§ 64.59 — Spring Loaded Pressure Relief Valve

A spring loaded pressure relief valve must—

(a) Be set at a nominal pressure of 125 percent of the maximum allowable working pressure;

(b) Have a minimum normal venting capacity that is sufficient to prevent the tank pressure from exceeding 137.5 percent of the maximum allowable working pressure;

(c) Close after discharge of a pressure not lower than 115 percent of the maximum allowable working pressure; and

(d) If closed, remain closed at any pressure less than 115 percent of the maximum allowable working pressure.