ir tripod-beta · tripod-beta incident investigation and analysis cement technology magazine:...

Betashow.ppt 1999 Shell International Exploration and Production B.V.

Tripod-BETATripod-BETAIncident Investigation and Analysis

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cement technology magazine: 021-22883306, 22861343

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Incidents are an indicator to improve our performance

Understanding Understanding whatwhathappened and happened and whywhy

enables us to enables us to improve our improve our

businessbusiness



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Structure of the HSE Management SystemLeadership and Commitment

Policy and Strategic Objectives

Management Review

Corrective Action & Improvement

Audit

Organisation, ResponsibilitiesResources, Standards & Doc.


Tripod Beta

Monitoring

Planning & Procedures

Hazard and Effects Management

Implementation

CorrectiveAction



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What is Tripod-BETA ?What is Tripod-BETA ?

A methodology for incident analysis during an investigation ...

combining concepts of hazard managementand ...

the Tripod theory of accident causation.



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How does Tripod-BETA work ?How does Tripod-BETA work ?

The incident facts are built into a tree diagram showing ...

- What happened ...

- What hazard management elements failedand

- Why each element failed.



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What does the software do ?What does the software do ?

The software:

lStores investigation facts

lProvides tree-building graphics

lChecks the implicit tree logic

lAttaches data to tree elements

lAssembles attached data into a draft report.



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How does the tree work ?How does the tree work ?

Let’s walk through a simple incident

introducing the terminology

and logic

that underpins Tripod-BETA



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The IncidentThe Incident

lLocation: an offshore platform

l Incident: an operative coming off shift slips and falls in the shower room

lConsequence: he hurts his back and is off work

l In the past three months there have been two similar incidents



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Initial FindingsInitial Findings

lThe incident occurred at 1820 hours

lThe operative slipped on the wet floor

lCleaning staff are supposed to keep the shower room floor dry



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Starting a Tripod TreeStarting a Tripod Tree

We start by identifying:

lAn EVENT - where a hazard and a target get together

lA TARGET - a person or an object that was harmed

lA HAZARD - the thing that did the harm



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The Hazard, Event, Target TrioThe Hazard, Event, Target Trio

They are shown in a Tripod tree like this:

Hazard

Event

Target



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Hazard, Event & TargetHazard, Event & Target

In this incident:

The HAZARD is: Wet floor (slipping hazard)

The EVENT is : Operative falls in shower room

The TARGET is : Operative



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HET DiagramHET Diagram

The Hazard,

Wet floor (slipping hazard)

Event

Target



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The Hazard, acting on the Target,


Event

Operative



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The Hazard, acting on the Target, resulted in the Event


Operative falls in shower room

Operative



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Is the investigation complete ?Is the investigation complete ?

lDoes this show full understanding ?

Finding: The man must have been careless

Recommendation: He should take more care on a wet floor

lOr is there something more ?



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Was the incident preventable ?Was the incident preventable ?

lWe know that a hazard management measure was in place

lCleaning staff were assigned to keep the floor dry

lThat ‘barrier’ to the incident failed



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Failed BarrierFailed Barrier

The barrier should have controlled the hazard

Hazard

Event

Target

FailedBarrier



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Incident MechanismIncident Mechanism

The incident mechanism looks like this:



Operative

Floordrying



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Further InvestigationFurther Investigation

What caused the barrier to fail ?

lThe cleaner could not keep the floor dry ...

lbecause the shower room was always congested between 1800 and 1900 hrs



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Active FailureActive Failure

An Active Failure defeated the barrier



Operative

Floor drying

ActiveFailure

Active Failure



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Active FailureActive Failure

An Active Failure defeated the barrier



Operative

Floor drying

Cleaner unable to keep floor dry

Active Failure



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End of Investigation ?End of Investigation ?

l Is this the end of the investigation ?

Finding: The cleaner was incompetent

Recommendation: Cleaner should be replaced or retrained

lOr is there still something more ?



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Further InvestigationFurther Investigation

lWe know that congestion was a factor that prompted the active failure

lTelephones are only available for private calls up till 1900 hrs

lThe congestion is caused by day shift crew hurrying to call home



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The Full PictureThe Full Picture

Now we have the full picture:

lThe congestion is a ‘Precondition’ that influenced the cleaner’s task

lRestriction on telephones is a ‘Latent Failure’ that created the precondition



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PreconditionPrecondition



Operative

Floor drying

Precondition

Precondition


Active Failure



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PreconditionPrecondition



Operative

Floor drying

Congestion1800 - 1900 hrs

Precondition


Active Failure



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Latent FailureLatent Failure



Operative

Floor drying

Latent Failure

Latent Failure Congestion1800 - 1900 hrs

Precondition


Active Failure



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Latent FailureLatent Failure



