ASTM D5446-08(2019)

Standard Practice for Determining Physical Properties of Fabrics, Yarns, and Sewing Thread Used in Inflatable Restraints

SIGNIFICANCE AND USE
5.1 Every ASTM test method listed in 2.1 contains a section describing its particular significance and use. Other test methods listed in 2.1 of this practice may contain sections pertaining to their particular significance and use.  
5.2 The physical testing procedures in this practice can be used in conjunction with lot sampling procedures as a basis for acceptance testing of commercial shipments of inflatable restraint fabrics. They may be used to establish the criteria by which inflatable restraint fabrics will be tested by the supplier to determine whether a lot of material is acceptable for shipment to the purchaser.  
5.3 This practice addresses all the physical properties that describe inflatable restraint fabrics and their commonly used test methods. Unless otherwise specified by agreement of purchaser and supplier, these standard test methods shall constitute the test conditions, procedures, and equipment used to determine the physical properties of fabrics used in inflatable restraints. It is intended to be used as a guideline in establishing a written material specification. The specification or agreement of purchaser and supplier may deviate from the practices described herein when (based on experience) considerations of fabric properties, material handling equipment, or inflatable restraint system design dictate otherwise.
SCOPE
1.1 This practice is a listing of the test methods commonly employed in determining the physical properties of fabrics and yarns used in the manufacture of inflatable restraints.  
1.2 Fabrics used in the manufacture of inflatable restraints may be coated or uncoated, and may be comprised of spun yarns, continuous filament yarns, or a combination thereof.  
1.3 Fabrics used in the manufacturer of inflatable restraints may be either flat or one piece woven. For the one-piece woven, follow the sampling section of D5446 and the individual test method.  
1.4 In Section 9, this practice lists is alphabetical order the procedures associated with conducting physical testing of the following fabric or yarn properties of concern to the design and manufacture of inflatable restraints.    
Yarn  
Section  
Denier (Yarn Number)  
9.3.1    
Fiber Content  
9.3.2    
Finish (Extractable Material)  
9.3.3    
Strength and Elongation  
9.3.4    
Twist  
9.3.5    
Fabric  
Air Permeability  
9.3.6    
Abrasion Resistance  
9.3.7    
Blocking  
9.3.8    
Bow and Skew  
9.3.9    
Breaking Force & Elongation  
9.3.10  
Burst Strength  
9.3.11  
Coating Adhesion  
9.3.12  
Coating Weight  
9.3.13  
Count of Woven Fabric  
9.3.14  
Dynamic Air Permeability  
9.3.28  
Edgecomb Resistance  
9.3.29  
Flammability  
9.3.15  
Fogging (Volatility)  
9.3.16  
Length  
9.3.17  
Mass per Unit Area  
9.3.18  
Non-Fibrous Material  
9.3.19  
Odor  
9.3.20  
Packability  
9.3.30  
pH  
9.3.21  
Stiffness  
9.3.22  
Tear Strength  
9.3.23  
Thickness  
9.3.24  
Warp Size Content & Residual Sizing  
9.3.25  
Width  
9.3.26  
Sewing Thread  
9.3.27  
1.5 This practice may be used in conjunction with Practice D5427 which prescribes standard practices for the accelerated aging of inflatable restraint fabrics when comparative results of physical properties before and after accelerated aging are required.  
1.6 Procedures and apparatus other than those stated in this practice may be used by agreement of purchaser and supplier with the specific deviations from the standard practice acknowledged in the report.  
1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independent of the other.  
1.8 This standa...

General Information

• Status: Published
• Publication Date: 31-Dec-2018
• ICS: 43.040.60 - Bodies and body components
• ICS: 59.080.30 - Textile fabrics
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.20 - Inflatable Restraints

