(b)for periods of continuous use not exceeding 12 h.

(3)An atmospheric vacuum breaker shall be installed so that the critical level is at least the distance specified by the manufacturer for safe operation of the device, but not less than 25 mm above

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

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

(4)A pressure vacuum breaker or spill-resistant 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 the atmosphere in an irrigation system.

(1)Water distribution systems shall be designed to provide peak demand flow when the flow pressures at the supply openings conform to the plumbing supply fitting manufacturer's specifications.

(2)Potable water systems shall be designed, fabricated and installed in accordance with good engineering practice, such as that described in the ASHRAE Handbooks and ASPE Plumbing Engineering Design Handbooks.

(3)Reserved.

(4)Pipes that supply a fixture shall have a capacity that will produce a flow in the fixture that will flush the fixture and keep it in a sanitary condition.

(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.

(1)Water service pipes shall be sized according to the peak demand flow but shall not be less than NPS3/4 .

(2)Except as provided in Sentence (3), the nominal pipe size of a supply pipe that serves a fixture shall conform to Table 7.6.3.2.-A.

(3)For fixtures listed in Table 7.6.3.2.-A that are permitted to have an NPS3/8 supply pipe, a connector not more than 750 mm long and not less than NPS1/4 may be used to supply water to the fixture.

(4)No water system between the point of connection with the water service pipe or the water meter and the first water distribution pipe that supplies a water heater that serves more than one fixture shall be sized less than NPS 3/4.

(5)Except as permitted in Sentence (6), where 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 7.6.3.4., 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 Table 7.6.3.2.-A, 7.6.3.2.-B, 7.6.3.2.-C or 7.6.3.2.-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 the water system is 90 m.

(See Note A-7.6.3.4.(5))

(6)Where both hot and cold water is supplied to fixtures in a house containing only one dwelling unit, the water service pipe is permitted to be a minimum of NPS ¾ in provided,

(a)a minimum NPS ¾ water supply piping located in the basement or lower level is extended to the base of every hot and cold riser that serves a maximum of one bathroom group and to the last water supply branch serving any basement bathroom group, fixture supply or hose bibb, and

(b)the total hydraulic load is not more than 26 fixture units, using the values given in Table 7.6.3.2.-A.

(1)The maximum permitted water velocities shall be those recommended by the pipe and fitting manufacturer.

(1)Except as provided in Sentence (3), the hydraulic load of a fixture or device that is listed in Table 7.6.3.2.-A shall be the number of fixture units given in the Table.

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

(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 Tables 7.6.3.2.-A and 7.6.3.2.-D when using a detailed engineering design method.

(4)The hydraulic load of urinals and water closets with direct flush valves shall be the number of fixture units listed in Tables 7.6.3.2.-B and 7.6.3.2.-C. (See Note A-7.6.3.2.(4))

(1)Each lavatory in a washroom with fixtures for public use shall be equipped with a device capable of automatically shutting off the flow of water when the lavatory is not in use. (See Note A-7.6.4.1.(1) and (3))

(2)An automatic compensating valve serving an individual shower head shall have a manufacturer's minimum-rated water flow rate equal to or less than the shower head it serves. (See Note A-7.6.4.1.(2))

(3)Where multiple shower heads installed in a public showering facility are served by one temperature control, each shower head shall be equipped with a device capable of automatically shutting off the flow of water when the shower head is not in use. (See Note A-7.6.4.1.(1) and (3))