ASTM D3574-17

Standard Test Methods for Flexible Cellular Materials—Slab, Bonded, and Molded Urethane Foams

SIGNIFICANCE AND USE
5.1 The test procedures provide a standard method of obtaining data for research and development, quality control, acceptance and rejection under specifications, and special purposes.  
5.2 The data obtained by these test methods are applicable to the material under conditions of the particular test and are not necessarily the same as obtained in other environments in use.
SCOPE
1.1 These test methods apply to slab, bonded, and molded flexible cellular products known as urethane foams. Urethane foam is generally defined as an expanded cellular product produced by the interaction of active hydrogen compounds, water, and isocyanates.  
1.2 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.  
1.3 The values stated in SI units are to be regarded as standard.
Note 1: There is no known ISO equivalent to this standard, however certain test methods in this standard have similar or equivalent ISO standards and are listed in the scope of the individual test method sections.

General Information

• Status: Published
• Publication Date: 28-Feb-2017
• ICS: 83.100 - Cellular materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D3574-16 - Standard Test Methods for Flexible Cellular Materials—Slab, Bonded, and Molded Urethane Foams
• Effective Date: 01-Mar-2017
• Refers: ASTM E662-18 - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Dec-2018
• Refers: ASTM E662-17a - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Jul-2017
• Refers: ASTM D3675-17 - Standard Test Method for Surface Flammability of Flexible Cellular Materials Using a Radiant Heat Energy Source
• Effective Date: 01-May-2017
• Refers: ASTM E662-17 - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Feb-2017
• Refers: ASTM D737-04(2016) - Standard Test Method for Air Permeability of Textile Fabrics
• Effective Date: 01-Jul-2016
• Refers: ASTM D3675-16 - Standard Test Method for Surface Flammability of Flexible Cellular Materials Using a Radiant Heat Energy Source
• Effective Date: 01-May-2016
• Refers: ASTM E162-15b - Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
• Effective Date: 15-Dec-2015
• Refers: ASTM E662-15a - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Nov-2015
• Refers: ASTM E162-15a - Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
• Effective Date: 01-Jul-2015
• Refers: ASTM E162-15 - Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
• Effective Date: 01-Jun-2015
• Refers: ASTM E662-15 - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Apr-2015
• Refers: ASTM E662-14 - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Aug-2014
• Refers: ASTM D3675-14 - Standard Test Method for Surface Flammability of Flexible Cellular Materials Using a Radiant Heat Energy Source
• Effective Date: 01-Mar-2014
• Refers: ASTM E662-13d - Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
• Effective Date: 01-Aug-2013

Overview

ASTM D3574-17, titled "Standard Test Methods for Flexible Cellular Materials-Slab, Bonded, and Molded Urethane Foams," establishes comprehensive procedures for the testing and evaluation of urethane foam products. Developed by ASTM International, this standard is applicable to slabstock, bonded, and molded flexible polyurethane foams. The document provides standard methods for obtaining data that support applications in research and development, quality control, and acceptance testing.

The test methods are essential for manufacturers, suppliers, and product developers to ensure consistent quality and performance of urethane foam products. Data derived from these tests are specific to the tested materials and conditions and may not directly represent in-service environments. ASTM D3574-17 is recognized by various regulatory bodies and referenced for compliance and product safety.

Key Topics

• Types of Urethane Foams Covered: Slab, bonded, and molded flexible polyurethane foams produced by reacting active hydrogen compounds, water, and isocyanates.
• Comprehensive Test Methods: Includes procedures for assessing:
  • Density
  • Indentation Force Deflection (IFD)
  • Indentation Residual Gauge Length (IRGL)
  • Compression Force Deflection
  • Constant Deflection Compression Set
  • Tensile Strength and Elongation
  • Tear Resistance
  • Air Flow Permeability
  • Resilience, Fatigue, Aging, and Recovery
• Testing Environment: All tests are conducted under standard laboratory conditions (23 ± 2°C, 50 ± 10% relative humidity), with products conditioned and undistorted at least 12 hours before testing.
• Terminology and Definitions: Provides precise definitions for terms like bonded foam, cored foam, convoluted foam, skin, viscoelastic foam, cell count, and support factor.

Applications

ASTM D3574-17 enables a wide range of stakeholders to validate material properties and product suitability, including:

• Product Development: R&D teams use standardized test data to refine foam formulations and enhance characteristics such as support, comfort, and durability.
• Quality Control: Manufacturers rely on these test methods for routine inspection to ensure consistency across product batches.
• Specification Compliance: Provides reliable criteria for customer acceptance, rejection, and competitive benchmarking.
• Performance Evaluation: Helps evaluate foam resilience, fatigue resistance, structural integrity, and in-use comfort for products such as mattresses, automotive seating, furniture, packaging, and cushioning materials.
• Safety and Regulatory Adherence: Offers a reference for complying with safety and performance regulations in international and domestic markets.

Related Standards

While ASTM D3574-17 is a unique standard, it references and aligns with several other international and ASTM standards for specific tests and terminology, including:

• ASTM D412 – Test Methods for Vulcanized Rubber and Thermoplastic Elastomers-Tension
• ASTM D624 – Test Method for Tear Strength of Conventional Vulcanized Rubber and Thermoplastic Elastomers
• ASTM D737 – Test Method for Air Permeability of Textile Fabrics
• ASTM D3576 – Test Method for Cell Size of Rigid Cellular Plastics
• ASTM D3675 – Test Method for Surface Flammability of Flexible Cellular Materials
• ISO Standards – While there is no direct ISO equivalent, similar testing concepts exist in ISO 845 (density), ISO 2439 (indentation), ISO 3386 (compression), ISO 1856 (compression set), ISO 1798 (tensile), ISO 8067 (tear), and ISO 7231 (air flow).
• ASTM E162 / E662 – Test Methods for Surface Flammability and Optical Density of Smoke

Practical Value

Complying with ASTM D3574-17 ensures that flexible urethane foam materials consistently meet industry standards for mechanical and physical properties. The standardized methods foster clearer communication between suppliers and buyers, minimize disputes, and facilitate the development of superior, safer, and more reliable foam products across various application sectors.

For technical professionals engaged in foam materials, adhering to these test methods is fundamental for market access, customer satisfaction, and ongoing innovation in flexible foam solutions.

