Risk AnalysisRisk Analysis

A methodology to evaluate the probability of an A methodology to evaluate the probability of an adverse effect of an agentadverse effect of an agentAdverse effect can be loss of limb, loss of life, Adverse effect can be loss of limb, loss of life, cancer, or damage due to a fire/explosioncancer, or damage due to a fire/explosionThe same event can cause various effects, some The same event can cause various effects, some worse than othersworse than others

Risk is the product of the magnitude of the Risk is the product of the magnitude of the effect and the probability of it occurringeffect and the probability of it occurring

Chopping VegetablesChopping Vegetables

Probability of getting a Probability of getting a cut is highcut is highConsequence is low Consequence is low –– a a nick rather than deathnick rather than deathThe risk is quite lowThe risk is quite low

Chemical AgentsChemical Agents

Hazard IdentificationHazard IdentificationDetermine the doseDetermine the dose--response relationshipresponse relationshipDetermine the exposure timeDetermine the exposure timeCharacterize the riskCharacterize the risk

HistoryHistory

VitruviousVitruvious (~100 BC) observed lead toxicity (~100 BC) observed lead toxicity (acidic wine and lead goblets!)(acidic wine and lead goblets!)John Evelyn linked scrotal cancer with chimney John Evelyn linked scrotal cancer with chimney sweeperssweepersJohn Snow linked a London cholera outbreak to John Snow linked a London cholera outbreak to a specific contaminated wella specific contaminated well

Two ApproachesTwo Approaches

DoseDose--Response CurvesResponse Curves

These are the primary tool for These are the primary tool for ModellingModelling Effects Effects for chemical exposure (people or animals)for chemical exposure (people or animals)No Observable Effect Level (NOEL) No Observable Effect Level (NOEL) ––threshold below which no effect is observedthreshold below which no effect is observedPeople are considered 10 times more susceptible People are considered 10 times more susceptible than animalsthan animals

∫=2

1

)()(t

tpot dttIRtCD ∫=2

1

)()(t

tpot dttIRtCD ∫=2

1

)()(t

tpot dttIRtCD

∫=2

1

)()(t

tpot dttIRtCD

DoseDose--Response CurvesResponse Curves

Dose Response Curves

0

10

20

30

40

50

60

70

80

90

100

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Dose (mg/kg)

% o

f Pop

ulat

ion

Irritation Systemic Effect Death

Toxic Chemicals RiskToxic Chemicals Risk

Average body parameters are usedAverage body parameters are used(70 kg mass, 2 L/day water and 20 m(70 kg mass, 2 L/day water and 20 m33/day air)/day air)

Acute ToxicityAcute ToxicityLDLD5050 (death within 24 hours)(death within 24 hours)LCLC5050 (death within 24 hours)(death within 24 hours)

Paracelsus (16Paracelsus (16thth century) century) The Dose makes the PoisonThe Dose makes the Poison

Toxicity Toxicity RankingRanking

Probable Probable Lethal Lethal DoseDose

UnitsUnits Chemical Chemical ExampleExample

LDLD

5050

(animals)(animals)

Practically Practically nonnon--toxictoxic

>15>15 g/kgg/kg

Slightly toxicSlightly toxic 5 5 --

1515 g/kgg/kg EthanolEthanol 10 g/kg10 g/kg

Moderately Moderately toxictoxic

0.50.5--55 g/kgg/kg Sodium Sodium chloridechloride

4 g/kg4 g/kg

Very ToxicVery Toxic 50 50 ––

500500 mg/kgmg/kg PhenobarbitalPhenobarbital 150mg/kg150mg/kg

Extremely Extremely toxictoxic

5 5 ––

5050 mg/kgmg/kg PicrotoxinPicrotoxin 5 mg/kg5 mg/kg

SupertoxicSupertoxic <5<5 mg/kgmg/kg DioxinDioxin 0.001 mg/kg0.001 mg/kg

Chemical ExposureChemical Exposure

Remember Remember –– some chemicals do not pose acute some chemicals do not pose acute chemical hazards but have other hazardschemical hazards but have other hazardsPolychlorinated biphenyls (PCBs)Polychlorinated biphenyls (PCBs)

