1、Designation: E2906/E2906M 13Standard Practice forAcoustic Pulse Reflectometry Examination of Tube Bundles1This standard is issued under the fixed designation E2906/E2906M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes use of Acoustic Pulse Reflecto-metry (APR) technology for examination of the internalsurface
3、of typical tube bundles found in heat exchangers,boilers, tubular air heaters and reactors, during shutdownperiods.1.2 The purpose of APR examination is to detect, locate andidentify flaws such as through-wall holes, ID wall loss due topitting and/or erosion as well as full or partial tube blockages
4、.APR may not be effective in detecting cracks with tightboundaries.1.3 APR technology utilizes generation of sound wavesthrough the air in the examined tube, then detecting reflectionscreated by discontinuities and/or blockages. Analysis of theinitial phase (positive or negative) and the shape of th
5、ereflected acoustic wave are used to identify the type of flawcausing the reflection.1.4 When proper methods of signal and data analysis aredeveloped, APR technology can be applied for sizing offlaw/blockage indications.1.5 The values stated in either SI units or inch-pound unitsare to be regarded s
6、eparately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standards.1.6 This standard does not purport to address all of thesafety con
7、cerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Perfor
8、ming NondestructiveTestingE1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recommended Practice for NondestructiveTesting Personnel Qualification and Certification3ANSI/ASNT CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel3NAS-
9、410 Certification and Qualification of NondestructiveTest Personnel43. Terminology3.1 DefinitionsSee Terminology E1316 for general termi-nology applicable to this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 acoustic pulse reflectometrya technology fordetecting, locating and ana
10、lyzing sound reflections caused bydiscontinuities and abrupt changes on the internal surface oftubes and pipes as a response to an induced acoustic signalwithin the examined structure.3.2.2 reference signala measured signal from a typicaltube in the examined bundle without flaws or blockages.Reflect
11、ions in the reference signal indicate structural featuresof the tube, probe or adaptor.3.2.3 signal-to-noise ratio (SNR)the ratio of the signalsRoot Mean Square (RMS) to RMS of the noise signal.3.2.4 output gainthe gain of the sound-source amplifier.1This test method is under the jurisdiction of AST
12、M Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.10 onSpecialized NDT Methods.Current edition approved March 1, 2013. Published March 2013. DOI: 10.1520/E2906_E2906M-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C
13、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4
14、Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http:/www.aia-aerospace.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Practice4.1 This p
15、ractice describes the use of APR technology todetect, locate and identify flaws and blockages in tube bundles.4.2 The practice describes typical APR apparatus and pro-vides guidelines for:4.2.1 APR system setup and performance verification.4.2.2 APR examination and evaluation of examination re-sults
16、 including signal analysis, indication detection, location,identification and sizing.4.2.3 Preparation of examination report.5. Significance and Use5.1 APR technology is used for detection, location andidentification of internal diameter (ID) flaws-indications andblockages in tube bundles.5.2 Reliab
17、le and accurate examination of tube bundles is ofgreat importance in different industries. On-time detection offlaws reduces a risk of catastrophic failure and minimizesunplanned shutdowns of plant equipment. Fast examinationcapability is of great importance due to reduction of mainte-nance time.5.3
18、 APR examinations are performed for quality control ofnewly manufactured tube bundles as well as for in-serviceinspection.5.4 Performing an APR examination requires access to anopen end of each tube to be examined.5.5 Flaws that can be readily detected and identified includebut are not limited to th
19、rough-wall holes, ID pitting, erosion,blockages, bulging due to creep and plastic deformation due tobending.5.6 APR can be applied to tube bundles made of metal,graphite, plastic or other solid materials with straight andcurved sections. The APR technology has been found effectiveon tubes with diame
