ASTM D5420-21

Standard Test Method for Impact Resistance of Flat, Rigid Plastic Specimen by Means of a Striker Impacted by a Falling Weight (Gardner Impact)

SIGNIFICANCE AND USE
5.1 Plastics are viscoelastic and it is possible that they are sensitive to changes in velocity of weights falling on their surfaces. However, the velocity of a free-falling object is a function of the square root of the drop height. A change of a factor of two in the drop height will cause a change of only 1.4 in velocity. Hagan, et al (2) found that the mean-failure energy of sheeting was constant at drop heights between 0.30 and 1.4 m. Different materials respond differently to changes in the velocity of impact.  
5.2 The test conditions used in Geometry GA are the same as those used in Geometry FA of Test Method D5628 (see Table 1).  
5.3 The test conditions of Geometry GB are equivalent to the geometry used for the Gardner Variable Height Impact Test (3).  
5.4 The test conditions of Geometry GC cause a punch-shear type of failure because the support-plate hole is close to the diameter of the striker.  
5.5 The test conditions of Geometry GD are the same as those in Test Method D3763.  
5.6 The test conditions of Geometry GE are the same as those in Test Method D4226, impactor head configuration H.25.  
5.7 Because of the nature of impact testing, the selection of a test method and striker must be somewhat arbitrary. Consider the end use environment and requirements when choosing from the available striker geometries. The selection of any one of the striker geometries is permitted.
Note 2: Material processing can have a significant affect on the development of a plastic's physical properties. Consult relevant material standards for processing guidelines
SCOPE
1.1 This test method covers the determination of the relative ranking of materials according to the energy required to crack or break flat, rigid plastic specimens under various specified conditions of impact of a striker impacted by a falling weight.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: There is no known ISO equivalent to this standard.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Jan-2021
• ICS: 83.140.10 - Films and sheets
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D5420 − 21
Standard Test Method for
Impact Resistance of Flat, Rigid Plastic Specimen by Means
1
of a Striker Impacted by a Falling Weight (Gardner Impact)
This standard is issued under the fixed designation D5420; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* D4226Test Methods for Impact Resistance of Rigid Poly-
(Vinyl Chloride) (PVC) Building Products
1.1 Thistestmethodcoversthedeterminationoftherelative
D5628Test Method for Impact Resistance of Flat, Rigid
ranking of materials according to the energy required to crack
Plastic Specimens by Means of a Falling Dart (Tup or
or break flat, rigid plastic specimens under various specified
Falling Mass)
conditions of impact of a striker impacted by a falling weight.
D5947Test Methods for Physical Dimensions of Solid
1.2 The values stated in SI units are to be regarded as the
Plastics Specimens
standard. The values given in parentheses are for information
E171Practice for Conditioning and Testing Flexible Barrier
only.
Packaging
1.3 This standard does not purport to address all of the E456Terminology Relating to Quality and Statistics
safety concerns, if any, associated with its use. It is the
E691Practice for Conducting an Interlaboratory Study to
responsibility of the user of this standard to establish appro- Determine the Precision of a Test Method
priate safety, health, and environmental practices and deter-
E2935Practice for Conducting Equivalence Tests for Com-
mine the applicability of regulatory limitations prior to use. paring Testing Processes
NOTE 1—There is no known ISO equivalent to this standard.
3. Terminology
1.4 This international standard was developed in accor-
3.1 Definitions—Definitions are in accordance with Termi-
dance with internationally recognized principles on standard-
nologies D883 and D1600, unless otherwise specified. For
ization established in the Decision on Principles for the
terms relating to precision and bias and associated issues, the
Development of International Standards, Guides and Recom-
terms used in this standard are defined in accordance with
mendations issued by the World Trade Organization Technical
Terminology E456.
Barriers to Trade (TBT) Committee.
3.2 Definitions of Terms Specific to This Standard:
2. Referenced Documents
3.2.1 failure (of test specimen)—the presence of any crack
2
2.1 ASTM Standards:
or split created by the impact of the falling weight that can be
D618Practice for Conditioning Plastics for Testing
seen by the naked eye under normal laboratory lighting
D883Terminology Relating to Plastics
conditions.
D1600TerminologyforAbbreviatedTermsRelatingtoPlas-
3.2.1.1 Discussion—Failure shall include the following:
tics
(1) complete shattering of the plaque; (2) any crack radiating
D2794Test Method for Resistance of Organic Coatings to
out toward the edges of the plaque on either surface of the
the Effects of Rapid Deformation (Impact)
plaque; (3) any radial crack within or just outside the impact
D3763Test Method for High Speed Puncture Properties of
area of the striker; (4) any hole in the plaque, whether due to
Plastics Using Load and Displacement Sensors
brittle or ductile puncture, where unobstructed light or water
D4066Classification System for Nylon Injection and Extru-
could pass through; (5) any brittle splitting of the bottom
sion Materials (PA)
surface of the plaque; and (6) any glassy-type chip dislodged
from or loosened from the plaque.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
3.2.1.2 Discussion—Refertotheappropriatematerialspeci-
and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
ficationforguidanceontheinterpretationoffailuredifferences
Current edition approved Jan. 15, 2021. Published February 2021. Originally
between material types.
approved in 1993. Last previous edition approved in 2016 as D5420-16. DOI:
10.1520/D5420-21.
3.2.1.3 Discussion—Cracks usually start at the surface op-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
posite the one that is struck. For example, in some cases
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
incipient cracking in glass-reinforced polymers is difficult to
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. differentiate from the reinforcing fibers. In such cases, apply a
*A Summary of Changes section appears at the end of
...

