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1、BRITISH STANDARD BS 4650:1970 Incorporating Amendment No. 1 Method for The determination of mesh breaking load of netting for fishing Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 This British Standard, having been approved by
2、 the Ropes and Cordage Industry Standards Committee, was published under the authority of the Executive Board on 18 December 1970 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference RCT/8 Draft for comment 69/5368 ISBN 580 06155 8 Co-operating organizati
3、ons The Ropes and Cordage Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Board of Trade British Railways Board British Tug Owners Association
4、Chamber of Shipping of the United Kingdom Cotton Twine Manufacturers Association Council of British Manufacturers of Petroleum Equipment Department of Employment and Productivity Docks and Harbour Authorities Association Federation of Soft Fibre Associations* Hard Fibre Cordage Institute* Home Offic
5、e (Civil Defence Training Branch) Lloyds Register of Shipping London Master Stevedores Association Ministry of Defence (Air Force Dept.) Ministry of Defence (Army Dept.) Ministry of Defence (Navy Dept.) Ministry of Technology Synthetic Cordage Manufacturers Association The industrial organizations m
6、arked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Man-made Fibres Federation British Trawlers Federation Ltd. Department of Agriculture and Fisheries for Scotland Federati
7、on of British Trawler Owners Grimsby Net Manufacturers Association Herring Industry Board Ministry of Agriculture, Fisheries and Food Scottish Inshore White Fish Producers Association Ltd. Scottish Trawlers Association Amendments issued since publication Amd. No.Date of issueComments 2993May 1979Ind
8、icated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 BSI 10-1999i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2Definitions1 3Principle1 4Apparatus1 5Sampling1 6Prep
9、aration of specimens1 7Requirements for testing2 8Number of tests2 9Test procedure2 10Calculation and expression of results2 11Report2 Appendix A SamplingInside back cover Figure 1 Mounting of a mesh by pins3 Figure 2 Mounting of a mesh by loops3 Figure 3 Preparation of specimen for determination of
10、 the knot breaking load4 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 ii BSI 10-1999 Foreword This standard makes reference to the following British Standards: BS 1051, Glossary of terms relating to the conditioning and testi
11、ng of textiles. BS 1610, Methods for the load verification of testing machines. BS 4674, Methods for the determination of the breaking load and knot breaking load of netting yarns for fishing nets. Technical Committee 38, “Textiles”, of the International Organization for Standardization (ISO) agreed
12、 at its meeting in 1960 to a proposal from Germany that a specialist sub-committee be appointed to deal with textile products for fishing nets. This action arose from the increasing interest in standards matters being evinced by the Food and Agriculture Organization of the United Nations and other i
13、nternational bodies concerned with deep sea fishing. It had become evident that there was a need for ISO to examine the subject of fishing nets and produce such Recommendations as were required to co-ordinate, on an international basis, the activities of the fishing industries of the maritime nation
14、s. The ISO sub-committee decided that urgent attention should be given to terminology, designation of nets and netting yarns and to methods of hanging nets and cutting them to shape. The Ropes and Cordage Industry Standards Committee appointed a technical committee to organize the UK contribution to
15、 the ISO work and to develop as British Standards such ISO Recommendations as were relevant to the UK industry. This British Standard is based on ISO 1806 (with which it is in complete conformity) and is one of a number that will cover the aspects being investigated by the ISO sub-committee. A Briti
16、sh Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are 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
17、 cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffi
18、eldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 BSI 10-19991 1 Scope This British Standard deals with the method of determining the mesh breaking load of netting for fishing. Tests may be carried out in both the dry and wet state, but tests in the wet state are
19、 considered to be particularly appropriate in indicating the behaviour of the netting in use. 2 Definitions1) For the purposes of this British Standard the following definitions apply: 2.1 mesh breaking load the breaking load, equal to the maximum load applied to a mesh observed during a breaking te
20、st 2.2 dry mesh breaking load the breaking load of a specimen under the specified dry state conditions 2.3 wet mesh breaking load the breaking load of a specimen under the specified wet state conditions 2.4 time-to-break the time, in seconds, taken to reach the mesh breaking load measured from the m
21、oment of application of the load 3 Principle A mesh is extended in dry or wet state until one of the knots or joints reaches the load at rupture. The test is performed using suitable apparatus that records or indicates the applied load. The testing machine shall be operated at such a rate that the a
22、verage time-to-break of a group of specimens will fall within specified time limits. 4 Apparatus The following apparatus is required: 1) Tensile testing machine of either the constant rate of elongation, the constant rate of load or the constant rate of traverse type. Constant rate of elongation mac
23、hines are preferred. a) The clamps of the tensile testing machines shall be replaced by pins of stainless material which stand at right angles to the direction of pull. These shall be of sufficient strength and have a diameter suitable for the mesh size. Alternatively loops of netting yarn heavier t
24、han that of the netting may be used. It is necessary to use these loops if the meshes are very small. b) It shall be possible to regulate the distance between the pins so that netting of different mesh openings can be submitted to the test. c) The maximum error of the indicated load at any point in
25、the range in which the machine is used shall not exceed 1 % in accordance with BS 16102) Grade A. Check the accuracy of the graduated scale of the apparatus dynamically, for example by means of calibrated springs of appropriate characteristics. d) The testing machine shall be capable of testing mesh
26、 specimens having different mesh openings. e) All testing machines shall include facilities for producing different rates of loading in order to break specimens in the specified average time-to-break. 2) Equipment for producing and maintaining the standard atmosphere for testing (see 7.1). 3) Equipm
27、ent in which specimens can be immersed in water preparatory to wet testing. 4) Stop watch or interval timer. 5 Sampling Test specimens shall be selected at random from the netting so as to be representative of the whole (see Appendix A). 6 Preparation of specimens To prevent untwisting of the loose
28、ends the following procedure shall be followed: 6.1 Netting with small meshes. Cut a sample of netting with a size of 3 3 meshes. The mesh strength shall be determined on the central mesh. 6.2 Netting with large meshes. Cut the loose ends of the sample mesh as far as possible from the knots or joint
29、s. Whenever possible, melting instead of cutting is preferred. 1) Symbolic abbreviations of the parameters defined have been omitted pending discussion by ISO/TC 38 of the general subject. 2) BS 1610 “Methods for the load verification of testing machines”. Licensed Copy: sheffieldun sheffieldun, na,
30、 Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 2 BSI 10-1999 6.3 The specimen shall be placed in the standard atmosphere for testing (see 7.1). 7 Requirements for testing 7.1 Atmosphere for testing. All specimens to be tested in the dry state shall be exposed to the sta
31、ndard atmosphere for testing described in BS 10513) until they have reached equilibrium. For netting of man-made fibres a period of 24 hours exposure is generally sufficient. Where it is not suitable to carry out the tests in the standard atmosphere the tests shall be carried out immediately after r
32、emoval of the samples from the standard atmosphere. 7.2 Testing in the wet state 7.2.1 All specimens to be tested in the wet state shall be immersed in tap water without wetting agents at 20 2 C for a period of not less than 12 hours. Surplus water shall be shaken off. 7.2.2 By agreement between the
33、 parties, a shorter wetting time with the addition of a wetting agent may be used. The specimens shall be immersed for one hour in a solution of wetting agent in water at a temperature of 20 2 C. A shorter time of immersion is allowed if it can be shown that the specimen is completely wetted in less
34、 than 1 hour. 7.3 Time-to-break. The mean duration of test should be 20 3 seconds. It shall be determined by preliminary tests. 8 Number of tests At least 20 single tests on each piece of netting shall be carried out, unless otherwise agreed between the purchaser and the supplier. If a distinct conf
35、idence interval for the main value is prescribed, as many additional tests shall be carried out as necessary to secure this confidence interval. 9 Test procedure 9.1 Check that the pins or loops of the testing machine are properly aligned and parallel so that the subsequent application of force to t
36、he specimen will not cause any angular deflection. 9.2 Mount the specimen in the testing machine over the pins or in the loops in such a way that its knots do not touch the pins or loops (see Figure 1 and Figure 2). 9.3 Apply the force to reach the prescribed mean time-to-break. 9.4 Wet samples shou
37、ld be tested immediately after removal from water (see 7.2.1). 9.5 If a sample does not break at one of the knots or joints, this test shall be discarded. 9.6 Discard all observations obtained on specimens of which the loose ends of the mesh slip in the knots or the joints dissolve. Such a test shal
38、l be repeated with a new specimen. The number of observations discarded as directed above should be noted. 9.7 If more than ten knots of the twenty meshes tested slip the method of mesh testing described in this standard should not be used. It should be replaced by the method of testing the knots of
39、 the netting (see BS 46744) by fastening all four ends in the holding devices of the testing machines. If the meshes are too small to ensure that all four ends of the knot are gripped by the holding devices, the knots around the knot to be tested shall be opened (see Figure 3). NOTEThe results of su
40、ch knot breaking load tests are not comparable with the results of mesh breaking load tests, the latter always giving lower values than knot breaking load tests. 10 Calculation and expression of results 10.1 Average mesh breaking load is equal to breaking load being expressed in decanewtons5). Calcu
41、late the average breaking load to four significant figures and round it off to three significant figures. 10.2 If necessary the coefficient of variation and the confidence interval may calculated by recognized statistical methods. 11 Report The report shall state: 1) that the tests were performed in
42、 accordance with this British Standard, 2) date of testing, 3) description of the netting (type of material, type of fibre, type of knot, mesh size and preparation), 4) type and capacity of testing machine used, the type of holding devices employed and the range of identification, 5) the sampling me
43、thod employed, 6) number of specimens tested, 7) the average breaking load in decanewtons, 3) BS 1051, “Glossary of terms relating to the conditioning and testing of textiles”. 4) BS 4674, “Methods for the determination of the breaking load and knot breaking load of netting yarns for fishing nets”.
44、5) 1 daN (decanewton) = 1.02 kgf. sum of observed breaking loads number of observations - - Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 BSI 10-19993 8) any deviation of the test procedure, and, if required, 9) the coefficien
45、t of variation of the breaking load and confidence interval. Figure 1 Mounting of a mesh by pinsFigure 2 Mounting of a mesh by loops Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 4 BSI 10-1999 Figure 3 Preparation of specimen
46、for determination of the knot breaking load Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 BSI 10-1999 Appendix A Sampling Samples, each to provide the required number of test specimens, shall be taken from the consignment or d
47、elivery being tested by a convenient and representative system of sampling. The number of samples taken shall be not less than 10 unless agreed between the purchaser and the supplier so as to ensure satisfactory representation of the consignment. Samples should be taken in such a manner that the use
48、fulness of the consignment or the sample part of it is not appreciably affected. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:58:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4650:1970 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent n
49、ational body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards 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 in