04365803 Hazard and Risc Evaluation

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HAZARD/RISK EVALUATION WHAT IS IT?

Copyright Material IEEEPaper No. PCIC-2007-41

Danny Liggett

Senior Member, IEEEDuPont Engineering

C/O CDI Engineering

9800 Centre Parkway

Suite 300

Houston, TX 77036

USA

[email protected]

Abstract - The term Hazard/Risk Evaluation is misunderstood.Some believe the procedures they have in place make up ahazard/risk evaluation. A Hazard/Risk Evaluation is a thought

process. Many have struggled with how to address therequirement for an evaluation contained in NFPA 70E [1].Many believe that Risk Management meets this requirement.This paper will provide one definition for what a Hazard/RiskEvaluation is and one method for performing a Hazard/RiskEvaluation. This paper will discuss risk assessment and how itfits in an overall risk management process. This paper willdiscuss the relationship between Risk Assessment andHazard/Risk Evaluation. The flowchart currently in NFPA 70Edoes not start with the right question and needs modifying. Thispaper will explore a new starting place for the thought processand suggest that the flow-chart in NFPA 70E needsmodification.

Index Terms Risk Management, Risk Analysis, Hazard

Risk Evaluation, Hazard, Risk

I. INTRODUCTION

Contained in the 2004 edition of NFPA 70E Section110.7(F), is a requirement for a Hazard/Risk EvaluationProcedure to be used. Annex F of NFPA 70E shows oneexample of how to accomplish this requirement. The problemis many people do not understand how to execute the processor even see the need for the process. They believe that theirprocedures, such as Working On or Near Energized ElectricalEquipment, satisfy the requirement. Most electrical safetyprocedures outline the Personal Protective Equipment to beused when performing tasks On or Near energized electricalequipment. What these procedures do not cover is how to

determine when an electrical hazard exposure is present. Thesame can be said of Risk Assessment programs. The primarypurpose of a Hazard/Risk Evaluation is to identify the electricalhazard exposure that may be encountered during the executionof a task or job. The Evaluation must identify both shock andarc flash hazard exposures. The evaluation is more of athought process than it is a procedure. It is a manner ofthinking about the task in a way that identifies the electricalhazards the person performing the task might be exposed to.

The thought process needs to be done in a specific sequencein order for it to be effective.

II. WHY DO A HAZARD/RISK EVALUATION?

Several years ago Ray Jones developed a model, shown inFig. 1, showing the relationship between regulations, standardsand procedures.

Fig 1 Control Measure Relationships

At the top of the triangle is government regulation. As youcan see the level of the detail is narrow. It is intended to be

more general in nature and written in performance-basedlanguage. Its purpose is not to tell you how to do something butrather what the end result must be. As we move down thetriangle the more detailed the information becomes. This is asit should be. The closer you get to the worker the informationand guidance needs to be more detailed and specific. Thebottom box of the triangle is the area within which the workerwill work. Jen Rasmussen concluded that Workers will makedecisions within boundaries established by administrative,functional and safety constraints [2]. Freedom left open by

GovernmentRegulations

National ConsensusStandards

CorporatePolicies

Site Requirements

Personal Beliefs


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lack of guidance sets the stage for human error. The pointis simple. The larger the box at the bottom the more decisionsthe worker has to make. The worker will make these decisionsbased upon that workers knowledge, experience and the toolsavailable to the worker at the time the task is being performed.The bottom box can only get deeper or shallower but it will notbe narrower. Many people think in terms of what do I need to

do and how do I do it. As part of this evaluation process weneed to help assure that they will also consider the safetyimplications.

Many incidents, injuries and fatalities have shown us that asingle action can start the chain of events that lead to theseincidents occurring. Completely controlling behaviors throughrigid and voluminous procedures cannot be done because ofthe complex nature and design of the electrical equipment andthe complexity of our facilities. These complexities provide somany possible situations a worker may face that procedurescannot address all of them. Because of this, there is a need tohelp assure that personnel use the right thought processes toplan any task they are given in a way that allows them tocomplete the task safely.

Having useful, practical procedures that set highly visible

boundaries within which the workers can work is a moreeffective way. Practical procedures allows for those cases thatwerent thought of during the development of the procedures.Even the most thorough procedures still leave room for workersto make some decisions. If we are to allow the kind of decisionmaking freedom required by the complexities, we must helpassure that the workers are given the tools to help guide theirdecisions.

