LIFE EXTENTION

A CHANGE OF HABITS

The promise of Extended Life

How to extend life

• To extend life we first need to determine how lifespan is defined. – What determines

degradation? – When is a tank ‘aged’? – What do we find is still

acceptable? When do we need to start worrying?

Analysing our database of tankassessments we found no

apparant relation between year of construction and

remaining life.

We also assessed tanks of 15- yrs that required urgent

maintenance

We assessed tanks of 50+ yrs that where in perfect

condition

1325 2017

Planar tilt

What are you realy after?

Is the goal actualy ‘life extension?’

Or maybe ‘effective life’?

Maintenance cost €50.000,- and reopen in 5 years.

Maintenance cost €200.000,- and reopen in 20 years.

Timeline

Sequence of events

Tank is taken out of service

Inspections are carried out

Repairs are carried out

Tank is taken into service

Tank Assessment

Result: Lifespan x

Determine tank strategy & required lifespan

Determine engineering framework

Tank is taken out of service

Inspections are carried out Quick assessment & scenario selection

Repairs are carried out

Reorganise other assets to align with this result!!

Tank Assessment

Tank is taken into service

Result: tank has desired lifespan

Engineering

Tank turnaround

Engineering

RBI & Tank Integrity Management

• This formula is called ‘RBI’

• Determining risk requires a framework defined by the tankowner

– How ‘rusty’ is a ‘rusty shell’? – How toxic/dangerous is naphta? – How dangerous is a leak in a floating roof? – What level of risk is acceptable? – Etc.

• When setup correctly this is relatively quickly done.

• It takes about 5% of the time required.

• 95% of the work is determining the remaining lifetime

• This also requires a framework defined by the tankowner.

– Which components are to be assessed? And how? Which not? Why not?

– What remaining thickness is used for calculations? Minimal? Average? Weighed average? Etc.

– How is pit-depth analysed? – What do you do when a rejection

limit is reached? How are control measures applied?

– The methodology determines how inspections & NDT need to be performed (and what not!)

IMPORTANT: Determining an RLT is also possible without or limited inspection data (consequently it could be shorter to allow for uncertainties).

Next Inspection (NI) = Risk factor (K) x Remaining life (RLT) Example: roofleg-holder.

Often measured standard. Why?

• Critical component? • What is the dominant

degradation mechanism? • How can that be

monitored/inspected? • How thin/weak may it get

before action is required? • What actions are possible?

Is this NI executable? Planning/HSE/Finance/…

Is this NI feasible? What if Edge Settlement is 95% near reject and

the NI is 20 yrs? UT spot measurement

Auditable, Traceble & Securing

Sequence of events

Tank is taken out of service

Inspections are carried out

Repairs are carried out

Tanks is taken into service

Tank Assessment

Result: Lifespan x

Determine tank strategy & required lifespan

Determine engineering framework

Tank is taken out of service

Inspections are carried out Quick assessment & scenario selection

Repairs are carried out

Reorganise other assets to align with this result!!

Tank Assessment

Tank is taken into service

Result: tank has desired lifespan

Engineering

Tank turnaround

Engineering

In the long run this is cheaper and the asset lives longer

Actual example of a business case.

### numbers: Commercial volume: 1,69 mln m3 (according to max. filling height) Actual volume: 1,90 mln m3 (based on total height) Current average total cost of

maintenance: € 13 mln

Assumed replacement value: € 250 /m3 Total replacement value: € 421,5 mln - € 474,4 mln Resulting ### benchmark:

2,74% - 3,08%

Hardest part is to stay here!

Avoid the jo-jo!

• The hardest part is permanently change habits – Following MOC’s – Process product-changes – Process new insights – Reserve time for upkeep! – Following procedures – ….etc

• Avoid adminstration syndrome! – NDT portal – Computer aid – Alerts – Repair-scenarios

Weldoverlay / patchplate Replace plate

Not tables but visualisation of UT readings Floorscan results do not correlate

with UT survey -> verify

Turn data into information

• Measuring is knowing… if you know what you are measuring!!

• Meta analysis – Although thorough

tankassessment, tank started leaking anyway..

– How can that happen?

Inspection not 100% reliable: • Floor is not 100% inspected • PoD of Floorscan is ~50%-85% • Location not always clear Repair not 100% reliable: • Non detected pitting is not marked

for repair • Repair can be overlooked • Repairs can be executed badly Analysis • There can be more/severe

degradations than reported • Degradations can be expected to

be repaired but in fact are not

Chance of leak within operational period

Meta-analysis • Perform a statement on the general

condition of the tankfloor.

• With that assume a corresponding chance that there could be threatening degradation left.

• Add a risk label containing mitigating actions like:

• Increased survey on repairs • Higher safety margings • Limited operational periods • …

52%

29%

12%

7%

membrane pitting

sump pitting

combination

else

Essence of Tank Integrity Management (or ‘RBI’) is:

Determining a maintenance & inspection strategy for a tank for a specific periode in which various disciplines are represented.

It is not determining a simple OK/NOK or an inspection interval

Is it worth it?

Tank Integrity Management is about:

• Autditiable, responsible operation – responsible:

• License to operate • Compliance tankowner (where do we

spend our money on and why?) – Auditable:

• A transparant system that enables to show that above responsibilty with sufficient larity (tracebility)

• Clear and uniform to those who work with it (no miscommunication about what to do)

• Unknown Integrity Risks!

• Forecast in required finances en workload

• Comply to logistic demand (what needs to be done to keep a tank in operation for another X years)

• Control means influence

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Integrity Risks

Thank you for your attention