Often open fire doors are generally installed in places with large flow of people, such as schools, large shopping malls, hospitals and other places. These places due to frequent access to the stairwell, if the installation of often closed fire doors must not be convenient. At the same time, if often open the fire door will lead to often closed fire door damage, so as not to play the role of fire prevention, the formation of fire hazards. Therefore these places are generally installed normally open fire doors. Often open fire doors in normal conditions in the open state, convenient for people to enter and exit. When there is a fire, it automatically shuts off by electrical control, and feedback the action signal. Often open fire door is not a simple fire door in the open state, must meet in the fire can automatically control the function of closing, so often open fire door must be set up fire alarm system with its matching.