In modern times, it is very important to ensure safety in the prevention, design, and maintenance of important facilities for fire protection. Fires occurring in important facilities such as industrial plants must be detected quickly, and the fire must be suppressed to minimize damage. For this purpose, it is necessary to accurately detect the fire and sound the fire alarm. To do this, it is very important to minimize the false alarm and improve the sensitivity of the fire detector. If devices are densely placed in a confined room, cables or switches with electrical contact are particularly vulnerable to fire. In this study, we evaluated a fire alarm and extinguishing system by considering the temperature profile during a cable fire in such a confined space. The fire detection algorithm and integrated management system developed in this study can be applied stably to the flame spreading fire because it can detect the fire faster than conventional detection systems. As compared with conventional smoke detectors, the delay time could be reduced by 20–30% for a fast-growing fire and by 30–60% for a smoldering fire.