Hasan Ozgur Unver

Dimensional control surveying is the technique and science whereby 3-dimensional spaces are accurately measured to determine the area between points, creating digitally mapped distances and angles.

Dimensional control surveying has been used for decades in the world’s large jacket and fabrication facilities. However following the Piper Alpha disaster in the North Sea in 1988 in which 167 men lost their lives, Dimensional Control survey began to be used on offshore installations, as the subsequent enquiry found that one of the causes of the fire was naked flame from offshore fabrication, welding and grinding in a highly explosive environment. Dimensional Control survey eliminates the need for this.

Survey Instrument: Leica 1203, Accuracy +/-1mm.

Suitable for application in:

• Industrial Measurement – 3d capture

• Replacement Pipe-work – Clash checking

• Alignment surveys – Structural steel surveys

• Drill rig alignments – Structural monitoring

• Fabrication Surveys – Ship Conversion / New building

• Laser scanning – 3d modeling

Dimensional control can be defined as the process of acquiring accurate dimensional documentation that is spatially referenced to a known or established benchmark. Using the latest survey technology from Leica Geosystems Surveyors can measure and produce 3d Cad models from single pipe spool replacements to full FPSO/Jacket construction surveys.

The captured data can be transformed to AutoCAD or Micro-station, 2D drawings or Point Cloud data from our Laser Scanners.

 

Aims

• Provide confidence to Project Managers

• Allow no surprises during integration

• Reduce project hook-up schedule

• Reduce direct man hours of hook-up

• Risk mitigation

 

Benefits

• Budget control

• Mitigate rework

• Project costs reduced

• Indirect costs savings

• Mitigate Risk

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Fabrication Surveys – Ship Conversion / New Building

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• Dimensional survey all major lift components, modules, pipe racks, flare.

• Dimensional survey hull deck module support footings.

• Analyse fabrication tolerance build up and produce 3D best fit positioning to design.  Provide shimming thicknesses.

• Survey all flanged piping tie-in point interfaces on modules, and pipe rack.

• Produce new fabrication isometrics with true interface dimensions.

• Provide position of installation aids, bumpers, guides.

• Spool fabrication verification checks.

 

Turret Survey

     

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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                                                  Buoyancy Cone                                                                                                                      Turret Structure

          

All critical dimensions will be surveyed and make sure that all errors within acceptable tolerance.

 

Module As-Built Survey

 

A local network of survey points will be established around the respective Module.

This will allow a series of detail points to be observed on the Primary steelwork at predetermined locations.

These detail points will reflect the position of each leg on the module and the elevations found on the Interface Plates of each leg on the module.

The detail information will be “best-fitted” to suit the Primary steel identified on the Design drawings.

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Hull Full As-Built Survey

 

Survey as built position of pipework, steelwork and other appurtenances (cable trays, lighting stands, telephone stands, walkways and handrails etc) in critical / identified areas for clash check purposes prior to module installation. A 3D model will be produced in AutoCAD to use for Clash Checking in Navis Works.

 

 

 

 

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Module Installation Clash Checks

 

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                                                          Clash Plot                                                                                                                     Module Installation

  

After survey of all existing deck obstructions and As-Build Survey of Modules Structures and Piping tie in Points.

Clash Check between All Deck Pipe Systems and with Surveyed Deck Obstructions. We overlay the As-Build Survey of Modules over the all existing deck obstructions in Navis Works. Produce clash plots & register.

 

3D Laser Scanning

 

 

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An advanced 3D laser-scanning service for mass capture of existing facilities. The data can be directly interfaced with all CAD platforms including Autocad, Microstation, PDS and PDMS to allow clash verification between as-built scan data and new design.

Conceptual design utilizing laser scanning to verify a concept prior to moving on to detail engineering

Detail engineering utilizes a mixture of Laser scanning to carry out complete As- Built of areas and verification clash checks carried out between laser scan and proposed 3D design, and utilizing Dimensional control service to provide sub mm accurate information of any item offshore true " Tie In " point location and face of flange geometry.

Fabrication interfaces, utilize dimensional control service to ensure zero risk through interface management and control service.

Installation of equipment using dimensional control to position accurately all new equipment ensuring no clashes and everything fits first time.

 

       Benefits

• High speed Laser Scanner.

• High resolution scans.

• Project accuracy +/- 5mm.

• Accuracy (+/- 1mm) EDM control survey.

• Comprehensive data capture.

• Short processing time.

• User friendly deliverable. Point clouds accessible from PDMS, PDS, AutoCAD, Micro station.