There are two types of Gas fire extinguishing system, one type is gas extinguishing control panel with fire alarm detector system and another is gas extinguishing control system only without fire detection system. The gas fire extinguishing system should be installed in library, computer and communication room etc. where the water extinguishing is not accepted. The gas fire extinguishing has two step to start fire extinguishing and it will be triggered by compound detectors alarm. And there are 3 types to start the fire extinguishing, automatically start, manually start and mechanically start.