ASTM F428-09(2014)

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Designation: F428 − 09 F428 − 09 (Reapproved 2014)
Standard Test Method for
Intensity of Scratches on Aerospace Glass Enclosures
This standard is issued under the fixed designation F428; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the visual inspection of scratches on the glass surface of aerospace transparent enclosures.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all
of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate
safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 Other Standards:
Glass Scratch Visual Comparison Standard
3. Summary of Test Method
3.1 A visual comparison is made between a set of graded scratch standards and the scratch on the glass aerospace transparency
to determine the relative intensity of the scratch.
4. Significance and Use
4.1 Scratches exist on all glass surfaces. Often there are very fine scratches from cleaning operations that are not visible when
looking through the glass. Visible scratches may be distracting to the observer looking through the transparency. Therefore, a
procedure to define the severity scratches is useful. A visual standard is used because it is not practical to measure the dimensions
of the fine scratches in the scope of this test method.
5. Reference Materials
5.1 Glass Scratch Visual Comparison Standard consists of a set of six hermetically sealed glass plates 38 mm square with
scratches of graded intensity on the inside surface. The lightest scratch is identified as ASTM F428-3 and the heaviest as ASTM
F428-8.
6. Procedure
6.1 Place the part in a suitable inspection position. This may be horizontal on a padded table, vertical against a neutral to dark
background, or at an angle simulating the installed position. The scratched surface shall be toward the observer. The light level
shall be a minimum of 80 lux. Either natural or artificial light may be used. If possible, move the light until the scratch has the
highest contrast against the background. Place the scratch in the visual comparison standard beside and parallel to the scratch in
question. Rotate the part or viewing angle to get the best definition of the scratch. Disregarding the length of the scratch on the
part and on the standard, select and record the standard that most closely matches the appearance of the scratch on the part.
Measure and record the length of the scratch to the nearest 1 mm.
This test method is under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 on Transparent
Enclosures and Materials.
Current edition approved May 15, 2009Dec. 1, 2014. Published June 2009December 2014. Originally published in 1977. Last previous edition approved in 20032009 as
F428 – 03a.F428 – 09. DOI: 10.1520/F0428-09.10.1520/F0428-09R14.
The sole source of supply of the Glass Scratch Visual Comparison Standard known to the committee at this time is Davidson Optronics, Inc., 2223 Ramona Blvd., West
Covina, CA 91790. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful
consideration at a meeting of the responsible technical committee, which you may attend.
Originally an adjunct that contained seven scratches was used. The finest scratch (ASTM F428-2) was determined to be too difficult to use and manufacture. Subsequently,
it has been discontinued. Continued use of the older, seven-piece set is acceptable.
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