The present invention presents a novel alternative to side-hinged swinging doors that offers access to a broad egress opening width needed to meet higher occupancy egress requirements while simultaneously qualifying as a fire/smoke barrier. In a preferred embodiment, a single overhead coiling fire door shaft assembly is counter-balanced to allow a fire door curtain to automatically close at a governed controlled descent upon reaching an established critical low battery condition. An operator is provided that will run the door under both normal condition and during a power failure or fire/smoke condition at an established average door speed, and also provide established levels of low battery warning signals/actions while also providing the ability to open as required for emergency egress until the temperature at the opening is not conducive for human life.