1、BRITISH STANDARD BS F138:1991 Specification for Polyester plain (bobbin) netting suitable for aerospace purposesBSF138:1991 This BritishStandard, having been prepared under the directionof the Aerospace Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into
2、effect on 28June1991 BSI01-2000 The following BSI references relate to the work on this standard: Committee reference ACE/54 Draft for comment90/77307DC ISBN 0 580 19439 6 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Aerospace Standards
3、 Policy Committee (ACE/-) to Technical Committee ACE/54, upon which the following bodies were represented: British Fabric Association British Rubber Manufacturers Association British Textile Employers Association Man-made Fibres Producers Committee Ministry of Defence Society of British Aerospace Co
4、mpanies Limited Society of Dyers and Colourists Amendments issued since publication Amd. No. Date CommentsBSF138:1991 BSI 01-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 General requirements 1 3 Yarn 1 4 Manufacture of netting 1 5 Finish 2 6 Construction and
5、 properties of finished netting 2 7 Dimensional stability 2 8 Identification 2 Appendix A Information to be supplied by the purchaser 3 Appendix B Determination of total hole count 3 Appendix C Faults, method of marking and acceptance limits 4 Figure 1 Determination of total hole count 3 Table 1 Gen
6、eral requirements (given in BS F100) 1 Table 2 Nominal yarn construction 2 Table 3 Construction and properties of finished netting 2 Publication(s) referred to Inside back coverBSF138:1991 ii BSI 01-2000 Foreword This BritishStandard, prepared under the direction of the Aerospace Standards Policy Co
7、mmittee, is one of a series for textiles of a quality suitable for aerospace purposes. It specifies the requirements for polyester netting for use primarily in parachute equipment. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards a
8、re responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard ha
9、s been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BSF138:1991 BSI 01-2000 1 1 Scope This BritishStandard specifies requirements for two types of polyester plain (bobbin) netting for aerospace purposes
10、. NOTEThe information to be supplied by the purchaser in the contract or order is listed in Appendix A. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. NOTEThe latest revision of an Aerospace Series Standard is indicated by a prefix number. 2 Gene
11、ral requirements 2.1 In addition to the requirements specified in clauses3 to8, the following sections and clauses of the latest edition of BS F100 shall apply (seeTable 1.) 2.2 The tenacity shall be determined when the yarn has been tested in accordance with method A of BS1932-1 except that the num
12、ber of tests required to produce a package mean shall be5. 2.3 The yarn twist shall be determined in accordance with BS2085 except that the number of tests required to produce a package mean shall be5. 2.4 The total hole count shall be determined in accordance with Appendix B. 2.5 Faults shall be cl
13、assified in accordance with Appendix C. 3 Yarn 3.1 Type The netting shall be manufactured from high tenacity, bright polyester (polyethyleneterephthalate) continuous filament yarn. 3.2 Property The nominal tenacity of the yarn shall be63cN/tex to73cN/tex. 3.3 Construction 3.3.1 The yarn shall have t
14、he nominal construction given in Table 2. 3.3.2 The warp yarn shall be twist set and relaxed. 4 Manufacture of netting The netting shall be manufactured using a plain (bobbin) net machine having a normal12 motion bobbinet. NOTEThe conventional weaving term “weft” does not apply to plain (bobbin) net
15、ting. The term “width way” is used in this specification to identify the widthwise direction of the finished netting. Table 1 General requirements (given in BS F100) Section Title Requirements and tests 1 General All requirements 2 Quality requirements Requirements for the manufacture of wide fabric
16、s Requirements for dyed textiles Requirements for dimensions and tolerances: general and wide fabrics Requirements for freedom from corrosive impurities(seesection4) Requirements for freedom from faults: method of marking and acceptance limits 3 Physical tests Tests for mass of wide fabrics Test for
17、 bursting strength: wounded burst Test for dimensional stability on heating: dry heat 4 Chemical tests If required by section2. test for freedom from corrosive impuritiesBSF138:1991 2 BSI 01-2000 Table 2 Nominal yarn construction 5 Finish 5.1 General 5.1.1 Netting1405 shall be supplied either: a) he
