ASTM_D_7025_-_09_2015e1.pdf

Designation:D702509(Reapproved 2015)1Standard Test Method forAssessing Clean Flax Fiber Fineness1This standard is issued under the fixed designation D7025;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.1NOTEThe terminology section was updated in accordance with D13 policy in February 2015.1.Scope1.1 This test method provides two options that cover thedetermination of the fineness of clean loose flax fibers by:Option 1,measuring the specific surface area by the resistanceof a plug of flax fibers to air flow under prescribed conditions,or Option 2,estimating the mass per unit length.NOTE1For other methods for determining the fineness of fibers referto Appendix X1.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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 applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1441 Practice for Sampling Cotton Fibers for TestingD1577 Test Methods for Linear Density of Textile FibersD1776 Practice for Conditioning and Testing TextilesD6798 Terminology Relating to Flax and Linen3.Terminology3.1 For terminology relating to Flax,see TerminologyD6798.3.1.1 The following terms are relevant to this standard:fineness index and specific surface index.3.2 For definitions of all other textile terms,see Terminol-ogy D123.4.Summary of Test Method4.1 Using Option 1,a predetermined mass of clean looseflax fibers generated by using a mechanical blender is placed inthe specimen holder and compressed to a fixed volume.4.1.1 The resistance to airflow is measured using a cottonfiber instrument that provides a reading.This reading isconverted to a specific surface index which is derived from thelinear density of flax.4.2 Using Option 2,the average linear density of singlefibers in a bundle is calculated from mass and length measure-ments on the bundle and the number of single fibers in thebundle.NOTE2There may be no overall correlation between the resultsobtained with Options 1 and 2.Consequently,these two options cannot beused interchangeably.In case of controversy,Option 1 shall prevail.5.Significance and Use5.1 This test method for determining fineness of cleanedflax fibers is considered satisfactory for acceptance testing ofcommercial shipments when the levels are controlled by use ofa range of calibration standards.5.1.1 If there are differences of practical significance be-tween reported test results for two or more laboratories,comparative tests should be performed by those laboratories todetermine if there is a statistical bias between them,usingcompetent statistical assistance.As a minimum,use testsamples that are as homogenous as possible,are drawn fromthe material from which the disparate test results wereobtained,and are randomly assigned in equal numbers to eachlaboratory for testing.These test results from the two labora-tories should be compared using a statistical test for unpaireddata,at a probability level chosen prior to the testing series.Ifa bias is found,either its cause must be found and corrected,orfuture test results for that material must be adjusted inconsideration of the known bias.5.2 The resistance that a plug of flax fibers offers to the flowof air is measured as an approximate indication of the averagerelative fineness of the fibers.5.2.1 The total surface area of finer fibers has a larger perunit mass and increased resistance to airflow than do coarserfibers.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.17 on Flax and Linen.Current edition approved Feb.1,2015.Published April 2015.Originallyapproved in 2004.Last previous edition approved in 2004 as D702509.DOI:10.1520/D7025-09R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.3 Instruments are available to indicate the resistance to airflow using either compressed air or a vacuum;and areconstructed(1)to measure airflow under constant pressuredrop across the plug,(2)to measure pressure drop when aconstant flow of air is maintained,or(3)to indicate resistanceto air flow from both a balanced and unbalanced Wheatstonebridge.5.4 The reliability of the results of any test meth