A shutoff valve shall be provided in the main supply line inside of the buildings being served, except where one or more of the following conditions exist:
- The source and source valve are located inside the building served.
- The source system is physically mounted to the wall of the building served, and the pipeline enters the building in the immediate vicinity of the source valve. [NFPA 99:126.96.36.199.1]
The main line valve shall be located on the facility side of the source valve and outside of the source room, the enclosure , or where the main line first enters the building. [NFPA 99:188.8.131.52.2]