1、1624669 0840899 512 I BRITISH STANDARD Plastics pipes for the conveyance of fluids under pressure Miners rule - Calculation cumulative method damage The European Standard EN IS0 13760:1998 has the status of a British Standard ICs 23.040.20 for BS EN IS0 13 760:2OOO BS 2782-11: Method L12OM.2000 NO C
2、OPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Lb24bb 0840900 Ob4 BS EN IS0 13760:2000 National foreword This British Standard is the official English language version of EN IS0 137601998. It is identical with IS0 137601998. The UK participation in its preparation was entrusted t
3、o Technical Committee PRU61, Plastics piping systems and components, which has the responsibility ta: - aid enquirers to understand the text; - present to the responsible intemationaVEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed;
4、- monitor related intemational and European developments and promulgate them in the UK A list of organizations represented on this committee can be obtained on request to its secreta.ry. It is incorporated into BS 2782-1 1 Methods of testing plastics -Part 11: Thermoplastics pipes, ftt%mgs and valve
5、s, as Method 1120M:L000, for association with related test methods for plastics materials and plastics piping components. This test method has been prepared for reference by other standards under preparation by CEN for specification of plastics piping and ducting systems and components. It has been
6、implemented to enable experience of the method to be gained and for use for other fresh applications. The responsible UK Technical Committee draws attention to the following aspects of this standard and considers it important that these aspects be taken into account as appropriate when considering f
7、resh applications of this standard or any changes to calculation procedures. The second of the principles underl.ying the method as set out in clause 4, i.e. item b), is the proportionality rule, whereby *under constant conditions the amount of damage done is proportional to the duration of the atta
8、ck“. This is not self-evident, and whilst it may be approximately tnie for metals (the field of application in which its use originated), it will be misleading when the response of a given property is both significantly non-linear with time and is serious for the given application, e.g. the creep st
9、rain of a plastics pipe under constant pressure. The third of the principles, item c), assumes that the damage from a fraction of time a of any given time is also the fraction a of the damage caused by the total time. This assumption is not necessarily correct as it folIows directly from item b), an
10、d would also cause Miners ruie to fail if the proportionality rule is not valid for the conditions of use. For the treatment of long-term data which is non-linear with time, attention is drawn to IS0 9967, Themplastics pipes - Determination of creep ratio and ta IS0 10928, Plastics piping systems -
11、Glass-reinforced thennosetting plastics (GRP) pipes and fittings - Methods for regression analaysis and their use. Annex A includes an example of an actual calculation, with base data given in Table A.l and a consequent result, expressed in the final paragraph of annex A. Attention is drawn to the i
12、nformation given in the second paragraph in A.2 that for the actual calculation of tx more decimal places were used than are given in Table A. 1. This means that if the data given is used to check the validity of a given calculation package (i.e. for an appropriate calculation sequence and rounding
13、rules for significant figures), the result may not be identical to that given in the final paragraph, and judgement may be necessary as to whether the magnitude of any deviation from the example given is excessive for the purposes of using this method. This British Standard, having been prepared und
14、er the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 Aprii Loo0 O BSI 04-2000 ISBN O 580 32570 9 Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include a
15、n annex which lists normative references to international publications with their corresponding European publications. The Briiish Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Co
16、rrespondence index“, or by using the “Find“ facility of the BSI Standards Electronic Catalogue. WARNING This British Standard: which is identical with EN IS0 13760:1998. does not necessarily detail ali the precautions necessary to meet the requirements of the Health and Safety at Work etc. Act 1974.
17、 Attention should be paid to any appropriate safety precautions and the method should be operated only be trained personnel. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance
18、 with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN IS0 title page, the EN IS0 foreword page, the IS0 title page, page ii, pages 1 to 6, an inside back cover and a back cover The BSI
19、 copyight notice displayed in this document indicates when the document was last issued. I Lb24bb 084090L TTO I EUROPEAN STANDARD NORME EUROPENNE EUROPISCHENORM EN IS0 13760 May 1998 ICs 23.4.W Descriptors: see IS0 document English version Plastics pipes for the conveyance of fluids under pressure -
20、 Miners rule - Calculation method for cumulative damage (IS0 1 3760: 1 998) Tubes en mm plastiques pour le transpoii des fluides sou8 pression - Rbgle de Miner - Mthode de calcul du cumul des dommages (IS0 13760:199) KtmtsMmhn Mr den Trsnsporl von fluiden unter Druck - Mhersche Regel - Berechnungsve
21、rahren Nr kunultative SChBdingungen (IS0 13760:1998) mis uropsan standard w appraved by CEN on 13 ay i=. CEN members are bound to compiy with the CENICENELEC Intemal Regulations which stipulate the cmditkm for gMng this European Standard the status of a natimal standard without any alteration. Up-to
22、-date lists and bibikgtaphical referemes concerning such netionai standards may be obtained on applicatiwi tothe Centrai SecreWat orlo any CEN member. This Ewopean Standard exists in three odal versions (English, French. German). A verdon in any other hguage made by translation underihe responsibili
23、ty of a CEN member into its own languageand noahed tothe Central secretariat hasthe 881i8 statusas the offidal VersionS. CEN members are the national atanderds bodies of Austria. Belgium, Czech Republk, Dem, Anland, France, Germany, Greece, Iceland, Ireland, itaiy, Luxembourg, Netherlands, Noway, Po
24、rtugal, Spain, Sweden, Switzerland and Uniied Kingdom. EUROPEAN COMMEE FOR STANARDiZAON EUROPISCHES KOMITEE FOR NORMUNG COMITB EUROPBEN DE NORMALISATION O 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN IS0 13760:1998 E EN IS0
