Any backflow prevention device required by this subchapter shall be of a model or construction approved by the city or its authorized representative and the State Department of Health.
(A) Air gap separation to be approved shall be at twice the diameter of the supply pipe measured vertically above the top rim of the vessel, but in no case less than one inch.
(B) Double check valve assemblies or reduced pressure principle backflow prevention devices shall appear on the current list of approved backflow prevention devices established by the State Department of Health, unless the device was installed at the time this subchapter was passed and complies with required inspection and maintenance.
(Prior Code, § 3-125)