In addition to the requirements of § 50.124, the following shall also apply:
(A) Fire protection systems consist of sprinklers, hose connections, and hydrants. Sprinkler systems may be dry or wet, open or closed. Systems of fixed-spray nozzles may be used indoor or outdoors for protection of flammable liquid and other hazardous processes. It is standard practice, especially in cities, to equip automatic sprinkler system with Fire Department pumper connections.
(1) A meter (compound, detector check) should not normally be permitted as part of a backflow prevention assembly. An exception may be made, however, if the meter and backflow prevention assembly are specifically designed for that purpose.
(2) For cross-connection control, fire protection systems shall be classified on the basis of water source and arrangement of supplies as follows:
(a) Class 1 - Direct connections from public 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. For minimum protection, see § 50.124;
(b) Class 2 - Same as Class 1, 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. For minimum protection, see § 50.124;
(c) Class 3 - Direct connection from public water supply main plus one or more of the following: elevated storage tanks, fire pumps taking suction from above-ground covered reservoirs, or tanks; and pressure tanks (all storage facilities are filled or connected to public water only, the water in the tanks to be maintained in a potable condition). Otherwise, Class 3 systems are the same as Class 1. Class 3 systems will generally require minimum protection (approved double-check valves) to prevent stagnant waters from backflowing into the public potable-water system;
(d) Class 4 - Directly supplies from public mains similar to Classes 1 and 2, and with an auxiliary water supply on or available to the premises; or an auxiliary supply may be located within 1,700 feet of the pumper connection. Class 4 systems will normally require backflow protection at the service connection. The type (air gap or reduced pressure) will generally depend on the quality of the auxiliary supply;
(e) Class 5 - Directly supplies from public mains, and interconnect with auxiliary supplies, such as: pumps taking suction from reservoirs exposed to contamination, or rivers and ponds, driven wells, mills, or other industrial water system; or where anti-freeze or other additives are used. Class 4 and 5 systems normally would need maximum protection (air gap or reduced pressure) to protect the public potable water system; and
(f) Class 6 - Combined industrial and fire protection systems supplied from the public water mains only, with or without gravity storage or pump suction tanks. Class 6 system protection would depend on the requirements of both industry and fire protection, and could only be determined by a survey of the premises.
(B) When a backflow prevention assembly is required for a water service connection supplying water only to a fire system, the assembly shall be installed on the service line in compliance with standard specifications adopted by the City of El Mirage. (Installation of DCVA’s or DDCVA’s in a vertical position on the riser may be allowed on fire systems with the Department’s approval.)
(Prior Code, § 14-10-7)