DIN EN 15856-2010 Non-destructive testing - Acoustic emission - General principles of AE testing for the detection of corrosion within metallic surrounding filled with liquid Germa.pdf

1、May 2010 Translation by DIN-Sprachendienst.English price group 9No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 19.

2、100!$bJ“1636139www.din.deDDIN EN 15856Non-destructive testing Acoustic emission General principles of AE testing for the detection of corrosion withinmetallic surrounding filled with liquidEnglish translation of DIN EN 15856:2010-05Zerstrungsfreie Prfung Schallemissionsprfung Allgemeine Grundstze de

3、r Schallemissionsprfung zum Nachweis von Korrosioninnerhalb von mit Flssigkeit gefllten metallischen UmschlieungenEnglische bersetzung von DIN EN 15856:2010-05Essais non destructifs Emission acoustique Principes gnraux des contrles par mission acoustique pour la dtection de lacorrosion dans une ence

4、inte mtallique remplie de liquideTraduction anglaise de DIN EN 15856:2010-05www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.1305.10 DIN EN 15856:2010-05 National foreword This standard has been prepared by Technical Committee CEN/T

5、C 138 “Non-destructive testing” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Working Committee NA 062-08-23 AA Ultraschallprfung. 2 A comma is used as the decimal marker. EUROPEAN

6、 STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15856 January 2010 ICS 19.100 English Version Non-destructive testing Acoustic emission General principles of AE testing for the detection of corrosion within metallic surrounding filled with liquid Essais non destructifs Emission acoustique Principes gnr

7、aux des contrles par mission acoustique pour la dtection de la corrosion dans une enceinte mtallique remplie de liquide Zerstrungsfreie Prfung Schallemissionsprfung Allgemeine Grundstze der Schallemissionsprfung zum Nachweis von Korrosion innerhalb von mit Flssigkeit gefllten metallischen Umschlieun

8、gen This European Standard was approved by CEN on 28 November 2009. 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

9、 references concerning such national standards may be obtained on 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 translation under the responsibility of a CEN m

10、ember into its own language and notified to the CEN Management Centre has the same status as theofficial versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,Finland, France, Germany, Greece, Hungary, Iceland, Irelan

11、d, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17,

12、B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15856:2010: EEN 15856:2010 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Personnel qualifications .55 General 55.1 In

13、troduction 55.2 Test preparation 55.3 Sensors .55.4 Source location .55.5 Preliminary information 65.6 Written instruction requirements .66 Instrumentation .77 Testing .77.1 Sensor positions .77.2 Test detection threshold 87.3 Background noise 97.4 In-situ verification .97.5 Apparent acoustic emissi

14、on velocity 97.6 Performing the test 108 Interpretation of results . 108.1 Data evaluation 108.2 Tank grading 109 Documentation 1010 Safety regulations 11DIN EN 15856:2010-05 EN 15856:2010 (E) 3 Foreword This document (EN 15856:2010) has been prepared by Technical Committee CEN/TC 138 “Non-destructi

15、ve 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 July 2010, and conflicting national standards shall be withdrawn at the latest by July 2010.

16、 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 rights. According to the CEN/CENELEC Internal Regulations, the national standards organizatio

17、ns of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,

18、 Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DIN EN 15856:2010-05 EN 15856:2010 (E) 4 1 Scope This European Standard describes acoustic emission testing (AT) on metallic surroundings filled with liquids for the detection of corrosion processes that are active at t

19、he time of the test. It is applicable to metallic storage tanks, such as those used in the chemical and petrochemical industry. The results provide a qualitative statement regarding the condition of the test object and a recommendation regarding the maximum allowable duration of the follow-on servic

20、e period, based on the AT indications and additional information in order to characterize the AT indications. In the case of flat bottomed storage tanks (FBST) the procedure described within this standard provides testing of the complete bottom, the tank shell up to the filling height and in case of

21、 a floating roof tank also the roof sheets in contact with the stored liquid. As for every application of acoustic emission testing, the measured data contain information regarding active sources. An ongoing corrosion process, such as general corrosion and localized corrosion defined in EN ISO 8044,

22、 leading to progressive loss of wall thickness will be detected. A corrosion process which has stopped does not produce acoustic emission and will therefore not be detected at the time of test. 2 Normative references The following referenced documents are indispensable for the application of this do

23、cument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 473, Non-destructive testing Qualification and certification of NDT personnel General principles EN 1330-1:1998, Non-destructive

24、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 1330-9:2009, Non-destructive testing Terminology Part 9: Terms used in acoustic emission testing EN 13477-1, Non-destructive testing Ac

25、oustic emission Equipment characterisation Part 1: Equipment description EN 13477-2, Non-destructive testing Acoustic emission Equipment characterisation Part 2: verification of operating characteristics EN 13554, Non-destructive testing Acoustic emission General principles EN ISO 8044:1999, Corrosi

26、on of metals and alloys Basic terms and definitions (ISO 8044:1999) EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 1330-1:1998, EN

