1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12118 : 1998 BS 278
2、2 : Part 11 : Method 1103C : 1998 The European Standard EN 12118 : 1997 has the status of a British Standard ICS 23.040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Plastics piping systems Determination of moisture content in thermoplastics by coulometryThis British Stan
3、dard, 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 March 1998 BSI 1998 ISBN 0 580 29105 7 BS EN 12118 : 1998 Amendments issued since publication Amd. No. Date Text affect
4、ed National foreword This British Standard is the English language version of EN 12118 : 1997, published by the European Committee for Standardization (CEN). This standard has the secondary identifier BS 2782 : Part 11 : Method 1103C, so that it is cross-referenced within the existing series of Brit
5、ish Standards which cover related test methods for plastics materials and plastics piping components. The UK participation in its preparation was entrusted to Technical Committee PRI/61, Plastics piping systems and components, which has the responsibility to: aid enquirers to understand the text; pr
6、esent to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained o
7、n request to its secretary. The test method supports other standards that are in preparation by CEN for the specification of plastics piping and ducting systems and components. It may be used for the revision or amendment of other national standards, but it should not be presumed to apply to any exi
8、sting standard or specification which contains or makes reference to a different test method until that standard/specification has been amended or revised to make reference to this method. Cross-references The British Standards which implement international or European publications referred to in th
9、is document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. WARNING. This British Standard, which is identical with EN 12118 : 1997, does not necessarily deta
10、il all the precautions necessary to meet the requirements of the Health and Safety at Work etc. Act 1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. Compliance with a British Standard does not of itself confer immunity
11、from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 4, an inside back cover and a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secret
12、ariat: rue de Stassart 36, B-1050 Brussels 1997 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12118 : 1997 E EUROPEAN STANDARD EN 12118 NORME EUROPE ENNE EUROPA ISCHE NORM August 1997 ICS 83.080.20; 83.140.30 Descriptors: Plastic
13、 tubes, plastics, chemical analysis, determination of content, water, coulometric methods English version Plastics piping systems Determination of moisture content in thermoplastics by coulometry Syste mes de canalisations en plastiques De termination par coulome trie de la teneur en eau dans les ma
14、tie res thermoplastiques Kunststoff-Rohrleitungssysteme Bestimmung des Feuchtegehaltes in Thermoplasten mittels Coulometrie This European Standard was approved by CEN on 1997-05-28. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving th
15、is European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (
16、English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech
17、Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 12118 : 1997 BSI 1998 Foreword This European Standard has been prepared by Technical Committee CEN/TC 155, Plastics piping
18、systems and ducting systems, the secretariat of which is held by NNI. The material-dependent parameters and/or performance requirements are incorporated in the system standard(s) concerned. This standard is one of a series of standards on test methods which support system standards for plastics pipi
19、ng systems and ducting systems. 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 February 1998, and conflicting national standards shall be withdrawn at the latest by February 1998. According to th
20、e CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, S
21、weden, Switzerland and the United Kingdom.Page 3 EN 12118 : 1997 BSI 1998 1) ppm = parts per million. 1 Scope This standard specifies a method for the determination of moisture content in thermoplastics. This method is only applicable to thermoplastics for which the melting point is below 1608C. The
22、 method is suitable for measuring the moisture content down to 0,005 %. This method determines the total moisture content in the test piece and includes surface moisture and moisture contained within the test piece. Because the test piece is converted to a molten state, it is assumed that all moistu
