Regulations of Connecticut State Agencies
Not less than fifty per cent of the sectionalizing valves which are sixteen inches or larger in nominal size shall be either continuously attended or shall be provided with automatic devices which close the valve in the event of a pipe line rupture. At large river crossings or other areas where the pipe line is exposed to extreme hazards, such automatic valves shall be installed at each side of the zone of hazard at the nearest accessible and safe point.