ASTM D7571-21

Standard Specification for Retained Sewn Seam Strength After Exposures to Hot Air and Open Flame

SIGNIFICANCE AND USE
4.1 It is possible that the user of FR protective clothing will experience repeated exposures to hot air as part of the work environment. While these individual exposures are not likely to pose a catastrophic threat, the cumulative effect of these exposures are likely to reduce the level of retained sewn seam strength performance to a value that is measurably lower than the sewn seam strength performance requirement established for a new item.  
4.2 The assembly of textile structures requires that the seam engineering used to manufacture the product anticipate how to retain the maximum sewn seam strength during the anticipated life cycle of the product.  
4.2.1 Initial sewn seam strength performance requirements of FR textile products measures sewn seam strength of a new (never exposed to heat environment) product.  
4.2.2 Retained sewn seam strength (RSS50) can be used to measure seam failure of FR protective clothing after repeated short duration exposures to high heat. RSS50 can also be used to measure seam failure of FR protective clothing when exposed to open flame after repeated short duration exposures to high heat.  
4.3 These data about retained sewn seam strength are useful to establish criteria to determine when to repair, retire, or replace FR protective clothing.
SCOPE
1.1 This specification covers the retained sewn seam strength of flame resistant fabric subassemblies after repeated short duration exposures to hot air or repeated short-duration exposures to hot air and subsequent short-term exposures to open-flame impingement.  
1.1.1 This specification is used to determine minimum retained sewn seam strength after these exposures.  
1.2 This standard is not intended to serve as a detailed manufacturing or purchasing specification, but can be referenced in purchase contracts to ensure that minimum performance requirements are met.  
1.3 Controlled laboratory tests used to determine compliance with the performance requirements of this standard shall not be deemed as establishing performance levels for all situations to which wearers of FR protective clothing are potentially exposed.  
1.4 Mandatory requirements are indicated by use of shall; recommendations and advising information is indicated by should.  
1.5 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.  
1.6 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.  
1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 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.

General Information

• Status: Published
• Publication Date: 30-Jun-2021
• ICS: 59.080.30 - Textile fabrics
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.52 - Flammability

Relations

• Refers: ASTM D6193-16(2020) - Standard Practice for Stitches and Seams
• Effective Date: 01-Jul-2020

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:D7571 −21
Standard Specification for
Retained Sewn Seam Strength After Exposures to Hot Air
1
and Open Flame
This standard is issued under the fixed designation D7571; 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.
INTRODUCTION
Sewn seam strength of flame resistant textile products is a critical measurement of structural
integrity. This is particularly important for flame resistant (FR) personal protective clothing and
equipment (PPE), which is designed to provide safety to any worker who may, during the service life
ofthePPE,experiencemultipleshorttermexposurestohighheat.While“new”FRprotectiveclothing
items can provide the wearer with protection that meets a specific performance requirement, it is
useful to know what the cumulative effects of repeated exposures to high heat can do to the integrity
of the sewn seams used to construct protective clothing items. In addition, it is useful to know how
the cumulative exposures can affect the sewn seam strength performance of the PPE when exposed to
an open flame for a short period of time.
During normal use, some FR specialized clothing items can, for short durations, be repeatedly
exposed to high heat. While the cumulative effect of repeated short duration exposures to high heat
is known to result in a loss of fabric strength, these same exposures can also result in a loss of sewing
thread break strength. This loss of break strength can result in lower retained sewn seam strength that
can put the wearer at potential risk of injury if the garment is too weak to maintain integrity of the
structure.
While there are recognized minimum sewn seam strength values required for new FR garments,
never exposed to heat or flame hazard, this standard is intended to measure the retained sewn seam
strength after repeated exposures to high heat and a subsequent exposure to open flame.
These data may be useful as additional information for agencies that want criteria to establish
selection, care, maintenance and retirement/replacement of FR protective clothing.
1. Scope 1.3 Controlled laboratory tests used to determine compli-
ance with the performance requirements of this standard shall
1.1 This specification covers the retained sewn seam
not be deemed as establishing performance levels for all
strength of flame resistant fabric subassemblies after repeated
situations to which wearers of FR protective clothing are
short duration exposures to hot air or repeated short-duration
potentially exposed.
exposures to hot air and subsequent short-term exposures to
open-flame impingement. 1.4 Mandatory requirements are indicated by use of shall;
1.1.1 This specification is used to determine minimum recommendations and advising information is indicated by
retained sewn seam strength after these exposures. should.
1.2 This standard is not intended to serve as a detailed 1.5 This standard is used to measure and describe the
manufacturing or purchasing specification, but can be refer- response of materials, products, or assemblies to heat and
enced in purchase contracts to ensure that minimum perfor- flame under controlled conditions, but does not by itself
mance requirements are met. incorporate all factors required for fire hazard or fire risk
assessment of the materials, products, or assemblies under
1 actual fire conditions.
This specification is under the jurisdiction of ASTM Committee D13 on
Textiles and is the direct responsibility of Subcommittee D13.52 on Flammability.
1.6 Fire testing is inherently hazardous. Adequate safe-
Current edition approved July 1, 2021. Published August 2021. Originally
guards for personnel and property shall be employed in
approved in 2010. Last previous edition approved in 2020 as D7151- 20. DOI:
10.1520/D7571-21. conducting these tests.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7571−21
1.7 This standard does not purport to address all of the 4.2 The assembly of textile structures requires that the seam
safety concerns, if any, associated with its use. It is the engineering used to manufacture the product anticipate how to
responsibility of the user of this standard to establish appro- retain the maximum sewn seam strength during the anticipated
priate safety, health, and environmental practices and deter- life cycle of the product.
mine the applicability of reg
...

