Page 104 - Microsoft Word -Cow Book 10-06-09 final update.doc
P. 104
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
94