1、Designation: D 2258 99 (Reapproved 2005)Standard Practice forSampling Yarn for Testing1This standard is issued under the fixed designation D 2258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice describes a procedure for the division ofshipm
3、ents of yarn into test lots and the sampling of such lotsfor testing.1.2 This practice is applicable to single, plied, or cabledyarns, and cords, made of any fiber or mixture of fibers, andsupported on any form of package, including beams.1.3 This practice also describes procedures for the samplingo
4、f yarn(s) removed from woven or knitted fabrics, however,when thus sampled, the yarns are usually not representative ofentire shipments, as referred to in 1.1. Consequently, theresultant sampling can only be used to determine the charac-teristics of the yarn and is usually not used for acceptancetes
5、ting. Moreover, it should be recognized that the character-istics of yarns from fabrics may be different than the charac-teristics of the same yarn(s), prior to being entered into thefabric manufacturing process.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separatel
6、y as the standard. Within the text,the inch-pound units are shown in parentheses. The valuesstated in each system are not exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith this practice.1.5 This st
7、andard 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1
8、 ASTM Standards:2D 123 Terminology Relating to TextilesD 1578 Test Method for Breaking Strength of SkeinsD 1907 Test Method for Yarn Number by the Skein MethodD 4271 Practice for Writing Statements on Sampling in TestMethods for Textiles3. Terminology3.1 Definitions:3.1.1 beam, nin textiles, a large
9、 spool containing manyends of yarns wound parallel, and used for such purposes asweaving or warp knitting.3.1.2 beam set, nin textiles, one or more beams of yarn ina single shipment to be further processed together for a specificend use.3.1.3 bulk sample, n in the sampling of bulk material, oneor mo
10、re portions which (1) are taken from material that doesnot consist of separately identifiable units and (2) can beidentified after sampling as separate or composited units.3.1.4 case, nin textiles, a shipping unit, usually a carton,box, bale, or other container holding a number of yarnpackages.3.1.5
11、 cone, nin textiles, (1) a yarn holder or bobbin ofconical shape used as a core for a yarn package of conicalform, also called a cone core. (2) the yarn package obtainedwhen yarn is wound upon a cone core.3.1.6 end, nan individual sliver, roving, yarn, or cord.3.1.6.1 DiscussionFor yarns, one of the
12、 one or morecontinuous, multiple parallel lengths of yarn which may bewound on a yarn package or beam. For example, two lengthsof yarn wrapped parallel on a single bobbin constitute two yarnends, likewise, one thousand lengths of yarn wrapped parallelon a single beam constitutes one thousand yarn en
13、ds.3.1.7 fabric package, na length of fabric in a formsuitable for handling, storing, or shipping.3.1.7.1 DiscussionFabric packages may be unsupported,such as when folded in cases, or supported, such as on tubes,bolts, or creels. Fabric packages are frequently referred to asrolls or pieces.3.1.8 lab
14、oratory sample, na portion of material taken torepresent the lot sample, or the original material, and used inthe laboratory as a source of test specimens.1This practice is under the jurisdiction ofASTM Committee D13 on Textiles andis the direct responsibility of Subcommittee D13.58 on Yarns and Fib
15、ers.Current edition approved April 1, 2005. Published July 2005. Originallyapproved in 1964. Last previous edition approved in 1999 as D 2258 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
16、volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.9 lot, nin acceptance sampling, that part of a consign-ment or shipment consisting of material fr
17、om one productionlot.3.1.10 lot sample, none or more shipping units taken atrandom to represent an acceptance sampling lot and used as asource of laboratory samples. (Syn. bulk sample)3.1.11 primary sampling unit, nthe sampling unit contain-ing all the sources of variability which should be consider
18、ed inacceptance testing; the sampling unit taken in the first stage ofselection in any procedure for sampling a lot or shipment.3.1.12 production lot, nthat part of one manufacturersproduction made from the same nominal raw material underessentially the same conditions and designed to meet the sames
19、pecifications.3.1.13 sample, n(1) a portion of a lot of material which istaken for testing or for record purposes. (See also lot sample,laboratory sample, and specimen); ( 2) a group of specimensused, or observations made, which provides information thatcan be used for making statistical inferences
