1、Designation: D7571 10 (Reapproved 2014)1Standard 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
2、 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.1NOTEThe order of the wording in 4.1 was changed from “.exposures are likely not to” to “.exposures are not
3、likely to” editorially in August 2014.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 a
4、ny 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 expos
5、ures 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, so
6、me 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. T
7、his 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 he
8、at 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 retire
9、ment/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 im
10、pingement.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 require
11、ments 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 indi
12、cated 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 hazar
13、d or fire riskassessment of the materials, products, or assemblies underactual fire conditions.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, 2014. Published Augus
14、t 2014. Originallyapproved in 2010. Last previous edition approved in 2010 as D7151-10. DOI:10.1520/D7571-10R14E01.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.6 Fire testing is inherently hazardous. Adequate safe-guards for pers
15、onnel and property shall be employed inconducting these tests.1.7 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 and health practices, and determine the applic
16、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1683 Test Method for Failure in Sewn Seams of WovenApparel FabricsD1776 Practice for Conditioning and Testing TextilesD4391 Terminology Relating to The Burning Behavior of
17、TextilesD6193 Practice for Stitches and SeamsD7016 Test Method to Evaluate Edge Binding ComponentsUsed in Mattresses 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 A
18、gainstHeat Test Method for Convective Heat Resistance Using aHot Air Circulating Oven3. Terminology3.1 The following 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
19、 seeTerminology D4391.3.3 For all terminology related to textiles, see TerminologyD123.4. Significance and Use4.1 It 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
20、 a catastrophic threat, the cumulative effect of theseexposures are likely to reduce the level of retained sewn seamstrength 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 th
21、at the seamengineering used to manufacture the product anticipate how toretain the maximum sewn seam strength during 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 env
22、ironment) product.4.2.2 Retained sewn seam strength (RSS50) can be used tomeasure seam failure of FR protective clothing 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
23、 exposuresto high heat.4.3 These data about retained sewn seam strength are usefulto establish criteria to determine 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 Prac
24、tice D6193 andconstructed with inherently flame resistant sewing thread.5.2 Purchaser and supplier shall agree on the 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 Con
25、ditioning6.1 Prepare samples as described in Test Method D1683,Section 8, with the following modifications:6.1.1 Cut 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 tw
26、opieces for sample sewing.6.1.1.2 Stitch the two pieces of fabric together with theseam assembly normally used to attain 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 measur
27、e 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 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 meas
28、ureapproximately 200 6 2mm(86 0.1 in.) long by 100 6 2mm(4 6 0.1 in.) wide with the stitching at midpoint; approxi-mately 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.6.3
29、 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 Procedure (Ai)2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
30、ok 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 Organization for
31、Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.chD7571 10 (2014)127. Baseline Sewn Seam Strength7.1 Five unwashed specimens shall be tested for sewn seamstrength in accordance with Test Method D1683 to determinebaseline sewn seam stren
32、gth.7.2 Five washed specimens shall be tested for sewn seamstrength in accordance with Test Method D1683 to determinebaseline 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 ci
33、rculat-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 After 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.
34、8.1.2 After completion of the 15 consecutive hot airexposures, the unwashed specimens shall be tested for retainedsewn seam 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
35、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 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
36、 exposures, the washed speci-mens shall be tested for retained sewn seam strength inaccordance with Test Method D1683.9. Retained Sewn Seam Strength After Hot Air andFlame Impingement9.1 Unwashed SpecimensFive unwashed specimenswhich have been subjected to 15 consecutive exposures in a hotair circul
37、ating oven as detailed in Section 8 shall be exposed toopen flame testing using Test Method D7016, Section 8, witha modification 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
38、 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 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
39、After three exposures to open flame, the unwashedspecimens shall be tested for retained sewn seam strength inaccordance with 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 b
40、e exposed toopen flame testing using Test Method D7016, Section 8 with amodification of flame exposure time.9.2.1 The sewn seam 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 e
41、xposures. Each exposure will be foran interval of 15 6 1 s. After each exposure to open flame,every washed specimen shall be removed from the burnchamber and placed in a room having standard conditions asdirected in Practice D1776 for 20 6 2 min.9.2.3 After three exposures to open flame, the washeds
42、pecimens shall be tested for retained sewn seam strength inaccordance with Test Method D1683.10. Retained Sewn Seam Strength 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
43、,g/m2(oz/yd2)Retained Seam StrengthAfter Hot Air Exposure,N (lbf)Retained Seam StrengthAfter Hot Air Exposureand Flame Impingement,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
44、validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is
45、subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Head
46、quarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This sta
47、ndard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 10 (2014)13
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