Scratches and Rubs
The inspector begins the inspection by standing at a distance of 160” from the glass surface. The inspector then moves closer to the glass surface, stopping at the point where the scratch or rub is first detected. If this distance is between 160” and 132” then it is cause for rejection. If the scratch or rub is visible when viewed between 132” and 40” and is over 3” long it is cause for rejection. If the scratch or rub is visible when viewed between 132” and 40” and it is less than 3” long, it is allowed as long as it is separated from a similar scratch or rub by at least 24”. If you need to be closer than 40” from the glass surface to view the scratch or rub, then it is allowed.
Bubbles, Pits, Knots, and Dirt
With the inspector standing at 39” from the glass surface, and the glass thickness is ¼” or less, bubbles, pits, knots, or dirt is allowed if the average of blemish’s length and width is 1/16” or less. Blemishes with an average length and width of 3/32” are allowed if they are separated from a similar blemish by at least 24”. Bubbles, pits, knots and dirt is not allowed if their average length and width exceeds 3/32.”
DEPTH- measuring from the face of the glass a chip is allowed if it’s depth does not exceed more than 50% of the glass thickness
WIDTH- measuring the perpendicular distance from the edge of the glass to the inner edge of the chip, a chip is allowed up to half of the glass thickness or ¼”, whichever is greater; for mirrors up to half of the mirror thickness or 1/16”, whichever is greater.
LENGTH- measuring parallel from the edge of the glass to the edge of a chip, a chip is allowed if its length does not exceed two times its width.