20、about the popu-lation(s) from which they were drawn.3.1.14 sampling unit, nan identifiable, discrete unit orsubunit of material that could be taken as part of a sample.3.1.14.1 DiscussionSince there are two or more stages inmost sampling schemes, the sampling units in each stage mustbe clearly ident
21、ified to avoid confusion. The number of stagesin sampling schemes is not limited, but may be as few or asmany as required by the nature of the material being sampled.There are frequently three stages of sampling: (1) takingprimary sampling units from a lot of material as a lot sample,( 2) taking lab
22、oratory samples from each of the primarysampling units in the lot sample, and (3) taking test specimensfrom each of the units in the laboratory sample.3.1.15 sample skein, nskein reeled from the package orbeam of the laboratory sample, and used in the laboratory as asource of specimens.3.1.16 specim
23、en, na specific portion of a material orlaboratory sample upon which a test is performed or which isselected for that purpose. (Syn. test specimen.)3.1.17 yarn package, na length or parallel lengths of yarnin a form suitable for handling, storing, or shipping.3.1.17.1 DiscussionPackages may be unsup
24、ported, suchas skeins or cakes, or supported having various windingpatterns, such as bobbins, cops, cones, pirns, spools, or tubes.In yarns, the word package designates the smallest unit that canbe separated from the shipment without cutting or unwindingthe yarn, not a small group of packages. Even
25、a small boxcontaining a dozen spools is treated, for sampling purposes, asa case.3.1.18 For terminology of other terms used in this practice,refer to Terminology D 123.4. Summary of Practice4.1 Instructions are given for dividing the yarn into lots, fordetermining the number of cases, beams, or fabr
26、ic packages tobe selected from each lot as a lot sample, and for determiningthe number of packages, including the number of ends,representing those packages taken from the lot sample as alaboratory sample. See Practice D 4271.5. Significance and Use5.1 Assigning a value to any property of the materi
27、al in acontainer or in a lot, consignment, or delivery involves ameasurement process that includes both sampling and testingprocedures. The correctness of the value assigned dependsupon the variability due to testing. Even when the variabilitydue to testing is minimized by carefully developed proced
28、ures,correct and consistent estimates of the true value of theproperty are possible only when the sampling procedure avoidssystematic bias, minimizes variations due to sampling, andprovides a laboratory sample of adequate size.5.2 Practice D 2258 may not give the most efficient sam-pling plan that m
29、ight be devised in special situations but doespresent a general procedure that gives satisfactory precisionwith an economical amount of sampling and one which doesnot require elaborate statistical computation based on previousknowledge of the amount of variation between primary sam-pling units (such
30、 as cases, beams or fabric packages), betweenunits of the laboratory sample taken from the primary samplingunits of the lot sample (such as yarn packages taken from acase) and between specimens taken from units of the laboratorysample (such as lengths of yarn taken from a yarn package ora fabric swa
31、tch taken from a roll or piece). Many plans thatinclude stratified sampling can be found in textbooks.5.3 The smallest number of specimens required for a givenvariability in the average result will usually be obtained by (1)maximizing the number of shipping containers in the lotsample, (2) taking a
32、single package end per shipping containerin the laboratory sample, and (3) taking only one specimen perpackage. Unfortunately, this is rarely the most economical wayto test a product because it normally costs most to take ashipping container as part of the lot sample, costs an interme-diate amount t
33、o take a package from a shipping container aspart of a laboratory sample, and costs least to take and test aspecimen from a package or yarn.5.4 To minimize the cost of sampling a lot of material, it isnecessary to agree on the required variance for the reportedaverage for a lot of material:5.4.1 Est
34、imate the variance due to lot samples, the variancedue to laboratory samples, and the variance due to testingspecimens.5.4.2 Calculate the total variance for average test results forseveral combinations of the number of lot samples, the numberof laboratory samples per lot sample, and the number ofsp