LD50 (oral LD50 (oral –– rodents): 1 rodents): 1 –– 11 g/kg11 g/kgNOEL (oral NOEL (oral -- rodents): 12 rodents): 12 –– 50 mg/kg for 50 mg/kg for teratogenicteratogenic, carcinogenic and , carcinogenic and immunotoxicityimmunotoxicity

Some chemicals Some chemicals bioaccumulatebioaccumulate as wellas well

EpidemiologyEpidemiology

The study of factors that affect health and The study of factors that affect health and illnesses in populationsillnesses in populationsDisease rates are compared between Disease rates are compared between ““exposed exposed personspersons”” and and ““nonnon--exposed personsexposed persons””Retrospective in nature Retrospective in nature –– many diseases have a many diseases have a long latency periodlong latency periodSamples sizes need be largeSamples sizes need be largeWatch for confounding effects (Watch for confounding effects (egeg., smoking)., smoking)

Health EffectsHealth Effects

For chemical effects, we can model the effects For chemical effects, we can model the effects using animal studies or epidemiologyusing animal studies or epidemiologyOccupational Health and Safety addresses the Occupational Health and Safety addresses the workplace issues to keep exposures at acceptable workplace issues to keep exposures at acceptable levelslevelsHow to rank various chemicals and/or various How to rank various chemicals and/or various process devices for the relative risks?process devices for the relative risks?

DOW Chemical Exposure IndexDOW Chemical Exposure Index DOW Fire and Explosion IndexDOW Fire and Explosion Index

Methods for identifying and quantifying various Methods for identifying and quantifying various release scenariosrelease scenariosThey provide a dimensionless number that They provide a dimensionless number that allows for a relative ranking of the risk of the allows for a relative ranking of the risk of the scenario or devicescenario or device

DOW CEIDOW CEI

Used to rank the acute health potential for Used to rank the acute health potential for people in people in neighbouringneighbouring communities or plantscommunities or plantsSuitable for volatile chemicals onlySuitable for volatile chemicals onlyConsiders liquid or Considers liquid or vapourvapour releases from processreleases from process

Scenarios last for 5 minutesScenarios last for 5 minutes

Emergency and Risk Planning Emergency and Risk Planning GuidelinesGuidelines

ERPGERPG--1: maximum airborne concentration below 1: maximum airborne concentration below which all nearly individuals can be exposed for 1 hr which all nearly individuals can be exposed for 1 hr without effects (without effects (odourodour threshold or ERPGthreshold or ERPG--2/10)2/10)ERPGERPG--2: maximum airborne concentration that nearly 2: maximum airborne concentration that nearly all individuals can be exposed for 1 hr without serious all individuals can be exposed for 1 hr without serious health effects (ACGIH TLV)health effects (ACGIH TLV)ERPGERPG--3: maximum airborne concentration below 3: maximum airborne concentration below which nearly all individuals can work for 1 hr without which nearly all individuals can work for 1 hr without experiencing life threatening effects (LCexperiencing life threatening effects (LC5050/30 or 5* /30 or 5* ERPGERPG--2)2)

Identify Release ScenariosIdentify Release Scenarios

ScenariosScenarios

Vessel Vessel –– full release in 10 minutesfull release in 10 minutesPipe Pipe –– assume full rupture of 2assume full rupture of 2”” pipepipe

>4>4”” pipe assume loss through 20% of areapipe assume loss through 20% of area

PR devices PR devices –– determine total release ratedetermine total release rateTank overflows Tank overflows –– spill = maximum tank inputspill = maximum tank input

Airborne Quantity Airborne Quantity

Gas Release Gas Release –– sonic velocitysonic velocity

Pa Pa –– absolute pressure (absolute pressure (kPakPa); MW ); MW –– mol weight;mol weight;T T –– temperature (C); D diameter in mmtemperature (C); D diameter in mm

27310751.4 26

+= −

TMWPDxAQ a

Liquid ReleaseLiquid Release

Determine liquid release rate and flash fraction Determine liquid release rate and flash fraction

