The following are the minimum backflow devices required to satisfy containment requirements and shall apply to those fire protection systems connected to the city water system (see AWWA M-14 and NFPA).
The director may require additional protection for the city water system if he deems it necessary due to potential contamination.
A. Class I: Direct connection from city water mains only; no pumps, tanks, or reservoirs; no physical connection from other water supplies; no antifreeze or other additives of any kind; all sprinkler drains discharging to atmosphere, dry wells, or other safe outlets.
B. Class II: Same as class I, except that booster pumps may be installed in the connections from the street mains (booster pumps do not affect the potability of the system; it is necessary, however, to avoid drafting so much water that pressure in the water main is reduced below 20 psi).
C. Device - class I and class II: No protection required with approval of the director.
D. Class III: Direct connection from city water supply main plus one or more of the following: elevated storage tanks; fire pumps taking suction from aboveground, covered reservoirs or tanks; and pressure tanks (all storage facilities are filled or connected to the city water only, the water in the tanks to be maintained in a potable condition).
E. Device - class III: Approved double check valve (DCV) installed as outlined in class I and class II.
F. Class IV: Directly supplied from city water mains similar to classes I and II, and with an auxiliary water supply on or available to the premises; or an auxiliary supply located within one thousand five hundred feet (1,500') of the pumper connection.
G. Device - class IV: Reduced pressure principle (RPP) device or double check valve (DCV); the valve shall be aboveground installation and as near the city water system as possible.
H. Class V: Directly supplied from city water mains, and interconnected with auxiliary supplies, such as: pumps taking suction from reservoirs exposed to contamination, or rivers and ponds; wells, mills or other industrial water systems; or where antifreeze or other additives are used.
I. Device - class V: Reduced pressure principle (RPP) device installed aboveground and as near the city water system as possible.
J. Class VI: Combined industrial and fire protection systems applied from the city water mains only, with or without gravity storage or pump suction tanks.
K. Device - class VI: Protection device would be determined after fire marshal and director had made a complete survey of the fire protection requirements of the premises. (Ord. 2009-02, 7-28-2009)