Having a well-understood Hazard/Risk Evaluation processallows workers to work within the rules based upon theconditions of the area and equipment, and the objectives of thetask or job. The evaluation process provides the necessaryguidance for the worker to identify the hazards associated withthe job or task. The procedures established through riskmanagement at the site provide the necessary control

measures and personal protective equipment requirements toeliminate the hazards, reduce the hazards or address theremaining hazards.

III. RISK MANAGEMENT VERSUS HAZARD/RISKEVALUATION

Risk management is a method of identifying the potentialhazards of a process and provide the measures to addressthose hazards. Risk management is not task specific but ismore generic. Bill Anderson stated that concepts of safety aremore effective when they are applied early and throughout thedevelopment process [3]. Bill was referring to MachineDevelopment but it applies to electrical safety as well. RiskManagement is a tool that can be used to determine the risksassociated with the hazards in any work process, machine, orchemical process.

When electricity is present there is a shock hazard and anarc flash hazard. Part of risk management is defining theseverity of the hazard. Performing an arc flash analysis is partof electrical safety risk management. An arc flash studyidentifies the potential arc flash hazard for a piece ofequipment. Knowing the potential hazard, ways can be foundto mitigate the hazard or provide Personal ProtectiveEquipment (PPE) for use when there is a hazard exposure.

The arc flash analysis is not task specific. What the arc flashstudy does not do is identify when there is an exposure to anelectrical hazard while performing a specific job or task. Taskspecific hazard identification is the main difference between riskmanagement and hazard/risk evaluation.

Risk management assessments are usually performed well inadvance of jobs or tasks being performed. Basically it assists in

establishing control measures, in the form of safetyprocedures, and Personal Protective Equipment requirementsto be utilized when specific hazards are present. Thisassessment should be completed long before personnel facethe hazards.

The hazard/risk evaluation is performed during the planningstage of a job or task. Risk management, such as the arc flashstudy, is an important part of an overall safety program. Itidentifies the hazards and allows for the site to put theappropriate procedures in place so that when there is apotential exposure to a hazard the right work guidance andPPE is already available. Hazard/Risk Evaluation identifies ifthere is an electrical hazard exposure associated with anindividual job or task.

IV. RISK ASSESSMENT

Risk assessment is a part of risk management. Once thehazards are identified the risk assessment can be performed.

Risk assessments can be performed either quantitatively orqualitatively. Both systems look at the severity of the hazard,The frequency of the exposure and the probability of the hazardcausing an injury. Typically the formula is Severity x Exposurex Probability equals the risk value.

When a true quantitative analysis is performed all of thevariables are determined by using hard numbers. Severitycould be determined from using the amount of exposure to say,a chemical. If the person is exposed X amount of the chemicalthe person would suffer a recoverable injury. If the person is

exposed to Y amount then the person would sustain a disablinginjury. If the person is exposed to Z amount the exposurewould cause death. Each of these levels would be given avalue. Frequency of exposure to the specific hazard isdetermined by known experience similar to the way injuryfrequency rate is determined. Probability would again be basedupon actual experience. From the formula given above a risknumber is generated. As part of the quantitative analysis avalue or level is determined for what is considered anacceptable risk. Any value derived from the analysis above thisidentified level would require some action or actions to be takento lower the risk value.

A qualitative analysis is much more subjective and allows formore flexibility than having a number. A chart is developedusing the same three elements. The severity of the possibleinjury is broken into three levels, Lost Workday Case/Fatality,Medical Treatment Case/Restricted Workday Case, and First

Aid Case. Exposure consists of two levels, High and Low.Probability of injury is expressed as; Expected, Possible,Unusual, Borderline, Improbable, and Practically Impossible.

As you can see these breakdowns are not based uponnumbers. Each person will select the level of severity,exposure and probability element based on their individualexperiences. As with the quantitative method a level ofacceptable risk is established. Attachment A shows one


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example of this method and what is considered to be anacceptable risk.

One method that is becoming popular is a semi-quantitativeapproach [4]. It is a combination of the two methods discussedabove. The semi-quantitative approach still has the sameelements, severity, exposure and probability as the others but itis a combination of the two concepts. Attachment B provides

an example of one method of performing a semi-quantitativeanalysis. Each of the elements is broken down into 5 or 6levels and each level is given a numeric value. This allows theanalysis process to generate a numeric risk value. As with thequantitative method a level is established to define what is anacceptable risk.

All three of the concepts have some issues. All depend onelectrical injuries following the same spread as the injuries inthe other safety competencies. But experience by one largescience company indicates that the relationship betweenincidents, injuries and fatalities in electrical work do not followthe same relationship as they do in other safety competencies.The usual relationship in other competencies may be in therange of 300 recordable injures to 1 fatality. In electrical itapproaches 10 recordable injuries to 1 fatality.

