CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Shell Global Solutions
SHELL RISK-BASED INSPECTION (S-RBI)
Basics & Related Approach
to Corrosion under Insulation (CUI)
Presented by:
Maarten Lorenz
Materials & Inspection Technology
Shell Research & Technology Centre,
Amsterdam, The Netherlands
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Shell Global Solutions Pacesetting Concept
PACESETTING
PROGRAM
sustained top 10%
performance for
more than 5 years
HSE PROGRAM
HYDRO CARBON MANAGEMENT
MERIT REVIEW
M
E
R
I
T
anufacturing
nhanced
eliability
mprovement
eam
ORGANISATION
MANAGEMENT OF ASSETS
Integrated versions of:
RISK AND
Reliability Centred Maintenace
RELIABILITY
Risk-Based Inspection
MANAGEMENT Instrumented protective functions
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
S-RBI in Relation to Risk & Reliability Management
RISK AND RELIABILITY MANAGEMENT (RRM):
RISK-BASED INSPECTION
-> optimised inspection plan
RELIABILITY CENTRED MAINTENANCE
-> cost effective maintenance plan
INSTRUMENTED PROTECTIVE FUNCTIONS
-> minimum design and testing requirements
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Why Apply Risk-Based Inspection ?
To move away from time based inspection governed by
minimum compliance with rules, regulations and standards
for inspection.
To apply a strategy of doing what is needed for safeguarding
integrity and improving reliability as well as availability of the
plant by planning and executing those inspections that are
needed.
Risk-Based Inspection may provide economic benefits:
reduce inspection scope, shorter shutdowns, longer run
length, fewer unplanned shutdowns.
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
RBI = TEAM EFFORT
CORROSION ENGINEER
PLANT INSPECTOR
MAINTENANCE ENGINEER
PROCESS TECHNOLOGIST
OPERATOR
AUTHORITY REPRESENTATIVE (on request)
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
S-RBI RELATED TOOLS
Maintenance Electronic
and Inspection Drawings
Database
(VISIO)
Corrosion
Control
Manual
Trending
Software
S-RBI (RRM)
Manual
S-RBI ANALYSIS
S-RBI (RRM)
Software
Statistical
Recipe Book
Degradation
Library
NDT
Handbook
FFP
Handbook
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
S-RBI Analysis based on Corrosion Loops
What is a Corrosion Loop?
A PRACTICAL WAY TO DESCRIBE, UNDERSTAND
AND CHECK DEGRADATION MECHANISMS IN A UNIT
part of the unit subjected to:
the
the
the
same process conditions
same failure mechanisms
same materials selection criteria
one operating window
control of degradations via
process control
values agreed by team
(boundary conditions for RBI)
deviation should be reported
CORROSION LOOP
12-E-102
Loop
2
12-E-101
Loop 1
12-D-101
Loop 3
12-K-101
1st stage
12-G-101
to burn pit
same process conditions
same degradation mechanisms
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
The Shell Risk-Based Inspection (S-RBI) Process
DEGRADATION MECHANISM
SUSCEPTIBILITY
CONSEQUENCE
Criticality
Matrix
INHERENT
CRITICALITY
REMNANT LIFE
HISTORY &
CONDITION
Interval
Matrix
CONFIDENCE
RATING
INSPECTION
PLAN
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Susceptibility To Failure
Determine potential degradation mechanisms for the Loop
For those degradation mechanisms, identify the StF per item
for each item since there can be differences in temperature etc.
