ASTM D6476-08
(Test Method)Standard Test Method for Determining Dynamic Air Permeability of Inflatable Restraint Fabrics
Standard Test Method for Determining Dynamic Air Permeability of Inflatable Restraint Fabrics
SIGNIFICANCE AND USE
For matters relating to lot acceptance of commercial shipments and conformity to specification or other standard, refer to Section 13 of this test method.
This test method is useful in the selection and design validation of permeable, uncoatable fabrics used in inflatable restraint cushions. The dynamic conditions and higher pressure differentials of this test method may better simulate the inflation and deflation cycle of an airbag module during deployment than do the steady-state conditions of Test Method D 737.
5.2.1 Only uncoated, permeable fabrics should be used. Use of coated fabrics may yield invalid results and potentially damage the test apparatus.
Within the limits of variance expressed in Section 12, this test method is useful for design validation and may be suitable for incorporation in a material specification or for lot acceptance testing of commercial shipments. Caution is advised on very low permeability fabrics or with the 200 cm3. size test heat because between-laboratory precision as presented in Section 12 may be as high as 21 %.
This test method may be used for materials other than inflatable restraint fabrics which experience dynamic air permeability in sudden bursts. In such cases, the physical apparatus or its software algorithms may require modification to provide suitability for use.
Due to the split-second time interval for testing, the pressure versus time data is subject to recording anomalies and electronic noise. The data should be digitally filtered to obtain the underlying smooth pressure curve prior to data analysis. The software in the apparatus includes a reliable algorithm both to smooth the curve and to determine the exponent of air permeability.
It is inherent in the design and operation of this equipment that major components key to the calibration and measurements are specific to the individual test head. The size or permeability measuring range of the test head is typically chosen to correspond to the fabric spe...
SCOPE
1.1 This test method covers the procedures used to determine under dynamic airflow conditions the high pressure permeability of permeable, uncoated fabrics typically used for inflatable restraints. For the determination of air permeability of inflatable restraint fabrics under low pressure conditions at steady-state air flow, refer to Test Method D 737.
1.2 Procedures and apparatus other than those stated in this test method may be used by agreement of purchaser and supplier with the specific deviations from the standard acknowledged in the report.
1.3 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 independently of the other.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6476 – 08
Standard Test Method for
Determining Dynamic Air Permeability of Inflatable Restraint
1
Fabrics
This standard is issued under the fixed designation D6476; 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 3.1.1 The following terms are relevant to this standard:
average dynamic air permeability (ADAP), dynamic air per-
1.1 This test method covers the procedures used to deter-
meability (DAP), cushion, exponent of dynamic air permeabil-
mine under dynamic airflow conditions the high pressure
ity (EXP, ) inflatable restrain, inflator, module, standard atmo-
permeability of permeable, uncoated fabrics typically used for
sphere for testing textiles
inflatable restraints. For the determination of air permeability
3.2 For all other terms related to textiles, see Terminology
of inflatable restraint fabrics under low pressure conditions at
D123.
steady-state air flow, refer to Test Method D737.
1.2 Procedures and apparatus other than those stated in this
4. Summary of Test Method
test method may be used by agreement of purchaser and
4.1 A volume of dessicated compressed air at known vol-
supplier with the specific deviations from the standard ac-
ume and pressure passes through a fabric specimen into the
knowledged in the report.
standard atmosphere for testing textiles. During the portion of
1.3 The values stated in either SI units or inch-pound units
the test cycle which simulates airbag inflation, the pressure
are to be regarded separately as standard. The values stated in
differential pressure across the specimen rises to a value
each system are not exact equivalents; therefore, each system
corresponding to a peak inflation pressure. During the portion
must be used independently of the other.
of the test cycle which simulates airbag deflation, the pressure
1.4 This standard does not purport to address all of the
differential drops to 0 kPa as the air passes through the
safety concerns, if any, associated with its use. It is the
specimen. The time to reach the maximum pressure and the
responsibility of the user of this standard to establish appro-
subsequent time to correspond to similar times in an airbag
priate safety and health practices and determine the applica-
deployment.
bility of regulatory limitations prior to use.
4.2 Software algorithms integral to the apparatus smooth
2. Referenced Documents out the pressure data and determine the values for ADAP and
2
EXP.