Exposures to most hazards have a predictable injury. It iseasy to assume the more severe the hazard the more severethe resulting injury will be. Electrical hazards are not aspredictable. This is especially true with electrical shock.

Although 120 volts is a lethal level of voltage, a 120-voltelectrical shock is not always deadly. The same can be said ofhigher voltages. Again it is assumed that a shock at 15,000volts will result in a fatality. We know this is not always thecase. There are too many variables in an electrical shock toassume one will provide a mild tingle while another will becertain death. All electrical shocks over 50 volts must beconsidered as potentially fatal. An arc flash event has multiplehazards and it not yet completely understood. The arc flashevent with incident energies above 40 cal/cm

2is not predictable

enough to state with any accuracy what the outcome will be

other than there is a significant burn hazard and possibly asignificant blast pressure hazard. At lower levels, less than 40cal/cm

2, we can state there will be burns to unexposed skin and

we can somewhat predict whether these will be medicaltreatment, restricted workday, or lost workday cases. We donot know at what level of incident energy where death will be astrong possibility or certainty.

All of the concepts depend on the hazards being identifiedbefore beginning the analysis process yet none of them provideany guidance as to how to do this.

V. HOW TO DO A HAZARD/RISK EVALUATION

The purpose of the hazard/risk evaluation is to determine ifany hazards will be present and the extent of the hazardsduring the performance of a job or task. The hazard/riskevaluation is a thought process centered on a series ofquestions that need to be asked in a specific order. Think of itthis way. You are about to enter an electrical control room(ECR). As you step into the ECR you need to ask Is any of theequipment energized? then, Am I within the arc flashboundary of a piece of equipment? As you get closer you wantto ask Are there any openings in the equipment that exposeuninsulated energized components? As you continue to getcloser the questions change but the concept is to ask the

questions in the order in which you may be exposed to potentialhazards.

These questions should be asked to determine the hazardsassociated with the job or task. Jobs that contain multiple tasksshould be broken down into smaller tasks and each taskevaluated.

With electrical equipment both the arc flash hazard and the

shock hazard needs to be identified. The severity of the hazardneeds to be identified also. Each hazard needs to be dealt withseparately. Using a flow chart like the one in NFPA 70Eprovides us with the right questions to ask and the order theyneed to be asked.

The first question in the flow chart in Annex F of NFPA 70Easks if there is exposure to an energized electrical component.There is a perception that NFPA 70E only applies when thereis an exposure to uninsulated energized components.

The author suggests that the first question should bewhether there is any component in the equipment that isenergized. If there is to be any interaction with energizedelectrical equipment then this is an important question. Byknowing this we are driven to identify what component isenergized and its relationship to the interaction with the

equipment.Even if there is no exposure to energized electrical

equipment arc flash PPE may be required if the interaction iswithin the arc flash boundary of the equipment. Most electricalequipment in service today may not contain an arcing fault.Interaction with this electrical equipment may present an arcflash hazard. It needs to be determined if the interaction or taskwill be inside the arc flash boundary even with the door closedor if the equipment can contain an arcing fault. Knowing theworker will be inside the arc flash boundary is just one part ofthe arc flash hazard. We still need to know what the incidentenergy is so that the worker will have arc flash PPE appropriatefor the hazard exposure.

Understanding what is energized is just as important asunderstanding what is in an electrically safe work condition.

There are always hazards associated with working on or nearelectrical equipment that is or can be energized. Identifyingwhat is energized and where the energized components are isimportant for task planning. Too many incidents occur wherepeople get outside the electrically safe work condition andcontact energized components without realizing there were anyenergized components in the equipment.

Once it is established that some part of the equipment isenergized, the next question is to ask if there will be exposureto uninsulated energized components.

If there is exposure then the level of voltage needs to bedetermined. Knowing the voltage level will direct the person tothe shock protection rated for that voltage.

For the sake of discussion we will assume:

Some part of the equipment is energized

The task is inside the arc flash boundary

The incident energy is 5 cal/cm2

There is exposure to uninsulated energized conductors

The voltage is 480 voltsThe next step is to determine if there will be contact, by tools

or body parts, with uninsulated energized conductors. This isnecessary to differentiate between testing for the absence ofvoltage, measuring voltage, and performing work on energizedcomponents. If the task is to test for the absence of voltage therequirements may be different than measuring voltage. The


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site or company may choose to require the use of singlefunction testers for testing for the absence of voltage. Onethought is that we should not overly restrict the electrician fromtesting for the absence of voltage. Measuring voltage ordiagnostic tasks may require a different tester or meter.Performing work on energized components has a completelydifferent set of requirements. Lets assume there will not be

contact with energized components.We have established the following

Some part of the equipment is energized

The task is inside the arc flash boundary



The voltage is 480 volts No contact with uninsulated energized conductorsIf there will not be contact with uninsulated energized

conductors then how close will the person be to the uninsulatedenergized conductors? We know the voltage so we can usethe approach distance chart in NFPA 70E as a guide. If thework is inside the Limited Approach Boundary, in this case 42,but outside the Restricted Approach Boundary (12) therequirements for working in the Limited Approach space apply.

If the work is inside the Restricted Approach Boundary butoutside the Prohibited Approach Boundary (1) then therequirements of the Restricted Approach space apply. If thework is inside the Prohibited Approach Boundary then this isthe same as if you were in contact with the uninsulatedenergized conductors. Understanding the distance from theuninsulated energized components helps assure that the rightwork practices and PPE will be used. For discussion we willassume the task is in the Limited Approach space.

In some tasks long objects that could penetrate the otherApproach boundaries may be handled and this needs to beconsidered while performing the hazard/risk evaluation. We willassume no long objects will be handled.

Lets review what we know

Some part of the equipment is energized The task is inside the arc flash boundary



The voltage is 480 volts

No contact with uninsulated energized conductors

The work will be in the Limited Approach space.As you can see we have gathered several pieces of informationthat are critical to the safety of the worker. Now that we knowthis information what do we do with it?

By knowing that some part of the equipment is energized weknow there is an electrical hazard. Energized compartments,sections or parts can be identified. It can never be assumedthat people will know what is and what is not energized.Knowing the task will be performed inside the arc flash

boundary and knowing the level of the incident energy, we canprovide the appropriate arc flash PPE. Knowing there areexposed energized parts operating at 480 volts alerts us wemay need shock PPE. By understanding the distance from theenergized parts allows us to choose the appropriate workpractices and PPE for that task.

Having all of this information also provides us with fact-basedinformation by which we can determine whether we will performthe task with the equipment energized. When we arerequesting a shutdown of equipment we are usually dealing

with non-electrical personnel. Having the information on thehazards, the hazard levels and the required PPE will help non-electrical personnel make better decisions. It helps us makebetter decisions.

VI. TRAINING

This thought process is not intuitive. It requires training andexplaining. Today many, but not all people, understand there isa shock hazard and an arc flash hazard associated withelectricity. It is easy to assume that people will always thinkabout the right things and will always ask the right questions.

After all they are electricians. In the past it has been welldocumented by several companies that many electricians donot understand all of the hazards of electricity and cannot askthe right questions. Not only is it important to know whichquestions to ask but also why that question needs to be asked.The importance of each question must be conveyed in a waythat achieves understanding. Handing out a flow chart and

saying use this does not convey that understanding. Atraining session needs to be put in place to review thehazard/risk evaluation process that is to be used. Assumptionis proving to be a major contributor to electrical incidents.

VII. CONCLUSIONS

Risk Management consists of identifying the hazards andunderstanding the risks associated with them. Knowing thegeneral hazards associated with electrical work allows us tofeed that information into the Risk Assessment Analysis. Risk

Assessment allows us to establish a level of acceptable risk.The level of acceptable risk drives us to mitigate the hazards orto provide control measures and PPE when the hazards maystill be present. These are tools for management.

Hazard/Risk Evaluation is a tool for the worker to identifyhazards for jobs and tasks. Performing a Hazard/RiskEvaluation prior to starting any task is essential to the safeexecution of the task. Identifying the hazards associated withthe task is the only way to put the appropriate barriers betweenthe worker and the hazards. As you saw in Section V weidentified seven different pieces of information related toelectrical hazards. When we do a task do we think in a mannerthat would identify all seven of these items?

Not only is the evaluation needed for planning but also aschanges occur during the execution of the task or job.Changes occur on frequent basis therefore re-planning is justas important. This process needs to be stepped through forevery task.

A hazard/risk evaluation process is not one that comesnaturally. People are interested in the getting the job done andwill spend most of their time thinking in terms of what to doand how to do it. Too many people still believe being exposedto the hazards associated with electrical work is just part of the

job.If we provide procedures that dictate every action then we

are essentially saying to our workers check your brain at thegate. That is not what we need. We need people who canthink and make good decisions.


