Safety Through DesignSafety Through Design

Bruce W. Main, PE CSPBruce W. Main, PE CSP

design safety engineering, inc.design safety engineering, inc.

Ann Arbor, MichiganAnn Arbor, Michigan10 Sept 200310 Sept 2003

Presentation OverviewPresentation Overview

• Safety through designSafety through design

• Why you should careWhy you should care

• Risk assessment basicsRisk assessment basics

• designsafedesignsafe demonstration and hints demonstration and hints

• ExamplesExamples

Safety Through Design... Safety Through Design...

• Design - optimizing against criteriaDesign - optimizing against criteria

• Late changes in criteria - safetyLate changes in criteria - safety

• Getting it right the first time Getting it right the first time

Familiar MethodsFamiliar Methods

• Government regulations (OSHA, FDA, etc.)Government regulations (OSHA, FDA, etc.)

• Industry standardsIndustry standards

• ChecklistsChecklists

• Safety factorsSafety factors

“Recent” Advances“Recent” Advances

• FMEA FMEA

• Failure Modes & Effects AnalysisFailure Modes & Effects Analysis

• Component failuresComponent failures

• Risk assessmentRisk assessment

• People failuresPeople failures

Safety Through Design…Safety Through Design…

• Getting it right the first time Getting it right the first time

• How?How?

• Risk assessmentRisk assessment

Why you should care…Why you should care…

• Your professors think it’s a good ideaYour professors think it’s a good idea

• Your grade depends on itYour grade depends on it

Other reasons to careOther reasons to care

• Industry standards are requiring risk assessmentIndustry standards are requiring risk assessment

• Europe - CE mark requires risk assessmentEurope - CE mark requires risk assessment

• Customers are beginning to require risk assessmentCustomers are beginning to require risk assessment

• Condition of saleCondition of sale

• Lots of momentum in industry in risk assessmentLots of momentum in industry in risk assessment

• Risk assessment worksRisk assessment works

• Better, cheaper, faster, more productiveBetter, cheaper, faster, more productive

The Basics...The Basics...

The Safety Hierarchy…

Forms the theoretical basis for design safetyForms the theoretical basis for design safety

The preferred approach to addressing hazards is:The preferred approach to addressing hazards is:

1. Eliminate the hazard by design1. Eliminate the hazard by design2. Substitute less hazardous work methods or materials2. Substitute less hazardous work methods or materials3. Incorporate safety devices (guarding systems)3. Incorporate safety devices (guarding systems)4. Provide warning systems4. Provide warning systems5. Apply administrative controls (work methods, training)5. Apply administrative controls (work methods, training)6. Provide personal protective equipment (PPE)6. Provide personal protective equipment (PPE)(Manuele: Innovations in Safety Management 2001(Manuele: Innovations in Safety Management 2001))

1. Determine the limits of the Machine

2. Hazard Identification

3. Risk Estimation

4. Risk Evaluation

5. Risk Reduction(Countermeasures)

6. Verify Implementation

7. Document Results ANSI B11 TR3ANSI B11 TR3

Hazard Analysis...Hazard Analysis...

• Identify hazardsIdentify hazards

• Task-based is a very useful approachTask-based is a very useful approach

• Focuses on what people doFocuses on what people do

• Users/tasks/hazardsUsers/tasks/hazards

• Brainstorming grounded in realityBrainstorming grounded in reality

Risk Assessment...Risk Assessment...

• Qualitative / semi-quantitative / quantitativeQualitative / semi-quantitative / quantitative

• Working to achieve acceptable riskWorking to achieve acceptable risk• risk which remains after protective measures risk which remains after protective measures

have been takenhave been taken

• risk which is accepted in a given contextrisk which is accepted in a given context