2.1 ASTM Standards:
D123 Terminology Relating to Textiles
5. Significance and Use
D737 Test Method for Air Permeability of Textile Fabrics
5.1 For matters relating to lot acceptance of commercial
D1776 Practice for Conditioning and Testing Textiles
shipments and conformity to specification or other standard,
D2904 Practice for Interlaboratory Testing of a Textile Test
refer to Section 13 of this test method.
Method that Produces Normally Distributed Data
5.2 This test method is useful in the selection and design
D6799 Terminology Relating to Inflatable Restraints
validation of permeable, uncoatable fabrics used in inflatable
E691 Practice for Conducting an Interlaboratory Study to
restraint cushions.The dynamic conditions and higher pressure
Determine the Precision of a Test Method
differentials of this test method may better simulate the
3. Terminology inflation and deflation cycle of an airbag module during
deployment than do the steady-state conditions of Test Method
3.1 For all terminology relating to D13.20, Inflatable re-
D737.
straints, refer to Terminology D6799.
5.2.1 Only uncoated, permeable fabrics should be used. Use
of coated fabrics may yield invalid results and potentially
1
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
damage the test apparatus.
and is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints.
Current edition approved July 1, 2008. Published July 2008. Originally approved 5.3 Within the limits of variance expressed in Section 12,
in 2000. Last previous edition approved in 2005 as D6476–05. DOI: 10.1520/
this test method is useful for design validation and may be
D6476-08.
suitable for incorporation in a material specification or for lot
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
acceptance testing of commercial shipments. Caution is ad-
contactASTM Customer Service at service@astm.org. ForAnnual Book ofASTM
3
Standards volume information, refer to the standard’s Document Summary page on
vised on very low permeability fabrics or with the 200 cm .
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:D6476–05 Designation: D 6476 – 08
Standard Test Method for
Determining Dynamic Air Permeability of Inflatable Restraint
1
Fabrics
This standard is issued under the fixed designation D 6476; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the procedures used to determine under dynamic airflow conditions the high pressure permeability
of permeable, uncoated fabrics typically used for inflatable restraints. For the determination of air permeability of inflatable
restraint fabrics under low pressure conditions at steady-state air flow, refer to Test Method D 737.
1.2 Procedures and apparatus other than those stated in this test method may be used by agreement of purchaser and supplier
with the specific deviations from the standard acknowledged in the report.
1.3 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 independently of the other.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D 123 Terminology Relating to Textiles
D 737 Test Method for Air Permeability of Textile Products Fabrics
D 1776Practice for Conditioning Textiles for Testing Practice for Conditioning and Testing Textiles
D 2904 Practice for Interlaboratory Testing of a Textile Test Method that Produces Normally Distributed Data D2906Practice
for State-
ments on
Precision
and Bias for
Textiles
D 6799 Terminology Relating to Inflatable Restraints
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1Definitions:
3.1.1For definitions of other textile and statistical terms used in this standard, refer to Terminology D123, D2906 and
Terminology D6799.
3.1 For all terminology relating to D13.20, Inflatable restraints, refer to Terminology D 6799.
3.1.1 The following terms are relevant to this standard: average dynamic air permeability (ADAP), dynamic air permeability
(DAP), cushion, exponent of dynamic air permeability (EXP, ) inflatable restrain, inflator, module, standard atmosphere for testing
textiles
3.2 For all other terms related to textiles, see Terminology D 123.
4. Summary of Test Method
4.1 A volume of dessicated compressed air at known volume and pressure passes through a fabric specimen into the standard
atmosphere for testing textiles. During the portion of the test cycle which simulates airbag inflation, the pressure differential
1
This test method is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints .
Current edition approved AprilJuly 1, 2005.2008. Published May 2005.July 2008. Originally approved in 2000. Last previous edition approved in 20022005 as
D 6476–025.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D6476–08
pressure across the specimen rises to a value corresponding to a peak inflation pressure. During the portion of the test cycle which
simulates airbag deflation, the pressure differential drops to 0 kPa as the air passes through the specimen. The time to reach the
maximum pressure and the subsequent time to correspond to similar times in an airbag deployment.
4.2 Software algorithms integral to the apparatus smooth out the pressure data and determine the values for ADAP and EXP.
5. Significance and Use
5.1 For matters relating to lot acceptance of commercial shipments and conformity to specification or other standard, refer to
Section 13 of this test method.
5.2 This test method is useful in the selection and design validation of permeable, uncoatable fabrics used in inflatable restraint
cushi
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.