DOOR DEVICE FOR RELEASING PRESSURE

PROBLEM TO BE SOLVED: To ensure safety by opening an opening part for releasing pressure when gas filled in a structure exceeds a prescribed pressure, and to facilitate recovery work by recovering an attaching tool so as to close the opening for releasing pressure. SOLUTION: In the case where gas G in a structure 2 is low, a door body 4 holds a condition in which an opening part 3 for releasing pressure is closed by a pin 10. When the gas G is filled in the structure 2 and pressure is increased more than strength. of the pin 10, the pin 10 is cut, the door body 4 is lifted up, the opening part 3 for releasing pressure is opened, and the gas G is discharged outward. In compliance with reduction of pressure of the gas G, the door body 4 falls down while guiding each guided body 17 to a guide member 15, and the opening 3 for releasing pressure is closed. In the case where the door body 4 is fixed to the opening part 3 for releasing pressure, a new pin 10 is inserted into a pin inserting member 11, a fitting frame 8, and a pin supporting member material 12, and thereby, the door body 4 is easily fixed with low costs.