1、BS EN ISO638:2008ICS 85.040; 85.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPaper, board and pulps Determination ofdry matter content Oven-drying method(ISO 638:2008)This British Standardwas published underthe authority of theStandards Policy andStrategy
2、Committee on 30November 2008 BSI 2008ISBN 978 0 580 58856 3Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 638:2008National forewordThis British Standard is the UK implementation of EN ISO 638:2008. Itsupersedes BS EN 20638:1993 which is withdrawn.The UK participation in its pre
3、paration was entrusted to TechnicalCommittee PAI/11, Methods of test for paper, board and pulps.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsib
4、le for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 638October 2008ICS 85.040; 85.060 Supersedes EN 20638:1993 English VersionPaper, board and pulps - Determination of dry matter content
5、-Oven-drying method (ISO 638:2008)Papiers, cartons et ptes - Dtermination de la teneur enmatires sches - Mthode par schage ltuve (ISO638:2008)Papier, Pappe und Faserstoff - Bestimmung desTrockengehaltes - Wrmeschrankverfahren (ISO 638:2008)This European Standard was approved by CEN on 13 September 2
6、008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on
7、 application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Cent
8、re has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
9、Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any mean
10、s reservedworldwide for CEN national Members.Ref. No. EN ISO 638:2008: EBS EN ISO 638:2008EN ISO 638:2008 (E) 3 Foreword This document (EN ISO 638:2008) has been prepared by Technical Committee ISO/TC 6 “Paper, board and pulps“ in collaboration with Technical Committee CEN/TC 172 “Pulp, paper and bo
11、ard” the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the latest by April 2009. Attenti
12、on is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 20638:1993. According to the CEN/CENELEC Internal Regulations, th
13、e national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No
14、rway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 638:2008 has been approved by CEN as a EN ISO 638:2008 without any modification. BS EN ISO 638:2008ISO 638:2008(E) ISO 2008 All rights reserved iiiForeword ISO (
15、the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO 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 commi
16、ttee has been established has the right to be represented on that committee. International organizations, governmental 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 electrotec
17、hnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the membe
18、r bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is 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 identifyin
19、g any or all such patent rights. ISO 638 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps. This second edition cancels and replaces the first edition (ISO 638:1978), which has been technically revised. The scope has been changed to cover also paper and board instead of only pulps
20、. BS EN ISO 638:2008ISO 638:2008(E) iv ISO 2008 All rights reservedIntroduction Determination of dry matter content and moisture content are carried out for different purposes. This International Standard should be used when the dry matter content is needed to calculate the results for chemical anal
21、ysis or physical testing. An example of this is where the results of a chemical analysis for cadmium or manganese are required on the basis of the oven-dry mass of the sample. ISO 2871should be used for the purpose of determining the average moisture content and the variation in moisture content (ma
22、ximum and minimum values) of a lot. In the converting of paper and board, moisture content is important as it can have an effect on processes such as printing and copying. Moisture content can have an effect on curl and dimensional stability. ISO 41192should be used in laboratory procedures or is re
23、ferred to in other International Standards in which the concentration of an aqueous pulp suspension requires determination. BS EN ISO 638:2008INTERNATIONAL STANDARD ISO 638:2008(E) ISO 2008 All rights reserved 1Paper, board and pulps Determination of dry matter content Oven-drying method 1 Scope Thi
24、s International Standard specifies an oven-drying method for the determination of the dry matter in paper, board and pulp. The procedure is applicable to paper, board and pulp which does not contain any appreciable quantities of materials other than water that are volatile at the temperature of 105
25、C 2 C. It is used, for example, in the case of pulp, paper and board samples taken for chemical and physical tests in the laboratory, when a concurrent determination of dry matter content is required. This method is not applicable to the determination of the dry matter content of slush pulp or to th
26、e determination of the saleable mass of pulp lots. NOTE ISO 2871specifies the determination of moisture of a lot of paper and board; ISO 41193specifies the determination of stock concentration of pulps; ISO 801 (all parts)2specifies the determination of saleable mass in lots. 2 Normative references
27、The following referenced documents are indispensable for the application of this document. 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 Sampling to determine av
28、erage quality ISO 7213, Pulps Sampling for testing 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 dry matter content paper, board and pulps ratio of the mass of a test piece, after drying to constant mass at a temperature of 105C 2 C under s
29、pecified conditions, to its mass before drying NOTE The dry matter content is usually expressed as a percentage mass fraction. 3.2 constant mass paper, board and pulps mass reached by a test piece after drying at a temperature of 105 C 2 C until the difference between two successive dryings and weig
30、hings, separated in time by at least half the initial drying period, does not exceed 0,1 % mass fraction of the test piece before drying BS EN ISO 638:2008ISO 638:2008(E) 2 ISO 2008 All rights reserved4 Principle Test pieces taken from pulp, paper or board samples are weighed before and after drying
