Reduced Pressure Principal Device is:

Reduced Pressure Principal Device is:

• A. A single valve that stops backflow.
• B. Two independent check valves with an automatic pressure differential valve between them.
• C. An air gap in the fill line.
• D. A device that vents air during low pressure.

Answer: (B)

A reduced pressure principle device is a backflow prevention assembly designed to stop both back pressure and back siphonage. It achieves this with two independently acting check valves and a pressure-differential relief valve between them. If pressure on the supply side drops or flow reverses, the relief valve opens and vents to the atmosphere, preventing any hazardous fluid from reaching the potable water supply. This setup provides high-level protection and is used where there is a risk from contaminants such as pesticides. The other options don’t fit: a single valve stopping backflow lacks the differential relief mechanism; an air gap is a passive separation method, not a valve assembly; and simply venting air during low pressure doesn’t describe the complete function of the RPZD.

A reduced pressure principle device is a backflow prevention assembly designed to stop both back pressure and back siphonage. It achieves this with two independently acting check valves and a pressure-differential relief valve between them. If pressure on the supply side drops or flow reverses, the relief valve opens and vents to the atmosphere, preventing any hazardous fluid from reaching the potable water supply. This setup provides high-level protection and is used where there is a risk from contaminants such as pesticides.

The other options don’t fit: a single valve stopping backflow lacks the differential relief mechanism; an air gap is a passive separation method, not a valve assembly; and simply venting air during low pressure doesn’t describe the complete function of the RPZD.