PPgg -- gauge pressure (gauge pressure (kPakPa); ); ρρll -- density (kg/mdensity (kg/m33))ΔΔhh –– liquid height above the release point [m]liquid height above the release point [m]

hP

DxLl

gl Δ+= − 8.9

10001044.9 27

ρρ

)(;5 bsv

pvvv TT

HC

FLFAQ −==

DOW CEI and Hazard DistanceDOW CEI and Hazard Distance

Hazard distance is the radius to that Hazard distance is the radius to that concentrationconcentration

21.655

−=

ERPGAQCEI

ERPGAQHD 6551=

Ammonia ExampleAmmonia Example

Ammonia is stored in a 12 ft diameter by 72 ft long horizontal Ammonia is stored in a 12 ft diameter by 72 ft long horizontal vessel under its own vapor pressure at ambient temperature vessel under its own vapor pressure at ambient temperature (30(30°°C or 86C or 86°°F). The largest liquid line out of the vessel is 2 inch F). The largest liquid line out of the vessel is 2 inch diameter (50.8 mm).diameter (50.8 mm).PPgg (pressure inside vessel) = 1064 (pressure inside vessel) = 1064 kPakPa gaugegaugeT (temperature inside vessel) = 30T (temperature inside vessel) = 30°°CCTTbb (normal boiling point) = (normal boiling point) = --33.433.4°°CCρρll (liquid density) = 594.5 kg/m3(liquid density) = 594.5 kg/m3CCpp//HHvv = 4.01*10= 4.01*10--33

ΔΔh (height of liquid in tank) = 3.66 mh (height of liquid in tank) = 3.66 mD (diameter of hole) = 50.8 mmD (diameter of hole) = 50.8 mmMW (molecular weight) = 17.03MW (molecular weight) = 17.03

CalculationsCalculations

AQ = 61.9 kg/sec; ERPGAQ = 61.9 kg/sec; ERPG--2 = 1392 = 139 mg/mmg/m33

kg/sec 61.9 )66.3(8.9)5.594(

)1064(1000)5.594()8.50(1044.9 27 =+= −xL

254.0)]30(30[*00401.0)( =−−=−= bsv

pv TT

HC

F

4372

1.655 =−

=ERPG

AQCEI

mERPG

AQHD 372,42

6551 =−

=

DOW FEIDOW FEI

Simple method for rating the realistic fire or Simple method for rating the realistic fire or explosion potential of storage or processing explosion potential of storage or processing equipmentequipmentMaterial FactorMaterial Factor

intrinsic rate of potential energy releaseintrinsic rate of potential energy release

General Process Hazard FactorGeneral Process Hazard FactorPrimary role in magnitude of the lossPrimary role in magnitude of the loss

Special Process HazardsSpecial Process Hazards

Material FactorMaterial Factor

NFPA DiamondNFPA DiamondHealth Health –– BlueBlueFire Fire –– RedRedReactivity Reactivity -- YellowYellow

Liquids or Gases Flammability

1 Nr = 0 Nr = 1 Nr = 2 Nr = 3 Nr = 4

Non-combustible 2 NF

= 0 1 14 24 29 40

F.P. > 200 F NF

= 1 4 14 24 29 40

F.P. > 100F & < 200 F NF

= 2 10 14 24 29 40

F.P. >73 F & < 100F, ORF.P. < 73 F & B.P. > 100F

NF

= 3 16 16 24 29 40

F.P. < 73 F & B.P. < 100 F NF

= 4 21 21 24 29 40

Combustible Dust / Mist3

St-1 (Kst

< 200 bar m/sec) 16 16 24 29 40

St-2 (Kst

200 -

300 bar m/sec) 21 21 24 29 40

St-3 (Kst

> 300 bar m/sec) 24 24 24 29 40

Combustible Solids

Dense > 40 mm thick 4 NF

= 1 4 14 24 29 40

Open < 40 mm thick 5 NF

= 2 10 14 24 29 40

Foam, fiber, powder, etc. 6 NF

= 3 16 16 24 29 40

General Process FactorGeneral Process Factor

A. Exothermic reactions such as alkylation, A. Exothermic reactions such as alkylation, halogenationhalogenation or nitration. or nitration. B. Endothermic reactions such as cracking or B. Endothermic reactions such as cracking or pyrolysispyrolysis..C. Loading or unloading flammables or LPGC. Loading or unloading flammables or LPG’’s or any s or any process such as centrifuging where introduction of air process such as centrifuging where introduction of air might occurmight occurD. For indoor or highly confined units.D. For indoor or highly confined units.E. Access from at least two different directions for fire E. Access from at least two different directions for fire fighting equipment is the aim.fighting equipment is the aim.F. Good drainage and spill control results in no penalty.F. Good drainage and spill control results in no penalty.

