Interlaboratory Study (ILS) for F 548-01, The Standard Test Method for Intensity of Scratches on Aerospace Transparent Plastics

The American Society for Testing and Materials (ASTM) develops and publishes standardized test methods. Each test method requires a precision and bias statement so organizations that apply the method know its inherent reproducibility (between-laboratory variability) and repeatability (within-laboratory variability). Reproducibility and repeatability for this test method were determined by conducting an interlaboratory study (ILS) as outlined in ASTM E 691. This report, which conforms to the ILS reporting format required by ASTM, describes the study that was conducted for ASTM test standard F 548-01, Intensity of Scratches on Aerospace Transparent Plastics. Scratches exist on virtually all transparent plastic surfaces. Usually, cleaning procedures cause very fine scratches that are not visible when looking through the plastic. Visible scratches may be distracting to an observer looking through an aerospace transparent plastic. Therefore, a procedure to define scratches is useful. A visual comparison is made between a set of graded scratch standards (adjuncts) and a scratch on the plastic transparency to determine its relative intensity. A visual standard is used because it is not practical to measure the dimensions of the fine scratches.