Asbestos - Homogeneous Materials

Material classification 

There are three main kinds of material according to EPA sampling guidelines. They are Surfacing Material, Thermal system Insulation, and Miscellaneous material. The classification bears implications for number of samples to be taken. For Surfacing material, there's the 3-5-7 rule, meaning 3 samples from less than 1,000 square feet area, 5 samples from 1,000 to 5,000 square feet area, and 7 samples from greater than 5,000 square feet area. For Thermal system material, with some exceptions, 3 samples should be taken for each homogeneous area. For Miscellaneous material, at least one sample should be taken from each homogeneous material. 

Recognition of Homogeneous Areas 

Homogeneous material means an area of surfacing material, thermal system insulation material or miscellaneous material that is uniform in color and texture. It should be pointed out that materials appear to be homogeneous and adjacent to each other may in fact have different contents in terms of asbestos, and only laboratory testing will decide whether they are really the same homogeneous area. 

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