FIRE RESISTING PROPERTIES OF COMMON BUILDING MTERIALS

下面提到了石材，砖，木材，铸铁，玻璃，钢和混凝土等共同建筑材料的耐火性能。新利客户

1.石头

The stone is a bad conductor of heat. But it suffers appreciably under the effects of fire. The stone is also liable to disintegrate into small pieces when heated and suddenly cooled. Granite explodes and gets easily disintegrated in case of a fire. Limestone is easily crumbled even by ordinary fire. Sandstones of compact composition with fine grains can generally stand moderate fire successfully without the formation of serious cracks.

2.BRICKS

结果发现，砖块不会受到严重影响，直到1200的高温⁰C到1300.⁰C are reached. This is due to the fact that a brick is a poor conductor of heat. If the type of mortar and quality of workmanship are good, brick masonry generally offers good resistance to fire. However, a brick has its own structural limitation for use in buildings.

3.TIMBER

作为一般规则，在燃烧时由木材点燃并迅速摧毁结构元素。此外，它们增加了火的强度。但是，在重型部分中使用的木材可以达到高度的防火，因为木材是一种非常糟糕的热量。这就是为什么时间是建立足够的热量的时间，以便在木材中引起火焰。为了使木材更耐火，木材表面有时涂有磷酸铵和硫酸铵，硼砂和硼酸，氯化锌等的某些化学物质。这种处理在木材表面上延迟了火灾期间的温度升高。木材凸轮也通过在其表面上的某些涂料的应用来耐火。

4.铸铁

This material is rarely used as structural material at present. This material flies into pieces when heated and suddenly cooled. Hence, when this material is used in construction, it is covered either by brickwork of one brick thickness or any other fire resisting material such as concrete.

5.GLASS

This material is a poor conductor of heat and its expansion due to heat is small. Cracks are formed I this material when heated and then suddenly cooled. Reinforced glass with steel wire is ore fire-resistant than ordinary glass and it can resist sudden variation in temperature without the formation of cracks. Wired glass, even if it breaks, keeps the fractured glass in its original position.

6。STEEL

Steel is a good conductor of heat and hence, it is rapidly heated in case of fire. It is found that steel loses its tensile strength with the increase in heat and the yield stress of mild steel at 600⁰C is about one-third of its value at normal temperature. Hence, under intense fire, the unprotected steel beams sag, the unprotected steel columns buckle and the structure collapses. Steel completely melts at a temperature of 1400⁰C. It is also found that if the surface paint is not specially made fire-resistant, it assists in spreading the flame on the surface and thereby it adds to the intensity of fire.

If steel plate or sheet form is fixed to framework, it becomes affective is resisting the passage of flame. Such construction is widely adopted in manufacturing fire-resisting doors and windows.

7。CONCRETE

混凝土具有非常好的防火。在火灾情况下具体的实际行为取决于所用水泥和聚集体的质量。在钢筋混凝土和预应力混凝土的情况下，它还取决于钢的位置。较大的混凝土罩，更好的是构件的耐火性。
There is no loss in strength in concrete when it is heated up to 250°C. The reduction in strength starts if the temperature goes beyond 250°C. Normally reinforced concrete structures can resist fire for about one hour at a temperature of 1000°C. Hence cement concrete is ideally used fire resistant material.

还读:Fire Protection Requirements for Multistoreyed Buildings