Risk Based Inspection presentation for storage terminals.

1. Specialsists in Tank Integrity
& Compliance
J.F. Rosendaal & R.H. Algra
RBI presentation

2. Overview
• Asset Integrity Basics
• Analysis example
• Specific cases
2 Specialists in Tank Integrity & Compliance

3. Asset Integrity Basics
Component
breakdown
Critical structural parts
• Membrane plates
• Roof support structure
• Nozzles
• Foundation
• Roofplates
• Etc.
Critical functional parts
• Pumps
• Valves
• Roof seal
• Mixers
• Overflow alarm
• Etc.
Specialists in Tank 3 Integrity & Compliance

4. Asset Integrity Basics
Component
breakdown
Dominant
degradation
mechanisms
4
Membrane
plates
Foundation
General thinning of
plates? (p.e. wear & tear)
Local soil side corrosion?
(p.e. water or chlorides)
Local topside corrosion like
pitting? (p.e. product)
Bacterial corrosion?
Other?
Edge Settlement?
Even settlement?
Differential Settlement?
Planar tilt?
Sagging?
Other?
Specialists in Tank Integrity & Compliance

5. Asset Integrity Basics
Component
breakdown
Dominant
degradation
mechanisms
Correspondin
g Inspection
5
plan
Is the inspection/NDT actually adequate to monitor the
degradation?
Example floorplate:
Degradation mechanism: local soil-side corrosion.
Wrong inspection: Spot-check UT from product-side
Recommended inspection: Floorscan
Does the plan cover sufficient area / is sufficiently detailed?
Example tankshell:
Preferrent locations: liquid-to-vapour corrosion,
increased corrosion at sun-side of tankshell
Wrong inspection: Spot-check UT along stairs
Recommended inspection: UT magnetic crawler
UT points
Degradations mechanisms that are not present (prevented)
not need NDT!
Example floorplates:
Foundation sufficiently high; floor-foundation transition adequatly sealed for
rainwater; no soil contaminations (chloride), underside coated, etc.
-> soil-side corrosion cannot occur -> Floorscan not required.
Specialists in Tank Integrity & Compliance

6. Asset Integrity Basics
Component
breakdown
Dominant
degradation
mechanisms
Correspondin
g Inspection
plan
Analysis &
Secure in RB-IT
6 Specialists in Tank Integrity & Compliance

7. Analysis using RB-IT 360
Component
breakdown
Dominant
degradation
mechanisms
Correspondin
g Inspection
7
plan
Analysis &
Secure in RB-IT
Is covered in the corporate methodology
(modelomschrijving RBI)
How to analyse, assess and what to do step by
step is covered in detail in the corporate
methodology (modelomschrijving RBI)
What remains to be done: Perform analysis, discuss
results and formulate plan for inspection &
maintenance
Specialists in Tank Integrity & Compliance

8. Analysis example: Remaining Lifetime calculation
Structural
strength
8
Remaining lifetime assessment specific component
Historic inspection & repairs
Data
Analysis
Acceptable
Rejected Rejection limit
Time
Remaining
lifetime
Today
Weighed extrapolation based
on anticipated service
Specialists in Tank Integrity & Compliance

9. Analysis example: Remaining Lifetime calculation
Structural
strength
IMPORTANT FACTS:
Trending historic data is not just connecting dots!!! A reliable degradation
rate is essential for the assessment and requires skills & experience.
The objective of RBI is to determine inspection periods based on risks. If
there is less historic data this will result in a higher risk (condition is
unclear) and will automatically result in earlier inspections. RBI is
possible without or with limited historic data.
9
Remaining lifetime assessment specific component
Historic inspection & repairs
Data
Analysis
Acceptable
Rejected Rejection limit
Time
Remaining
lifetime
Today
Weighed extrapolation based
on anticipated service
Specialists in Tank Integrity & Compliance

10. Analysis example: Determine inspection interval (RBI)
10
Acceptable
Rejected
Risk assessment
Structural
strength
Time
Remaining lifetime assessment
+ RBI What to do?
Year of
next
inspection
Remaining
lifetime
Today
How much does it cost?
Specialists in Tank Integrity & Compliance

11. Dominant failure modes
Specialists in Tank 11 Integrity & Compliance

12. Trending (1)
• Is trending analysis carried out reliably?
Reliable trending needs contect, not just measurements.
Specialists in Tank 12 Integrity & Compliance

