Bringing safety, productivity with laser scanning
Author: Anzhelika Kuznetsova
Oil refineries, smelters and other plant environments are very complex structures and can present major hazards. Any construction and rebuilding of highly complicated plants and shops require detailed engineering based on actual site data, and strict dimensional monitoring of construction and installation activities.
In most rebuilding projects, new structures and utilities to be installed are connected to the existing infrastructure, so high tie-in precision is necessary. It is quite common in the industy that the as-built drawings are not available, or the construction and installation works do not meet quality standards. There is a great need to collect actual field data on the existing structures and utilities.
IBCON, a provider of high quality input data for survey, design, and construction of brand new and rebuilding projects, has been involved in large-scale industrial projects providing IT support for the past 11 years. Today, IBCON focuses on oil refineries and smelters using Leica Geosystems technology and AVEVA software.
Regaining trust in construction
One of IBCON projects efficiently using these technologies is the IT support for a smelter construction, the Kola Peninsula. As the customer worked on the project, it faced certain negative factors that prevented it from meeting the deadline, and led to financial losses. To rectify the situation, the contractor hired IBCON construction and rebuilding IT support services, enabling project completion in due time.
The job was to reconstruct the geometry and position of the existing structures to be built/rebuilt as fast as possible. The total area amounted to 95,200 sq m. The data were presented as a number of reports for the customer. The reports indicated any deviations between as-designed and as-built geometry and position of the structures. These reports have helped the customer to make smart project decisions.
The project faced many challenges, such as:
- Huge scope
- Tight schedule
- Harsh working conditions on the operating facility (vibrations, steam, dust, hazardous releases)
- Many running vehicles and operating equipment on the site (welding machines, cranes, trucks, etc.)
Conventional land surveying in such conditions is extremely difficult, and just impossible in some cases. A fast, highly efficient process without compromising survey accuracy and high resolution was needed.
Delivering results with laser scanning
The IBCON team used a Leica ScanStation laser scanner. Laser scanning technology minimises surveying time even for sites as large as tens of thousands sq m, and inaccessible areas while preserving high accuracy and resolution.
Laser scanning technology does not require an exact scanner orientation as is the case with the conventional surveying. It enables scanning in restricted view conditions and acquires more information about any hidden structures. Just three company experts carry out field and in-house laser scanning projects in IBCON, greatly saving efforts.
Leica Cyclone software is used for primary laser scanning data processing. After that, they are aligned to the facility’s coordinate system. Laser scans are stitched by marker or point cloud matching.“The software is very useful since in real life situations, target markers are often obstructed, such as when construction machinery is in operation,” said Sergey Mitrakov, IBCON surveyor.
The mean measurement error is ≈ 7 mm per 100 scanner locations. Subsequently, the scanned point cloud is exported to AVEVA E3D that builds a 3D model. Each object (reinforced concrete structures, steelworks, equipment, etc.) is identified within the cloud point to build the geometry of the 3D model. Attributes taken from the as-designed and as-build documentation, a unique index, and a hierarchy level are assigned to each 3D object within a model.
The resulting extended 3D model is a tool for generating reports as required by the customer. A 3D model built from the laser scanning data is matched against a 3D model provided by the project developer. In this way, any deviations of the installed structures from their intended positions are easily identified and listed in the reports.
In the context of today’s extensive construction environment and its demand for prompt and mass-scale data acquisition about each structure built on a site, laser scanning technology provides complete visibility of any construction object. Such projects cannot be implemented with conventional land surveying tools as the data acquisition rate is very low.
“Surveying with the Leica ScanStation P20 laser scanner makes site surveys easy and visualises complex structures in a simple way,” said Mitrakov.
The above described services are performed as cycles, prior to project completion, and commissioning. IBCON’s construction and rebuilding project IT support services help the customer make prompt decisions at every stage using accurate and timely reports to monitor project completion, and reduce extra error rectification costs.