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: D3574 − 17
Standard Test Methods for
Flexible Cellular Materials—Slab, Bonded, and Molded
Urethane Foams
This standard is issued under the fixed designation D3574; 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* E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 These test methods apply to slab, bonded, and molded
flexible cellular products known as urethane foams. Urethane
3. Terminology
foam is generally defined as an expanded cellular product
3.1 Definitions of Terms Specific to This Standard:
produced by the interaction of active hydrogen compounds,
3.1.1 bonded foam—a product produced by the adhesion of
water, and isocyanates.
small pieces of urethane foam to each other with a suitable
1.2 This standard does not purport to address all of the
bonding agent.
safety concerns, if any, associated with its use. It is the
3.1.2 core—the internal portion of a molded part, free of
responsibility of the user of this standard to establish appro-
skin.
priate safety and health practices and determine the applica-
3.1.3 cored foam—a flexible cellular material containing a
bility of regulatory limitations prior to use.
multiplicity of holes (usually, but not necessarily, cylindrical in
1.3 The values stated in SI units are to be regarded as
shape), molded or cut into the material in some pattern,
standard.
NOTE 1—There is no known ISO equivalent to this standard, however normally perpendicular to the foam rise direction, and extend-
certain test methods in this standard have similar or equivalent ISO
ing part or all the way through the piece.
standardsandarelistedinthescopeoftheindividualtestmethodsections.
3.1.4 convoluted foam—a flexible cellular material specially
cut into sheets with “egg carton”-like dimples. The dimple
2. Referenced Documents
peaks and bases can have varied shapes and dimensions.
2.1 ASTM Standards:
3.1.5 flexible cellular product—a cellular organic polymeric
D412 Test Methods forVulcanized Rubber andThermoplas-
materialthatwillnotrupturewhenaspecimen200by25by25
tic Elastomers—Tension
mmisbentarounda25-mmdiametermandrelatauniformrate
D624 Test Method for Tear Strength of Conventional Vul-
ofonelapin5sata temperature between 18 and 29°C.
canized Rubber and Thermoplastic Elastomers
3.1.6 molded foam—a cellular product having the shape of
D737 Test Method for Air Permeability of Textile Fabrics
the enclosed chamber in which it is produced by foaming.
D3576 Test Method for Cell Size of Rigid Cellular Plastics
D3675 Test Method for Surface Flammability of Flexible
3.1.7 skin—the smooth surface layer of a molded foam
Cellular Materials Using a Radiant Heat Energy Source
product, formed by contact with the mold or surfaces.
E162 Test Method for Surface Flammability of Materials
3.1.8 slab—a section of foam that is cut from the internal
Using a Radiant Heat Energy Source
portion of a large bun.
E662 Test Method for Specific Optical Density of Smoke
3.1.9 urethane foam—a flexible cellular product produced
Generated by Solid Materials
by the interaction of active hydrogen compounds, water, and
isocyanates.
1 3.1.10 viscoelastic foam—a specially formulated urethane
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular foam characterized by having slow recovery, low resilience,
Materials - Plastics and Elastomers.
and high hysteresis loss.
Current edition approved March 1, 2017. Published March 2017. Originally
3.1.11 cell count—a measurement used to characterize dif-
approved in 1977. Last previous edition approved in 2016 as D3574 – 16. DOI:
10.1520/D3574-17.
ferent types of foams based on the size of the individual cells
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
in the foam matrix, typically expressed as either average cell
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
diameter or as the number of cells per linear distance. For
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. measuring cell counts, see Test Method D3576.
*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
D3574 − 17
3.1.12 clickability—the ability of a flexible cellular material 6.3 For mechanical tests, it is advisable to carefully select
to recover from the pinching effects of die cutting. the proper load cell for each test. It is recommended that the
expected load for any individual test falls within 10-90 % of
4. Summary of Test Methods the load cell capacity.
4.1 Unless otherwise specifically stated and agreed upon by
7. Sampling
the purchaser and the supplier, all tests shall be made in
accordance with the methods specified in Sections 9 – 150,
7.1 When possible, the completed manufactured product
which include test procedures for the following:
shall be used for the test specified. Representative samples of
Tests: Sections thelotbeingexaminedshallbeselectedatrandom,asrequired.
Test A Density Test 9–15
Test B Indentation Force Deflection Test—Specified 16–22
1 7.2 When it is necessary or advisable to obtain specimens
Deflection (IFD)
from the articles, as in those cases where the entire sample is
Test B Indentation Residual Gauge Length Test— 23–29
not required or adaptable for testing, the method of cutting and
Specified
Force (IRGL)
the exact position from which specimens are to be taken shall
Test C Compression Force Deflection Test 30–36
be specified. The density and the state of cure can vary in
Test D Constant Deflection Compression Set Test 37–44
differentpartsofthefinishedproduct,especiallyifthearticleis
Test E Tensile Test 45–52
Test F Tear Resistance Test 53–60
of complicated shape or of varying thickness, and these factors
Test G Air Flow Test 61–67
affect the physical properties of the specimens. Also, the
Test H Resilience (Ball Rebound) Test 68–75
density is affected by the number of cut surfaces on the
Test I Static Force Loss Test at Constant Deflection 77–85
Test I Dynamic Fatigue Test by Roller Shear at Con- 86–94
specimen. If a test specimen is die cut, ensure that the sides are
stant Force
not concave and allow sufficient time for complete recovery of
Test I Dynamic Fatigue Test by Constant Force 95 – 103
Pounding the thickness across the full width of the specimen before
Test I Dynamic Fatigue Test for Carpet Cushion 104 – 112
testing.
Test I Dynamic Fatigue Test by Constant Deflection 113 – 121
Pounding
7.3 Whenthefinishedmoldedproductdoesnotlenditselfto
Aging Test J Steam Autoclave Aging 122 – 127
testing or to the taking of specimens because of complicated
Aging Test K Dry Heat Aging 128 – 133
Aging Test L Wet Heat Aging 134 – 139
shape, small size, metal or fabric inserts, adhesion to metal, or
Test M Recovery Time 140 – 145
other reasons, molded test slabs, as agreed upon between the
Test N Hysteresis Loss 146 – 150
purchaser and the supplier, shall be prepared.
Appendixes:
7.4 Whendifferencesintestresultsariseduetothedifficulty
X1. Suggested Method for Specifying Flexible Urethane Foams
X2. Suggested Method of Construction for a Roller Shear Dynamic Flex
in obtaining suitable specimens from the finished parts, the
Fatigue Apparatus
purchaser and the supplier shall agree upon an acceptable
X3. Definitions of Terms Used to Describe the Force-Deflection Curve of
location from which to take the specimen.
Flexible Urethane Foam
X4. Suggested Tests for Determining Combustibility of Flexible Urethane
Foam. (The combustion tests are given for informational purposes only
8. Measurement of Test Specimens
and are not part of the standard.)
X5. Suggested Method for the Verification of an Inclined Oil Manometer
8.1 Measure the length and width with a scale, tape, or
caliper gauge. Take care not to distort the foam.
5. Significance and Use
8.2 Measure thickness up to and including 25 mm using a
5.1 The test procedures provide a standard method of
height or electronic display gauge with a minimum foot area of
obtaining data for research and development, quality control,
650 mm . Hold the pressure of the gauge foot to a maximum
acceptance and rejection under specifications, and special
of 800 Pa (see Note 2). Thicknesses over 25 mm shall be
purposes.
measured with a height or electronic display gauge, a sliding
5.2 The data obtained by these test methods are applicable
caliper gauge, or as specified in 8.1. When a sliding caliper
to the material under conditions of the particular test and are
gauge is employed, make the gauge setting with the gauge out
not necessarily the same as obtained in other environments in
of contact with the foam. Pass the specimen through the
use.
previously set gauge; the proper setting shall be the one when
the measuring faces of the gauge contact the surfaces of the
6. General Test Conditions
specimen without compressing it.
6.1 Tests shall be entirely conducted at 23 6 2 °C and 50 6
NOTE 2—For soft foams having compression force deflection values
10 % relative humidity, unless otherwise specified in the
less than 1.65 kPa, the pressure on the gauge or compression foot shall not
individual test method. The product shall be conditioned,
exceed 200 Pa.
undeflected and undistorted, at 23 6 2 °C and 50 6 10 %
8.3 The scale, tape, or gauge shall be graduated so as to
relative humidity, for at least 12 h before being tested, unless
permit measurements within 61 % of the dimensions to be
otherwise specified in the individual test method.
measured.
6.2 It is recommended for referee purposes that all tests be
performed seven days or more after the foam has been 8.4 Unless otherwise specified, results shall be the mean of
manufactured. the measurements.
D3574 − 17
TEST A—DENSITY TEST measuring the force necessary to produce designated indenta-
tions in the foam product, for example, indentations at 25 and
9. Scope
65 % deflections. (See Appendix X3 for additional informa-
9.1 This test method covers determination of the density of
tion).
uncored foam by calculation from the mass and volume of the
NOTE 4—This standard and ISO 2439 address the same subject matter,
specimen. The density value thus obtained applies only to the
but differ in technical content and results cannot be directly compared
immediate area from which the specimen has been taken. It
between the two methods.
does not necessarily relate to the bulk density of the entire
17. Apparatus
molded pad.
NOTE 3—This standard is equivalent to ISO 845. 17.1 An apparatus having a flat circular indenter foot 200
+3/–0 mm in diameter connected by means of a swivel joint
10. Test Specimen
capable of accommodating the angle of the sample to a
10.1 Core Density—A representative specimen of regular
force-measuring device and mounted in such a manner that the
shape, circular or square without skins or densification lines,
product or specimen can be deflected at a speed of 50 to 250
3 3
not less than 10,000 mm (~0.61 in. ) in volume, shall be cut
mm/min. The apparatus shall be arranged to support the
from a portion free of voids and defects and as near as possible
