The following slides present the basis of Guided Wave Theory and Technology and how this portable system maximizes the efficiency of a corrosion management program.

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Presented by: Mohammad Javad Ranjbar
Supervisor: Dr. Sodagr
01 March, 2015 Petroleum University of Technology
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Today’s inspection challenges are becoming more and more
focused on productivity combined with high quality results.
one of the main concerns in 90s was focused on corrosion under
insulation in oil, gas and petrochemical industry.
The following slides present the basis of Guided Wave Theory and
Technology and how this portable system maximizes the efficiency of a
corrosion management program.
Introduction
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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• Low Frequency Ultrasonics
• Used to Screen in-service pipes and pipeline over long distances
• Can provide significant reduction in operating costs
• Inspect pipes with limited access from a single position
• Pinpoint locations requiring further inspection
• Also known as Guided wave and LRUT, or long range ultrasonic
testing
Introduction
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
3
History of the development of
GW testing for pipes
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
Imperial College NDT Group, 1991
1987
Started at Imperial College
London
1992
Understanding of guided wave
properties
1995
Understanding of guided wave
reflections from simple defects
1997
Development of transducers and
signal processing
1997
Commercialisation (licensed by
Imperial College, Guided Ultrasonics
Ltd.)
2009
Procedures formalised in
published Standards
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Applications and Industries
Basics of Guided Waves
System Overview
Inspection Sequence
Standards, Codes, and Training
Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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 Refineries
 Power Generation Plants
 Pipes and Piping in gas transportation stations
 Onshore pipelines
 Offshore risers and other piping systems
Industries
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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 Inspection of above ground conventional and coated pipe
 Detection of corrosion at supports and pipe racks
 Inspection of through-wall pipe
 Detection of corrosion under insulation (CUI)
 Inspection of buried pipes
 Inspection of vertical pipes
 Road Crossings
Corrosion detection / in-service pipes and pipelines
Applications
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Cosiderations
 But it’s a screening tool:
 Areas of concerns need to be addressed with other NDT
techniques.
 Conventional Ultrasonics or Phased Array can be used to
confirm the pipe condition.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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 Inspecting with guided waves avoids unnecessary excavation,
coating removal, or scaffolding if no flaw is detected.

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Applications and Industries
Basics of Guided Waves
System Overview
Inspection Sequence
Standards, Codes, and Training
Data Analysis
Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
9
Inspection with Conventional Ultrasonics
• Localized inspection
• Underneath or in the vicinity of the sensor location
• Must remove all coverings, condition pipe for UT inspection
• High freq. ranges
• Respose time is micro sec
Inspection with Guided Waves (Long-Range Ultrasonic Testing)
• Screens the entire pipe wall
• low freq. range : below 100 kHz.
• Long inspection range (182 meters/600 feet)
• From a single inspection position
• On each side of the probe collar
• Response time is mili sec
Guided Waves Vs.
Conventional Ultrasonics
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Guided wave generation
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Data Analysis
Conclusion
Types of Guided Waves
GUIDED WAVES
Boundary Specific
Surface waves Rayleigh waves
Interface waves
Love waves
Scholte waves
Structure Specific
Plate waves Lamb waves
Rod waves
Rail waves
Cylindrical waves
Longitudinal
Torsional
Flexural
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Guided waves in pipes
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
13
Concept of long range inspection
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Guided wave velocities are dispersive,
Their velocity changes with frequency
L- and T-wave velocities do not vary with frequency
Dispersive Vs. Nondispersive
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Unique Characteristics
There are two different types of dispersion curves
Phase Velocity Dispersion Curves
Velocity at which a constant wavelength is generated for a given frequency
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Factors Affecting Performance
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
SurfaceCondition
• Bare metal
• Smooth well
bonded paint
• FBE
• Light pitting
• Heavy pitting
• Plastic, e.g.
PVC
• Buried (earth
or sand)
• Bitumen
coated
• Concrete
coated
Geometry
• Straight
lengths
• Infrequent
swept/pulled
bends
• Attachments /
brackets
• Branches
• Multiple
bends
• Flanges
Contents
• Gas
• Low viscosity
liquid
• High viscosity
liquid
• Waxy or
sludgy
deposits
Long Range
~200m
Short Range
~20m or less
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GWT Capabilities
• Rapid screening for in-service degradation
• 100% coverage
• Externally applied
• Lines can be tested in-service
• Temperature up to 250°C (482°F)
– Standard set-up up to 125°C (257°F)
• Diagnostic length not a constant: 5 to 100m each side
• Detects internal and external metal loss
• Cross-section change ≥ 3%
• Semi-quantitative assessment of flaw extent (focussing)
• Longitudinal accuracy ~100mm
– Dependent on frequency and wave mode
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Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion

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Applications and Industries
Basics of Guided Waves
System Overview
Inspection Sequence
Standards, Codes and Training
Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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UltraWave LRT
The system features the UltraWave LRT instrument,
which is secured in a backpack, a rugged touch-screen laptop
with software, flexible inspection collars, and all the necessary
tools to perform an inspection.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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• Probes assembled on
predefined bands for each pipe
diameter (Standard kit 2 – 24 in.
OD).
• Bladder inflated to ensure good
contact for the inspection.
• No couplant is required.
•
Fast and easy setup on the pipe
• Inspections with limited access
• Light and compact transport
Inspection Collar
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Acquisition Unit and Laptop
• Battery operated,16-channel,
with broadband frequency
range: 15 to 85 kHz.
• Total inspection length: 182
meters (600 feet) in optimal
conditions (91m/300 feet
bidirectionally).
• Getac V200 rugged, industrial
touch-screen laptop computer
with sunlight-readable display.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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UW Software
•
•
•
•
Setup Wizard.
Color mapping.
Focusing modes.
Easy reporting.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Applications and Industries
Basics of Guided Waves
System Overview
Inspection Sequence
Standards, Codes, and Training
Data Analysis
Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Inspection Sequence
1)
2)
3)
4)
5)
6)
Pipe sketch
Collar installation
Axisymmetric scan
A-scan analysis / features localisation
Active focusing if necessary
Synthetic focusing (can be done
during post-processing)
7) Defect confirmation (UT or phased
array)
8) Second acquisition, if necessary
9) Final analysis and reporting
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Pipe Sketch
• A drawing with notes on the pipe configuration is
mandatory for further analysis.
• Key features and there locations are identified with as
much or as little information is known.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Collar Installation
Surface conditioning
Pipe thickness measurement
Band positioning
Bladder inflation
Wiring and coupling validation
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Defining the Setup
• A user-friendly, step-by-step wizard is available in the
software to build the setup
• Information about the line dimension, location, thickness,
material, and coating are entered before acquisition
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Axisymmetric Scan
 Guided waves are pulsed all around the pipe with no time delay
 Multiple frequencies are acquired simultaneously
 Analysis is performed on the most sensitive frequency
 A-scan is selected with the horizontal red cursor
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
Data acquired from 15 to 85 kHz with steps of 1 kHz
Defects
FlangeWeld
Dead Zone
80kHz Weld
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Preliminary A-Scan Analysis
• Known feature identification (weld, flange, visible indications).
• Distance amplitude correction (DAC) curve positioning.
• Pipe schematic updated with pre-selected symbols.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Active Focusing
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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C-scan view of unrolled pipe (channels vs. distance at 1 frequency).
Generated considering the phase velocity of the received modes (from
flexural).
Provides the axial position and circumferential extent of all defects.
Post-processing tool.
Displays the entire inspected zone.
Synthetic Focusing
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Defect Confirmation
• Inspect the zone of concern with complementary NDT
techniques.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Mode Conversion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Focal Respose – Constant Area
Defect shape
with
constant
area loss
Axisymmetric
respose
showing
Amplitude
focal respose
showing
angular
distribution
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Focal Respose – Constant Angle
Defect shape
with
constant
area loss
Axisymmetric
respose
showing
Amplitude
focal respose
showing
angular
distribution
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Pipe Support
with corrosion
Pipe Support
with corrosion
Corrosion
WeldWeld
Dead Zone
Weld
Axisymmetric F-Scan view
Inspection of a pipe with multiple indications
Supports appears at the lower frequencies while some
corrosion also shown at the higher frequencies
Pipe Support
with corrosion
between the
weld & support
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Reporting
• Annotations lists, with corresponding screen shots, are
automatically compiled in the report.
• Laptop integrated camera allows for quick picture
importation.
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
39
Applications and Industries
Basics of Guided Waves
System Overview
Inspection Sequence
Standards, Codes, and Training
Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Codes and Standards
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
• Basic requirements for guided wave
testing of pipes, pipelines and
structural tubulars
BS 9690 and
9690-2
• Standard Practice for Guided Wave
Testing of Above Ground Steel
Pipework Using Piezoélectric Effect
Transduction
ASTM : E2775 -11
• : Long Range Inspection of Above Ground
Pipelines and Plant Piping Using Guided
Wave Testing with Axial Propagation
ISO / TC 44 & IIW
• : General rules for how to study flaw
detection of a pipe by pulse echo
method using guided wave
JIS/NDIS 2427
• IN PROGRESS
ASME Section V
Article 18
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Training and Certification
BS/EN 473 : General principles for qualification and certification of
Guided
Wave Testing personnel
BS/EN 14748 : Non-destructive testing. Methodology for qualification of
non-destructive tests
CSWIP ES NDT 12 04 /DOCUMENT No. CSWIP-ISO-NDT-11/93-R-
PCN GW GEN/Appendix A/General and Specific Requirements for
Qualification and PCN Certification of Guided Wave Testing Personnel
SNT-TC-1A (ANSI/ASNT CP-105-2011)
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
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Conclusion
Introduction
Applications
Basics of
Guided Waves
System
Overview
Inspection
Sequence
Standards,
Codes &
Training
Conclusion
43
High productivity inspection with long-range
coverage and rapid screening.
100% screening coverage of pipe wall, 360
degrees around the pipe circumference.
Cost reduction for excavation, scaffolding, and
insulation removal.
Cost effective solution for pipe integrity
management programs.
In-service inspection (no production
shutdown).
References
1. Olympus Webinar, “An introduction to guided waves, theory and
application”
2. M.J.S. Lowe, P. Cawley, “Long range guided wave inspection
usage-current commercial capabilities and research
directions”,2006
3. ASTM E2775-11
4. BSI BS9690-1
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THANK YOU FOR YOUR ATTENTION
Your Questions are Welcomed…
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