20、ters between 12.7 mm 12 in. to 101.6 mm4 in. and lengths up to 18 metres 60 feet.5.7 Closed cracks on ID surface, without significant geo-metrical alternation on ID surface, may not be detected byAPR.5.8 APR technology can be used for flaw sizing whenspecial signal and data analysis methods are deve
21、loped andapplied.5.9 In addition to detection of flaws and blockages, APRtechnology can be applied for assessing tube ID surfacecleanliness, providing valuable information for equipmentmaintenance and improving its performance.5.10 Other nondestructive test methods may be used toverify and evaluate
22、the significance of APR indications, theirexact position, depth, dimension and orientation. These includeremote visual inspection, eddy current and ultrasonic testing.5.11 Procedures for using other NDT methods are beyondthe scope of this practice.5.12 Acceptable flaw size can be calculated using me
23、thodsof fracture mechanics and/or numerical modeling using finiteelement analysis techniques. These calculations are beyond thescope of this document.6. Basis of Application6.1 The following items are subject to contractual agree-ment between the parties using or referencing this practice.6.2 Person
24、nel QualificationIf specified in the contractualagreement, personnel performing examinations to this standardshall be qualified in accordance with a nationally and interna-tionally recognized NDT personnel qualification practice orstandard such asANSI/ASNT CP-189, SNT-TC-1A, NAS-410,or a similar doc
25、ument and certified by the employer orcertifying agency, as applicable. The practice or standard usedand its applicable revision shall be identified in the contractualagreement between the using parties.6.3 Qualification of Nondestructive Testing AgenciesIfspecified in the contractual agreement, NDT
26、 agencies shall bequalified and evaluated as described in Specification E543. Theapplicable edition of Specification E543 shall be specified inthe contractual agreement.6.4 Extent of ExaminationThe extent of examination in-cludes the entire tube bundle unless otherwise specified.6.5 Reexamination of
27、 Repaired/Re-cleaned Worked TubesReexamination of repaired/re-cleaned items is not addressed inthis practice and if required shall be specified in the contractualagreement.7. Apparatus7.1 Acoustic Pulse Reflectometry equipment includes:7.1.1 An APR probe with:7.1.1.1 A wideband sound source, usually
28、 a loudspeaker,capable of producing frequencies typically in the range of 0 to8 kHz. Pulse width should be short enough to distinguishbetween reflections generated by flaws located at a mutualdistance defined by practical requirements of the test. Thesound source level should be high enough to ensur
29、e that theweakest reflected signal of interest is above the backgroundnoise level.7.1.1.2 A probe-to-tube adaptor for matching between theprobe diameter and the ID of the tube under inspection.7.1.1.3 A microphone for measuring reflected sound waves.7.1.2 A main unit that:7.1.2.1 Generates and ampli
30、fies electric signals, typicallyperformed by a processor, Digital-to-Analog Converter (DAC)and amplifier.7.1.2.2 Sends the generated electric signals to the probessound source.7.1.2.3 Records signals produced by reflected waves andcaptured by the microphone in a format suitable for evaluation,typica
31、lly performed by a preamplifier, Analog-to-Digital Con-verter (ADC) and a processor.7.1.2.4 Stores and displays measured data.7.1.2.5 Optionally analyzes and interprets the measureddata.E2906/E2906M 1328. Calibration8.1 System calibration shall include the complete AcousticPulse Reflectometry examin
32、ation system and performed annu-ally or prior to the first use.8.2 Any change of the probe, extension cables, acousticpulse reflectometry instrument, computer, or other recordinginstruments shall require recalibration of the system, andrecalibration shall be noted on the report.8.3 Should the system
33、 be found to be out of calibrationduring the examination, it shall be recalibrated. The recalibra-tion shall be noted on the report. All tubes examined since thelast valid calibration shall be reexamined.9. System Setup and Performance Verification9.1 System setup and performance verification shall
34、beperformed prior to conducting APR examination.9.1.1 After setup a hardware test shall be conducted to makesure that all components are working.Atest measurement shallbe performed on a sample tube, and basic properties of thesignal verified, such as signal amplitude and shape, to be withinthe speci
35、fications of the manufacturer.9.1.2 APR system setup performed by adjustment of outputgain to achieve the best SNR for the particular tube geometryand noise level. This is done by increasing output gain in steps.The output gain level is considered optimal when the noisecreated by a nonlinear distort
36、ion becomes larger than thebackground noise.9.1.3 Performance verification of the system shall be con-ducted to ensure detection and sizing of flaws or blockages ofinterest prior to every APR examination. Performance verifi-cation can be done by examination of reference tube bundles.Atypical referen
37、ce tube bundle will include both flawless tubesand tubes with flaws including blockages, pits, holes andend-of-tube erosions. Performance verification is done byexamination of the tubes in the bundle and identification of allflaws.An example of a reference tube bundle is provided in theNon-Mandatory
38、 Appendix.10. Procedure10.1 Preparation for Examination:10.1.1 Verify that tube surfaces are sufficiently clean forconducting APR examination so possible discontinuities aresurface open.10.1.2 Blow out residual water.10.2 Perform measurements on each tube of the bundle byinserting the APR probes ada
39、ptor into the tube end, triggeringthe sound source, measuring reflections and storing measuredsignals into memory. Good sealing between the adaptor and thetube end should be ensured.10.3 Signal Analysis:10.3.1 Perform high pass signal filtering in the case of lowfrequency drift in the signal caused
40、by elevated low frequencynoise.10.3.2 Perform low pass signal filtering in the case of highfrequency signal oscillations caused by elevated high fre-quency noise.10.3.3 It is recommended to subtract the reference signalfrom all the measured signals to eliminate reflections caused bystructural featur
41、es, the probe or the adaptor, that are not flaw orblockage related.10.3.4 Indication DetectionDetect indications of flaws orblockages by considering recorded signals in the time domainand selecting positive and negative deviations of the signalwhich are above the noise level.10.3.5 Indication Locati
42、onEvaluate location of detectedindications by considering time-of-flight of the wave, speed ofsound, adjusted for temperature from the probe to the source ofreflection and back. Data shall be recorded as each tube ismeasured.10.4 Indication IdentificationIt is possible to identify thetype of the det
43、ected indication (through-wall holes, partial wallloss, tube blockages) by considering the form of the reflectedsignal (see Appendix X1).10.5 Indication Size CharacterizationWhen special meth-ods of signal analysis are developed, it is possible to evaluatesize of the detected indication by consideri
44、ng amplitude of thepositive and negative deviations of the signal and time durationof the signal deviation. Particularly, in the case of blockage,APR can provide information about cross-section reduction. Inthe case of through-wall hole, it is possible to determine holediameter and in the case of wa
45、ll thickness reduction as a resultof pitting or erosion, it is possible to evaluate overall, integralwall loss in the tube cross-section.11. Report11.1 A report of the examination shall be generated. Thereport shall include, at a minimum, the following information:11.1.1 Owner, location, type, seria
46、l number, and identifica-tion of component examined,11.1.2 Size, wall thickness, material type, and configurationof installed tubes,11.1.3 Tube numbering system,11.1.4 Extent of examination or tubes examined and lengthof tubes scanned,11.1.5 Personnel performing the examination, and11.1.6 Date of ex
47、amination.11.1.7 Models, types, and serial numbers of components ofthe acoustic pulse reflectometry system:11.1.7.1 Probe-to-tube adapter model/type and extensionlength,11.1.7.2 All instrument settings,11.1.7.3 Signal-to-noise ratio,11.1.7.4 Output gain,11.1.7.5 Serial number(s) of reference tube(s)
48、,11.1.7.6 Procedure usedidentification and revision, and11.1.8 Acceptance criteria used.11.1.9 Identify tubes or specific regions where there was alimited sensitivity and other areas of reduced sensitivity orother problems caused reduced reliability of the APR exami-nation.11.1.10 Results of the exa
49、mination and related sketches ormaps of the examined area.11.1.11 Other NDT examinations performed for furtherinvestigation or confirmation of test results.E2906/E2906M 13311.1.12 Description of reference bundle tube(s) used forperformance verification.12. Keywords12.1 acoustic pulse reflectometry; blockage; heat exchang-ers; through holes; tubesAPPENDIXES(Nonmandatory Information)X1. INDICATION TYPIFICATIONX1.1 It is possible to identify the type of the detectedindication (through-wall holes, partial wall loss, tube block-ages) by considering the form of t
