Before Asbestos abatement using different methods is performed, it must first be clarified whether or not Asbestos materials are present. This trivial question represents a frequent problem in the practice of investigating old sites. Since in the developing countries specialized laboratories for definite microscopic determination of Asbestos fibers are not available in some cases, it is recommendable to analyze the building materials used. In Annex 5, examples of different Asbestos containing building materials are listed.

A visual investigation of the applied building materials by trained personnel is recommended as a first survey of potential Asbestos containing materials. Particular attention should be paid to fibrous and easily breakable building materials. The main application areas for Asbestos containing materials (see Part II Chapter 4) should be particularly investigated during the visual inspection.

Identification of the particularly hazardous sprayed Asbestos can also be performed visually to some extent: "Sprayed Asbestos is a white-gray, gray or gray-blue typically soft material which can be indented by the finger. The surface is typically scarred, even if it is protected with laitance or paint." (UBA-Report 5/91).