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: D5420 − 16 D5420 − 21
Standard Test Method for
Impact Resistance of Flat, Rigid Plastic Specimen by Means
1
of a Striker Impacted by a Falling Weight (Gardner Impact)
This standard is issued under the fixed designation D5420; 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 determination of the relative ranking of materials according to the energy required to crack or
break flat, rigid plastic specimens under various specified conditions of impact of a striker impacted by a falling weight.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
NOTE 1—There is no known ISO equivalent to this standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
D2794 Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)
D3763 Test Method for High Speed Puncture Properties of Plastics Using Load and Displacement Sensors
D4066 Classification System for Nylon Injection and Extrusion Materials (PA)
D4226 Test Methods for Impact Resistance of Rigid Poly(Vinyl Chloride) (PVC) Building Products
D5628 Test Method for Impact Resistance of Flat, Rigid Plastic Specimens by Means of a Falling Dart (Tup or Falling Mass)
D5947 Test Methods for Physical Dimensions of Solid Plastics Specimens
E171 Practice for Conditioning and Testing Flexible Barrier Packaging
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Conducting Equivalence Tests for Comparing Testing Processes
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
Current edition approved May 1, 2016Jan. 15, 2021. Published May 2016February 2021. Originally approved in 1993. Last previous edition approved in 20102016 as
D5420 - 10.D5420 - 16. DOI: 10.1520/D5420-16.10.1520/D5420-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D5420 − 21
3. Terminology
3.1 Definitions—For definitions of plastics terms used in this test method, see Definitions are in accordance with Terminologies
D883 and D1600, unless otherwise specified. For terms relating to precision and bias and associated issues, the terms used in this
standard are defined in accordance with Terminology E456.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 failure (of test specimen)—the presence of any crack or split created by the impact of the falling weight that can be seen by
the naked eye under normal laboratory lighting conditions.
3.2.1.1 Discussion—
Failure shall include the following: (1) complete shattering of the plaque; (2) any crack radiating out toward the edges of the
plaque on either surface of the plaque; (3) any radial crack within or just outside the impact area of the striker; (4) any hole in
the plaque, whether due to brittle or ductile puncture, where unobstructed light or water could pass through; (5) any brittle splitting
of the
...