ASTM E2929-18(2022)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2929 − 18 (Reapproved 2022)
Standard Practice for
Guided Wave Testing of Above Ground Steel Piping with
Magnetostrictive Transduction
This standard is issued under the fixed designation E2929; the number immediately following the designation indicates the year of
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 obtained is complex and training is required to properly
perform data interpretation.
1.1 This practice provides a guide for the use of waves
generated using magnetostrictive transduction for guided wave 1.7 This practice does not establish an acceptance criterion.
testing (GWT) welded tubulars. Magnetostrictive materials Specific acceptance criteria shall be specified in the contractual
transduce or convert time varying magnetic fields into me- agreement by the cognizant engineer.
chanical energy.As a magnetostrictive material is magnetized,
1.8 Units—The values stated in SI units are to be regarded
it strains. Conversely, if an external force produces a strain in
as standard. The values given in parentheses are mathematical
a magnetostrictive material, the material’s magnetic state will
conversions to SI units that are provided for information only
change. This bi-directional coupling between the magnetic and
and are not considered standard.
mechanical states of a magnetostrictive material provides a
1.9 This standard does not purport to address all of the
transduction capability that can be used for both actuation and
safety concerns, if any, associated with its use. It is the
sensing devices.
responsibility of the user of this standard to establish appro-
1.2 GWT utilizes ultrasonic guided waves in the 10 to
priate safety, health, and environmental practices and deter-
approximately 250 kHz range, sent in the axial direction of the
mine the applicability of regulatory limitations prior to use.
pipe, to non-destructively test pipes for discontinuities or other
1.10 This international standard was developed in accor-
featuresbydetectingchangesinthecross-sectionorstiffnessof
dance with internationally recognized principles on standard-
the pipe, or both.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 GWT is a screening tool. The method does not provide
mendations issued by the World Trade Organization Technical
adirectmeasurementofwallthicknessortheexactdimensions
Barriers to Trade (TBT) Committee.
of discontinuities. However, an estimate of the severity of the
discontinuity can be obtained.
2. Referenced Documents
1.4 This practice is intended for use with tubular carbon
2.1 ASTM Standards:
steel products having nominal pipe size (NPS) 2 to 48
E543 Specification forAgencies Performing Nondestructive
corresponding to 60.3 to 1219.2 mm (2.375 to 48 in.) outer
Testing
diameter, and wall thickness between 3.81 and 25.4 mm (0.15
E1316 Terminology for Nondestructive Examinations
and 1 in.).
IEEE/SI-10 American National Standard for Metric Practice
1.5 This practice only applies to GWT of basic pipe
2.2 Other Standards:
configuration. This includes pipes that are straight, constructed
SNT-TC-1A Personnel Qualification and Certification in
of a single pipe size and schedules, fully accessible at the test
Non-Destructive Testing
location, jointed by girth welds, supported by simple contact
supports and free of internal, or external coatings, or both; the
3. Terminology
pipe may be insulated or painted.
3.1 Definitions of terms specific to this standard are pro-
1.6 This practice provides a general practice for performing
vided in this section. Some common terms such as defect may
the examination. The interpretation of the guided wave data
be referenced to Terminology E1316.
1 2
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
structive Testing and is the direct responsibility of Subcommittee E07.10 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Specialized NDT Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2022. Published December 2022. Originally the ASTM website.
approved in 2013. Last previous edition approved in 2018 as E2929 – 18. DOI: AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
10.1520/E2929-18R22. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2929 − 18 (2022)
3.2 Definitions of Terms Specific to This Standard: 3.2.17 time controlled gain (TCG)—gain applied to the
signal as a function of time or distance from the initial pulse
3.2.1 circumferential extent—thelengthofadiscontinuityin
used to compensate wave attenuation in the pipeline. The TCG
the circumferential direction, usually given as a percentage of
normalizes the amplitude over the entire time scale displayed.
the pipe circumference.
Forexample,usingTCG,a5 %reflectornearthe probehasthe
3.2.2 circumferential orientation—the circumferential posi-
sameamplitudeasa5 %reflectorattheendofthetimedisplay.
tion of a localized indication on the pipe, usually given as the
The TCG plot can be used in lieu of DAC curve plot.
clock position or degrees from the top circumferential position
3.2.18 torsional wave—wave propagation mode that pro-
of the pipe.
duces twisting motion in the pipe.
3.2.3 coherent noise—indications caused by real disconti-
3.2.19 transduction device—a device used to produce and
nuities causing a background noise, which exponentially de-
detect guided waves. It is commonly called “guided wave
cays with distance (see Terminology E1316).
probe.”
3.2.4 cross-sectional area change (CSC)—the change in the
3.2.20 wave mode—a particular form of propagating wave
circumferential cross-section of pipe from its nominal total
motion generated into a pipe, such as flexural, torsional or
cross-section, usually given in percentage.
longitudinal.
