California Failure Analysis Expert Witness performs a glass failure analysis on defective tempered glass windows installed in a public building. One of the construction defects was window scratching. Representative windows were removed and sent to the Read Consulting California failure analysis lab. This allowed a detailed investigation of the window defects. The failure analysis determined that the scratches were caused by post construction cleaning. Upper left is a macrophotograph of a typical set of scratches. Their parallel nature shows them to have been caused by a metal scraper. Upper right is a 40X photomicrograph of a scratched region. These scratches were in the glass. There was no coating on the scratched surface.