specimen on a level horizontal plate which is perforated with
to the section from which the tension and tear specimens were
approximately 6.5-mm holes on approximately 20-mm centers
taken.
to allow for rapid escape of air during the test. Special supports
10.2 Section Density—Arepresentative specimen with skins for contoured molded pads shall be perforated in the same
manner as the flat plate, unless otherwise agreed upon between
on the top and bottom surface measuring at least 0.1 m in area
by full-part thickness, shall be cut from an area free of voids the purchaser and the supplier. Pads longer than the base plate
shall be supported from distortion at the 4.5-N contact force
and defects and as near as possible to the location from which
the tension and tear specimens were taken. When these (see 20.3).
dimensions are not possible, the largest representative portion
NOTE 5—Equipment design and test fixturing can affect the results of
asagreeduponbetweenthepurchaserandthesupplier,shallbe
this test. As an example, load cells placed below the support plate can
used. experience a bridging effect that likely does not occur in equipment which
has the load cell mounted above the indenter foot.
11. Number of Specimens
18. Test Specimen
11.1 One specimen shall be tested, unless otherwise agreed
upon by the purchaser and the supplier.
18.1 The test specimen shall consist of the entire product
sample or a suitable portion of it, except that in no case shall
12. Procedure
the specimen have dimensions less than 380 by 380 by 100
12.1 Determine the mass of the specimen to a precision of
mm. If specimens are less than (or different from) 100 mm in
61%.
thickness, the thickness shall be noted on the test report.
12.2 Determine the dimensions of the specimen in accor-
18.2 The IFD values for molded products are dependent on
dance with Section 8, and calculate the volume.
the specimen dimensions. Higher values are generally obtained
for specimens that retain all molded surfaces.
13. Calculation
13.1 Calculate the density in kilograms per cubic metre as
19. Number of Specimens
follows:
19.1 One specimen shall be tested, unless otherwise agreed
Density 5 M/V 310 (1)
upon by the purchaser and the supplier.
where:
20. Procedure
M = mass of specimen, g, and
20.1 Place the test specimen in position on the supporting
V = volume of specimen, mm .
plate of the apparatus. If the product has one side cored or
14. Report
convoluted, this face shall rest on the perforated plate. The
specimen position shall be such that, whenever practicable, the
14.1 Report the following information:
indentation will be made at the center of the specimen, except
14.1.1 Density to the nearest 0.1 kg/m , and
when another location is agreed upon by the purchaser and the
14.1.2 Type of specimen, core or section.
supplier.
15. Precision and Bias
20.2 Preflex the test area twice to a deflection of 75 to 80 %
15.1 See Section 151 for Precision and Bias statements.
ofthefull-partthickness,loweringandraisingtheindenterfoot
at a rate of 250 6 25 mm/min, allowing the indenter to fully
TEST B —INDENTATION FORCE DEFLECTION
clear the top of the specimen after each preflex. For fatigue
TEST—SPECIFIED DEFLECTION (IFD)
tests, or in case repeat testing proves necessary, mark the
16. Scope
location of the test area by circumscribing the indenter foot
16.1 This will be known as the indentation force deflection with a pen.Allow the specimen to rest for 6 6 1 min after the
test and the results as the IFD values. This test consists of final preflex.
D3574 − 17
20.3 Bring the indenter foot into contact with the specimen 24.2 Special supports for contoured molded pads shall be
at a rate of 50 6 5 mm/min and determine the thickness while perforated and agreed upon between the purchaser and the
applying a contact force of 4.5 6 0.5 N to the indenter foot. supplier. Pads longer than the base plate shall be supported
For super-soft foam, with a 25 % IFD less than 40 N, a from distortion at the 4.5-N contact force (see 27.2).
reduction of pressure on the indenter foot shall be allowed.
25. Test Specimen
Sufficient contact force to make an accurate initial thickness
measurement is required. Indent the specimen at a rate of 50 6
25.1 When possible, the finished manufactured product
5 mm/min 25 % of this thickness and observe the force in
shall be used. In the case of tapered cushions, the location of
newtons after 60 6 3 s. Without removing the specimen,
the area for measurement is to be agreed upon between the
increase the deflection to 65 % deflection, allowing the force to
purchaserandthesupplier.Incaseafinishedpartisnotfeasible
drift while maintaining the 65 % deflection, and again observe
for test, 380 by 380-mm specimens of an average thickness are
the force in newtons after 60 63s.
to be cut from the cushion.
25.2 The IRGL values for molded products are dependent
21. Report
on the specimen dimensions. Different values are generally
21.1 Report the force in newtons required for 25 % and
obtained for specimens that retain all molded surfaces.
65 % indentation or other indentations (see Note 6). These
figures are known as the 25 % and 65 % IFD values, respec-
26. Number of Specimens
tively. Report length, width, and thickness of the specimen, if
26.1 One specimen shall be tested, unless otherwise agreed
non-standard,andtheratioof65 %to25 %IFDvalues(thatis,
upon by the purchaser and the supplier.
support factor, see Appendix X3).
27. Procedure
NOTE6—Indentationdeflectiontests,otherthan25 %and65 %,aswell
as a 25 % return value (25 % RT), may be specified as agreed upon
27.1 Testthewholetestspecimenoraminimumareaof380
between the purchaser and the supplier. Alternative or additional deflec-
by 380 mm. Position the specimen in the test apparatus with
tions shall be performed as described in 20.3.
any cored or convoluted surfaces resting against the perforated
22. Precision and Bias
bottom plate. Preflex the specimen twice with a 330 N force,
raising and lowering the indenter foot at 200 6 20 mm/min,
22.1 See Section 151 for Precision and Bias statements.
allowing the indenter foot to fully clear the top of the specimen
TEST B —INDENTATION RESIDUAL GAUGE
2 after each preflex. Allow the specimen to rest for 6 6 1 min
LENGTH TEST—SPECIFIED FORCE (IRGL)
after the final preflex.
27.2 At a rate of 50 6 5 mm/min, bring the indenter foot
23. Scope
into contact with and determine the thickness of the specimen,
23.1 Cellularfoamproductshavetraditionallybeenchecked
in mm, with a 4.5 6 0.5-N load on the indenter foot.
for indentation force deflection by determining the force
27.3 Apply the 110-N force at 50 6 5 mm/min with the
required to effect a 25 % deflection. In seating, on the other
indenter foot until the force is carried by the specimen.
hand, the interest is in determining how thick the padding is
Determine the thickness, in mm, at 110 N after maintaining the
undertheaverageperson.Threemeasurementsarecalledforto
force for 60 63s.
meet the requirements of this test method. The force deflection
is determined by measuring the thickness of the pad under a
27.4 Withoutremovingthespecimen,applythe220-Nforce
fixed force of 4.5 N, 110 N, and 220 N, with a 200 + 3/– 0 mm
at 50 6 5 mm/min with the indenter foot until the force is
circular indenter foot.
carried by the specimen. Determine the thickness, in mm, at
220 N after maintaining the force for 60 63s.
23.2 This determination shall be known as the Indentation
Residual Gauge Length and the measurements as the IRGL
28. Report
values.
28.1 Report the specimen thickness, in mm, at 4.5 N
NOTE 7—This standard and ISO 2439 address the same subject matter,
instantaneously and at 110 N and 220 N after 60 6 3 s. These
but differ in technical content; and results cannot be directly compared
figures are known as the IRGLvalues, respectively. Report the
between the two methods.
length, width, and thickness of the specimen.
24. Apparatus
29. Precision and Bias
24.1 An apparatus having a flat circular indenter foot 200
+3/–0 mm in diameter, connected with a swivel joint for
29.1 See Section 151 for Precision and Bias statements.
applying forces of 4.5 N, 110 N, 220 N and 330 N, shall be
TEST C—COMPRESSION FORCE
mountedoveralevelhorizontalplatformthatisperforatedwith
DEFLECTION TEST
approximately 6.5-mm holes on approximately 20-mm centers
to allow for rapid escape of air during the test. The distance
30. Scope
between the indenter foot and the platform shall be variable to
indent the specimen at a speed of 50 to 250 mm/min for 30.1 This test consists of measuring the force necessary to
thickness measurements. The apparatus shall be equipped with produce a 50 % compression over the entire top area of the
a device for measuring the distance between plates. foam specimen.
D3574 − 17
NOTE 8—This standard and ISO 3386 address the same subject matter,
35. Report
but differ in technical content; and results cannot be directly compared
35.1 Report the thickness after contact force, the 50 %
between the two methods.
compression deflection value in kilopascals, and the dimen-
NOTE 9—Compression force deflection tests other than at 50 % may be
specified, as agreed upon between the purchaser and the supplier, sions of non-standard specimens. Indicate if the sample was
following the procedure in Section 34.
cored or convoluted. Report if the specimens contained one or
more molded surfaces.
31. Apparatus
36. Precision and Bias
31.1 An apparatus having a flat, fixed compression foot,
larger than the specimen to be tested, connected to a force- 36.1 See Section 151 for Precision and Bias statements.
measuring device and mounted in a manner such that the
TEST D—CONSTANT DEFLECTION COMPRESSION
product or specimen can be deflected at a speed of 50 to 500
SET TEST
mm/min. The apparatus shall be arranged to support the
specimen on a level horizontal plate that is perforated with
37. Scope
approximately 6.5-mm holes on approximately 20-mm centers
to allow for rapid escape of air during the test. 37.1 This test method consists of deflecting the foam
specimen to a specified deflection, exposing it to specified
conditions of time and temperature and measuring the change
32. Test Specimens
in the thickness of the specimen after a specified recovery
32.1 The test specimens shall have parallel top and bottom
period.
surfaces and vertical sides. The thickness shall be no greater
NOTE 10—This standard and ISO 1856 address the same subject matter,
than 75 % of the minimum top dimension. The standard
but differ in technical content and results cannot be directly compared
specimen shall be 50 mm by 50 mm by 25 mm in thickness. between the two methods.
Larger specimens are preferable, where possible.
38. Apparatus
32.2 Specimensshallbeaminimumof2500mm insurface
38.1 Compression Device, consisting of two or more flat
area and have a minimum thickness of 20 mm.
