High-resolution laser scanning technology empowers API inspectors and engineers to rapidly perform a comprehensive and detailed analysis of storage tanks, allowing decision makers to act quickly and confidently. In the past, the turn-around time for 3D analysis results could take several weeks. This led to additional downtime or information that was no longer useful because the tank had already been put back into service. However, recent technological developments now enable 3D analysis to be completed in a matter of hours, providing immediate feedback to stakeholders.
New technologies in data registration eliminate the need to place targets in-field, reducing training and onsite preparation. Advanced algorithms are used to evaluate as-built conditions by reconstructing the storage tank in 3D with survey grade accuracy from hundreds of millions of data points. Improvements in computing power and software capabilities allow 3D analysis to be completed in less than an hour once scanning is finished.
These near real-time results can reveal areas that are in need of further investigation in order to coordinate other inspection services. Instead of returning to the site to conduct additional inspections, field crews can immediately focus their attention on identified high priority areas. As a high-resolution 3D image of the storage tank, 3D scanning can eliminate many of the routine, time consuming tasks performed by tank inspectors, freeing them up to focus on tasks they are trained to do.
Unlike traditional inspection techniques, 3D scanning quickly captures the entire storage tank structure in unprecedented detail to create a digital twin, minimising scheduled downtime and exposure of personnel to potentially toxic environments. While an inspector’s ability to see is limited inside a dark storage tank, a 3D scanner can measure with unparalleled detail and clarity using infrared laser pulses. Not only can scans be captured safely from the ground, in the dark, and without interference with onsite activities, further analysis can be conducted without the need to return to site.
Accurate 3D models are used to identify deformations of each component from the design dimensions. These analyses include shell settlement, edge settlement, shell roundness and verticality, shell peaking and banding, floor and roof settlement, column, girder, and rafter deflection, and floating roof rim space. Holistic analysis of the storage tank allows inspectors to trace the root cause of a failure. If a problem area is identified, engineers can easily isolate and extract data to perform additional investigations and monitor changes during repairs. 3D scans are therefore an invaluable digital archive of the tank.
From the same 3D model, it is possible to perform tank strapping/calibration and secondary containment sufficiency assessment. This significantly reduces the cost and time to perform all the necessary assessments for each storage tank. For tank strapping/calibration, software can be used to automatically extract dimensions and volumes occupied by deadwood, substantially reducing field effort. For externally scanned storage tanks, flow modelling can be applied to determine the precise volumetric capacity of the secondary containment structure. If found to be inadequate, the 3D model...
Written by Josiah Lau, Novlum Inc.
This article was originally published in the Spring 2021 issue of Tanks and Terminals magazine. To read the full article, view the Spring issue here. And to sign up to receive a free regular copy of the magazine, click here.
Read the article online at: https://www.hydrocarbonengineering.com/tanks-terminals/05032021/adding-dimension/
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