1、Designation: D7571 18Standard 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
2、 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 p
3、articularly 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
4、 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 exposure
5、s 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 hi
6、gh 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
7、 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 flam
8、e.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 repeat
9、edshort 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 det
10、ailedmanufacturing 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 pe
11、rformance 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, pro
12、ducts, 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 pe
13、rsonnel 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 Aug. 1, 2018. Published August 2018. Originallyapproved in 2
14、010. Last previous edition approved in 2014 as D7151-10(2014)1.DOI: 10.1520/D7571-18.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
15、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, ass
16、ociated 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 r
17、ecognized 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 ASTM Standards:2D123 Terminology
18、Relating to TextilesD1683 Test Method for Failure in Sewn Seams of WovenFabricsD1776 Practice for Conditioning and Testing TextilesD4391 Terminology Relating to The Burning Behavior ofTextilesD6193 Practice for Stitches and SeamsD7016 Test Method to Evaluate Edge Binding ComponentsUsed in Mattresses
19、 After Exposure to An Open Flame2.2 AATCC Test Methods:3TM 135 Dimensional Changes of Fabrics after Home Laun-dering2.3 ISO Documents:4ISO 17493 Clothing and Equipment for Protection AgainstHeat Test Method for Convective Heat Resistance Using aHot Air Circulating Oven3. Terminology3.1 The following
20、 terms are relevant to this standard:critical sewn seams, retained sewn seam strength (RSS50),seam engineering, sewn seam strength.3.2 For all terms related to flammability of textiles seeTerminology D4391.3.3 For all terminology related to textiles, see TerminologyD123.4. Significance and Use4.1 It
21、 is possible that the user of FR protective clothing willexperience repeated exposures to hot air as part of the workenvironment. While these individual exposures are not likely topose a catastrophic threat, the cumulative effect of theseexposures are likely to reduce the level of retained sewn seam
22、strength performance to a value that is measurably lower thanthe sewn seam strength performance requirement establishedfor a new item.4.2 The assembly of textile structures requires that the seamengineering used to manufacture the product anticipate how toretain the maximum sewn seam strength during
23、 the anticipatedlife cycle of the product.4.2.1 Initial sewn seam strength performance requirementsof 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 tomeasure seam failure of FR protective clot
24、hing after repeatedshort duration exposures to high heat. RSS50can also be usedto measure seam failure of FR protective clothing whenexposed to open flame after repeated short duration exposuresto high heat.4.3 These data about retained sewn seam strength are usefulto establish criteria to determine
25、 when to repair, retire, orreplace FR protective clothing.5. Materials and Manufacture5.1 Sewn seam assembly samples for testing shall be madeusing seams and stitches described in Practice D6193 andconstructed with inherently flame resistant sewing thread.5.2 Purchaser and supplier shall agree on th
26、e number ofspecimens to be tested. As a minimum, five specimens of eachconstruction shall be tested.5.3 For details about samples and conditioning see Section6.6. Sampling and Wash Conditioning6.1 Prepare samples as described in Test Method D1683,Section 8, with the following modifications:6.1.1 Cut
27、 twelve pieces of fabric sections so that each fabricsection is 600 6 2 mm (24.0 6 0.1 in.) long by 125 6 2mm(5 6 0.1 in.) wide.6.1.1.1 Separate cut fabric sections into six sets of twopieces for sample sewing.6.1.1.2 Stitch the two pieces of fabric together with theseam assembly normally used to at
28、tain critical sewn seamstrength for an FR fabric having a specific mass, as identifiedin Section 10, in lengthwise direction. This will produce sixseam samples. Each sample will measure 600 6 2 mm (24.0 60.1 in.) long by approximately 200 6 2mm(86 0.1 in.) widewhen opened. When measured from edge of
29、 fabric, the stitchline is approximately 100 6 2mm(46 0.1 in.) from eitheredge.6.2 Cut sewn seam samples into specimens for testing.6.2.1 When opened, each sewn seam specimen will measureapproximately 200 6 2mm(86 0.1 in.) long by 100 6 2mm(4 6 0.1 in.) wide with the stitching at midpoint; approxi-m
