The Double Check Valve Device Assembly Shape and Sizes

The DCVA comes in a variety of sizes and shapes but they all function in the same manner. Size or shape does not have any relationship on the testing technique. The sizes range from ¼ inch to 12 inches.

Double Check Valve Backflow Prevention Device Assemblies Installed on Fire Protection Systems – Double Check Valve Detector Assemblies

The Double Check Valve Detector Assembly (DCDA) may be installed on fire protection systems to provide maximum protection against backflow and at the same time detect leakage or unauthorized use of fire sprinkler water. The DCDA is a double check valve backflow prevention device assembly with a bypass arrangement attached to the main assembly upstream of the first check valve and downstream of the second check valve. The bypass includes a water meter and a double check valve assembly. The double check valve assembly installed on the bypass is designed to require all flows of 2 GPM or less to pass through the bypass and be recorded on the water meter. The design specifications for a DCVAA are that the first check valve in the main assembly shall have a greater resistance than the first check valve in the bypass assembly. With this configuration, low flows of water will pass through the bypass as opposed to passing through the main assembly. The pressure loss through a DCDA is greater than the pressure loss through a DCVA. The DCVA on an average will reduce the pressure by 3 to 4 PSI; the DCDA will reduce the pressure by 7 to 8 PSI.