(A) Lawn sprinkler systems shall be equipped with an approved pressure-type vacuum breaker, which meets A.N.S.I. Standard No. 1020, on the discharge side of the last valve. The vacuum breaker shall be installed no less than 12 inches above the highest head and no less than 12 inches above the surrounding ground. Where combination control valves and backflow preventers are installed, the bottom of the valve shall constitute the bottom of the backflow preventer; and when area controls are installed, a vacuum breaker may be installed on the discharge side of the main control providing not less than one head shall be controlled exclusively by the main control valve.
(B) All installations other than single-family dwellings are to have a reduced principal backflow preventer assembly approved by the building official and by the Metropolitan Utilities District.
(C) All pressure vacuum breakers must be installed outside.
(D) A reduced pressure backflow preventer assembly can be installed inside a building if approved drainage is provided.
(E) If a master valve is installed inside a building, it should be of a brass material operated by a 24-volt solenoid.
(F) Copper pipe shall be run from the discharge side of a backflow preventer to approximately three inches below grade.
(G) Under no circumstances can an atmospheric vacuum breaker be used on a pressurized main line.
(H) If a pressure vacuum breaker must be mounted more than four feet above the grade due to higher elevation in the surrounding grade, then an ASSE approved dual check valve shall be installed on the service side of the PVB, to be mounted less than four feet above the grade.
(I) Any sprinkler system on which a chemical or fertilizer injection system has been installed must have a reduced pressure principal backflow preventer assembly installed according to this Code.
(Ord. 2867, § 1, passed 12-11-1995)