- DESIGN ASSISTANCE
Stand 10 feet away from the glass.
Face the glass straight on at 90 degrees.
View the glass in daylight, not direct sunlight.
Inspect 80% of the central portion of the glass.
Inspection should not exceed viewing of more than the following in transmission or reflection.
Under these conditions, if you cannot see the defect from 10 feet away, the ASTM standard states it is not a defect. If defects are visible beyond what is allowable as listed above, the glass maybe rejected. Defects include scratches, seeds, bubbles, debris, stones, shells, chips and spots.
ASTM International is the basis for understanding glass and coating quality, allowable defects, and visual inspection criteria. ASTM has many different specifications and classifications depending on the type of glass being analyzed or quality controlled. Some examples of coating quality criteria are:
ASTM C 1036-16 (Standard specification for flat glass) Q3 / Glazing select specifications or better
ASTM C 1048-92 (Standard specification for heat-treated glass – kind HS, kind FT coated and uncoated glass) specifications using Q3 quality or better
ASTM C 1376-97 (standard specification for Pyrolytic and vacuum deposition coatings on glass) kind CV specifications or better