limit of fire resistance

• 耐火极限

limit of fire resistance的用法和样例：

例句

1. The coatings film will be dilatated when contacted to fire, forming a high dense and microporous fire proofing layer to prolong the fire retardant limit of steel structures.
   由该涂料制得的涂层遇火发泡膨胀，形成具有一定厚度的密实微孔状阻燃层，从而提高了钢结构的耐火极限。