3.2.5 dead zone—this is an area that can be up to1m(3ft)
4. Summary of Practice
long on either side of the transducer ring that is not inspected
duringthetesting.Theareaofthedeadzoneisafunctionofthe
4.1 GWTevaluatestheconditionofmetalpipestoprimarily
excitationfrequencyandthenumberofcyclestransmitted.The
establish the severity classification of defects by applying GW
area is inversely related to frequency and directly related to the
over a typical test frequency range from 10 to approximately
number of cycles.
250 kHz which travels along the pipe. Reflections are gener-
ated by the change in cross-sectional area or local stiffness of
3.2.6 estimated cross-sectional loss (ECL)—this is some-
the pipe, or both.
times used instead of Cross-SectionalArea Change, where the
feature is related to a defect.
4.2 The transduction device attached around the pipe gen-
erates guided waves that travel in the pipe wall. The direction
3.2.7 flexural wave—wave propagation mode that produces
of wave propagation is controlled or can be in both directions
bending motion in the pipe.
simultaneously. These guided waves can evaluate long lengths
3.2.8 guided wave (GW)—stress waves travelling in a struc-
of pipe and are especially useful when access to the pipe is
ture bounded in the geometry and configuration of the struc-
limited.
ture.
4.3 This examination locates areas of thickness reduction(s)
3.2.9 guided wave testing (GWT)—non-destructive test
and provides a severity classification as to the extent of that
method that utilizes guided waves.
damage. The results are used to assess the condition of the
pipe, to determine where damaged areas are located along the
3.2.10 incoherent noise—random signals caused by electri-
length of the pipe, and their circumferential position on the
cal and ambient radio frequency signal pollution, giving rise to
pipe (when segmented transmitters or receivers, or both, are
a constant average noise floor.The terms “Ambient Noise” and
used). The information can be used to program and prioritize
“Random Noise” are also used.
additional inspection work and repairs.
3.2.11 pipe feature—pipe components including but not
4.4 Reflections produced by pipe features (such as circum-
limited to weld, support, flange, bend, and flaw (defect) cause
ferential welds, elbows, welded supports, vents, drainage,
reflections of a guided wave due to a change in geometry.
insulation lugs, and other welded attachments) and that are not
3.2.12 reflection amplitude—the amplitude of the reflection
associated with areas containing possible defects are consid-
signal typically reported as CSC or reflection coefficient.
ered as relevant signals and can be used for setting GWsystem
3.2.13 reflection coeffıcient—a parameter that represents the
defect detection sensitivity levels and time calibration.
amplitudeofreflectedsignalfromapipefeaturewithrespectto
4.5 Other sources of reflection may include changes in
the incident wave amplitude, usually expressed in percentage
surface impedance of the pipe (such as pipe supports and
and called “% reflection.” Used in lieu of CSC to characterize
clamps). These reflections are normally not relevant, but
the severity of indications.
should be analyzed and classified in an interpretation process.
3.2.14 shear wave couplant—couplant designed specifically
In the advanced applications which are not covered by this
toeffectivelycoupledirectlygeneratedshearwaves(wavesnot
practice, these changes may also include various types of
generated through refraction of longitudinal waves).
external/internal coatings, entrance of the pipe to ground, or
concrete wall.
3.2.15 signal to noise ratio (SNR)—ratiooftheamplitudeof
any signal of interest to the amplitude of the average back- 4.6 Inspectionofthepipesectionimmediatelyconnectingto
ground noise which includes both coherent and non-coherent
branch connections, bends or flanges are considered advance
types of noise. applications which are not covered by this practice.
3.2.16 test location—location where the transduction device 4.7 False indications are produced by phenomena such as
is placed on the pipe for inspection. reverberations, incomplete control of wave propagation
E2929 − 18 (2022)
direction,distortionatelbows,andothers.Thesesignalsshould 6.3 Thispracticeorstandardusedanditsapplicablerevision
be analyzed and classified as false echoes in the interpretation shall be identified in the contractual agreement between the
process. using parties.
6.4 Qualifications of Non-destructive Testing Agencies—
5. Significance and Use
Unless otherwise specified in the contractual agreement, NDT
5.1 The purpose of this practice is to outline a procedure for agencies shall be qualified and evaluated as described in
Specification E543, and the applicable edition of Specification
using GWT to locate areas in metal pipes in which wall loss
has occurred due to corrosion or erosion. E543 shall be specified in the contractual agreement.
6.5 Procedure and Techniques—The procedures and tech-
5.2 GWT does not provide a direct measurement of wall
thickness, but is sensitive to a combination of the CSC (or niques to be utilized shall be specified in the contractual
agreement.Itshouldincludethescopeoftheinspection,thatis,
reflection coeffıcient) and circumferential extent and axial
extent of any metal loss. Based on this information, a classi- the overall NDT examination intended to identify and estimate
the size of any indications detected by the examination, or
fication of the severity can be assigned.
simply locate and provide a relative severity classification.
