Rio Pipeline Conference Presentation v5 (2)

8/11/2019 Rio Pipeline Conference Presentation v5 (2)

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A SET OF COMPTER BASED TOOLS

FOR IDENTIFYING AND

PREVENTING HUMAN ERROR IN

GAS PLANT OPERATIONS

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David EmbreyManaging Director

Human Reliability Associates LtdUK

Sara ZaedFounder

Zaed Engineering


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Overview

Why human factors is important to processsafety

What human factors analyses the regulators

are demanding in UK Safety Cases

Tools provided in the Human FactorsWorkbench software

How these tools are used together

Conclusions


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INCIDENT CAUSES IN A MULTINATIONALPETROCHEMICAL COMPANY

(450 Incidents)

, Weather,9, 9%

, Design,10, 10%

Eqpt.10%

, HumanError, 55,

55%

, Other, 16,16%


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Human error cannot be ignored.


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* COMAH Safety Report Assessment Manual, Appendix 4http://www.hse.gov.uk/comah/sram/index.htm

Identify potential for

human failures in

initiation, prevention,

and mitigation of major

incidents

Choose and justify the

balance of automatic

measures

Maintain and

continuously improve

by management

assurance loopImplement the

measures

- Design for people

- Prepare people todeliver to expectation

UK HEALTH & SAFETY EXECUTIVE HUMAN

FACTORS REQUIREMENTS FOR SAFETY CASES


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1. Identify and

prioritise tasks

3. Identify potential

human failures

4. Assess factors

that influence

failure probability

5. Implement

appropriate risk

management

strategies

2. Produce task

analyses

Repeat process

for other critical

tasks identified

in 1&2

Recommended

analysis process


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WHY ARE TOOLS NEEDED TO ASSESSHUMAN RELIABILITY?

Safety Regulators

increasingly requirehuman reliability to

be addressed inSafety Cases

Attention to human

factors issues canincrease safety,quality and efficiency

Human Factors

WorkbenchAn integrated set of tools

to address humanfactors analyses

Human error needs tobe addressed byboth proactive and

retrospectiveapproaches

Software support isrequired to ensurethat human factorsanalyses are rapid

and efficient


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WHAT HUMAN FACTORS TOOLS ARE INCLUDED INTHE HUMAN FACTORS WORKBENCH?

Tool Type Applications

Hierarchical task analysis(HTA)

Proactive Describing tasks, developingprocedures & training

Predictive human erroranalysis (PHEA)

Proactive Predicting possible error types, theiroutcomes & mitigating strategies

Sequential Timed EventPlotting (STEP)

Retrospective Analysing an accident sequence toidentify the people and hardwareinvolved

Measurement &Investigation Techniqueto Reduce Errors (MITRE)

Retrospective/ Proactive

Evaluating the factors influencing thelikelihood of errors to identifyspecific prevention strategies


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HIERARCHICAL TASK ANALYSIS STRUCTURE

Preconditions 0 Take propane tankout of service

Plan 0: Do in sequence

Subtask.. N

3.

Disconnect tanksuction

line

2. De-pressuretank suction

line

1. Isolate allflows to

tank

Plan 2: Do in sequence

2.3 Ask operationsleader for

permission todepressurise line

2.2 Fitpressuregauge toflare line

2.1 Connect LPG hosefrom water draw

valves to local pointin the flare line

Sub-taskstep 2.N

Overall taskobjective

Plan

(how subtasks are to be carried out)

Sub-tasks

Sub-task steps (examples only)

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ADVANTAGES OF HIERARCHICAL TASK ANALYSIS

Provides a logical breakdown of the taskstructure which plant operators find easy tounderstand

Level of detail of the description can be varieddepending on the level of insight required tomanage risks

Provides a good starting point for thedevelopment of procedures and job aids

Provides a good basis for human errorprediction in risk analysis

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PREDICTIVE HUMAN ERROR ANALYSIS

A predictive technique that identifies & evaluatesthe consequences of errors

Uses guidewords which are applied to each step

(or subtask) to prompt the analyst to think aboutpossible errors

Where errors with severe consequences areidentified, preventative strategies are specified

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EXAMPLES OF PHEA GUIDEWORDS

ACTIONERRORS

CHECKINGERRORS

INFORMATIONRETRIEVAL

ERRORS

COMMUNICATIONERRORS

Operationincomplete

Check incomplete Information notobtained

Information notcommunicated

Operationmistimed

Check mistimed Wrong informationobtained

Wrong informationcommunicated

Operation inwrong direction

Right check onwrong object

Information retrievalincomplete

Informationcommunication

incompleteRight operationon wrong object

Right check onwrong object

Informationincorrectlyinterpreted

Informationcommunicationunclear

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SEQUENTIALLY TIMED EVENTS PLOTTING (STEP)

Well established technique for documenting accidentevent sequences

Graphical representation

Gives an accident investigator a systematic & logicalprocess for describing what happened during anaccident sequence

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MITRE (MEASUREMENT AND INVESTIGATIONTECHNIQUE FOR REDUCING ERROR)

Develop a model of the factors that influenceerror for a particular class of activities, e.g.plant maintenance

Based on research and inputs from experienced

operators

Evaluate the quality of these factors in aparticular scenario

To predict the likelihood of error in a critical task

To evaluate the factors likely to have influenced acritical failure in incident investigations


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Likelihood of

operator error

Degree of

control overcompetingdemands

Practicality Degree of user

involvementin design

Model of factors influencing operatorerror

Time

sharingbetweenmultiple tasks

Provision of

Job aids

Communications

Time

pressureDistractionsCompetenceRoles &

ResponsibilitiesProcedures

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APPLICATIONS OF MITRE

Proactive applications Supports assessment of safety critical tasks to identify and

remedy any factors that may lead to an unacceptable errorprobability

Provides a benchmarking method for comparing different tasksin terms of their error potential

As part of the Predictive Human Error Analysis, allowsprediction of the likelihood of the identified errors based on anassessment of the Performance Influencing Factors

Incident investigation applications Specifies the factors that need to be assessed during the

investigation of actual incidents and near misses Prioritises which improvements will have the greatest effect on

preventing a recurrence of the incident

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USING THE HUMAN FACTORS TOOLS INCOMBINATION: ACCIDENT INVESTIGATION

Use Hierarchical Task Analysis to evaluate how thetask that failed is performed in practice (not as writtenin the procedures!)

Perform a Predictive Human Error Analysis (PHEA)on the task analysis to identify potential human errors

Analyse the accident sequence using STEP

Identify if any of the errors predicted by PHEAactually occurred in the accident sequence ( toevaluate the effectiveness of PHEA)

Evaluate the factors which influenced the occurrenceof these errors using MITRE Develop errorprevention strategies based on these analyses

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CONCLUSIONS

The Human Factors Workbench software provides

all the tools necessary to support human erroranalyses in safety and risk analyses

It has been used extensively in the UK to supporthuman reliability analyses required by the UK Health

& Safety Executive for safety cases

Users report that the HFW software is robust andeasy to use

Because all the tools are part of the same softwarepackage: It is easy to apply several tools in combination

Data can be shared between different analyses

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OBTAINING THE SOFTWARE

Demonstration versions of the software andmanuals are available from the followingwebsite:

www.humanreliability.com Further information is available from:

[email protected]
http://www.humanreliability.com/http://www.humanreliability.com/

Rio Pipeline Conference Presentation v5 (2)

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