plates arranged so the plates are held parallel to each other by
32.3 Unless otherwise agreed upon by purchaser and
bolts or clamps and the space between the plates is adjustable
supplier, specimens from molded parts shall be cut from the
to the required deflection thickness by means of spacers. The
corematerialatleast10mmbelowthemoldedsurface.Notein
plates shall be metal in composition and have sufficient
the report if the specimens contain one or more molded
stiffness to ensure that they are not deflected under the force
surfaces resulting from insufficient core material or contractual
necessary to compress all of the specimens. Steel is the
agreement.
preferred plate material.
38.2 Mechanically convected air oven capable of maintain-
33. Number of Specimens
ing the conditions of 70 6 2 °C.
33.1 Three specimens per sample shall be tested. The value
NOTE 11—While this method does not set limits on the surface area of
reported shall be the mean value of those observed.
the compression plates, the user should be aware that different thermal
conditions can exist for specimens placed at different locations on the
plate.
34. Procedure
34.1 Place the specimen, centered in the line of the axial
39. Test Specimens
load, on the supporting plate of the apparatus. If the product
39.1 The test specimens shall have parallel top and bottom
has one side cored or convoluted, rest this face on the
surfacesandessentiallyperpendicularsides.Itisrecommended
perforated plates.
that the specimens be cut with a band knife or band saw. Die
34.2 Preflex the specimen twice, to a deflection of 75 to
cut specimens have a greater tendency to exhibit edge sticking
80 % of its original thickness, lowering and raising the
(pillowing) after being removed from the compression device.
compression foot at a rate of 250 6 25 mm/min, allowing the
Specimens shall be cut at least 13 mm from any edge that has
compression foot to fully clear the specimen after each preflex.
been exposed to light (see Note 13).
Allow the specimen to rest for a period of 6 6 1 min after the
39.2 Specimens shall be 50 by 50 by 25 mm and core,
final preflex.
unless otherwise specified. Specimens less than 25 mm in
34.3 Bring the compression foot into contact with the thickness shall be plied up, without the use of cement, to a
specimen at a rate of 50 6 5 mm/min and determine the 25-mm thickness.
thickness after applying a contact load of 140 6 14 Pa to the
39.3 Specimens from cored foams shall have a minimum
specimen area (see Note 2). Compress the specimen 50 % of 2
top surface area of 100 cm . The thickness shall be no greater
this thickness at a rate of 50 6 5 mm/min and determine the
than 75 % of the minimum top dimension.
final force, in N, after 60 6 3 s (see Note 8).
39.4 Specimens from uncored molded products 25 mm or
Compression Force Deflection, kPa 5 force, in N
@
less in thickness shall be 50 by 50 mm by full-part thickness
3 2
310 /specimen area, in mm and shall contain the top and bottom skin.
#
D3574 − 17
NOTE 14—Recovery periods greater than 30 to 40 min may be agreed
39.5 Specimensgreaterthan50mminthicknessshallbecut
upon by the purchaser and the supplier.
to 25 mm thickness from the core (see Note 12).
NOTE 12—Specimens from molded products may be tested with one or
42. Calculation
both skins by agreement between the purchaser and the supplier.
NOTE 13—Care should be taken to minimize the exposure of compres-
42.1 Calculate the compression set value by one of the
sion set specimens to visible light. Studies have shown that light can have
following formulas:
a deleterious effect on compression sets. If the specimens are not to be
tested within 24 hours of being cut from the part or block, they should be
NOTE 15—The C calculation is preferred and shall be the calculation
t
covered or be placed in an opaque container or bag.
used when neither C nor C are specified.
t d
40. Number of Specimens
42.1.1 Calculate the constant deflection compression set,
expressed as a percentage of the original thickness, as follows:
40.1 Three specimens per sample shall be tested. The value
reported shall be the mean of those observed.
C 5 @~t 2 t !/t # 3100 (2)
t o f o
where:
41. Procedure
C = compression set expressed as a percentage of the
41.1 Conduct all measurements, conditioning, and recovery t
original thickness,
of the specimens at 23 6 2 °C and in an atmosphere of 50 6
t = original thickness of test specimen, and
o
10 % relative humidity, as specified in 6.1.
t = final thickness of test specimen.
f
41.2 Measure the original thickness of the test specimens in
42.1.2 Calculate the constant deflection compression set,
accordance with the procedure described in Section 8.
expressed as a percentage of the original deflection, as follows:
41.3 Place the test specimens in the compression device and
C 5 @~t 2 t !/~t 2 t !# 3100 (3)
d o f o s
deflect them to 50 6 1%, 75 6 1%, or 90 6 1 % of their
original thickness, or to any other deflection agreed upon
where:
betweenthepurchaserandthesupplier.Spacethespecimensin
C = compression set expressed as a percent of the original
d
the compression device in such a manner that there is at least
deflection,
6 mm of separation between specimens in all directions.
t = original thickness of test specimen,
o
t = thickness of spacer bar used, and
41.4 Within 15 min, place the compression device contain- s
t = final thickness of test specimen.
f
ing deflected specimens into the mechanically convected air
NOTE 16—Approximate conversion of C to C can be calculated by
t d
oven for a period of 22 h.
multiplying the 50 % C by 2, the 75 % C by 1.33, and the 90 % C by
t t t
1.11.
41.5 Afterthe22hperiod,removecompressiondevicefrom
the oven. Immediately remove the specimens from the com-
43. Report
pression device and measure the final thickness in accordance
with the procedure described in Section 8 after allowing them
43.1 Report compression set as C or C , and report deflec-
t d
to recover 30 to 40 min at the temperature and humidity
tion used. Also report any non-standard recovery periods or
conditions specified in 41.1.
sample sizes and whether the sample was cored, uncored
and/or molded.
Blair, G.R., Dawe, B., McEvoy, J., Pask, R., Rusan de Priamus, M., Wright, C.
“The Effect of Visible Light on the Variability of Flexible Foam Compression Sets”
44. Precision and Bias
Center for the Polyurethanes Industry of the American Chemistry Council 2007
Conference Proceedings. 44.1 See Section 151 for Precision and Bias statements.
D3574 − 17
TEST E—TENSILE TEST
45. Scope
45.1 This test method determines the effect of the applica-
tion of a tensile force to foam. Measurements are made for
tensile stress at a predetermined, specified elongation
(optional), tensile strength, and ultimate elongation.
NOTE 17—This standard and ISO 1798 address the same subject matter,
but differ in technical content and results cannot be directly compared
between the two methods.
FIG. 1 Tensile Dumbbell Specimen Dimension Key
46. Apparatus
46.1 Specimens—The specimen for tensile tests shall be
stampedoutwithadieoftheshape(dumbbell)anddimensions
shown in Fig. 2 (D3574 die), or Fig. 3 (Die A of Test Method
D412). The die shall be sharp and free of nicks in order to
prevent leaving ragged edges on the specimen. The ASTM
D412 Die A, shown in Fig. 3, is the preferred die.
46.2 Bench Marker—The marker shall have two parallel
marking edges 1 to 3 mm in thickness and spaced 20 or 25 mm
apart on centers.
46.3 Measurements—The dimensions of the test specimen
FIG. 2 Die for Stamping Tensile Dumbbell Specimens—D3574
shall be determined with a suitable gauge in accordance with
Die
Section 8.
46.4 Machine—Tensile tests shall be conducted on a power-
driven machine complying with the following requirements:
46.4.1 The machine shall be equipped with a load cell or
force measuring device to measure the maximum applied
force. The test speed shall be 500 6 50 mm/min, and shall be
uniform at all times.
46.4.2 Elongation shall be determined by either a device
graduated to 2.5 mm for measuring the elongation, by the use
of a non-contact extensometer, or by crosshead travel (also
referredtoasgripseparation).Extensometersthatclipontothe
FIG. 3 Die for Stamping Tensile Dumbbell Specimens—D412A
specimengenerallyareunsuitableforflexiblefoam.Fortesting
Die
dumbbell specimens, the machine shall have either screw-type
flat plate grips or a type of grip that tightens automatically and
exerts a uniform pressure across the gripping surfaces, increas-
ing as the tension increases to prevent slipping.
48. Number of Specimens
47. Test Specimens 48.1 Three specimens per sample shall be tested. The value
reported shall be the mean value of those observed.
47.1 Thetestspecimensshallbecutfromflatsheetmaterial.
Test specimens shall be from 3 - 14 mm in thickness.The foam
49. Procedure
rise shall be in the thickness direction, unless otherwise agreed
upon by purchaser and supplier. The top and bottom surfaces 49.1 Set the grip separation at a minimum of 62.5 mm for
shall be parallel and free of skin. The cut edges shall be the D3574 die and at a minimum of 75 mm for D412 Die A.
perpendicular to the top surface and be free of ragged edges. Place the dumbbell tabs in the grips of the testing machine,
The length of the tabs can be adjusted to fit machine conditions usingcaretoadjustthemsymmetrically,sothatthetensionwill
provided that all other requirements remain constant.
be distributed uniformly over the cross section. The test shall
TABLE 1 Dimension Tolerances of Tensile Dies
Dimension Units Tolerance D3574 Die D412 Die A
A mm ±1 25.4 25
C mm min 139.7 140
G mm ±1 12.7 14
Hmm ±2 6.4 25
L mm ±2 34.93 59
W mm +0.05, –0.00 12.7 12
D3574 − 17
between the two methods.
be run at a speed of 500 6 50 mm/min, unless otherwise
specified by agreement between purchaser and supplier.
54. Apparatus
49.2 Start the machine and, if measuring elongation by
54.1 Tear resistance shall be measured on a power-driven
bench mark, note continuously the distance between the two
machine, which will indicate the maximum force, by mechani-
bench marks.
cal or electronic means, at which rupture of the specimen takes
49.3 If tensile stress at a predetermined elongation was
place.
specified, record the stress at the specified percent elongation
(it is also acceptable to note the stress at a predetermined
55. Test Specimens
elongation automatically by means of a recording device, or by
55.1 The test specimens shall be a block shape free of skin,
machine software).
voids, and densification lines, as shown in Fig. 4.They shall be
49.4 At rupture, measure or record elongation to the nearest
cut on a saw from sheet material ensuring that the sides are
10 %.
parallel and perpendicular to each other.Anominal 40-mm cut
shall be placed in one side as shown in Fig. 4. Dimension A-B
50. Calculation
can be reduced to the pad thickness. The thickness shall be
