correct placement of cursors on the surfaces and
confirms that the point cloud data precisely repli-
cates the surface being measured.
Summary
In summary, RVI using video borescopes can assess
the internal health of industrial gas turbines and
help avoid false calls that could lead to increased
downtime and significant unplanned expenses.
Although current generation video borescopes
require a significant initial investment, they can
deliver a substantial return on investment (ROI)
even after just one inspection event.
The results provided can be more accurate,
leading to safer and more efficient operations with
lower ownership and operational costs.
The key to achieving this is to have the proper
equipment operated by trained and qualified tech-
nicians, certified by their employers to perform
specific RVI tasks on a particular asset.
AUTHOR
Paul Thompson: Managing Director, REVEAL RVI, Savannah,
GA revealrvi@icloud.com
CITATION
Materials Evaluation 82 (7): 40–48
https://doi.org/10.32548/2024.me-04450
©2024 American Society for Nondestructive Testing
REFERENCES
1. Allgaier, M. W., and G. C. Sayler. 2011. “Angle of view.” The
NDT Technician 10 (4): 6–8.
2. “History of Lenox Instrument Company, 1900–1920,”
https://www.lenoxinst./lenox_history_boroscopes.html.
3. “Gage repeatability and reproducibility,” https://asq.org/
quality-resources/gage-repeatability.
4. “The real cost of a forced outage in power
generation,” https://www.linkedin.com/pulse/
real-cost-forced-outage-power-generation-assetsense-dyzgc.
FEATURE
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REMOTEVT
48
M A T E R I A L S E V A L U A T I O N • J U L Y 2 0 2 4

ROBOTIC VISUAL INSPECTION IN
CONFINED SPACES
BY EKKEHARD ZWICKER, BRANDON DEBOER, MARKUS WEISSMANN, AND ANTOINE CHEVALEYRE
Robotic visual inspection presents a promising solution to the challenges
posed by confined space inspection, offering enhanced efficiency,
accuracy, and safety.
Introduction
The latest advancements in robotic visual
inspection technology—including the
generation of digital twins, the tagging
of inspection data within asset models,
and the implementation of semi-au-
tonomous control—demonstrate how
robotics can effectively tackle the chal-
lenges of inspecting confined spaces.
Localization technologies such as lidar
(light detection and ranging) and 3D
modeling are key for effective con-
fined-space navigation. Maintaining
image quality in robotic visual inspec-
tions is also important, to ensure compli-
ance with industry standards.
The experimental validation that
follows evaluates the technical capabil-
ities of robotics and pole cameras for
confined space inspection. This includes
visual examination, ultrasonic thickness
readings, and 3D surface scans. The
integration of digital twin technology
streamlines data management and facili-
tates post-inspection analysis.
Robotic visual inspection ultimately
offers numerous benefits, including
high-quality and reproducible data,
reduced outage time and costs, process
improvement through automation, and
increased safety by minimizing human
entry into confined spaces.
Challenges with Confined Space
Inspection
Inspecting confined spaces presents
several challenges and risks due to
the unique nature of the environment,
including [1, 2]:
Ñ Limited access. Confined spaces are
typically difficult to reach and may
have restricted entry points, making
it challenging for inspectors to thor-
oughly examine the area.
Ñ Poor visibility. Many confined spaces
have limited lighting or may be
completely dark, hindering the ability
to see potential hazards or defects.
Ñ Restricted movement. Inspectors
may face difficulties maneuvering
within confined spaces due to narrow
passages, obstacles, or equipment
obstructions.
Ñ Communication challenges.
Communication between workers
inside a confined space and those
outside can be challenging due to
physical barriers or poor reception,
increasing the risk of accidents or
delays in emergency response.
Ñ Time constraints. Inspections
in confined spaces often require
careful planning and coordination to
ensure the safety of personnel. Time
constraints may arise due to limited
availability of access or the need
to complete inspections quickly to
minimize disruption to operations.
Ñ Training requirements. Inspecting
confined spaces requires specialized
training and expertise to identify
potential hazards and implement
safety protocols effectively. Lack of
proper training can increase the like-
lihood of accidents or errors during
inspections.
Ñ Documentation and reporting.
Proper documentation of confined
space inspections is crucial for regu-
latory compliance and risk manage-
ment. However, maintaining accurate
records can be difficult, especially in
remote or hazardous environments.
Ñ Emergency preparedness. In the
event of an accident or emergency
inside a confined space, rescuing
workers can be complex and
time-consuming. Inspectors must
be adequately trained in emergency
procedures and have access to the
appropriate rescue equipment.
Ñ Regulatory compliance. Confined
space inspection must adhere to
stringent safety regulations set
by authorities such as OSHA (the
Occupational Safety and Health
Administration) in the US. Failure to
comply with these regulations can
result in legal repercussions and jeop-
ardize worker safety.
Addressing these challenges requires
careful planning, appropriate training,
and the use of advanced technologies
and safety measures to ensure the effec-
tiveness and safety of confined space
inspections.
Limitations of Remote Visual
Inspection
Remote visual inspection (RVI) con-
ducted in confined spaces such as
pressure vessels, reactors, and boilers,
whether using a remote-controlled
crawler or a camera mounted on a pole,
often relies heavily on manual control.
The crawlers are piloted remotely, data
is captured manually, and reports are
subsequently created by transferring this
information into predesigned templates.
This disconnected approach presents
several challenges. First, there is no
direct link between the captured data
and its specific location within the asset.
Second, this manual process (Figure 1)
demands significant additional effort to
leverage the data for internal processes
and integrate it with the digitalization
strategies of asset owners and operators.
VT
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FEATURE
J U L Y 2 0 2 4 • M A T E R I A L S E V A L U A T I O N 49