ASTM F320-16

Standard Test Method for Hail Impact Resistance of Aerospace Transparent Enclosures

SIGNIFICANCE AND USE
4.1 This test method shall be used to determine the hail impact resistance of windshields for acceptance, design, service, or research purposes. By coupling this method with the installed angle and velocity of a specific aerospace vehicle, design allowables, criteria, and tolerances can be established for that vehicle's windshield.
SCOPE
1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure, hereinafter called windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled conditions.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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. For specific hazard statements see Section 7.

General Information

• Status: Historical
• Publication Date: 31-Mar-2016
• ICS: 49.045 - Structure and structure elements
• Technical Committee: F07 - Aerospace and Aircraft
• Drafting Committee: F07.08 - Transparent Enclosures and Materials

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F320 −16
Standard Test Method for
Hail Impact Resistance of Aerospace Transparent
1
Enclosures
ThisstandardisissuedunderthefixeddesignationF320;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3. Summary of Test Method
1.1 This test method covers the determination of the impact 3.1 The test method involves launching a series of ice balls
resistance of an aerospace transparent enclosure, hereinafter of specified sizes at a sample windshield at a designated
velocity and angle and in a specified pattern. Requirements are
called windshield, during hailstorm conditions using simulated
hailstones consisting of ice balls molded under tightly con- specified for the ice ball, test specimen, procedure, and data
acquisition. The ice ball is photographed in flight to verify its
trolled conditions.
integrity.
1.2 The values stated in inch-pound units are to be regarded
3.2 Requirements are specified for a particular apparatus
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and test procedure, but options are permitted for certain areas.
However, it must be possible to demonstrate that the options
and are not considered standard.
usedresultinaniceballimpactingthetestpanelwiththesame
1.3 This standard does not purport to address all of the
size, consistency, and velocity as with the specified apparatus
safety concerns, if any, associated with its use. It is the
and procedure. Following are areas where options are allowed:
responsibility of the user of this standard to establish appro-
3.2.1 Ice Ball Mold Material.
priate safety and health practices and determine the applica-
3.2.2 Launcher—Any type of launcher is allowable as long
bility of regulatory limitations prior to use. For specific hazard
as the iceball reaches the test specimen intact at the correct
statements see Section 7.
speed. The use of sabots and sabot material and geometry are
optional.
2. Terminology
3.2.3 Method of Determining Ice Ball Integrity.
2.1 Definitions:
3.2.4 Ice Ball Speed Measurement, optional as long as
2.1.1 damage, n—any modification in visual properties or
accuracy standards are met.
integrity of a windshield as a result of hail impact including
3.2.5 Test Specimen Sizes—Those given are minimum.
scratches, crazing, delamination, cracks, or shattering.
3.2.6 Safety—Safety must satisfy the safety standards of the
2.1.2 ice ball, n—a frozen mass of water, with filler, that
test facility being used.
simulates a natural hailstone in weight, size, and toughness.
4. Significance and Use
2.1.3 impact angle, n—the angle between the ice ball flight
path and the target normal.
4.1 This test method shall be used to determine the hail
impact resistance of windshields for acceptance, design,
2.1.4 sabot, n—a plastic device for protecting the ice ball
service,orresearchpurposes.Bycouplingthismethodwiththe
whileinthelaunchtube.Onetypeofsabot(seeFig.1)consists
installed angle and velocity of a specific aerospace vehicle,
of a split polycarbonate rod containing a central cavity for
design allowables, criteria, and tolerances can be established
holding the ice ball. Each sabot half is designed to assure
for that vehicle’s windshield.
aerodynamic separation from the ice ball after ejection from
the launch tube.
5. Apparatus
5.1 The facilities and equipment required for the perfor-
1
mance of this test procedure include a suitable firing range
This test method is under the jurisdiction of ASTM Committee F07 on
Aerospace andAircraft and is the direct responsibility of Subcommittee F07.08 on
equipped with an ice ball mold, a launcher, blast deflector,
Transparent Enclosures and Materials.
sabot trap, velocity measuring system, test specimen holder,
Current edition approved April 1, 2016. Published April 2016. Originally
and a camera with strobe lights to verify ice ball integrity.
approved in 1978. Last previous edition approved in 2010 as F320–10. DOI:
10.1520/F0320-16. Ancillary equipment required for this test include test
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F320−16
5.2 Firing Range—The firing range shall be a minimum of
9 by 18 ft (3 by 6 m) enclosed to contain flying debris and to
exclude unauthorized personnel.
5.3 Ice Ball Mold,twoaluminumblockswithhemispherical
cavities and vent holes for filling with water and for water
expansion during freezing.
5.4 Launc
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F320 − 10 F320 − 16
Standard Test Method for
Hail Impact Resistance of Aerospace Transparent
1
Enclosures
This standard is issued under the fixed designation F320; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure, hereinafter called
windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled
conditions.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 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. For specific hazard statements see Section 7.
2. Terminology
2.1 Definitions:
2.1.1 damage—damage, n—any modification in visual properties or integrity of a windshield as a result of hail impact including
scratches, crazing, delamination, cracks, or shattering.
2.1.2 ice ball—ball, n—a frozen mass of water, with filler, that simulates a natural hailstone in weight, size, and toughness.
2.1.3 impact angle—angle, n—the angle between the ice ball flight path and the target normal.
2.1.4 sabot—sabot, n—a plastic device for protecting the ice ball while in the launch tube. One type of sabot (see Fig. 1) consists
of a split polycarbonate rod containing a central cavity for holding the ice ball. Each sabot half is designed to assure aerodynamic
separation from the ice ball after ejection from the launch tube.
3. Summary of Test Method
3.1 The test method involves launching a series of ice balls of specified sizes at a sample windshield at a designated velocity
and angle and in a specified pattern. Requirements are specified for the ice ball, test specimen, procedure, and data acquisition.
The ice ball is photographed in flight to verify its integrity.
3.2 Requirements are specified for a particular apparatus and test procedure, but options are permitted for certain areas.
However, it must be possible to demonstrate that the options used result in an ice ball impacting the test panel with the same size,
consistency, and velocity as with the specified apparatus and procedure. Following are areas where options are allowed:
3.2.1 Ice Ball Mold Material.
3.2.2 Launcher—Any type of launcher is allowable as long as the iceball reaches the test specimen intact at the correct speed.
The use of sabots and sabot material and geometry are optional.
3.2.3 Method of Determining Ice Ball Integrity.
3.2.4 Ice Ball Speed Measurement, Optionaloptional as long as accuracy standards are met.
3.2.5 Test Specimen Sizes—Those given are minimum.
3.2.6 Safety—Safety must satisfy the safety standards of the test facility being used.
1
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 1, 2010April 1, 2016. Published June 2010April 2016. Originally approved in 1978. Last previous edition approved in 20052010 as
F320 – 05.F320 – 10. DOI: 10.1520/F0320-10.10.1520/F0320-16.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F320 − 16
FIG. 1 Sabot Configuration
4. Significance and Use
4.1 This test method mayshall be used to determine the hail impact resistance of windshields for acceptance, design, service,
or research purposes. By coupling this method with the installed angle and velocity of a specific aerospace vehicle, design
allowables, criteria, and tolerances can be established for that vehicle’s windshield.
5. Apparatus
5.1 The facilities and equipment required for the performance of this test procedure include a suitable firing range equipped with
an ice ball mold, a launcher, blast deflector, sabot trap, velocity
...