1、Designation: D 1448 05Standard Test Method forMicronaire Reading of Cotton Fibers1This standard is issued under the fixed designation D 1448; 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 pa
2、rentheses 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 test method covers the determination of themicronaire readin
3、g of loose cotton fibers by measuring theresistance of a plug of cotton fibers to air flow under prescribedconditions.NOTE 1For other methods for determining the fineness of fibers basedon the air-flow principle, refer to Test Method D 1449, Test Method forSpecific Area and Immaturity Ratio of Cotto
4、n Fibers (ArealometerMethod),2and to Test Method D 1282, Test Method for Resistance to AirFlow as an Indication of Average Fiber Diameter of Wool Top, CardSliver, and Scoured Wool.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespo
5、nsibility 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:2D 123 Terminology Relating to TextilesD 1282 Test Method for Resistance to Airflow as an Ind
6、i-cation ofAverage Fiber Diameter of Wool Top, Card Sliverand Scoured WoolD 1441 Practice for Sampling Cotton Fibers for TestingD 1449 Test Method for SpecificArea and Immaturity Ratioof Cotton Fibers (Arealometer MethodD 1776 Practice for Conditioning and Testing TextilesD 7139 Terminology for Cott
7、on Fibers3. Terminology3.1 For all terminology related to D13.11, refer to Termi-nology D 7139.3.1.1 The following terms are relevant to this standard:calibration cotton standards, fineness, micronaire reading.,3.2 For all other terminology related to textiles, refer toTerminology D 123.4. Summary o
8、f Test Method4.1 The resistance a plug of cotton fibers offers to the flowof air is measured as an approximate indication of the finenessof fiber. A predetermined mass of loose cotton fibers is placedin the specimen holder and compressed to a fixed volume. Theresistance to air flow is measured and e
9、xpressed as micronairereading. Instruments available to measure resistance to air flowuse compressed air or vacuum and are constructed to measureair flow under constant pressure drop across the plug, tomeasure pressure drop when a constant flow of air is main-tained, or to indicate resistance to air
10、 flow from both a balancedand unbalanced wheatstone bridge.5. Significance and Use5.1 This test method for determining micronaire reading ofcotton fibers is considered satisfactory for acceptance testing ofcommercial shipments when the levels are controlled by use ofa full range of calibration cotto
11、n standards.5.1.1 In case of a dispute arising from differences inreported test results when using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plier should conduct comparative tests to determine if there isa statistical bias between their laboratories. C
12、ompetent statis-tical assistance is recommended for the investigation of bias.As a minimum, the two parties should take a group of testspecimens that are as homogeneous as possible and that arefrom a lot of material of the type in question. The testspecimens should then be randomly assigned in equal
13、 numbersto each laboratory for testing. The average results from the twolaboratories should be compared using Students t-test forunpaired data and an acceptable probability level chosen by thetwo parties before the testing is begun. If a bias is found, eitherits cause must be found and corrected or
14、the purchaser and thesupplier must agree to interpret future test results in the light ofthe known bias.5.2 The micronaire reading of cotton fibers is a function ofboth fineness and maturity and is related to mill processingperformance and to the quality of the end products. Factorscorrelated with m
15、icronaire reading include cleaning efficiency,neppiness, and the strength and uniformity of the yarn.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.Current edition approved March 1, 2005. Published
16、 April 2005. Originallyapproved in 1954 to replace portions of D 414. Last previous edition approved in1997 as D 144897.2For 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
17、 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.NOTE 2A modification of this test method is used in commercialtrading to select bales which will conform to contract guarantee
18、s forspecified micronaire readings. For this purpose, it is usual practice to testonly one specimen per sample.6. Apparatus and Materials6.1 Air-Flow Instrument, calibrated in micronaire readingsor yielding numerical readings from which micronaire readingscan be computed.36.2 Micronaire Scale, appro
19、priate for instrument.NOTE 3The air instrument scale is calibrated for a specific airregulator and tube. The model number on the scale should corrrespond tothe model number of the instrument. If a regulator or tube is replaced, andthe same scale is to be used, the new parts must be of the same make
20、andmodel as those originally furnished with the instrument (1).46.3 Balance, having a capacity suitable for mass of thespecimen to be used and a sensitivity of at least 0.2 % of themass.6.4 Air Supply, to furnish the required pressure or vacuum tooperate the instrument in accordance with the manufac
21、turersinstructions.6.5 Calibration Cotton Standards, with assigned micronairereadings.7. Sampling and Selection of Specimens7.1 Take the test specimen by random sampling from thelaboratory sample prepared as directed in Practice D 1441.NOTE 4In commercial testing consider the classers sample thatrep
22、resents both sides of the bale as the laboratory sample. Take portionsfor each specimen from the end of the classers sample, to be represen-tative of all layers, or take two test specimens, one from each side of thebale.8. Conditioning8.1 Bring the laboratory sample from the prevailing atmo-sphere t
