7.6.2.3 — Protection from Backflow

(1) Except as provided in Sentence (2), back-siphonage preventers and backflow preventers shall be certified to, (a) CSA B64.0, “Definitions, General Requirements and Test Methods for Vacuum Breakers and Backflow Preventers”, (b) CSA B64.1.1, “Atmospheric Vacuum Breakers (AVB)”, (c) CSA B64.1.2, “Pressure Vacuum Breakers (PVB)”, (d) CSA B64.1.3, “Spill-resistant Pressure Vacuum Breakers (SRPVB)”, (e) CSA B64.1.4, “Vacuum Breaker, Air Space Type (ASVB)”, (f) CSA B64.2, “Hose Connection Vacuum Breakers (HCVB)”, (g) CSA B64.2.1, “Hose Connection Vacuum Breakers (HCVB) with Manual Draining Feature”, (h) CSA B64.2.1.1, “Hose Connection Dual Check Vacuum Breakers (HCDVB)”, (i )CSA B64.2.2, “Hose Connection Vacuum Breakers (HCVB) with Automatic Draining Feature”, (j) CSA B64.3, “Dual Check Valve Backflow Preventers with Atmospheric Port (DCAP)”, (k) CSA B64.3.1, “Dual Check Valve Backflow Preventers with Atmospheric Port for Carbonators (DCAPC)”, (l) CSA B64.4, “Reduced Pressure Principle (RP) Backflow Preventers”, (m) CSA B64.5, “Double Check Valve (DCVA) Backflow Preventers”, (n) CSA B64.6, “Dual Check Valve (DuC) Backflow Preventers”, (o) CSA B64.7, “Laboratory Faucet Vacuum Breakers (LFVB)”, (p) CSA B64.8, “Dual Check Valve Backflow Preventers with Intermediate Vent (DuCV)”, or (q) CSA B64.10, “Selection and Installation of Backflow Preventers”. (2) Back-siphonage preventers (anti-siphon fill valves) for tank type water closets shall be certified to CSA B125.3, “Plumbing Fittings”.

(1) A backflow preventer shall not be required in a residential full flow through fire sprinkler system, in which the pipe and fittings are constructed of potable water system materials. (2) Except as required in 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 the following Clauses: (a) Residential partial flow through fire sprinkler 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 CSA B64.6.1, “Dual Check Valve Backflow Preventers for Fire Protection Systems (DuCF)”, (b) Class 1 fire sprinkler/standpipe systems shall be protected by a single check valve backflow preventer conforming to CSA B64.9, “Single Check Valve Backflow Preventers for Fire Protection Systems (SCVAF)”, provided that the systems do not use antifreeze or other additives of any kind and all pipes and fittings are constructed of potable water system materials, (c) 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 CSA B64.5.1, “Double Check Valve Backflow Preventers for Fire Protection Systems (DCVAF)”, provided that the systems do not use antifreeze or other additives of any kind, (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 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 CSA B64.4.1, “Reduced Pressure Principle Backflow Preventers for Fire Protection Systems (RPF)”, (f) Class 6 fire sprinkler/standpipe systems shall be protected, (i) by a double check valve backflow preventer conforming to CSA B64.5.1, “Double Check Valve Backflow Preventers for Fire Protection Systems (DCVAF)”, or (ii) where a severe hazard may be caused by backflow, by a reduced pressure principle backflow preventer conforming to CSA B64.4.1, “Reduced Pressure Principle Backflow Preventers for Fire Protection Systems (RPF)”, and (g) backflow preventers on fire sprinkler and standpipe systems shall be selected and installed in conformance with Table 7.6.2.4. (3) The backflow preventer 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 the water service pipe at a service connection located on the same premises as the fire service main 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 provided on the fire service connection.

(1) Except as permitted by Sentence (2) and as provided in Sentences (3) and (4), a potable water system shall be protected against backflow where the heat transfer loop of a solar domestic hot water system is directly connected to the potable water system. (2) Where the heat transfer loop of the solar domestic hot water system consists of direct flow-through of potable water only, protection against backflow is not required. (3) A potable water system that is directly connected to the heat transfer loop of a solar domestic hot water system that serves a residential occupancy within the scope of Part 9 shall be provided with a backflow preventer selected in accordance with CAN/CSA-F379.1, “Packaged Solar Domestic Hot Water Systems (Liquid-to-Liquid Heat Transfer) for All-Season Use”. (4) Where a solar domestic hot water system includes a single wall heat exchanger and contains only a relatively harmless heat transfer fluid as described in CAN/CSA-F379.1, “Packaged Solar Domestic Hot Water Systems (Liquid-to-Liquid Heat Transfer) for All-Season Use”, the backflow prevention required in Sentence (1) is permitted to be a dual check valve backflow preventer conforming to CSA B64.3, “Dual Check Valve Backflow Preventers with Atmospheric Port (DCAP)”.

(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”.