Human Factor_Error Reduction Strategies

8/10/2019 Human Factor_Error Reduction Strategies

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Presentation Title (acronym) Data Collection for Safety performanceDivision Name/OPU/HCU/BU (acronym) - Chem Eng Dept. UTPName of Presenter Azizul b Buang

I m a g e f r o m :

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Error Reduction Strategies

CCB4613 Human Factors forProcess Safety


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Focus for Human Error Prevention Typical concern and generic strategy to

overcome the concernPrinciples of Error Countermeasures

Remedial Measure - Some ExampleDesigning To Avoid Human Error

Contents


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Introduction

Great deal of effort may be expended onhuman error detection, identification,delineation, and refinement,Butno real correction of the error problem canbe attained without some specificcountermeasure to control, contain, reduce,or eliminate the risks.


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Focus for Human Error Prevention Concern: Hazards

Response: Implement techniques by which to

recognize hazards. Eliminate hazards. Create barriers to prevent errors that

activate hazards, detect activated hazards,and mitigate the effects of hazards.

Implement techniques by which to makebarriers effective.


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Concern: Error-inducing conditions anderror-likely situations

Response:

Recognize error-inducing conditions anderror-likely situations. Eliminate these conditions and situations. Practice behaviors by which to counteract

error- inducing conditions and error-likelysituations.

Focus for Human Error Prevention


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Concern: Inappropriate risk-taking

Response: Recognize the behaviors that lead to non-

conservative decision-making. Practice behaviors that lead to

conservative decision making



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Concern: Recurrence of past errors

Response: Implement a field observation and

coaching system. Implement a problem reporting, root cause

analysis, and preventive corrective actionsystem.

Establish appropriate measures ofperformance.


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Principles of Error CountermeasuresThe following principles of error countermeasures serve to illustrate the intent,function, and general level of effectiveness of various remedies:

1. Eliminate source of human error (remove hazard) make error impossible bydesign

2. Control opportunity for error by physical means (engineering controls toprevent error e.g. guards or barriers to prevent access to a source oferror/hazard)

3. Mitigate consequences of an error (risk severity reduction)

4. Ensure detectability of errors before damage occurs (foster immediate errorcorrection)

5. Institute procedural pathways for guidance and to channel behavior (erroravoidance by restrictions and narrowing of conduct)

6. Maintain supervisory control and monitoring for errors (error observation, oraldirections, and manual shutdown) useful for new tasks, new employees, new

jobs, and new equipment


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The following principles of error countermeasures serve to illustrate the intent,

function, and general level of effectiveness of various remedies:7. Provided instructions that are written, brief, specific, and immediately available

8. Utilize training to provide general background information, job context,knowledge about company culture, and safety rules.

9. Have technical manuals available for reference when questions arise or for

general self-learning useful to help avoid troubleshooting errors10. Warnings provide an informed opportunity to avoid harm used for residual

risks after the use of other remedies

11. Specify that personal protective equipment or other safety equipment beavailable when and where needed for harm or injury reduction

12. Assume intentional risk acceptance by no error prevention action and atoleration of the results.

Principles of Error Countermeasures


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Specific Countermeasures

Single-error tolerance Important principle: a single human error should not result

in appreciable harm to persons or property Product, machine, or equipment should tolerate a simple

mistake or an honest error without giving rise to a

dangerous condition Human fault tolerance means a system will continue to

operate despite human error, loss or failure: built-in erroroverride, self-correction, and retained control are importantfor safety critical functions


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The rule of two Known that injuries could result from human error

or design error and the task of design engineers isto prevent adverse results due to such errors

Through two error design rule a danger will onlyensue when at least two independent human errorsor one error and one independent equipmentmalfunction occurred.

If the results could be catastrophic, increase therule to three error rule or more independentlyoccurring errors



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Interposition For a recalcitrant human error interpose

a barrier, shield, shroud or to otherwisedeny access to hazard or potential source

of harm e.g. point-of-operation guard Interposition separates error from the

source of harm.