• Zero risk does not existZero risk does not exist

B11 TR3 MatrixB11 TR3 MatrixB11 TR3 MatrixB11 TR3 Matrix

NegligibleNegligibleNegligibleNegligibleLowLowLowLowRemoteRemote

NegligibleNegligibleLowLowMediumMediumMediumMediumUnlikelyUnlikely

LowLowMediumMediumHighHighHighHighLikelyLikely

MediumMediumHighHighHighHighHighHighVery LikelyVery Likely

MinorMinor

SeveritySeverity

ModerateModerate

Level ofLevel of

SeriousSeriousCatastrophicCatastrophic

Probability Probability of of

Occurrence Occurrence of Harmof Harm

MIL-STD-882D MatrixMIL-STD-882D MatrixMIL-STD-882D MatrixMIL-STD-882D Matrix

(E) IMPROBABLE(E) IMPROBABLE

( 10( 10-6 -6 > X ) > X )

(D) REMOTE(D) REMOTE

( 10( 10-3 -3 > X > 10> X > 10-6 -6 ))

(C) OCCASIONAL(C) OCCASIONAL

( 10( 10-2 -2 > X 10> X 10-3 -3 ))

(B) PROBABLE(B) PROBABLE

( 10( 10-1 -1 > X > 10 > X > 10-3 -3 ))

(A) FREQUENT(A) FREQUENT

( X > 10( X > 10-1 -1 ))

(4)(4)

NEGLIGIBLENEGLIGIBLE

(3)(3)

MARGINALMARGINAL

(2)(2)

CRITICALCRITICAL

(1)(1)

CATASTROPHICCATASTROPHIC

CATEGORY

FREQUENCY

UNACCEPTABLEUNACCEPTABLE

UNDESIRABLEUNDESIRABLE

ACCEPTABLE WITH REVIEWACCEPTABLE WITH REVIEW

ACCEPTABLE WITHOUT REVIEWACCEPTABLE WITHOUT REVIEW

R15.06 MatrixR15.06 MatrixR15.06 MatrixR15.06 Matrix

Table 2 – Risk reduction decision matrix prior to safeguard selection

R4R4A1A1 Likely Likely

R3BR3BA2 A2 Not LikelyNot LikelyE1E1 Infrequent Infrequent

exposureexposure

R3AR3AA1A1 Likely Likely

R2CR2CA2 A2 Not LikelyNot LikelyE2 E2 FrequentFrequent

exposureexposureS1S1 Slight Injury Slight Injury

First-aidFirst-aid

R2BR2BA1A1 Likely Likely

R2BR2BA2 A2 Not LikelyNot LikelyE1 E1 InfrequentInfrequent

exposureexposure

R2AR2AA1A1 Likely Likely

R1R1A2 A2 Not LikelyNot LikelyE2E2 Frequent Frequent

exposureexposureS2S2 Serious Injury Serious Injury

More thanMore than

First-aidFirst-aid

RISK REDUCTIONRISK REDUCTION

CATEGORYCATEGORYAVOIDANCEAVOIDANCEEXPOSUREEXPOSURESEVERITY OF INJURYSEVERITY OF INJURY

HFMEA Hazard Scoring MatrixHFMEA Hazard Scoring Matrix

Pro

bab

ilityP

rob

ability

Severity Severity CatastrophicCatastrophic MajorMajor ModerateModerate MinorMinor

FrequentFrequent 1616 1212 88 44

OccasionalOccasional 1212 99 66 33

UncommonUncommon 88 66 44 22

RemoteRemote 44 33 22 11

Risk Scoring SystemsRisk Scoring Systems

• Bringing structure to a subjective analysisBringing structure to a subjective analysis

• There is no one right approachThere is no one right approach

• This is subjectiveThis is subjective

• Become comfortable with subjectivityBecome comfortable with subjectivity

• The goal is acceptable riskThe goal is acceptable risk

Risk Assessment ResultsRisk Assessment Results

• New design requirements/criteria !!New design requirements/criteria !!• Assessment of risk: severity/probability ratingsAssessment of risk: severity/probability ratings• Road map for risk reduction activitiesRoad map for risk reduction activities• Framework for solutions (safety hierarchy)Framework for solutions (safety hierarchy)

• design changes, guarding systemsdesign changes, guarding systems• warnings, instructions, training, PPE requirementswarnings, instructions, training, PPE requirements