determined in accordance with Section 8.
50.1 Calculatethetensilestrengthbydividingthemaximum
breaking force by the original cross-sectional area of the
56. Number of Specimens
specimen.
56.1 Threespecimenspersampleshallbetested.Thevalues
50.2 Calculate the tensile stress by dividing the force at
reported shall be the mean of those tested.
predetermined percent elongation by the original cross-
sectional area of the specimen.
57. Procedure
50.3 Calculate the ultimate elongation, A, by subtracting the
57.1 Clamp the test specimen in the jaws of the testing
original distance between the bench marks from the total
machine, taking care that the jaws grip the specimen properly.
distance between the bench marks at the time of rupture and
Spread the block so that each tab is held in the jaw to pull
expressing the difference as a percentage of the original
acrossthespecimen.Thetestspeedshallbe500 650mm/min,
distance, as follows, or use the grip separations in a similar
unlessotherwisespecifiedbyagreementbetweenthepurchaser
calculation.
and the supplier.Aid the cut in the specimen with a razor blade
A,% 5 @~d 2 d !/d # 3100 (4)
f o o
or knife, so as to keep it in the center of the block (Note 19).
After the rupture of the specimen, or after at least a 50-mm
where:
length is torn, record the maximum force in newtons and note
d = original distance between bench marks, and
o
also the thickness of the specimen (direction A-B).
d = distance between bench marks at the break point.
f
NOTE 19—For foams that will not tear by this method, side by side tear
50.4 The value reported shall be the mean value of all
strength comparisons can be made by testing in accordance with Test
specimens tested.
Method D624, using Type C die. It shall be noted that the D624 Type C
tear test is a tear initiating measurement, as opposed to a tear propagating
51. Report
measurement, as in this block tear test.
51.1 Report the following information:
58. Calculation
51.1.1 Tensile strength in kilopascals.
58.1 Calculate the tear strength from the maximum force
51.1.2 Tensile stress in kilopascals at predetermined elon-
registered on the testing machine and the average thickness of
gation.
the specimen (direction A-B), as follows:
51.1.3 Ultimate elongation, in percent, and whether bench
marks, grip separation or extensometers were used to measure
Tear strength, N/m 5 F/T 310 (5)
elongation.
where:
51.1.4 Crosshead speed, if other than 500 mm/min.
F = force, N, and
T = thickness, mm.
52. Precision and Bias
52.1 See Section 151 for Precision and Bias statements.
TEST F—TEAR RESISTANCE TEST
53. Scope
53.1 This test method covers determination of the tear
propagation resistance of foam. The block method, as
described, measures the tear resistance under the conditions of
this particular test.
NOTE 18—This standard and ISO 8067 address the same subject matter,
but differ in technical content and results cannot be directly compared FIG. 4 Tear Resistance Test Specimens
D3574 − 17
using the equipment specified in Test Method D737. Direct correlations
59. Report
between Test Method D737 and this method have been established,
59.1 Report the following information:
although some modification of the D737 equipment could be necessary.
59.1.1 Tear strength in newtons per metre.
Test Method D3574 air flow times 36 will give an approximate value for
Test Method D737 air flow.
59.1.2 Orientation of specimen.
59.1.3 Crosshead speed, if other than 500 mm/min.
62. Terminology
60. Precision and Bias
62.1 Definitions of Terms Specific to This Standard:
62.1.1 air flow value—the volume of air per second at
60.1 See Section 151 for Precision and Bias statements.
standard temperature and atmospheric pressure required to
TEST G—AIR FLOW TEST
maintain a constant pressure differential of 125 Pa across a
flexible foam specimen approximately 50 by 50 by 25 mm.
61. Scope
62.1.2 air flow parallel to foam rise—the air flow value
61.1 The air flow test measures the ease with which air
obtained when the air enters and leaves the mounted specimen
passes through a cellular structure.Air flow values can be used
parallel to foam rise.
as an indirect measurement of certain cell structure character-
istics. The test consists of placing a flexible foam core 63. Apparatus
specimen in a cavity over a chamber and creating a specified
63.1 A schematic drawing of the apparatus, including the
constant air pressure differential. The rate of flow of air
specimen mounting chamber, manometer, air flow meters,
required to maintain this pressure differential is the air flow
blow meters, blower, and voltage control, is shown in Fig. 5.
value. This test is normally for slab foam products or for the
63.2 Chamber, consisting of a pot approximately 130 mm in
core materials of molded products.Alternative methods can be
diameter and 150 mm high, with provision for mounting the
used to measure air flow through molded skins or extremely
foam specimen and fittings for the manometer and air exhaust.
high air flow products (see Note 21).
NOTE 20—This standard is identical to ISO 7231.
NOTE 21—For measuring air flow of products, such as very tight
Gummaraju, R.V., Pask, R.F., Koller, H.J., Wujcik, S.E., and Reimann, K.A.,
viscoelastic foams or very high air flow foams, which can have air flows
“Evaluation, Modification and Adaptation of an Airflow Test Method for Polyure-
beyond the range of this method, very good success has been achieved by thane Foams,” Journal of Cellular Plastics , May/June 2001.
FIG. 5 Air Flow Apparatus Schematic Diagram
D3574 − 17
The specimen mount cavity shall be 50.0 6 0.5 by 50.0 6 0.5 65. Procedure
by 25.0 6 0.5 mm in size. Four foam support vanes approxi-
65.1 Measure each specimen in accordance with the proce-
mately 1 mm thick and 12.5 mm high shall be placed under the
dure described in Section 8 to verify the specimen size.
openingtopreventthefoamfrombeingpulledintothevacuum
65.2 Insert the specimen into the test cavity. Make sure that
chamber. The vanes shall be spaced 12.5 mm on center from
a good air seal is obtained along all edges. The top of the
eachotherandalsocenteredrelativetothebottomofthecavity
specimen shall be flush with the top of the test chamber.
opening. The manometer fitting shall enter a 1-mm hole
midway along the side of the chamber. A 25-mm pipe fitting
65.3 With all valves closed, adjust the voltage control of the
shallbeusedastheexhaustoutletfromthecenterofthebottom
apparatus to 30 %.
of the chamber.
65.4 Open one flow-control valve slowly until a pressure
63.3 Manometer, calibrated from 0 to 250 Pa and having an
differential of 100 to 150 Pa is obtained. Adjust the voltage
accuracy of 62 %, is required.An inclined oil manometer with
controlcarefullytoobtainapressuredifferentialof125 61Pa.
graduations of 2 Pa is recommended. A level mounted on the
65.5 After this pressure differential has been maintained for
manometer shall be used to ensure that the proper degree of
at least 10 s, read the scale of the flow meter.
inclination from the horizontal is maintained. Traps shall be
provided to prevent indicating fluid from being accidentally
65.6 If this reading is off-scale or less than 10 % of full
drawn into the chamber. Appendix X5 describes a suggested
scale, close that flow-control valve and open a more appropri-
method for the verification of the inclined oil manometer. The
ate one. Repeat this process until the proper manometer
manometer can alternatively be replaced with a 0-250 Pa
reading and air flow is achieved.
magnehelic gauge with graduations of 5 Pa.
65.7 The air flow value shall be obtained from the flow
63.4 Flow Meters and Blower—Low-pressure-drop air flow
meter scale directly, estimated from a calibration chart, or
meters accurate to 62 % shall be used for air-flow measure-
calculated with a factor depending on the calibration system.
ments.Agivenflowmetershallnotbeusedforvalueslessthan
10 % of full scale.Air flow meters with at least 250-mm scales
66. Report
are recommended. Since the flow meter calibration is
66.1 Report the following information:
temperature-and pressure-dependent, the use of the apparatus
66.1.1 Mean air flow value in cubic metres per minute for
under ambient conditions can result in erroneous readings. In
each location and orientation.
cases of dispute, the apparatus shall be used under standard
66.1.2 Dimensions of the specimens.
conditions of 23°C and 100 kPa (1 atm pressure), or else a
66.1.3 Dimension of the mount cavity of the apparatus.
suitable calibration correction applied. Flow meters that range
from 0 to 0.01 m /s will cover a wide range of foam cell
67. Precision and Bias
structures, but a lesser range can be used. Actual flow is
adjusted by a combination of valve restriction and blower
67.1 See Section 151 for Precision and Bias statements.
speed.Thetwo-wayvalvesshallbemountedontheoutputside
of the flow meter to maintain the pressure drop across the flow TEST H—RESILIENCE (BALL REBOUND) TEST
meter constant at any given flow level.Avacuum cleaner type
unit shall be used for an exhaust blower. 68. Scope
63.5 Leak Test—To check the apparatus for leaks, the
68.1 This test consists of dropping a steel ball on a foam
specimenmountcavityshallbesealedwithmaskingtape.With
specimen and noting the height of rebound.
all valves closed, turn on the exhaust blower to approximately
NOTE 22—This standard is identical to ISO 8307.
⁄3 power and observe any movement of the manometer. The
manometer reading, if any, shall not exceed 1 Pa after a 30-s
69. Apparatus
waiting period. Next, open the valve very slightly for the
lowest range flow meter reading. The flow shall be essentially 69.1 The ball rebound tester shall consist of a 40 6 4-mm
zero, as evidenced by a less than 3-mm movement of the air inside diameter vertical clear plastic (such as acrylic) tube, into
flow meter float from its static position. For the equipment to which a 16.0 6 0.2-mm diameter steel ball, weighing 16.3 6
perform satisfactorily over its entire range, the requirements
0.2 g, is released by a magnet or other device. The steel ball
for both parts of the leak test must be met. must be released so that it falls without rotation. Centering of
the ball is assured by a recess at the base of the magnet. The
64. Test Specimens
height of drop shall be 500 mm. Since it is most convenient to
64.1 The test specimens shall be parallelepiped cut to fit the
note the position of the top of the ball on rebound, the top of
mount cavity of the apparatus. A cavity 50 by 50 mm requires
the ball shall be 516 mm above the surface of the foam. Thus,
aspecimen51.0 60.3by51.0 60.3by25.0 60.5mminsize.
“zero” rebound shall be 16.0 6 0.2 mm (diameter of ball)
A band saw with a movable table and a double-bevel knife-
above the specimen surface. The scale on the tube shall be
edge blade is recommended for cutting the specimens.
scribed directly i
...

