D.C. Mun. Regs. tit. 12, r. 12-B2902
Strike Section P2902.5.4 of the International Residential Code in its entirety and insert new Section P2902.5.4 in the Residential Code in its place to read as follows:
Connections to automatic fire sprinkler systems. The potable water supply to automatic fire sprinkler systems shall be protected against backflow by one of the following methods:
Exception: Where systems are installed as a portion of the water distribution system in accordance with the requirements of this code and are not provided with a fire department connection, backflow protection for the water supply system shall not be required.
Strike Section P2902.5.4.1 of the International Residential Code in its entirety and insert new Section P2902.5.4.1 in the Residential Code in its place to read as follows:
Additives or nonpotable source. Where systems under continuous pressure contain chemical additives or antifreeze, or where systems are connected to a nonpotable secondary water supply, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly. Where chemical additives or antifreeze are added to only a portion of an automatic fire sprinkler system, the reduced pressure principle backflow prevention assembly or the reduced pressure principle fire protection backflow prevention assembly may be located so as to isolate that portion of the system. Where systems are not under continuous pressure, the potable water supply shall be protected against backflow by an air gap or an atmospheric vacuum breaker conforming to ASSE 1001 or CSA B64.1.1.
D.C. Mun. Regs. tit. 12, r. 12-B2902