Building insulation materials weak and brittle. Before its risks were recognized, it was used because it was a cheap, effective insulator with a high R-value and its open-cell structure was a good acoustic insulator. Though it absorbed moisture easily, it regained effectiveness as an insulator when dried. Asbestos once found common use as an insulation material in homes and buildings because it is fireproof, a good thermal and electrical insulator, and resistant to chemical attack and wear. It has been found that asbestos can cause cancer when in friable form (that is, when likely to release fibers into the air - when broken,
Building insulation of building heat transfer - conduction, convection, and radiation. According to three ways of heat exchange，most thermal insulation we used in our building can be divided into two categories: Conductive and convective insulators and radiant heat barriers. And there are more detailed classifications to distinguish between different materials. Many thermal insulation materials work by creating tiny air cavity between molecules, this air cavity can largely reduce the heat exchange through the materials. But there are two exceptions which don’t use air cavity as their functional element to prevent heat transfer. One is reflective thermal insulation, which creates a great airspace