Relations

• Replaces: ASTM D5446-08(2013) - Standard Practice for Determining Physical Properties of Fabrics, Yarns, and Sewing Thread Used in Inflatable Restraints
• Effective Date: 01-Jan-2019
• Refers: ASTM D2261-13(2024) - Standard Test Method for Tearing Strength of Fabrics by the Tongue (Single Rip) Procedure (Constant-Rate-of-Extension Tensile Testing Machine)
• Effective Date: 01-Jan-2024
• Refers: ASTM D5587-15(2024) - Standard Test Method for Tearing Strength of Fabrics by Trapezoid Procedure
• Effective Date: 01-Jan-2024
• Refers: ASTM D3882-08(2020) - Standard Test Method for Bow and Skew in Woven and Knitted Fabrics
• Effective Date: 01-Jul-2020
• Refers: ASTM D6479-15(2020) - Standard Test Method for Determining the Edgecomb Resistance of Woven Fabrics Used in Inflatable Restraints
• Effective Date: 15-Feb-2020
• Refers: ASTM D1422/D1422M-13(2020) - Standard Test Method for Twist in Single Spun Yarns by the Untwist-Retwist Method
• Effective Date: 01-Feb-2020
• Refers: ASTM D1777-96(2019) - Standard Test Method for Thickness of Textile Materials
• Effective Date: 01-Jul-2019
• Refers: ASTM D5587-15(2019) - Standard Test Method for Tearing Strength of Fabrics by Trapezoid Procedure
• Effective Date: 01-Jul-2019
• Refers: ASTM D6613-08(2019) - Standard Practice for Determining the Presence of Sizing in Nylon or Polyester Fabric
• Effective Date: 01-Jan-2019
• Refers: ASTM D5427-09(2019) - Standard Practice for Accelerated Aging of Inflatable Restraint Fabrics
• Effective Date: 01-Jan-2019
• Refers: ASTM D6478-10(2019) - Standard Test Method for Determining Specific Packability of Fabrics Used in Inflatable Restraints
• Effective Date: 01-Jan-2019
• Refers: ASTM D2261-13(2017)e1 - Standard Test Method for Tearing Strength of Fabrics by the Tongue (Single Rip) Procedure (Constant-Rate-of-Extension Tensile Testing Machine)
• Effective Date: 15-Jul-2017
• Refers: ASTM D2261-13(2017) - Standard Test Method for Tearing Strength of Fabrics by the Tongue (Single Rip) Procedure (Constant-Rate-of-Extension Tensile Testing Machine)
• Effective Date: 15-Jul-2017
• Refers: ASTM D123-17 - Standard Terminology Relating to Textiles
• Effective Date: 01-Mar-2017
• Refers: ASTM D6476-12(2017) - Standard Test Method for Determining Dynamic Air Permeability of Inflatable Restraint Fabrics
• Effective Date: 01-Feb-2017

Overview

ASTM D5446-08(2019) is the internationally recognized standard practice for determining the physical properties of fabrics, yarns, and sewing threads used in inflatable restraints, such as airbags. Developed by ASTM International, this standard provides comprehensive procedures for evaluating a variety of physical characteristics essential for the safety and performance of inflatable restraint systems. It is widely applied throughout the automotive and safety industries to establish material specifications, support quality assurance, and ensure regulatory compliance for products where reliable airbag functionality is critical.

Key Topics

ASTM D5446 covers a broad range of test methods and evaluates multiple physical properties to ensure the consistent quality of fabrics, yarns, and sewing threads used in the manufacture of inflatable restraints. Important focus areas include:

• Yarn Properties:

  • Denier (yarn number)
  • Fiber content
  • Finish (extractable material)
  • Strength and elongation
  • Twist

• Fabric Properties:

  • Air permeability (static and dynamic)
  • Abrasion resistance
  • Blocking
  • Bow and skew
  • Breaking force and elongation
  • Burst strength
  • Coating adhesion and coating weight
  • Count of woven fabric
  • Edgecomb resistance
  • Flammability
  • Fogging (volatility)
  • Length and width
  • Mass per unit area
  • Non-fibrous material content
  • Odor
  • Packability
  • pH
  • Stiffness
  • Tear strength
  • Thickness
  • Warp size content & residual sizing

• Sewing Thread:

  • Evaluation of sewing thread performance and compatibility with inflatable restraint requirements

The standard also outlines important procedures for sampling, laboratory testing, specimen conditioning, calibration of equipment, and reporting of test results.

Applications

ASTM D5446 serves critical functions in the design, manufacture, and quality control processes for inflatable restraint systems, such as airbags. Key applications include:

• Acceptance Testing: Used alongside lot sampling procedures, this standard forms the basis for determining the acceptability of commercial shipments of materials for airbag production.
• Material Specification: Provides a technical guideline for establishing written specifications between suppliers and purchasers, ensuring all relevant physical properties are consistently tested and documented.
• Product Development: Supports material selection and validation during the development of new or improved inflatable restraint systems.
• Regulatory Compliance: Assists manufacturers in meeting safety, health, and environmental requirements mandated by regulatory authorities.
• Quality Assurance: Minimizes variability in laboratory results by standardizing test procedures and equipment calibration.

