ASTM F428-03
(Test Method)Standard Test Method for Intensity of Scratches on Aerospace Glass Enclosures
Standard Test Method for Intensity of Scratches on Aerospace Glass Enclosures
SCOPE
1.1 This test method covers the visual inspection of scratches on the glass surface of aerospace transparent enclosures.
1.2 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.
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Designation: F 428 – 03
Standard Test Method for
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Intensity of Scratches on Aerospace Glass Enclosures
This standard is issued under the fixed designation F 428; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope square with scratches of graded intensity on the inside surface.
The lightest scratch is identified as ASTM F 428-3 and the
1.1 This test method covers the visual inspection of
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heaviest as ASTM F 428-8.
scratches on the glass surface of aerospace transparent enclo-
sures.
6. Procedure
1.2 This standard may involve hazardous materials, opera-
6.1 Place the part in a suitable inspection position. This may
tions, and equipment. This standard does not purport to
be horizontal on a padded table, vertical against a neutral to
address all of the safety concerns, if any, associated with its
dark background, or at an angle simulating the installed
use. It is the responsibility of the user of this standard to
position. The scratched surface shall be toward the observer.
establish appropriate safety and health practices and deter-
The light level shall be a minimum of 80 lux. Either natural or
mine the applicability of regulatory limitations prior to use.
artificial light may be used. If possible, move the light until the
2. Referenced Documents scratch has the highest contrast against the background. Place
the scratch in the visual comparison standard beside and
2.1 Other Standards:
2 parallel to the scratch in question. Rotate the part or viewing
Glass Scratch Visual Comparison Standard
angle to get the best definition of the scratch. Disregarding the
3. Summary of Test Method length of the scratch on the part and on the standard, select and
record the standard that most closely matches the appearance
3.1 A visual comparison is made between a set of graded
of the scratch on the part. Measure and record the length of the
scratch standards and the scratch on the glass aerospace
scratch to the nearest 1 mm (or 0.05 in.).
transparency to determine the relative intensity of the scratch.
7. Interpretation
4. Significance and Use
7.1 Customer specifications for aerospace glass surfaced
4.1 Scratches exist on all glass surfaces. Often there are very
transparent enclosures may detail allowable frequency, loca-
fine scratches from cleaning operations that are not visible
tion, length, and standard number for scratches and they may
when looking through the glass. Visible scratches may be
assign maximum scratch limits for critical and noncritical
distracting to the observer looking through the enclosure.
optical viewing areas.
Therefore, a procedure to define scratches is useful. A visual
standard is used because it is not practical to measure the
8. Report
dimensions of the fine scratches in the scope of this test
8.1 For each scratch within the scope of the glass scratch
method.
standard, report its standard number, length, frequency, and
5. Reference Materials location.
5.1 Glass Scratch Visual Comparison Standard consists of a
9. Precision and Bias
set of six hermetically sealed glass plates 38 mm (1.5 in.)
9.1 Precision:
9.1.1 The repeatability of judging the intensity of a scratch
1 within one scratch value, for the same observer, is 90 % or
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
better.
Transparent Enclosures and Materials.
9.1.2 The reproducibility (between observers) of judging
Current edition approved Apr. 10, 2003. Published May 2003. Originally
the intensity of a scratch within two scratch values is 87 % or
published in 1977. Last previous edition approved in 2001 as F 428 – 01.
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better.
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
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provide this information to ASTM International Headquarters. Your comments will Originally an adjunct that contained seven scratches. The finest scratch (ASTM
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receive careful consideration at a meeting of the responsible technical committee, F 428–2) was determined to be too difficult to use and manufacture. Subsequently,
which you may attend. it has been discontinued. Continued use of the older, seven-piece set is acceptable.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superceded and replaced by a ne
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