Abstract: A valve for controlling flow of pressurized fluid from a confined area that is operable to relieve an overpressure condition as well as to allow flow of fluid in response to a pressure relief command. The valve including a valve body with a fluid passage therethrough, a reverse buckling rupture disc in the valve body in normally blocking relationship to the flow of fluid through the passage, and a selectively actuatable device carried by the valve body adjacent the convex surface. The actuatable device is operable to disrupt, without puncturing, the disc so as to initiate reversal and rupture of the disc and to permit flow of the pressurized fluid through the passage.