25、 13760:1998 Foreword The text of the International Standard IS0 13760: 1998 has been prepared by Technical Committee ISOTTC 138 “Plastics pipes, fittings and valves for the transport of fluids“ in collaboration with Technical Committee CEN/TC 1 55 “Plastics piping systems and ducting systems“, the s
26、ecretariat of which is held by NNI. 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 November 1998, and conflicting national standards shall be withdrawn at the latest by November 1998. According t
27、o the CENKENELEC 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
28、, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard IS0 13760:1998 was approved by CEN as a European Standard without any modification. Lb24bb9 0840903 873 EN IS0 13760:1998 INTERNATIONAL STANDARD IS0 13760 First edition 1998-05-1 5 Plastics pipes
29、for the conveyance of fluids under pressure - Miners rule - Calculation method for cumulative damage Tubes en matires plastiques pour le transport des fluides sous pression - Rgle de Miner - Mthode de calcul du cumul des dommages Reference number IS0 13760:1998(E) Lb2qbb9 0840904 70T - EN IS0 13760:
30、1998 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for whic
31、h a technical committee 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. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all m
32、atters of electrotechnical standardization. Drat International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 137
33、60 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic materials and their accessories - Test methods and basic specifications. Annexes A, B and C of this Inter
34、national Standard are for information only. II 1624bb9 0540905 b4b 111 EN IS0 13760:1998 Plastics pipes for the conveyance of fluids under pressure - Miners rule - Calculation method for cumulative damage 1 Scope This International Standard specifies a method for calculating the maximum allowable ho
35、op stress applicable to pipes exposed to varying internal pressures and/or temperatures during their expected lifetime. This method is generally known as Miners rule. It is necessary to apply Miners rule to each failure mechanism separately. Thus, for mechanical failure due to internal pressure, oth
36、er failure mechanisms, such as oxidative or dehydrochlorinative degradative failure mechanisms, are to be neglected (assuming, of course, no interaction). A material may be used only when it is proven to conform to all failure mechanism criteria. NOTE - Miners rule is an empirically based procedure,
37、 and is only a first approximation to reality. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of the publication, the edition indicated was valid. All standards are subject to r
38、evision, and patties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 10508: 1 995, Thermopla
39、stics pipes and fittings for hot and cold water systems. 3 Symbols and abbreviated terms For the purposes of this International Standard, the following symbols and abbreviations apply: ai fraction of a year, expressed as a percentage, when referring to set of conditions “7; ti lifetime under a speci
40、fied set of conditions 3 (i= 1, 2, 3, etc.) expressed in years; tm lifetime at malfunction temperature Tm as defined in IS0 10508; tmax lifetime at maximum operating temperature Tmm as defined in IS0 10508; t0 lifetime at operating temperature To as defined in IS0 10508; tx maximum permissible time
41、of use under varying conditions, expressed in years; TYD total yearly damage, expressed as a percentage. 1 = 1624669 0840906 582 R EN IS0 13760:1998 4 Principle Miners rule is based on the following assumptions: a) The total damage a material or product is allowed to suffer from a certain type of at
42、tack is constant (100 YO). b) Under constant conditions, the damage done is proportional to the duration of the attack. The material or product will last till the 100 Oh damage level has been reached. The time needed for this is called ti, in this context expressed in years. Per year, the amount of
43、damage done is - % . This is the proportionality rule. NOTE - The amount of damage is not necessarily visible or measurable; it may, e.g., also be the passing of an induction time. c) If a material is exposed to attack for only part of a year (say ai % of the year, instead of 1 O0 % of the year), th
44、e yearly damage is not - %O but - %. This follows from the proportionality rule. 1 O0 ti 1 O0 a ti ti d) In the case of damage of the same type but under varyious sets of conditions (differing severity, temperature, pressure, stress, etc.), one after the other, the total damage per year will be the
45、combined effect of the various sets of conditions. The additivity rule states that the separate amounts of damage may be added. The result is the cumulative damage under varying conditions. 5 Procedure Calculate the total yearly damage (TYD) using the following equation: expressed as a percentage of
46、 the total permissible damage. Calculate the maximum permissible time of use fx, in years, using the following equation: 1 O0 t - X-TYD NOTE - See annex A for example calculations and annex B for the assessment of oxidative stability. 2 - I Lb24bb9 0840907 439 EN IS0 13760:1998 Annex A (informative)
47、 Examples of the use of Miners rule A.l Example of varying conditions An illustrative example is provided by the calculation of the expected service life of hot-water pipes, viz: class 2 as defined in IS0 10508. This International Standard specifies, during a 50-year service life, a temperature prof
48、ile consisting of 49 years at the standard operating temperature TO of 70 OC, 1 year at the maximum operating temperature Tmax of 80 OC and 100 h at the malfunction temperature Tm of 95 OC to allow for heater control faults. To derive the proper wall thickness (or rather the ratio SDR, .e. the diame
49、ter/wall thickness ratio), it is necessary to know the maximum permissible hoop stress in the pipe wall that will withstand the given conditions. However, the proposed class specifications state that, in the case of polybutylene for instance, a safety factor of 1,5 is to be applied to the stress at TO, a safety factor of 1,3 to the stress at Tmax and a safety factor of 1 ,O to the stress at Tm (this already being a safety factor in itself). For the actual calculation, an educated guess is made of the acceptable design stress o and the expected lif
