Process Hazard Analysis DOW Fire & Explosion Index ChE 258 Chemical Process Safety University of...

Process Hazard Process Hazard AnalysisAnalysis

DOW Fire & Explosion DOW Fire & Explosion IndexIndex

ChE 258ChE 258

Chemical Process Chemical Process SafetySafety

University of Missouri University of Missouri - Rolla- Rolla


SummarySummary

Originated due to poor loss Originated due to poor loss (accident) record in 1966(accident) record in 1966

One of the first “chemical plant” One of the first “chemical plant” hazard analysis systemshazard analysis systems

Unique FeaturesUnique Features

– Maximum Probable Property Maximum Probable Property DamageDamage

– Maximum Probable Days Maximum Probable Days OutageOutage

Continues to be upgraded in use Continues to be upgraded in use and applicationand application

Fill out like a “Tax Form”Fill out like a “Tax Form”


F & EIF & EI Uses material factors that relate Uses material factors that relate

to reactivity and flammabilityto reactivity and flammability

Identifies equipment that can Identifies equipment that can present a flammable or present a flammable or explosive hazardexplosive hazard

Suggests approaches to control Suggests approaches to control a hazarda hazard

Useful in determining plant Useful in determining plant layout and separation between layout and separation between vesselsvessels

Requires engineering Requires engineering judgementjudgement

Is not a perfect toolIs not a perfect tool

Is a useful toolIs a useful tool


QUANTIFYQUANTIFY

IDENTIFYIDENTIFY

COMMUNICATCOMMUNICATEE

The expected damage The expected damage of potential fire & of potential fire & explosion incidents in explosion incidents in realistic termsrealistic terms

Equipment that would Equipment that would likely contribute to likely contribute to the creation or the creation or escalation of an escalation of an incidentincident

The fire & explosion The fire & explosion potential to design potential to design teams and plant teams and plant personnelpersonnel


Material FactorMaterial Factor– Measure of Reactivity and Measure of Reactivity and

FlammabilityFlammability General Process HazardsGeneral Process Hazards

– Play a primary role in Play a primary role in determining the magnitude determining the magnitude of a loss incidentof a loss incident

Special Process HazardsSpecial Process Hazards– Contribute to the probability Contribute to the probability

of a loss incidentof a loss incident Fire & Explosion IndexFire & Explosion Index

– A measure of the relative A measure of the relative hazard and relates to an hazard and relates to an exposure radiusexposure radius


LOSS CONTROL CREDITSLOSS CONTROL CREDITS

Are features that have Are features that have proved beneficial in proved beneficial in preventing serious preventing serious incidents and reducing incidents and reducing the magnitude of a the magnitude of a particular incidentparticular incident

** Process ControlProcess Control

** Material IsolationMaterial Isolation

** Fire ProtectionFire Protection


Actual Maximum Probable Actual Maximum Probable Property Property DamageDamage

Represents the property damage Represents the property damage that could result from an incident of that could result from an incident of reasonable magnitude with adequate reasonable magnitude with adequate functioning of protective equipmentfunctioning of protective equipment

Maximum Probable Maximum Probable Days Days OutageOutageTime required to rebuild the plant to Time required to rebuild the plant to its original capacityits original capacity

Business InterruptionBusiness InterruptionThe lost profit to the company due to The lost profit to the company due to

an incidentan incident

DOW Fire & Explosion IndexDOW Fire & Explosion Index

Items Required to Develop Items Required to Develop an F & EIan F & EI

1. Accurate Plot Plan for an 1. Accurate Plot Plan for an existing plantexisting plant

2. Preliminary Plot Plan for a 2. Preliminary Plot Plan for a new plantnew plant

3. Process Flow Sheet3. Process Flow Sheet

4. F & EI Hazard 4. F & EI Hazard classification guideclassification guide

5. F & EI form5. F & EI form


IDENTIFY PERTINENT PROCESS UNITIDENTIFY PERTINENT PROCESS UNIT

(An item of equipment that could impact the (An item of equipment that could impact the process from a safety & loss prevention process from a safety & loss prevention

standpoint)standpoint)

* Chemical Energy Potential (Material * Chemical Energy Potential (Material Factor)Factor)

* Quantity of hazardous materials in * Quantity of hazardous materials in the process unitthe process unit

* Capital density* Capital density

* Process pressure and temperature* Process pressure and temperature

* Past history of problems* Past history of problems

Not all unit operation need to be analyzed. Not all unit operation need to be analyzed.

