2012 young generation network - task analysis
TRANSCRIPT
Tel: (+44) 01492 879813 Mob: (+44) 07984 [email protected]
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Task AnalysisUsing the Flow Loop Simulator
Andy Brazier
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Overview
Develop a method for performing a defined task (1 hour)Consider the potential for human error (30 minutes)Determine how you will communicate your task method to operators and prepare (1 hour)Operators carry out task (1 hour).
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Hierarchical Task Analysis
A systematic way of describing task methodsEnsures the task is properly understoodOnly includes details that are necessaryCan be performed as a group exerciseAn excellent basis for:
Analysing human performance issuesWriting proceduresDeveloping training and competence programsDesign control rooms and interface
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Stages of the analysisDefine the task titleDefine the task’s starting point as a set of preconditionsIdentify the first level of sub-tasks
Should be less than 10Identify which sub-tasks need further analysis
Depends on criticality and/or complexityAgain, less than 10 task steps for each break-downContinue adding detail where required
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Connect tanker to delivery
point
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Transfer fuel from road-tanker to storage
Preconditions• Delivery from
approved supplier
• Tanker located in unloading bay
Transfer fuel using
tanker’s pump
Disconnect tanker from
delivery point
Confirm tanker is OK
to offload
Connect earth to tanker
Connect vapour
recovery hose
Connect delivery
hose between tanker & delivery
point
Open valves Check for leaks
Start tanker’s pump
Standby & monitor
throughout
When complete, stop pump and close
valves
Flow loop simulator
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Pump A
Pump B
Flow Control
Tank (1m3)
Reservoir Tank (1.5 m3)
PI
PI
TI
TT
FL1/DA/003
FL1/DA/008
FL1/DA/011
FL1/DA/016
FL1/DA/018
FL1/DA/001 FL1/DA/055A
FL1/DA/031A
FL1/DA/055B
FL1/DA/031B
FL1/DA/042
FL1/DA/013
NRV
FL1/DA/029A FL1/DA/026AFL1/DA/027A
NRV
FL1/DA/029B FL1/DA/026BFL1/DA/027B
PRV
FL1/DA/R038
PRV
FL1/DA/R039
FL1/DA/024
Return to reservoir tank
FL1/DA/TW01Liquid Supply
M
Manual valve
Motor operated valve
Non-return valve
Relief valve
PI Pressure indicator
PI
FL1/DA/054
Simplified flow
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Pump A
Pump B
Flow Control
Tank (1m3)
Reservoir Tank (1.5 m3)
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Group 1 – Start circulation
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Pump A
Reservoir Tank (1.5 m3)
Group 2 – Change circulation
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Pump B
Flow Control
Tank (1m3)
Reservoir Tank (1.5 m3)
Group 3 – Fill flow control tank to maximum level then shutdown
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Pump B
Flow Control
Tank (1m3)
Reservoir Tank (1.5 m3)
Controls and Instruments
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M
Manual valve
Motor operated valve
PI Pressure indicator
Non-return valve
Relief valve
You will need to use these to complete your task
No need to touch these
These may give some useful information in completing the task
Terminology
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Pump A
Inlet
Outlet
PI
Isolation valve
Key Requirements
Flow control tank must not go above its maximum level at any timeWhenever a pump is running
Reservoir Tank level between minimum and maximumPump inlet and outlet valves opensReservoir Tank outlet and loop valves openValve to either Reservoir or Flow tank open
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Your task analysis
Basic structureCheck it is OK to proceedSet up the loop as requiredConfirm everything is OK
Valve referencesDon’t just use Tag numbersRefer to valve list and include description and Tag number
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Human Error Analysis
A systematic way of identifying potential human errors
Making sure all credible errors are consideredRecording the possible consequencesEvaluating exiting risk control measures and opportunities for further reduction
Simple and effective method of tackling an issue that is often considered to be complex and problematic.
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First – Convert task analysis to tabular
1. Confirm tanker is OK to offload2. Connect tanker to delivery point
2.1 Connect earth to tanker2.2 Connect delivery hose between tanker & delivery point2.3 Connect vapour recovery hose
3. Transfer fuel using tanker’s pump3.1 Open valves3.2 Start tanker’s pump
Consider consequence for each step if
Omitted (not carried out)IncompletePerformed on the wrong objectMistimed (too early or late)Carried out at the wrong speed (too fast or slow)Carried out for the wrong duration (too long or too short)Performed in the wrong direction.
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20202020
Task Step Possible error Existing risk control measuresConsequence Additional
measures
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Connect earth to tanker
Action omitted -
Potential for static discharge to act as source of ignition
Failure to achieve an earth before starting transfer.
Standard practice for all tanker operations.
Consider installing interlocked earth connection.Earth
connection readily available.
212121212121
Task Step Possible error Existing risk control measuresConsequence Additional
measures
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Dis-connect tanker from delivery point
Action omitted or incomplete -
Damage to hoses, plant or tanker.
Not properly disconnected
Driver responsibilityError unlikely
None.
Action too early -Disconnect hose whilst transferring
Release of material being transferred.
Noise will alert operator to fact transfer is ongoing.
None.
How will you communicate your task?
ProcedureSimple and logicalPresented in an easy to follow formatEmphasise hazards and critical steps
Training Task objectivesHazardsCritical stepsDo they understand?
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Human performance and error avoidance tools
Recognise where errors can occur and adopt tools to minimise likelihood
Pre-job briefSTAR (Stop, Think, Act, Review)Self checkingPeer checkingProcedure use, adherence and place-keepingQuestioning attitudeClear communication.
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What you need to do now
Convert your task analysis to tabular formatComplete human error analysis for the most critical stepsDevelop a plan to communicate your task method to operators from another group.
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Practicalities
PPE
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Practicalities
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Valves
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Open Closed
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Open Closed
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