Real Time Corrosion Mapping System: A
Comparative Study Bob Lasser, David Rich
Imperium, Inc.
Beltsville, MD
Josh Fontenot, Tim Borel
Advanced Corrosion Technologies & Training (ACTT)
Sulphur, LA 1
About Study
• Wanted to compare Imperium’s FirstMap Corrosion
Imaging system to Phased Array UT (PAUT)
• Investigated resolution
• Other factors included ease of use, cost, training
requirements
• Joint study between Imperium, Inc. (Beltsville, MD)
and Advanced Corrosion Technologies & Testing
(Sulphur, LA)
About Imperium
• Founded in 1996
• Leading developer of ultrasound camera technology
• Systems in petrochemical, aerospace, medical fields
About Advanced Corrosion
• Founded in 2002
• Extensive experience in advanced NDT methods
• Presence in several locations on Gulf Coast
Why Industry Needs A New NDT
Device
•
•
•
•
•
•
Lack of trained NDT personnel
Lack of confidence in thickness readings, missed
corrosion
Need higher POD
Need areas where AUT can’t reach
Advances in imaging technology
•
A picture is worth 1000 words
Time and cost pressures – “FirstMap” diagnostic
tool quickly identifies areas for further investigation
FirstMap Advantages
• Images are easier to interpret
• FirstMap provides an actual image of the defect including
thicknesses
• High resolution
• Higher confidence than single thickness readings
• Not effected by beam dispersion
• Built in delay line
• No extensive training required; less trained technician
• Real time
Evolution of UT Methods
A-scan
B-scan
C-scan
B-scan to C-scan
Defect
Defect
Imperium’s Patented Architecture
Applies optical imaging techniques to ultrasound
Optical Architecture:
Flash
Lens
Optical Sensor (CCD)
(2) F1 Acoustic Lens
Ultrasonic Sensor
Ultrasonic Architecture:
Acoustic Flashlight
Note: CCD means Charged Coupled Device
Pulse Echo – 50/50 Beamsplitter
Sound
Transmitter
Array
Subsurface
fault
Video
Water
Lens
Acoustic
beamsplitter
Target
Pulse echo
image of quarter
Imaging Array – 100 micron pixels
120 rows x 120 columns = 14,400 pixels
PIPELINE CORROSION MAPPING
SCANNING & STITCHING
• Make large mosaic images from smaller
ones
• Capture both C-scan and thickness
• Uses encoder attached to camera
Tilting encoder
Optical image of corrosion inside pipe
Dual element transducer
Scanned/stitched image of corrosion inside of pipe
INSPECTING STORAGE TANK
BOTTOMS WITH FIRSTMAP
Compare FirstMap’s
easy to interpret readout
MICROBIOLOGICAL INDUCED CORROSION
Black areas indicate MIC, note the veins of MIC also
PIPELINE CORROSION MAPPING
Benefits to NDT Industry
• Broad application base
•
•
•
•
•
•
• Pipelines, storage tanks, pressure vessels
Find corrosion faster
Find smaller amounts of corrosion
Does not sacrifice any current data quality
Provide better information to end customer
Better tool to provide comparisons
Use Level 2 thickness inspector to generate
images, not just readings
• Get to areas where current tools can’t go
B-scan vs. C-scan
Phased Array
FirstMap
Resolution Study:
FirstMap vs Phased Array
• Investigated axial, lateral, and elevation
resolution
• Used Omniscan MX2
• Both systems working at 5 MHz
• Did mathematical study, then took data to
compare expected results
Omniscan
PAUT System Test Settings:
Probe:
5L64-NW1 (5 MHz)
Wedge:
SN1-0L5L64
Mode:
Phased array
Focal Depth:
0.1”
Focal Law:
Linear sector with overlap
Skew Direction:
900 (straight down mode)
Scan Offset:
0
Index Offset:
0
Element Quantity:
8
First Element:
1
Last Element:
64
Thickness:
0.25”
Surface:
Flat plate
FirstMap System
Frequency:
Number of Pulses:
Gate start:
Gate width:
5 MHz
1
0.1”
0.5”
Phased Array Theoretical
Resolution
Lateral (X):
ΔD = (0.44 x V) / (F x sin (θ/2))
Axial (Z):
ΔZ = V x T/2
Elevation (Y):
Defined by the length of the array elements,
and will be on the order of several millimeters
Source: Olympus NDT Manual
21
Resolution Summary
INSPECTION
SYSTEM
AXIAL
RESOLUTION
LATERAL
RESOLUTION
ELEVATION
RESOLUTION
FirstMap™
1.5 mm
0.1 mm
0.1 mm
PAUT
0.3 mm
0.34 mm
> 1.0 mm
FirstMap
Omniscan: Amplitude
Omniscan: TOF
Comparative Study:
FirstMap, X-ray, Phased Array
Reviewed different techniques for corrosion
mapping
 Used common standards
 Recorded image quality
 Recorded time of setup, scan, training cost

Targets Studied
Stepped standard
Corrosion piece
8” diameter pipe
section
Stepped Standard
FirstMap
Phased Array
X-ray 192 iridium
0.25” Corroded Steel Panel
FirstMap
Phased Array
X-ray 192 iridium
8” Diameter Pipe Section
FirstMap
Phased Array
X-ray 192 iridium
Corrosion Mapping Comparison
FirstMap™
Phased Array
with Scanner
Iridium-192
Radiography
Equipment &
Related Costs
$45K
$70K
$100K
Daily Cost
~$800
~$1200
~$2000
5 minutes
15 minutes
30 minutes
Required
Training
16 hours
160 hours
400 hours
Required
Experience
Level I or
Level II
Level II NDT
Advanced
Availability of
Technicians
Available
Limited
Very limited
1
1-2
2
NDT Method
Inspection time
per square foot
(includes setup)
Required
Technicians
Advanced Corrosion Technologies
“The probability of detection is far superior to
standard thickness readings. FirstMap™ is a
diagnostic tool that can instantly detect subsurface
corrosion down to 1 mm pits. We are now able to
quickly and easily identify problem areas that could
potentially lead to much bigger issues.”
-Josh Fontenot,
Director of Technologies, ACTT
Imperium, Inc.
5901-F Ammendale Rd
Beltsville, Maryland 20705
301-431-2900 / 301-431-0200 fax
www.ImperiumInc.com
35