Special Process FactorSpecial Process Factor

ToxicityToxicitySubSub--Atmospheric PressureAtmospheric PressureOperation in or near the flammable range Operation in or near the flammable range Dust Explosion Dust Explosion Relief Pressure the pseudoRelief Pressure the pseudo--ratio of operating pressure to the ratio of operating pressure to the relief pressure. relief pressure. Low Temperature Operation Low Temperature Operation Quantity of Material Quantity of Material Corrosion/Erosion Leakage gaskets, seals and Corrosion/Erosion Leakage gaskets, seals and packingspackings (also (also glass devices and bellows) can be sources for leaks glass devices and bellows) can be sources for leaks Fired Equipment Fired Equipment Hot Oil System Hot Oil System Rotating EquipmentRotating Equipment

AREA / COUNTRY DIVISION LOCATION DATE

SITE MANUFACTURING UNIT PROCESS UNIT

PREPARED BY: APPROVED BY: (Superintendent) BUILDING

REVIEWED BY: (Management) REVIEWED BY: (Technology Center) REVIEWED BY: (Safety & Loss Prevention)

MATERIALS IN PROCESS UNIT

STATE OF OPERATION ___ DESIGN ___ START UP ___ NORMAL OPERATION ___ SHUTDOWN

BASIC MATERIAL(S) FOR MATERIAL FACTOR

MATERIAL FACTOR (See Table 1 or Appendices A or B) Note requirements when unit temperature over 140 oF (60 oC)

1. General Process Hazards

Penalty Fac-tor Range

Penalty Fac-tor Used(1)

Base Factor ................................................................................................................. 1.00 1.00 A. Exothermic Chemical Reactions 0.30 to 1.25 B. Endothermic Processes 0.20 to 0.40 C. Material Handling and Transfer 0.25 to 1.05 D. Enclosed or Indoor Process Units 0.25 to 0.90 E. Access 0.20 to 0.35 F. Drainage and Spill Control __________ gal or cu.m. 0.25 to 0.50

General Process Hazards Factor (F1) .................................................................................................

2. Special Process Hazards Base Factor ................................................................................................................. 1.00 1.00 A. Toxic Material(s) 0.20 to 0.80 B. Sub-Atmospheric Pressure (< 500 mm Hg) 0.50 C. Operation In or Near Flammable Range ___ Inerted ___ Not Inerted 1. Tank Farms Storage Flammable Liquids 0.50 2. Process Upset or Purge Failure 0.30 3. Always in Flammable Range 0.80 D. Dust Explosion (See Table 3) 0.25 to 2.00 E. Pressure (See Figure 2) Operating Pressure ________ psig or kPa gauge Relief Setting ________ psig or kPa gauge

F. Low Temperature 0.20 to 0.30 G. Quantity of Flammable/Unstable Material: Quantity _____ lb or kg HC = _____BTU/lb or kcal/kg

1. Liquids or Gases in Process (See Figure 3) 2. Liquids or Gases in Storage (See Figure 4) 3. Combustible Solids in Storage, Dust in Process (See Figure 5) H. Corrosion and Erosion 0.10 to 0.75 I. Leakage – Joints and Packing 0.10 to 1.50 J. Use of Fired Equipment (See Figure 6) K. Hot Oil Heat Exchange System (See Table 5) 0.15 to 1.15 L. Rotating Equipment 0.50

Special Process Hazards Factor (F2) .................................................................................................

Process Unit Hazards Factor (F1 x F2) = F3 ..................................................................................