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: D3574 − 16 D3574 − 17
Standard Test Methods for
Flexible Cellular Materials—Slab, Bonded, and Molded
Urethane Foams
This standard is issued under the fixed designation D3574; 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 These test methods apply to slab, bonded, and molded flexible cellular products known as urethane foams. Urethane foam
is generally defined as an expanded cellular product produced by the interaction of active hydrogen compounds, water, and
isocyanates.
1.2 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.
1.3 The values stated in SI units are to be regarded as standard.
NOTE 1—There is no known ISO equivalent to this standard, however certain test methods in this standard have similar or equivalent ISO standards
and are listed in the scope of the individual test method sections.
2. Referenced Documents
2.1 ASTM Standards:
D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension
D624 Test Method for Tear Strength of Conventional Vulcanized Rubber and Thermoplastic Elastomers
D737 Test Method for Air Permeability of Textile Fabrics
D3576 Test Method for Cell Size of Rigid Cellular Plastics
D3675 Test Method for Surface Flammability of Flexible Cellular Materials Using a Radiant Heat Energy Source
E162 Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
E662 Test Method for Specific Optical Density of Smoke Generated by Solid Materials
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 bonded foam—a product produced by the adhesion of small pieces of urethane foam to each other with a suitable bonding
agent.
3.1.2 core—the internal portion of a molded part, free of skin.
3.1.3 cored foam—a flexible cellular material containing a multiplicity of holes (usually, but not necessarily, cylindrical in
shape), molded or cut into the material in some pattern, normally perpendicular to the foam rise direction, and extending part or
all the way through the piece.
3.1.4 convoluted foam—a flexible cellular material specially cut into sheets with “egg carton”-like dimples. The dimple peaks
and bases can have varied shapes and dimensions.
3.1.5 flexible cellular product—a cellular organic polymeric material that will not rupture when a specimen 200 by 25 by 25
mm is bent around a 25-mm diameter mandrel at a uniform rate of one lap in 5 s at a temperature between 18 and 29°C.
These test methods are under the jurisdiction of ASTM Committee D20 on Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular Materials -
Plastics and Elastomers.
Current edition approved Nov. 1, 2016March 1, 2017. Published January 2017March 2017. Originally approved in 1977. Last previous edition approved in 20112016 as
D3574 – 11.D3574 – 16. DOI: 10.1520/D3574-16.10.1520/D3574-17.
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
D3574 − 17
3.1.6 molded foam—a cellular product having the shape of the enclosed chamber in which it is produced by foaming.
3.1.7 skin—the smooth surface layer of a molded foam product, formed by contact with the mold or surfaces.
3.1.8 slab—a section of foam that is cut from the internal portion of a large bun.
3.1.9 urethane foam—a flexible cellular product produced by the interaction of active hydrogen compounds, water, and
isocyanates.
3.1.10 viscoelastic foam—a specially formulated urethane foam characterized by having slow recovery, low resilience, and high
hysteresis loss.
3.1.11 cell count—a measurement used to characterize different types of foams based on the size of the individual cells in the
foam matrix, typically expressed as either average cell diameter or as the number of cells per linear distance. For measuring cell
counts, see Test Method D3576.
3.1.12 clickability—the ability of a flexible cellular material to recover from the pinching effects of die cutting.
4. Summary of Test Methods
4.1 Unless otherwise specifically stated and agreed upon by the purchaser and the supplier, all tests shall be made in accordance
with the methods specified in Sections 9 – 150, which include test procedures for the following:
Tests: Sections
Test A Density Test 9 – 15
Test B Indentation Force Deflection Test—Specified 16 – 22
Deflection (IFD)
Test B Indentation Residual Gauge Length Test— 23 – 29
Specified
Force (IRGL)
Test C Compression Force Deflection Test 30 – 36
Test D Constant Deflection Compression Set Test 37 – 44
Test E Tensile Test 45 – 52
Test F Tear Resistance Test 53 – 60
Test G Air Flow Test 61 – 67
Test H Resilience (Ball Rebound) Test 68 – 75
Test I Static Force Loss Test at Constant Deflection 77 – 85
Test I Dynamic Fatigue Test by Roller Shear at Con- 86 – 94
stant Force
Test I Dynamic Fatigue Test by Constant Force 95 – 103
Pounding
Test I Dynamic Fatigue Test for Carpet Cushion 104 – 112
Test I Dynamic Fatigue Test by Constant Deflection 113 – 121
Pounding
Aging Test J Steam Autoclave Aging 122 – 127
Aging Test K Dry Heat Aging 128 – 133
Aging Test L Wet Heat Aging 134 – 139
Test M Recovery Time 140 – 145
Test N Hysteresis Loss 146 – 150
Appendixes:
X1. Suggested Method for Specifying Flexible Urethane Foams
X2. Suggested Method of Construction for a Roller Shear Dynamic Flex
Fatigue Apparatus
X3. Definitions of Terms Used to Describe the Force-Deflection Curve of
Flexible Urethane Foam
X4. Suggested Tests for Determining Combustibility of Flexible Urethane
Foam. (The combustion tests are given for informational purposes only
and are not part of the standard.)
X5. Suggested Method for the Verification of an Inclined Oil Manometer
5. Significance and Use
5.1 The test procedures provide a standard method of obtaining data for research and development, quality control, acceptance
and rejection under specifications, and special purposes.
5.2 The data obtained by these test methods are applicable to the material under conditions of the particular test and are not
necessarily the same as obtained in other environments in use.
6. General Test Conditions
6.1 Tests shall be entirely conducted at 23 6 2 °C and 50 6 10 % relative humidity, unless otherwise specified in the individual
test method. The product shall be conditioned, undeflected and undistorted, at 23 6 2 °C and 50 6 10 % relative humidity, for at
least 12 h before being tested, unless otherwise specified in the individual test method.
6.2 It is recommended for referee purposes that all tests be performed seven days or more after the foam has been manufactured.
D3574 − 17
6.3 For mechanical tests, it is advisable to carefully select the proper load cell for each test. It is recommended that the expected
load for any individual test falls within 10-90 % of the load cell capacity.
7. Sampling
7.1 When possible, the completed manufactured product shall be used for the test specified. Representative samples of the lot
being examined shall be selected at random, as required.
7.2 When it is necessary or advisable to obtain specimens from the articles, as in those cases where the entire sample is not
required or adaptable for testing, the method of cutting and the exact position from which specimens are to be taken shall be
specified. The density and the state of cure can vary in different parts of the finished product, especially if the article is of
complicated shape or of varying thickness, and these factors affect the physical properties of the specimens. Also, the density is
affected by the number of cut surfaces on the specimen. If a test specimen is die cut, ensure that the sides are not concave and allow
sufficient time for complete recovery of the thickness across the full width of the specimen before testing.
7.3 When the finished molded product does not lend itself to testing or to the taking of specimens because of complicated shape,
small size, metal or fabric inserts, adhesion to metal, or other reasons, molded test slabs, as agreed upon between the purchaser
and the supplier, shall be prepared.
7.4 When differences in test results arise due to the difficulty in obtaining suitable specimens from the finished parts, the
purchaser and the supplier shall agree upon an acceptable location from which to take the specimen.
8. Measurement of Test Specimens
8.1 Measure the length and width with a scale, tape, or caliper gauge. Take care not to distort the foam.
8.2 Measure thickness up to and including 25 mm using a height or electronic display gauge with a minimum foot area of 650
mm . Hold the pressure of the gauge foot to a maximum of 800 Pa (see Note 2). Thicknesses over 25 mm shall be measured with
a height or electronic display gauge, a sliding caliper gauge, or as specified in 8.1. When a sliding caliper gauge is employed, make
the gauge setting with the gauge out of contact with the foam. Pass the specimen through the previously set gauge; the proper
setting shall be the one when the measuring faces of the gauge contact the surfaces of the specimen without compressing it.
NOTE 2—For soft foams having compression force deflection values less than 1.65 kPa, the pressure on the gauge or compression foot shall not exceed
200 Pa.
8.3 The scale, tape, or gauge shall be graduated so as to permit measurements within 61 % of the dimensions to be measured.
8.4 Unless otherwise specified, results shall be the mean of the measurements.
TEST A—DENSITY TEST
9. Scope
9.1 This test method covers determination of the density of uncored foam by calculation from the mass and volume of the
specimen. The density value thus obtained applies only to the immediate area from which the specimen has been taken. It does
not necessarily relate to the bulk density of the entire molded pad.
NOTE 3—This standard is equivalent to ISO 845.
10. Test Specimen
10.1 Core Density—A representative specimen of regular shape, circular or square without skins or densification lines, not less
3 3
than 10,000 mm (~0.61 in. ) in volume, shall be cut from a portion free of voids and defects and as near as possible to the section
from which the tension and tear specimens were taken.
10.2 Section Density—A representative specimen with skins on the top and bottom surface measuring at least 0.1 m in area by
full-part thickness, shall be cut from an area free of voids and defects and as near as possible to the location from which the tension
and tear specimens were taken. When these dimensions are not possible, the largest representative portion as agreed upon between
the purchaser and the supplier, shall be used.
11. Number of Specimens
11.1 One specimen shall be tested, unless otherwise agreed upon by the purchaser and the supplier.
12. Procedure
12.1 Determine the mass of the specimen to a precision of 61 %.
12.2 Determine the dimensions of the specimen in accordance with Section 8, and calculate the volume.
D3574 − 17
13. Calculation
13.1 Calculate the density in kilograms per cubic metre as follows:
Density 5 M/V 310 (1)
where:
M = mass of specimen, g, and
V = volume of specimen, mm .
14. Report
14.1 Report the following information:
14.1.1 Density to the nearest 0.1 kg/m , and
14.1.2 Type of specimen, core or section.
15. Precision and Bias
15.1 See Section 151 for Precision and Bias statements.
TEST B —INDENTATION FORCE DEFLECTION TEST—SPECIFIED DEFLECTION (IFD)
16. Scope
16.1 This will be known as the indentation force deflection test and the results as the IFD values. This test consists of measuring
the force necessary to produce designated indentations in the foam product, for example, indentations at 25 and 65 % deflections.
(See Appendix X3 for additional information).
NOTE 4—This standard and ISO 2439 address the same subject matter, but differ in technical content and results cannot be directly compared between
the two methods.
17. Apparatus
17.1 An apparatus having a flat circular indenter foot 200 +3/–0 mm in diameter connected by means of a swivel joint capable
of accommodating the angle of the sample to a force-measuring device and mounted in such a manner that the product or specimen
can be deflected at a speed of 50 to 250 mm/min. The apparatus shall be arranged to support the specimen on a level horizontal
plate which is perforated with approximately 6.5-mm holes on approximately 20-mm centers to allow for rapid escape of air during
the test. Special supports for contoured molded pads shall be perforated in the same manner as the flat plate, unless otherwise
agreed upon between the purchaser and the supplier. Pads longer than the base plate shall be supported from distortion at the 4.5-N
contact force (see 20.3).
NOTE 5—Equipment design and test fixturing can affect the results of this test. As an example, load cells placed below the support plate can experience
a bridging effect that likely does not occur in equipment which has the load cell mounted above the indenter foot.
18. Test Specimen
18.1 The test specimen shall consist of the entire product sample or a suitable portion of it, except that in no case shall the
specimen have dimensions less than 380 by 380 by 100 mm. If specimens are less than (or different from) 100 mm in thickness,
the thickness shall be noted on the test report.
18.2 The IFD values for molded products are dependent on the specimen dimensions. Higher values are generally obtained for
specimens that retain all molded surfaces.
19. Number of Specimens
19.1 One specimen shall be tested, unless otherwise agreed upon by the purchaser and the supplier.
20. Procedure
20.1 Place the test specimen in position on the supporting plate of the apparatus. If the product has one side cored or convoluted,
this face shall rest on the perforated plate. The specimen position shall be such that, whenever practicable, the indentation will be
made at the center of the specimen, except when another location is agreed upon by the purchaser and the supplier.
20.2 Preflex the test area twice to a deflection of 75 to 80 % of the full-part thickness, lowering and raising the indenter foot
at a rate of 250 6 25 mm/min, allowing the indenter to fully clear the top of the specimen after each preflex. For fatigue tests,
or in case repeat testing proves necessary, mark the location of the test area by circumscribing the indenter foot with a pen. Allow
the specimen to rest for 6 6 1 min after the final preflex.
20.3 Bring the indenter foot into contact with the specimen at a rate of 50 6 5 mm/min and determine the thickness while