23、o moisture equilibrium for testing and check theequilibrium as directed in Practice D 1776. Preconditioning isnot necessary.NOTE 5The effect of conditioning is small for cottons having micron-aire readings below 3.5 but is appreciable for readings of 5.0 and above (2,3).9. Procedure9.1 Set up and ad
24、just the instrument as directed in themanufacturers instructions. Adjust the instrument if necessaryto secure values which check the values assigned to theInternational Calibration Cotton Standards at the beginning ofeach testing period. Make two tests with each standard cotton.If the average of the
25、 two results is not within 60.1 unit of theestablished micronaire reading, recheck the instrument and thetechnique used by the operator. Check the instrument againstthe standards again at the end of each testing period. Ifincorrect readings on the standards are obtained at the end of atesting period
26、, discard the results, recheck the instrument, andrepeat the tests.NOTE 6Built-in calibration devices and calibration plugs alone giveonly approximate results.9.2 Test the conditioned specimens in the atmosphere fortesting textiles.9.3 Remove obvious, large pieces of nonfibrous materials.Weigh out a
27、 test specimen having the mass specified for theinstrument. Place the weighed specimen in the fiber compres-sion cylinder, fluffing it with the fingers as it is packed into thecylinder to eliminate knotty balls, and being careful to place allthe fibers inside the cylinder. Insert or activate the fib
28、ercompression plunger. Turn on or activate the air, and read thevalue to the nearest 0.1 unit reading.9.4 Test two specimens.10. Calculation10.1 If the instrument readings are not in micronaire read-ings, compute micronaire readings from instrument readings inaccordance with manufacturers instructio
29、ns.10.2 Calculate the average for the two specimens tested tothe nearest 0.1 micronaire reading.11. Report11.1 State that the test was carried out as directed in ASTMTest Method D 1448.11.2 Report the following information:11.2.1 Type of material used and identification of thesamples by shipment, ma
30、rk, lot numbers or bale numbers,whichever is applicable.11.2.2 Average readings to the nearest 0.1 micronaire read-ing.11.2.3 Make, type, and model of the instrument used.12. Precision and Bias12.1 Interlaboratory Test Data5An interlaboratory test iscarried out semi-annually in connection with the I
31、nternationalCalibration Cotton Standards Program (4). The data obtainedby the five laboratories designated to establish standard valuesfor check test numbers 29, 30, and 31 in 1971 and 1972 wereused as the basis for the precision and accuracy statements.One operator at each of the five laboratories
32、tested threespecimens from each of six subsamples representing sixdifferent cottons. The subsamples for these tests were extractedfrom cotton which had been hand blended and processed intopicker laps to obtain uniform material. The components ofvariance calculated from the results of these tests and
33、 ex-pressed as standard deviations of micronaire reading are0.0628 for the single-operator component and 0.0230 for thebetween-laboratory component.12.2 PrecisionFor the components of variance in 12.1, theaverages of observed values should be considered significantlydifferent at the 95 % probability
34、 level if the differences exceedthe critical differences listed below for various number ofspecimens in the test:Critical Differences, MicronaireReadings, for the Conditions NotedA3Instruments commercially available.4The boldface numbers in parentheses refer to the list of references appended tothis
35、 test method.5ASTM Research Report No. D-13-1029. A copy is available from ASTMHeadquarters.D1448052Number of Specimensin Each AverageSingle-OperatorPrecisionBetween-LaboratoryPrecision1 0.17 0.192 0.12 0.143 0.10 0.124 0.09 0.115 0.08 0.1010 0.05 0.08AThe critical differences were calculated using
36、t = 1.960 which is based oninfinite degrees of freedom.NOTE 7The tabulated values of the critical differences should beconsidered to be a general statement particularly with respect to between-laboratory precision. Before a meaningful statement can be made abouttwo specific laboratories, the amount
37、of statistical bias, if any, betweenthem must be established with each comparison being based on recent dataobtained on randomized specimens from one sample of the material beingtested.12.3 BiasThis method for the testing of the fiber finenessof cotton is accepted internationally for commercial trad
38、ingand has no known bias when the results are controlled at thestandard level by the use of International Calibration CottonStandards.13. Keywords13.1 cotton; fineness; micronaire readingREFERENCES(1) “Revised Micronaire Fiber-Fineness Scale for Use in Testing Ameri-can Upland Cottons,” Cotton Branc
39、h, PMA, U.S. Dept. ofAgriculture,Washington, D. C., October, 1950.(2) Gates, F. R., and Jennings, E. J., “The Effect of Relative Humidity onMicronaire Readings,” Texas Research Journal, TRJOA, Vol 23, 1953,pp. 942944.(3) “Effect of Atmospheric Conditions on Testing Certain Cotton FiberProperties,” C
40、otton Branch, PMA, U. S. Dept. of Agriculture, Wash-ington, D.C., October, 1953.(4) International Calibration Cotton Standards, United States Departmentof Agriculture, Washington, D.C., Revised January 1966.ASTM International takes no position respecting the validity of any patent rights asserted in
41、 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 subject to revision at any time by the re
42、sponsible 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 Headquarters. Your comments will receive care
43、ful 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 standard is copyrighted by ASTM Internationa
44、l, 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).D1448053