5.3 The GWT method provides a screening tool to quickly
6.6 Surface Preparation—The pre-examination site prepa-
identify any discontinuity along the pipe. Where a possible
ration criteria shall be in accordance with 8.3 unless otherwise
defect is found, a follow-up inspection of suspected areas with
specified.
ultrasonic testing or other NDT methods is normally required
to obtain detailed thickness information, nature, and extent of
6.7 Required Interval of Examination—The required inter-
damage.
val or the system time in service of the examination shall be
specified in the contractual agreement.
5.4 GWT also provides some information on the axial
length of a discontinuity, provided that the axial length is
6.8 Extent of the Examination—The extent of the examina-
longer than roughly a quarter of the wavelength.
tion shall be in accordance with 6.5 above unless otherwise
specified. The extent should include but is not limited to:
5.5 The identification and severity assessment of any pos-
6.8.1 The sizes and length(s) of pipes to be inspected.
sible defects is qualitative only. An interpretation process to
6.8.2 Limitations of the method in the areas of application.
differentiate between relevant and non-relevant signals is
6.8.3 Drawings of pipe circuits, pipe nomenclature and
necessary.
identification of examination locations.
5.6 This practice only covers the application specified in the
6.8.4 Pipe access method(s).
scope.TheGWTmethodhasthecapabilityandcanbeusedfor
6.8.5 Safety requirements.
applications where the pipe is insulated, buried, in road
6.9 Reporting Criteria—The test results of the examination
crossings, and where access is limited.
shall be documented in accordance with the contractual agree-
5.7 GWT shall be performed by qualified and certified
ment. This may include requirements for permanent records of
personnel, as specified in the contract or purchase order.
the collected data and test reports. The report documentation
Qualifications shall include training specific to the use of the
should include:
equipment employed, interpretation of the test results, and
6.9.1 Equipment inspector and test results reviewed by (if
guided wave technology.
applicable).
5.8 A documented program which includes training,
6.9.2 Date and time of the examination performed.
examination, and experience for the GWT personnel certifica-
6.9.3 Equipment used.
tion shall be maintained by the supplying party.
6.9.4 Test procedure/specification used.
6.9.5 Acceptance criteria.
6. Basis of Application 6.9.6 Inspection location.
6.9.7 Identification of areas inspected.
6.1 The following items are subject to contractual agree-
6.9.8 Identification of the inspection range.
ment between the parties using or referencing this practice.
6.9.9 Any other information deemed necessary to reproduce
6.2 Personnel Qualifications—Unlessotherwisespecifiedin
or duplicate test results.
the contractual agreement, personnel performing examinations
6.10 Reexamination of Repairs/Rework Items—
to this practice shall be qualified in accordance with one of the
Examination of repaired/reworked items is not addressed in
following:
this practice and, if required, shall be specified in the contrac-
6.2.1 Personnel performing examinations to this practice
tual agreement.
shall be qualified in accordance with SNT-TC-1A and certified
by the employer or certifying agency, as applicable. Other
7. Apparatus
equivalent qualification documents may be used when speci-
fied in the contract or purchase order. The applicable revision 7.1 The GWT apparatus shall include the following:
shall be the latest unless otherwise specified in the contractual
7.1.1 Transduction Device Transmitter—Atransductionsys-
agreement between parties. tem using the magnetostrictive effect for the generation of
6.2.2 Personnel qualification accredited by the GWT equip- guided wave modes with axial propagation on cylindrical
ment manufacturers. pipes.
E2929 − 18 (2022)
7.1.2 Transduction Device Receiver—A system for the de- evaluation sections of pipe immediately after elbows. In any
tection of the signal reflected by the geometric features on the case, no signals after two elbows should be analyzed. It is
pipe, which can be the same as the transmitter or an analogous sometimes better to take additional data at different locations
transduction system. than interpreting a signal beyond multiple features or those
7.1.3 Instrumentation—The GWT instrumentation shall be withcomplicatedgeometries.Considertakingasecondreading
capable of generating, receiving and amplifying electrical at a second test location (as recommended by the manufac-
pulses within the frequency range used by GWT.Additionally, turer) for confirmation of features and false echo identification.
it shall be capable of communicating with a computer so that 8.3.4 Visual Inspection—Visually inspect the pipe where
collected data can be processed and recorded. possible for potential damage areas or corrosion, such as the
7.1.4 Processing System—This is a software interface for support areas, if possible defect indications are found in the
processing and analyzing the signal, capable of distinguishing GWT result.
at least one guided wave mode for the specific detection 8.3.5 Surface Temperature—Verifythatthesurfacetempera-
system. ture of the pipe to be tested is within the manufacturer’s
specifications for the equipment.
