Experience in Engineering Repairs for Mechanical Damage and Cracking in PipelinesAdam Thistlethwaite BEng MSc MBA CEng FIMechE
Global Service Line Director On-Stream Services
Chair – ASME PCC-2 Subgroup Mechanical Repair
© TEAM, Inc. All rights reserved.
Agenda
• About TEAM
• Design challenges for mechanical damage & cracking
• Advanced analysis of repair design for
• Cracking
• Mechanical damage
• Case studies
© TEAM, Inc. All rights reserved.
Comprehensive Portfolio of Services
3
WHAT WE DO – A Reliability Partner
INSPECTION & INTEGRITY SERVICES
InspectionInspection
Integrity Management
and Performance
SolutionsConventional
NDE
Advanced NDE
Pipeline Integrity
SolutionsTank
Management Solutions
IMPS
CNDE
ANDE
PIS
TMS
RELIABILITY & REPAIR SERVICES ADVANCED INSPECTION & ENGINEERING
Asset Integrity & Reliability
In Line Inspections
Advanced Engineering
Advanced Digital
Imaging
INS
AE
ADI
Maintenance& Repair
Maintenance& Repair
Machining, Bolting and
Vapor Barrier-Weld Testing
ServicesOnStream Services
Hot Tap and Line
Intervention Services
Valve Management
SolutionsEmission Control
Services
MBV
OSR
HTS
VMS
ECS
© TEAM, Inc. All rights reserved.
Design Challenges
• ASME PCC-2 contains several articles on repair technology used in the pipeline industry– Article 206 – Full Encirclement Steel Reinforcing Sleeves for Piping
– Article 210 – In-Service Welding Onto Carbon Steel Pressure Components or Pipelines
– Article 401 – Nonmetallic Composite Repair Systems: High Risk Applications
• Design guidance is aimed primarily at addressing local and general wall thinning
• Mechanical Damage and cracking presents some challenges in terms of engineering repairs– What thickness of repair is required to reduce the stress at the damage to an acceptable level
– How does the repair locally interact with the defect, filling dents, restricting crack opening
– Effect of installation pressure on repair performance…
– How far does the repair need to extend beyond the defect
• TEAM’s unique in-house program of advanced inspection, engineering and repair resolves these challenges, allowing the benefit of repairs to be fully evaluated
Mechanical Damage & Cracking
© TEAM, Inc. All rights reserved.
Type B Welded Sleeve Analysis
• Work done by TEAM’s Dr. Greg Thorwald & Carolyn Kolovich, presented at IPC 2020
• Study investigated the effect of three elements of repair design– Sleeve length beyond defect
– Installation pressure
– Nature of the sleeve/pipe surface interaction
• Repair length not impactful to stress intensity past 51mm from the edge of the crack
5
IPC 2020
© TEAM, Inc. All rights reserved.
Type B Welded Sleeve Analysis
• Pipeline pressure at time of installation varied:– Zero pressure, 20% & 50%
reduction from MOP (72% yield)
• Solid curves show K after sleeve applied at reduced pressure and then pressure increased to MOP
• Installation pressure has significant impact on K & fatigue life
• Consideration of the degree of bonding at the crack opening has practical significance
6
IPC 2020
© TEAM, Inc. All rights reserved.
Composite Repair to Pipeline Cracking
• Tests completed by Sheets et al have measured fatigue life extension of cracked pipes with composite repairs– Work reported at PPIM last year on cracks in seam welds of LF-ERW pipe
– Scatter in results was large and variation in performance from base pipe was not isolated
– However, trends matched expected performance
• Life extension can be achieved– Crack growth slowed, but not stopped
7
© TEAM, Inc. All rights reserved.
Repair of Mechanical Damage
• 15% depth dents created on plane pipe, girth welds and seam welds– Re-rounded under pressure to ~6% diameter
• Tested with and without repairs
Tested as part of funded PRCI programme
Dent Location
Cycles to Failure, Unrepaired
Cycles Survived with repair
Seam Weld 6,205
All repairs survived
261,742 cycles
Seam Weld 7,018Plain Pipe 10,163Plain Pipe 10,334Girth Weld 7,023Girth Weld 24,996
© TEAM, Inc. All rights reserved.
Repair of Cracking
9
UK Gas Distribution in collaboration with DNV GL
• Crack-like features were found on an 18” OD, above ground, natural gas pipeline elbow during routine repainting– The line had been in service for 53 years
– Original wall 7.92mm (0.312”)
– Grade B, SMYS 241Nmm-2 (X35)
– 16bar (230psi) typical operating pressure
• Cracks probably caused by application of too much heat during field bending
• Crack depth could not be measured so fracture mechanics used to define maximum crack size based on hydrotest and service loading
© TEAM, Inc. All rights reserved.
Repair of Cracking
10
UK Gas Distribution
• Principal strains, operating pressureand air temperature were collected hourly– One month prior to installation of the repair
– 11 months after installation of the repair
• Initial monitoring data fed into model to evaluate stress reduction provided by repair
• Line pressure reduced to ~12.5% of operating pressure for installation AND cure– To maximise load transfer to the repair
• The application of the repair increased the pipe service life to 276 years, so acceptable for long term performance.
© TEAM, Inc. All rights reserved.
Repair of Mechanical Damage
• Local rock dent faired back to original shape of line using high stiffness epoxy putty to ensure effective load transfer
• Repair applied to control deformation in dent and extend fatigue life
• Life assessed based on pressure in pipe at time of installation– Effects stress level and stress range in steel and therefore the
fatigue life
– Calculations based on methods in API 579
Case Study - Transmission Line Example
© TEAM, Inc. All rights reserved.
Repair of Geometrical Defects
• Extended length on bend affected– Some of the defects were interacting
• Assessment of features completed by calculating the fatigue life using FEA
• Repair thickness estemated based on industry defect assessment codes– Known to have limited accuracy
• Fatigue life recalculated by re-running the FEA model including the repair and considering the pressure at time of installation to verify performance
• TEAM provide single point of responsibility for all steps
Case Study - Wrinkle Bend
© TEAM, Inc. All rights reserved.
Summary
• Conventional metal loss rules can not be used when evaluating repairs to mechanical damage and crack-like features
• Advanced engineering analysis validated through empirical testing ensures solution is reliable
• Key variables in repair design– Damage geometry
– Installation Pressure
– Assumptions around bold performance
– Modulus of filler material
– Repair sleeve mechanical properties
• TEAM’s unique in-house capabilities in inspection, advanced engineering and repair materials/installation remove hand-offs and ensure the integrity of our client’s most critical assets
• Announcing TEAM’s new pipeline integrity app – advanced workflow and visibility for pipeline integrity programs
13
Turney Solutions for Critical Assets
Thank You
Questions?
