Abstract: A valve assembly includes a valve body having a fluid chamber and a fluid inlet and fluid outlet. A poppet assembly is movably disposed within the chamber and includes a poppet head. The chamber includes a valve seat and is interposed between the fluid inlet and outlet. An actuator is attached to the poppet assembly. A lock-out mechanism is connected with the actuator for placing the valve into a closed position with the poppet head positioned against the valve seat. The lock-out mechanism includes a shaft member that is movably attached to the valve apparatus. When the shaft member is in a first position, the actuator is permitted to cause desired poppet assembly movement with the valve. When the shaft member is in a second position, the actuator and poppet assembly position within the valve is fixed with the poppet head seated against the valve seat.