ASTM D6476-00

Standard Test Method for Determining Dynamic Air Permeability of Inflatable Restraint Fabrics

General Information

• Status: Historical
• Publication Date: 31-Dec-1999
• ICS: 43.040.60 - Bodies and body components
• ICS: 59.080.30 - Textile fabrics
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.20 - Inflatable Restraints

Standards Content (Sample)

Designation: D 6476 – 00
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope restraints, the dynamic air permeability measured at a single
specified pressure differential.
1.1 This test method covers the procedures used to deter-
3.1.3 cushion, n—for inflatable restraints, the inflatable
mine under dynamic airflow conditions the high pressure
fabric envelope portion of a module.
permeability of permeable fabrics typically used for inflatable
3.1.4 exponent of dynamic air permeability (EXP), n—for
restraints. For the determination of air permeability of inflat-
inflatable restraints, a descriptive factor used in a mathematical
able restraint fabrics under low pressure conditions at steady-
model integral to the apparatus software which relates the
state air flow, refer to Test Method D 737.
change in dynamic air permeability as the pressure differential
1.2 Procedures and apparatus other than those stated in this
changes.
test method may be used by agreement of purchaser and
3.1.5 inflatable restraint, n—a vehicular safety device de-
supplier with the specific deviations from the standard ac-
signed to cushion an occupant or equipment during collision;
knowledged in the report.
airbag.
1.3 The values stated in either SI units or inch-pound units
3.1.6 inflator, n—for inflatable restraints, a device for
are to be regarded separately as standard. The values stated in
generating and directing expansion gases used to inflate the
each system are not exact equivalents; therefore, each system
cushion.
must be used independently of the other.
3.1.7 module, n—for inflatable restraints, an assembly typi-
1.4 This standard does not purport to address all of the
cally composed of an inflator, a cushion, a mounting device, a
safety concerns, if any, associated with its use. It is the
trigger, and a cover.
responsibility of the user of this standard to establish appro-
3.1.8 standard atmosphere for testing textiles, n—an atmo-
priate safety and health practices and determine the applica-
sphere for testing in which the air is maintained at a relative
bility of regulatory limitations prior to use.
humidity of 65 6 2 % and at a temperature of 21 6 1°C (70 6
2. Referenced Documents
2°F).
3.1.9 For definitions of other textile and statistical terms
2.1 ASTM Standards:
2
used in this test method, refer to Terminology D 123 and
D 123 Terminology Relating to Textiles
D 2906.
D 737 Test Method for Air Permeability of Textile Prod-
2
ucts
4. Summary of Test Method
2
D 1776 Practice for Conditioning Textiles for Testing
4.1 A volume of dessicated compressed air at known vol-
D 2904 Practice for Interlaboratory Testing of a Textile Test
2
ume and pressure passes through a fabric specimen into the
Method that Produces Normally Distributed Data
standard atmosphere for testing textiles. During the portion of
E 691 Practice for Conducting an Interlaboratory Study to
3
the test cycle which simulates airbag inflation, the pressure
Determine the Precision of a Test Method
differential pressure across the specimen rises to a value
3. Terminology
corresponding to a peak inflation pressure. During the portion
of the test cycle which simulates airbag deflation, the pressure
3.1 Definitions:
differential drops to 0 kPa as the air passes through the
3.1.1 average dynamic air permeability (ADAP), n—for
specimen. The time to reach the maximum pressure and the
inflatable restraints, the average of all of DAP measurements
subsequent time to correspond to similar times in an airbag
within a specified range of pressure differentials.
deployment.
3.1.2 dynamic air permeability (DAP), n—for inflatable
4.2 Software algorithms integral to the apparatus smooth
out the pressure data and determine the values for ADAP and
1
This test method is under the jurisdiction of ASTM Committee D-13 on Textile
EXP.
and is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints.
Current edition approved March 10, 2000. Published July 2000. Originally
5. Significance and Use
published as D 6476–99. Last previous edition D 6476–99.
2
Annual Book of ASTM Standards, Vol 07.01.
5.1 For matters relating to lot acceptance of commercial
3
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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D 6476
shipments and conformity to specification or other standard, 6.3 Air Compressor and Air Desiccating Cartridge, capable
refer to Section 13 of this test method. of charging the pressure vessel in the test head to the specified
5.2 This test method is u
...