1、BRITISH STANDARDBS EN 15495:2007Non Destructive testing Acoustic emission Examination of metallic pressure equipment during proof testing Zone location of AE sourcesThe European Standard EN 15495:2007 has the status of a British StandardICS 17.160; 19.100g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g5
2、0g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 15495:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 20
3、07ISBN 978 0 580 54634 1National forewordThis British Standard is the UK implementation of EN 15495:2007.The UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained on request to it
4、s secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN ST
5、ANDARDNORME EUROPENNEEUROPISCHE NORMEN 15495November 2007ICS 17.160; 19.100English VersionNon Destructive testing - Acoustic emission - Examination ofmetallic pressure equipment during proof testing - Zone locationof AE sourcesEssais non destructifs - Emission acoustique - Vrificationdes quipements
6、mtalliques sous pression pendantlpreuve - Localisation par zone des sources dEAZerstrungsfreie Prfung - Schallemission - Prfung vonmetallischen Druckgerten whrend der Beanspruchung -Zonenortung von SchallemissionsquellenThis European Standard was approved by CEN on 30 September 2007.CEN members are
7、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 application to the
8、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 Centre has the same stat
9、us 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, Portugal,Romania, Sl
10、ovakia, 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 2007 CEN All rights of exploitation in any form and by any means reservedworldwide
11、for CEN national Members.Ref. No. EN 15495:2007: EEN 15495:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Personnel Qualifications.4 5 General5 5.1 General5 5.2 Application of load.5 5.3 Sensors.5 5.4 Zone location5 5.5 Preliminary information 6 5.
12、6 Written instruction requirements.6 6 Instrumentation7 7 Testing 7 7.1 Pre-Test Measurements .7 7.1.1 General7 7.1.2 Wave propagation7 7.1.3 Determination of maximum allowed sensor spacing.8 7.2 Test steps .10 7.2.1 General Guidelines 10 7.2.2 In situ verification 10 7.2.3 Background Noise .10 7.2.
13、4 Equipment Pressurisation 10 8 Interpretation of results 11 8.1 General11 8.2 Test stop criteria11 8.2.1 Test stop during the initial proof loading11 8.2.2 Test stop during subsequent loadings .11 8.3 AE zone grading criteria .11 9 Documentation.12 Bibliography 13 EN 15495:2007 (E) 3 Foreword This
14、document (EN 15495:2007) has been prepared by Technical Committee CEN/TC 138 “Non Destructive testing”, the secretariat of which is held by AFNOR. 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 M
15、ay 2008, and conflicting national standards shall be withdrawn at the latest by May 2008. Attention 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 righ
16、ts. According to the CEN/CENELEC Internal Regulations, the 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, Ita
17、ly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 15495:2007 (E) 4 1 Scope The purpose of this standard is to describe the methods for conducting an acoustic emission (AE) examination of
18、 metallic pressure equipment during acceptance pressure testing using a zone location procedure. General principles of Acoustic Emissions are described in EN 13554. The objectives of the AE testing are to provide 100 % volumetric testing to define and grade zones of the structure which are acoustica
19、lly active with burst type AE. The method should be regarded as supplementary to planar location. Planar location provides the source identification and characterisation. Zone location may also be applied in such cases where location of AE sources by planar location procedures according to EN 14584
20、is not possible. The method identifies the need for further evaluation or follow-up by other NDT in localized zones. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated ref
21、erences, the latest edition of the referenced document (including any amendments) applies. EN 1330-1:1998, Non destructive testing - Terminology - Part 1: List of general terms EN 1330-2:1998, Non destructive testing - Terminology - Part 2: Terms common to the non-destructive testing methods EN 1330
22、-9:2000, Non-destructive testing - Terminology - Part 9: Terms used in acoustic emission testing EN 13477-1, Non-destructive testing - Acoustic emission - Equipment characterisation - Part 1: Equipment description EN 13477-2, Non-destructive testing - Acoustic emission - Equipment characterisation -
23、 Part 2: Verification of operating characteristic EN 14584, Non-destructive testing - Acoustic emission - Examination of metallic pressure equipment during proof testing Planar location of AE sources 3 Terms and definitions For the purpose of this European Standard, the terms and definitions given i
24、n EN 1330-1:1998, EN 1330-2:1998 and EN 1330-9:2000 apply. 4 Personnel Qualifications It is assumed that acoustic emission testing is performed by qualified and capable personnel. To prove this qualification, it is recommended to certify the personnel in accordance with EN 473. NOTE For pressure equ
25、ipment see Directive 97/23/EC, Annex 3.1.3: “For pressure equipment in categories III and IV, the personnel must be approved by a third party organization recognized by a Member State.“ EN 15495:2007 (E) 5 5 General 5.1 General The main target of the AE test is to identify and monitor zones of high
26、acoustic emission activity and intensity caused by phenomena, e.g. crack growth and yielding, generated by the applied load to the equipment. The properties and structural state of the material, the type and magnitude of the applied stress and stress rate are significant factors affecting the emissi
27、on. All zones showing significant activity shall be completely evaluated by other NDT methods. Evaluation according to EN 14584 may help to reduce the area to inspect. 5.2 Application of load The application of the load to the equipment shall be made using internal pressure following the procedure s
28、pecified in the relevant Product Standard. The rate of the application of pressure shall be established so as to avoid burst signal overlap. The pressurising system shall permit pressurisation at a steady controllable rate and shall allow the pressure to be held constant at the hold points. The pres
