A valve body, having a lateral exhaust port, is provided with a valve movable toward and away from a fluid inlet sealing face at its pressure connected end and guided by a valve stem projecting through the other end of the body. A plurality of rupture bands, extending transversely across the outwardly projecting end of the valve stem, are connected with the body for normally maintaining the valve closed. Excessive fluid pressure against the valve ruptures the bands and releases pressure through the lateral port.