18、at set(see5.2) and scoured; or b) heat set(see5.2), scoured and dyed(see5.3). 5.1.2 Netting1414 shall be supplied either: a) heat set(see5.2), scoured and polyvinylacetate (PVA) finished(see5.4); or b) heat set(see5.2), scoured, dyed(see5.3) and PVA finished(see5.4). NOTEThe netting designation and
19、finish required should be stated in the contract or order(seeAppendix A). 5.2 Heat setting The netting shall be heat set at a temperature of195 5 C. 5.3 Dyeing Where dyeing is required, the colour shall be specified by reference to a BritishStandard, e.g.BS381C, or otherwise by pattern. NOTEThe colo
20、ur required should be stated in the contract or order(seeAppendix A). 5.4 Polyvinylacetate (PVA) finish Netting1414 shall be treated with polyvinylacetate (PVA), cured at a temperature of150 C to155 C, to give an added nominal mass of0.7% to1.0% on mass per unit area. Netting1405 shall not be PVA tr
21、eated. 6 Construction and properties of finished netting NOTEThe usable width of the finished netting should be as stated in the purchasers contract or order(seeAppendix A), but a usable width of920+25mm is usually supplied. When tested in accordance with clause2, the netting in the finished state s
22、hall comply with the requirements of Table 3 and clause7. 7 Dimensional stability The dimensional stability to dry heat shall not exceed2% when measured in the lengthwise direction and5% when measured in the widthwise direction. 8 Identification The netting shall be identified for ordering purposes
23、by the number of this BritishStandard, i.e.BS F138 1) , together with the relevant designation given in Table 2 and, if required dyed, the colour. NOTEThis identification may be codified. For example, netting1405 required dyed NATO green may be identified as follows: BS F138/1405 BS381C No.285. Tabl
24、e 3 Construction and properties of finished netting Netting designation Structure dtex/number of filaments (f)/turns per metre Warp Bobbin 1414 140f24S200 140f24 Spinning twist 1405 280f48S200 280f48 Spinning twist NOTE 1The tolerance on twist is 10%. NOTE 2The unit for twist is turn per metre (tpm)
25、. NOTE 3S is the direction of twist. 1) Marking BS F138 on or in relation to a product represents a manufacturers declaration of conformity, i.e.a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the resp
26、onsibility of the person making the claim. Such a declaration is not to be confused with third party certification of conformity, which may also be desirable. Netting designation Machine gauge point per25.4mm Hole count Minimum wounded bursting strength Maximum mass per unit area a Warp Width way b
27、No. kPa kPa g/m 2 1414 9 or10 26 to28 30.0 30.0 35.0 1405 8 or9 27 to29 68.0 44.0 80.0 a Does not include the extra added on mass of PVA finish. b Term used to identify the widthwise direction of finished netting(seenote to clause4).BSF138:1991 BSI 01-2000 3 Appendix A Information to be supplied by
28、the purchaser The following information shall be supplied by the purchaser in his contract or order: a) the number of this BritishStandard, i.e.BSF138; b) the netting designation(see5.1); c) the finish required(see5.1); d) the colour required(see5.3); e) the width required if other than920mm(seeclau
29、se6). Appendix B Determination of total hole count B.1 Principle The finished quality of plain netting is expressed as the sum of the hole count warp-way and bobbin-way within a25.0mm square. B.2 Apparatus B.2.1 A measuring gauge having an aperture of25.0mm square. B.3 Procedure B.3.1 Expose the net
30、ting to the standard atmosphere of652%r.h. at a temperature of20 2 C for at least16h. B.3.2 Lay the netting flat on a horizontal surface and place the measuring gauge on the netting so that one of the edges of its aperture is tangential to a row of holes in the warp direction and such that the selec
31、ted row commences with a complete hole(seeFigure 1). B.3.3 Count the number of holes in the warp-way and the number of holes in the bobbin-way. Determine the total hole count by adding the warp-way and bobbin-way hole counts together. B.3.4 Incomplete holes are to be included in the count by attribu
32、ting to them a fractional part of a complete hole, i.e.either!,“ or#. B.3.5 Repeat the procedure at not less than five different positions to obtain a representative value. B.4 Report Report the total hole count of each individual point selected and the average value of these. All dimensions are in
33、millimetres. NOTEThe example shows a22-hole net, i.e.10 holes warp-way and12 holes bobbin-way. Figure 1 Determination of total hole countBSF138:1991 4 BSI 01-2000 Appendix C Faults, method of marking and acceptance limits C.1 General Faults in textiles are essentially different from those in other a
34、erospace materials in that they are usually readily visible and, therefore, objectionable to users on appearance grounds, whether or not they involve significant loss of performance. Also, since textiles are usually required in long lengths, it is not normally convenient to cut out faulty areas. The
35、 normal requirement is careful trimming of the fabric, i.e.removal of loose threads and repair or correction of other faults, and marking of such faults as remain so as to draw them to the attention of the contractor dealing with the next stage of fabrication, when extra care in dealing with some bl
36、emishes or removal of the more serious faults is arranged. C.2 Classification of faults C.2.1 Minor faults Faults visible and liable to lead to queries but unless very frequent, not justifying special attention or penalty. C.2.2 Faults hindering fabrication Faults implying some inconvenience in subs
37、equent fabrication and so justifying temporary marking. a) Width deviation: outside the limit specified in this standard. b) Tight bobbin threads. C.2.3 Serious faults Faults affecting performance and requiring mending by the contractor. Mending shall be performed by needle and thread. Missing threa
38、ds shall be replaced, misshapen holes shall be corrected, knots and other yarn imperfections shall be taken out. a) Mechanical injuries, holes, cuts and tears if no more than eight threads are affected. b) Patches of missing threads (“holes” or “cutter outs”) if no more than eight threads are affect
39、ed. c) Single thread breaks. d) Misshapen holes. e) Slack threads. f) Stains, unless the causes are known and the effects are known to be harmless, may be removed by the use of cleaning fluid provided this does not cause a deterioration of the netting. C.2.4 Gross faults Gross faults shall not be re
40、paired and shall be cut out by the contractor. a) Mechanical injuries, holes, cuts and tears if more than eight threads are affected. b) Lines of finer or slacker holes running horizontally. c) Smashes. d) Patches of missing threads (“holes” or “cutter outs”) if more than eight threads are affected.
41、 C.3 Method of marking C.3.1 Minor faults No marking is required. C.3.2 Faults hindering fabrication and faults of lay and finish In parachute fabrics, each metre or portion of a metre affected shall be marked by sewing thread or another tag of contrasting colour securely tied into each selvedge opp
42、osite to and enclosing the extent of the fault. In all other fabrics, faults shall be marked by sewing thread or another tag of contrasting colour, securely tied into each selvedge opposite to and enclosing the extent of the fault, and visible when the fabric is in the rolled form. C.3.3 Serious fau
43、lts In parachute fabrics, each fault shall be marked by ringing or outlining its extent on the fabric surface in a marking medium of contrasting colour which shall be resistant to scouring and dyeing processes. In all other fabrics, faults shall be marked by sewing thread or another tag of constrast
44、ing colour, securely tied into each selvedge opposite to and enclosing the extent of the fault and visible when the fabric is in the rolled form. C.3.4 Gross faults There is no scope for marking gross faults. C.4 Acceptance limits NOTE 11m of fabric is deemed to be affected by the presence of a (mar
45、kable) fault or a group of faults within1m. Unless otherwise specified in the contract or order the requirements ofa) andb) shall apply. a) The lengths per100m nominal length affected by faults shall not exceed the following: 1) faults hindering fabrication and faults of lay and finish:5m; NOTE 2Suc
46、h fabric can sometimes be made acceptable by suitable re-finishing. 2) serious faults:10m; 3) gross faults: nil. b) A consignment shall be acceptable only if the total quantity affected by (markable) faults does not exceed5%.BSF138:1991 BSI 01-2000 Publication(s) referred to BS F100, Procedure for i
47、nspection and testing of textiles for aerospace purposes. BS381C, Specification for colours for identification, coding and special purposes. BS1932, Testing the strength of yarns and threads from packages. BS1932-1, Methods for determination of breaking strength and breaking extension. BS2085, Metho
48、d of test for determination of twist in yarns, direct counting method. BS F138:1991 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the inter
49、national level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:020899
