ASTM_D_7571_-_21.pdf

Designation:D757121Standard Specification forRetained Sewn Seam Strength After Exposures to Hot Airand Open Flame1This standard is issued under the fixed designation D7571;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONSewn seam strength of flame resistant textile products is a critical measurement of structuralintegrity.This is particularly important for flame resistant(FR)personal protective clothing andequipment(PPE),which is designed to provide safety to any worker who may,during the service lifeof the PPE,experience multiple short term exposures to high heat.While“new”FR protective clothingitems can provide the wearer with protection that meets a specific performance requirement,it isuseful to know what the cumulative effects of repeated exposures to high heat can do to the integrityof the sewn seams used to construct protective clothing items.In addition,it is useful to know howthe cumulative exposures can affect the sewn seam strength performance of the PPE when exposed toan open flame for a short period of time.During normal use,some FR specialized clothing items can,for short durations,be repeatedlyexposed to high heat.While the cumulative effect of repeated short duration exposures to high heatis known to result in a loss of fabric strength,these same exposures can also result in a loss of sewingthread break strength.This loss of break strength can result in lower retained sewn seam strength thatcan put the wearer at potential risk of injury if the garment is too weak to maintain integrity of thestructure.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 seamstrength 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 establishselection,care,maintenance and retirement/replacement of FR protective clothing.1.Scope1.1 This specification covers the retained sewn seamstrength of flame resistant fabric subassemblies after repeatedshort duration exposures to hot air or repeated short-durationexposures to hot air and subsequent short-term exposures toopen-flame impingement.1.1.1 This specification is used to determine minimumretained sewn seam strength after these exposures.1.2 This standard is not intended to serve as a detailedmanufacturing or purchasing specification,but can be refer-enced in purchase contracts to ensure that minimum perfor-mance requirements are met.1.3 Controlled laboratory tests used to determine compli-ance with the performance requirements of this standard shallnot be deemed as establishing performance levels for allsituations to which wearers of FR protective clothing arepotentially exposed.1.4 Mandatory requirements are indicated by use of shall;recommendations and advising information is indicated byshould.1.5 This standard is used to measure and describe theresponse of materials,products,or assemblies to heat andflame under controlled conditions,but does not by itselfincorporate all factors required for fire hazard or fire riskassessment of the materials,products,or assemblies underactual fire conditions.1.6 Fire testing is inherently hazardous.Adequate safe-guards for personnel and property shall be employed inconducting these tests.1This specification is under the jurisdiction of ASTM Committee D13 onTextiles and is the direct responsibility of Subcommittee D13.52 on Flammability.Current edition approved July 1,2021.Published August 2021.Originallyapproved in 2010.Last previous edition approved in 2020 as D7151-20.DOI:10.1520/D7571-21.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.11.7 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 A