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Inspecting Glass for Quality Issues

  • All visual inspections shall be made with 20/20 vision.

  • View glass at 90° in daylight, but not direct sunlight.

  • Stand at distance as specified by type of defect, focusing on the central area (center 80% of length and width) while looking through the glass and not directly at the surface. 

  • For chips: View chips from 1' away without magnification, using localized lighting.

How to visually inspect glass for blemish detection
area of glass that needs to be reviewed for blemish detection

Visual Standards - Bowing

  • Use a "true straight edge, wire, string or monofilament fishing line."

  • Measure each of the 4 sides for overall bow on the concave portion of the glass within 1" of the glass edge and parallel to the edge.

  • Also check the approximate horizontal and vertical centerlines for overall bow. 

how to measure bowing on tempered glass
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