1、BSI Standards PublicationBS ISO 8791-2:2013Paper and board Determination of roughness/smoothness (air leak methods)Part 2: Bendtsen methodCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without l
2、icense from IHS-,-,-BS ISO 8791-2:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 8791-2:2013. It supersedes BS 4420:1990 (ISO 8791-2:1990) which is withdrawn.This latest edition of BS ISO 8791-2 concerning Bendtsen roughness makes reference to both electr
3、onic and variable-area flow instrumentation for the first time. In doing so new material has been included to describe the electronic instrumentation. Parts of the standard related to the variable-area flow instruments were also updated, while other parts were used verbatim from previous editions.Wi
4、th the paper industry constituting a global industry, the UK committee accepted that the standard should be available for use in the UK. However, the committees main concern is that in previous standards it was stipulated that samples of high surface roughness, sufficient to give values above 1 200
5、ml/min, were unsuitable for measurement using this method. In this edition an inconsistency now exists regarding roughness values. Whilst in the Scope the Bendsten roughness values are between 5 ml/min and 3 000 ml/min, Clause 10.2.2 states that users should not use airflows above 1 200 ml/min, and
6、thus maintains the previous editions measurement parameters.This foreword is aimed at highlighting this issue. In particular it is aimed at advising users that whilst the Scope suggests a change in what is permitted for variable-area flow instrumentation, this is not in practice carried through in t
7、he section relating to measurement parameters, which constitutes a continuation from the previous edition.The UK participation in its preparation was entrusted to Technical Committee PAI/11, Methods of test for paper, board and pulps.A list of organizations represented on this committee can be obtai
8、ned on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014ISBN 978 0 580 74528 7ICS 85.060Compliance with a
9、 British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2014.Amendments/corrigenda issued since publicationDate Text affectedCopyright British Standards Institution Provided b
10、y IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 8791-2:2013 ISO 2013Paper and board Determination of roughness/smoothness (air leak methods) Part 2: Bendtsen methodPapier et carton Dtermination de la rugosit/d
11、u liss (mthodes du dbit dair) Partie 2: Mthode BendtsenINTERNATIONAL STANDARDISO8791-2Second edition2013-09-15Reference numberISO 8791-2:2013(E)Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted wit
12、hout license from IHS-,-,-BS ISO 8791-2:2013ISO 8791-2:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical
13、, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax +
14、 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 8791-2:2013ISO 8791-2:2013(E) ISO
15、 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Apparatus . 25.1 Bendtsen tester (two types) 25.2 Variable-area flowmeter type 25.3 Electronic flowmeter type . 36 Sampling 57 Conditioning 58 Preparation of test pieces
16、. 59 Calibration and verification 59.1 Variable-area flowmeter type tester 59.2 Electronic flowmeter type tester . 510 Procedure. 510.1 Test atmosphere 510.2 Determination using variable-area flowmeter type tester . 510.3 Determination using electronic flowmeter type tester 611 Expression of results
17、 612 Test report . 6Annex A (normative) Care and maintenance of variable-area flowmeter-type Bendtsen testers . 8Annex B (normative) Calibration of capillary tubes and variable-area and electronic flowmeters 10Annex C (informative) Precision 14Bibliography .16Copyright British Standards Institution
18、Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 8791-2:2013ISO 8791-2:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (I
19、SO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, gov
20、ernmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further mainte
21、nance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention is
22、 drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or
23、 on the ISO list of patent declarations received. www.iso.org/patentsAny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.The committee responsible for this document is ISO/TC 6, Paper, board and pulps, Subcommittee SC 2, Test
24、methods and quality specifications for paper and board.This second edition cancels and replaces the first edition (ISO 8791-2:1990), which has been technically revised. In this second edition mainly editorial changes have been made to include the electronic version of the test apparatus and also pre
25、cision data has been added as an informative Annex.ISO 8791 consists of the following parts, under the general title Paper and board Determination of roughness/smoothness (air leak methods): Part 1: General method Part 2: Bendtsen method Part 3: Sheffield method Part 4: Print-surf methodNOTE Part 1:
26、 General method is considered to be redundant and will be withdrawn after Parts 2, 3 and 4 have been revised and published.iv ISO 2013 All rights reservedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking per
27、mitted without license from IHS-,-,-BS ISO 8791-2:2013INTERNATIONAL STANDARD ISO 8791-2:2013(E)Paper and board Determination of roughness/smoothness (air leak methods) Part 2: Bendtsen method1 ScopeThis part of ISO 8791 specifies a method for the determination of the roughness of paper and board usi
28、ng the Bendtsen apparatus.This part of ISO 8791 is applicable to paper and board which have Bendtsen roughness values between about 5 ml/min and 3 000 ml/min when measured with variable-area type testers and between about 50 ml/min and 5 000 ml/min when measured with electronic type testers. It is n