Related Standards

ASTM D5446 references several key standards and methods to support comprehensive evaluation of inflatable restraint materials, including:

• ASTM D123 – Terminology Relating to Textiles
• ASTM D204 – Test Methods for Sewing Threads
• ASTM D276 – Test Methods for Identification of Fibers in Textiles
• ASTM D737 – Test Method for Air Permeability of Textile Fabrics
• ASTM D3775, D3776, D3774 – Methods for Count, Mass per Unit Area, and Width of Woven Fabrics
• ASTM D5034, D3786, D2261, D1424, D5587 – Breaking Strength, Burst Strength, and Tear Tests
• ASTM D5427 – Practice for Accelerated Aging of Inflatable Restraint Fabrics
• Federal Motor Vehicle Safety Standard 302 – Flammability requirement
• SAE and AATCC Methods – Additional procedures for odor, pH, blocking, and coatings

For organizations involved in the production or sourcing of airbag textiles, adherence to ASTM D5446-08(2019) is fundamental in delivering products that meet stringent safety standards and regulatory expectations.

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: D5446 −08 (Reapproved 2019)
Standard Practice for
Determining Physical Properties of Fabrics, Yarns, and
Sewing Thread Used in Inflatable Restraints
This standard is issued under the fixed designation D5446; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
Tear Strength 9.3.23
Thickness 9.3.24
1.1 This practice is a listing of the test methods commonly
Warp Size Content & Residual Sizing 9.3.25
employed in determining the physical properties of fabrics and Width 9.3.26
Sewing Thread 9.3.27
yarns used in the manufacture of inflatable restraints.
1.5 This practice may be used in conjunction with Practice
1.2 Fabrics used in the manufacture of inflatable restraints
D5427 which prescribes standard practices for the accelerated
may be coated or uncoated, and may be comprised of spun
agingofinflatablerestraintfabricswhencomparativeresultsof
yarns, continuous filament yarns, or a combination thereof.
physical properties before and after accelerated aging are
1.3 Fabrics used in the manufacturer of inflatable restraints
required.
may be either flat or one piece woven. For the one-piece
1.6 Procedures and apparatus other than those stated in this
woven, follow the sampling section of D5446 and the indi-
practice may be used by agreement of purchaser and supplier
vidual test method.
with the specific deviations from the standard practice ac-
1.4 In Section 9, this practice lists is alphabetical order the
knowledged in the report.
procedures associated with conducting physical testing of the
1.7 The values stated in either SI units or inch-pound units
followingfabricoryarnpropertiesofconcerntothedesignand
are to be regarded separately as standard. The values stated in
manufacture of inflatable restraints.
each system are not exact equivalents; therefore, each system
Yarn Section
must be used independent of the other.
Denier (Yarn Number) 9.3.1
Fiber Content 9.3.2
1.8 This standard does not purport to address all of the
Finish (Extractable Material) 9.3.3
safety concerns, if any, associated with its use. It is the
Strength and Elongation 9.3.4
responsibility of the user of this standard to establish appro-
Twist 9.3.5
Fabric
priate safety, health, and environmental practices and deter-
Air Permeability 9.3.6
mine the applicability of regulatory limitations prior to use.SEE
Abrasion Resistance 9.3.7
Note 3.
Blocking 9.3.8
Bow and Skew 9.3.9
Breaking Force & Elongation 9.3.10
2. Referenced Documents
Burst Strength 9.3.11
Coating Adhesion 9.3.12
2.1 ASTM Standards:
Coating Weight 9.3.13
D123 Terminology Relating to Textiles
Count of Woven Fabric 9.3.14
Dynamic Air Permeability 9.3.28 D204 Test Methods for Sewing Threads
Edgecomb Resistance 9.3.29
D276 Test Methods for Identification of Fibers in Textiles
Flammability 9.3.15
D737 Test Method for Air Permeability of Textile Fabrics
Fogging (Volatility) 9.3.16
Length 9.3.17
D751 Test Methods for Coated Fabrics
Mass per Unit Area 9.3.18
D1059 Test Method for Yarn Number Based on Short-
Non-Fibrous Material 9.3.19
Length Specimens
Odor 9.3.20
Packability 9.3.30 D1388 Test Method for Stiffness of Fabrics
pH 9.3.21
D1422/D1422M TestMethodforTwistinSingleSpunYarns
Stiffness 9.3.22
by the Untwist-Retwist Method
ThispracticeisunderthejurisdictionofASTMCommitteeD13onTextilesand