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: D7571 − 20 D7571 − 21
Standard Specification for
Retained Sewn Seam Strength After Exposures to Hot Air
1
and Open Flame
This standard is issued under the fixed designation D7571; 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.
INTRODUCTION
Sewn seam strength of flame resistant textile products is a critical measurement of structural
integrity. This is particularly important for flame resistant (FR) personal protective clothing and
equipment (PPE), which is designed to provide safety to any worker who may, during the service life
of the PPE, experience multiple short term exposures to high heat. While “new” FR protective clothing
items can provide the wearer with protection that meets a specific performance requirement, it is
useful to know what the cumulative effects of repeated exposures to high heat can do to the integrity
of the sewn seams used to construct protective clothing items. In addition, it is useful to know how
the cumulative exposures can affect the sewn seam strength performance of the PPE when exposed to
an open flame for a short period of time.
During normal use, some FR specialized clothing items can, for short durations, be repeatedly
exposed to high heat. While the cumulative effect of repeated short duration exposures to high heat
is known to result in a loss of fabric strength, these same exposures can also result in a loss of sewing
thread break strength. This loss of break strength can result in lower retained sewn seam strength that
can put the wearer at potential risk of injury if the garment is too weak to maintain integrity of the
structure.
While there are recognized minimum sewn seam strength values required for new FR garments,
never exposed to heat or flame hazard, this standard is intended to measure the retained sewn seam
strength after repeated exposures to high heat and a subsequent exposure to open flame.
These data may be useful as additional information for agencies that want criteria to establish
selection, care, maintenance and retirement/replacement of FR protective clothing.
1. Scope
1.1 This specification covers the retained sewn seam strength of flame resistant fabric subassemblies after repeated short duration
exposures to hot air or repeated short-duration exposures to hot air and subsequent short-term exposures to open-flame
impingement.
1.1.1 This specification is used to determine minimum retained sewn seam strength after these exposures.
1.2 This standard is not intended to serve as a detailed manufacturing or purchasing specification, but can be referenced in
purchase contracts to ensure that minimum performance requirements are met.
1
This specification is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.52 on Flammability.
Current edition approved July 1, 2020July 1, 2021. Published August 2018August 2021. Originally approved in 2010. Last previous edition approved in 20182020 as
D7151-18. - 20. DOI: 10.1520/D7571-20.10.1520/D7571-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7571 − 21
1.3 Controlled laboratory tests used to determine compliance with the performance requirements of this standard shall not be
deemed as establishing performance levels for all situations to which wearers of FR protective clothing are potentially exposed.
1.4 Mandatory requirements are indicated by use of shall; recommendations and advising information is indicated by should.
1.5 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under
controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials,
products, or assemblies under actual fire conditions.
1.6 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these
tests.
1.7 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, health, and environmental practices and determine the applicability of
regulatory limitations pri
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