30、ately 100 mm from either the top or bottom edge.6.2.2 A total of 36 specimens will be made for testing. Aminimum of 30 specimens will be needed to complete perfor-mance evaluations.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
31、g. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Association of Textile Chemists and Colorists(AATCC), P.O. Box 12215, Research Triangle Park, NC 27709, http:/www.aatcc.org.4Available from International O
32、rganization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.chD7571 1826.3 Specimens that are to be conditioned by washing shallbe washed and dried five times using AATCC TM 135, TableI, Machine Cycle (1); Wash Temp (V); Dry Procedu
33、re (Ai)7. Baseline Sewn Seam Strength7.1 Five unwashed specimens shall be tested for sewn seamstrength in accordance with Test Method D1683 to determinebaseline sewn seam strength.7.2 Five washed specimens shall be tested for sewn seamstrength in accordance with Test Method D1683 to determinebaselin
34、e sewn seam strength.8. Retained Seam Strength After Hot Air Exposure8.1 Unwashed SpecimensFive unwashed specimens shallbe subjected to 15 consecutive exposures in a hot air circulat-ing oven as described in ISO 17493 having a temperature of260 6 1C (500 6 2F) for an interval of 2 min +10/0s.8.1.1 A
35、fter each exposure to hot air, every unwashedspecimen shall be removed from the oven and placed in a roomhaving standard conditions as directed in Practice D1776 for 206 2 min.8.1.2 After completion of the 15 consecutive hot airexposures, the unwashed specimens shall be tested for retainedsewn seam
36、strength in accordance with Test Method D1683.8.2 Washed SpecimensFive washed specimens shall besubjected to 15 consecutive exposures in a hot air circulatingoven as described in ISO 17493 and having a temperature of260 6 1C (500 6 2F) for an interval of 2 min +10/0s.8.2.1 After each exposure to hot
37、 air, every washed specimenshall be removed from oven and placed in a room havingstandard conditions as directed in Practice D1776 for 20 6 2min.8.2.2 After consecutive hot air exposures, the washed speci-mens shall be tested for retained sewn seam strength inaccordance with Test Method D1683.9. Ret
38、ained Sewn Seam Strength After Hot Air andFlame Impingement9.1 Unwashed SpecimensFive unwashed specimenswhich have been subjected to 15 consecutive exposures in a hotair circulating oven as detailed in Section 8 shall be exposed toopen flame testing using Test Method D7016, Section 8, witha modifica
39、tion of flame exposure time.9.1.1 The sewn seam shall be positioned so that the burnerface is positioned 25 mm from the edge of the sewn seam.9.1.2 Each unwashed specimen shall be subjected to threeconsecutive open flame exposures. Each exposure will be foran interval of 15 6 1 s. After each exposur
40、e to open flame,every unwashed specimen shall be removed from the burnchamber and placed in a room having standard conditions asdirected in Practice D1776 for 20 6 2 min.9.1.3 After three exposures to open flame, the unwashedspecimens shall be tested for retained sewn seam strength inaccordance with
41、 Test Method D1683.9.2 Washed SpecimensFive washed specimens whichhave been subjected to 15 consecutive exposures in a hot aircirculating oven as detailed in Section 8, shall be exposed toopen flame testing using Test Method D7016, Section 8 with amodification of flame exposure time.9.2.1 The sewn s
42、eam shall be positioned so that the burnerface is positioned 25 mm from the edge of the sewn seam.9.2.2 Each washed specimen shall be subjected to threeconsecutive open flame exposures. Each exposure will be foran interval of 15 6 1 s. After each exposure to open flame,every washed specimen shall be
43、 removed from the burnchamber and placed in a room having standard conditions asdirected in Practice D1776 for 20 6 2 min.9.2.3 After three exposures to open flame, the washedspecimens shall be tested for retained sewn seam strength inaccordance with Test Method D1683.10. Retained Sewn Seam Strength
44、 Requirement10.1 Retained sewn seam strength of unwashed and washedspecimens shall meet the following minimum values whentested in accordance with Test Method D1683:Fabric Mass,g/m2(oz/yd2)Retained Seam StrengthAfter Hot Air Exposure,N (lbf)Retained Seam StrengthAfter Hot Air Exposureand Flame Impin
45、gement,N (lbf)125185 (3.55.5) 155 (35) 88 (20)200240 (6.07.0)225 (50) 132 (30)250 and higher(7.5and higher)400 (90) 200 (50)ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are exp
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