31、 to constant mass. From the mass of the test piece before and after drying, the dry matter content is calculated. 5 Apparatus 5.1 Balance, accurate to 1 mg, for weighing test pieces of 2 g and less; for larger test pieces, accurate to 0,05 % mass fraction of the original moisture-containing test pie
32、ce. 5.2 Containers, water vapour-proof, with tightly fitting lids, and made from a material (e.g. glass or plastic) not affected by the conditions of test. 5.3 Drying oven, capable of maintaining the air temperature at 105 C 2 C, and suitably ventilated. 5.4 Desiccator. 6 Sampling If it is necessary
33、 to take a sample, ensure that it is representative of the material being sampled and take special precautions to avoid any change in moisture content of the material that will be tested. Report the source of the sample and the sampling procedure used. Sampling from a lot shall be in accordance with
34、 ISO 186 for paper and board or ISO 7213 for pulps. 7 Preparation of test pieces Do not use bare hands to handle the test pieces. Handle the test pieces and weighing containers with clean, dry, rubber or polyethylene gloves or tools. For determination of dry matter content of pulp, paper or board sa
35、mples as received, place each test piece as soon as obtained in a tared container and close it immediately. From the sample, select test pieces of the required grammage which are representative of the sample. The test piece size depends on the grammage of the sample. The size can be varied from 1 g
36、to 2 g for very low grammage samples (e.g. papers) up to 50 g for high grammage samples (e.g. pulps or boards). Cut or tear the test piece into a suitable size, taking into account the method of test for which the dry matter content is to be determined. In handling the test piece, special precaution
37、s shall be taken to avoid any change in moisture content. Test pieces which have been kept in water-vapour proof containers shall be quickly cut and weighed to minimize any variation in moisture content. Prepare at least duplicate test pieces for each sample. 8 Procedure Carry out all weighings acco
38、rding to the accuracy required of the balance (5.1). Weigh a test piece in the closed, previously dried and weighed container (5.2). After weighing, open the container and place it with test piece and lid in the oven (5.3) and heat at 105 C 2 C for a sufficiently long period until constant mass is r
39、eached. The initial drying period shall be W 30 min for material of grammage u 200 g/m2and W 60 min for grammage 200 g/m2. The initial drying period, even for highly moist samples, should not be more than 16 h. The test piece is considered to have reached constant mass when the difference between tw
40、o consecutive weighings is not more than 0,1 % mass fraction of the test piece before drying. The drying period between two consecutive weighings shall be at least one-half of the minimum initial drying time. During these periods do not put any new test pieces in the oven. BS EN ISO 638:2008ISO 638:
41、2008(E) ISO 2008 All rights reserved 3After drying, fit the lid on to the container and allow the test piece to cool in the desiccator (5.4). After cooling, equalize the air pressures outside and inside the container by quickly half-opening and reclosing the lid. Weigh the container and its contents
42、. Carry out two determinations or as many as are stated in the method of test for which the dry matter content is to be determined. The results of the parallel determinations should not deviate by more than 0,5 % mass fraction from their mean. NOTE This International Standard is a reference method f
43、or determination of dry matter content based on oven dryness at 105 C. Other drying techniques (e.g. microwave and infrared drying) are available on the market, but results from those techniques do not accord with this International Standard. 9 Expression of results 9.1 Calculation Calculate the dry
44、 matter content, wdm, expressed as a percentage mass fraction, according to Equation (1): 1dm0100mwm= (1) where m0is the mass, in grams, of the test piece before drying; m1is the mass, in grams, of the test piece after drying to constant mass. Calculate the mean dry matter content of the determinati
45、ons, dmw , and express the result to the first decimal place. Moisture content can be calculated as described in Annex A. 10 Precision 10.1 Repeatability Different kinds of pulp, paper and board samples were tested in 11 different laboratories according to this International Standard. The pooled rep
46、eatability was determined and the results are shown in Table 1. Table 1 Repeatability for determination of dry matter content Sample Dry matter content % Coefficient of variation % Bleached kraft pulp 94,6 0,08 Unbleached kraft pulp 94,5 0,14 Copy paper 96,1 0,06 Uncoated paper 95,9 0,10 Carton boar
47、d 1 94,0 0,08 Carton board 2 93,8 0,15 BS EN ISO 638:2008ISO 638:2008(E) 4 ISO 2008 All rights reserved10.2 Reproducibility Different kinds of pulp, paper and board samples were tested in 11 different laboratories according to this International Standard. The results are shown in Table 2. Table 2 Re
48、producibility for determination of dry matter content Sample Dry matter content % Coefficient of variation % Bleached kraft pulp 94,6 0,27 Unbleached kraft pulp 94,5 0,32 Copy paper 96,1 0,23 Uncoated paper 95,9 0,38 Carton board 1 94,0 0,36 Carton board 2 93,8 0,34 11 Test report The test report sh
49、all contain at least the following information: a) reference to this International Standard; b) the date and place of testing; c) all information for the complete identification of the sample; d) the results, expressed as a percentage mass fraction; e) any optional points observed in the course of the test; f) any deviations from this International Standard. BS EN ISO 638:2008ISO 638:2008(E) ISO 2008 All rights reserved 5Annex A (informative) Calculation of the moisture content Calculate the m
