ASTM F428-03a

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F428–03a
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 The lightest scratch is identified as ASTM F 428-3 and the
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heaviest as ASTM F 428-8.
1.1 This test method covers the visual inspection of
scratches on the glass surface of aerospace transparent enclo-
6. Procedure
sures.
6.1 Place the part in a suitable inspection position.This may
1.2 This standard may involve hazardous materials, opera-
be horizontal on a padded table, vertical against a neutral to
tions, and equipment. This standard does not purport to
dark background, or at an angle simulating the installed
address all of the safety concerns, if any, associated with its
position. The scratched surface shall be toward the observer.
use. It is the responsibility of the user of this standard to
The light level shall be a minimum of 80 lux. Either natural or
establish appropriate safety and health practices and deter-
artificial light may be used. If possible, move the light until the
mine the applicability of regulatory limitations prior to use.
scratch has the highest contrast against the background. Place
2. Referenced Documents the scratch in the visual comparison standard beside and
parallel to the scratch in question. Rotate the part or viewing
2.1 Other Standards:
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angle to get the best definition of the scratch. Disregarding the
Glass Scratch Visual Comparison Standard
length of the scratch on the part and on the standard, select and
3. Summary of Test Method
record the standard that most closely matches the appearance
of the scratch on the part. Measure and record the length of the
3.1 A visual comparison is made between a set of graded
scratch to the nearest 1 mm (or 0.05 in.).
scratch standards and the scratch on the glass aerospace
transparency to determine the relative intensity of the scratch.
7. Interpretation
4. Significance and Use
7.1 Customer specifications for aerospace glass surfaced
transparent enclosures may detail allowable frequency, loca-
4.1 Scratchesexistonallglasssurfaces.Oftentherearevery
tion, length, and standard number for scratches and they may
fine scratches from cleaning operations that are not visible
assign maximum scratch limits for critical and noncritical
when looking through the glass. Visible scratches may be
optical viewing areas.
distracting to the observer looking through the enclosure.
Therefore, a procedure to define scratches is useful. A visual
8. Report
standard is used because it is not practical to measure the
8.1 For each scratch within the scope of the glass scratch
dimensions of the fine scratches in the scope of this test
standard, report its standard number, length, frequency, and
method.
location.
5. Reference Materials
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9. Precision and Bias
5.1 Glass Scratch Visual Comparison Standardconsistsofa
9.1 Precision:
set of six hermetically sealed glass plates 38 mm (1.5 in.)
9.1.1 The repeatability of judging the intensity of a scratch
square with scratches of graded intensity on the inside surface.
within one scratch value, for the same observer, is 90 % or
better.
1 9.1.2 The reproducibility (between observers) of judging
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 the intensity of a scratch within two scratch values is 87 % or
Transparent Enclosures and Materials.
better.
Current edition approved Oct. 1, 2003. Published November 2003. Originally
published in 1977. Last previous edition approved in 2003 as F 428 – 03.
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The sole source of supply of the Glass Scratch Visual Comparison Standard
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known to the committee at this time is Davidson Optronics, Inc., 2223 Ramona Originally an adjunct that contained seven scratches.The finest scratch (ASTM
Blvd., West Covina, CA 91790. If you are aware of alternative suppliers, please F 428–2) was determined to be too difficult to use and manufacture. Subsequently,
provide this information toASTM International Headquarters. Your comments will it has been discontinued. Continued use of the older, seven-piece set is acceptable.
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receive careful consideration at a meeting of the responsible technical committee, Aresearch report is available fromASTM International Headquarters. Request
which you may attend. RR:F07-1008.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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