scope:

Description

This standard applies to two types of backflow prevention assemblies identified as a (Double Check Backflow Prevention Assembly (DC) and a Double Check Fire Protection Backflow Prevention Assembly (DCF). These assemblies consist of two (2) independently acting check valves, internally force loaded to a normally closed position, two (2) tightly closing shut-off (isolation) valves, and properly located test cocks. These assemblies are designed and constructed to operate under intermittent or continuous pressure conditions.

This standard also applies to Manifold Double Check Backflow Prevention Assemblies. These consist of two or more complete Double Check Backflow Prevention Assemblies in parallel. The assemblies do not need to be of the same pipe size. The manifold size shall be identified by the single inlet and outlet of the manifold device. It shall consist of shut-off valves on the inlet and outlet of each of the assemblies in the manifold and the shut-off valves shall be line sized to each backflow assembly in the manifold.

Size Range

Connection pipe sizes shall be in accordance with Table 1.

Pressure Range

A DC assembly shall be designed for a working pressure of at least 150.0 psi (1034.3 kPa).

A DCF assembly shall be designed for a working pressure of at least 175.0 psi (1206.7 kPa).

Temperature Range

(a) Assemblies designed to be installed in cold water lines only shall be designed for flow temperatures of at least 33.0 °F to 140.0 °F (0.6 °C to 60.0 °C).

(b) Assemblies designed to be installed in cold or hot water lines only shall be designed for flow temperatures of at least 33.0 °F to 180.0 °F (0.6 °C to 82.2 °C).