8/10/2019 1200 - Brazier - Linking Task Analysis With Other Process Safety Activities

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Tel: (+44) 01492 879813 Mob: (+44) 07984 284642

andy@abrisk.co.ukwww.abrisk.co.uk

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Linking task analysis with other

process safety activities

Andy Brazier

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Working in silos

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QRA

HAZOP

Human factors

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Risk profile

Hazard detail

Engineered Human

Hierarchy Task or activity

1. Instrument

2. Alarm

3. Trip

4. MechanicalTaskanalysis

1. HMI

2. Deviation response

3. Emergency

4. Generic competence

5. One-off risk assessment

6. Automated

Prioritise according to risk of MAH

QRA, HAZID

Identify deviations leading to MAH

HAZOP, PHR

ALARP

HSE Roadmap

Barriers

Bowtie?

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HAZOP and human factors

Safeguards with human component

Monitoring and control

Alarm response

Training or procedure???

Safeguard maintenance

Tasks considered as potential causes of

deviationRecommendations.

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Issues with HAZOP and human factors

Not a systematic study of human factors

Human factors principles not always applied

(correctly)

HAZOP is already demanding without addinghuman factors

But creating good links between HAZOP and

human factors could be very beneficial.

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Use HAZOP to structure task analysis

HAZOP nodes

Focus on deviations that can result in Major

Accident hazards (MAH)

Use causes of deviations to identify tasks

Consistent reference to causes and

consequences.

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Identifying tasks

Planned deviations - pressure

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Pressure

Time

Start-up Normal Optimise Shutdown

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Unplanned deviations - pressure

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Pressure

Time

Start-upControlled

excursion

Failure

HazardUn-controlled

excursion

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Safety critical task analysis

What does safety critical mean?

What is a task?

What about non-tasks?

Prioritise to get the maximum benefit from the

effort put in

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Principles to apply

Area where MAH identified = safety critical

Safety Critical Task (SCT)

There is a clear start and finish

There are discrete steps

A change of status occurs

Safety Critical Activity (SCA) where the critical

aspects are:Timing (when to perform the task)

Tools and equipment to be used

Information presentation

Decision making 10

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Examples of SCT

Node start-up and shutdown

Starting main items of equipment

Stopping same equipment often simpler

Remove, calibrate and replace relief valve orbursting disk

Leak or pressure test.

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Examples of SCA & how to address

Control/optimise process

Human Machine Interfaces (EEMUA 191/201)

Emergency response

Emergency planning/staffing assessment

Routine maintenance/inspection

Planning and scheduling

Competence of personnel, permit to workOne-off tasks (e.g. temporary repair)

Risk assessment and management of change.

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SCT or SCA depends on circumstance

Changing operating mode

Manual stop or trip

Check/calibrate transmitter

Function test trip

Maintain process equipment

Contractor management

Prepare plant for maintenanceNormal shutdown?

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Conclusions

Linking human factors with other process safety

activities has great benefits

Linking all process safety activities should be the aim

Differentiating SCT and SCA helps clarify theway forward

Needs to be continuous and iterative

Changing the approach to human factors is not the

only requirement

Process safety studies need to be modified to provide

better date for human factors studies.

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