29、surisation rate would not normally exceed 1 % of the test pressure per minute for pneumatic and 5 % of the test pressure per minute for the hydraulic test. The intermediate hold periods, if necessary according the AE activity or the pre-defined pressure schedule, are normally 5 min to 10 min. The fi
30、nal hold period at the test pressure shall have a minimum duration of 15 min. Intermediate hold periods are strongly recommended, especially if pressurisation rates exceed 0,5 % per minute for pneumatic or 2 % per minute for hydraulic tests. Prior to starting the test, all the necessary actions shal
31、l be taken to identify and to reduce potential sources of extraneous noise. Depending on the results of the initial loading, it may be required to reduce the load to working pressure or lower, followed by re-pressurisation. 5.3 Sensors The frequency range shall be chosen so that the expected AE has
32、sufficient energy in the chosen frequency range and the test result is unaffected by external noise sources. The most commonly used frequency range is 100 kHz to 300 kHz. Lower frequency monitoring allows detection at greater distances and high frequency monitoring provides improved rejection of ext
33、ernal noise. The equipment surface below the sensors shall be prepared to ensure the maximum coupling efficiency. The sensor couplant shall be as specified in the written test instruction. The sensors may be directly attached to the structure using magnetic devices or suitable adhesive. The effectiv
34、eness and reliability of the acoustic couplant shall be verified. The characteristics of the type of the acoustic couplant used shall not affect the structure adversely. 5.4 Zone location Zone location assigns each event producing at least one hit to the zone of the first-hit channel. Successive hit
35、s are assumed to belong to the same event as long as they arrive within the event definition time. The event definition time is a programmable time interval, which starts with the arrival of the first-hit of an event. The event definition time is determined during test set-up using a Hsu-Nielsen or
36、another appropriate artificial source and is set so that the source is correctly assigned only to the closest sensor. It is essential for this type of location that all noise sources are well controlled. EN 15495:2007 (E) 6 5.5 Preliminary information Prior to the test, the AE Test Organisation shal
37、l collect the following information: a) relevant Product Standard; b) type of equipment or structure and material characteristics and specifications; c) design- and test pressure; d) working- and test temperature; e) assembly and/or layout drawings with sufficient details of the structure; f) materi
38、al specifications, including heat treatment; if applicable g) proposed pressure/stress application sequence; h) potential acoustic noise interference sources and the isolating mechanism applied; i) where possible, locations of known discontinuities and the general results of prior NDT. 5.6 Written i
39、nstruction requirements The AE Test Organisation shall provide a written test instruction, which shall include but not necessarily be restricted to the following: a) Test object (description and/or drawing, including area of interest and purpose of test); b) limitations if any; c) sensor type, frequ
40、ency and manufacturer; d) method of sensor attachment; e) type of acoustic couplant used; f) type of surface preparation; g) type of AE equipment used with the main characteristics and settings; h) energy measurement method to be used; i) sensor location maps representing the structure or part of it
41、; j) description of equipment verification procedure; k) description of the in-situ verification (see 7.2.2); l) sequence of pressurisation; m) recorded data and recording method; n) available on-line presentation of data; o) real time evaluation criteria; p) post analysis procedure with adopted fil
42、tering technique if used; EN 15495:2007 (E) 7 q) final report requirements; r) qualification/certification of the personnel; s) value of KZ ,( for definition see Figure 1)from the relevant Product Standard if available. 6 Instrumentation An AE system consists of sensors and equipment for signal cond
43、itioning and processing and for displaying and recording data according to EN 13477-1. The AE instrument shall be capable of measuring at least the following parameters on all channels: a) AE burst count; b) Burst signal peak amplitude; c) Burst signal duration; d) Burst signal rise time; e) Burst s
44、ignal energy; f) Arrival time; and on external inputs pressure and/or other stress parameters. To allow a real time control of the pressure equipment under test, the test instrumentation shall: Store all the acquired AE data and the external parameter(s). Provide an on-line activity vs channel displ
45、ay. Provide an on-line activity vs zone display. Provide an on-line display of AE data and pressure. To assist the online evaluation it is recommended that the instrumentation provides data allowing real time AE noise identification. Online grading of zones is also recommended. The AE system operati
46、ng characteristics shall be verified according to EN 13477-2. 7 Testing 7.1 Pre-Test Measurements 7.1.1 General The requirements listed in EN 14584 apply for a setup that uses both, planar and zone location. The following text is to be observed where planar location is not used. 7.1.2 Wave propagati
47、on Attenuation measurements shall be performed on the structure to determine the maximum sensor spacing. The measurements shall be performed with the test fluid in the pressure equipment using the Hsu-Nielsen source. If the Hsu-Nielsen source saturates the measurement chain, a lower energy artificia
48、l source shall be EN 15495:2007 (E) 8 used up to the 20e (20 times the wall thickness) distance. The curve obtained shall be adjusted to correspond with the original Hsu-Nielsen source. The attenuation and wave velocity shall be measured using two sensors mounted in a region of the pressure equipmen
49、t away from nozzles, manways, etc. The shadowing effect of nozzles and ancillary attachments shall be quantified and transmission through the test fluid shall be taken into consideration. 7.1.3 Determination of maximum allowed sensor spacing The maximum distance between adjacent sensors is 1,5 times the threshold distance dthr. The threshold distance is the distance where the amplitude of the Hsu-Nielsen source is equal to the evaluation threshold Ae. The evaluation threshold Aeis defined as the amplitude of the Hsu-Nielsen source at the distance of 0,02
