NAC455C.296. Safety and relief valves and indicating and controlling devices.

Each pressure vessel must be protected by safety or relief valves and indicating and controlling devices which will ensure its safe operation. These valves and devices must be so constructed, located and installed that they cannot readily be rendered inoperative. The relieving capacity of safety valves must be sufficient to prevent a rise of pressure in the vessel of more than 10 percent above the highest pressure to which any device to relieve pressure is set but in no case more than 6 percent above the maximum allowable working pressure. The opening pressure of the device to relieve pressure must not be greater than the maximum allowable working pressure of the vessel.

     (Added to NAC by Div. of Industrial Relations by R101-02, eff. 12-15-2004)