29、ot suitable for soft papers which allow the land to make a significant impression on the surface or for high-air-permeance papers which allow a significant flow of air to pass through the sheet, or for papers which will not lie flat under the measuring head.2 Normative referencesThe following docume
30、nts, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 186, Paper and board Sam
31、pling to determine average qualityISO 187, Paper, board and pulps Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1Bendtsen ro
32、ughnessa measure of the rate at which air will pass between a flat circular land and a sheet of paper or board when tested under specified conditions and at operating pressureNote 1 to entry: Bendtsen roughness is expressed in millilitres per minute.4 PrincipleClamping a test piece between a flat pl
33、ate and a circular metal land. Supplying air at a nominal pressure of 1,47 kPa to the space enclosed inside the land and measuring the rate of air flow between the land and the test piece. ISO 2013 All rights reserved 1Copyright British Standards Institution Provided by IHS under license with BSI -
34、Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 8791-2:2013ISO 8791-2:2013(E)5 Apparatus5.1 Bendtsen tester (two types)Bendtsen tester, which operates according to one of the following principles of measurement of air flow rate: variable-ar
35、ea flowmeter type (see 5.2). electronic flowmeter type (see 5.3).For variable-area flowmeter type testers, the pressure between the flowmeter and the measuring head is known to decrease at high air flow rates (see 10.2.2) which can reduce the accuracy of the flowmeter reading. For electronic flowmet
36、er type testers, the pressure between the flowmeter and the measuring head is automatically controlled.5.2 Variable-area flowmeter typeA standard pressure difference is created across the measuring land and the air flow rate is measured on a variable-area flowmeter. The apparatus, see Figure 1, cons
37、ists of a compressor (5.2.1) and pressure stabilizing reservoir (5.2.2) to supply air, a flowmeter (5.2.4) with a pressure controlling device (5.2.3), and a measuring head (5.2.5).Annex A gives details of care and maintenance of this type of Bendtsen tester.25134Key1 compressor2 pressure stabilizing
38、 reservoir3 pressure controlling device4 flowmeter5 measuring headFigure 1 Circuit diagram of variable-area flowmeter type test apparatus5.2.1 Compressor, capable of generating air at a pressure of about 127 kPa. If necessary, filters shall be provided to ensure that the air is clean and free from o
39、il.NOTE It is advisable to have the compressor located in a laboratory having the standard atmosphere for conditioning and testing.5.2.2 Pressure stabilizing reservoir, having a volume of not less than 10 litres, installed between the compressor and the pressure controlling device.2 ISO 2013 All rig
40、hts reservedCopyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS ISO 8791-2:2013ISO 8791-2:2013(E)5.2.3 Pressure controlling device to control the air pressure at the i
41、nlet of the flowmeter. This shall comprise a manostat weight, a pressure regulator or some means of creating a steady nominal air pressure of (1,47 0,02) kPa measured at the manostat.NOTE Most Bendtsen apparatus are provided with three interchangeable manostat weights but only the 1,47 kPa manostat
42、meets the requirement of this part of ISO 8791.5.2.4 Flowmeter. The flow rate shall be measured by variable-area flowmeters which offer optional flow rate measurements in the ranges 5 ml/min to 150 ml/min, 50 ml/min to 500 ml/min and, on some instruments, 300 ml/min to 3 000 ml/min. These three vari
43、able-area flowmeters shall be capable of being read to within 2 ml/min, 5 ml/min and 20 ml/min respectively. The variable area flowmeter may be replaced by another kind of air flowmeter having a measuring range suitable for the material measured that allows the air flow to be determined with an erro
44、r of less than 5 ml/min or 5 % whichever is greater.One capillary tube shall be provided for verifying the calibration of each variable-area flowmeter. The capillary tubes shall be within the working range of the relevant flowmeter and shall themselves be accurately calibrated against a reliable sta
45、ndard (e.g. a soap-bubble meter) under the same pressure difference as that in the measuring head (Annex B gives details of the calibration of capillary tubes and variable-area flowmeters).5.2.5 Measuring head, consisting of a circular land with an enclosed area preferably corrosion-resistant with a
46、n optically flat lower surface of 31,5 mm 0,2 mm internal diameter and 0,150 mm 0,002 mm width, and with a mass of 267 g 2 g. The tubing used to connect the head to the flowmeter shall be of rubber or plastic, 5 mm internal diameter and not more than 700 mm long.NOTE 1 A longer length of tubing will
47、 result in a significant pressure drop between the flowmeter and the measuring head.NOTE 2 On most commercial instruments the valve at the outlet of the flowmeter has two outlets. For roughness measurement the tubing is connected to the smaller diameter outlet.Because the measuring head shall be pla
48、ced on the test piece in such a manner as to avoid any indentation of the surface, it is advisable to provide a mechanical device to lower and raise the head.1)5.2.6 Flat plate, polished flat plate, preferably glass used to check for air leaks and upon which the test piece is placed for testing. The leakage between the measuring head land and the flat plate shall not exceed 5 ml/min.5.2.7 Heavy metal weight, heavy metal annulus, or other suitably shaped weight, for keeping the test piece flat around the measuring head.5.3 Electronic flowmeter typeA standard pressure difference is created acr
