Backflow preventers and vacuum breakers

1.1
The CSA B64 Series covers vacuum breakers and backflow preventers that are used in potable water supply systems to prevent cross-connections.

1.2
This Standard specifies definitions, general requirements, test methods, markings, and instructions that are common to some or all of the CSA B64 Series.

1.3
This Standard is not a complete Standard in itself and is intended to be used in conjunction with one of the Standards in the CSA B64 Series to form a complete Standard for a particular type of vacuum breaker or backflow preventer.

1.4
In CSA standards, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the standard.

Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.

Notes to tables and figures are considered part of the table or figure and may be written as requirements.

Annexes are designated normative (mandatory) or informative (nonmandatory) to define their application.

1.5
This Standard is written in SI (metric) units; for conversion tables, see Annex A. Vacuum is expressed in pressure below ambient. All pipe sizes are shown as nominal pipe sizes (NPS).