Fire and Explosion Index (F3 x MF = F&EI) .................................................................................... (1) For no penalty use 0.00.

CEI FEI SummaryCEI FEI Summary

Easy to use toolsEasy to use toolsConsistent in approachConsistent in approach

Qualitative in approach Qualitative in approach –– they do not look at they do not look at specific causes and the risk associated with eachspecific causes and the risk associated with each

Two ApproachesTwo Approaches

Quantitative Risk AnalysisQuantitative Risk Analysis

Generate scenarios for hazardous eventsGenerate scenarios for hazardous eventsDetermine the magnitude of the hazard and the Determine the magnitude of the hazard and the probability of its occurringprobability of its occurringNext Next –– identify the mitigation strategy and costidentify the mitigation strategy and cost

Determine whether mitigation adds valueDetermine whether mitigation adds valueRemember that adding one safety device may well Remember that adding one safety device may well make another scenario less safe!make another scenario less safe!

Layers of ProtectionLayers of Protection

A process has its normal control systems A process has its normal control systems (operator and computer based)(operator and computer based)There are emergency safety systems (operator There are emergency safety systems (operator and computer based)and computer based)There are physical barriers around the plant There are physical barriers around the plant (curbs and (curbs and dykingdyking))The plant will have onThe plant will have on--site and offsite and off--site site emergency countermeasures (police, fire emergency countermeasures (police, fire department and ambulance).department and ambulance).

ScenariosScenarios

All scenarios start with an initiating event. All scenarios start with an initiating event. If the control system works, the event is dealt If the control system works, the event is dealt with. with. If the control system does not resolve the issue, If the control system does not resolve the issue, then the emergency safety system is activated. then the emergency safety system is activated. If the problem continues, then plant relies on If the problem continues, then plant relies on physical barriers. physical barriers. Ultimately, external resources are brought in to Ultimately, external resources are brought in to address the situation. address the situation.

ReleasesReleases

The typical hazard in the CPI is the release of The typical hazard in the CPI is the release of the chemicalsthe chemicalsA root cause could be the addition of an A root cause could be the addition of an impurity, when leads to corrosion, which causes impurity, when leads to corrosion, which causes a hole when there is a pressure surge. a hole when there is a pressure surge. The pressure surge is the initiating eventThe pressure surge is the initiating eventThe root cause is the impurityThe root cause is the impurity

Liquid Loss Though a Pipe HoleLiquid Loss Though a Pipe Hole

Co Co –– discharge coefficient discharge coefficient approaches 0.61 for sharp edges holesapproaches 0.61 for sharp edges holesapproaches 1 for round holes approaches 1 for round holes

gomg

o PACQandP

Cu ρρ

2;2

==

∑+=

fo

KC

11

Liquid Loss Though a Tank HoleLiquid Loss Though a Tank Hole

hhll is the liquid height above the hole is the liquid height above the hole

LgomLg

o ghPACQandghP

Cu 22;2

ρρρ

+=+=

⎥⎥⎦

⎤

⎢⎢⎣

⎡++=

ρρgo

Lg

oe

Pgh

gPAAt

gCt

2)(2)(1

VapourVapour

Losses through a HoleLosses through a Hole

Maximum is sonic velocityMaximum is sonic velocity

⎥⎦

⎤⎢⎣

⎡−

+= + )/1(/2 )()(

12 γγγ

γγ

ooooom P

PPP

RTMPACQ

)1/()1(, )

12( −+

+= γγ

γγ

ooochokedm RT

MPACQ

Other CasesOther Cases

Flashing liquidFlashing liquid

Liquid Pool evaporationLiquid Pool evaporation

NonNon--stagnant stagnant evaporationevaporation

Evaporation due to heat Evaporation due to heat from the groundfrom the ground

vap

bomv H

TTCpQM

Δ−

=)(

L

sat

m RTPAKMQ =

t

TTkq

HAq

Qs

gsg

vap

gm πα

)(;

−=

Δ=

Lsys

sat

m TRPPVMQ =

Dispersion ModelsDispersion Models

The scenario defines the maximum release rateThe scenario defines the maximum release rate

