At a new condominium complex, numerous windows were discovered to have been damaged by weld spatter. Upper left is a photograph of typical damage found on the affected windows. A glass expert examined the damage to determine if the windows could be repaired. A glass failure analysis was performed to evaluate the damage level. Microscopic examination showed that the damage was below the surface. The damage depth varied from 0.05 mm to 0.3 mm deep. The photo on the upper right is a 20X photomicrograph of the glass damage. The round part of damage is 0.3 mm deep. The failure analysis expert deems these windows unrepairable. They must be replaced.