ISO 18211:2016

DRAFT INTERNATIONAL STANDARD ISO/DIS 18211.2
Secretariat: IIW
Voting begins on Voting terminates on

2015-06-29 2015-08-29
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION    МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ    ORGANISATION INTERNATIONALE DE NORMALISATION

Non-destructive testing — Long range inspection of above
ground pipelines and plant piping using guided wave testing
with axial propagation
Titre manque
Partie #: Titre de la partie
ICS 19.100
Member bodies are requested to consult relevant national interests in ISO/TC 44/SC ## before
returning their ballot to the ISO Central Secretariat.

This draft International Standard is submitted to all ISO member bodies for voting, as a
standard prepared by an international standardizing body in accordance with Council
Resolution 42/1999. The proposer, the International Institute of Welding (IIW), has been
recognized by the ISO Council as an international standardizing body for the purpose of
Council Resolution 42/1999.
To expedite distribution, this document is circulated as received from the committee
secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at
publication stage.
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REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
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THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©  International Organization for Standardization, 2015

ISO/DIS 18211.2
©  ISO 2015
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ii © ISO 2015 – All rights reserved

ISO/DIS 18211.2
Contents Page
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test personnel . 3
5 General . 3
6 Factors influencing GWT performance . 4
6.1 External diameter . 4
6.2 Pipeline geometry . 4
6.3 Test range . 4
6.4 Road crossing . 5
7 Test equipment . 5
7.1 General . 5
7.2 Probe ring . 5
7.3 Signal processing and analysis system . 6
7.4 Periodic verification of equipment performance . 6
7.5 Settings . 6
8 Test procedure . 6
9 Requirements for test data quality . 7
10 Testing . 7
10.1 Preparation of the test object . 7
10.1.1 Surface temperature . 7
10.1.2 Removal of insulation . 7
10.1.3 Wall thickness assessment . 8
10.1.4 Surface preparation . 8
10.2 Probe ring test position . 8
10.3 Data Collection . 8
10.4 Reporting sensitivity . 8
10.5 Data interpretation . 9
10.6 Detection sensitivity . 9
10.7 Visual confirmation . 9
11 Complementary NDT to support the GWT . 9
12 Test report . 10
Annex A (informative) Selection of guided wave modes . 11
Bibliography . 15

ISO/DIS 18211.2
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18211 was prepared by IIW, the International Institute of Welding.

iv © ISO 2015 – All rights reserved

DRAFT INTERNATIONAL STANDARD ISO/DIS 18211.2

Non-destructive testing — Long range Inspection of above
ground pipelines and plant piping using guided wave testing
with axial propagation
1 Scope
This International Standard specifies a method for long range testing of carbon and low alloy steel above
ground pipelines and plant piping using guided ultrasonic waves with axial propagation applied on the entire
circumferential pipe section, in order to detect corrosion or erosion damage.
The Guided Wave Testing (GWT) technique allows for fast inspection of above ground pipelines, plant piping
and cased road crossings, giving a qualitative screening and localization of probable corroded and eroded
areas. GWT is typically performed on operating piping systems.
This International Standard can be applied to the following types of pipes:
a) above ground painted pipelines;
b) above ground insulated pipelines;
c) pipe sections within road crossings with external casing (without bitumen or plastic coating);
d) painted plant piping;
e) insulated plant piping.
Other types of pipes not included in the above list need dedicated approaches due to increased complexity.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 9712, Non-destructive testing – Qualification and certification of personnel
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
axial direction
the direction along the main axis of the pipe
3.2
circumferential direction
the direction around the circumference of the pipe
ISO/DIS 18211.2
3.3
total pipe wall cross-section (TCS)
the area between the inner and outer diameters of the pipe in a plane perpendicular to the pipe axis
3.4
cross-section change
the equivalent cross-section change calculated assuming that an indication is purely caused by a change in
the cross-section of the pipe wall
3.5
datum point
reference point for reporting a test position and for correlating test results with the corresponding position on
the test object
3.6
dead zone
length of pipe on either side of the test position where reflectors of interest cannot be detected because they
are covered by the transmitted pulse
3.7
flexural mode
a non-symmetric bending type mode of guided wave propagation in pipes, with particle displacements in axial,
circumferential and radial directions
3.8
focus
concentration of guided waves at a single axial and circumferential position, achieved either by hardware
settings or by post-processing of a recorded set of signals (synthetic focus)
3.9
geometric feature
pipeline feature (i.e. weld, support, flange, bend, etc.) causing the reflection of guided waves because of a
cross section change or other acoustic impedance variation
3.10
guided wave mode
distinct type of guided wave with a specific vibration pattern
3.11
longitudinal mode
a symmetric compression type mode of guided wave propagation in pipes, with particle displacements
predominantly in the axial direction
3.12
primary mode
guided wave mode which is chosen for the incident wave
3.13
probe ring
circumferential component, containing transducer elements with direct contact to the pipe
3.14
secondary mode
guided wave mode which is different from the primary mode and is generated by mode conversion at pipe
features or discontinuities
3.15
test frequency
centre frequency of the pulses transmitted by the probe ring
ISO/DIS 18211.2
3.16
test position
axial position on the pipe where the probe ring is place
3.17
test range
the distance between the test position and the furthest position for which the minimum acceptable sensitivity
of the reference signal is achieved, in each direction (positive or negative)
3.18
torsional mode
a symmetric twisting type mode of guided wave propagation in pipes, with particle displacements in the
circumferential direction
4 Test personnel
The personnel performing ultrasonic guided wave testing shall be qualified in accordance with ISO 9712 or
with any another equivalent standard of the relevant industrial sector.
Training in the use of the specific equipment is required because there are significant differences between the
available systems and diagnostic approaches.
5 General
Ultrasonic Guided Wave Testing (GWT) uses elastic waves which are guided along the pipe wall and can
travel long distances, thus providing rapid near complete coverage of the volume of the pipe wall.
The typical test setup is comparable to conventional ultrasonic pulse-echo testing: an ultrasonic instrument
forces transducers in the probe ring to generate ultrasonic waves in the pipe wall which are reflected by
discontinuities and received by the same probe ring. The time-of-flight of the received signal indicates the
distance between the discontinuities and the probe ring. A single test with guided waves can cover a length of
pipe
...