solving real world integrity problems using 3d-laser scanning · api 653 criteria • the maximum...

Solving Real World Integrity Problems Using 3D-Laser ScanningThree Case Studies

Jessica DonaldsonCanadian Engineering and Inspection Ltd.Edmonton, Alberta, Canadawww.caneil.ca

ND

T in C

anada 2015 Conference, June 15-17, 2015, E

dmonton, A

B (C

anada) - ww

w.ndt.net/app.N

DT

Canada2015

Agenda

� 3D Laser Scanning: What Can It Do?

� Applications

� Case Study 1: 3D Laser Scanning of Visually deformed newly fabricated pipe bends

� Case Study 2: Scanning to Perform Fitness For Service Assessment of Y-Piping Spool

� Case Study 3: Engineering assessment of a large diameter storage tank and roof rafters

� Conclusions

� QuestionsNDT in Canada 2015 Conference

3D Laser Scanning

• Capture 3D documentation

• Can record complex structures and systems

with (depending on manufacturer):

– Distance accuracy up to ±2mm

– Range from 0.6m up to 130m

– Measurement speed: 40 million points/6 minute

scan

– Adjustable resolution

NDT in Canada 2015 Conference

3D Laser Scanning

• Constant waves of

varying length

• Upon contact with an

object they are

reflected back to the

scanner

(triangulation)


Scanning Equipment

• Similar to survey

equipment in size

• 200mm spheres

• 150mm spheres

• 6ft CF tripod

• 15ft elevator tripod


Applications

• As-built

• Alteration

• Documentation

• 3D Virtualization

• Inspection

• Flaw/Deviation Analysis

• Accuracy for Fitness for Service

Assessments


Methods of Geometric

Measurement

• Traditional Methods and Limitations– Tape measure, level, plum bob, sweep board, etc

– Surveying

– Time consuming and difficult to get many geometric data points

– Several approximations must be made

– Where is the worst spot when looking at damage?

• Different approach – 3D Laser Scanning as a tool– Involves creating virtual models of real world objects

– Models are created from a point cloud (40 million points generated in a 6

minute scan)

– Each point gives the exact location from a detected surface


Processing Data

• Modeling software combines point cloud data into an

accurate model


Example: Tank External Scan


Example: Tank Internal Scan


Example: Facility (as-built) Mapping


Limitations


Case Study 1 :3D Laser Scanning of visually deformed newly fabricated

pipe bends

• Background Information

– Three newly fabricated pipe bends

– O.D. of 914 mm; the three bends had angles of 42°, 21°,

and 41°

– Out of roundness identified as a concern by visual

inspection

– Ends of bends have an out-of-roundness tolerance of 1%,

and the rest of the bend can have an out-of-roundness

tolerance between 1% to 3% (ASME B16.49 paragraph

12.1).

Pipe Bends and 3D Laser

Scanning Setup


Ideal 3D Model of Bends


End Deviation

• Maximum Out of Roundness: 8.6mm (0.94%)


Front Face Deviation

• Max Deviation: 8.6mm (0.94%)


Arc Bend Deviation

• Maximum Deviation: 9.5mm (1.04%)


Conclusion

• All three bends meet the tolerance

requirements for out-of-roundness as per

ASME B16.49, for the areas that were

scanned.

• Bends Fit for Service


Case Study 2:Scanning to Perform Fitness For Service Assessment of

Y-Piping Spool

• Y-spool was permanently distorted when an expansion joint

attached to an associated pump failed. The expansion joint

was replaced but the client wanted to ensure the Y-spool was

still fit for service.

• No cracking or crack like indications found with NDE.

• Replaced the failed expansion joint.

• Requested to perform 3D laser scan of the Y-spool and then

perform an API 579-1/ASME FFS-1 Fitness-For-Service

assessment.


Y-Spool Point Cloud image from 3D Scan


Y-Cross Section Mapping


Analysis

• The Y-section was modelled for a Level 3 assessment

• Deformation data was taken from 3D laser scanning

results and the worst areas were modelled. Five

deformed areas with a deviation greater than 0.4”

were considered in the analysis

• Straight segments of the Y-spool deviations were

within the permissible 1% out-of-roundness

tolerance and therefore not modeled for Level 3

analysis


Y-Section Model


Fixed Geometry restraints, internal pressure and fluid

density loading was applied to the model for the Level

3 assessment


Stress AnalysisMaximum of 7500psi


Increasing Pressure SimulationsApproach yield at 120psi


Conclusion

• Based on the results of the assessment, it was

determined that the Y-spool was fit-for-service

provided:

– Visual monitoring of the Y-spool and attached piping for crack

appearance, increased deformation, and any other changes

– Repeat 3D laser scanning assessment to monitor deformation

– no cracks or crack-like flaws exist or develop on the welds of

the Y-spool by performing periodic NDE examination

– Cause of expansion joint failure investigated to ensure there

is no repeat occurrence of failure


Case Study 3:Tank Deformation and FFS

• Internal inspection of a large diameter storage tank

to API 653 requirements

• Geometric evaluation of tank shell

• Baseline shell evaluation for future inspection

• Tank

– Diameter: 85ft

– Height: 40ft

– Nominal Capacity: 40395 BBL


Tank Overview


Point Cloud ModelTotal of 8 scans with tolerance of ±3mm


Cleaned 3D Point Cloud for Shell Geometric Evaluation


Ideal 3D Model


Tank Scanned Model


Maximum Bulge: 1.65in.

Maximum Dent: 2.05in.


API 653 Criteria

• The maximum radii tolerance for this tank, as per

API-653 for reconstructed tanks and the API 650

construction code, is ¾ in. (19 mm) measured at 1 ft.

above the shell to bottom weld.

• API 653 also states that the tolerances above the 1 ft.

level are not to exceed 3 times the tolerance at the 1

foot level. This restricts the out of roundness above

the 1 ft. mark to 2 ¼ in.


Comparison of Tank with Tolerances


Conclusion – Shell Evaluation

• Deformations found to be acceptable based

on the code requirements.

• Recent edge settlement survey showed tank

to be in good condition.

• API 653 internal and external inspection

performed at the time of scanning.

• Recommended the tank as fit for service.


Rafter Evaluation

• Tank has 43 rafters and one central column

• Visual inspection of the rafters revealed

deformations that required further

investigation

• 8 scans were done to model rafters and tank

internals


Rafter Point Cloud Model


Cleaned up Rafters


Rafter Point Cloud to 3D Model


Analysis of Worst Case RafterMaximum Deviation: 1.20 in.


Conclusion

• There are no tolerance limits specified in API 653 for

bending of roof rafters.

• Analyzing the worst case condition, with full snow

load and vacuum applied, the rafters had an average

maximum stress of about 19000 psi. This is still well

below the yield strength and did not signify any

integrity concerns.

• Tank and roof rafters fit for service.


Conclusions

• Laser scanning has proven to be a valuable tool for

dealing with several asset integrity challenges that

involve dimensional analysis

• Improved accuracy of Engineering Assessments API-

579 Fitness-for-Service (Model what’s actually there

instead of guessing and approximating)

• Especially useful in the following areas:

– Records management

– Alterations/modifications

– Inspection / QC

– Fitness-for-Service and integrity engineering


Questions


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