Improving Safety – Reducing Hydrocarbon Releases
Pipework Vibration / Fatigue Awareness
Stuart McGregor
Senior Project Engineer
Date: 30th June 2010
Department: Plant Integrity
Jeremie Neillo
Business Development Manager
Purpose
Background
• Hydrocarbon releases are a major risk offshore
• Accounts for 33% of all dangerous occurrences reported to HSE
• A significant proportion are caused by vibration fatigue
• This is avoidable
Purpose
To give you an understanding of:
• What vibration fatigue is
• Why you should consider it
• What you can do about it
Page 1
Introduction
Doosan Babcock Energy
• Have over 110 years experience in the energy sector
• Have a long history for designing, supplying and constructing efficient
coal fired power plant
• Are a leading engineering services provider for the power and energy
sector, including offshore
• Worked with the offshore industry to develop the AVIFF (avoidance of
vibration fatigue failure) Guidelines, which are regarded as the
benchmark for managing pipework vibration fatigue
• Have significant experience of identifying and resolving vibration issues
offshore - reducing HC releases
Page 2
Agenda
• What role does vibration play in pipework failure
• What are the benefits of good vibration awareness
• What is the solution
• Worker involvement, what role do you play
• The future – how do we keep moving forward
Page 3
What is vibration…
Vibration
• Small movements
rapidly to and fro
• Oscillations
Page 4
What is fatigue…
Fatigue
• Progressive and localized
structural damage that occurs
when a material is subjected
to cyclic loading
• Can lead to failure
Page 5
Is Piping Vibration really an issue…
• What type of vibration failures can occur
• Is this a real threat to us
Page 6
Small Bore Connections (SBC’s)
• SBC are at significant risk
from vibration fatigue
• Potential for failure at the
welded connection to main
line
• Greatest risk on thin walled
pipework
• What does high risk look like
Page 7
Small Bore Connections
Page 8
Small Bore Connections – With Support Brackets
Page 9
Failure at welds in main lines
• Designed to recognised piping
code by Competent
Engineers
• 6” Flare Pipework Failed in
service due to Turbulent
Excitation
• Pipework was observed to be
vibrating (at Low Frequency)
but no action was taken
• When may this be a particular
risk
Page 10
Fretting
• Pipework vibration can result in
Fretting
• Fretting can occur when there is
relative motion between 2
surfaces
• Potential for loss of containment
• What fretting risks should we
look out for
Page 11
Benefits of Vibration Awareness – Safety & Environmental
Significant progress made by industry:
• From early 2000’s to today, HC releases in the North Sea caused by
vibration fatigue have nearly halved
• Some operators have made very significant progress, some have made
minimal progress
Major KPI by HSE & Insurance industry
Page 12
Benefits of Vibration Awareness – Case Study – North Sea Platform
Before - 2004
After - 2005
• 10 off HC releases in 2004
• Full vibration review of platform
• 5 off were vibration related
• Modifications to reduce rectify identified risks
• At least 2 vibration release resulted in
• Ongoing maintenance & healthcare plan in
controlled shut down
place
• 1 off was a 10 day shut down for major
• Total cost including modification approx £1M
weld repairs
• 10 off vibration failures since 2005
• Minimal proactive management of vibration • No controlled shut downs
fatigue
• Potential for major accident to occur
Status 2010
• Risks known and being proactively managed
Status - 2004
• Minimal impact upon safety and productivity
• Major unknown and unmanaged risks
• Risks ALARP – As Low As Reasonably
• Significant impact upon safety and
Practicable
productivity
• Atleast 10 days lost production (£40-60M)
Page 13
Solutions – The Engineers Role
• Follow AVIFF guidance to minimise risks
– Initial surveys (office and site based)
– Resolve concerns
– Ongoing monitoring (annual / following major change)
• Consider Vibration
– At design stage
– Prior to changes / updates
•Process change
•New plant equipment
•Pipework changes (Carbon steel to Super-Duplex)
Page 14
Solutions – What Role Can you Play…
• Would would you do if…..
Page 15
Solutions – What Role Can you Play…
Keep your eyes and ears open
• Pipework vibrating
• Leaks / drips
• Noise, especially tonal
• Changes from yesterday / last
trip
Don’t assume someone else has
reported the concern
You can be the eyes and ears of
the safety / Asset integrity team
Page 16
Look Out For Clamps – Maintenance & Inspection
• Example of critical clamp not been re-instated correctly after
intervention work on line
Page 17
Solutions – What Role Can you Play…
Look out for…..
• Small Bore Connections
vibrating
• Pipework vibrating
• Fretting risks
• Small leaks / drips
• Noise
• Changes since yesterday /
last visit
• Clamps / brackets refitted
correctly
Page 18
The Future – How Do We Keep Moving Forward
•
•
•
•
•
Be Proactive
Follow and apply AVIFF guidelines
Implement regular health checks for vibration fatigue
Consider vibration before major changes
Consider vibration at design stage
Keep your eyes and ears open
Report concerns
Page 19
Questions
Stuart McGregor
Senior Project Engineer
Jeremie Neillo
Business Development Manager
Tel: 01224 224 316
Email: smcgregor@doosanbabcock.com
Tel: 01224 224 315
Email: jneillo@doosanbabcock.com
Page 20