1、BRITISH STANDARD AEROSPACE SERIES BS 7F 34:2002 (Superseding BS 6F 34:1984) Light and medium duty linen (flax) sewing thread for aerospace purposes ICS 49.025.60 BS 7F 34:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was
2、 published under the authority of the Sector Policy and Strategy Committee 17 October 2002 BSI 17 October 2002 First published BS F 34:1919 Second edition BS 2F 34:1930 Third edition BS 3F 34:1934 Fourth edition BS 4F 34:1960 Fifth edition BS 5F 34:1975 Sixth edition BS 6F 34:1984 Seventh edition BS
3、 7F 34:2002 The following BSI references relate to the work on this standard: Draft for comment 00/707766 DC Committee reference ACE/22 ISNB 0 580 36951 X Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ACE/22, Cords, rop
4、es and threads for aerospace purposes, upon which the following bodies were represented: Linen Sewing Threads Manufacturers Association Ministry of Defence UK Defence Standardization Society of British Aerospace Companies Ltd. Amendments issued since publication Amd. No. Date CommentsBS 7F 34:2002 B
5、SI 17 October 2002 i Contents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3G e n e r a l 1 4Y a r n 2 5 Finish 2 6 Construction and properties 3 7 Identification 3 Bibliography 5 Table 1 General requirements (given in BS F 100) 1 Table 2 Construct
6、ion and properties 3BS 7F 34:2002 ii BSI 17 October 2002 Foreword This British Standard, prepared under the direction of Technical Committee ACE/22, is one of a series for textiles of a quality suitable for aerospace purposes. It supersedes BS 6F 34:1984 which is withdrawn. NOTE The previous edition
7、, BS 6F 34:1984, deleted rotproofing by the copper chrome process and required that all thread be supplied rotproofed by the pentachlorophenyl laurate (PCPL) process. This new edition incorporates all earlier amendments, updates references and improves nomenclature in line with other standards in th
8、e same series. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. WARNING NOTES This standard calls for the use of su
9、bstances and/or test procedures that may be injurious to health if adequate precautions are not taken. It refers only to technical suitability and in no way absolves either the supplier or the user from statutory obligations relating to health and safety at any stage of manufacture or use. This stan
10、dard specifies pentachlorophenyl laurate (PCPL) as the only approved rotproofing treatment for aerospace textiles. Alternative treatments are under development, and this standard will be updated to delete PCPL as soon as an approved alternative treatment for aerospace textiles is available. Summary
11、of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 5 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.BS 7F 34:2002 BSI 17 October 2002 1 1 Scope This British Standard specifies the requir
12、ements for light and medium duty linen sewing thread for aerospace purposes. NOTE The latest revision of an Aerospace Series standard is indicated by a prefix number. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated reference
13、s, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS 2087-1, Preservative treatments for textiles Specification for treatments. BS F 100, Procedure for inspection and testing of textiles for aerospace purposes
14、. BS EN ISO 2060:1995, Textiles Yarn from packages Determination of linear density (mass per unit length) by the skein method. BS EN ISO 2061, Textiles Determination of twist in yarn Direct counting method. 3 General 3.1 In addition to the requirements specified in Clause 4, Clause 5, Clause 6 and C
15、lause 7 of this standard the requirements and tests given in the latest edition of BS F 100 as specified in Table 1, shall apply. Table 1 General requirements (given in BS F 100) 3.2 Freedom from faults Threads shall have uniformity of thickness, construction, and component ply tension so that there
16、 are no visually irregular twist faults. Threads of length per unit mass less than 6 000 m/kg shall contain no thread knots. Threads of length per unit mass greater than 6 000 m/kg shall not contain more than two thread knots per package. 3.3 Length per unit mass The length per unit mass of thread s
