15-23-9 Installation of Backflow Prevention Assemblies for Fire Systems.
A. Fire protection systems may consist of sprinklers, hose connections, and hydrants. Sprinkler systems may be dry or wet, open or closed. Systems consisting of fixed-spray nozzles may be used indoors or outdoors for protection of flammable liquid and other hazardous processes. It is standard practice, especially in cities, to equip automatic sprinkler systems with fire department pumper connections.
B. For cross-connection control, fire protection systems shall be classified on the basis of water source and arrangement of supplies as follows:
1. 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.
2. Class 2: Same as class 1, except that booster pumps may be installed in the connections from the street mains. It is necessary to avoid drafting so much water that pressure in the water main is reduced below twenty (20) PSI.
3. Class 3: Direct connection from public water supply main plus one (1) 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 1, 2, and 3 systems will generally require minimum protection (approved DC or DCDA) to prevent stagnant waters from backflowing into the public potable water system.
4. Class 4: Directly supplied 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 seventeen hundred feet (1,700') of the pumper connection. Class 4 systems will normally require backflow protection at the service connection. The type (AG, RPA or RPDA) will generally depend on the quality of the auxiliary supply.
5. Class 5: Directly supplied from public mains, and interconnected with auxiliary supplies, such as: pumps taking suction from reservoirs exposed to contamination, or rivers and ponds; driven wells, mills or other industrial water systems; or where antifreeze or other additives are used. Class 5 systems normally would need maximum protection (AG, RPA or RPDA) to protect the public water system.
6. 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 shall be determined by the Utility through a survey of the premises.
C. Installation of Assembly. 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 Town.
1. Pressure losses across backflow prevention assemblies must be accommodated in the hydraulic design or redesign of the automatic fire sprinkler system.
2. Backflow prevention assemblies shall be installed above ground and as close to the service connection as possible on private property. When an assembly is installed in a mechanical room, sufficient drainage and space must be provided for the testing and maintenance of the backflow prevention assembly.
3. Installations shall meet current plumbing and fire codes as applicable in addition to the Utility’s standard details.
4. Backflow prevention assemblies shall be installed in a horizontal or vertical position in accordance with their listing.
5. A forty-five (45) day installation permit is required for all backflow prevention assemblies. In addition, the installation must be inspected by the Utility and the assembly must be tested by a state certified backflow prevention tester before approval. The fire line contractor should make arrangements with a private backflow prevention assembly tester that is registered with the Utility. A certified backflow prevention tester will only have responsibility for the test and repair of the backflow prevention assembly and not any other component of the automatic fire sprinkler system unless that person is certified to perform testing on fire sprinkler systems.
6. Backflow prevention assemblies will be UL 1469 listed. ((O)07-21, 03/21/2007; (O)98-03, 01/07/1998. Formerly 15-23-7)