An approved double-check detector backflow prevention assembly shall be the minimum protection on all new fire sprinkler systems using piping material that is not approved for potable water use, and/or that does not provide for periodic flow-through. A reduced pressure principle detector backflow prevention assembly must be installed, if any solution other than the potable water can be introduced into the sprinkler system.
Retrofitting fire sprinkler systems will be required in each of the following circumstances:
- Where improper maintenance has occurred.
- On all high-hazard systems.
- Wherever a CCS deems it necessary.
- Wherever required by the WAC.