| 摘要 |
PROBLEM TO BE SOLVED: To provide a vent port edge material excellent in fireproofing, and a vent port which is automatically closed upon firing. SOLUTION: A shielding plate 4 is mounted at a position behind a vent port 2 of a break line edge member 1 at a prescribed interval in a cantilevered state. A refractory heating/expansion member 6 is mounted on the tip end of the shielding plate 4, and on the occurrence of a fire an air passage is shielded by making use of expansion of the heating expansion member 6.
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