• Risk reduced to acceptable riskRisk reduced to acceptable risk

A DemonstrationA Demonstration

designsafe…designsafe…

Key Points about designsafeKey Points about designsafe

• Guides you through the risk assessment Guides you through the risk assessment processprocess

• Conforms to current standardsConforms to current standards• Helps you identify hazardsHelps you identify hazards• Prompts your risk reduction effortPrompts your risk reduction effort• Creates the documentationCreates the documentation• Free demo at Free demo at www.designsafe.comwww.designsafe.com

Too Much Residual Risk? What do you do?Too Much Residual Risk? What do you do?

Reduce Reduce

TransferTransfer

AvoidAvoid

AcceptAccept

When do we accept risk?When do we accept risk?

• When it’s insignificantly low.When it’s insignificantly low.

• When we are sure it is worth it.When we are sure it is worth it.

• When we do not know it is there.When we do not know it is there.

Tips on using designsafe…Tips on using designsafe…

• It is a guide. Use your head.It is a guide. Use your head.• Keep your eye on the goal Keep your eye on the goal

• Identify hazardsIdentify hazards• Reduce risks to an acceptable levelReduce risks to an acceptable level

• Risk scoring is not a scientific exercise.Risk scoring is not a scientific exercise.• Look for effective shortcutsLook for effective shortcuts

• All users, all tasksAll users, all tasks• Cut, copy, pasteCut, copy, paste

• Make it work for you.Make it work for you.

Example – Large Oven SystemExample – Large Oven System

• Oven system to bake finish on partsOven system to bake finish on parts

• Elevated, overhead locationElevated, overhead location

• Access required from time to timeAccess required from time to time

• Service conveyor, ovenService conveyor, oven

• Retrieve fallen partsRetrieve fallen parts

View Inside of OvenView Inside of Oven

Fallen Parts

Tripping Hazards

ProblemsProblems

• Lighting insufficientLighting insufficient

• Access difficultAccess difficult

• Introduced hazards to the workplaceIntroduced hazards to the workplace

• Task-based risk assessment finds theseTask-based risk assessment finds these

Perishable Goods ProcessingPerishable Goods Processing

• Packaging system to extend food shelf lifePackaging system to extend food shelf life

• Automated production system in operationAutomated production system in operation

• Sales wants small, manual system Sales wants small, manual system

• customers can “try before they buy”customers can “try before they buy”

• Prototype hand-held design in developmentPrototype hand-held design in development

• Risk assessment performedRisk assessment performed

New hazards identified New hazards identified

• Electrical equipment in wet environmentElectrical equipment in wet environment• - not hard wired- not hard wired

• Complex/confusing operation Complex/confusing operation • unmarked/confusing controls unmarked/confusing controls • high probability for operator errorhigh probability for operator error• equipment damage could occur if not equipment damage could occur if not

properly doneproperly done• Hand puncture – needle stickHand puncture – needle stick

Changes MadeChanges Made

• GFI addedGFI added• Design changes to greatly simplify Design changes to greatly simplify

proceduresprocedures• Entirely eliminated need for operator to Entirely eliminated need for operator to

adjust controlsadjust controls• Improved user information – manual, Improved user information – manual,

warnings, system ‘packagewarnings, system ‘package’’

• Puncture resistant gloves addedPuncture resistant gloves added

Common ThemesCommon Themes

• Must identify hazards earlyMust identify hazards early

• Early is better, faster, cheaper and more effectiveEarly is better, faster, cheaper and more effective

• Task based risk assessment helps identify more Task based risk assessment helps identify more

hazards hazards

• Allows engineers to reduce risksAllows engineers to reduce risks

• Risk assessment helps to determineRisk assessment helps to determine

• What, why, how and how muchWhat, why, how and how much

ReviewReview

• Safety through designSafety through design

• Why you should careWhy you should care

• Risk assessment basicsRisk assessment basics

• Demonstrated the process - Demonstrated the process - designsafedesignsafe

• Example risk assessment applicationsExample risk assessment applications