1、Designation:E193007 Designation: E1930/E1930M 12Standard 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 y
2、earof 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 emissio
3、n (AE) 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 s
4、idewalls (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 no
5、rmalcontents 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 ta
6、nks made 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 confir
7、m the 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 pr
8、essure.1.11 Leaks may be found during the course of this examination but their detection is not the intention of this practice.1.12The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are forinformation only.1.12 UnitsThe values stated in either
9、 SI units or inch-pound units are to be regarded as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system 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 n
10、ot purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are gi
11、ven in Section 8.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestructive TestingE650 Guide for Mounting Piezoelectric Acoustic Emission SensorsE976 Guide for Determining the Reproducibility of Acoustic Emission Sensor ResponseE1316 Terminology for Nondest
12、ructive ExaminationsE2374 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/ASNT CP-189 Standard for Qualification and Certification of NDT Personnel31This
13、 practice is under the jurisdiction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic EmissionMethod.Current edition approved Dec. 1, 2007. Published December 2007. Originally approved in 1997. Last previous edition approved in 2002 as
14、E1930-02. DOI:10.1520/E1930-07.Current edition approved June 15, 2012. Published July 2012. Originally approved in 1997. Last previous edition approved in 2007 as E1930 - 07. DOI:10.1520/E1930_E1930M-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Se
15、rvice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.1This do
16、cument is not an ASTM standard 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 a
17、s appropriate. In all cases only 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 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Uni
18、ted States.2.3 ASME Standard:Section V, Article 12, Boiler metal storage tanks; above ground storage tanksANNEX(Mandatory Information)FIG. 3 In Service Tank Fill ScheduleE1930/E1930M 129A1. SPECIFICATIONS FOR APPARATUSA1.1 Instrumentation SpecificationsA1.1.1 AE sensors shall be resonant in a 100 to
19、 200 kHz frequency band.A1.1.2 Sensors shall have a peak sensitivity greater than -77 dB (referred to 1 volt per microbar, determined by face-to-faceultrasonic examination) within the frequency range 100 to 200 kHz. Sensitivity within the 100 - 200 kHz range shall not vary morethan 3 dB within the t
20、emperature range of intended use.A1.1.3 Sensors shall be shielded against electromagnetic interference through proper design practice or differential (anti-coincidence) element design, or both.A1.1.4 Sensors shall be electrically isolated from conductive surfaces.A1.1.5 Sensors shall have omni-direc
21、tional 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 attenuate the sensor peak voltage in the 100 to 200 kHz frequencyrange more than 3 dB (6 ft (1.83 m)(2 m 6 ft is a typical length). Integr
22、al preamplifier sensors meet this requirement. They haveinherently short, internal, signal cables.A1.2.2 Sensor-preamplifier cable shall be shielded against electromagnetic interference. Standard low-noise coaxial cable isgenerally adequate.A1.3 CouplantA1.3.1 Commercially available couplants for ul
23、trasonic 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 sensitivity is accounted forby closer sensor spacing. Couplant selection should be made to minimize changes in coupling se
24、nsitivity during an examination.Consideration should be given to the time duration of the examination and to the surface temperature of the tank.A1.4 PreamplifierA1.4.1 Preamplifier shall have noise level no greater than 5 microvolts rms (referred to a shorted input) within the 100 to 200kHz frequen
25、cy 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 shielded from electromagnetic interference.A1.4.4 Preamplifiers of differential design shall have a minimum of 40 dB common-mode rejectio
26、n.A1.4.5 Preamplifier shall include a bandpass filter with a minimum of 18 dB/octave signal attenuation below the 100 kHz and18 dB/octave above 200 kHz. Note that the crystal resonant characteristics provide additional filtering as does the band pass filterin the signal conditioner.A1.4.6 It is pref
27、erred 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 conduct amplified signals to the main processor, shallbe shielded against electromagnetic interference. Signal loss shall be less than 3 d
28、B 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).A1.6 Power SupplyA1.6.1 A stable, grounded, power supply that meets signal processor manufacturers specification shall be used.A1.7 Signal
29、 ProcessorA1.7.1Electronic circuitry gain shall be stable within 61 dB in the temperature range 40 to 100F (4.4 to 37.8C).A1.7.1 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.A1.7.3 Signal strength shal
30、l be measured on a per channel basis and shall have a resolution of 1 % of the value obtained froma one 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 shall have a usable dyna
31、mic 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 40 to 100F (4 to 52C).4C40C 40F100F. Not more than 62dBvariation in peak detection accuracy shall be allowed over the stated temperature range. Amplitude values shall be st
32、ated in dB,and must be referenced to a 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 sha
33、ll not include the hit definition time that defines the endof an event.E1930/E1930M 1210A1.7.6 Arrival TimeHit arrival time shall be recorded globally, for each channel accurate to within one millisecond when azone location technique is used.A1.7.7 Rearm TimeThe rearm time of each channel of the sys
34、tem shall be no greater than 200 s.A1.7.8 Hit Definition TimeThe hit definition time shall be 400 s.APPENDIXES(Nonmandatory Information)X1. SENSOR LOCATION GUIDELINESX1.1 General A common approach is used to select sensor locations regardless of the size or shape of the tanks examined.The first step
35、 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. A
36、dditional 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 of
37、theshell plate 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 reinforcingpads are present and a zone location technique is us
38、ed, it is advisable to tee at least two sensors together, placing one on the padand one 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 maynot be necessary to place sensors
39、on the roof. AE will not detect defects in locations which are not stressed during the course ofthe examination. 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 Signa
40、l 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 precisely
41、 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 tan
42、k 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.X2.3
43、Instrumentation, Characteristics and Settings:Sensor sensitivity -77 dB ref. 1 volt/microbar at approxi-mately 150 kHzSensor 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 bandpassP
44、ower/signal cable length less than 500 ft (152 m)Power/signal cable length less than 150 m 500 ftSignal processor threshold 40 dB (0 dB=1v,preamplifier input)Signal processor filter 100 to 300 kHz bandpassHit definition time 400 sBackground noise less than 27 dB (0 dB=1v,atthepreamplifier input)Func
45、tional check amplitude greater than 80 dB (0 dB = 1v, preamp input)X3. EXAMINATION REPORTSUMMARY OF CHANGESCommittee E07 has identified the location of selected changes to this standard since the last issue (E1930 - 07)that may impact the use of this standard. (June 15, 2012)E1930/E1930M 1211(1) Cha
46、nged designation to be a combined units standard.(2) Changed subsection 1.12 to be a combined units standard.(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,
47、 A1.5.1, A1.7.1, A1.7.4, X2.3.(4) Changes were 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
48、patent rights asserted in connection with any 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 revis
49、ion 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 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Stand
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