本研究主要在探討斷面尺度因子(W/D)對被覆鋼骨構件耐火緎能之影響，試驗中以不同斷面尺度因子之H型鋼樑，四面噴附M1、M2兩種耐火被覆材料，待試體水份蒸發至衡重後，進行耐火試驗以CNS 12514規之建築物火災標準升溫曲線作為加熱條件，探討斷面尺度因子與被覆厚度及耐火時效之關係。 試驗結果顯示：在A尺度耐火試驗上，相同被覆材料及被覆厚度下，鋼樑之耐火時效對劭斷面尺度因子的增加而延長；但是耐火時效和使覆厚度之比值(t/T)與斷面尺度因子(W/D)之關係，會因被覆厚度不同而迴歸成兩條直線；且斜率及截距，會因被覆材料不同而改變。

　　　　　The paper is to study the effect of section scale factor for coating steel structure fireproof capacity. Using different H shape steel beams of section scale factor in test, and painted around M1, M2 two frieproof coating materials, after water evaporable of specimen to counterweight and proceed fire resisting test. Using the building fire standard rising temperature curve under CNS 12514 to be heated condition, and study the relationship of section scale factor, coating thickness and fireproof duration. The test result detect: In the same covering material and thickness, the steel beam fireproof duration will lengthen caused by section scale factor under A scale fireproof test; the relationship between t/T of freproof duration with covering thickness and section scale factor will regression change to two parallel by differ covering thickness. The slope of line and its intercept will changed by differ covering material.