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Remedial Measures - Example

Unfamiliarity

Time Shortage

Train operators tobe aware ofinfrequently-occurring conditions

Simulate each

situations Teach understanding

of consequencesConstant rehearsaland training toappreciate cost offailure


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Model mismatch

Spatial andFunctionalIncompatibility

Designers of systemfind out/consultusers expectationsand designcharacteristics into

systemProvision ofknowledge abouthuman engineeringfor populationstereotypes


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Poor Feedback

Delayed/IncompleteFeedback

Comprehensive taskanalysis will showpoints at whichfeedback must beavailable to operators

System responsetimes design toresponse below fourseconds & providesufficient informationto enable operators tostep confidently on tonext part of task



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ImpoverishedInformation Procedures should behuman-engineeredand tested foroperabilityProcedures must not

rely on accurateverbal transmission ofinformation forsuccess (assumedwhen personnelcommunicate- veryconsiderableinformation loss willoccur)



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InadequateChecking Independent checkson accuracy of taskby people andsystems that do nothave any vested

interest in successand failure of anindividualJob aids andsupervision shouldbe available tounburden operators



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Designing To Avoid Human Error

Make go als and sys tem s ta te v is ib le

Interfaces should make accessible, information in aform so that system state can be easily related tosystem operational goals.

Provide a goo d con ceptual m od el

It is important that operators be able to develop a goodconceptual model of the plant systems from training,from the design of the interface between the operatorand the plant, and from observations of system

operation. The information from these three sourcesshould be consistent and complementary to reduce thepossibility of operating errors.


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Make the acc eptable region s of op erat ion v is ible

Direct ly ind icat ing th e acc eptable, unacceptable, and desiredregions of system operation in process and state displays canact as a visual aid. This reduces dependence on user memoryrecall and the need for dynamic context dependentdeterminations. The adequacy of plant process state can thusbe judged more readily against performance targets.

Provid e appro priate feedb ack

Always p rov ide feedback for an operators actions. Feedbackcan take many forms. As a minimum, feedback should conveythe impact of the operators action on the overall state of thesystem.


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Ensure a c lose re lat ions hip b etween a co nt ro l and i t sfunc t ion

To reduce the demand on an operators memory, thereshould be a clear relationship between the location andmode of operation of a control and its function.

Bu ild-in const ra in ts

The users actions should be limited to acceptable ranges ofcontrol possibilities to guard against errors.


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Make in ter faces c on s is tentConsistency (and standardization) allows usersto apply existing knowledge to new tasks, Thisreduces the burden of interface characteristics

that must be learned and remembered.Minimizing the secondary tasks associated withtask performance can reduce the incidence ofoperating error.


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Addressing Human Error in the Design

First needs to characterize their potential foroccurrence and consequence for the operatingsituations encompassing system operation.


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Once the error environment is characterized,particular design solutions can be selected toachieve error reduction objectives.

By matching expected error causing situationswith appropriate design solutions, one canaddress potential human error occurrences orconsequences

A design solution strategy that preferentiallydeals with error occurrence first and errorconsequences second



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Eliminate Error Occurrence

This is the first preference, where design features known to be asource of human error are eliminated (e.g., lack of feedback, lack ofdifferentiation, inconsistent or unnatural mappings). Choices: Replacement of error inducing design features (e.g., physical

device separation, physical guards, application of validity andrange checking).

Restructuring of task so the error prevalent behaviour is no longerperformed (e.g., by information filtering, only the informationneeded for the task is provided).

Automate to change the role of human involvement in support oftask performance.



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Reduce Error Occurrence

Consider this approach if complete error elimination is notpossible or feasible through design choices. Design features: Identification (e.g., device labelling). Affordances (i.e., visually convey acceptable choices). Constraints (i.e., build in constraints to limit operation to

acceptable ranges). Coding (i.e., aid in choice differentiation and selection). Consistency. Feedback (i.e., convey device and system state directly in the

interface).



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Elim inate Error Consequence

The third approach is to eliminate error consequences. Interlocks Margins and Delays (i.e., these features can provide

more time to unacceptable consequence realizationthus increasing the chances of error detection andrecovery prior to consequence occurrence)

Fail Safe Features Alert of Unacceptable Device States (e.g.,

visual/auditory feedback of off-normal or unacceptabledevice states).



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Redu ce Error Con sequence

If errors and consequences can not be completelyeliminated, consider measures that enable consequencereduction.

This may be achieved through application of additionaldesign features that allow operators or automation torecognize the occurrence of an error consequence, andto take action to mitigate the consequences



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Margins (i.e., apply larger design margins to allow some

consequences to be accommodated by normal system functionand capacities).

Human Intervention / Response Teams (i.e., operations teamcan

readily adapt to both predefined and undefined operatingsituations, organizational structure is prepared and coordinatedto deal with the predefined consequences).

Consequence Prediction (e.g., aids can assist operations staffin predicting the extent of consequences of operating actionsand assist in selection and execution of mitigating actions).



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Thank you

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Human Factor_Error Reduction Strategies

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