27、1330-2:1998, EN 1330-9:2009 and EN ISO 8044:1999 apply. DIN EN 15856:2010-05 EN 15856:2010 (E) 5 4 Personnel qualifications It is assumed that acoustic emission testing is performed by qualified and capable personnel. In order to prove this qualification, it is recommended to certify the personnel i

28、n accordance with EN 473. 5 General 5.1 Introduction Evaluation of the AE data shall be done according to an established grading system, providing grades relating to the rate of degradation of the component under test as a result of corrosion. The recommended duration of the service period following

29、 the test is with respect to the service condition prior to and at the time of the test. This recommendation is invalid, if the storage product or any other major service parameter has been altered. The final test result shall not be affected by external or internal noise sources. The testing servic

30、e provider has to communicate the demands regarding tank preparation to the tank operator. Proper support by the plant personnel for identification and elimination of noise sources shall be ensured. 5.2 Test preparation AE originating from corrosion propagates through both the liquid and the structu

31、re. Where corrosion testing of tanks utilises wave propagation through the liquid stock product, the minimum filling level of the tank to be tested shall exceed the highest position of sensors mounted onto the tank shell at least by 1 m. When testing flat bottomed storage tanks (FBST) the tank opera

32、tion shall be static before the test in order to reduce internal noise to a minimum. No product shall be fed into or taken out of the tank, no internal circulation shall take place and, if operated, the heater shall be shut down. The necessary time period varies depending on the tank size and the st

33、ock product. Twenty-four hours is usually sufficient. 5.3 Sensors When wave propagation through the liquid is used, the sensor frequency band is usually in the range from 20 kHz to 80 kHz. When wave propagation through the metal is used, the sensing frequency band is usually in the range from 100 kH

34、z to 300 kHz. 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 effecti

35、veness 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 Source location The location of AE sources is based on delta t measurement. In case of tank floor testing two rows of sensors

36、 and wave propagation through the liquid shall be used. When evaluating the floor condition regarding active corrosion, the location error is normally within 10 % of the tank diameter. The location error is smaller near the centre area and increases as the AE source approaches the annular ring. If t

37、he height of first row sensors (see 7.1) is changed as a result of the presence of sludge or internal structure, then the location error increases, especially near to the annular ring. DIN EN 15856:2010-05 EN 15856:2010 (E) 6 The same principle applies to the evaluation regarding active corrosion of

38、 the floating roof. The location error of the roof testing is normally within 15 % of the tank diameter. The error increases when the distance of the second row of sensors from the floating roof increases. Waves propagate through liquid and metal from the source to the sensors and perhaps also on di

39、fferent paths. Therefore the planar location error on the tank shell is normally within 15 % of the sensor spacing. 5.5 Preliminary information The tank operator shall provide information necessary for performing the test. This shall include the following, as relevant and available: a) Customer nomi

40、nated on-site test co-ordinator; b) Tank information: identification, manufacturer, year of manufacturing, serial number, capacity, shell height, diameter, thermal insulation, stock product, roof type, bottom type, foundation, internal coating, internal installation, cathodic protection, tank histor

41、y including NDT and repairs, assembly drawings with sufficient details of the structure; c) AE test information: intended date and expected conditions such as stock product, temperature, filling height, sludge level, water bottom; d) Potential external and internal noise interference sources. 5.6 Wr

42、itten instruction requirements The AE test organisation shall provide a written test instruction, which shall include but not necessarily be restricted to the following: a) explicit indication of the purpose of the test and limitations if any; b) sensor type, frequency and manufacturer; c) method of

43、 sensor attachment; d) type of acoustic couplant used; e) type of surface preparation; f) type of AE equipment used with the main characteristics; g) energy measurement method to be used; h) number of sensors required and the sensor arrangement; i) description of equipment verification procedure; j)

44、 description of in-situ verification; k) description of test performance; l) recorded data and recording method; m) available on-line presentation of data; n) cluster parameters (e.g. shape, size, minimum number of located events); o) post-test analysis procedure; DIN EN 15856:2010-05 EN 15856:2010

45、(E) 7 p) final report requirements; q) qualification/certification of the personnel. The test instruction shall be prepared in accordance with EN 473 and EN 13554. 6 Instrumentation An AE system consists of sensors and equipment for signal conditioning and processing and for displaying and recording

46、 data according to EN 13477-1. The AE instrument shall be capable of measuring at least the following parameters on every channel: a) AE burst count; b) appropriate parameter indicating the background noise; c) burst signal peak amplitude; d) burst signal duration; e) burst signal rise time; f) burs

47、t signal energy; g) arrival time. In addition to the acquired burst signal parameters, waveform data of each detected hit on any available AE channel enables evaluation by signal frequency analysis. The test instrumentation shall: h) store all the acquired data; and i) provide an on-line location di

48、splay for preliminary on-site reporting on the performed test. The AE system performance check (including sensors) shall be performed according to EN 13477-2. 7 Testing 7.1 Sensor positions For use of wave propagation through liquid, e.g. testing flat bottomed storage tanks (FBST), the following applies: The number of sensors necessary for a certain tank diameter is derived from the