Interlaboratory study (ILS) for F 428-83, the standard test method for intensity of scratches on aerospace glass enclosures

Scratches exist on all glass surfaces. Usually cleaning procedures cause very fine scratches that are not visible when looking through the glass. Visible scratches may be distracting to an observer looking through a transparent aerospace enclosure. Therefore, a procedure to define scratches is useful. A visual comparison is made between a set of graded scratch standards and a scratch on the glass transparency to determine its relative intensity. A visual standard is used because it is not practical to measure the dimensions of the fine scratches.