由于闭口楼承板完全密合的闭口肋断面设计,其组合楼板提供一个均匀混凝土厚度的隔火屏障,当板底遭火延烧时，除了波谷平板部分因为直接曝火. 将被视为无效用钢以外, 其余被混凝土完全裏覆的板肋，它们的温度变化就如同现浇混凝土楼板里的钢筋在不同保护层厚度下的温度变化相似, 依然是相当称职的抵抗正弯矩钢筋, 因此闭口楼承板组合楼板的面1t火设计性能(无论是隔热性、完整性以及结构性)很明显地不是其它种板型 (开口型或缩口型) 组合楼板所能媲美 。
Due to the closed rib design, the BARD composite slab provides an uniform thermal insulation. Except the flat soffit, all the ribs are covered by the concrete and are not exposed to the fire, the final temperature of the ribs will be the same result as the re-bars placed at the same depth into the concrete slab, and still acting as a competent positive reinforcement. it is obvious that BARD is much superior to any other kinds of trapezoidal and/or re-entrant profiled steel sheets in the fire resistance.