§ 25-134. Type of protection required.

The type of protection required shall depend on the degree of hazard which exists or may exist.

The degree of hazard, either high, moderate, or low, is based on the nature of the contaminant; the potential health hazard; the probability of the backflow occurrence; the method of backflow either by backpressure or by backsiphonage; and the potential effect on waterworks structures, equipment, and appurtenances used in the storage, collection, purification, treatment, and distribution of pure water.

Table 1 shall be used as a guide to determine the degree of hazard for any situation.

A.

An air gap or physical disconnection gives the highest degree of protection and shall be used whenever practical to do so in high hazard situations subject to backpressure.

B.

An air gap, physical disconnection and a reduced pressure principle backflow prevention device will protect against backpressure when operating properly.

C.

Pressure vacuum breakers will not protect against backpressure, but will protect against backsiphonage when operating properly. Pressure vacuum breakers may be used in low, moderate or high hazard situations subject to backsiphonage only.

D.

A double gate-double check valve assembly shall not be used in high hazard situations.

E.

Barometric loops are not acceptable.

F.

Interchangeable connections or changeover devices are not acceptable.

(Ord. No. 04-1700-769, § 1, 11-11-04)

(Ord. No. 04-1700-769, § 1, 11-11-04)