Notes to Table 7.5.8.4.:
7.6.2.4. Backflow from Fire Protection Systems (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. Table 7.6.2.4.   Backflow Preventers on Fire Sprinkler and Standpipe Systems Forming Part of Sentence 7.6.2.4.(2) Item   Column 1   Column 2   Column 3   Column 4   Column 5   Column 6 

      CSA Standard Number   Type of Device(1)   System Made with Potable Water System Materials   System Not Made with Potable Water System Materials 

              Minor Hazard(2) Residential Partial Flow-Through System   Minor Hazard(2) Class 1 System   Moderate Hazard(2) Class 1, 2, 3 and 6 Systems   Severe Hazard(2) – Any Class of System in which Antifreeze or Other Additives Are Used 

  1.   B64.6.1   DuCF   P   NP   NP   NP 

  2.   B64.9   SCVAF   P   P   NP   NP 

  3.   B64.5.1   DCVAF   P   P   P   NP 

  4.   B64.4.1   RPF   P   P   P   P