Common Market for Eastern and Southern Africa ≠ EDICT OF GOVERNMENT ± In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. COMESA 264 (2006) (English): Textiles - Cotton fibres - Evaluation of maturity by the air flow method COMESA HARMONISED COMESA/FDHS STANDARD 264: 2006 Textiles - Cotton fibres - Evaluation of maturity by the air flow method REFERENCE: FDHS 264:2006 Foreword The Common Market for Eastern and Southern Africa (COMESA) was established in 1994 as a regional economic grouping consisting of 20 member states after signing the co-operation Treaty. In Chapter 15 of the COMESA Treaty, Member States agreed to co-operate on matters of standardisation and Quality assurance with the aim of facilitating the faster movement of goods and services within the region so as to enhance expansion of intra-COMESA trade and industrial expansion. Co-operation in standardisation is expected to result into having uniformly harmonised standards. Harmonisation of standards within the region is expected to reduce Technical Barriers to Trade that are normally encountered when goods and services are exchanged between COMESA Member States due to differences in technical requirements. Harmonized COMESA Standards are also expected to result into benefits such as greater industrial productivity and competitiveness, increased agricultural production and food security, a more rational exploitation of natural resources among others. COMESA Harmonized Standards are developed by the COMESA experts on standards representing the National Standards Bodies and other stakeholders within the region and are approved after circulating Final Draft Harmonized Standards (FDHS) to all member states for at least three months. The assumption is that all contentious issues would have been resolved during the previous stages or that an international or regional standard being adopted has been subjected through a development process consistent with accepted international practice. COMESA Standards are subject to review, to keep pace with technological advances. Users of the COMESA Harmonized Standards are therefore expected to ensure that they always have the latest version of the standards they are implementing. This COMESA standard is technically identical to ISO 10306:1993- Textiles - Cotton fibres - Evaluation of maturity by the air flow method A COMESA Harmonized Standard does not purport to include all necessary provisions of a contract. Users are responsible for its correct application. INTERNATIONAL IS0 STANDARD 10306 First edition 1993-09-I 5 Textiles - Cotton fibres - Evaluation of maturity by the air flow method Textiles - Fibres de coton - lfvaluation de la ma twit& par la m&hode ;i courant d’air Reference number IS0 10306:1993(E) IS0 10306:1993(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (I EC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 10306 was prepared by Technical Committee ISOPC 38, Textiles, Sub-Committee SC 6, Fibre testing. Annexes A and B form an integral part of this International Standard. 0 IS0 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. International Organization for Standardization Case Postale 56 CH-1211 Geneve 20 Switzerland l l Printed in Switzerland IS0 10306:1993(E) Introduction The term “cotton fibre maturity” is commonly used to signify the relative degree of fibre wall development. The measurement of the relative degree of wall thickening is too laborious for most practical purposes, therefore the determination of the maturity of cotton fibres is done by indirect methods. A microscopic method is described in IS0 4912:1981. This method has been used as a reference method for the industrial evaluation of the maturity of cotton fibres using air flow instruments, which is the object of this standard. This page intentionally left blank INTERNATIONAL STANDARD IS0 10306:1993(E) Textiles - Cotton fibres - Evaluation of maturity by the air flow method 1 Scope 3.1 immature fibre: Fibre which, upon swelling, ei- ther assumes a spiral form or lies flat, thinly outlined and almost transparent. This International Standard specifies a method for the evaluation of the maturity of loose randomized cotton It has a wall thickness of less than one-fourth of the fibres by measuring the resistance to air flow of a plug maximum fibre width. [ISO 4912:1981] of cotton fibres under two prescribed conditions. The method is applicable to cotton taken at random from 3.2 mature fibres: Fibres, the cell walls of which bales. Laps and slivers or other sources of lint cotton have developed sufficiently so that, upon swelling, may be tested, however results may differ if fibres are they become unconvoluted and almost rod-like in taken from bales. shape. Such fibres have a wall thickness equal to or greater 2 Normative references than one-fourth of the maximum fibre width. [ISO 4912:1981] The following standards contain provisions which, 3.3 maturity ratio, M: Ratio of the degree of wall through reference in this text, constitute provisions thickening to a standard degree of thickening selected of this International Standard. At the time of publi- arbitrarily to equal 0,577. [ISO 4912:1981] cation, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged 3.4 percent maturity, P,: Average percentage of to investigate the possibility of applying the most re- mature fibres in a sample, based on the total number cent editions of the standards indicated below. of fibres. [ISO 4912:1981] Members of IEC and IS0 maintain registers of cur- rently valid International Standards. 