1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 3343:2010Reinforcement yarns Determination of twist balanceindexBS ISO 3343:2010 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 334
2、3:2010.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/42, Fibre reinforced thermosetting plastics andprepregs.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessa
3、ryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 69443 1ICS 59.100.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committ
4、ee on 31 January 2011.Amendments issued since publicationDate Text affectedBS ISO 3343:2010Reference numberISO 3343:2010(E)ISO 2010INTERNATIONAL STANDARD ISO3343Third edition2010-12-15Reinforcement yarns Determination of twist balance index Fils de renfort Dtermination de lindice dquilibre en torsio
5、n BS ISO 3343:2010ISO 3343:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the
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9、m either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedBS ISO 3343:2010I
10、SO 3343:2010(E) ISO 2010 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each m
11、ember 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. ISO collaborates closely with the International
12、Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards a
13、dopted 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. Attention is drawn to the possibility that some of the elements of this document may be the subject of p
14、atent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 3343 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13, Composites and reinforcement fibres. This third edition cancels and replaces the second edition (ISO 3343:1984), of whi
15、ch it constitutes a minor revision. The following changes have been made: a) the scope has been broadened to include all reinforcement yarns; b) the sampling clause has been deleted (the sampling standard, ISO 1886, referred to in the previous edition has been withdrawn without replacement); c) a cl
16、ause concerning conditioning and the test atmosphere has been added. BS ISO 3343:2010BS ISO 3343:2010INTERNATIONAL STANDARD ISO 3343:2010(E) ISO 2010 All rights reserved 1Reinforcement yarns Determination of twist balance index 1 Scope This International Standard specifies a method for determining t
17、he twist balance index of folded yarn and cabled yarn made from textile glass, carbon, aramid or any other reinforcement fibre. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For
18、undated references, the latest edition of the referenced document (including any amendments) applies. ISO 291, Plastics Standard atmospheres for conditioning and testing 3 Principle A yarn is arranged in an open loop of specified length and width and the number of turns the yarn makes on itself is c
19、ounted. 4 Test specimens The determination is carried out on five specimens taken consecutively from an elementary unit1 )or laboratory s2)ample . 5 Conditioning and test atmosphere No conditioning is required. However, in cases of dispute, the determination shall be carried out in one of the standa
20、rd atmospheres defined in ISO 291. 1) The elementary unit is the smallest normally commercially available entity of a given product. 2) A laboratory sample is a part of the elementary unit from which the specimen(s) will be selected for the test. A laboratory sample is taken when it is impractical t
21、o bring the elementary unit into the test laboratory. BS ISO 3343:2010ISO 3343:2010(E) 2 ISO 2010 All rights reserved6 Procedure 6.1 Unwind tangentially the first 50 m of yarn from a package in order to obtain a representative test specimen from this package. Pinch the yarn between thumb and forefin
22、ger; do not cut the yarn. 6.2 Further unwind tangentially an additional 1 m of yarn, which constitutes the first test specimen. As described in 6.1, pinch the yarn without cutting it. Let the yarn hang to form an open loop, with the two ends of the specimen held 100 mm apart. 6.3 Note the number of
23、turns, Ni, the yarn makes on itself, and the direction (S or Z) in which the loop twists. The counting may be done while untwisting the yarn. 6.4 Repeat the operation described in 6.2 five times, with the specimens immediately succeeding each other and taking care to take the yarn near the package i
24、n order to avoid any loss of twist. Note the result as described in 6.3. 7 Expression of results The twist balance index, Ei, of the yarn is represented by the number of turns, Ni, the yarn makes on itself: Ei= NiThe result of the determination of the twist balance index is the arithmetic mean of th
25、e values obtained for the five specimens tested, rounded to the first decimal place. 8 Test report The test report shall include the following information: a) a reference to this International Standard; b) all details necessary for complete identification of the sample tested; c) the method used to
26、unwind the yarn; d) the result of the determination (twist balance index and direction of the twist in the loop) and, if required, the result for each specimen; e) details of any operations not specified in this International Standard, as well as details of any incidents which might have affected th
27、e results; f) the date of the test. BS ISO 3343:2010BS ISO 3343:2010ISO 3343:2010(E) ICS 59.100.10 Price based on 2 pages ISO 2010 All rights reserved This page deliberately left blankBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standar
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