Abstract: An adapter bracket that can be attached to the exterior of a conventional gate valve and valve actuator converting the valve to a fire safety valve. The bracket can be clamped to the exterior of the valve/actuator housing without modification to the existing structure. The bracket includes an adapter plate with an externally threaded cylindrical extension. A hole through the adapter plate is coaxial with the aperture through the cylindrical extension to non-engagingly permit the valve actuator rod to pass therethrough. The threaded extension receives a standard lock-open cap to hold the valve in the open position to avoid severing of the cable in wireline operations due to a power outage, for example. The cap includes a portion made of fusible material which, in the event of fire, will melt permitting the valve to close under operation of a biasing spring.