For For vapourvapour releases, the downwind releases, the downwind concentrations are determined using a concentrations are determined using a Dispersion ModelDispersion Model

PasquillPasquill--Gifford ApproachGifford Approach

K* is the eddy diffusivityK* is the eddy diffusivity

222*4),,(

zyxK

QzyxC m

++=

π

⎪⎭

⎪⎬⎫

⎪⎩

⎪⎨⎧

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛ +−+

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛ −−

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛−=

222

*5.0exp*5.0exp**5.0exp2

),,(z

r

z

r

yzy

m HzHzyu

QzyxC

σσσσσπ

Pasquill-Gifford Stability Class

σy

(m) σz

(m)

Rural –

A –

extremely unstable

0.22x * (1 + 0.0001x)-0.5 0.20x

Rural –

B –

moderately unstable

0.16x * (1 + 0.0001x))-0.5 0.12x

Rural –

C –

neutrally unstable

0.11x * (1 + 0.0001x)-0.5 0.08x * (1 + 0.0002x)-0.5

Rural –

D –

neutrally stable

0.08x * (1 + 0.0001x)-0.5 0.06x * (1 + 0.0015x)-0.5

Rural –

E –

slightly stable 0.06x * (1 + 0.0001x)-0.5 0.03x * (1 + 0.0003x)-0.5

Rural –

F –

moderately stable

0.04x * (1 + 0.0001x)-0.5 0.016x * (1 + 0.0003x)-0.5

Urban –

A/B –

moderately unstable

0.32x * (1 + 0.0004x)-0.5 0.24x * (1 + 0.0001x)-0.5

Urban –

C –

neutrally unstable

0.22x * (1 + 0.0004x)-0.5 0.20x

Urban –

D –

neutrally stable

0.16x * (1 + 0.0004x)-0.5 0.14x * (1 + 0.0003x)-0.5

Urban –

E/F –

moderately stable

0.11x * (1 + 0.0004x)-0.5 0.08x * (1 + 0.0015x)-0.5

ExplosionsExplosions

Damage due to explosions is caused by the Damage due to explosions is caused by the pressure wavepressure waveScaled distance z = r/(mScaled distance z = r/(mTNTTNT))1/31/3

TNT equivalency is the mass * heat of combustion, TNT equivalency is the mass * heat of combustion, divided by 1120 kcal/kg (TNT equivalent)divided by 1120 kcal/kg (TNT equivalent)Usually ~3% of energy converted to pressure waveUsually ~3% of energy converted to pressure wave

Effect of PressureEffect of Pressure

EffectEffect Overpressure Overpressure ((kPakPa))

Occasional breaking of large glass Occasional breaking of large glass 0.20.2

Limited minor structural damage Limited minor structural damage 2.82.8

Minor damage to house structures Minor damage to house structures 4.84.8

Partial demolition of houses, made uninhabitable Partial demolition of houses, made uninhabitable 6.96.9

Partial collapse of walls and roofs of houses Partial collapse of walls and roofs of houses 13.813.8

Probable total destruction of buildingsProbable total destruction of buildings 6969

Limit of crater lip Limit of crater lip 20002000

Scaled DistanceScaled Distance

Scaled Distance

0.01

0.1

1

10

100

0.1 1 10 100

ze (m/kg^1/3)

Pmax

(P/P

amb)

BLEVE/UVCEBLEVE/UVCE

Boiling Liquid Expanding Boiling Liquid Expanding VapourVapour ExplosionExplosionUnconfined Unconfined VapourVapour Cloud ExplosionCloud Explosion

Release for some time, with ignition found at Release for some time, with ignition found at some distance some distance –– significant mass of explosive significant mass of explosive material, and significant damagematerial, and significant damage

Probabilistic SideProbabilistic Side

Stochastic issues are random eventsStochastic issues are random eventsSystemic issues where the design impacts the Systemic issues where the design impacts the probabilityprobability

Automobile deathsAutomobile deathsCanada Canada -- 9 per 100,000 population9 per 100,000 populationWorld World –– 9 per billion km driven9 per billion km driven

Mostly stochastic, but seat belts have an effectMostly stochastic, but seat belts have an effect

StatisticsStatistics

Carcinogenic Risk = Carcinogenic Risk = ββ κκ DDProduct of carcinogenicity in animals, interspecies Product of carcinogenicity in animals, interspecies conversion and doseconversion and dose

UncertaintyUncertainty

2222DR σσσσ β ++= Κ

How Likely is it to go WrongHow Likely is it to go Wrong

Best approach is to use historical dataBest approach is to use historical dataHow frequently does a pump or valve fail?How frequently does a pump or valve fail?