Knowledge of the process is essentialKnowledge of the process is essential


MATERIAL FACTORMATERIAL FACTOR

* Measure of the * Measure of the flammability (Nflammability (NFF) and ) and reactivity (Nreactivity (NRR) of a ) of a materialmaterial

* Material factor adjusted * Material factor adjusted for process conditionsfor process conditions

-- Flash PointFlash Point

-- Boiling PointBoiling Point


CONTRIBUTING HAZARD CONTRIBUTING HAZARD FACTORSFACTORS

Evaluate the process unit to Evaluate the process unit to eliminate over estimating eliminate over estimating penaltiespenalties

** General Process Hazards General Process Hazards (F(F11))

** Special Process Hazards Special Process Hazards (F(F22))

DOW Fire & Explosion IndexDOW Fire & Explosion IndexGENERAL PROCESS HAZARDSGENERAL PROCESS HAZARDS

FF11

Penalties for:Penalties for:

Exothermic/EndothermicExothermic/Endothermic

Material Handling & TransferMaterial Handling & Transfer

Enclosed processesEnclosed processes

AccessAccess

Drainage and spill controlDrainage and spill control

F & EI workbook has various penaltiesF & EI workbook has various penalties

DOW Fire & Explosion IndexDOW Fire & Explosion IndexSPECIAL PROCESS HAZARDSSPECIAL PROCESS HAZARDS

FF22

Penalties for:Penalties for:Toxic materials (0.2 x NToxic materials (0.2 x NHH))

Sub-atmospheric pressure Sub-atmospheric pressure (P<500mHg, 0.5)(P<500mHg, 0.5)

Dust explosionsDust explosions

Operating in flammable range Operating in flammable range

Low temperature operationLow temperature operation

Corrosion & Erosion Corrosion & Erosion

LeakageLeakage

Rotating equipmentRotating equipment

F & EI workbook has various penaltiesF & EI workbook has various penalties


SPECIAL PROCESS HAZARDSSPECIAL PROCESS HAZARDS

FF22

Pressure PenaltyPressure Penalty

DOW Fire & Explosion IndexDOW Fire & Explosion IndexSPECIAL PROCESS HAZARDSSPECIAL PROCESS HAZARDS

FF22

Quantity of Quantity of Flammable/Unstable materialFlammable/Unstable material

Separate figures for process, storage and solidsSeparate figures for process, storage and solids


SPECIAL PROCESS HAZARDSSPECIAL PROCESS HAZARDS

FF22

Use of fired equipmentUse of fired equipment

Curve A-1 Release above flash point or Curve A-1 Release above flash point or combustible dustcombustible dust

Curve A-2 Released above boiling pointCurve A-2 Released above boiling point


UNIT HAZARD FACTOR (F3)UNIT HAZARD FACTOR (F3)

FF33 = F = F11 X F X F22

F & EI = Material Factor X F & EI = Material Factor X FF33


F & EI USED TO F & EI USED TO DETERMINEDETERMINE

An area having a potential An area having a potential for impact from a for impact from a flammable or over flammable or over pressure eventpressure event


F & EIF & EI

1 - 601 - 60

61 - 9661 - 96

97 - 12797 - 127

128128** - 158 - 158

159+159+

* * Trigger for more detailed PHATrigger for more detailed PHA

Degree of Degree of HazardHazard

LightLight

ModerateModerate

IntermediateIntermediate

HeavyHeavy

SevereSevere

Area of ExposureArea of Exposure

Exposure radius from empirical Exposure radius from empirical relationship relationship

Determined from spills of flammable materials 3 Determined from spills of flammable materials 3 in. deep as well as potential vapor air mixturesin. deep as well as potential vapor air mixtures


Volume of ExposureVolume of Exposure

Calculate volume as a cylinder Calculate volume as a cylinder with height equal to radius with height equal to radius

Determine replacement value of Determine replacement value of equipment in the area (volume)equipment in the area (volume)


