BS EN 17020-1:2022 防火和/或防煙門和可開啟窗戶自關閉耐久性測試結果的擴展應用 鉸鏈和樞軸鋼門自關閉耐久性
Extended application of test results on durability of self-closing for fire resistance and/or smoke control doorsets and openable windows - Durability of self-closing of hinged and pivoted steel doorsets