NABIC 256A Pipe Interrupter - Type DC (Permanent Vent) - Cat 5
The NABIC 256A is classified as a DC type suitable for protecting up to fluid category 5. The NABIC 256A incorporates ventilation ports that are totally unrestricted and permanent, water is guided past these air vents using a venturi type nozzle. Since they are constantly open to atmosphere this stops siphonage and allows the escape of water in the event of backflow. NABIC Valves now come with an Industry leading 5 Year Guarantee.
Flowstar, our parent company has an interesting article relating to Backflow Prevention in the Technical section on their website.
Sizes: 3/8" (DN10), 1/2" (DN15), 3/4" (DN20)
Connections: Male BSP Inlet x Male BSP Outlet
Materials: Brass body, Plastic internals, EPDM O-rings
Pressure: 10 Barg Max
Temperature: 60 degC Max
Note: The 1" is no-longer manufactured. The N-256A-015S is a low flow version of the standard N-256A-015