Flat Glass Inspection Criteria per ASTM C 1036 – 11/ASTM C 1048-12


crush:lightly pitted condition with a dull gray appearance.

dig:deep, short scratch

gaseous inclusion:round or elongated bubble in the glass.

linear blemish: scratches, rubs, digs, and other similar imperfections.

point blemish: crush, knots, dirt, stones, gaseous inclusions, and other similar imperfections.

rub: abrasion of a glass surface producing a frosted appearance.

scratch:damage on a glass surface in the form of a line caused by the movement of an object across and in contact with the glass surface.


  • Visual inspection should be done with the naked eye
  • The inspector shall place the glass in a vertical position
  • Inspector shall view through the glass at an angle of 90ΒΊ
  • Lighting should be daylight level (without direct sunlight)

***View specimen from a distance of 6’***