13. • 1960: tank built for storage of low sulphur diesel
• 1995: service change for storage gas condensate. The tank pad was renovated and a
leak detection foil installed, resulting in a 10-year fixed inspection term.
• 2005: Component inspected. Lots of rust observed on the tankfloor, remaining WT =
4,2 mm. Pits more than 2 mm are repaired by welding.
Question: Is the trending reliable?
Trending (2)
New construction
Inspection
rejection
1960 1995 2005
8mm
4,2m
m
2,5m
m
2015
Long inspection
term but is this
adivsable?
theory
High risk through
uncertainty
13 Specialists in Tank Integrity & Compliance

14. In general
• Older and solely time-based regimes are usely insufficiently
covering the various degradations that are dominantly active
on the tank.
• This leads to an increased risk on incidents/unforeseen
events.
• Continuation of that procedure is expected to result in an
increase of incidents and an increase of the required
maintenance budget (‘fire fighting’).
• Risks can be controlled by a solid asset integrity approach. In
time this will result in a decrease of incidents and a decrease
of the maintenance budget.
• RBI is about ‘operating responsibly’
Specialists in Tank 14 Integrity & Compliance

15. EEMUA offstream inspectie list
• Visual external inspection following predefined checklist
• Visual internal inspection following predefined checklist
• Floorscan
• 5 points per plate UT measurements tankfloor
• Sagging
• Edge settlement
• Differential settlement
• Scheefstand
• Bulges and ripples in tankfloor
• Annular toe thickness measurement
• A-height cornerweld
• UT crawler inspection tankshell
• Manual UT grid tankroof
• Manual UT nozzles + internal piping
• Manual UT pontoons (bij EFR)
All critical components need to be
checked for leading degradation
mechanisms.
15 Specialists in Tank Integrity & Compliance

16. Closing the loop (PDCA)
Component
breakdown
Dominant
degradation
mechanisms
Corresponding
Inspection plan
Analysis &
Secure in RB-IT
16
Maintenance
and inspection
Specialists in Tank Integrity & Compliance

17. Closing the loop (PDCA)
Component
breakdown
Dominant
degradation
mechanisms
Corresponding
Inspection plan
Analysis &
Secure in RB-IT
17
Maintenance
and inspection
Specialists in Tank Integrity & Compliance

18. PGS-29 equipment
• RBI focuses on leakage or catastrophic failure
• RBI focuses on steel components
• RBI does not focus on functionality or
operability of tank equipment
• PGS-29 has further requirements on this issue
• These are adressed in the equipment module
18 Specialists in Tank Integrity & Compliance

19. Equipment tool
19 Specialists in Tank Integrity & Compliance

20. Insulated tanks
Component =
insulated Shell
Degmech =
20
CUI
CUI inspection
plan
Analysis &
secure in RBIT
Suspect areas:
•Remove insulation
Assess depth of damage using UT, pit gauge, profile comb
Use L-criterium to calculate equivalent wallthickness
Carry out fitness for service assessment
Define maintenance actions if needed
API 581: Influencing factors assessment
• Operating temp
• Coating condition
• Coating age
• Cladding condition
• INCOtest is considered reliable above 8
Insulation type
mm remaining wallthickness with a small
lift-off and no chicken wire in insulation.
• Environment
• External steam coil
• Crawler inspection can be used on the
inside of the tank.
• Thermography for hotspots.
• Visual external for condition of insulation
Specialists in Tank Integrity & Compliance

21. Riveted tanks
Component =
rivet rows
Degmech =
creep and
corrosion
Inspection
21
plan
Analysis &
secure in RBIT
• Visual inspection for bleeding
and corrosion
Specialists in Tank Integrity & Compliance

22. Product updater module
Component =
floor, shell,
roof, nozzles
Degmech =
pitting and
gencorr
Inspection
22
plan
Analysis &
secure in RBIT
Specialists in Tank Integrity & Compliance

23. RVS tanks
Component =
floor, shell,
roof, nozzles
Degmech =
non-existent
Inspection
23
plan
Analysis &
secure in RBIT
Inspection plan:
•Essence is to confirm that no degradation is taking place
•Scope is very small
•Visual shoud be sufficient
However: product stored should be fit for the tank material
Specialists in Tank Integrity & Compliance

24. Wind Girders
Component =
2244
Shell
Degmech =
Buckling due
to windload
Inspection
plan
Analysis &
secure in RBIT
Mean values
for wallthickness
Specialists in Tank Integrity & Compliance

25. Steam spirals
• Sometimes classified as pressure vessel and
sometimes as pipe
• When classified as pressure vessel a steam
spiral falls often in a legal inspection regime
• When classified as pipe there is normally no
legal inspection regime
• If inspection is mandatory, normally a
pressure test is conducted every 6 years
25 Specialists in Tank Integrity & Compliance

26. Underground bullit tanks
EEMUA 190
•Soil settlement monitoring
•Types of foundation
•Inspection requirements
•Design
26 Specialists in Tank Integrity & Compliance