1、BSI Standards Publication Determination of long-term radiation ageing in polymers Part 2: Procedures for predicting ageing at low dose rates PD IEC/TS 61244-2:2014National foreword This Published Document is the UK implementation of IEC/TS 61244-2:2014. It supersedes BS 7816-2:1997 which is withdraw
2、n. The UK participation in its preparation was entrusted to Technical Committee GEL/112, Evaluation and qualification of electrical insulating materials and systems. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport t
3、o 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 2014 ISBN 978 0 580 85144 5 ICS 17.240; 29.035.01 Compliance with a British Standard cannot confer immunity from legal o
4、bligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 August 2014. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TS 61244-2:2014 IEC TS 61244-2 Edition 2.0 2014-08 TECHNICAL SPECIFICATI
5、ON SPECIFICATION TECHNIQUE Determination of long-term radiation ageing in polymers Part 2: Procedures for predicting ageing at low dose rates Dtermination du vieillissement long terme sous rayonnement dans les polymres Partie 2: Mthodes pour prdire le vieillissement faible dbit de doseINTERNATIONAL
6、ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE V ICS 17.240; 29.035.01 PRICE CODE CODE PRIX ISBN 978-2-8322-1828-0 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale Warning! Make sure that you o
7、btained this publication from an authorized distributor. Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agr. PD IEC/TS 61244-2:2014 2 IEC TS 61244-2:2014 IEC 2014 CONTENTS FOREWORD. 4 1 Scope 6 2 Normative references 6 3 General . 6 4 Power law extrapolat
8、ion method . 7 4.1 Description . 7 4.2 Test procedure 7 4.3 Determination of model parameters . 7 4.4 Limitations 8 5 Superposition of time dependent data 9 5.1 Description . 9 5.2 Test procedure 9 5.3 Determination of model parameters . 10 5.4 Limitations 13 6 Superposition of DED data . 14 6.1 Des
9、cription . 14 6.2 Test procedure 14 6.3 Evaluation . 14 6.4 Limitations 15 Annex A (informative) Behaviour of polymeric materials in radiation environments . 17 Annex B (informative) Examples of use of the power law method 19 B.1 General . 19 B.2 Polypropylene filaments 19 B.3 Crosslinked polyethyle
10、ne (XLPE) . 19 Annex C (informative) Use of the superposition principle 21 Annex D (informative) Examples of use of the superposition of time dependent data . 23 D.1 Ethylene propylene (EPDM) elastomer . 23 D.2 Nitrile elastomer 23 D.3 Ethylene vinyl acetate (EVA) polymer 23 Annex E (informative) Ex
11、amples of use of the superposition of dose to equivalent damage (DED) data 26 E.1 General . 26 E.2 Neoprene cable jacket . 26 E.3 Chlorosulphonated polyethylene (CSPE) cable jacket 26 E.4 Crosslinked polyolefin (XLPO) cable insulation 26 E.5 Poly vinyl chloride (PVC) cable jacket 26 Bibliography . 3
12、0 Figure 1 Interpolation of the end-point dose (schematic), showing a plot of relative elongation at break plotted vs dose with interpolation of DED values at 0,75 and 0,5 8 Figure 2 Extrapolation of end-point dose to lower dose rates (schematic) C showing the plot of DED values vs dose rate. 8 Figu
13、re 3 Limitations Extrapolation of DED near thermal ageing limit (schematic) . 9 Figure 4 Determining shift factors a (T,0) for thermal ageing . 10 Figure 5 Superposition of data to yield master curve . 11 PD IEC/TS 61244-2:2014IEC TS 61244-2:2014 IEC 2014 3 Figure 6 Determination of activation energ
14、y E . 11 Figure 7 Determination of shift factors a (T, D) for combined thermal-radiation ageing, relative to the master curve in Figure 4 . 12 Figure 8 Fitting experimental values of a (T, D) to the empirical model Equation (2) . 13 Figure 9 Calculated DED using Equation (5) . 13 Figure 10 DED value
15、s under combined thermal-radiation conditions (schematic) . 15 Figure 11 Superposition of DED data (schematic) 15 Figure A.1 Schematic illustrating the types of dose rate effects which can occur in radiation aged polymeric materials 18 Figure B.1 Elongation at break of polypropylene irradiated in ai
16、r (from 10) 19 Figure B.2 Extrapolation of end-point dose from data in Figure B.1 . 20 Figure B.3 Dose required to reach 100 % elongation at 20 C for an XLPE cable insulation material 11 20 Figure C.1 Schematic Superposition principle for thermal ageing . 21 Figure C.2 Schematic Superposition princi
17、ple for combined thermal-radiation ageing 22 Figure D.1 Experimental data for EPDM elastomer fitted to the superposition model 24 Figure D.2 Calculated DED for 50 % compression set at 20 C . 24 Figure D.3 Calculated DED for 50 % compression set at 40 C . 25 Figure D.4 Calculated DED for e/e 0 = 0,5
18、. 25 Figure E.1 Superposition of DED data at 50 C for a neoprene cable jacket material 7 . 27 Figure E.2 Superposition of DED data for several different CSPE cable jacket materials 28 Figure E.3 Superposition of DED data for a XLPO cable insulation material 7 . 29 Figure E.4 Superposition of DED dat
19、a for PVC showing complex dose rate dependence Homogeneous oxidation data only 29 PD IEC/TS 61244-2:2014 4 IEC TS 61244-2:2014 IEC 2014 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ DETERMINATION OF LONG-TERM RADIATION AGEING IN POLYMERS Part 2: Procedures for predicting ageing at low dose rates FOREW
20、ORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the elec
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28、nts or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publicatio
