ASTM D4168-95(2002)
(Test Method)Standard Test Methods for Transmitted Shock Characteristics of Foam-in-Place Cushioning Materials
Standard Test Methods for Transmitted Shock Characteristics of Foam-in-Place Cushioning Materials
SIGNIFICANCE AND USE
Data obtained by these methods may be used to determine the transmitted shock cushioning characteristics of foam-in-place packaging materials. These data allow design of cushioning systems that can provide adequate and efficient use of foam for protection of goods during a distribution life-cycle.
These methods, in contrast to other methods that usually test only the cushioning foam, are designed to evaluate foam-in-place cushioning materials in a manner in which the foam-in-place packaging material is used. In particular, the method includes simultaneous use of a plastic film, the foam, and the box usually used in this method of packaging. See Fig. 1.
FIG. 1 Specimen Ready For Test
SCOPE
1.1 These test methods determine the shock-absorbing characteristics of foam-in-place packaging materials.
1.2 Test Method A uses a free-fall package drop test apparatus.
1.3 Test Method B uses a shock-test apparatus.
1.4 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.
General Information
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Standards Content (Sample)
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Designation:D4168–95 (Reapproved 2002)
Standard Test Methods for
Transmitted Shock Characteristics of Foam-in-Place
Cushioning Materials
This standard is issued under the fixed designation D 4168; 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 3. Terminology
1.1 These test methods determine the shock-absorbing char- 3.1 Definitions:
acteristics of foam-in-place packaging materials. 3.1.1 acceleration—the rate of change of velocity of a body
1.2 Test Method A uses a free-fall package drop test appa- with respect to time, measured in inches per second per second
ratus. (metres per second per second).
1.3 Test Method B uses a shock-test apparatus. 3.1.2 velocity—the rate of change of position of a body in a
1.4 This standard does not purport to address all of the specified direction with respect to time, measured in inches per
safety concerns, if any, associated with its use. It is the second (metres per second).
responsibility of the user of this standard to establish appro- 3.2 Definitions of Terms Specific to This Standard:
priate safety and health practices and determine the applica- 3.2.1 equivalent free-fall height—the calculated height of
bility of regulatory limitations prior to use. free fall in a vacuum required for a falling body to attain a
measured or given impact velocity.
2. Referenced Documents
3.2.2 foam-in-place cushioning material—a material that is
2.1 ASTM Standards: formed by dispensing chemical components which react and
D 996 Terminology of Packaging and Distribution Environ-
expand to produce a foam cushioning material in a container or
ments mold.
D 1596 Test Method for Dynamic Shock Cushioning Char-
3.2.3 free rise core density—the density of a foam sample
acteristics of Packaging Material takenfromtheinteriorofabunoffoam(withoutskin)thatwas
D 3332 Test Methods for Mechanical-Shock Fragility of
produced under unrestricted (free-rise) conditions in pounds
Products, Using Shock Machines
per cubic foot (kilograms per cubic metre).
D 4332 Practice for Conditioning Containers, Packages, or 3.2.4 static loading—the applied mass in pounds (kilo-
Packaging Components for Testing
grams) divided by the area, measured in square inches (square
D 5276 Test Method for DropTest of Loaded Containers by metres) to which the mass is applied in pounds per squares
Free Fall
inches (kilograms per square metre).
D 5487 Test Method for Simulated Drop of Loaded Con- 3.2.5 velocity change—the sum of the impact velocity and
tainers by Shock Machines
any rebound velocity.
E 122 Practice for Calculating Sample Size to Estimate, 3.3 Symbols:Symbols:
With Specified Precision, the Average for a Characteristic
3.3.1 g—symbolfortheaccelerationduetotheeffectsofthe
of a Lot or Process earth’s gravitational pull. While somewhat variable, it is
usually considered a constant of value 386 in./s/s (9.8 m/s/s).
4. Summary of Test Methods
These test methods are under the jurisdiction of ASTM Committee D10 on
4.1 The test methods consist of using the cushioning mate-
Packaging and are the direct responsibility of Subcommittee D10.13 on Interior
rial to be tested to support a weighted test block inside a
Packaging.
package. The complete package is subjected to drops or
Current edition approved Oct. 10, 2002. Published July 1995. Originally
published as D 4168 – 82. Last previous edition D 4168 – 88.
controlled shocks and the accelerations transmitted to the test
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
block are measured.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.2 Either Test Method A or B may be used. However, the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. two methods will not necessarily give the same result.
