1、BRITISH STANDARD BS 6538-1: 1985 ISO 5636-1: 1984 Air permeance of paper and board Part 1: Method for determination of air permeance: general aspects of testing ISO title: Paper and board Determination of air permeance (medium range) Part 1: General method UDC 676.017.62BS6538-1:1985 This British St
2、andard, having been prepared under the directionof the Paper StandardsCommittee, was published under the authority ofthe Board of BSI and comes intoeffect on 31 January 1985 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference PAM/11 Draft for comment 83/
3、35973 DC ISBN 0 580 14032 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Paper Standards Committee (PAM/-) to Technical Committee PAM/11 upon which the following bodies were represented: British Fibreboard Packaging Association Britis
4、h Paper and Board Industry Federation (PIF) British Printing Industries Federation British Wood Pulp Association Envelope Makers and Manufacturing Stationers Association Her Majestys Stationery Office Man-made Fibres Producers Committee Ministry of Defence Paper Sack Development Association Ltd. Pir
5、a (Research Association for the Paper and Board, Printing and Packaging Industries) Post Office Society of British Printing Ink Manufacturers University of Manchester Institute of Science and Technology Amendments issued since publication Amd. No. Date of issue CommentsBS6538-1:1985 BSI 07-1999 i Co
6、ntents Page Committees responsible Inside front cover National foreword ii 0 Introduction 1 1 Scope 1 2 Field of application 1 3 References 1 4 Definition 1 5 Principle 1 6 Apparatus 1 7 Sampling 2 8 Conditioning 2 9 Preparation of test pieces 2 10 Procedure 2 11 Expression of results 2 12 Test repo
7、rt 3 Annex Conversion factors for different types of apparatus 4 Publications referred to Inside back coverBS6538-1:1985 ii BSI 07-1999 National foreword This Part of BS6538 has been prepared under the direction of the Paper Standards Committee. It is identical with ISO5636-1:1984 “Paper and board D
8、etermination of air permeance (medium range) Part1: General method”, published by the International Organization for Standardization (ISO). Further Parts of this standard are currently under consideration. Terminology and conventions. The text of the international standard has been approved as suita
9、ble for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to us
10、e a full point on the baseline as the decimal marker. Wherever the words “part of ISO5636” or “International Standard” appear, referring to this Part of this standard they should be read as “this Part of this British Standard” or “British Standard” respectively. A British Standard does not purport t
11、o 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. Cross-references International standards Corresponding British Standards ISO 1
12、86:1977 BS 3430:1980 Method for sampling for testing paper and board (Identical) ISO 187:1977 BS 3431:1973 Method for the conditioning of paper and board for testing (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4,
13、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.BS6538-1:1985 BSI 07-1999 1 0 Introduction This International Standard specifies methods of mea
14、suring the rate of flow of air through unit area of a sheet of paper or board, under unit pressure difference. The measurements may be made with any apparatus which complies with the specifications given in this International Standard. This part of ISO5636 specifies basic requirements for the appara
15、tus and general operating procedures. Other parts specify detailed requirements and operating procedures applicable to specific types of apparatus. ISO5636-2 describes the Schopper apparatus and operating procedures. 1) ISO5636-3 describes the Bendtsen apparatus and operating procedures. 2) Other pa
16、rts of this International Standard may be prepared later, provided that the apparatus complies with the specifications given in this part of ISO5636. 3) 1 Scope This part of ISO5636 specifies basic requirements for apparatus and general operating procedures for determining the air permeance of paper
17、 and board in the medium air permeance range. 2 Field of application The method is applicable to papers and boards having air permeances between1 10 2and1 10 24m/(Pas). The method is unsuitable for rough surfaced papers and boards, such as creped and corrugated papers, which cannot be securely clamp
18、ed to avoid leakage. 3 References ISO 186, Paper and board Sampling for testing. ISO 187, Paper and board Conditioning of samples. 4 Definition For the purpose of this International Standard, the following definition applies. air permeance the mean flow of air through unit area under unit pressure d
19、ifference in unit time, under specified conditions it is expressed in micrometres per pascal second1ml/(m 2 Pas)=14m/(Pas) 5 Principle Clamping a test piece between two circular gaskets or between a circular gasket and an annular flat surface, the dimensions being known in either case, with the abso
20、lute air pressure on one side of the test area of the test piece equivalent to atmospheric pressure and the difference in pressure between the two sides of the test piece maintained at a small but substantially constant value during the test. Determination of flow of air through the test area in a s
21、pecified time. NOTEIn the case of the Gurley tester, the applied pressure varies during the test due to the buoyancy effect of the cylinder, but such variation is reproducible. 6 Apparatus The apparatus shall comply with the detailed requirements given in the appropriate parts of this International
22、Standard. It is essential, however, that each type of apparatus meets the following general requirements: a) the volume shall be measurable to an accuracy of 2% of the measured value, and the time shall be measurable to an accuracy of 1% of the measured value; or b) the rate of flow shall be measura
23、ble to an accuracy of 5% of the measured value. The initial pressure difference 4)over the test piece shall be known to 2% and shall not deviate by more than5% during the measurement. It shall lie between0,7and3,0kPa. 1) ISO5636-2, Paper and board Determination of air permeance (medium range) Part2:
