Systems & CodeQuestion 40 of 110
A reduced-pressure principle (RP) backflow assembly is installed on a service subject to a health hazard. How must it be installed with respect to the ground and drainage?
a.Below grade in a valve box
b.Flush to a wall with the relief plugged
c.Any orientation as long as it is accessible
d.Above grade with the relief port able to discharge to atmosphere
Explanation
An RP assembly must be installed above grade with an air gap below its relief port so the relief can discharge freely and be observed; it may not be submerged in a pit that could flood the relief. RP assemblies protect against both backsiphonage and backpressure of high-hazard (health) cross connections. Submerging or plugging the relief defeats the protection.
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