3.5 micronaire value: Measure of the air per- meability of a mass of cotton under specified condi- IS0 139: 1973, Textiles - Standard atmospheres for tions, expressed in terms of an arbitrary scale, the conditioning and testing. so-called micronaire scale. The micronaire scale is based on a range of cottons IS0 1130:1975, Textile fibres - Some methods of to which micronaire values have been assigned by sampling for testing. international agreement. [ISO 2403:1972] IS0 2403:1972, Textiles - Cotton fibres - Determi- nation of micronaire value. 4 Principle IS0 4912:1981, Textiles - Cotton fibres - Evalu- Air is passed through a test specimen consisting of a ation of maturity - Microscopic method. plug of well-opened randomized cotton fibres. For the same mass of fibres the permeability is measured by two different compressions of the plug. For each 3 Definitions compression, air is passed through the plug at a specified rate and the pressure drop across the plug For the purposes of this International Standard, the is indicated on a pressure gauge and expressed as the definitions in IS0 4912:1981 and IS0 2403:1972 ap- height, in millimetres, of a water column. The pres- ply. The following definitions are repeated here for the sure drop obtained at low compression of the plug is convenience of the user. designated PL and the other, at high compression, is 1 IS0 10306:1993(E) designated PH. These two pressures may be used to 6.2 Weigh and test the specimen in the standard calculate a maturity ratio and fibre linear density or a atmosphere for conditioning (see IS0 139:1973). percentage of mature fibres using appropriate for- mulae. The micronaire value is determined solely from the PL value. 7 Sampling and number of specimens The sampling scheme, the number of specimens to 5 Apparatus and materials be tested and the number of measurements to be made on each specimen will normally be determined 5.1 Balance, of sufficient capacity to weigh the test by the material specification or will be agreed be- specimen required for the air flow instrument used, tween the interested parties. In the absence of any with a sensitivity of better than 0,005 g. instructions, test at least two specimens, making two tests on each. Samples of raw cotton from bales may 52. Air flow instrument (see annex A). be taken according to the method described in IS0 1130:1975. The principal parts comprising the air flow instr ument are: The mass of the test specimens shall be as specified by the manufacturer of the air flow instrument. 5.2.1 Compression cylinder, with perforated end, of such dimensions that with the specified mass of 8 Procedure specimen each cubic centimetre of the cylinder shall contain 0,191 1 g of cotton at low compression and 0,382 1 g of cotton at high compression. 8.1 Before each series of measurements, make the necessary preliminary adjustments appropriate to the 5.2.2 Means of measuring air permeability of the instrument in use (see annexes A and B). specimen, comprising for example: 8.2 Divide the weighed specimen with the fingers a) a suitable air pump; into four to six portions, tease each portion out ran- domly until about 5 cm to 7 cm in diameter and place . b) two valves or other means for controlling the flow each portion successively into the sample holder until of air through the specimen or the pressure drop the entire specimen is loaded. Carefully insert the first across the specimen in the compression cylinder; portion so as to fill in the bottom edges of the sample holder by pushing it well into the bottom of the sam- d means for setting the required rate of air flow ple holder and outwards to the edges. Take care to through the specimen and a gauge for measuring insert all the specimen and not to lose any of the fi- the air pressure drop across the specimen. bres. Insert the compression plunger and lock it in its position. Avoid fibres sticking between the cylinder NOTE 1 Details of certain commercially available instru- wall and the compression plunger. ments which comply with this specification are given in an- nexes A and B to this International Standard. The method of calibration of air flow instruments is described in 8.3 Cause air to flow through the specimen at the annex B. appropriate flow rate for the low compression of the plug and after 10 s note the reading, PL, on the pres- 53 International calibration cotton standards sure scale of the instrument to an accuracy of 1 mm l of the water column. Next cause air to flow through Reference cotton used for the calibration of air flow the specimen at the appropriate flow rate for the high instruments is described in B.2.2. compression of the plug and after 10 s note the reading, PH, on the pressure scale of the instrument 5.4 Specimen preparation apparatus to the same accuracy of 1 mm of the water column. Any blending apparatus is considered suitable if it 8.4 Remove the test specimen from the cylinder produces randomly oriented samples. and reinsert it, reversing the individual portions, and repeat the procedure given in 8.2 and 8.3. NOTE 2 Apparatus that produces webs of predominantly parallel fibres is not suitable. 8.5 Repeat the procedure given in 8.2 to 8.4 on a 6 Atmosphere for conditioning and second test specimen taken from the same sample. testing If the PL or PH readings of the two successive specimens from the same sample differ by more than 6.1 Condition test samples in the standard atmos- 5 %, it is recommended to examine a new specimen phere for 4 h in moving air or alternatively for 12 h in from the same sample and to calculate the average still air. Preconditioning is not required. readings for all specimens tested. 2