Operative

Floor drying

Latent Failure

Restriction onprivate phone calls

Congestion1800 - 1900 hrs

Precondition


Active Failure



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RecommendationsRecommendations

Action items should address:

lThe failed barrier ...to restore safe conditions on a temporary basis(provide extra cleaner between 1800 and 1900)

lThe latent failure ... to remove the underlying cause(extend the availability of shore telephone)



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Complex EventsComplex Events

lThat was a simple example

lThe Tripod-BETA methodology can also be applied in complex events



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Identify the prime Event,

Fire



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Identify the prime Event, the Hazard,

Ignition

Fire



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Identify the prime Event, the Hazard, and Target.

Flammable Gas Cloud

Ignition

Fire



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If, say, the target was created by a prior event

Flammable GasCloud

Ignition

Fire



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Identify the hazard ...

Event & Target

DroppedObject

Flammable GasCloud

Ignition

Fire



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and target for that event.

Gas Line

DroppedObject

Flammable GasCloud

Ignition

Fire



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Similarly, if a consequential event happens ...

Gas Line

DroppedObject

Flammable GasCloud

Ignition

Damage to Platform

Fire



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because the prime event created a new hazard,

Gas Line

DroppedObject

Flammable GasCloud

Ignition

Damage to Platform

Fire



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identify the target for the new event.

Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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Identify failed ‘barriers’,

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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and missing ones ...

MissingBarrier

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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including multiple failures ...

FailedBarrier

FailedBarrier

MissingBarrier

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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on each relevant ‘trajectory’ ...

MissingBarrier

FailedBarrier

FailedBarrier

FailedBarrier

MissingBarrier

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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until the Incident Mechanism is complete.

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

FailedBarrier

MissingBarrier

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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Complex EventsComplex EventsShow the Active Failure for each barrier, ...

ActiveFailure

Active Failure

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

FailedBarrier

MissingBarrier

FailedBarrier Fire

IgnitionSource

Gas Line

Flammable Gas Cloud

Dropped Object

Platform

Damage to Platform



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Complex EventsComplex Eventsthe Precondition(s) promoting each active

failure, ...

FailedBarrier

FailedBarrier

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

Event

Event & Hazard

Hazard

Target

Target

ActiveFailure

Active Failure

Precondition

Precondition

Event & Target

HazardMissingBarrier



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Complex EventsComplex Eventsand the Latent Failure behind each

precondition.

FailedBarrier

FailedBarrier

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

Event

Event & Hazard

Hazard

Target

Target

Latent Failure

LatentFailure

ActiveFailure

Active Failure

Precondition

Precondition

Event & Target




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Complex EventsComplex EventslComplete a ‘Tripod path’ for each barrier.

FailedBarrier

FailedBarrier

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

Event

Event & Hazard

Hazard

Target

Target

Latent Failure

LatentFailure

ActiveFailure

Active Failure

Precondition

Precondition

Latent Failure

LatentFailure

ActiveFailure

Active Failure

Precondition

Precondition

Event & Target




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The completed Tripod-BETA treeThe completed Tripod-BETA tree

FailedControl

FailedBarrier

MissingBarrier

MissingBarrier

FailedBarrier

FailedBarrier

Event

Event & Hazard

Hazard

Target

Target

Latent Failure

LatentFailure

Latent Failure

LatentFailure

Latent Failure

LatentFailure

ActiveFailure

Active Failure

Precondition

Precondition

Latent Failure

LatentFailure

ActiveFailure

Active Failure

Precondition

Precondition

Latent Failure

LatentFailure

ActiveFailure

Active FailurePrecondition

Precondition

Latent Failure

LatentFailure Precondition

Precondition

Event & Target

Hazard

Latent Failure

LatentFailure

MissingBarrier



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Structure of the HSE Management SystemLeadership and Commitment

Policy and Strategic Objectives

Management Review


Audit

Organisation, ResponsibilitiesResources, Standards & Doc.


Tripod Beta

Monitoring

Planning & Procedures

Hazard and Effects Management

Implementation

CorrectiveAction



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ology

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Long term action to reduce latent failuresLong term action to reduce latent failures

latent failure

latent failure

precondition

precondition

active failure

Replace the failed barrierReplace the failed barrier

Corrective Actions



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Corrective Actions

l If the barriers have not been replaced you should question why operations have restarted

lActions to replace barriers are normally on site

lLatent Failures are deep seated do not expect to remove them tomorrow

lAction to tackle latent failures are normally at management level



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Tripod-BETATripod-BETA

lBrings a structure to investigation

lHelps distinguish relevent facts

lMakes causes and effects explicit

lEncourages team discussion

lReduces the report writing task



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