Abstract: A safety valve for releasing excessive fluid pressure from a pressure vessel including a valve body having an inlet and an outlet, a seat bushing connected into the inlet defining an inlet flow passage, a valve seat on the inward end of the seat bushing, a valve disc having a seat thereon movably mounted in the valve body for opening and closing the valve, a spring coupled with the valve disc for biasing the valve disc toward a closed position. The valve disc includes a convex end portion to reduce turbulence during flow into the valve to permit improved seating of the valve disc and an external annular recess defining an annular lip on the valve disc including a seat having a frustoconical seat surface, the lip being flexible to improve the disc seat contact with the seat around the valve inlet to increase the seat tightness of the valve.