35、ecimens per laboratory sample.5.4.3 Calculate the cost of performing each of the samplingschemes considered in 5.4.2.5.4.4 Select the sampling scheme that ( 1) has the requiredprecision and (2) is most economical to perform.6. Procedure6.1 Division into LotsInstructions on the division ofproduct int
36、o lots is best given in the appropriate specification.In the absence of such instructions, sample and test as aseparate lot any portion of a shipment or order that differs fromother portions in specifications, put-up, or physical character-istics, or that is billed or designated by the supplier as a
37、separate lot. If portions of a larger order are shipped onD 2258 99 (2005)2different dates, from plants or warehouses, or in more than onecarload or truckload, treat each such separately shipped portionas a separate lot. If the cases in a shipment do not haveconsecutive numbers, divide the shipment
38、into groups of caseshaving consecutive numbers and treat each group as a separatelot if it is separated from an adjacent group by as many as tencase numbers. Treat each beam set as a separate lot.6.2 Lot SampleAs a lot sample for acceptance testing,unless otherwise agreed upon, as when specified in
39、an appli-cable material specification, proceed as follows:NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between packages or ends within a shipping unit,and between specimens from a single p
40、ackage so as to provide a samplingplan with a meaningful producers risk, consumers risk, acceptablequality level, and limiting quality level.6.2.1 Cases or Fabric PackagesFor the lot sample, assigneach case or fabric package with consecutive numbers and takefor acceptance testing, the number of case
41、s or fabric packagesspecified in Table 1. Select the cases or fabric packages by arandom process using the assigned numbers by either placingthese numbers on small slips or chips, placing them in acontainer, mixing thoroughly and drawing out the number ornumbers by selection, or by using a random nu
42、mber table or itscomputer equivalent.6.2.1.1 When fabric packages, such as bolts or pieces, arecontained in cases, consider the case as the sampling unit.When fabric packages, such as rolls are self-contained, con-sider the individual fabric package as the sampling unit.6.2.1.2 When known, fabric pa
43、ckages, such as rolls, pieces,or bolts produced from one beam set may be treated in thesame manner as beams.6.2.2 BeamsFor the lot sample, assign each beam withconsecutive numbers and take for acceptance testing, one beamfrom the beam set. Select the beam by a random process usingthe assigned number
44、s by either placing these numbers on smallslips or chips, placing them in a container, mixing thoroughlyand drawing out the number by selection, or by using a randomnumber table or its computer equivalent.6.3 Laboratory SampleFor a laboratory sample for accep-tance testing, unless otherwise agreed u
45、pon, as when specifiedin an applicable material specification, proceed as follows:6.3.1 CasesWhen sampling cases, take a total of tenpackages from the lot sample. When there are five cases in thelot sample, select randomly two packages from each case.When there are four cases in the lot sample, sele
46、ct randomlytwo packages from each case then randomly select two of thefour cases and select randomly a third package from each of theselected cases. When there are three cases in the lot sample,select randomly three packages from each case then randomlyselect one of the three cases and select random
47、ly a fourthpackage from the selected case. When there are two cases inthe lot sample, select randomly five packages from each case.When there is one case in the lot sample, select randomly tenpackages from the case.6.3.2 Fabric PackagesWhen sampling fabric packages,discard the outside layer of the f
48、abric package, and then take afull width swatch,2m(2yd.) from each selected lot samplingunit. Treat each type of yarn in the fabric, the warp and fillingyarns in woven fabrics, and the machine direction of knittedfabrics as separate sampling units. Take a total of ten endsfrom the fabric swatches. W
49、hen there are five swatches in thelot sample, select randomly two ends from each swatch. Whenthere are four swatches in the lot sample, select randomly twoends from each swatch then randomly select two of the fourswatches and select randomly a third end from each of theselected swatches. When there are three swatches in the lotsample, select randomly three ends from each swatch thenrandomly select one of the three swatches and select randomlya fourth end from the selected swatch. When there are twoswatches in the lot sample, select randomly five ends
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