The RD Retarding Chamber is used with the Alarm Valve Trim when variable pressure is anticipated in the system. It is a holding tank to prevent the sounding of the sprinkler alarm during a water pressure surge, but will permit the sounding of the alarm on a sustained flow.
The retarding chamber is connected to the alarm port of the alarm valve through the restriction nozzle. The retarding chamber is part of UL Listed Alarm Valve Trim. The retarding chamber is made of Cast Iron material.