29、n, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility
30、that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. In exceptional circumstances, a technical committee
31、 may propose the publication of a technical specification when the required support cannot be obtained for the publication of an International Standard, despite repeated efforts, or the subject is still under technical development or where, for any other reason, there is the future but no immediate
32、possibility of an agreement on an International Standard. Technical specifications are subject to review within three years of publication to decide whether they can be transformed into International Standards. IEC TS 61244-2, which is a technical specification, has been prepared by IEC technical co
33、mmittee 112: Evaluation and qualification of electrical insulating materials and systems. This second edition cancels and replaces the first edition published in 1996 and constitutes a technical revision. PD IEC/TS 61244-2:2014IEC TS 61244-2:2014 IEC 2014 5 This edition includes the following signif
34、icant technical changes with respect to the previous edition: a) examples and background information moved to annexes; b) examples updated with more recent references. The text of this technical specification is based on the following documents: Enquiry draft Report on voting 112/288/DTS 112/305/RVC
35、 Full information on the voting for the approval of this technical specification can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 61244 series, published under the ge
36、neral title Determination of long-term ageing in polymers, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific p
37、ublication. At this date, the publication will be transformed into an International standard, reconfirmed, withdrawn, replaced by a revised edition, or amended. PD IEC/TS 61244-2:2014 6 IEC TS 61244-2:2014 IEC 2014 DETERMINATION OF LONG-TERM RADIATION AGEING IN POLYMERS Part 2: Procedures for predic
38、ting ageing at low dose rates 1 Scope This part of IEC TS 61244, which is a technical specification, applies to procedures for predicting ageing of polymeric materials at low dose rates. The object is to present three methods which can be used to extrapolate data obtained from high dose rate experim
39、ents to the low dose rates typical of service conditions. These methods assume that homogeneous oxidation has been achieved under the test conditions. The techniques described in the following clauses are methods which have been found to be useful for a range of elastomeric, thermoplastic and thermo
40、set materials. The procedures require a considerable number of test data to enable predictions to be made under low dose rate conditions. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For da
41、ted references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60544-2, Guide for determining the effects of ionizing radiation on insulating materials Part 2: Procedures for irradiation and test IEC 61244
42、-1, Determination of long-term radiation ageing in polymers Part 1: Techniques for monitoring diffusion-limited oxidation 3 General The general guidelines of IEC 60544-2 shall be used in the selection of specimen types, radiation source, dosimetry and temperature control. All irradiations shall be c
43、arried out in air or at constant oxygen overpressure, although as noted in IEC 61244-1, oxygen overpressure techniques entail some risk of over-ageing the samples. The homogeneity of oxidation through the specimen thickness can be checked using profiling techniques such as those described in IEC 612
44、44-1. The test report shall include details of the irradiation source, dose rate, atmosphere, temperature, sample type and thickness. All of the procedures described require extensive data obtained over considerable periods of time. Each method has been found to be of practical use within its limita
45、tions, but none of the methods can be used where there is more than one mechanism operating with different apparent activation energies. The power-law extrapolation method (Clause 4) is the simplest of the predictive techniques and requires the least amount of experimental data. This procedure canno
46、t be used at dose rates low enough for thermal ageing to dominate, but appears to be valid for extrapolation of data obtained at near ambient temperatures (20 C to 30 C) for polymers such as polyolefins. Because of the limited data involved, caution should be used in extrapolating by more than a fac
47、tor of 10 in dose rate. PD IEC/TS 61244-2:2014IEC TS 61244-2:2014 IEC 2014 7 Both of the superposition methods can make use of data obtained under combined thermal/radiation ageing and are able to predict behaviour in the dose rate regime where thermal degradation is important, but require considera
48、bly more experimental data than the power-law extrapolation method. The superposition of time-dependent data (Clause 5) is not applicable to all materials; for instance, it cannot be used with materials which exhibit complex dose rate effects. Where it is applicable, the procedure does lend itself t
49、o calculation of the effects of quite complex temperature-dose rate conditions. The superposition of dose to equivalent damage (DED) data (Clause 6) can be used for most materials but, like all of the procedures, it cannot be used to extrapolate through thermal transitions of the polymer. The general behaviour of polymeric materials aged in radiation environments is described in Annex A. 4 Power law extrapolation method 4.1
