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 code also requires insulation for floors (not all floors). Raised timber floors must have around 400mm soil clearance below the lowest timbers to provide sufficient space for insulation, and concrete slab such as suspended slabs and slab-on-ground should be insulated in the same way. China has various climatic characters, which are divided by geographical areas. As a result, there are five climate zones in China to identify the building design include thermal insulation. (The very cold zone, cold zone, hot summer and cold winter zone, hot summer and warm winter zone and cold winter zone). There is no certain indoor