Double detector check valve assemblies may be utilized in all installations requiring a double check valve assembly and detector metering. DDCs shall comply with the installation requirements applicable for double check valve assemblies (DCs).
Double Detector Check
Notes:
(1) Brass plugs to be installed in all test cocks.
(2) If domestic service is installed off the fire service, a second gate valve must be installed outside the vault. Joint restraint must be provided between this valve and the main.
(3) Strainer may be required. See standard detail no. 12.5-557.2.
Strainers
One of the most common causes of backflow prevention assembly failure is the accumulation of sand, scale or debris trapped in the assembly. This debris can cause the assembly to fail its required testing and can contribute to a shorter working life span of the assembly.
(Ord. 12274, § 1, passed 11-28-1995)