scope:

Vacuum breakers and backflow preventers covered by the CAN/CSA-B64 Series of Standards include only those devices that are designed for use in potable water supply systems to prevent cross-connections. 

This Standard covers definitions, general requirements, test methods, marking, and instructions that arc common to some or all of the CAN/CSA-B64 Series of Standards.  

This is not a complete Standard in itself and must be used In conjunction with one of the other Standards in the CAN/CSA-B64 Series to form a complete Standard for a particular type of vacuum breaker or backflow preventer. 

Notes to the text do not include mandatory or alternative requirements. The purpose of a note is to separate from the text explanatory or informative material that is not properly a part of the Standard. Notes to figures and tables are to be considered part of the figure or table and are written as mandatory requirements. Legends to figures are to be considered mandatory requirements. 

This Standard Is written in SI (metric); for conversion tables, see Appendix A of this Standard. Vacuum Is expressed In pressure below ambient.