Standard Practice for In Situ Electromagnetic (Eddy-Current) Examination of Nonmagnetic Heat Exchanger Tubes

SIGNIFICANCE AND USE
Eddy-current examination is a nondestructive method of locating discontinuities in tubing made of materials that conduct electricity. Signals can be produced by discontinuities located either on the inner or outer surfaces of the tube, or by discontinuities totally contained within the tube wall. When using an internal probe, the density of eddy currents in the tube wall decreases very rapidly as the distance from the internal surface increases; thus the amplitude of the response to outer surface discontinuities decreases correspondingly.
Some indications obtained by this method may not be relevant to product quality. For example, an irrelevant signal may be caused by metallurgical or mechanical variations that are generated during manufacture but that are not detrimental to the end use of the product. Irrelevant indications can mask unacceptable discontinuities occurring in the same area. Relevant indications are those that result from nonacceptable discontinuities. Any indication above the reject level, which is believed to be irrelevant, shall be regarded as unacceptable until it is proven to be irrelevant. For tubing installed in heat exchangers, predictable sources of irrelevant indications are lands (short unfinned sections in finned tubing), dents, scratches, tool chatter marks, or variations in cold work. Rolling tubes into the supports may also cause irrelevant indications, as may the tube supports themselves. Eddy-current examination systems are generally not able to separate the indication generated by the end of the tube from indications of discontinuities adjacent to the ends of the tube (end effect). Therefore, this examination may not be valid at the boundaries of the tube sheets.
SCOPE
1.1 This practice describes procedures to be followed during eddy-current examination (using an internal, probe-type, coil assembly) of nonmagnetic tubing that has been installed in a heat exchanger. The procedure recognizes both the unique problems of implementing an eddy-current examination of installed tubing, and the indigenous forms of tube-wall deterioration which may occur during this type of service. The document primarily addresses scheduled maintenance inspection of heat exchangers, but can also be used by manufacturers of heat exchangers, either to examine the condition of the tubes after installation, or to establish baseline data for evaluating subsequent performance of the product after exposure to various environmental conditions. The ultimate purpose is the detection and evaluation of particular types of tube integrity degradation which could result in in-service tube failures.
1.2 This practice does not establish acceptance criteria; they must be specified by the using parties.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E690 − 10
StandardPractice for
In Situ Electromagnetic (Eddy-Current) Examination of
1
Nonmagnetic Heat Exchanger Tubes
This standard is issued under the fixed designation E690; 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* 2.2 Other Documents:
SNT-TC-1A Recommended Practice for Personnel Qualifi-
1.1 Thispracticedescribesprocedurestobefollowedduring
3
cation and Certification in Nondestructive Testing
eddy-current examination (using an internal, probe-type, coil
ANSI/ASNT-CP-189 ASNT Standard for Qualification and
assembly) of nonmagnetic tubing that has been installed in a
3
Certification of Nondestructive Testing Personnel
heat exchanger. The procedure recognizes both the unique
NAS-410 NAS Certification and Qualification of Nonde-
problems of implementing an eddy-current examination of
4
structive Personnel (Quality Assurance Committee)
installed tubing, and the indigenous forms of tube-wall dete-
rioration which may occur during this type of service. The
3. Terminology
document primarily addresses scheduled maintenance inspec-
3.1 Standard terminology relating to electromagnetic ex-
tion of heat exchangers, but can also be used by manufacturers
amination may be found in Terminology E1316, Section C,
of heat exchangers, either to examine the condition of the tubes
Electromagnetic Testing.
after installation, or to establish baseline data for evaluating
subsequent performance of the product after exposure to
4. Summary of Practice
various environmental conditions. The ultimate purpose is the
4.1 The examination is performed by passing an eddy-
detection and evaluation of particular types of tube integrity
current probe through each tube. These probes are energized
degradation which could result in in-service tube failures.
with alternating currents at one or more frequencies. The
1.2 This practice does not establish acceptance criteria; they
electrical impedance of the probe is modified by the proximity
must be specified by the using parties.
of the tube, the tube dimensions, electrical conductivity,
1.3 This standard does not purport to address all of the
magnetic permeability, and metallurgical or mechanical dis-
safety concerns, if any, associated with its use. It is the continuities in the tube. During passage through the tube,
responsibility of the user of this standard to establish appro-
changes in electromagnetic response caused by these variables
priate safety and health practices and determine the applica- in the tube produce electrical signals which are processed so as
bility of regulatory limitations prior to use.
to produce an appropriate combination of visual displays,
alarms, or temporary or permanent records, or combination
2. Referenced Documents
thereof, for subsequent analysis.
2
2.1 ASTM Standards:
5. Significance and Use
E543 Specification for Agencies Performing Nondestructive
5.1 Eddy-current examination is a nondestructive method of
Testing
E1316 Terminology for Nondestructive Examinations locating discontinuities in tubing made of materials that
conduct electricity. Signals can be produced by discontinuities
located either on the inner or outer surfaces of the tube, or by
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
discontinuities totally contained within the tube wall. When
structive Testing and is the direct responsibility of Subcommittee E07.07 on
using an internal probe, the density of eddy currents in the tube
Electromagnetic Method.
CurrenteditionapprovedJune1,2010.PublishedJuly2010.Originallyapproved
wall decreases very rapidly as the distance from the internal
´1
in 1979. Last previous edition approved in 1998 as E690 – 98(2004) . DOI:
10.1520/E0690-10.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
4
Standards volume information, refer to the standard’s Document Summary page on Available fromAerospace IndustriesAssociation ofAmerica, Inc. (AIA), 1000
the ASTM website. WilsonBlvd.,Suite1700,Arlington,VA22209-3928,http://www.aia-aerospace.org.
*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. United States
1

