scope:

This Standard provides requirements for the selection and installation of backflow prevention devices. Additional information on how backflow due to back siphonage and back pressure occurs, and on the selection and application of specific devices, is included in Appendices A, B, and C.

This Standard does not include requirements for materials, construction, or performance tests of backflow preventers. Such requirements for the majority of the devices are provided in the B64 Series and CSA Standard B125 (see Table 1).

This Standard does not include requirements for maintenance or field testing after the initial installation. These requirements are covered in CSA Standard B64.10.1.

In this Standard, "shall" is used to express a requirement, ¡.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. Legends to equations and figures are considered requirements.

This Standard is written in SI (metric) units; for conversion tables, see Appendix D. Vacuum is expressed in pressure below ambient.