For events that are follow an initiating eventFor events that are follow an initiating event

)...(*)(*)()( IEBfIEAfIES φφ =

Testing FrequencyTesting Frequency

The likelihood of failure on demand increases The likelihood of failure on demand increases with the time lag between testswith the time lag between testsSuppliers (or historical frequency) * ratio of Suppliers (or historical frequency) * ratio of testing frequency to manufacturers frequencytesting frequency to manufacturers frequency

)/T(T * P GFCFCF λ=

Risk ManagementRisk Management

Safety Risk Safety Risk –– these are usually low probability these are usually low probability –– high high exposure/high consequence events; the focus is within the plant exposure/high consequence events; the focus is within the plant boundaries boundaries Health Risks Health Risks –– these are high probability these are high probability –– low exposure/low low exposure/low consequence (or latent consequence) events; the focus here is consequence (or latent consequence) events; the focus here is occupational health occupational health Ecological/Environmental Risks Ecological/Environmental Risks –– these are high probability these are high probability ––low exposure/low consequence (or latent consequence) events; low exposure/low consequence (or latent consequence) events; the focus is site emissions the focus is site emissions –– both local and at great distances both local and at great distances Public Welfare/Goodwill Risks Public Welfare/Goodwill Risks –– this addresses the community this addresses the community or public perception of an organization; a negative impression or public perception of an organization; a negative impression can lead to a negative impact on sales or negative goodwill fromcan lead to a negative impact on sales or negative goodwill fromthe communitythe communityFinancial Risks Financial Risks –– this addresses both short term and long term this addresses both short term and long term property and financial losses; in essence property and financial losses; in essence –– the business case for the business case for risk managementrisk management

Safety Health Environment

Hazard Identification:Materials involved, quantities, reactivity, initiating events

Data Analysis:MSDS, and quantities/concentrations of chemicals

Problem formulation:Contaminants, and their effect on flora and fauna

Probability of causes:Likelihood of initiating events and propagating events

Exposure Assessment:Pathways and routes for the chemical to enter (exposure rates and time)

Exposure Assessment:Pathways and routes for the chemical to enter (exposure concentrations)

Consequence Analysis:Nature, magnitude and probability of adverse effects (fires, explosions, and their impact on receptors)

Dose-Response:Relationship between dose and adverse health effect

Toxicity Assessment:Relationship between chemical exposure and the impact on the environment

Risk Evaluation:Integration of probabilities and consequences

Risk Characterization:Integration of toxicity and exposure data (with uncertainty analysis)

Risk Characterization:Integration of toxicity and exposure data (with uncertainty analysis)

Fatalities, injuries, economic costs

Individual and population risks Ecosystem and habitat risks

Risk AcceptabilityRisk Acceptability

The The ““ZeroZero--Risk PrincipleRisk Principle”” -- no risk can be tolerated no risk can be tolerated (regardless of its magnitude or the relative benefits)(regardless of its magnitude or the relative benefits)

The world is not a zero risk environment The world is not a zero risk environment –– is it better to is it better to incur a small risk in order to avoid a larger risk? incur a small risk in order to avoid a larger risk?

The The ““De De MinimisMinimis PrinciplePrinciple”” -- some levels of risk are so some levels of risk are so trivial that they are not worth worrying about. trivial that they are not worth worrying about.

often assumed as a lifetime risk of 1 x 10often assumed as a lifetime risk of 1 x 10--66. .

The The ““De De ManifestisManifestis PrinciplePrinciple”” -- some risks are so some risks are so obvious that they must be controlled regardless of cost.obvious that they must be controlled regardless of cost.

a lifetime risk of 1 x 10a lifetime risk of 1 x 10--33..