For each item, analyse the different degradation mechanisms
separately since they may result in different failure modes
Different inspection techniques/intervals may be required
Monitoring scheme to be indicated for non-age realated
degradations
Shell Global Solutions
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Assessment of Consequence of Failure
Score Table on:
Economic consequences
Health & Safety consequences
Environmental consequences
Shell Global Solutions
10
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Susceptibility
S-RBI Criticality Matrix
HIGH
MEDIUM
LOW
NEGLIGIBLE
S-RBI
NEGLIGIBLE
NO INSPECTION
REVIEW ONLY
L
L
N
N
MH H
E
E
M MH H
E
L
M MH H
N
L
M MH
NEGLI LOW
GIBLE
MED
IUM
EXTREME
HIGH
HIGH EXTEN
SIVE
DETAILED
ANALYSIS
Consequences
LOW
RECTIFY
MEDIUM
MEDIUM-HIGH
INSPECTION PLAN
Shell Global Solutions
11
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Confidence Rating
indicator for confidence in forecast of degradation
rating - very low to very high reflects:
stability/predictability of degradation
number and quality of previous inspections
process stability
BETTER CONFIDENCE YIELDS
LONGER INSPECTION INTERVALS
Shell Global Solutions
12
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Maximum Inspection Interval
WALL
THICKNESS
INSPECTIONS
REMNANT LIFE
WT new
X
WT (min)
MAXIMUM INSPECTION
X
INTERVAL
MINIMUM ALLOWABLE THICKNESS
LIFETIME IN YEARS
Shell Global Solutions
13
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Corrosion Under Insulation
Shell Global Solutions
14
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
The S-RBI Process for CUI:
remnant life not available
CORROSION UNDER INSULATION
SUSCEPTIBILITY
CONSEQUENCE
Criticality
Matrix
INHERENT
CRITICALITY
REMNANT LIFE
HISTORY &
CONDITION
Strategy
Matrix
CONFIDENCE
RATING
MAINTENANCE
& INSPECTION
STRATEGY
Shell Global Solutions
15
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Determining CUI Susceptibility
Score Table on:
Operating Temperature
Initial Coating Status
Insulation Type
Wall Thickness & Surface Features
Internal Corrosion/Erosion Rate
External Coil/Steam Tracing
External Environment
Shell Global Solutions
16
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Determining CUI Consequence
Score Table on:
Economic consequences (including production loss!)
Health & Safety consequences
Environmental consequences
Shell Global Solutions
17
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Confidence Rating
An items criticality basically determines the
inspection/maintenance strategy to be applied.
Depending on how well the condition of an item is known, a
limited degree of conservatism/opportunism is applied in
choosing the inspection/maintenance strategy.
CUI Confidence Rating depends on:
cladding & insulation condition
number & quality of CUI inspections
knowledge of CUI promoting conditions
Shell Global Solutions
18
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
CUI Strategy Matrix for CS/Low Alloy Steel
CONFIDENCE RATING
CRITICALITY
EXTREME
HIGH
MEDIUM-HIGH
MEDIUM
LOW
NEGLIGIBLE
(review only)
VERY LOW LOW
MEDIUM
HIGH VERY HIGH
STRATEGY 0
STRATEGY 1
STRATEGY 1
STRATEGY
2
STRATEGY
2 STRATEGY
3
STRATEGY 3
STRATEGY 3
STRATEGY 4
NO INSPECTIONS
Shell Global Solutions
19
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
CUI Inspection/Maintenance Strategies
Effectively five strategies have been developed for the six
criticality levels.
The coverage and quality of the applied coating/paint may add
up to 8 years of CUI protection.
Inspection intervals start at the moment the coating/paint
protection has ended.
Inspection intervals are based on recommended maximum
timing.
Initial inspection actions always involve delagging.
Inspection results may lead to adjusting the strategy level.
Shell Global Solutions
20
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Inspection/Maintenance Strategys Loop
YES
Initial
Inspection
Corrective
Action
Significant
CUI?
NO
YES
Follow-up
Inspection
Corrective
Action
Significant
CUI ?
NO
Review
Strategy
(one cycle)
Shell Global Solutions
21
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Non-Intrusive Inspection Techniques for CUI?
Thermography ?
- finds wet spots, not CUI
- requires experienced operator
Pulsed Eddy Currents ?
- local measurement of wall thickness
- difficult to apply on complex geometries
- excellent for determining wall thickness
through corrosion products
(real-time) Radiography ? - suitable for small bore connections
- accessibility and safety issues
Guided-Waves ?
- screening technique to detect wall loss
- requires experienced operator
- only simple pipe geometries
Shell Global Solutions
22
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
CUI Inspection/Maintenance Plan:
requires pre-screening of the assets prior to application
(not applied to items with negligible susceptibility to CUI).
does not rely too much on non-intrusive inspection results
(screening inspection techniques used to indicate susceptible
areas).
is harmonised with the S-RBI methodology.
is also available for insulated stainless steel items
(CUI = Chloride Stress Corrosion Cracking).
does not eliminate CUI failures completely, but reduces the
effects of these failures to your business to a tolerable level.
Shell Global Solutions
23
CUI Conference 14-1-2004
2003 Shell Global Solutions International B.V.
Shell Global Solutions
SHELL RISK-BASED INSPECTION (S-RBI)
Basics & Related Approach
to Corrosion under Insulation (CUI)
- thank you for your attention ANY QUESTIONS OR REMARKS?
Presented by:
Maarten Lorenz
Materials & Inspection Technology
Shell Research & Technology Centre,
Amsterdam, The Netherlands
