(1) Air gap separation to be approved shall be at least double the diameter of the supply pipe measured vertically above the flood level rim of the vessel, but in no case less than one inch.
(2) A double check valve assembly or a reduced pressure principle backflow prevention device shall be approved by the Municipal Water Department and shall appear on the current “list of approved backflow prevention devices” established by the Municipal Water Department.
(B) (1) Existing backflow prevention devices approved by the Municipal Water Department at the time of installation and properly maintained shall, except for inspection and maintenance requirements, be excluded from the requirements of §§
3-118 through 3-125
, so long as the Municipal Water Department is assured that they will satisfactorily protect the water system.
(2) Whenever the existing device is moved from its present location, or requires more than minimum maintenance, or when the Water Department finds that their maintenance constitutes a hazard to health, the unit shall be replaced by a backflow prevention device meeting the requirement of §§
3-118 through 3-125
.
(Ord. 448, passed 10-6-1992)