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D4168–95 (2002)
5. Significance and Use 6.4 Test Block:
6.4.1 The test block shall have a rigid square bottom face of
5.1 Data obtained by these methods may be used to deter-
not less than 8 in. (203 mm) on a side. Its height shall be a
mine the transmitted shock cushioning characteristics of foam-
minimum of half the bottom square dimension and a maximum
in-place packaging materials. These data allow design of
of the full bottom square dimension.
cushioning systems that can provide adequate and efficient use
6.4.2 The test block shall include provisions for firmly
of foam for protection of goods during a distribution life-cycle.
mounting ballast weight to adjust its total weight to a desired
5.2 These methods, in contrast to other methods that usually
value.
test only the cushioning foam, are designed to evaluate
6.4.3 An accelerometer mounting attachment shall be pro-
foam-in-place cushioning materials in a manner in which the
vidednearthecenterofgravityoftheblock.Theblockshallbe
foam-in-place packaging material is used. In particular, the
designed and constructed to be as rigid as possible and to
method includes simultaneous use of a plastic film, the foam,
minimize motion of the various components.
and the box usually used in this method of packaging. See Fig.
6.4.4 A recommended configuration is shown in Fig. 2.
1.
Also, it is suggested that the box weight be evenly distributed
about the center of the bottom face of the test block.
6. Apparatus
6.4.5 Ballast weights are added or removed to achieve the
6.1 Test Method A:
desired static loading on the cushioning material. The acceler-
6.1.1 The free-fall drop test apparatus shall conform to the
ometer shall be considered as a portion of the ballast weight.
requirements as described in Test Method D 5276.
6.5 Outer Container, shall be a regular, slotted container
6.2 Test Method B:
(RSC) corrugated box fabricated with 200 psi (1380 kPa) test
6.2.1 The shock test apparatus shall conform to the require-
“C” flute fiberboard.
ments as described in Test Method D 5487.
6.3 Instrumention and Shock Sensors—Accelerometers,
7. Sampling
signal conditioners, and data storage apparatus are required to
7.1 Because users form their own cushioning materials, it is
monitor acceleration versus time histories at various points on
very important that accurate records be prepared of all physical
the test apparatus and test specimen. The instrumentation
data pertaining to those materials for later identification. In
systems shall have the following minimum properties:
addition, the specific characteristics of the film used with the
6.3.1 Frequency response range from 2 Hz or less to at least
cushion shall be recorded. Care must be taken to ensure that
1000 Hz.
samples are of representative quality. It is recommended that
6.3.2 Accuracy of reading to be within 65 % of the actual
all samples be allowed to cure and stabilize after being poured
value.
for a minimum period of 24 h before they are tested.
6.3.3 Cross-axis sensitivity less than 5 % of full scale.
7.2 Specimens—If any of the requirements of Sections 7
and 8 are not met, the container and cushioning material shall
be discarded and the procedure repeated with new material.
Fig. 1 shows a typical specimen assembled and ready for test.
FIG. 1 Specimen Ready For Test FIG. 2 Test Block
D4168–95 (2002)
8. Preparation of Test Specimens 9.1.2 Following the recommendations of the shock machine
manufacturer, adjust the machine to produce a shock pulse of
8.1 Modified Free-Rise Bottom Cushion Fabrication (Op-
notgreaterthan3mstotaldurationandavelocitychangeequal
tion 1):
to that calculated in 9.1.1.
8.1.1 Dispense a layer of the foam-in-place cushioning
9.1.3 Rigidly mount an accelerometer or velocity-
material into the bottom of the box. Place the barrier film over
measuring instrumentation such as optical sensors on the
the foam; then position the test block such that the foam will
carriage to measure this velocity change.
rise to a depth equal to the thickness to be tested.Alternatively,
9.1.4 Secure the test specimen to the shock table carriage in
a dummy test block jig referenced to the top of the box may be
such a way to ensure a flat impact of the test specimen.
used to ensure the correct position of the test block. The sides
of the foam cushion shall be 3 in. (76 mm) thick and should
NOTE 1—Instrumentation to mesaure the velocity change of the shock
come up about half of the depth of test block. Care must be
table is required. This may be a device that integrates the area electroni-
cally under the shock pulse wave form. Alternatively, it can be measured
taken to dispense a proper amount of foam in order that the
by photodiode-type devices that measure shock table impact and rebound
cushion samples are of representative quality, are not overly
velocity. Calculation that assumes the shock pulse to be a perfect
densified, and are free of large voids. See Fig. 3.
geometric figure is usually grossly inaccurate and should not be used. See
8.2 Premolded Bottom Cushion Fa
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