8. Examination Procedure
8.3.6 Thickness Check—Before mounting the transduction
device, verify that there is no degradation in the pipe wall
8.1 It is important to ensure that the proposed inspection
thickness at the test location. As a minimum requirement,
falls within the capabilities of the technology and equipment
thickness measurements at no less than four equally spaced
and that the using party or parties understand the capabilities
positions around the pipe should be made using an appropriate
and limitations as it applies to their inspection.
thickness measuring instrument and procedure. Some agencies
8.2 Pre-examination Preparation:
may also require thickness measurement of the entire dead
8.2.1 All test equipment shall have current and valid cali-
zone. It is important to note that attaching the transduction
bration certificates.
device at locations with very severe corrosion may cause
8.2.2 Follow the equipment manufacturer’s recommenda-
further damage to the pipe if a mechanical force system is used
tions with regard to equipment pre-test verification and check
for coupling.
list. As a minimum this check list should include but is not
8.4 Transduction Device—The transduction device should
limited to:
be attached to the pipe using proper coupling methods.
8.2.2.1 Electronics fully operational.
8.2.2.2 Verification that interconnection cables are in good
8.5 Couplant—Good coupling is obtained by simply apply-
condition and functioning correctly.
ingsufficientmechanicalforceonthetransductiondeviceorby
8.2.2.3 Correct transduction device size for the intended
the use of epoxy bonding or shear wave couplant on the
pipes.
transduction device in lieu of mechanical force devices.
8.2.2.4 The transduction device is functioning correctly.
8.6 Choosing Test Location—After completing the exami-
8.2.2.5 Any computer used with the system is functioning
nation site preparation outlined in 8.3, attach the transduction
correctly and has sufficient storage capacity for the intended
device to the pipe. The test location should be chosen so as to
work scope.
minimize false echoes. Avoid placing the transduction device
8.2.2.6 Supplementary equipment, such as an ultrasonic
near a feature as the corresponding signal may appear within
flaw detector or specialized pit gauges are available and
the dead zone. In the dead zone, no echoes are received, as a
functioning correctly.
practice, a minimum of 0.13 m (0.4 ft) should be used to the
8.2.2.7 All necessary accessories such as tape-measure and
first area of inspection. Features such as welds which are used
markers are available.
for the DAC curves or TCG correction fitting, should be
8.2.3 Ensure all site safety requirements and procedures are
outside the dead zone to ensure valid amplitude. Additionally,
reviewed and understood prior to starting any field work.
transduction devices should not be positioned equidistant
8.3 Examination Site Preparation:
between two features to avoid masking of the mirror echoes, if
8.3.1 Pipe Surface Condition—To obtain the best coupling
any.
condition,thesurfaceshallbecleanandfreeofanyloosepaint,
8.7 Attaching the Transduction Device—Whenattachingthe
dirt, oxidation, or any foreign substance that may interfere in
transduction device, it is important to ensure that the FeCo flat
energy transmission. Wire brushing or sanding, or both, are
strip is in good contact with the pipe and that the transduction
usually sufficient to prepare the surface if it is safe and
device is mounted parallel to the circumference of the pipe.
permitted to do so.
Further, it is important to apply the appropriate air pressure,
8.3.2 Insulation—If the pipe is insulated, carefully remove
clamp torque settings (if dry coupling is used), or bonding or
an amount of insulation for mounting the magnetostrictive
shear wave couplant as specified in the manufacturer’s oper-
transduction device to the pipe (a minimum of 0.3 m (1 ft).
ating manual for proper installation of the transduction device.
Prior to removing the insulating material ensure it is safe and
permissible to do so. 8.8 Directionality and Orientation—The reported direction-
8.3.3 GWTismosteffectivefortestinglonglengthsofpipe. ality and orientation of the features depend on the way the
However, short radius elbows distort GWT signals, making transduction device is installed. It is good practice to keep the
interpretationofsignalsobtainedatdistancesbeyondtheelbow direction between different test locations the same, and in the
difficult. Where possible, it is good practice to exclude from direction of product flow if known. To ensure the correct
E2929 − 18 (2022)
orientationisreported,asegmentedtransductiondeviceshould 8.12.3.1 Reverberations—Multiple reflections either be-
be attached in accordance with the GWT manufacturer’s tween two large features along the pipe, or between the two
recommendations. ends of a long feature. Echoes caused by reverberations
typically have small amplitudes.
8.9 Reproducibility—The examination pipe should be
8.12.3.2 Mirrors—Occurs due to insufficient control of the
marked with a paint marker indicating the transduction device
propagation direction of the guided wave. The mirror echo
position, direction, and date of ex
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