applying a contact force of 4.5 6 0.5 N to the indenter foot. For super-soft foam, with a 25 % IFD less than 40 N, a reduction of
pressure on the indenter foot shall be allowed. Sufficient contact force to make an accurate initial thickness measurement is
D3574 − 17
required. Indent the specimen at a rate of 50 6 5 mm/min 25 % of this thickness and observe the force in newtons after 60 6 3
s. Without removing the specimen, increase the deflection to 65 % deflection, allowing the force to drift while maintaining the 65 %
deflection, and again observe the force in newtons after 60 6 3 s.
21. Report
21.1 Report the force in newtons required for 25 % and 65 % indentation or other indentations (see Note 6). These figures are
known as the 25 % and 65 % IFD values, respectively. Report length, width, and thickness of the specimen, if non-standard, and
the ratio of 65 % to 25 % IFD values (that is, support factor, see Appendix X3).
NOTE 6—Indentation deflection tests, other than 25 % and 65 %, as well as a 25 % return value (25 % RT), may be specified as agreed upon between
the purchaser and the supplier. Alternative or additional deflections shall be performed as described in 20.3.
22. Precision and Bias
22.1 See Section 151 for Precision and Bias statements.
TEST B —INDENTATION RESIDUAL GAUGE LENGTH TEST—SPECIFIED FORCE (IRGL)
23. Scope
23.1 Cellular foam products have traditionally been checked for indentation force deflection by determining the force required
to effect a 25 % deflection. In seating, on the other hand, the interest is in determining how thick the padding is under the average
person. Three measurements are called for to meet the requirements of this test method. The force deflection is determined by
measuring the thickness of the pad under a fixed force of 4.5 N, 110 N, and 220 N, with a 200 + 3/– 0 mm circular indenter foot.
23.2 This determination shall be known as the Indentation Residual Gauge Length and the measurements as the IRGL values.
NOTE 7—This standard and ISO 2439 address the same subject matter, but differ in technical content; and results cannot be directly compared between
the two methods.
24. Apparatus
24.1 An apparatus having a flat circular indenter foot 200 +3/–0 mm in diameter, connected with a swivel joint for applying
forces of 4.5 N, 110 N, 220 N and 330 N, shall be mounted over a level horizontal platform that is perforated with approximately
6.5-mm holes on approximately 20-mm centers to allow for rapid escape of air during the test. The distance between the indenter
foot and the platform shall be variable to indent the specimen at a speed of 50 to 250 mm/min for thickness measurements. The
apparatus shall be equipped with a device for measuring the distance between plates.
24.2 Special supports for contoured molded pads shall be perforated and agreed upon between the purchaser and the supplier.
Pads longer than the base plate shall be supported from distortion at the 4.5-N contact force (see 27.2).
25. Test Specimen
25.1 When possible, the finished manufactured product shall be used. In the case of tapered cushions, the location of the area
for measurement is to be agreed upon between the purchaser and the supplier. In case a finished part is not feasible for test, 380
by 380-mm specimens of an average thickness are to be cut from the cushion.
25.2 The IRGL values for molded products are dependent on the specimen dimensions. Different values are generally obtained
for specimens that retain all molded surfaces.
26. Number of Specimens
26.1 One specimen shall be tested, unless otherwise agreed upon by the purchaser and the supplier.
27. Procedure
27.1 Test the whole test specimen or a minimum area of 380 by 380 mm. Position the specimen in the test apparatus with any
cored or convoluted surfaces resting against the perforated bottom plate. Preflex the specimen twice with a 330 N force, raising
and lowering the indenter foot at 200 6 20 mm/min, allowing the indenter foot to fully clear the top of the specimen after each
preflex. Allow the specimen to rest for 6 6 1 min after the final preflex.
27.2 At a rate of 50 6 5 mm/min, bring the indenter foot into contact with and determine the thickness of the specimen, in mm,
with a 4.5 6 0.5-N load on the indenter foot.
27.3 Apply the 110-N force at 50 6 5 mm/min with the indenter foot until the force is carried by the specimen. Determine the
thickness, in mm, at 110 N after maintaining the force for 60 6 3 s.
27.4 Without removing the specimen, apply the 220-N force at 50 6 5 mm/min with the indenter foot until the force is carried
by the specimen. Determine the thickness, in mm, at 220 N after maintaining the force for 60 6 3 s.
D3574 − 17
28. Report
28.1 Report the specimen thickness, in mm, at 4.5 N instantaneously and at 110 N and 220 N after 60 6 3 s. These figures are
known as the IRGL values, respectively. Report the length, width, and thickness of the specimen.
29. Precision and Bias
29.1 See Section 151 for Precision and Bias statements.
TEST C—COMPRESSION FORCE DEFLECTION TEST
30. Scope
30.1 This test consists of measuring the force necessary to produce a 50 % compression over the entire top area of the foam
specimen.
NOTE 8—This standard and ISO 3386 address the same subject matter, but differ in technical content; and results cannot be directly compared between
the two methods.
NOTE 9—Compression force deflection tests other than at 50 % may be specified, as agreed upon between the purchaser and the supplier, following
the procedure in Section 34.
31. Apparatus
31.1 An apparatus having a flat, fixed compression foot, larger than the specimen to be tested, connected to a force-measuring
device and mounted in a manner such that the product or specimen can be deflected at a speed of 50 to 500 mm/min. The apparatus
shall be arranged to support the specimen on a level horizontal plate that is perforated with approximately 6.5-mm holes on
approximately 20-mm centers to allow for rapid escape of air during the test.
32. Test Specimens
32.1 The test specimens shall have parallel top and bottom surfaces and vertical sides. The thickness shall be no greater than
75 % of the minimum top dimension. The standard specimen shall be 50 mm by 50 mm by 25 mm in thickness. Larger specimens
are preferable, where possible.
32.2 Specimens shall be a minimum of 2500 mm in surface area and have a minimum thickness of 20 mm.
32.3 Unless otherwise agreed upon by purchaser and supplier, specimens from molded parts shall be cut from the core material
at least 10 mm below the molded surface. Note in the report if the specimens contain one or more molded surfaces resulting from
insufficient core material or contractual agreement.
33. Number of Specimens
33.1 Three specimens per sample shall be tested. The value reported shall be the mean value of those observed.
34. Procedure
34.1 Place the specimen, centered in the line of the axial load, on the supporting plate of the apparatus. If the product has one
side cored or convoluted, rest this face on the perforated plates.
34.2 Preflex the specimen twice, to a deflection of 75 to 80 % of its original thickness, lowering and raising the compression
foot at a rate of 250 6 25 mm/min, allowing the compression foot to fully clear the specimen after each preflex. Allow the
specimen to rest for a period of 6 6 1 min after the final preflex.
34.3 Bring the compression foot into contact with the specimen at a rate of 50 6 5 mm/min and determine the thickness after
applying a contact load of 140 6 14 Pa to the specimen area (see Note 2). Compress the specimen 50 % of this thickness at a rate
of 50 6 5 mm/min and determine the final force, in N, after 60 6 3 s (see Note 8).
3 2
Compression Force Deflection, kPa 5 force, in N 310 /specimen area, in mm
@ #
35. Report
35.1 Report the thickness after contact force, the 50 % compression deflection value in kilopascals, and the dimensions of
non-standard specimens. Indicate if the sample was cored or convoluted. Report if the specimens contained one or more molded
surfaces.
36. Precision and Bias
36.1 See Section 151 for Precision and Bias statements.
D3574 − 17
TEST D—CONSTANT DEFLECTION COMPRESSION SET TEST
37. Scope
37.1 This test method consists of deflecting the foam specimen to a specified deflection, exposing it to specified conditions of
time and temperature and measuring the change in the thickness of the specimen after a specified recovery period.
NOTE 10—This standard and ISO 1856 address the same subject matter, but differ in technical content and results cannot be directly compared between
the two methods.
38. Apparatus
38.1 Compression Device, consisting of two or more flat plates arranged so the plates are held parallel to each other by bolts
or clamps and the space between the plates is adjustable to the required deflection thickness by means of spacers. The plates shall
be constructed from steelmetal in composition and have sufficient stiffness to ensure that they are not deflected under the force
necessary to compress all of the specimens. Steel is the preferred plate material.
38.2 Mechanically convected air oven capable of maintaining the conditions of 70 6 2 °C.
NOTE 11—While this method does not set limits on the surface area of the compression plates, the user should be aware that different thermal conditions
can exist for specimens placed at different locations on the plate.
39. Test Specimens
39.1 The test specimens shall have parallel top and bottom surfaces and essentially perpendicular sides. It is recommended that
the specimens be cut with a band knife or band saw. Die cut specimens have a greater tendency to exhibit edge sticking (pillowing)
after being removed from the compression device. Specimens shall be cut at least 13 mm from any edge that has been exposed
to light (see Note 13).
39.2 Specimens shall be 50 by 50 by 25 mm and core, unless otherwise specified. Specimens less than 25 mm in thickness shall
be plied up, without the use of cement, to a 25-mm thickness.
39.3 Specimens from cored foams shall have a minimum top surface area of 100 cm . The thickness shall be no greater than
75 % of the minimum top dimension.
39.4 Specimens from uncored molded products 25 mm or less in thickness shall be 50 by 50 mm by full-part thickness and shall
contain the top and bottom skin.
39.5 Specimens greater than 50 mm in thickness shall be cut to 25 mm thickness from the core (see Note 12).
NOTE 12—Specimens from molded products may be tested with one or both skins by agreement between the purchaser and the supplier.
NOTE 13—Care should be taken to minimize the exposure of compression set specimens to visible light. Studies have shown that light can have a
deleterious effect on compression sets. If the specimens are not to be tested within 24 hours of being cut from the part or block, they should be covered
or be placed in an opaque container or bag.
40. Number of Specimens
40.1 Three specimens per sample shall be tested. The value reported shall be the mean of those observed.
41. Procedure
41.1 Conduct all measurements, conditioning, and recovery of the specimens at 23 6 2 °C and in an atmosphere of 50 6 10 %
relative humidity, as specified in 6.1.
41.2 Measure the original thickness of the test specimens in accordance with the procedure described in Section 8.
41.3 Place the test specimens in the compression device and deflect them to 50 6 1 %, 75 6 1 %, or 90 6 1 % of their original
thickness, or to any other deflection agreed upon between the purchaser and the supplier. Space the specimens in the compression
device in such a manner that there is at least 6 mm of separation between specimens in all directions.
41.4 Within 15 min, place the compression device containing deflected specimens into the mechanically convected air oven for
a period of 22 h.
41.5 After the 22 h period, remove compression device from the oven. Immediately remove the specimens from the
compression device and measure the final thickness in accordance with the procedure described in Section 8 after allowing them
to recover 30 to 40 min at the temperature and humidity conditions specified in 41.1.
NOTE 14—Recovery periods greater than 30 to 40 min may be agreed upon by the purchaser and the supplier.
42. Calculation
42.1 Calculate the compression set value by one of the following formulas:
NOTE 15—The C calculation is preferred and shall be the calculation used when neither C nor C are specified.
t t d
Blair, G.R., Dawe, B., McEvoy, J., Pask, R., Rusan de Priamus, M., Wright, C. “The Effect of Visible Light on the Variability of Flexible Foam Compression Sets” Center
for the Polyurethanes Industry of the American Chemistry Council 2007 Conference Proceedings.
D3574 − 17
42.1.1 Calculate the constant deflection compression set, expressed as a percentage of the original thickness, as follows:
C 5 @~t 2 t !/t # 3100 (2)
t o f o
where:
C = compression set expressed as a percentage of the original thickness,
t
t = original thickness of test specimen, and
o
t = final thickness of test specimen.
f
42.1.2 Calculate the constant deflection compression set, expressed as a percentage of the original deflection, as follows:
C 5 @~t 2 t !/~t 2 t !# 3100 (3)
d o f o s
where:
C = compression set expressed as a percent of the original deflection,
d
t = original thickness of test specimen,
o
t = thickness of spacer bar used, and
s
t = final thickness of test specimen.
f
NOTE 16—Approximate conversion of C to C can be calculated by multiplying the 50 % C by 2, the 75 % C by 1.33, and the 90 % C by 1.11.
t d t t t
43. Report
43.1 Report compression set as C or C , and report deflection used. Also report any non-standard recovery periods or sample
t d
sizes and whether the sample was cored, uncored and/or molded.
44. Precision and Bias
44.1 See Section 151 for Precision and Bias statements.
D3574 − 17
TEST E—TENSILE TEST
45. Scope
45.1 This test method determines the effect of the application of a tensile force to foam. Measurements are made for tensile
stress at a predetermined, specified elongation (optional), tensile strength, and ultimate elongation.
NOTE 17—This standard and ISO 1798 address the same subject matter, but differ in technical content and results cannot be directly compared between
the two methods.
46. Apparatus
46.1 Specimens—The specimen for tensile tests shall be stamped out with a die of the shape (dumbbell) and dimensions shown
in Fig. 2 (D3574 die), or Fig. 3 (Die A of Test Method D412). The die shall be sharp and free of nicks in order to prevent leaving
ragged edges on the specimen. The ASTM D412 Die A, shown in Fig. 3, is the preferred die.
46.2 Bench Marker—The marker shall have two parallel marking edges 1 to 3 mm in thickness and spaced 20 or 25 mm apart
on centers.
46.3 Measurements—The dimensions of the test specimen shall be determined with a suitable gauge in accordance with Section
8.
46.4 Machine—Tensile tests shall be conducted on a power-driven machine complying with the following requirements:
46.4.1 The machine shall be equipped with a load cell or force measuring device to measure the maximum applied force. The
test speed shall be 500 6 50 mm/min, and shall be uniform at all times.
46.4.2 Elongation shall be determined by either a device graduated to 2.5 mm for measuring the elongation, by the use of a
non-contact extensometer, or by crosshead travel (also referred to as grip separation). Extensometers that clip on to the specimen
generally are unsuitable for flexible foam. For testing dumbbell specimens, the machine shall have either screw-type flat plate grips
or a type of grip that tightens automatically and exerts a uniform pressure across the gripping surfaces, increasing as the tension
increases to prevent slipping.
47. Test Specimens
47.1 The test specimens shall be cut from flat sheet material. Test specimens shall be from 3 - 14 mm in thickness. The foam
rise shall be in the thickness direction, unless otherwise agreed upon by purchaser and supplier. The top and bottom surfaces shall
be parallel and free of skin. The cut edges shall be perpendicular to the top surface and be free of ragged edges. The length of the
tabs can be adjusted to fit machine conditions provided that all other requirements remain constant.
48. Number of Specimens
48.1 Three specimens per sample shall be tested. The value reported shall be the mean value of those observed.
49. Procedure
49.1 Set the grip separation at a minimum of 62.5 mm for the D3574 die and at a minimum of 75 mm for D412 Die A. Place
the dumbbell tabs in the grips of the testing machine, using care to adjust them symmetrically, so that the tension will be distributed
uniformly over the cross section. The test shall be run at a speed of 500 6 50 mm/min, unless otherwise specified by agreement
between purchaser and supplier.
49.2 Start the machine and, if measuring elongation by bench mark, note continuously the distance between the two bench
marks.
49.3 If tensile stress at a predetermined elongation was specified, record the stress at the specified percent elongation (it is also
acceptable to note the stress at a predetermined elongation automatically by means of a recording device, or by machine software).
49.4 At rupture, measure or record elongation to the nearest 10 %.
50. Calculation
50.1 Calculate the tensile strength by dividing the maximum breaking force by the original cross-sectional area of the specimen.
TABLE 1 Dimension Tolerances of Tensile Dies
Dimension Units Tolerance D3574 Die D412 Die A
A mm ±1 25.4 25
C mm min 139.7 140
G mm ±1 12.7 14
H mm ±2 6.4 25
L mm ±2 34.93 59
W mm +0.05, –0.00 12.7 12
D3574 − 17
FIG. 1 Tensile Dumbbell Specimen Dimension Key
FIG. 2 Die for Stamping Tensile Dumbbell Specimens—D3574 Die
FIG. 3 Die for Stamping Tensile Dumbbell Specimens—D412A Die
50.2 Calculate the tensile stress by dividing the force at predetermined percent elongation by the original cross-sectional area
of the specimen.
50.3 Calculate the ultimate elongation, A, by subtracting the original distance between the bench marks from the total distance
between the bench marks at the time of rupture and expressing the difference as a percentage of the original distance, as follows,
or use the grip separations in a similar calculation.
A,%5 @~d 2 d !/d # 3100 (4)
f o o
where:
d = original distance between bench marks, and
o
d = distance between bench marks at the break point.
f
50.4 The value reported shall be the mean value of all specimens tested.
51. Report
51.1 Report the following information:
51.1.1 Tensile strength in kilopascals.
51.1.2 Tensile stress in kilopascals at predetermined elongation.
51.1.3 Ultimate elongation, in percent, and whether bench marks, grip separation or extensometers were used to measure
elongation.
51.1.4 Crosshead speed, if other than 500 mm/min.
52. Precision and Bias
52.1 See Section 151 for Precision and Bias statements.
D3574 − 17
TEST F—TEAR RESISTANCE TEST
53. Scope
53.1 This test method covers determination of the tear propagation resistance of foam. The block method, as described,
measures the tear resistance under the conditions of this particular test.
NOTE 18—This standard and ISO 8067 address the same subject matter, but differ in technical content and results cannot be directly compared between
the two methods.
54. Apparatus
54.1 Tear resistance shall be measured on a power-driven machine, which will indicate the maximum force, by mechanical or
electronic means, at which rupture of the specimen takes place.
55. Test Specimens
55.1 The test specimens shall be a block shape free of skin, voids, and densification lines, as shown in Fig. 4. They shall be
cut on a saw from sheet material ensuring that the sides are parallel and perpendicular to each other. A nominal 40-mm cut shall
be placed in one side as shown in Fig. 4. Dimension A-B can be reduced to the pad thickness. The thickness shall be determined
in accordance with Section 8.
56. Number of Specimens
56.1 Three specimens per sample shall be tested. The values reported shall be the mean of those tested.
57. Procedure
57.1 Clamp the test specimen in the jaws of the testing machine, taking care that the jaws grip the specimen properly. Spread
the block so that each tab is held in the jaw to pull across the specimen. The test speed shall be 500 6 50 mm/min, unless otherwise
specified by agreement between the purchaser and the supplier. Aid the cut in the specimen with a razor blade or knife, so as to
keep it in the center of the block (Note 19). After the rupture of the specimen, or after at least a 50-mm length is torn, record the
maximum force in newtons and note also the thickness of the specimen (direction A-B).
NOTE 19—For foams that will not tear by this method, side by side tear strength comparisons can be made by testing in accordance with Test Method
D624, using Type C die. It shall be noted that the D624 Type C tear test is a tear initiating measurement, as opposed to a tear propagating measurement,
as in this block tear test.
58. Calculation
58.1 Calculate the tear strength from the maximum force registered on the testing machine and the average thickness of the
specimen (direction A-B), as follows:
Tear strength, N/m5 F/T 310 (5)
where:
F = force, N, and
T = thickness, mm.
59. Report
59.1 Report the following information:
59.1.1 Tear strength in newtons per metre.
59.1.2 Orientation of specimen.
59.1.3 Crosshead speed, if other than 500 mm/min.
60. Precision and Bias
60.1 See Section 151 for Precision and Bias statements.
FIG. 4 Tear Resistance Test Specimens
D3574 − 17
TEST G—AIR FLOW TEST
61. Scope
61.1 The air flow test measures the ease with which air passes through a cellular structure. Air flow values can be used as an
indirect measurement of certain cell structure characteristics. The test consists of placing a flexible foam core specimen in a cavity
over a chamber and creating a specified constant air pressure differential. The rate of flow of air required to maintain this pressure
differential is the air flow value. This test is normally for slab foam products or for the core materials of molded products.
Alternative methods can be used to measure air flow through molded skins or extremely high air flow products (see Note 21).
NOTE 20—This standard is identical to ISO 7231.
NOTE 21—For measuring air flow of products, such as very tight viscoelastic foams or very high air flow foams, which can have air flows beyond the
range of this method, very good success has been achieved by using the equipment specified in Test Method D737. Direct correlations between Test
Method D737 and this method have been established, although some modification of the D737 equipment could be necessary. Test Method D3574 air
flow times 36 will give an approximate value for Test Method D737 air flow.
62. Terminology
62.1 Definitions of Terms Specific to This Standard:
62.1.1 air flow value—the volume of air per second at standard temperature and atmospheric pressure required to maintain a
constant pressure differential of 125 Pa across a flexible foam specimen approximately 50 by 50 by 25 mm.
62.1.2 air flow parallel to foam rise—the air flow value obtained when the air enters and leaves the mounted specimen parallel
to foam rise.
63. Apparatus
63.1 A schematic drawing of the apparatus, including the specimen mounting chamber, manometer, air flow meters, blow
meters, blower, and voltage control, is shown in Fig. 5.
Gummaraju, R.V., Pask, R.F., Koller, H.J., Wujcik, S.E., and Reimann, K.A., “Evaluation, Modification and Adaptation of an Airflow Test Method for Polyurethane
Foams,” Journal of Cellular Plastics , May/June 2001.
FIG. 5 Air Flow Apparatus Schematic Diagram
D3574 − 17
63.2 Chamber, consisting of a pot approximately 130 mm in diameter and 150 mm high, with provision for mounting the foam
specimen and fittings for the manometer and air exhaust. The specimen mount cavity shall be 50.0 6 0.5 by 50.0 6 0.5 by 25.0
6 0.5 mm in size. Four foam support vanes approximately 1 mm thick and 12.5 mm high shall be placed under the opening to
prevent the foam from being pulled into the vacuum chamber. The vanes shall be spaced 12.5 mm on center from each other and
also centered relative to the bottom of the cavity opening. The manometer fitting shall enter a 1-mm hole midway along the side
of the chamber. A 25-mm pipe fitting shall be used as the exhaust outlet from the center of the bottom of the chamber.
63.3 Manometer, calibrated from 0 to 250 Pa and having an accuracy of 62 %, is required. An inclined oil manometer with
graduations of 2 Pa is recommended. A level mounted on the manometer shall be used to ensure that the proper degree of
inclination from the horizontal is maintained. Traps shall be provided to prevent indicating fluid from being accidentally drawn
into the chamber. Appendix X5 describes a suggested method for the verification of the inclined oil manometer. The manometer
can alternatively be replaced with a 0-250 Pa magnehelic gauge with graduations of 5 Pa.
63.4 Flow Meters and Blower—Low-pressure-drop air flow meters accurate to 62 % shall be used for air-flow measurements.
A given flow meter shall not be used for values less than 10 % of full scale. Air flow meters with at least 250-mm scales are
recommended. Since the flow meter calibration is temperature-and pressure-dependent, the use of the apparatus under ambient
conditions can result in erroneous readings. In cases of dispute, the apparatus shall be used under standard conditions of 23°C and
100 kPa (1 atm pressure), or else a suitable calibration correction applied. Flow meters that range from 0 to 0.01 m /s will cover
a wide range of foam cell structures, but a lesser range can be used. Actual flow is adjusted by a combination of valve restriction
and blower speed. The two-way valves shall be mounted on the output side of the flow meter to maintain the pressure drop across
the flow meter constant at any given flow level. A vacuum cleaner type unit shall be used for an exhaust blower.
63.5 Leak Test—To check the apparatus for leaks, the specimen mount cavity shall be sealed with masking tape. With all valves
closed, turn on the exhaust blower to approximately ⁄3 power and observe any movement of the manometer. The manometer
reading, if any, shall not exceed 1 Pa after a 30-s waiting period. Next, open the valve very slightly for the lowest range flow meter
reading. The flow shall be essentially zero, as evidenced by a less than 3-mm movement of the air flow meter float from its static
position. For the equipment to perform satisfactorily over its entire range, the requirements for both parts of the leak test must be
met.
64. Test Specimens
64.1 The test specimens shall be parallelepiped cut to fit the mount cavity of the apparatus. A cavity 50 by 50 mm requires a
specimen 51.0 6 0.3 by 51.0 6 0.3 by 25.0 6 0.5 mm in size. A band saw with a movable table and a double-bevel knife-edge
blade is recommended for cutting the specimens.
64.2 Three specimens per sample shall be cut parallel to the foam rise. See 62.1.2. The values reported shall be the mean of
those observed for each location and orientation.
65. Procedure
65.1 Measure each specimen in accordance with the procedure described in Section 8 to verify the specimen size.
65.2 Insert the specimen into the test cavity. Make sure that a good air seal is obtained along all edges. The top of the specimen
shall be flush with the top of the test chamber.
65.3 With all valves closed, adjust the voltage control of the apparatus to 30 %.
65.4 Open one flow-control valve slowly until a pressure differential of 100 to 150 Pa is obtained. Adjust the voltage control
carefully to obtain a pressure differential of 125 6 1 Pa.
65.5 After this pressure differential has been maintained for at least 10 s, read the scale of the flow meter.
65.6 If this reading is off-scale or less than 10 % of full scale, close that flow-control valve and open a more appropriate one.
Repeat this process until the proper manometer reading and air flow is achieved.
65.7 The air flow value shall be obtained from the flow meter scale directly, estimated from a calibration chart, or calculated
with a factor depending on the calibration system.
66. Report
66.1 Report the following information:
66.1.1 Mean air flow value in cubic metres per minute for each location and orientation.
66.1.2 Dimensions of the specimens.
66.1.3 Dimension of the mount cavity of the apparatus.
67. Prec
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