23、re is expelled. 2 Principle After calibration of a moisture analyser (see 4.1 and 6.2), a test piece is heated to (165 5)8C for 10 min. The oven cell and the measuring cell are flushed with dry nitrogen. In the measuring cell, the moisture reacts chemically with phosphorus pentoxide, producing phosp
24、horic acid. By electrolysis, the phosphoric acid is again decomposed into water and phosphorus pentoxide. The energy required for the electrolysis is proportional to the amount of water. NOTE. It is assumed that the following test parameters are set by the standard making reference to this standard:
25、 a) the sampling procedure (see 5.1); b) the number of test pieces (see 5.2). 3 Materials 3.1 Phosphorus pentoxide (analytical grade). 3.2 Dry nitrogen, containing less than 5 ppm 1) water content. 4 Apparatus 4.1 Equipment for reference purposes 4.1.1 Moisture analyser, with oven temperature capabl
26、e of being controlled at (165 5)8C and capable of measuring quantities of water by mass to an accuracy of within 0,1 mg, typically by use of a counter to measure energy consumption related to the mass of water involved. 4.1.2 Nitrogen supply regulator, capable of providing a flow rate of (70 10) ml/
27、min. 4.1.3 Weighing cup, of corrosion-resistant material, e.g. nickel. 4.1.4 Weighing scale, with accuracy of 0,01 mg. 4.1.5 Capillary glass tube,o f2m l capacity, with connections to suit the moisture analyser. 4.2 Alternative equipment Alternative equipment to that described in 4.1 may be used, pr
28、ovided that a correlation can be demonstrated with the results obtained using equipment conforming to 4.1. 5 Test pieces 5.1 Preparation The test piece shall comprise a portion of 0,6 g to 0,7 g from a sample of granular material or cut from an end-product. The source and form of the sample shall be
29、 as specified in the referring standard. 5.2 Number The number of test pieces shall be as specified in the referring standard. 6 Procedure 6.1 General This procedure assumes the use of a counter as described in 4.1. For other forms of read-out (see 4.2), it is necessary to modify the procedure or ca
30、lculations accordingly to suit readings obtained in place of Q b and Q c (see 6.2). 6.2 Calibration 6.2.1 Make a blank determination as follows. a) If applicable, set the counter to zero. Put the cup (4.1.3) in the oven and heat it at (165 5)8C for 10 min. b) Switch off the heater and cool by dry ni
31、trogen flow for 3 min. Then read the counter and record the count, Q b . 6.2.2 Obtain a calibration value as follows. a) Introduce into the moisture analyser, in place of a test piece, the capillary glass tube (see 4.1.5) containing 2ml of distilled water or an equivalent amount of sodium tartrate d
32、ihydrate. b) Heat the tube at (165 5)8C for 10 min. c) Read the counter and record the count, Q c . 6.2.3 Calculate the calibration factor, f c , using the following equation: f c = 0,5(Q c 2 Q b ) If the value of f c lies within the range 0,9 to 1,1, consider the test conditions to be satisfactory.
33、 NOTE. The blank value (see 6.2.1) represents the quantity of moisture introduced into the apparatus by opening the oven, and the moisture contained in the nitrogen current. 6.3 Test 6.3.1 Weigh the test piece in a dry cup (4.1.3). 6.3.2 Record the actual mass, m g , of the test piece, to the neares
34、t 0,1 mg. 6.3.3 Introduce the cup into the oven (4.1.1). 6.3.4 Keep the cup in the oven for 10 min at (165 5)8C, then switch off the heater and allow the cup to cool for the next 3 min. After this time, read the counter, and record the count, Q s .Page 4 EN 12118 : 1997 BSI 1998 6.3.5 Calculate the
35、total moisture content, m w ,b y using the following equation: m w = f c (Q s 2 Q b ) m g where f c is the calibration factor; Q b is the blank count number, in micrograms (mg); Q s is the test portion piece count number, in micrograms (mg); m g is the actual mass of the test portion piece, in grams
36、 (g); m w is the total moisture content, in (mass/mass)3 10 6 (e.g.mg/g or mg/kg). 7 Test report The test report shall include the following information: a) reference to this standard and to the referring standard; b) full identification of the test piece; c) the calibration factor, f c ; d) the tot
37、al moisture content, m w , in milligrams per kilogram (mg/kg) (see 6.3.5) or in percent mass; e) any factors which may have affected the results, such as any incidents or any operating details not specified in this standard; f) the date of test.blankBSI 389 Chiswick High Road London W4 4AL | | | | |
38、 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BSI British Standards Institution BSI is the independen
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