Damage FactorDamage Factor

Determine damage factor from Determine damage factor from empirical relationship of Unit empirical relationship of Unit Hazard (FHazard (F33) and Material ) and Material Factor (MF) Factor (MF)


BASEBASE MAXIMUM PROBABLE MAXIMUM PROBABLE PROPERTY DAMAGEPROPERTY DAMAGE

Base Maximum Probable Base Maximum Probable Property Damage (Base MPPD)Property Damage (Base MPPD)

==

Value of the area of exposureValue of the area of exposure

XX

Damage Factor Damage Factor



LOSS CONTROL CREDIT LOSS CONTROL CREDIT FACTORSFACTORS

F & EI workbook has various creditsF & EI workbook has various credits

ACTUALACTUAL MAXIMUM MAXIMUM PROBABLE PROPERTY PROBABLE PROPERTY

DAMAGEDAMAGE

Actual Maximum Probable Actual Maximum Probable Property Damage (Actual Property Damage (Actual

MPPD)MPPD)

==

Base MPPDBase MPPD

XX

Credit Factor Credit Factor


MAXIMUM PROBABLE DAYS MAXIMUM PROBABLE DAYS OUTAGE (MPDO)OUTAGE (MPDO)

Maximum Probable Days Maximum Probable Days Outage (MPDO) determined Outage (MPDO) determined

empirically from actual MPPDempirically from actual MPPD


BUSINESS INTERRUPTIONBUSINESS INTERRUPTION

Business Interruption (BI)Business Interruption (BI)

==

Maximum Probable Days Maximum Probable Days Outage (MPDO)Outage (MPDO)

XX

{Lost Profit before tax/day{Lost Profit before tax/day

++

Fixed Cost/day} Fixed Cost/day}


RISK ANALYSISRISK ANALYSIS


WHAT CAN I DO TO LOWER WHAT CAN I DO TO LOWER THE RISK?THE RISK?

* * Reduce the Hazards (most impact)Reduce the Hazards (most impact)

* Add Loss Control Features (Least * Add Loss Control Features (Least impact)impact)

* Increase spacing (plant layout)* Increase spacing (plant layout)

It is more effective to reduce the It is more effective to reduce the hazards early in the project than to hazards early in the project than to add loss control features late in the add loss control features late in the projectproject

The system makes us quantify the risk The system makes us quantify the risk and suggests ways to reduce the riskand suggests ways to reduce the risk


The DOW F & EI system The DOW F & EI system

challenges you to challenges you to

determine how much determine how much

risk you are willing to risk you are willing to

accept.accept.


Determine Material Factor Determine Material Factor accounting for high operating accounting for high operating

temperaturetemperature


Example ProblemExample Problem

Fill out like it is a “Tax Fill out like it is a “Tax Form”Form”

Begin with the corrected Begin with the corrected Material FactorMaterial Factor



General Process Hazards General Process Hazards according to F & EI according to F & EI workbook. If it does not workbook. If it does not apply enter zeroapply enter zero



For Pressures less that 1000 For Pressures less that 1000 psig use Figure 2psig use Figure 2



Determine total BTU’s in Determine total BTU’s in system and determine system and determine penalty factor from figure 3. penalty factor from figure 3.



Determine Radius of Exposure Determine Radius of Exposure from the calculated F & EIfrom the calculated F & EI



Determine area exposed to Determine area exposed to the fire and explosion and the fire and explosion and determine the value of determine the value of the equipmentthe equipment



Determine the Damage Factor Determine the Damage Factor from the F &EI and Unit Hazard from the F &EI and Unit Hazard Factor (FFactor (F33). For F). For F33 greater than greater than 8 use the F8 use the F33 = 8 curve = 8 curve



Determine the Base Maximum Determine the Base Maximum Probable Property DamageProbable Property Damage

(Base MPPF)(Base MPPF)



Determine the Loss Control Credit Determine the Loss Control Credit FactorsFactors



Calculate Actual Maximum Calculate Actual Maximum Probable Property Damage (base Probable Property Damage (base MPPD x Credit Factor). Use MPPD x Credit Factor). Use actual MPPD to find Maximum actual MPPD to find Maximum Probable Days OutageProbable Days Outage



Process Hazard Analysis DOW Fire & Explosion Index ChE 258 Chemical Process Safety University of...

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