17、hall be determined in accordance with BS EN ISO 2060:1995, Option 1. Section of BS F 100 Section title Requirements and tests 1 General All requirements 2 a Quality requirements Requirements for dyed textiles except those related to fabric intended for coating Requirements for freedom from corrosive
18、 impurities (see BS F 100, Section 4) 3 Physical tests Tests for breaking strength and extension under force 4 Chemical tests Test for residual alkali solubility If required by BS F 100, Section 2: test for conductivity of aqueous extract; test for pH value of aqueous extract; test for water soluble
19、 chloride; test for water soluble sulfate. a It is not intended that BS F 100, Section 2 tests should be performed on each thread batch. The frequency of these tests should be agreed between the Quality Assurance Authority and the thread manufacturer, BS F 100.BS 7F 34:2002 2 BSI 17 October 2002 4 Y
20、arn 4.1 The thread shall be manufactured from flax fibre (Linum usitatissimum) in a three-fold construction. 4.2 The mass of the yarn shall have been reduced by not less than 10 %, by boiling. NOTE The degree of boiling of the yarn should be determined from the manufacturers records, if available. O
21、therwise, the residual alkali solubility of the thread should be determined and should not exceed 10 %. 5 Finish 5.1 Condition of material The thread shall be supplied in one of the following conditions: a) undyed and rotproofed; b) undyed, rotproofed and wax finished; c) dyed and rotproofed; or d)
22、dyed, rotproofed and wax finished. 5.2 Dyeing Where dyeing is required, the colour shall be specified by reference to an official standard, e.g. BS 381C, or otherwise by pattern. NOTE Reference to an official standard, e.g. BS 381C is preferable. 5.3 Rotproofing The thread shall be treated with pent
23、achlorophenyl laurate (PCPL) from aqueous emulsion in accordance with BS 2087-1, normal process. 5.4 Wax finishing Where wax finishing is required, beeswax substitute microcrystalline hydrocarbon wax shall be used and the added mass due to the wax shall be (20 5) %. Prior to waxing, the thread shall
24、 have been rotproofed in accordance with 5.3. 5.5 Surface finish The thread supplied in accordance with 5.1a) and 5.1c) shall be polished, but substances which promote microbiological growth (e.g. starch or modified starch) shall not be applied.BS 7F 34:2002 BSI 17 October 2002 3 6 Construction and
25、properties 6.1 The thread shall conform to the requirements given in Table 2. Table 2 Construction and properties 6.2 The direction of final twist shall be Z. 7 Identification The thread shall be identified by the following: a) the number of this British Standard, i.e. BS 7F 34; b) the relevant desi
26、gnation number given in Table 2; c) the finish; d) the colour (where required). NOTE This identification may be codified. For example, thread No. 12 required dyed black and waxed may be identified as “BS 7F 34/No. 12/black/waxed”. Designation Nominal resultant linear density Final twist a Length per
27、 unit mass b Minimum average breaking strength unwaxed waxed tex Turns/m m/kg N N No. 12 420 275 40 2 400 5 % 110 89 No. 18 275 355 40 3 650 5 % 71 57 No. 25 200 435 40 5 050 5 % 53 43 No. 30 170 470 40 6 050 5 % 45 36 No. 35 145 510 40 7 050 5 % 36 28 No. 40 125 550 40 8 050 5 % 31 25 No. 50 100 59
28、0 40 10 100 5 % 27 21 No. 60 84 630 40 12 100 5 % 22 18 No. 70 71 690 60 14 100 5 % 16 No. 80 63 730 60 16 100 5 % 13 a The final twist shall be determined in accordance with BS EN ISO 2061. b The length per unit mass shall be determined by weighing a skein conditioned and reeled in accordance with
29、BS EN ISO 2060:1995, Option 1. The values stated for length per unit mass exclude the mass of added dye and/or finishes.4 blankBS 7F 34:2002 BSI 17 October 2002 5 Bibliography Standards publications BS 381C:1996, Specification for colours for identification, coding and special purposes.BS 7F 34:2002
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