Uncertainty Risk has no memory
Chris Venn
© Chevron 2005
DOC ID
What makes a Hazard a Risk?
„ Identify the Hazards in the following image:
„ What is the risk from these hazards when on another
hole?
© Chevron 2005
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So what is Risk?
Risk= Likelihood x Outcome x Importance…
We simply ask four questions…
„ What can go wrong
„ How often
„ How bad
„ So what…
© Chevron 2005
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Predicting How often
6
What
are the possible outcomes from spinning a coin
„ 5Heads
4
„ Tails
3
„ Edge
2
1
„ Lost
0
Each table
has 5 coins…spin each coin 5 times to get 25 results.
1 2
3 4
5 6
7 8
Write them down
9
10 1
1
12
13
14
5
1
This Chart shows the output
16 7
1
21
from the Offshore Involvement day.
Expected variability is shown in Heads and
tails, the Edge’s are uncertain
„ What will the next spin be?
© Chevron 2005
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22
23
Ed
ge
24
25
He
ads
Variability and Uncertainty
The chance of a lottery win is 1 in 14 million
About the same chance of me dropping dead in
the next 15 minutes…
…the lottery is predictable, my mortality is uncertain
(I hope)
Can you confidently predict missing a bunker based
on your last round of golf?
Can Tiger Woods?
© Chevron 2005
DOC ID
Past as a measure of the future
During German air raids on Moscow a professor of
statistics always avoided the air shelter
“…there are 7 million people in Moscow, why should I expect
them to hit me?”
One night he appeared… when asked why he replied
“ There are 7 million people in Moscow and one
Elephant...Last night they got the elephant”
Are major accidents predictably variable or
Uncertain?
Is it the lottery or my life?
Taken from: Bernstein, Peter L. Against the Gods – John Wiley & Sons ISBN 0 471 295639
© Chevron 2005
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What is keeping us safe?
Do we allow a design where a single failure is certain
to cause a major accident?
What are our barriers? How many do we need?
OGP defines a barrier as a functional grouping of
safeguards and controls selected to prevent the
realization of a hazard.
We know them as Safety Critical Elements
© Chevron 2005
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Start with Basis of Design
Automatic
Controls
e.g. ESD
Operator
Action
Ignition
Control
Major Accident
Process
Boundary
Beyond Design Basis© Chevron 2005
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Outer
Layer e.g.
PSV or
HIPS
Emergency
response
Residual Risk from Failure to Control
Keeping us Safe -Integrity Management
Operating
Envelope Model
STRUCTURAL &
MARINE
SYSTEMS
PROCESS
CONTAINMENT
Barrier Model
SAFEGUARDING
SYSTEMS
IGNITION
CONTROL
Integrity Model
ACTIVE
PROTECTION
SYSTEMS
EMERGENCY
RESPONSE &
RECOVERY
© Chevron 2005
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Chain of Events
STRUCTURAL &
MARINE
SYSTEMS
PROCESS
CONTAINMENT
SAFEGUARDING
SYSTEMS
IGNITION
CONTROL
ACTIVE
PROTECTION
SYSTEMS
© Chevron 2005
How do we break the chain?
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EMERGENCY
RESPONSE &
RECOVERY
How are we doing?
2006/2007 – HSE Data:
„ Nearly 30,000 offshore workers
„ About 200 installations
„ 2 fatal, 39 major injuries
„ 4 “major” hydrocarbon releases – each capable of quickly escalating or
reaching the TR.
„ 70 “significant” hydrocarbon releases – each capable of causing
serious injury or fatality, „ 99 minor hydrocarbon releases
„ 20 non-hydrocarbon dangerous releases
„ 41 non-hydrocarbon fires & explosions
„ 6 reportable ship impacts with installations
….Room to Improve
© Chevron 2005
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What is keeping you safe?
Hydrocarbon Boundary…
„ Who has witnessed a small or significant leak in the last year?
Low ignition probability…
„ Who has backlog on EX maintenance and inspection?
Detection
„ How many of you have defective or overridden detectors?
Deluge
„ Who has had a blocked deluge nozzle or furred pipework?
TR
„ How many of your TR HVACs meet their performance standards?
EE&R
„ How many of you have backlog or deferral on davit maintenance?
© Chevron 2005
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Who put their hand up more than once?