Abstract: A coupling includes plug and socket assemblies which are interconnectable to connect conduits in fluid communication. A heat fusible actuator member is connected with a valve member disposed in the socket assembly. The actuator member extends axially outwardly from the valve member and has an outer end portion which is engageable with the plug assembly to move the valve member from a closed condition to an open condition as the plug and socket assemblies are interconnected. The actuator member is fusible upon exposure to excessive heat to release the valve member for movement from the open condition to the closed condition under the influence of a biasing spring. As the valve member moves from the open condition to the closed condition, the size of the actuator member is reduced as it is compressed into a unitary body under the influence of the force applied against the valve member by the biasing spring.