is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2019. Published January 2019. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1993. Last previous edition approved in 2013 as D5446 – 08 (2013). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5446-08R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5446 − 08 (2019)
D1423 Test Method for Twist in Yarns by Direct-Counting 2.4 Ford Motor Company Standards:
D1424 Test Method for Tearing Strength of Fabrics by FLTM BO116-03 Fogging Standard
FLTM BN13-1 Coating Adhesion
Falling-Pendulum (Elmendorf-Type) Apparatus
D1777 Test Method for Thickness of Textile Materials 2.5 AATCC Methods:
D1907 Test Method for Linear Density of Yarn (Yarn Num- Method 81 pH of Water—Extract from Wet Processed Tex-
tiles
ber) by the Skein Method
D2256 Test Method for Tensile Properties of Yarns by the
3. Terminology
Single-Strand Method
D2257 Test Method for Extractable Matter in Textiles 3.1 Definitions:
D2261 Test Method for Tearing Strength of Fabrics by the 3.2 For all terminology relating to D13.20, Inflatable
restraints, refer to Terminologies D3990 and D6799.
Tongue (Single Rip) Procedure (Constant-Rate-of-
3.2.1 The following terms are relevant to this standard:
Extension Tensile Testing Machine)
coated fabric, inflatable restraint.
D3773 Test Methods for Length of Woven Fabric
D3774 Test Method for Width of Textile Fabric
3.3 For all other terms related to textiles, see Terminology
D3775 Test Method for End (Warp) and Pick (Filling) Count
D123.
of Woven Fabrics
4. Summary of Test Method
D3776 Test Methods for Mass Per Unit Area (Weight) of
Fabric
4.1 Testspecimensaretakenfromsamplerollsoffabricand
D3786 Test Method for Bursting Strength of Textile
tested using prescribed laboratory procedures, conditions and
Fabrics—Diaphragm Bursting Strength Tester Method
equipment by the supplier to determine the physical properties
D3882 Test Method for Bow and Skew in Woven and
of the fabric in accordance with the requirements of the
Knitted Fabrics
purchaser.
D3990 Terminology Relating to Fabric Defects
5. Significance and Use
D4032 Test Method for Stiffness of Fabric by the Circular
Bend Procedure
5.1 EveryASTM test method listed in 2.1 contains a section
D4157 Test Method for Abrasion Resistance of Textile
describing its particular significance and use. Other test meth-
Fabrics (Oscillatory Cylinder Method)
odslistedin2.1ofthispracticemaycontainsectionspertaining
D4851 Test Methods for Coated and Laminated Fabrics for
to their particular significance and use.
Architectural Use
5.2 The physical testing procedures in this practice can be
D5034 TestMethodforBreakingStrengthandElongationof
used in conjunction with lot sampling procedures as a basis for
Textile Fabrics (Grab Test)
acceptance testing of commercial shipments of inflatable
D5427 Practice forAcceleratedAging of Inflatable Restraint
restraint fabrics. They may be used to establish the criteria by
Fabrics
which inflatable restraint fabrics will be tested by the supplier
D5587 Test Method for Tearing Strength of Fabrics by
to determine whether a lot of material is acceptable for
Trapezoid Procedure
shipment to the purchaser.
D6476 Test Method for Determining Dynamic Air Perme-
5.3 This practice addresses all the physical properties that
ability of Inflatable Restraint Fabrics
describe inflatable restraint fabrics and their commonly used
D6478 Test Method for Determining Specific Packability of
test methods. Unless otherwise specified by agreement of
Fabrics Used in Inflatable Restraints
purchaser and supplier, these standard test methods shall
D6479 Test Method for Determining the Edgecomb Resis-
constitute the test conditions, procedures, and equipment used
tance of Woven Fabrics Used in Inflatable Restraints
todeterminethephysicalpropertiesoffabricsusedininflatable
D6613 Practice for Determining the Presence of Sizing in
restraints.Itisintendedtobeusedasaguidelineinestablishing
Nylon or Polyester Fabric
a written material specification.The specification or agreement
D6799 Terminology Relating to Inflatable Restraints
of purchaser and supplier may deviate from the practices
F778 Methods for Gas Flow Resistance Testing of Filtration
described herein when (based on experience) considerations of
Media
fabric properties, material handling equipment, or inflatable
2.2 Federal Standards: restraint system design dictate otherwise.
Motor Vehicle Safety Standard 302—Flammability
6. Apparatus
2.3 SAE Standards:
6.1 Periodic laboratory certification of test equipment used
J912-A Resistance to Blocking
in accordance with this practice is required to reduce test
J1351 Determination of Odor
variability due to precision and bias.
3 5
Available from the Superintendent of Documents, U.S. Government Printing Available from Ford Motor Company, Engineering Department, Body Engi-
Office, Washington, DC 20525. neering Building, Room 1145, 21500 Oakwood Boulevard, Dearborn, MI 48124.
4 6
Available from the Society of Automotive Engineers, 400 Commonwealth Available from American Association of Textiles Chemists and Colorists, PO
Drive, Warrendale, PA 15096-0001. Box 12215, Research Triangle Park, NC 27709.
D5446 − 08 (2019)
6.2 For inflatable restraints, all test equipment used in 7.3.4 Take no test specimen closer to the selvage of the
accordancewiththeproceduresreferencedinthispracticeshall fabric than ⁄10 the width of the fabric or 125 mm (5 in.),
be certified for calibration annually by an independent agency whichever is smaller.
or equipment manufacturer whose results are traceable to
National Institute of Science and Technology (NIST) or other
8. Conditioning
national standards laboratory. The test parameters of the
8.1 Test specimens shall be preconditioned as directed by
equipment shall be tested within the operating ranges covered
the particular test method or as agreed upon between the
in the material specification or equivalent document.
purchaser and supplier.
8.2 Prior to testing a physical property, the test specimens
7. Sampling
shall be brought to moisture equilibrium at ambient atmo-
7.1 Lot Sample:
spheric pressure, at 21 6 1°C (70 6 2°F), and at 65 % 62%
7.1.1 Forthesizeofanacceptancesamplinglotoffabricfor
relative humidity, unless directed to do otherwise by the test
inflatable restraints, use the number of fabric rolls in a
procedure or an agreement by purchaser and supplier.
shipment of a single fabric style unless otherwise agreed upon
8.3 Equilibrium is considered to have been reached when
between the purchaser and supplier. If the fabrics are one piece
the increase in mass of the specimen in successive weightings
woven, use the number of units in the shipment as the
made at intervals of not less than 2 h does not exceed 0.1 % of
acceptance sampling lot.
the mass of the specimen.
7.1.2 Unless otherwise agreed upon by purchaser and
supplier,takeasalotsamplealloftherollsoronepiecewoven
NOTE 1—Certain fibers and coatings may exhibit slow rates of
units in a shipment of fabric. Consider rolls of fabric to be the achievingmoistureequilibrium.Whenthisoccurs,apreconditioningcycle
such as described in Practice D1776 may be agreed upon between
primary sampling units.
contractual parties.
7.1.3 For the size of an acceptance lot of yarn, use the lot
determination and sample plan agreed upon by purchaser and
9. Procedures
supplier.
9.1 Secure test specimens from laboratory samples in ac-
7.2 Laboratory Sample:
cordance with the sampling section (Section 7) of this practice
7.2.1 Anentirerolloffabricorafull-widthcutfromtheend
for each test required by the material specification or agree-
of a roll within a lot sample or one piece woven units
ment of purchaser and supplier.
constitutes a laboratory sample depending on which physical
9.2 Precondition and condition the test specimens in accor-
property is to be tested.
dance with the conditioning section (Section 8) of this practice
7.2.1.1 For fabric width, fabric bow, and fabric length, the
for each test required by the material specification or agree-
rolls in the lot sample serve as the laboratory sample.
ment of purchaser and supplier.
7.2.1.2 For all other physical properties, take as the labora-
tory sample a full width cut of fabric2m(2yd) long from the
9.3 Test the specimens in accordance with each test method
endofeachrollinthelotsampleifthereisnoevidencethatthe
specified.
fabric is distorted; if there is evidence of physical distortion on
9.3.1 Determine the denier or yarn number in accordance
the outside of the fabric roll, take a sample cut from the
with Test Method D1907 for packaged yarn or Test Method
resulting end of the roll after removing and discarding the
D1059 for beamed yarn or yarns removed from fabric test
distorted portion of fabric.
specimens.
7.2.2 An entire yarn package constitutes a laboratory
9.3.1.1 When using Test Method D1907, make one deter-
sample for yarn testing.
mination from each
...