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If we depend solely on the worker to make the right choiceswithout some guidance then we are setting the stage forincidents, injuries and fatalities. No one gets up in the morningand says I think Ill go get hurt today. People show up at workevery day to do a good job. It is our responsibility to providethem with the tools to help them do that job in a way that it canbe completed safety. These tools include not only the drill

motors, hand tools, PPE and other physical equipment but alsothe mental tools that are needed to think about how to do thetask or job safely. One of those mental tools is a Hazard/RiskEvaluation Process.

A hazard/risk evaluation is the not the silver bullet or theanswer to all of our problems. With this evaluation we still haveto have in place the procedures that provide information suchas, what are the requirements for working in the Limited

Approach space and what arc flash PPE is required for 5cal/cm

2. The hazard/risk evaluation is one part of a holistic

approach to electrical safety. Employees need to understandthe basics of electrical safety such as the hazards of electricity.This comes from training. They need to know how to recognizewhen the electrical hazards are present. The hazard/riskevaluation helps them do this. They need to know how to

protect themselves from these hazards. Thats where theprocedures come in.

VIII. ACKNOWLEDGEMENTS

There are a lot of people who have influenced my thinkingconcerning electrical safety training. Every conversation I haveon electrical safety improves my understanding and thinking.Thanks to all. I would like specifically to thank Ray Jones whohas influenced my thinking and encouraged me to learn. Hecontinues to challenge and stretch my thinking.

Catherine Irwin and Aubrey Heflin provided insight into theuse of the Risk Assessment methods discussed in this paper,my thanks to them.

IX. REFERENCES

[1] NFPA 70E, 2004 Standard for Electrical Safety in theWorkplace, Quincy, MA: NFPA.

[2] Jens Rasmussen, Risk Management in a DynamicSociety: A Modeling Problem, Safety Science Vol. 27,No. 2/3, pp 183-213

[3] William E. Anderson, Risk Analysis Methodology Appliedto Industrial Machine Development, IEEE Transactionson Industry Applications, Vol. 41, No. 1, January/February2005

[4] A. M. Donoghue, The Design Of Hazard RiskAssessment Matrices For Ranking Occupational HealthRisks And Their Application In Mining And MineralsProcessing, Occup. Med. Vol. 5 No. 2, pp. 118-123, 2001

X. VITA

Danny Liggett has been employed by DuPont since 1989. Hewas employed by an Engineering /Construction firm from 1968until his employment by DuPont. During his employment withthe Engineering /Construction firm he worked as an ElectricalSuperintendent for over 15 years. During his employment withDuPont he has worked as an Electrical Consultant with primaryfocus on construction activities and electrical safety. His work

also involves work with maintenance activities at the DuPontsites. He is a member of DuPont's Corporate Electrical SafetyTeam. He is a Senior Member of the IEEE, past Chair for theIEEE PCIC Safety Subcommittee and past Chair for the IEEEPCIC Tutorial Subcommittee. He currently serves as the Chairfor the IEEE PCIC Electrical Safety Workshop Subcommittee.Danny has served as the chair for two of the IAS PCICElectrical Safety Workshops. He has served on NationalElectrical Code Panel 8 representing the Cable Tray Instituteand served as the Chair of the Technical Advisory Committeeto the Cable Tray Institute. He has served on the NationalElectrical Code Panel 6 representing the American ChemistryCouncil. He currently represents the American ChemicalCouncil as an alternate on the National Electrical CodeTechnical Correlating Committee and as an alternate on Panel

3.


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ATTACHMENT A

Quantitative Analysis Method

Severity Exposure

HighLWC/FatalityLowHighMTC/RWC

LowHighFAC

Low

Expected Possible Unusual Borderline Improbable PracticallyImpossible

Not Acceptable

Acceptable

Fig. 2 Quantitative Risk Evaluation Matrix


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ATTACHMENT B

Semi-Quantitative Method

Exposure

Very Rarely < 1 every year 0.5

Rarely Few times per year 1

Sometimes Once or twice a month 2Now & Then 1 every week 3

Frequently 1 every day 6

Continuous > 2 every day 10

SeverityMinor First aid case 1

Major Medical treatment or restricted workday case 4Serious Irreversible effect, handicap, Lost workday case 7

Critical One fatality, instantly or afterwards 15Disaster More than one fatality, instantly or afterwards 40

Probability

Virtually Impossible > 20 year, once in a life time, only theoretical case 0.2Conceivable Once in a career, 1 per 20 years 0.5

Improbable 1 per 10 years 1

Unusual 1 per 3 years 3Possibe 1 ever 6 months 6

Expected 1 every week 10

Exposure x Severity x Probability = Risk Score

Risk Score Interpretation200 Stop work until measures taken

Fig. 3 Semi-Quantitative Matrix

04365803 Hazard and Risc Evaluation

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