To suppress the generation of clinker so as to prevent the generation of a burning trouble, ceramic particles 30 are covered over a porous plate 4 to form a fire bed 3. Prior to deployment, the airbag is compacted in the storage condition. Upon comparison of the fixed and rolling codes with stored codes and determining that the signal has emanated from an authorized transmitter, a signal is generated to actuate an electric motor to open or close a movable barrier.