1、BS EN 15856:2010ICS 19.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDNon-destructivetesting Acousticemission Generalprinciples of AE testingfor the detection ofcorrosion withinmetallic surroundingfilled with liquidThis British Standardwas published under th
2、eauthority of the StandardsPolicy and StrategyCommittee on 31 January2010 BSI 2010ISBN 978 0 580 58908 9Amendments/corrigenda issued since publicationDate CommentsBS EN 15856:2010National forewordThis British Standard is the UK implementation of EN 15856:2010.The UK participation in its preparation
3、was entrusted to TechnicalCommittee WEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct applicati
4、on.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 15856:2010EUROPEAN 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 co
5、rrosion within metallic surrounding filled with liquid Essais non destructifs - Emission acoustique - Principes gnraux des contrles par mission acoustique pour la dtection de la corrosion dans une enceinte mtallique remplie de liquide Zerstrungsfreie Prfung - Schallemissionsprfung - Allgemeine Grund
6、stze der Schallemissionsprfung zum Nachweis von Korrosion innerhalb von mit Flssigkeit gefllten metallischen Umschlieungen 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 givi
7、ng this 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 CEN Management Centre or to any CEN member. This European Standard exists in three official ver
8、sions (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 CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgiu
9、m, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMIT
10、TEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, 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: EBS EN 15856:2010EN 15856:2
11、010 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Personnel qualifications .55 General 55.1 Introduction 55.2 Test preparation 55.3 Sensors .55.4 Source location .55.5 Preliminary information 65.6 Written instruction requirements .66 Instrumentation .77 T
12、esting .77.1 Sensor positions .77.2 Test detection threshold 87.3 Background noise 97.4 In-situ verification .97.5 Apparent acoustic emission velocity 97.6 Performing the test 108 Interpretation of results . 108.1 Data evaluation 108.2 Tank grading 109 Documentation 1010 Safety regulations 11BS EN 1
13、5856:2010EN 15856:2010 (E) 3 Foreword This document (EN 15856:2010) 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
14、 text or by endorsement, at the latest by July 2010, and conflicting national standards shall be withdrawn at the latest by July 2010. 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 responsibl
15、e for identifying any or all such patent rights. 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, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, F
16、rance, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15856:2010EN 15856:2010 (E) 4 1 Scope This European Standard describes acoustic
17、 emission testing (AT) on metallic surroundings filled with liquids for the detection of corrosion processes that are active at the 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
18、 regarding the condition of the test object and a recommendation regarding the maximum allowable duration of the follow-on service 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 procedu
19、re described within this standard provides testing of the complete bottom, the tank shell up to the filling height and in case of 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
20、regarding active sources. An ongoing corrosion process, such as general corrosion and localized corrosion defined in EN ISO 8044, 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 detecte
21、d at the time of test. 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 references, the latest edition of the referenced document (including any amendments) applies. EN
22、473, Non-destructive testing Qualification and certification of NDT personnel General principles 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 1330-9
23、:2009, 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 Part 2: verificat
24、ion of operating characteristics EN 13554, Non-destructive testing Acoustic emission General principles EN ISO 8044:1999, Corrosion 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/
25、IEC 17025:2005) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 1330-1:1998, EN 1330-2:1998, EN 1330-9:2009 and EN ISO 8044:1999 apply. BS EN 15856:2010EN 15856:2010 (E) 5 4 Personnel qualifications It is assumed that acoustic emission testing is perf
26、ormed by qualified and capable personnel. In order to prove this qualification, it is recommended to certify the personnel in 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 o
27、f degradation of the component under test as a result of corrosion. The recommended duration of the service period following 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 param
28、eter has been altered. The final test result shall not be affected by external or internal noise sources. The testing service 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 sou
29、rces shall be ensured. 5.2 Test preparation AE originating from corrosion propagates through both the liquid and the structure. 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 pos
30、ition of sensors mounted onto the tank shell at least by 1 m. When testing flat bottomed storage tanks (FBST) the tank operation 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 p
31、lace and, if operated, the heater shall be shut down. The necessary time period varies depending on the tank size and the stock 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 kH
32、z to 80 kHz. When wave propagation through the metal is used, the sensing frequency band is usually in the range from 100 kHz 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
33、 instruction. The sensors may be directly attached to the structure using magnetic devices or suitable adhesive. The effectiveness 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 S
34、ource location The location of AE sources is based on delta t measurement. In case of tank floor testing two rows of sensors 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 d
35、iameter. The location error is smaller near the centre area and increases as the AE source approaches the annular ring. If the 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 annul
36、ar ring. BS EN 15856:2010EN 15856:2010 (E) 6 The same principle applies to the evaluation regarding active corrosion of 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
37、floating roof increases. Waves propagate through liquid and metal from the source to the sensors and perhaps also on different 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 infor
38、mation necessary for performing the test. This shall include the following, as relevant and available: a) Customer nominated on-site test co-ordinator; b) Tank information: identification, manufacturer, year of manufacturing, serial number, capacity, shell height, diameter, thermal insulation, stock
39、 product, roof type, bottom type, foundation, internal coating, internal installation, cathodic protection, tank history 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, tempera
40、ture, filling height, sludge level, water bottom; d) Potential external and internal noise interference sources. 5.6 Written 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
41、 indication of the purpose of the test and limitations if any; b) sensor type, frequency and manufacturer; c) method of 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
42、 used; h) number of sensors required and the sensor arrangement; i) description of equipment verification procedure; j) 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.
43、g. shape, size, minimum number of located events); o) post-test analysis procedure; BS EN 15856:2010EN 15856:2010 (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 A
44、E system consists of sensors and equipment for signal conditioning 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 every channel: a) AE burst count; b) appropriate parameter indicating
45、the background noise; c) burst signal peak amplitude; d) burst signal duration; e) burst signal rise time; f) burst 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 frequen
46、cy analysis. The test instrumentation shall: h) store all the acquired data; and i) provide an on-line location display 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 positi
47、ons 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 requirement, that the distance between the sensors distributed equally around the circumference shal
48、l not exceed 15 m. Due to the fact that manholes, nozzles, welds and other structural details have to be taken into account when selecting the sensor positions, a reduced maximum distance of 13 m has proven to be applicable. With this value it is possible to shift positions as required by the struct
49、ure and to stay within the limit of 15 m. The number of sensors applied shall not be less than six per row. The distance of a sensor to a weld or a reinforcing plate shall not be less than 200 mm. BS EN 15856:2010EN 15856:2010 (E) 8 The first row of sensors shall be set at a level of approximately 1 m above the bottom. The second row of sensors is usually set at a level of 4 m to 6 m with positions directly above the first row sensors
