Page 104 - Microsoft Word -Cow Book 10-06-09 final update.doc

III. PRESSURE TYPE - Reduced Pressure Zone is allowed in all applications.
It cannot be installed where it may become submerged,
and it protects against both back-pressure back-flow
and back-siphonage back-flow. It can be used in
constant or intermittent pressure applications, and high
and low hazard applications.

Reduced Pressure Zone (RP)
 High hazard
 Back pressure / Back siphonage
 Continuous pressure – can have valves down stream
 Bottom must be > 12 above grade
 Cannot be installed in a pit
 Relief valve must be indirectly plumbed
 Installed horizontally unless approved
 Check annually, at installation & when taken in /out/ of service
 High pressure chemical washer
 Boilers

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