---------------------- Page: 1 ----------------------
E690 − 10
surface increases; thus the amplitude of the response to outer practice or standard used an
...

This document 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation:E690–98 (Reapproved 2004) Designation: E690 – 10
Standard Practice for
In Situ Electromagnetic (Eddy-Current) Examination of
1
Nonmagnetic Heat Exchanger Tubes
This standard is issued under the fixed designation E690; 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
´ NOTE—Editorial changes made throughout in January 2004.
1. Scope*
1.1 This practice describes procedures to be followed during eddy-current examination (using an internal, probe-type, coil
assembly) of nonmagnetic tubing that has been installed in a heat exchanger. The procedure recognizes both the unique problems
of implementing an eddy-current examination of installed tubing, and the indigenous forms of tube-wall deterioration which may
occur during this type of service.The document primarily addresses scheduled maintenance inspection of heat exchangers, but can
also be used by manufacturers of heat exchangers, either to examine the condition of the tubes after installation, or to establish
baseline data for evaluating subsequent performance of the product after exposure to various environmental conditions. The
ultimate purpose is the detection and evaluation of particular types of tube integrity degradation which could result in in-service
tube failures.
1.2 This practice does not establish acceptance criteria; they must be specified by the using parties.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E543 Specification for Agencies Performing Nondestructive Testing
E1316 Terminology for Nondestructive Examinations
2.2 Other Documents:
3
SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
3
ANSI/ASNT-CP-189 ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel
4
NAS-410 NAS Certification and Qualification of Nondestructive Personnel (Quality Assurance Committee)
3. Terminology
3.1 Standard terminology relating to electromagnetic examination may be found in Terminology E1316, Section C,
Electromagnetic Testing.
4. Summary of Practice
4.1 The examination is performed by passing an eddy-current probe through each tube. These probes are energized with
alternating currents at one or more frequencies. The electrical impedance of the probe is modified by the proximity of the tube,
the tube dimensions, electrical conductivity, magnetic permeability, and metallurgical or mechanical discontinuities in the tube.
During passage through the tube, changes in electromagnetic response caused by these variables in the tube produce electrical
signals which are processed so as to produce an appropriate combination of visual displays, alarms, or temporary or permanent
1
This practice is under the jurisdiction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.07 on Electromagnetic
Methods.
Current edition approved January 1, 2004. Published February 2004. Originally approved in 1979. Last previous edition approved in 1998 as E690–98. DOI:
10.1520/E0690-98R04E01.on Electromagnetic Method.
´1
Current edition approved June 1, 2010. Published July 2010. Originally approved in 1979. Last previous edition approved in 1998 as E690 – 98(2004) . DOI:
10.1520/E0690-10.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book ofASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from The American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
4
Available from Aerospace Industries Association of America, Inc., 1250 Eye Street, N.W., Washington, DC 20005.
4
Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http://www.aia-aerospace.org.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
...

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