24、 Schopper method. 2) ISO5636-3, Paper and board Determination of air permeance (medium range) Part3: Bendtsen method. 3) Other instruments which may be considered include the Potts, Sheffield, Gurley and SCAN instruments. 4) In the Gurley test, the pressure is specified in terms of the mass and dime
25、nsions of the cylinder and the quality and level of the oil.BS6538-1:1985 2 BSI 07-1999 The test piece shall be clamped with an airtight gasket on the pressurized side of the test piece. This gasket shall not deform to such an extent that the test area of the test piece is changed by more than1%. Th
26、e test area of the test piece shall not be smaller than6cm 2 . An area of10cm 2is recommended. The area shall be known to within 2%. When water is used as the displacing medium, the air flow passing through the test piece shall be in such a direction as not to have been previously in contact with th
27、e water. The air leakage shall be checked by clamping a hard impermeable material, for example a metal foil, in the apparatus in place of the test piece. Any leakage shall be less than0,025 times the minimum air permeance measurable with a particular instrument. 7 Sampling Sampling shall be carried
28、out in accordance with ISO186. 8 Conditioning Conditioning shall be carried out in accordance with ISO187. 9 Preparation of test pieces That part of the test piece which will become the test area shall not be handled during preparation or testing. Not less than ten test pieces shall be cut and their
29、 two surfaces identified, for example top side and wire side. The minimum size of the test piece shall be such that the test piece protrudes noticeably in all directions from the clamping unit and provides the test area specified in clause6. The test area shall be free from folds, wrinkles, holes, w
30、atermarks, or defects normally not inherent in the paper or board. 10 Procedure 10.1 Test atmosphere Testing shall be carried out under the same atmospheric conditions used to condition the test pieces (see clause8). 10.2 Details of measurement The operations involved in the measurement of air perme
31、ance of each test piece shall be carried out in the manner described in the appropriate part of this International Standard. The details depend on the particular type of instrument used, but, in all cases, it is essential a) to calibrate accurately the pressure difference to be applied across the te
32、st piece; b) to ensure steady operation of the device controlling the flow of air immediately before and during the time the determinations are being made; c) to ensure absence of vibration which could affect air displacement; d) to ensure that the test piece is clamped uniformly without distortion;
33、 e) to ensure that the measurements are made with the apparatus on a level surface; f) to test half of the test pieces from one side and half from the other side. 11 Expression of results 11.1 Calculation Convert the measured values (see the Annex) to give the air permeance (P) of each test piece, i
34、n micrometres per pascal second 4m/(Pas) by means of the formula where 11.2 Arithmetic mean Calculate the arithmetic mean of the air permeance, in micrometres per pascal second, to three significant figures. If there is evidence of a significant difference between the results for each direction of a
35、ir flow through the test piece, calculate a separate arithmetic mean for each. 11.3 Standard deviation Calculate the standard deviation or coefficient of variation of the air permeance for all replicate test results to two significant figures. V is the volume of air, expressed in millilitres, which
36、passed through the test area; A is the test area, in square metres; %p is the pressure difference, in kilopascals; t is the test duration, in seconds. V 1 000A%pt -BS6538-1:1985 BSI 07-1999 3 12 Test report The test report shall include the following information: a) a reference to the appropriate pa
37、rt of ISO5636; b) the date and place of testing; c) all the information necessary for the complete identification of the sample; d) the type of instrument used; e) the temperature and relative humidity during the test; f) the number of test pieces tested; g) the pressure difference used, in kilopasc
38、als; h) the test duration, in seconds, or the flow meter range used; j) the arithmetic mean or means (see11.2); k) the standard deviation or coefficient of variation (see11.3); m) any deviation from the procedure specified.BS6538-1:1985 4 BSI 07-1999 Annex Conversion factors for different types of a
39、pparatus A.0 Introduction To obtain the air permeance of a test piece from readings obtained using a particular type of apparatus, the appropriate formulae given below should be used. There are inherent differences between different types of apparatus, for example measuring head geometry, pressure d
40、ifference etc. For this reason, the factors used in the formulae should not be used to convert readings made on one type of apparatus to equivalent readings on another. It is for this reason also that the type of apparatus used must always be reported. A.1 Conversion factors (see also clause11 for s
41、ymbols) A.1.1 Schopper apparatus a) %p =1,00kPa b) %p =2,50kPa A.1.2 Bendtsen apparatus %p =1,47kPa P =0,0113 q where q is the rate of flow of air, expressed in millilitres per minute, passing through the test area. A.1.3 Potts apparatus %p =0,98kPa P =0,0170q where q is the rate of flow of air, exp
42、ressed in millilitres per minute, passing through the test area. A.1.4 Sheffield apparatus %p = 10,3 kPa where q is the rate of flow of air, expressed in millilitres per minute, passing through the test area A, in square millimetres. If the test area is285mm 2 P =0,00568 q A.1.5 Gurley apparatus A.2
43、 Equivalent values The equivalent values on different apparatus of an air permeance of14m/(Pas) are given in the table. P V t - = P 04V , t - = Apparatus Values Schopper 1 ml/s at 1 kPa Schopper 2,5 ml/s at 2,5 kPa Bendtsen 88 ml/min at 1,47 kPa Potts 59 ml/min at 0,98 kPa Sheffield 176 ml/min at 10
44、,3 kPa and 285 mm 2 Gurley 127 s at 1,23 kPa a a Inverse relationship. P 1,62 q A - = P 127 t - =BS6538-1:1985 BSI 07-1999 Publications referred to See national foreword.BS 6538-1: 1985 ISO 5636-1: 1984 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent na
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