《BS-3424-16-1995.pdf》由会员分享，可在线阅读，更多相关《BS-3424-16-1995.pdf（10页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS 3424-16: 1995 Testing coated fabrics Part 16: Method 18. Determination of air permeability IMPORTANT NOTE. It is recommended that this Part be read in conjunction with the information in Part 0: Foreword and general introduction. Licensed Copy: sheffieldun sheffieldun, na, Wed No
2、v 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 December 1995 BSI 03-1999 The
3、 following BSI references relate to the work on this standard: Committee reference PRI/78 Draft for comment 94/342269 DC ISBN 0 580 24507 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee PRI/78, Coated fabrics, upon whic
4、h the following bodies were represented: British Apparel and Textile Confederation British Plastics Federation British Railways Board British Rubber Manufacturers Association Ltd. British Textile Technology Group Department of Health Department of the Environment (Building Research Establishment) Fu
5、rniture Industry Research Association Home Office Industrial Safety (Protective Equipment) Manufacturers Association Made-Up Textiles Association RAPRA Technology Ltd. SATRA Footwear Technology Centre Society of Motor Manufacturers and Traders Limited The following body was also represented in the d
6、rafting of the standard, through subcommittees and panels: Ministry of Defence Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 BSI 03-1999i Contents Page Committees res
7、ponsibleInside front cover Forewordii 1Scope1 2Normative references1 3Principle1 4Apparatus1 5Selection of test specimens1 6Preparation of test specimens1 7Atmosphere1 8Procedure1 9Calculation and expression of results1 10Test report2 Annex A (informative) Suitable test apparatus3 Figure A.1 Illustr
8、ation of suitable test apparatus arrangements3 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 ii BSI 03-1999 Foreword This British Standard has been prepared by Technical Committee PRI/78,
9、 Coated fabrics. Air permeability is an important factor in the performance of products such as filters, clothing, tentage, sails, parachutes, building structures and acoustical suppressers. The level of permeability may be required to be relatively high for some applications or extremely low for ot
10、hers. For some applications such as gaskets, protective equipment and airbags, the coated fabric may need to be resistant to the passage of gases even at the molecular level. In these latter instances, the methods of test in BS 903-A30 or BS 2782:Method 821 A are more appropriate. A British Standard
11、 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 cover, an
12、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 sheffieldun, na,
13、Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 BSI 03-19991 1 Scope This Part of BS 3424 describes a method for determining the air permeability of coated fabrics. It is suitable for measuring the air permeability of perforated coated fabrics used for filters, coverin
14、gs and acoustical absorbers such as car headlining where the air permeability is not less than 8 mm/s at 98 Pa. 2 Normative references This British Standard incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate po
15、ints in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standard only when incorporated in it by updating or revision. For undated references, the latest edition of the cited publication app
16、lies, together with any amendments. 3 Principle The rate of air flow through a known area of coated fabric is adjusted so that there is a known pressure drop across the fabric. 4 Apparatus 4.1 A rigidly mounted circular specimen holder, having an orifice 5 cm2, 20 cm2, 50 cm2 or 100 cm2, (i.e 25.23
17、mm 0.05 mm, 50.05 mm 0.05 mm, 79.79 mm 0.05 mm or 112.84 mm 0.05 mm diameter). 4.2 Means for clamping the test specimen, securely and without distortion in the circular specimen holder and means for preventing leakage of air from the edges of the test specimen. NOTELeakages may be measured separatel
18、y and taken into account in calculating results. 4.3 A calibrated pressure gauge or manometer, accurate to within 2 % of the recorded or indicated pressure. 4.4 A suction pump, capable of drawing a steady flow of air through the test specimen. Means shall be provided for adjusting the suction rate s
19、o that the pressure differential across the test specimen is maintained at a constant of 50 Pa, 100 Pa, 200 Pa, 500 Pa or 1 kPa. 4.5 Calibrated flow meters or volumetric counters, to indicate the velocity and volume of air passing through the test specimen. NOTE 1Measurement on the inlet and outlet
20、sides of the test specimen are advisable. NOTE 2Illustrations of suitable arrangements are given in informative Annex A. 5 Selection of test specimens Select seven test specimens, each of a size appropriate to the apparatus being used. NOTEThis usually requires a test specimen to be not less than 25
21、 mm greater in diameter than the orifice of the specimen holder (see 4.1). If the coefficient of variation of individual observations on similar materials is known, the number of tests conducted may be varied according to the relationship. n = 0.154 V2 where 6 Preparation of test specimens Pre-condi
22、tion and condition each test specimen in accordance with Part 2 of BS 3424, ensuring that each test piece is kept flat, unfolded and undisturbed, for not less than 3 h. 7 Atmosphere Ensure that the temperature, relative humidity and barometric pressure of the air surrounding the test apparatus and b
23、eing drawn into the test circuit is maintained to within 5 % of the required conditions between the beginning and end of the test. Unless otherwise specified these conditions should be those specified in BS 3424-2. 8 Procedure NOTEAdvice on checking and calibrating the apparatus is given in Annex A.
24、 Mount the test specimen in the circular specimen holder (4.1), (coated surface to low pressure side if single faced) with sufficient tension to eliminate wrinkles or creases but without distorting the fabric construction or coating. Avoid selvedges. Start the suction pump (4.4) and adjust the rate
25、of flow until the required pressure differential (see 4.4) is obtained. Record the air flow rate in litres per minute (see 4.5). Maintain the pressure differential for a further 1 min and again record the air flow rate in litres per minute. NOTEFor apparel fabrics a pressure drop of not less than 20
26、0 Pa is recommended but for most coated fabric applications the pressure differential will need to be at least 500 Pa. 9 Calculation and expression of results 9.1 Mean air flow rate and CV % Calculate the arithmetic mean of the air flow rates recorded in clause 8 and determine the coefficient of var
27、iation to the nearest 0.1 % at the 95 % confidence level using BS 5324 or BS 2846-1. nis the number of tests conducted; Vis the coefficient of variation of test results. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 2 BSI 0
28、3-1999 9.2 Air permeability Calculate the air permeability (R) in mm/s as follows: where Report the results to the nearest 2 % of R. NOTENo recent interlaboratory tests have been conducted using this method. Statements in ASTM D 737 would suggest that the variance for air permeability of coated fabr
29、ics expressed as a coefficient of variation, when the test is conducted in a single laboratory by the same operator, is typically between 3 % to 6 % and that if results differ by more than a factor of 4.7 as a critical difference using 7 test results or by a factor of 3.31 using 14 test results, the
30、 difference is statistically significant at the 95 % probability level. 10 Test report The test report shall include the following particulars: a) the description of the coated fabric tested and reference to this method of test; b) the mean air permeability; c) the number of test specimens tested; d
31、) if the coated fabric is a single faced fabric, which side of the coated fabric was exposed to the incoming air; e) confirmation of the air temperature, relative humidity and barometric pressure throughout the test; f) the pressure differential applied across the test specimen; g) any deviations fr
32、om the standard test procedure. ris arithmetic mean of the air flow rate in L/min determined at 9.1; Aarea of orifice of test assembly (see 4.1) in cm2. R r A - -167= Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3424-16:1995 BSI 03-199
33、93 Annex A (informative) Suitable test apparatus A.1 Advice on checking and calibrating the apparatus It is advisable to verify the calibration and proper functioning of the apparatus weekly, if in daily use, and prior to testing if used infrequently, and after the instrument has been moved or repai
34、red. The calibration of the instrument should be checked periodically against a primary reference standard and at intervals of not greater than 12 months. The accuracy of the pressure gauge, temperature recording devices, flow meters and psychrometers should be verified periodically and at intervals
35、 not greater than 12 months. Figure A.1 Illustration of suitable test apparatus Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BS
36、I BS 3424-16:1995 BSI 03-1999 List of references (see clause 2) Normative references BSI publications BS 903, Physical testing of rubber. BS 903-A30:1975, Determination of the permeability of rubber to gases (constant pressure method). BS 2782, Methods of testing plastics. BS 2782-8, Other propertie
37、s. BS 2782:Method 821 A:1979, Determination of the gas transmission lates of films and thin sheets under atmospheric pressure (manometric method). BS 2846, Guide to statistical interpretation of data. BS 2846-1:1991, Routine analysis of quantitative data. BS 5324:1976, Guide to application of statis
38、tics to rubber testing. Other publications ASTM D.737-75, Standard test method for iar permeability of textile fabrics1). 1) published by the American Society for Testing and Materials ASTM 1916 Race St Philadelphia, PA 19103 USA. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+0
39、0:00 2006, Uncontrolled Copy, (c) BSI BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
40、 | | | | | | | | | | | | | | | | BSI British Standards Institution BSI is the independent national 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 upd
41、ated 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 inaccuracy or ambiguity while using this Britis
42、h Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000. Fax: 020 8996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the l
43、atest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of
44、 those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information se
45、rvices are also available which give details on all its products and services. Contact the Information Centre. Tel: 020 8996 7111. Fax: 020 8996 7048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For
46、details of these and other benefits contact Membership Administration. Tel: 020 8996 7002. Fax: 020 8996 7001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the
47、 Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementin
48、g the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 020 8996 7070. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:16:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI