1、Designation: E1930/E1930M 12E1930/E1930M 17Standard Practice forExamination of Liquid-Filled Atmospheric and Low-PressureMetal Storage Tanks Using Acoustic Emission1This standard is issued under the fixed designation E1930/E1930M; the number immediately following the designation indicates the yearof
2、 original adoption or, in the case of revision, the year of 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. Scope*1.1 This practice covers guidelines for acoustic emission (AE
3、) examinations of new and in-service aboveground storage tanksof the type used for storage of liquids.1.2 This practice will detect acoustic emission in areas of sensor coverage that are stressed during the course of the examination.For flat-bottom tanks these areas will generally include the sidewa
4、lls (and roof if pressure is applied above the liquid level). Theexamination may not detect flaws on the bottom of flat-bottom tanks unless sensors are located on the bottom.1.3 This practice may require that the tank experience a load that is greater than that encountered in normal use. The normalc
5、ontents of the tank can usually be used for applying this load.1.4 This practice is not valid for tanks that will be operated at a pressure greater than the examination pressure.1.5 It is not necessary to drain or clean the tank before performing this examination.1.6 This practice applies to tanks m
6、ade of carbon steel, stainless steel, aluminum and other metals.1.7 This practice may also detect defects in tank linings (for example, high-bulk, phenolics and other brittle materials).1.8 AE measurements are used to detect and localize emission sources. Other NDT methods may be used to confirm the
7、 natureand significance of the AE indications (s). Procedures for other NDT techniques are beyond the scope of this practice.1.9 Examination liquid must be above its freezing temperature and below its boiling temperature.1.10 Superimposed internal or external pressures must not exceed design pressur
8、e.1.11 Leaks may be found during the course of this examination but their detection is not the intention of this practice.1.12 UnitsThe values stated in either SI units or inch-pound units are to be regarded as standard. The values stated in eachsystem may not be exact equivalents; therefore, each s
9、ystem shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standards.1.13 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to es
10、tablish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 8.1.14 This international standard was developed in accordance with internationally recognized principles on standardizationes
11、tablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestructive Te
12、stingE650 Guide for Mounting Piezoelectric Acoustic Emission SensorsE976 Guide for Determining the Reproducibility of Acoustic Emission Sensor ResponseE1106 Test Method for Primary Calibration of Acoustic Emission Sensors1 This practice is under the jurisdiction ofASTM Committee E07 on Nondestructiv
13、e Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic EmissionMethod.Current edition approved June 15, 2012June 1, 2017. Published July 2012June 2017. Originally approved in 1997. Last previous edition approved in 20072012 asE1930 - 07.E1930 - 12. DOI: 10.1520/E1930_E1930M-12
14、.10.1520/E1930_E1930M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standar
15、d and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases o
16、nly the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E1316 Terminology f
17、or Nondestructive ExaminationsE1781 Practice for Secondary Calibration of Acoustic Emission SensorsE2374 Guide for Acoustic Emission System Performance Verification2.2 ANSI/ASNT Standard:Recommended Practice ASNT SNT-TC-1A for Qualification and Certification of Nondestructive Testing Personnel3ANSI/
18、ASNT CP-189 Standard for Qualification and Certification of NDT Personnel32.3 ASME Standard:Section V, Article 12, Boiler metal storage tanks; above ground storage tanksANNEX(Mandatory Information)A1. SPECIFICATIONS FOR APPARATUSA1.1 Instrumentation SpecificationsA1.1.1 AE sensors shall be resonant
19、in a 100 to 200 kHz frequency band.A1.1.2 Sensors shall have a peak sensitivity greater than -77 dB (referredSensor acceptance sensitivity shall be established usinga published procedure such as Test Method E1106 to 1or Practice E1781volt per microbar, determined by face-to-face ultrasonicexaminatio
20、n) within the frequency range 100 to 200 kHz. . Sensitivity within the 100 -to 200 kHz range shall not vary more than3 dB within the temperature range of intended use.A1.1.3 Sensors shall be shielded against electromagnetic interference through proper design practice or differential (anti-coincidenc
21、e) element design, or both.A1.1.4 Sensors shall be electrically isolated from conductive surfaces.A1.1.5 Sensors shall have omni-directional response, with variations not exceeding 2 dB from the peak response.A1.2 Sensor-Preamplifier CableA1.2.1 Cable connecting sensor to preamplifier shall not atte
22、nuate the sensor peak voltage in the 100 to 200 kHz frequency rangemore than 3 dB (2 m 6 ft is a typical length). Integral preamplifier sensors meet this requirement. They have inherently short,internal, signal cables.A1.2.2 Sensor-preamplifier cable shall be shielded against electromagnetic interfe
23、rence. Standard low-noise coaxial cable isgenerally adequate.A1.3 CouplantA1.3.1 Commercially available couplants for ultrasonic flaw detection may be used. Silicone-based stopcock grease has beenfound to be particularly suitable. Quick-setting adhesives may be used, provided the reduced couplant se
24、nsitivity is accounted forby closer sensor spacing. Couplant selection should be made to minimize changes in coupling sensitivity during an examination.Consideration should be given to the time duration of the examination and to the surface temperature of the tank.E1930/E1930M 1710A1.4 PreamplifierA
25、1.4.1 Preamplifier shall have noise level no greater than 5 microvolts rms (referred to a shorted input) within the 100 to 200 kHzfrequency range.A1.4.2 Preamplifier gain shall vary no more than 6 1 dB within the 100 to 200 kHz frequency band and temperature range ofuse.A1.4.3 Preamplifier shall be
26、shielded from electromagnetic interference.A1.4.4 Preamplifiers of differential design shall have a minimum of 40 dB common-mode rejection.A1.4.5 Preamplifier shall include a bandpass filter with a minimum of 18 dB/octave signal attenuation below the 100 kHz and 18dB/octave above 200 kHz. Note that
27、the crystal resonant characteristics provide additional filtering as does the band pass filter inthe signal conditioner.A1.4.6 It is preferred that the preamplifier be mounted inside the sensor housing.A1.5 Power-Signal CableA1.5.1 Cable and connectors that provide power to preamplifiers, and that c
28、onduct amplified signals to the main processor, shallbe shielded against electromagnetic interference. Signal loss shall be less than 3 dB over the length of the cable. (When standardcoaxial cable is used, 300 m 1000 ft is the maximum recommended cable length to avoid excessive signal attenuation).A
29、1.6 Power SupplyA1.6.1 A stable, grounded, power supply that meets signal processor manufacturers specification shall be used.A1.7 Signal ProcessorA1.7.1 Electronic circuitry gain shall be stable within 61 dB in the temperature range (4C40C) 40F100F.A1.7.2 Threshold shall be accurate within 61 dB.A1
30、.7.3 Signal strength shall be measured on a per channel basis and shall have a resolution of 1 % of the value obtained from aone millisecond duration, 150 kHz sine burst having an amplitude 25 dB above the data analysis threshold. Usable dynamic rangeshall be a minimum of 35 dB.A1.7.4 Peak amplitude
31、 shall have a usable dynamic range of a minimum of 60 dB with 1 dB resolution over the frequency bandof 100 kHz to 200 kHz, and the temperature range of 4C40C 40F100F. Not more than 62 dB variation in peak detectionaccuracy shall be allowed over the stated temperature range. Amplitude values shall b
32、e stated in dB, and must be referenced toa fixed gain output of the system (sensor or preamplifier).A1.7.5 Hit duration shall be accurate to 610 s and is measured from the first threshold crossing to the last threshold crossingof the signal or envelope of the rectified linear voltage time signal. It
33、 shall not include the hit definition time that defines the endof an event.A1.7.6 Arrival TimeHit arrival time shall be recorded globally, for each channel accurate to within one millisecond when a zonelocation technique is used.A1.7.7 Rearm TimeThe rearm time of each channel of the system shall be
34、no greater than 200 s.E1930/E1930M 1711A1.7.8 Hit Definition TimeThe hit definition time shall be 400 s.APPENDIXES(Nonmandatory Information)X1. SENSOR LOCATION GUIDELINESX1.1 General Acommon approach is used to select sensor locations regardless of the size or shape of the tanks examined. Thefirst s
35、tep is to determine the maximum distance between sensors using the techniques described in 10.8.5. Once the maximumspacing has been determined, sensors can be spaced accordingly in rings around the circumference of the tank shell. The first ringwill generally start at or near the bottom of the shell
36、.Additional rings will be added up the sidewall. The vertical distance betweenrings should also be determined on the basis of 10.8.5. The following guidelines should also be considered:X1.1.1 Sensor positions in alternate rings should be staggered. A staggered arrangement provides maximum coverage o
37、f the shellplate sections and is particularly helpful in minimizing the number of AE channels necessary to cover very large tanks.X1.1.2 When possible, additional sensors should be placed near large diameter openings such as manways. When reinforcing padsare present and a zone location technique is
38、used, it is advisable to tee at least two sensors together, placing one on the pad andone on the opposite side of the manway on the tank shell.X1.1.3 For vented storage tanks which cannot fill up into the roof and are not otherwise pressurized above the liquid, it may notbe necessary to place sensor
39、s on the roof. AE will not detect defects in locations which are not stressed during the course of theexamination. Flat roofs on non-pressurized storage tanks normally will not be stressed during AE examination.X2. EXAMPLE INSTRUMENT SETTINGS AND REJECTION CRITERIAX2.1 Acceptance Criteria:X2.1.1 Sig
40、nal strengths (that is, of signals from AE sources) shall not increase with increasing load.X2.1.2 Activity shall not increase with increasing load.X2.1.3 Evaluation Threshold shall be 50 dB (where 0 dB equals one microvolt at the preamplifier input).X2.1.4 Any flaw which is detected must be precise
41、ly located; and, flaw dimensions must be determined using secondary NDTmethod (for example, ultrasonic inspection).X2.1.5 Flaws that are large enough to be “fracture critical flaws”, or that are large enough to grow to fracture critical size beforeanother re-examination is performed, shall cause a t
42、ank to be repaired or removed from service.X2.1.5.1 “Fracture critical” flaw dimensions are based upon fracture mechanics analysis of a vessel using strength propertieswhich correspond to materials of construction.X2.2 Material of ConstructionThis example is based on tanks made from carbon steel.X2.
43、3 Instrumentation, Characteristics and Settings:E1930/E1930M 1712TABLE X2.1Sensor sensitivity -77 dB ref. 1 volt/microbar 1 volt/14.5microPSI at approximately 150 kHzCouplant silicone greasePreamplifier gain 40 dBPreamplifier filter 100 to 300 kHz bandpassPower/signal cable length less than 150 m 50
44、0 ftSignal processor threshold 40 dB (0 dB = 1 v, preamplifier input)Signal processor filter 100 to 300 kHz bandpassHit definition time 400 sBackground noise less than 27 dB (0 dB = 1 v, at thepreamplifier input)Functional check amplitude greater than 80 dB (0 dB = 1v, preamp input)X3. EXAMINATION R
45、EPORTE1930/E1930M 1713SUMMARY OF CHANGESCommittee E07 has identified the location of selected changes to this standard since the last issue(E1930 - 07E1930 - 12) that may impact the use of this standard. (June 15, 2012)1, 2017)(1) Changed designation to be aAdded ISO 9712 to section 2 combined units
46、and subsection 6.2.1standard. in accordance withPolicy P10.(2) Changed subsectionEdited A1.1.2 1.12 to be a combined units standard.to add two moreASTM documents,Test Method E1106and Practice E1781, which fills the gap after removal of the sensor sensitivity line in Table X2.1, removed because it wa
47、scontentious.(3) Changed values in the standard to the format of a combined units standard. Format changes were made in subsections: 7.3, 7.4,9.3.2, 9.4,10.5, 10.8.5, 10.8.7, Note 4 (C, D, and E), A1.2.1, A1.5.1, A1.7.1, A1.7.4, X2.3.FIG. X3.1 Sample Examination ReportE1930/E1930M 1714(4) Changes we
48、re made to modernize electronic equipment terms and descriptions in paragraphs 7.7 and 7.8.(5) Corrected mixup in use of standardization versus calibration in Section 9 and subsection 9.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with an
49、y item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquar
