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# PICK-U P DATE : 3/15/200 7 BO X \3L 

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tO Ste p 2 : FO R ASR C INTERNA

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# EP A DOCKE T ID : 300PQ-EH Q 1 ) 300PQ-EHQ-2-L3 1 3 ) 300PQ-EHQ-2-L3 3 5 ) 300PQ-EHQ-2-L3 5 7 ) 300PQ-EHQ-2-L3 7 9 ) SOOPQzEHQzZ- l 11 ) (|00PQ-EHQ-7-> i 13 ) 15 ) 17 ) 19 ) 21 ) 23 ) 25 ) 27 ) 29 ) 31 ) 33 ) 35 ) 37 ) 39 ) 2 ) 4 ) 6 ) 8 ) 10 ) 12 ) 14 ) 16 ) 18 ) 20 ) 22 ) 24 ) 26 ) 28 ) 30 ) 32 ) 34 ) 36 ) 38 ) 40 ) Ste p 3 : FO R ASR C INTERNA L US E ONL Y CD : OA : / 

# 300PQ-EHQ-2-L3 2 300PQ-EHQ-2-L3 4 300PQ-EHQ-2-L3 6 300PQ-EHQ-2-L3 8 300PQ-EHQ-7- 2

Ste p 1 : FO R ASR

C INTERNA L US E ONL Y Are ther e mor e document s fo r thi s Docke t i n anothe r box ? *YE S / N O *Fil l ou t Continuatio n Shee t an d go t o Ste p 2 Interna l SFUN D Bo

x Numbe r Initials/Date : 3/9/200 7 H.T . 4 7 O F 28 3P. 2 

# 2dcf?Q-EY\§>- IS

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# CONSEQUENCE S O F ACCIDENT S INVOLVIN G

FLAMMABL E GASE S AN D LIQUID S

Jul y 5 , 199 0

£ £P. 3

T , 11 TABL E OF CONTENT

S (continued ) Pag e
8. 0 Modellin g Results 1 3 8. 1 Vapo r Clou

d Explosio n Results 1 3 8. 2 Vapo r Cloud Fire Result s 1 7 8. 3 BLEV E Result

s 2 3 8. 4 Poo l Fire Result

s 2 7 8. 5 Je tFire Result

s 3 2 9. 0 Findings 3 2 Reference s 3 8 Appendi x A Additiona

l Informatio

n o n Classification System s an d AccidentHistorie s for Flammable Chemical

s 4 0 A l Classification System s for Flammable Chemical s 4 1 A1. 1 Definition s Relate d t o Classificatio n o f Flammable Substances 4 1 A1. 2 DO T Classifications 4 1 A1. 3 NFP

A Classifications 4 2 A1. 4 EE C Indicativ

e Criteri a 4 3 A 2 OSHA Regulation s fo r Servic e Station s 4 3 A 3 Additiona

l Informatio

n fro m th e Acute Hazardou

s Event s Dat a Bas e 4 3 Appendi x B . Methodologie s fo

r Calculation o f

Consequenc

e Distance s 4 8 B. 1 WHAZA N 4 9 B. 2 ARCHI E 5 7 B3 Yello w Boo k 6 7 B. 4 AIChE-Sponsored Course Materials 7 7 B. 5 Green Boo k 8 1 Appendi x C . Hazar

d Criteri a 8 4 C l Explosio n Overpressur e 85 Ci. l Damag

e an d Injur y fro m BlastWave

s 8 5 C1. 2 Distance Determinatio n fo r Differen tOverpressure

s 9 3 

# tflP. 4

r. > 1 TABL E OF CONTENT

S Page 1. 0 Introduction 1 2. 0 Backgroun

d 1 3. 0 Existing Classification Systems , Regulations , an d Code s 2 3. 1 DO T Classifications 3 3. 2 NFP A Classification System

s 3 3. 3 EE C Classification Schem e 3 3. 4 Regulation s an

d Codes Applicabl e t o Flammable Chemicals 3 4. 0 PastFir e an

d Explosio n Incident

s Involving Flammabl e Chemicals 4 5. 0 AccidentConsequence Modellin g 4 5. 1 WHAZA N Methodolog y 5 5. 2 ARCHIE Methodolog y 5 5 3 Th e "Yello

w Book " Methodolog

y 6 5. 4 AIChE-Sponsored Cours e Material s 6 5. 5 Th e "Gree

n Book " Methodolog

y 6 6. 0 Consequence Analysi s Approac h 6 6. 1 AccidentScenario s 7 6.1. 1 Vapo r Clou

d Explosion s 7 6.1. 2 Vapo r Clou

d Fires 9 6.1. 3 BLEVE s an

d Fireball s 9 6.1. 4 Poo l Fires 1 0 6.1. 5 Je tFires 1 0 6. 2 Chemicals , Quantities , an d Condition s Use d i n Modellin g 1 0 6.2. 1 Chemical

s an d Quantitie s Chose n for Modellin g 1 0 6.2. 2 Instantaneous an

d Prolonge d Release s 1 1 6.2. 3 Initia

l Condition s Prior t o Releas e 1 1 6.1 4 Meteorolog

y 1 1 7. 0 Hazar

d Criteri a 1 2 7. 1 Hazar

d Criteri a fo r Vapo r Cloud Explosion s 1 2 7. 2 Hazar

d Criteri a fo r Vapo r Cloud Fire s 1 2 7. 3 Hazar

d Criteri a fo r BLEVEs , Poo l Fires , an d JetFires 1 3 

# •pP. 5

I V LIS T OF EXHIBITS ExhibitPag e 1 Chemical s Know

n t o Hav e Bee n Involved i n Vapo r Clou d Explosion s 7 2 Distance s fo r Vapo r Cloud Explosion s o f Fou r Liquefied Gase s fo r Instantaneou s Release s o f 1,00 0 t o 180,00 0 Pound s Determined Usin g Fractio n Flashed , WHAZA N Stand-Alon e Model 1 4 3 Quantit

y Release d Versu s Distanc e for Vapo r Qou d Explosions , Instantaneous Release s 1 6 4 Distance s fo r Vapo r Qou d Fires from Evaporating Pool s fro m Instantaneous Releases , Moderat e Meteorology , Determined Usin g WHAZA N 1 8 5 Quantit

y Release d Versu s Distanc e fo r Vapo r Qou d Fires , Instantaneou s Releases , Moderat e Meteorology 2 2 6 Distance s for BLEVE s for Instantaneous Release s o f 1,00 0 t o 180,000 Pounds , Determine d Usin g WHAZA N 2 4 7 Quantit

y Release d Versu s Distanc e for BLEVEs , Instantaneou s Release s 2 6 8 Distance s for Poo l Fire s for Instantaneous Release s o f 1,00 0 t o 180,000 Pounds , Determine d Usin g WHAZA N 2 8 9 Quantit

y Release d Versus Distanc e fo r Poo l Fires , Instantaneou s Release s 3 1 1 0 Distance s fo r Je tFire s for Prolonged Release s o f 10,000 Pounds , Determine d Usin g WHAZA N 3 3 1 1 Flammable Gase s 3 4 1 2 Flammable , Volatil e Liquids 3 6 A- 1 Fir e an

d Explosio n Event

s Compare

d t o Al l Event

s i n Acut e Hazardou

s Event s Dat a Bas e . . 4 4 A- 2 Flammabl e Gase s an d Liquids Reporte d i n In-Plan tFires o r Explosions 4 6 C- l Huma

n Injuiy Criteria (Includes Injur y fro m Flying Glas s an

d Dire a Overpressur

e Effects ) . . 8 6 C- 2 Propert

y Damag e Criteria 8 8 C-3 Lethalit

y Curve s 9 1 C- 4 Lethalit

y an d Injur y Curve s 9 1 C- 5 Ai r Blas tCriteri

a for Personne

l Standin g i n th e Ope

n .. ; 9 2 C- 6 Hazar

d Criteri a Compariso

n fo r Vapo r Clou

d Explosion s fo

r Instantaneou

s Release s o f 100,00 0 Pound s 9 4 C-7 Hazar

d Criteria Comparison for Vapo r Cloud Fire s fo r Evaporatin

g Pool s Fro m Instantaneous Releases , Moderat e Meteorolog

y 9 5 C-8 Huma

n Injur y Criteri a (Therma

l Radiatio n Effect

s o n Bar e Skin ) 9 7 

# 1P. 6

U l TABL E OF CONTENTS (continued ) l_ae e
C 2 Flammabilit

y Limit s 9 3 C 3 Hea tRadiatio n 9 6 C3. 1 HeatRadiatio n Level s Causin g Death an

d Injuiy 9 6 C3. 2 Distanc e Determinatio n for DifferentHeatRadiatio n Level s 9 9 C3.2. 1 BLEVE s 9 9 C3.2. 2 Poo l Fire s 9 9 C 4 Reference s 10 2 Appendi x D . Comparison o f

Results o f

Modellin g b

y DifferentMethod s an

d Results o f

Vaiyin g Releas e Scenario s an d Meteorologica

l Condition s 10 3 D. l Vapo r Qou d Explosio n Results 104 D. 2 Vapo r Qou d Fire Result s 104 D 3 BLEV E Results 10 6 D. 4 Poo l Fire Results 106 D. 5 JetFire Results 10 7 D. 6 Instantaneous Releas e Compare d t o Prolonged Releas e 10 7 D. 7 Moderat

e Meteorology Compare

d t o WorstCas e Meteorology 10 7 Appendi x E . Input

s for Modellin g 10 8

^ ,P. 7

V US T O F EXHIBITS (continued ) ExhibitPage C- 9 Fatalit

y from Hea tExposure 9 8 C-1 0 Hazar

d Criteri a Comparison for BLEVEs , Instantaneous Release s 100 C-l l Hazar

d Criteri a Comparison fo

r Poo l Fires , Instantaneous Release s 10 1 D- 1 Results o f

Modellin g b

y Al l Method s 10 5 E- 1 Temperature

s an d Pressures Use d i n Scenario s 11 0 E- 2 Chemica

l Dat a Use d for Model s Il l E- 3 WHAZA N Modellin g Dat a fo r Instantaneous Releases , Moderat e Meteorolog

y 11 2 E- 4 WHAZA N Modellin g Data fo r Prolonge d Release s 11 3 E- 5 WHAZA N Modellin g Dat a for Instantaneous Releases , Wors tCas e Meteorolog

y 11 4 E- 6 ARCHIE Modellin g Dat a 11 5



# li OP. 8

CONSEQUENCES O

F ACCIDENT S INVOLVIN G FLAMMABL

E GASE S AN D LIQUID S

1. 0 Introductio n Whe n th e Emergenc

y Plannin g an

d Communit

y Righ tt o Kno

w Act , Titl e m o f

th e Superfun

d Amendment

s an d Reauthorizatio n Ac t(SARA) , wa s enacted i n 1986 , a lis to f extremel y hazardou

s substances (EHSs ) (formerl y th e lis to f

Acutel y Toxi c Chemicals published i n November o f 1985 ) wa s published under Sectio n 30 2 o f Titl e H L Sectio n 30 2 require

s a fadlit y tha tha s a n EH S abov e it s threshol d plannin g quantit y (TPQ ) t o notif

y th e Stat e Emergenc

y Respons e Commission (SERC ) tha ti ti s subjec tt o th e requirement

s fo r emergenc

y planning . Th e origina

l lis to f EHS s wa s create d usin g onl y acut

e toxidt y criteria . Th e purpos e o f th e lis twa

s t o identif y thos e substance s that , i f acddentall y released , coul d caus e deat h o r seriou s irreversible healt h effect s fro m toxidty off-sit

e afte r a shor texposure . However, toxidt y i s no tth e ont

y hazar d pose d b y chemicals . SAR A state s tha tth e Administrato r ma

y revis e th e list , bu

tsuc h revisions "shal

l take int o accountth e toxidty , reactivity , volatility , dispersibility , combustibility , o r flammability o f a substance. " Th e purpos e o f

thi s repor

ti s t o asses s th e potentia l consequences o f

acddents involving flammable chemicals . A particula

r emphasi s i s place d o n assessin g th e impact s o f acddents o n communitie s neighborin g industria

l facilities . Th e genera

l approac h taken i n assessin g th e consequences o f potentia l acddents involvin

g flammable chemical s wa

s t o identif

y an d evaluate : 1 ) existin g listin g an d classificatio n systems , alon g wit h an y applicabl e criteria ; 2 ) existin g regulation s an d code s dealing wit

h flammable materials ; an d 3 ) historie s o f acddent s involvin g flammable materials . EPA' s evaluatio n i s discussed i n Section s 3 an d 4 . Non e o f th e abov e supplie d suffiden tinfonnatio n t o serv e EPA' s specifi c needs . I twas , therefore , dedde d t o model th e potential consequence s from acdden tscenario s involving flammable chemicals t o establis h physica l an d chemica l propertie s tha

tma y b e indicativ

e o f th e hazard

s associated wit

h thes e chemicals . Th e result

s o f th e consequenc e modellin g wer e the n analyzed . Th e modellin g i s discusse d i n Section s 5 throug h 8 . EPA' s analysi s o f

th e modellin g result

s i s discussed i n Sectio n 9 . 2. 0 Backgroun

d EP A originally develope d th e lis to f EHS s a s par to f th e Chemica

l Emergenc

y Preparedness Progra

m (CEPP) whic

h wa s designe d t o increas e publi c awarenes s o f chemica l hazard s i n communities an

d t o focu s effor to n emergenc

y planning . EP

A believe d tha

tcommunities neede d a starting pointan d intende d tha

t th e lis tdra

w attentio n t o th e substances an d facilitie s tha

tpos e th e mos timmediat e concer n base d o n toxidty from a

n emergenc

y planning an

d respons e perspective . EP A recognized an

d emphasized tha

tthere are ten s o f

thousand s o f

compound s an

d mixture s i n commerc

e tha tma y pos e a hazar

d under specifi c circumstance

s an d tha tthi s lis taddresse

d lethalit y an d seriou s irreversible healt h effect s assodate d wit

h acut e toxidty . Th e Agenc

y chos e lethalit

y becaus e i trepresent

s th e mos timmediat

e concer n i n a n emergenc y situation . Severa l commenter

s o n th e rulemakin

g fo r th e EH S lis tnote d tha

tphysical/chemica

l hazard s suc h as flammabilit

y o r explosivit

y ma y lead t o letha

l consequences . I

n a n offidal inquir

y t o th e Agenc

y i n 1987 , Senato r Fran

k Lautenbur

g als o note d concer

n for hazard

s othe r tha

n toxidt y an d aske d tha tEP A focu s o n othe r hazards . Th e Agenc y agree d an d note d it s intentt o evaluat

e hazard s othe r tha

n toxidt y i n th e future . A Physical/Chemica

l Criteri a Workgrou

p (P/ C Workgroup) wa

s forme d atEP A t o addres

s th e concerns raised b y Senato r Lautenbur

g an d others an

d t o focu s o n th e proble

m o f identifyin g materials which ar

e hazardou s based upo n thei r physical/chemica l properties an

d coul d thereby b e candidat e EHSs . Th e Workgrou

p initiall y considere d th e hazard s referre d t o i n th e Ac tan

d determine

d tha tthe y fel l int o tw o genera l categories : hazard

s related t o toxi c properties an d hazard s related t o physical/chemica l properties . Th e characteristic

s o f reactivity , volatility , dispersibility , combustibility , an d flammability, mentione d i n th e 

# ) 4P. 9

Act , ar e relate d t o a variet

y o f physical/chemica

l properties ; th e Workgrou p chos e t o focus o n th e physical/chemica

l propertie s thatlea d t o th e greates tpotential hazard s t o people . Hazard

s assodate d wit

h physical/chemica

l propertie s ar

e primaril y based o n tw o phenomena tha tca n caus e seriou s persona

l injui y o r death . Thes e phenomen a ar e th e resul to f th e releas e o f

energ y from highly reactiv e o r flammable chemical s an

d ar e identifie d as overpressures from blas twave s an d therma l radiatio n from fires. Overpressure

s resul tfrom nearl

y instantaneou s energ

y release , o r detonation , whil e therma l energ y i s released durin

g combustion , whic

h occur s more slowly . Sinc e explosiv e chemical s are highl y reactive substances tha

tca n detonat e an d creat e overpressures , an

d flammable chemical s ca n bur n an d produce therma l radiation , th e Workgrou p focuse d o n explosive s an d flammable chemical s a s chemical s o f concern . Th e P/ C Workgrou

p electe d firstt o investigat e wha tsubstance s mighthave bee n identifie d an d wha t criteria mightalread

y b e i n us e b

y othe r organization s t o characterize hazardou s chemical s an

d t o determin e whethe r thes e criteria migh tmee tEPA' s needs . Criteri a wer e investigate d from man y organizations includin g th e Nationa l Fire Protectio n Assodatio n (NFPA) , th e Unite d State s Departmen t o f Transportation (DOT) , th e Occupationa l Safet y an d Healt h Administratio n (OSHA) , an d th e Europea

n Economi c Communit

y (EEC) . Th e workgrou

p initiall y sough tt o evaluat e an d possibl y us e th e criteri a from thes e othe r organization s t o develo p option s for addin g t o th e lis to f

EHS s chemical s tha

tar e flammabl

e o r explosive . Th e criteria fro m othe r organizations di

d no tappea

r t o b e base d o n th e consequence s o f a n acdden ti n term

s o f exposur e t o th e communit

y bu trathe r o n th e consequence s tha tcoul d occur withi n th e facilit y o r durin

g shipmen to f bulk material s o r durin

g fire-fighting. Fo r example , a n NFP A flammability ratin

g o f 4 i s assigned t o material s tha

twil l bur n readil y an d tha tdispers e readil

y o r vaporiz e rapidl

y o r completel y a t ambien tconditions . Thi s i s importan tt o fire-fighters approachin g a fire involvin g a flammabl e materia l bu tgive s littl e indicatio n o f th e impac

to n a communit

y fro m a n acdden tthattake s plac e insid e a n industria l facility . Th e P/ C Workgrou

p determine

d tha ta n evaluatio n o f

th e impact

s o f acddents involving substances tha t ma y b e hazardou

s t o th e communit

y becaus e o f

certai n physical/chemica

l propertie s wa

s necessary . Suc

h a n evaluatio n woul d hel p t o develo p th e criteria tha twoul d identif

y chemical s tha

tshoul d b e considere d extremel y hazardou

s an d therefor e o f concer n for communit

y emergenc

y respons e planning efforts . On e approac h wa s t o model acddents involvin g flammable chemical s an d t o analyze th e resultin g dat a i n order t o establis h a correlatio n between th e severit y o f acdden tconsequence s t o th e communit y an d physical/chemica

l propertie s relate d t o th e consequences . Thi s approac

h i s similar t o th e approac h take n t o establis h th e TPQ s fo r th e Sectio n 30 2 EHS s liste d based o n toxidt

y criteria . Thes e TPQ s wer e establishe d b

y assumin g a n acdden tscenario , a los s o f containmento f

a specifi c toxi c chemical , an d the n estimatin g th e dispersio n potential o f eac h chemical . A n inde x valu e base d o n th e dispersio n potential an d toxidty wa

s use d t o ran

k th e chemicals , an

d chemical s were assigned t o TP Q categorie s according t o thei r ranking. Th e workgrou

p electe d t o segregat

e th e chemical s int o separat e categorie s fo

r flammables, explosives , an d reactives for purposes o f

analysi s an d possibl e regulatio n eve n thoug h i twa s recognized tha

tthere ma

y b e overla p o f th e consequences ; e.g. , a detonatio n o f a flammable materia

l ma y yiel d th e same result

s as a n explosio n o f

a commerda

l explosive . However , th e workgrou p wante d t o determine wha

tparameter

s distinguis h a n extremel

y hazardou

s flammable substanc e from al l othe r flammables, extremel y hazardou

s explosive s from al l othe r explosives , an d s o on . Thi s repor

tfocuses o n flammable gase s an d liquids . Separat e document

s wil l address th e consequence s o f acddents involving commerda l an d non-commerdal explosive s an

d reactive chemicals . 3. 0 Existin g Classificatio n Systems , Regulations , an d Code s Ther e are man y organizations tha

thav e develope d lists , definitions , an d classification s relate d t o flammabl e chemicals , including DOT , NFP A EEC , OSH A an d EP A Som e organizations establis h thei r classifications wit

h qualitative description s bu tmos tclassifications ar

e base d o n physical/chemica

l 

# 15

"P.1 0

-3 - properties , usuall

y flash poin tan

d boilin g poin tNon e o f thes e classification system s appeare d t o b e primaril y base d o n potentia l hazard s t o th e communit

y from inddents involving release s o f flammable chemical s from fixed facilities ; therefore EPA dedde d tha tnon e o f thes e systems wa

s appropriat

e o r specifically applicabl e t o EPA' s regulator y needs . Th e system s examine d are described briefl

y i n th e followin g sections ; more detai l i s presente d i n Appendi x A 3. 1 DO T Classification s DO T classifie s flammable material s for shippin g purpose s unde r 4 9 CF R 172 . Thi s regulatio n list s material s DO T regard

s as hazardou

s for purpose s o f

transportation an

d prescribe

s requirement

s for shippin g papers , package marking, labeling , vehicl e placarding , an d type s o f container s an d safet y device s tha tmustb e use d t o transpor ta flammable material . Detail s o f th e DO T classifications for flammabl e material s are found i n Appendix A Th e DO T hazar

d classification s ar e base

d o n maintaining safet

y durin g transport

, give n th e rang

e o f ambien tcondition s possible . Th e consequence s i n term s o f "firs tresponse " t o acddents involvin g thes e material s are addresse

d i n DOT s Emergenc

y Respons e Guidebook . Thi s guid e detail s generi c isolatio n distances , recommended fire-fighting techniques , an d othe r initia

l emergenc

y action s for inddent s involvin g thes e substances . However , DO T focuse s o n transportatio n safet y rathe r tha n hazard s from fixed sites . 3. 2 NFP A Classificatio n System s Th e NFP A has a rating scal e o f 0 t o 4 , where 0 represent s th e lowes tdegree o f

flammability, fo r purpose s o f fire-fighting an

d fire prevention . Th e rating s ar e usuall y note d o n Materia

l Safet y Dat a Sheets (MSDSs ) an d are include d i n a standar d tha tapplie s t o facilitie s for manufacturing , storage , o r us e df

hazardou s materials . Approximatel

y 1,50 0 chemical s hav

e bee n assigned NFP

A ratings . Th e classification s ar e designe d t o give "

a genera l ide a o f th e inheren

thazard s o f an y materia l an d th e order o f

severit y o f thes e hazard s as the y relat e t o fir e prevention , exposur

e an d control " (NFP

A 1984) . NFP A ha s als o develope d a cod e (NFPA 30 , Flammable an d Combustibl

e Liquid s Code ) concernin g flammable an

d combustibl e liquid s whic h i s par to f th e Nationa

l Fire Cod

e an d i s specificall

y intende d t o b e referenced b

y publi c authoritie s i n laws , ordinances , regulations , an d administrativ

e orders . I twa

s originally written as a model muniripa l ordinanc

e for storing , handling , an d usin g flammable liquid s at fixed facilities . Thi s cod e include s classification s based o n flas h poin tan

d boilin g poin tTh e NFPA flammability rating

s an d classification s from th e NFP A cod e ar e discusse d furthe r i n Appendi

x A 3 3 EE C Classificatio n Schem e Th e EE C published a Council Directiv e o n June 24,1982 , "concerne d wit h th e preventio n o f

majo r acddents whic

h mightresul tfrom certai n industria l activitie s an

d wit h th e limitatio n o f

thei r consequence s for ma n an d th e environment " (EE C 1982) . Th e directive includes a lis to f toxi c an d explosiv e chemical s an d severa l categorie s o f

flammable chemicals ; th e flammable categorie s ar e defined b

y "Indicativ

e Criteria. " Facilitie s tha

thav e liste d chemicals i n quantitie s greate r tha n a specified threshol d amountar e require d t o repor

tan d mee ta variet

y o f condition s including performin g hazard s analyses an

d preparing emergenc y plans . Th e threshold s for th e flammable categorie s ar e 20 0 metri c ton s (440,00 0 pounds ) for flammable gase s an

d flammable liquid s unde r hazardou

s processing conditions , an d 50,00 0 metri c ton s (1. 1 millio n pounds ) fo

r othe r highl

y flammable liquids . Th e indicativ e criteri a related t o flammability ar e discussed i n Appendi

x A 3. 4 Regulation s an

d Code s Applicable to Flammable Chemicals Severa l agende s regulat

e flammable chemicals . OSH A regulates flammable an d combustibl e liquid s (2 9 CF R 1910.106) , wit

h handling an

d storage requirement

s an d spedfication s fo

r storag e tanks . Specifi c requirement

s ar e included for bul

k plants , servic

e stations , processing plants , refineries , chemica l plants , an d distilleries . I

n addition , there are spedfi c regulation s dealin g wit h acetylen e (2 9 CFR 1910.101) ,P.1 1

hydroge n (2 9 CF R 1910.102) , an

d liquefied petroleu

m gase s (2 9 CF

R 1910.110) . Flammable an d combustibl e liquid s ma

y als o b e regulated b

y state o r local governments ; e.g. , NFP A 30 , Flammabl e an

d Combustibl e liquid s Cod e (se e sectio n 3.2) , ma y b e adopte d o r incorporated int o law . DO T regulation s includ e shippin g requirement s for flammabl

e materials (4 9 CF

R 172 an d 173) . Al l o f

thes e regulation s are highl y specifi c an

d dea l wit h containers , pipes , an

d storage , handling , o r transfe r condition s i n specifie d circumstances ; however, non e i s directl y applicabl e fo

r EPA' s purposes . Gasolin e i s a flammable chemica l o f particula r interes tbecaus e o f

th e hig h volume s i n commerce an d th e man y location s wher

e i tma y b e found . Therefore , EP A investigate d th e regulation s for flammable chemical s wit

h additiona

l focus o n gasoline . Gasolin e i s no tregulated as a specia l cas e under an

y o f th e regulation s o r code s mentione d above . DOT s requirement s fo r gasolin e are similar t o thos e fo r othe r liquid s wit

h simila r properties , a s are NFPA' s recommendation s fo r gasoline . OSHA' s regulation s fb r service station s d o no tmentio n gasolin e specifically , bu trefer onl y t o flammable liquids . Thes e regulation s cove r th e storag e an d dispensing o f

flammable liquids , electrica l an d heatin g equipmenti n area s wit h flammable liquids , wast e handling , an

d fire extinguisher

s atservice stations . Further informatio n o n th e OSHA regulation s for flammabl e liquid s ma

y b e foun d i n Appendi

x A EPA' s review o f curren tregulations indicate s gasolin e i s no tconsidered a speda l case . Fuel s are no tincluded as hazardou s substances unde

r CERCLA ; "petroleum, includin g crude oi l o r an y fraction thereof

, ...natura l gas , natura

l ga s liquids , liquefied natura

l gas o r syntheti c ga

s usabl e for fue

l (o r mixture s o f natura l gas an d suc h syntheti c gas) " ar

e no tincluded i n th e definitio n o f hazardou s substance s (4 0 CF R 300.6) . 4. 0 Pas tFir e an d Explosio n Inddent s Involving Flammable Chemical s Th e Acut e Hazardou

s Event s Dat a Bas e (AHE/DB ) wa

s develope d b

y EPA t o provide a historica l perspectiv e o n acddent

s tha tinvolv e release s o f

hazardou s substances i n th e Unite d State s (EP A 1988) . Th e 198 8 versio n o f

th e dat a bas e include s dat

a o n 5,82 7 inddent s tha

toccurre d betwee n th e 1960s an

d 198 7 (th e majorit

y o f th e inddent s appea

r t o hav e occune d i n th e 1980s) . Informatio n i n th e dat

a bas e i s from th e Nationa

l Respons e Center , pres s reports , an d severa l stat e offices . Thi s dat

a bas e wa s reviewed t o identif y acddents specificall

y involving flammable chemical s an d evaluat e th e consequence s o f

thes e acddents , i f

possible , i n term

s o f physical/chemica

l characteristic

s an d th e specifi c hazard

s pose d t o th e surroundin

g community . Fire an d explosio n inddents accoun tfo r abou t1 3 percen

to f th e tota l inddent s i n th e AHE/DB , butthe y accountfor nearl

y 9 2 percen

to f th e deaths an

d abou t3 6 percen

to f th e injuries reported . However , th e numbe r o f thes e death s an

d injuries thatoccurre

d on-sit e an

d th e numbe

r tha toccune d off-site canno tb e ascertained from th e dat

a base ; therefore , th e degree o f impac tthes e inddents ha

d o n th e surrounding communit y cannotb e accuratel

y determined . Additiona

l detail s an

d analyse s using th e dat

a from th e AHE/D B ma

y b e foun d i n Appendix A Sectio n A3 . Th e AHE/D B indicates tha tflammabl

e chemicals ar

e hazardous ; the

y hav e bee n involved i n numerou s acddent s tha

tresulted i n fire

s an d explosions , an

d thes e acddents le d t o man y death s an

d injuries . However , th e dat

a ar e no tsuffidentl y specifi c t o serv e as a basi s for identifyin

g chemical s thatma

y b e extremely hazardou

s base d o n thei r physical/chemica l properties . 5. 0 Acciden

tConsequenc

e Modelling Becaus e classificatio n method s an d regulator

y approache

s used b y othe r organizations di d no tappea r t o b e relate d t o hazard

s t o th e community , especially from acddents a tfixed facilities , an

d historica

l acdden t dat a appeare d t o b e inadequat

e a s a basis fo

r identifyin

g an d classifyin

g flammable chemicals , EPA dedde d t o us e modellin g techniques t o evaluat e potentia l hazard s t o th e communit

y fro m inddent s involvin g releas e o f flammable liquid s an

d gase s fro

m fixed sites . N o on e hazard s analysis model has bee n universall y accepted ; therefore , tw

o PC-base d model s an

d severa l method s involving manua l calculation s wer e use d fo r a singl e releas e quantit

y t o estimat

e consequence s o

f acddents involving flammabl e liquid s 

# nlP.1 2

-5 - an d gase s for comparison purposes . A s discussed i n th e followin g section , th e WHAZA N model wa s selecte d fo r us e i n th e extensiv e acdden tconsequenc e modellin g analysis . Th e models , approach , an d result s o f modellin g ar

e discussed i n th e followin g sections . EPA di d no t attemp tt o validat

e o r verif y th e model s use d no r t o evaluat e o r estimat

e thei r uncertainties ; th e result s obtaine d usin g th e various method s ar e presente d for comparison purpose s i n Appendi x D . I n general , th e variou s method s sho w reasonabl e agreemen ti n predicting consequence s for various acdden tscenario s an d hazar d criteri a levels . Additiona l informatio n o n eac

h o f th e model s i s presente d i n Appendi x B . Assumption s use d i n th e modellin g an d th e physical/chemica

l dat a required a s inputfor th e chemical s modelle d ar

e summarize

d i n Appendi

x E . 5. 1 WHAZA

N Methodolog

y Th e commerciall

y availabl e Worl

d Ban k Hazar d Analysi s (WHAZAN ) computer syste m i s a grou

p o f compute r program

s capabl e o f

performin

g quic k estimate s o f

th e possibl e hazardou

s consequence s o f acddenta l release s o f

toxi c and/o r flammable gase s o r liquids . I twa s develope d b

y Technic a Internationa

l Ltd . i n collaboratio n wit

h th e Worl

d Bank. Thes e programs , when combined , compris e model s for calculatin g th e consequence s o f differen ttype s o f chemica l releases . Th e model s deriv e thei r input

s from a dat a bas e whic

h contain s relevan

tpropertie s o f

som e hazardou

s chemicals . Th e user ca

n ad d chemical s an d propertie s t o th e dat

a base . A use r o f

WHAZA N ca

n eithe r ru

n on e o f th e model s individuall

y fo r calculatin g th e hazardou

s consequence s from a specifi c typ e o f releas e (stand-alon e models) , o r can link tw o o r more model s i n a wa y suc h tha toutput s fro m on e model ca

n b e used automaticall

y a s input s for anothe r model (linke d models) . Th e model s provid e information aboutfou r ke y areas : outflo w o f

th e chemica l from it s container , behavio r immediatel y afte r release , dispersio n afte

r release , an

d fires an d explosions . Man y differen tassumptions ar

e taken int o accoun

tb y WHAZA N when attempting t o predic tth e hazard

s resultin g from acddenta

l release s o f

th e chemical s contained within its dat a base . Assumption s ar

e made regardin g atmospheri c behavior an d acddental releas e rate

s o f various gase s an

d liquids . Thes e assume

d values , combine d wit

h chemical-specifi c inputvalues , allo w WHAZA N t o predic tth e hazardou

s consequence s o f

differen ttype s o f acddental releases . Th e WHAZA N mode l i s extensivel

y use d b y large internationa

l chemica l companie s an

d governmen

tagendes . I

n addition , thi s mode

l appear s t o b e mor

e chemical-specifi c tha

n th e othe r modellin g method s considered an d th e comparison o f

WHAZA N result

s wit h th e result

s usin g othe r method s showed reasonabl e agreemen tTherefore , WHAZA N wa s use d as th e primar

y metho d o f

consequenc e analysis fo

r flammable chemicals . Mor e detail s o n th e WHAZA N model ar e foun d i n Appendi

x B , Sectio n B.l . 5. 2 ARCHI

E Methodolog

y Acdden thazar

d assessmen

tan d consequenc e analysis procedure s hav e bee n incorporate

d int o a progra

m develope d fo

r th e Federa

l Emergenc

y Managemen

tAgenc y (FEMA) , DOT , an

d EPA , entitle d Automate d Resourc e for Chemica

l Hazar d Indden tEvaluatio n (ARCHIE) . Th e primar y purpos e o f

ARCHI E i s t o provid e emergenc

y personne

l wit h severa l integrated estimatio n method s tha tma y b e used t o asses s th e vapo r dispersion , fire , an

d explosio n impact

s assodate d wit

h episodi c discharge

s o f hazardou s material s int o th e environmen tTh e progra m i s als o intende d t o facilitat e a bette r understandin

g o f th e natur

e an d sequenc e o f

event s tha tma y follo w a n acdden tan

d th e resultin g consequences . Th e cor e o f

th e ARCHIE computer progra m i s a se to

f hazar d assessmen

tprocedure

s an d model s tha

tca n b e sequentially utilize d t o evaluat e consequence s o f

potentia l discharge

s o f hazardou s materia l an d thereby assis ti n th e developmento f a basi s for emergenc

y planning . ARCHIE ca

n hel p emergenc

y plannin g personnel understand : 1 ) th e natur e an d magnitude o f

hazard s posin g a threa

tt o thei r jurisdiction ; 2 ) th e sequenc e o f

event s tha tmus ttake plac e for thes e threat s t o b e realized ; an

d ultimatel

y 3 ) th e natur

e o f respons e action s tha

tma y b e necessar

y t o mitigat

e adverse impact

s upo n th e publi c an

d it s propert

y i n th e even to f a n emergency .P.1 3

Th e syste m contain s numerou

s model s fo

r evaluatin g differen

ttype s o f release s an

d thei r consequences , suc h as poo l fires , unconfine d vapor dou d explosions , fireballs , an d tan k overpressurization . More detail s aboutth e syste

m are presented i n Appendix. B , Sectio n B.2 . 5 3 Th e "Yello

w Book" Methodolog

y Th e Burea

u o f Industria l Safet y (TNO ) o f

th e Netherland s ha

s issue d a report , commissione d b y th e Directorate-Genera

l o f Labour , entitle d "Method

s for th e Calculation o f

th e Effect

s o f th e Escap e o f Dangerou s Material " (Marc h 9,1980) , als o know

n a s th e "Yello

w Book" . Equation s an

d calculatio n method s for estimatin g th e effect s o f severa l types o f acddents involving flammable liquid s an d gase s are presented . Som e o f

thes e method s were use d a s th e basi s fo r model s i n WHAZAN . Th e Yello w Boo k indude s calculation s for poo l fires, vapor clou d fires, an d vapor clou d explosion s for gases , an d poo l fires an d vapo r clou d fires fo

r liquids . Fo r gases , two differen tmethodologie s ar

e use d for vapo r dou d fires: th e flash fraction o f

eac h ga s i s modelled as a

n instantaneou s release ; th e non-flashed fraction i s modelle d a s a continuou s releas e from a n evaporatin

g pool . I n bot h cases , dispersio n as a neutrall y buoyan tclou d i s assumed . Th e flash fraction o f eac h ga s i s use d t o calculat

e th e vapo r clou d explosio n results . Sinc e ther e i s n o calculated flash fractio n fo r liquids , n o vapo r clou d explosio n result s appea r for liquids . Appendix B , Sectio n B 3 present

s detail s o f

th e calculation s tha

twer e used i n thi s analysis . SA AIChE-Sponsore

d Cours e Material s Th e America

n Institut e o f Chemica l Engineer

s (AIChE ) sponsored cours e materia l titled, "Method

s for Calculatio n o f

Fire an d Explosions Hazards " (1987) , present s equation s for calculatin g th e effect s o f severa l type s o f acddent s involving flammabl e liquid s an

d gases . Thi s materia

l i s a compendiu

m o f method s an

d algorithms dealing wit

h fires an d explosions , no ta straightforwar d approac

h t o determinin g consequence s o f

various acddentscenarios . Th e equation s used i n thi s analysis an d detail s o f

th e methodology ar

e presente d i n Appendi

x B , Sectio n B.4 . 5. 5 Th e "Gree

n Book" Methodolog

y EP A h i conjunctio n wit

h FEM A an d DOT , develope d th e "Technica l Guidanc e fo r Hazard s Analysis " (1987 ) t o provid e guidanc e t o local emergenc

y plannin g committee s (LEPCs) , local emergenc y agendes , an d communit

y group s i n assessing hazard s relate d t o potentia

l airborn e release s o f

extremel y hazardous substances liste d becaus e o f thei r toxidt

y unde r sectio n 30 2 o f

SAR A Titl e in . Thi s guidance , know n a s th e "Gree n Book, " provides methods fo r estimatin g chemica

l release s an

d dispersio n distances . Thes e method s were applie d t o th e airborn e dispersio n o f

vapo r cloud s o f

flammable liquid s an

d gase s t o estimat e distance s for vapor cloud fires . Se e Appendi x B , Sectio n B. 5 fo

r detail s o f

th e calculations . 6. 0 Consequence Analysi s Approac h Ther e ar e man y factor s tha taffec tth e severit

y o f th e consequence s o f

a n acdden tinvolvin g a flammable chemical . I

ti s impossibl e t o lis tal l o f thes e factors , espedall y thos e tha tar e site-specifi c (e.g. , characteristic

s o f terrain , loca

l micrometeorologica

l effect s suc h a s sligh twin

d shifts , nearb

y facilities , an

d population) . Th e input

s t o th e variou

s hazar d analysis model s used tha tma y hav e a n impac to n acdden t consequence s includ e th e following :

• Specifi c physical/chemica l propenie s o f

th e chemica

l involved (e.g. , volatilit

y an d heato f combustion) ;

• Th e quantit

y o f th e chemica

l involved ;

• Th e type o f

releas e (instantaneou s o r prolonged) ;P.1 4

• Th e initia

l condition s (temperatur

e an d pressure ) o f

th e chemica

l jus tprio r t o release ;

• Meteorology (particularl y whe n modellin g scenario s tha tinvolv e dispersion) . Thes e factor

s an d thei r relationshi p t o consequenc e modellin g ar e discusse d below . 6. 1 Acdden tScenario s Th e WHAZA N model (discussed i n Sectio n 5. 1 an d detaile d i n Appendi

x B , Sectio n B.1 ) wa

s applie d t o flammable liquid s an

d gase s t o determine th e distanc e tha tmigh tb e affede d for various type s o f acddents , usin g vaiyin g quantitie s release d an d various hazar

d criteria levels . Amon g th e literatur e source s examined , there appear

s t o b e a genera

l consensu s regardin

g th e types o f

acddent s i n whic

h flammable substances typically ar e involved . Th e acddents o f concer n includ e vapo r dou d explosions , vapo r clou d fires, Boilin g Liqui

d Expandin

g Vapo r Explosion s (BLEVEs) , poo l fires, an d je tfires. Eac

h o f thes e acdden ttypes i s describe

d below . 6.1. 1 Vapor Qou d Explosion s Volatil e materials ca

n for m vapor cloud s when the

y are release d i n a

n uncontrolle d manne

r from containmen

tvessels . Materials tha

tar e a televate d temperatures and/o r pressure s ar e particularl

y o f concern . Release d volatile , flammable materials ca n flash directl y int o th e vapo r stat e and/o r flow t o th e groun d an d for m a poo l o f

liqui d whic

h subsequentl

y evaporates t o for

m a vapo r cloud . Afte r a vapo r clou d i s formed , thre e things ca n happen : i tca

n dispers e an

d hav e n o fir e o r explosio n impac

to n neighborin g communities ; i tca n ignite an

d bur n (vapo r clou d fire); o r i tcan detonate o r explod e an d caus e hig h pressur e shoc k waves . Fo r a vapor clou d t o ignite an d bur n o r explod e it s concentratio n i n ai r mustb e withi n it s flammability limits . A vapor clou d fire o r explosio n i s mor e likely i f th e clou d i s confined , by , for example , a building . A n exemplar y lis to f chemical s tha

tar e know n t o hav e bee n involved i n vapo r clou d explosion s i s show n i n Exhibi t1 . Not e tha

t1 2 o f th e 15 chemicals liste d ar e gase s unde

r ambien tconditions . EXHIBI T 1 - CHEMICAL

S KNOW N T O HAV E BEE N INVOLVE

D I N VAPO

R CLOU D EXPLOSIONS

Chemica l Hydroge n Methane/LNG Ethylen e Propylen e Dimethy l Ether Propan e Viny l Chlorid e Isobutan e Isobutylen e Butadien e Ethylen e Oxid e Ethy l Chlorid e Gasolin e Hexan e Cyclohexan

e References : R.W . Prug h (1987 ) J . Skark a (1987 ) Boiling Poin

tCO -25 3 -16 1 -10 2 -46 -4 3 -4 2 -2 4 -1 4 -1 2

- 8 1 1 1 2 5 9 7 2 8 1



# e PP.1 5

Chemical s are vaporized muc h mor e rapidl

y b y boilin g than b

y evaporation ; therefore , chemical s wit h boilin g points belo w ambien ttemperatures volatiliz e ver y rapidl y afte r bein g spille d an

d are mor e likel y t o generat e high-mass cloud s than chemical s tha tboi l abov e ambien

ttemperatures . Chemicals thatare gase s atambien ttemperature

s therefore representa greater explosio n hazar d tha n les s volatil e chemical s wit h boilin g point

s greater tha

n ambien ttemperatures (liquid s an d solids) . According t o Prug

h (1987) , th e probabilit

y of a vapo r clou d explodin g appear s t o depend o n th e weigh to f flammable vapor i n th e clou d (Le. , th e quantit y i n th e clou d abov e th e LFL) . Prugh' s analysi s (base d o n actua l vapor Clou

d explosio n events ) indicate s tha tth e probabilit

y o f explosio n i s 5 0 percentwhen th e weigh to f flammabl e vapo r i s 90,00 0 kilogram s (200,00 0 pounds) ; th e probabilit y decreases wit

h decreasing weigh tBased o n a

n equatio n develope d b y Prugh , fo r vapo r cloud s containin g les s tha n 10,00 0 pound s o f flammabl e vapor , th e probabilit

y o f explosio n become s relatively lo w (approximatel y 7 percentfo r 10,00 0 pound s an

d les s tha n 1 percentfor 1,00

0 pounds) . Prugh' s probabilit y analysis considered onl y th e likelihoo d o f

a vapo r dou d explodin g followin g a release , no tth e likelihoo d thata releas e mightoccur . Th e America

n Petroleum Institut

e (API ) ha

s develope d recommended proces s hazar d managemen

t practices (including suc

h topic s a s safet

y reviews , hazard

s analyses , training , saf

e practices , an

d indden t investigation ) fo

r production an

d refining department

s (AP I Recommende d Practic

e 750) . Thi s document ha s a n appendi

x detailin g th e applicatio n o f th e recommended practice t o facilitie s tha thave th e potential t o releas e five ton s o f

ga s o r vapo r i n a perio d o f

a fe w minutes . Th e five-ton quantit y wa s chose n b

y AP I a s a reasonabl e threshol d o n th e basi s o f catastrophi c potential an d probabilit y o f explosion . Fo r a vapo r clou d containin g five ton s o f hydrocarbon, AP

I consider s th e probabilit

y o f explosio n t o b e about5 percent , compare

d t o les s tha

n 1 percentfo

r on e to n o r les s (AP

I 1990) . Vapo r clou d explosion s hav e occune d atquantities as lo w as 2 0 kg , butth e damag e the y have produce

d ha s bee n ver

y localize d an

d o f littl e concer

n regardin

g injurie s an

d losses . Significan

tblas teffect

s under semi-confine d condition s hav e occune d fo

r quantitie s a

s lo w as 100 k

g (22 0 pounds) . Release s as grea tas 1,00 0 metri c ton s hav

e bee n identified , bu

tthe y hav e usuall y produce d fires o r firestorms. Th e rat e o f discharge ha

s a large influence o n ai r mixing. Rate s o f discharg e lowe r tha

n about0.25 metri c ton s o f fue l pe r minut e d o no tsee

m t o b e a severe aeria

l explosio n risk (Lewi s 1980) , probabl y becaus e inadequat

e mixin g keep s th e air/chemica

l concentratio n belo w require d explosiv e limits . I n addition , th e presence o f object s i n th e cloud' s pat

h appear s t o affec tth e likelihoo d o f

explosion . Wiekem a (1984 ) conclude s that , "...whe n n o sizabl e object

s wer e i n th e clou d n o explosion s hav e bee n recorded , an

d tha ti n fact

, th e presenc e o f

obstacle s an

d confinementi s a necessar y conditio n for a

n explosio n t o occur. " H e als o note s that , "...a n ignitio n withi n abouton e minut e afte r th e beginnin g o f

th e releas e wil l enhance th e possibilit y o f a n explosion. " Ove

r 60 % o f th e vapor clouds studie d ignite d withi n 100 meter s o f th e releas e site . A stud

y b y Prug h (1987 ) conclude s tha

tth e occunenc e o f

a vapo r clou d explosio n rathe

r tha n a vapo r clou d fir

e (bot h o f whic h occu r under similar circumstances ) depend s upo n th e locatio n o

f th e ignitio n sourc e an

d th e amoun

to f turbulence o r mixin

g i n th e cloud . Fo r a

n unconfined vapor clou d explosio n t o occur , "turbulen tmixin g o f vapo r an d air, ignitio n o f

th e clou d ata poin tremot

e from th e source , an

d (probably) a minimu

m amoun to f vapo r atconcentration s withi n th e flammable rang

e (Klet z 1977 ; Lee s 1980 ) ar

e required. " Skark

a (1987 ) conclude s tha

tonl y th e centra

l zon e o f th e clou d o f

vapor s mixe d wit h ai r insid e th e explosio n limits can caus e an d contribut

e t o th e explosion . Man y flammable gase s hav

e relatively hig

h theoretica

l TN T equivalent

s compare d t o commerdal explosives , wher

e th e TN T equivalenti s th e relative weigh to f trinitrotoluen e (TNT ) tha tproduces th e sam e effec

tas i s produce

d ata give n distance b

y th e materia

l under consideration . Commerda l explosive s generall y hav e TN T equivalent

s betwee n roughl

y 0. 3 an d 2 . Th e theoretica

l TN T equivalentfor flammable gase s indicates th e explosiv e potential , assumin g th e materia

l explode s completely , calculated value s reporte d b

y Prug h (1987 ) rang

e from 4. 5 (fo r viny

l chloride ) t o 3 4 (fo r hydrogen) . Fo r mos thydrocarbons , th e theoretica

l TN T equivalen

ti s about1 2 (Prug

h 1987) . However , i n vapor cloud explosions , i tappear s thatonly a fractio

n o f th e vapo r i n th e clou d explodes . (I n contrast, for commerda l explosives , mos to f th e explosive materia

l presenti s expected t o b e involved i n th e explosion. ) For example , Prug h (1987 )

%*P.1 6

-9 - report s tha tfor vapo r clou d explosion s o f hydrocarbons , th e observed TN T equivalentwa s 1.0 , compare

d t o th e theoretica

l TN T equivalento f

12 . Fo r modellin g th e consequence s o f vapo r clou d explosions , a "yiel d factor " i s applie d t o accoun tfo r th e unexploded vapo r i n th e doud . Vapo r dou d explosion s ar e a rea l concer n t o communities neighboring industria l Chemica l facilities . Fo r example , i n 1973 , a massive vapo r clou d explosio n occune d i n Flixborough , England , followin g th e ruptur e o f a pip e carryin

g cyclohexan

e a t145° C an

d 120 psi . Fift

y t o 6 0 metri c ton s o f

cyclohexane wer e released . Th e explosio n destroyed th e chemica l plant, killin g 2 9 peopl e (mos to f them i n th e plantcontro l room) , an d damage d buildings 1/

2 t o 3/ 4 mile s away

, window breakag

e wa s reported up t o eigh tmile s fro m th e plan t(Eisenberg e ta

L 1975) . 6.1. 2 Vapor Qou d Fire s Vapo r clou d fires are simila r t o vapo r clou d explosion s excep textreme overpressures ar e no tgenerated . Instead , th e hazar

d associate d wit

h the m i s a rapidl

y moving flam

e frontI f a vapo r dou d o r plum e contact s a n ignitio n sourc e a

ta poin tatwhic

h its concentratio n i s withi n th e rang e o f it s upper an

d lowe r flammable limits , a wall o f flam e ma y flash bac

k toward s th e sourc e o f

th e ga s o r vapor (HCHA P 1989) . Thes e vapo r clou d fires are als o refene d t o a s flash fires. Followin g ignitio n o f a n over-ric

h clou d o f

fuel , a diffusion-typ e flame roll s bac k acros s th e dou d o f

fue l a s ai r i s mixe d furthe r wit h th e over-ric

h clou d unti l al l th e clou d i s burne d (Lewi s 1980) . Individuals engulfed i n such a vapo r clou d tha tthe n ignite s have a hig

h probabilit

y o f bein g killed . However , there were n o reported fatalitie s beyon d th e actua

l vapo r clou d du e t o radiation effect s i n a sampl e o f

vapo r cloud fires examine d b y Wiekem a (1984) . H e conclude s tha

tsinc e th e are

a outsid e o f

th e clou d exposed t o intens e therma l radiation i s small , n o fatalitie s du e t o therma

l radiation ca

n b e expeae d outsid e th e are a engulfed i n flame. Th e siz e o f th e vapo r clou d i s determined b y th e extentt o whic

h th e released materia

l disperse s i n th e atmospher e before ignition . 6.1 3 BLEVE s an d Fireball s Boilin g Liquid Expandin

g Vapo r Explosion s (BLEVEs ) occur when seale d tank s o f liqui d o r gaseou s hazardou s material s are expose d t o fire whic h ma y caus e excessive pressures withi n th e tan k combine d wit

h weakenin g o f

tan k walls . Th e sudde

n failur e o f th e vessel an

d rapi d vaporizatio n an

d expansio n o f

its contents i s terme

d a BLEVE . BLEVE s als o generall y resulti n ignitio n o f

th e vapor clou d when th e substance i s flammable, an d a larg e rising firebal

l ma y form, th e siz e o f

whic h wil l var y wit h th e acdden t condition s an

d th e typ e an

d amoun to f hazardou s materia l present. Although th e fireball i s generall y o f shor tduration , th e intens e therma l radiation generated ca

n caus e severe an

d possibly fata

l burn s t o expose d peopl e over relativel y considerabl e distances i n a matte r o f second s (HCHA P 1989) . Overpressure

s an d containe r fragmentprojectile s als o ma y b e generated b

y BLEVE s bu

tar e o f les s concern tha

n th e therma

l radiation (Nazari o 1988) . For al l majo r fue l releas e inddents studie d whic h le d t o BLEVEs , th e indden twa s accompanied b

y a majo r fir e indden t(Lewi s 1980) . Lewi s (1980 ) describes BLEVE s fo r fuel s as follows : Whe n a pressur

e vessel containin g a liquefied flammable gas o r a flammable liqui d i s heate d b y a n externa l fire whic h heat s th e meta

l wal l a tth e vapor space level , th e vesse l wil l ruptur

e into a numbe

r o f larg e piece s whic

h will rocke

tconsiderabl e distances as fue l insid e th e piece s burns . This i s accompanie d b y a larg e fireball an

d som e explosiv e pressur e effect s produce d from th e liquid rapidl

y expandin

g durin g th e propagation o f fracture s as th e vesse l ruptures . Thes e pressur e effect s ar e usuall y mino r compare

d wit h th e fire s starte d b y hea tradiation . Th e Center fo

r Chemica

l Proces s Safet

y Guideline s fo

r Chemica

l Proces s Quantitative Ris k Analysi s (CCP S 1989 ) describ e a firebal l a s follows :

^P.1 7

-10 - Fireball : Th e atmospheri c burnin g o f a fuel-ai r clou d i n whic

h th e energ

y i s mostly emitte d i n th e form o f

radian thea tTh e inne r cor e o f th e fue l releas e consist

s o f almos t pur e fuel whereas th e oute r laye r i n whic h ignitio n firstoccur

s i s a flammable fuel-ai r mixture . A s buoyanc

y forces o f

th e ho tgase s begi n t o dominate , th e burnin g clou d rise s an d become s mor e spherica l i n shape . Severa l spectacular acddent s have bee n classifie d as BLEVEs . On e o f th e mos tnotabl e wa

s ata Mexico Qt y liquefie d petroleum gas (LPG ) sit e where BLEVE s occurre d involving million s o f

pound s o f flammable gas an

d numerous tanks . Hundred s o f resident s i n home s adjacen

tt o th e plantwer e killed . A recentarticl e i n "Chemica l Engineering " suggest

s a guidelin e tha

tif 10 % o f a chemica

l vaporize s when i t i s release d t o th e atmosphere from a vessel , th e chemica l has a hig

h potential t o BLEV E (Nazari o 1988) . Pentan e an

d lighte r hydrocarbon

s generall y satisf y thi s vaporizatio n criterio n when containe d i n vessel s at thei r typical storag e temperatures an d pressure

s an d released t o th e atmosphere . Results produced b y th e model s for chemical s heavie r tha n pentan e hav

e therefor e no tbee n considered furthe r i n thi s assessment ; however , i tshoul d b e note d tha ti ti s no timpossibl e fo

r les s volatil e chemicals , when subjected t o elevate d temperatur

e an d pressur e conditions , t o resul ti n BLEVEs . 6.1. 4 Poo l Fire s A liqui d poo l fire i s a fire involving a quantit y o f liqui d fue

l spille d o n th e surfac

e o f th e land o r water . A n ignitio n sourc e mus tstar tth e poo l fire. Primar

y hazard s o f liqui d poo l fires are t o peopl e an d propert y involvin g exposure t o therma l radiation and/or toxi c o r conosiv e product s o f combustio n (HCHA P 1989) . 6.1. 5 Je tFire s Transportation an

d storage tank

s o r pipeline s containin g compresse d o r liquefied gases ma

y discharge gase s ata hig

h spee d if someho w puncture

d o r broke

n durin g a n acdden tTh e ga

s dischargin

g o r ventin g from th e hol e wil l for

m a ga s je ttha t"blows " into th e atmospher e i n th e directio n th e hol e i s facing , al l th e whil e entrainin g an

d mixin g wit h air . Whe

n th e ga s i s flammable an

d i tencounter

s a n ignitio n source , a flam e je to f considerabl e lengt

h ma y form. Fo r chemical s tha tar e liqui d unde

r ambien tconditions , n o ga s je twil l form ; liqui d o r vapo r migh tlea k ou tthroug

h a punctur

e o r break, bu

twil l no tblo w out . j 6. 2 Chemicals , Quantities , an d Conditions Use d i n Modellin g A variet y o f chemical s wer e modelle d for selecte d quantities . Th e chemicals , quantities , an d assumption s mad e regardin g typ e o f release , temperatur

e an d pressur e prior t o release , an

d meteorologica

l conditions , ar e discussed below .

6.2. 1 Chemical s an

d Quantitie s Chosen for Modellin g Te n commo n hydrocarbons , including alkanes , alkenes , an d aromatics , o f

widel y vaiyin g volatilit

y (boilin g point s from -103° C t o 137°C) an d flammability (a s indicate d b y flash point ) were chose n fo r consequenc e modellin g as representative example s o f a rang e o f flammable chemical

s tha tma y b e foun d i n commerce i n hig h volumes . Volatilit

y an d flammability ar

e importan

tcharacteristic

s i n determining acdden t consequences . Th e selerte d chemical s included ethylene , propane , propylene , n-butane , pentane , hexane , heptane , toluene , p-xylene , an d gasoline . Physical/chemica l properties o f

thes e chemical s ar

e liste d i n ExhibitE-2 , Appendi

x E . Ethylene , propane , propylene , an d n-butan e ar e gase s unde

r ambien tconditions ; th e othe r chemical s ar

e liquids . WHAZA N modellin g wa s carrie d ou tfo r release s o f

1,000 , 2,500 , 5,000 , 7,500,10,000 , 25,000 , 50,000,100,00 0 an d 180,000 pound s o f

eac h o f th e te n hydrocarbon

s t o gai n insigh t int o th e impac

to f th e siz e o f

a n acddental releas e o n potentia l consequences . Results o f modellin g ar

e presente d i n Sectio n 8 .



# ?? >

### -11

-

Modellin g o f 100,00 0 pound release s o

f eac h o f th e te n hydrocarbon s wa

s carrie d ou t

usin g th e other method s discusse

d i n Section 5 t o compar

e th e result s fromothe r

model s (PC-base

d calculatio n method s an d others ) wit

h WHAZAN

. Th e method s fo r al l th e model s use

d are discusse

d in Appendi

x B

. Result s o f modellin g b y al l method s wer

e foun d t o b e i n reasonabl e agreemen t Eigh t othe r organi c chemicals , includin g ethylen e oxide , ethyl chloride , acetaldehyde , acetone , trichloroethylene , aceti c add , benzaldehyde , an d dimethy l sulfoxid e wer e als o modelle

d fo r 100,00 0 pound release s usin

g th e WHAZA

N mode l fo r compariso n wit h th e hydrocarbons

. Som

e o f thes e chemical s (e.g. , trichloroethylen e and dimethy l sulfoxide ) are no t considered ver

y flammable; the

y wer e included fo

r compariso n purposes . Result s o

f modellin g 100,00 0 pound release s o

f th e hydrocarbon s b

y al l method s an

d WHAZA

N result s fo

r th e additiona l chemical s are presente d in Exhibi t D-1 , Appendi

x D

. 622 Instantaneou s an

d Prolonge d Release s Instantaneou s release s are thos e tha t tak e plac e ove

r aperio d o f tim e rangin g fromafe

w second s t o severa l minute s an

d the n essentiall

y stop
. The result

o f suc h areleas e typicall

y i s aliquid pool , apuf

f o f vapo r o r gas , o r distinc t cloud , bu t ca n als o involv

e a n explosion

. A sudde

n catastrophi c vesse

l failur e o r th e failur e o f alarg e piping connection ca n b e considered example s o

f instantaneou s releases

. Instantaneou s release s wer

e considere

d likel y t o have potentially mor

e sever e consequence s tha

n prolonge d release s (see below ) an

d wer e assume d as th e typ e o

f releas e in th e comparative modellin g usin g al l methods

. Prolonged o r

continuou s release s tak

e plac e ove

r longe r period s o f tim e and , whe n atmospheri c dispersion i s involved , typically produc e plume s stretche d ou t ove r longe r distances

. Failur

e o f asmal l piping connection o r

o f apiping gaske

t are example s o

f potentia l prolonged releases

. Fo r

modellin g purposes , prolonged release s wer

e assume d t o emanat

e from1. 5 inc h diamete r hole s i n containmen

t vessels

. Thi s simulate s th e shearin

g of f o f asmal l instrumen

t connection o n avesse

l or agaske t lea k in alarge r piec e o f piping

. Prolonged release s wer e modelle d usin g WHAZA

N fo r compariso n wit h instantaneou s releases ; th e consequence s are , i

n general , smaller

. 6.2 3 Initial Condition s Prio r to Releas e Flammabl e chemical s ar e handled and/o r store d at awid e variet y o f temperature s and pressure s at industria l facilities

. Condition s ca

n range fro mextremel

y sever e processin g condition s (hig

h temperatur

e an d pressure ) t o relativel

y lo w severit y storag e conditions

. Ver

y volatil e chemical s ma

y b e store d a s liquid s unde r pressur e and/o r a t lo w temperatures
. Les s volatil e chemical s ca n b e store d a

t ambien t temperature s an d pressures . Acddent

consequenc e modellin

g i s dependen

t o n initia l releas e conditions

. Becaus e i t i s no t uncommo n fo r storag e vessel s t o b e site d close r t o plant fenceline s an

d henc e neighborin

g communitie s tha

n processin

g equipmen t

an d becaus e storag e vessel s generall y contain muc

h large r volume s o f materia l tha n processin

g equipment

storag e temperature s an

d pressure s that

ma y b e foun d i n industi y practic e wer

e assume d a s initia l releas e condition s fo

r modellin g purposes . Temperature s and pressure s use

d i n modellin g are listed b

y chemica l in Exhibi t E-1 , Appendi

x E

. 6.2. 4 Meteorolog

y Th e primar

y meteorologica

l condition s use

d fo r modellin g b y al l method s wer

e 3. 0 meter s pe

r secon d win d speed and D atmospheri c stability , representing average o r neutra l atmospheri c condition s rather tha n worst cas e situations

. Mor

e extrem e condition s (fo

r dispersion) o

f 1. 5 meter s pe

r secon d win d spee d an d F atmospheri c stabilit

y wer e als o use d fo r WHAZA N modellin

g to sho w th e effec t o f varyin g meteorologica

l condition s o n acddent

consequences . A s explaine d i n th e Green Boo

k (Technica l Guidanc e 1987) , thes e condition s correspon d t o stabl e air

an d lo w win d speed , condition s unde

r whic h dispersion result s fo

r distance s t o variou s hazar

d criteri alevel s are generall y large r tha n thos e calculated unde r condition s usuall

y considere

d typica l

%^P.1 9

-12 - 7. 0 Hazar

d Criteri a Th e exten tan

d severit y o f th e impact

s o f a n acdden tdepend s o n th e typ e o f consequence tha

tresults . Acddent s involvin g flammable substances ca n resul ti n therma l radiation from fires o r blas toverpressures from explosions , o r both . Th e consequence s for various types o f acddents hav

e bee n summarize

d below : Acdden tConsequenc e Unit s Vapo r Qou d Explosio n Overpressur e ps i BLEV E Therma l radiation kW/m 2 Poo l Fire Therma l radiation kW/m 2 Je tFir e Therma l radiation kW/m 2 Vapo r Qou d Fire Ignition o f fir e LFL where ps i = pound s pe r squar e inch , kW/m

2 = kilowatt

s per squar

e meter , an

d LFL = lowe r flammable limit ; thes e are discussed furthe r below . Fo r modellin g purpose s severa l hazar d criteri a level s o f

overpressure , therma

l radiation , o r concentratio n associate d wit

h each type o f

acdden tconsequence wer e use d for modelling . Th e effect s o f th e hazar d criteri a an

d th e distance s resultin g from modellin g ca n the n b e use d b

y EPA i n regulator

y determinations . Fo r a give

n acdden tth e WHAZA N mode l wa s use d t o calculat

e th e distance fro

m th e acdden tsit e t o th e chose n hazar

d criteria level . Th e hazar d criteria level s tha

twer e used i n modellin g ma

y hav e effect s tha t range from mino r injuiy t o human s throug h various level s o f

propert y damag e t o potentially lethal effect s o n human

s (se e Appendi

x C) . Thes e ar

e discusse d belo w b y typ e o f acdden t 7. 1 Hazar

d Criteri a for Vapor Qou d Explosions Th e consequenc e o f

greates tconcer

n fo r vapor cloud explosion s i s th e blas twave . Blas twave s from acddenta l explosion s ca

n caus e damag

e t o peopl e an

d propert y b y subjecting the

m t o transientcrushin

g pressures an

d winds . Relativel y simpl e concept s hav e bee n used t o conelat e blastwav e propertie s wit

h damage . Blas twave damag e i s primaril

y a function o f

eithe r th e pea

k overpressure , th e impulse , o r som e combinatio n o f

thes e factors . Pea

k overpressur

e i s mostcommonl

y used . Fo r modellin g vapo r clou d explosions , overpressures o f 0.3,0.5,1.0 , 3.0 , an

d 10. 0 ps i were considered . A ta n overpressur

e o f 0. 3 psi , 1 0 percento f

window glas s ma

y b e broken (Lee s 1980) . A n overpressur e level o f 0. 5 ps i ca

n caus e window s t o shatter , wit

h som e frame damage

s (Brasi e an

d Simpson 1968) . Overpressur e o f 1.0 ps i ca

n caus e partia

l demolitio n o f

house s an

d i s th e threshold fo

r skin laceratio n from flying glas s (Lee s 1980) . A n overpressur

e leve l o f 3. 0 ps i ca

n caus e stee l fram

e buildings t o becom e distorted an d pulle d awa

y from thei r foundations (Lee s 1980) ; thi s overpressur e ca n als o hur l a person t o th e groun

d (Brasi e an

d Simpso n 1968) . A n overpressur

e o f 1 0 ps i ma

y totall y destro

y buildings (Lee s 1980 ) an d i s th e threshol d for lun g hemonhag e (U.S . DO T 1988) . Appendi x C , Sectio n Ci.l , present s additiona

l information o n damag

e an d injui y caused b

y various overpressur

e level s from explosions . 7. 2 Hazar

d Criteri a for Vapor Clou d Fire s Th e minimu

m concentratio n o f

a vapo r o r ga

s i n air tha

twil l ignit

e an d propagat

e flame i s know

n as it s lowe r flammable limi t(LFL ) concentratio n o r lower explosive limi t(LEL ) concentration . Th e word s flammable an

d explosive ar

e used interchangeabl

y suc h tha tLP L value s equa

l LEL values ; th e concentratio n o f

a fue l tha twil l bur n i n ai r als o ca

n b e expeae d t o explod e unde r th e appropriat

e conditions . Similarly , th e maximu m concentratio n o

f a ga s o r vapor i n air tha

twil l ignit

e an d propagat

e flame i s know

n as th e upper flammable limi t(UFL ) o r upper explosiv e limi t(UEL ) o f th e fuel (HCHA P 1989) . Fo r vapo r clou d fires, dispersio n modellin g wa s carrie d ou tusing concentrations equa l t o 5 0 percento f

th e LFL , th e LFL , an

d twice th e LF L Level s belo w th e LF L ar e use d t o accoun

tfo r variabilit

y withi n th e 

# £ 5-13 -

dou d fro m it s edg e t o it s cente r an d inaccurade s i n dispersion modelling . Thi s i s base d o n guidanc

e i n th e WHAZA N manua

l (WHAZA N 1988 ) which recommend s th e following : Whe n calculatin g saf

e distance s from flammable releases , thes e difficultie s [uncertainties i n concentration ] indicat

e tha tth e analystshoul d consider concentration s somewha tbelo w th e LFL . A concentratio n o f LFL/ 2 o r LFL/ 4 i s normall

y used . 7 3 Hazar

d Criteri a fo r BLEVEs , Poo l Fires , an d Je tFire s Th e consequenc e o f

greates tconcer

n resultin g from BLEVEs , poo l fires , an d je tfires i s heatradiation . I n th e cas e o f

BLEVEs , injuries an

d fatalitie s mightals o resultfrom overpressures an d containe r fragment projectiles , buttherma

l radiation i s considere d t o b e th e consequence o f greates tconcer

n an d i s th e consequenc e addresse

d i n th e modelling . Huma n injur y o r fatalit

y fro m heatradiation from fires i s likel y t o occu r a s a resul to f

direc texposur e t o a fire rathe

r tha n as a resul to f

propert y damag e cause d b

y a fire. Th e exten to f

th e injur y caused b

y heatradiation depends bot h o n th e hea

tleve l an d th e tim e o f

exposure . Th e duratio n o f

th e fire an

d th e lengt

h o f tim e i tmigh

ttake a n expose d perso n t o escap e o r tak e shelte r from th e fire woul d b e importan tconsiderations . Th e WHAZA N model produces result s for duration o f

th e fire an

d distance from th e fire fo r thre e heat radiatio n level s for BLEVEs , poo l fires, an d je tfires. For BLEVE s an d je tfires, duration an

d distanc e result s are produce

d fo r hea tradiation level s o f

4.0,12.5 , an

d 37. 5 kW/mr According t o th e WHAZA N manual , a hea tradiation leve l o f 4. 0 kW/m

2 woul d lead t o a 1 percen tprobabilit

y o f fatalit y afte r a n exposure tim e o f

15 0 seconds . Fo r 12. 5 kW/m 2 th e probabilit

y o f fatalit y i s 1 percentafte

r a 3 0 secon d exposure an

d 5 0 percen

tafte r a n exposur e tim e o f 8 0 seconds . Fo r a hea

tradiation level o f

37. 5 kW/m

2 th e probabilit

y o f fatalit y i s 1 percentfo r a n 8-second exposure , 5 0 percentfor a 20-secon d exposure , an d 9 9 percentfo r a 50-secon d exposur e (WHAZA N 1988) . Fo r poo l fires, WHAZA N gives result s for 1.6 , 4.0 , an d 12. 5 kW/m

2
. A heatradiation leve l o f 1.6 kW/m

2 would lead t o a 1 percen tprobabilit

y o f fatalit y afte r 50 0 second s (WHAZA N 1988) . Appendi x C , Sectio n C3.1 , present s additiona

l infonnatio n o n therma l radiation . 8. 0 Modellin g Result s WHAZA N modellin g wa s carrie d ou tfo r vapo r clou d explosions , vapor clou d fires, BLEVES , poo l fires, an d je tfires o f

th e hydrocarbon

s usin g th e assumptions discusse d above . WHAZA N result s are presente d i n th e followin g section s b y consequenc e type . Resultin g distances fo r selecte d quantities an

d severa l hazar d criteri a level s ar

e provided ; thes e result

s hav e bee n considered i n makin g regulator

y decision s regardin g flammable chemicals . Th e input s use d fo r th e WHAZA N model ar e presented i n detai l i n ExhibitE-3 , Appendi

x E . Results o f

modellin g b

y othe r methods an

d additiona

l WHAZA N result

s ar e presente d i n ExhibitD-1 , Appendi x D . A s note d earlier , result s from al l th e method s ar e i n reasonabl e agreemen t 8. 1 Vapo r Clou

d Explosio n Result s Exhibit2 present

s WHAZA N modellin g result s fo r vapor clou d explosion s o f fou r hydrocarbo

n gase s for quantitie s o f

1,00 0 t o 180,000 pounds . Ethylen e an d propan e ar e assume d t o b e liquefied b

y refrigeration ; propylen e an

d n-butane are assume

d t o b e liquefied unde

r pressure . Vapo r clou d explosio n results coul d no tb e obtaine d for liquid s unde r ambien tconditions . Th e exhibi

tshow s th e fraction flashed, obtaine d from th e linke d models , an d th e quantit

y assume d t o b e i n th e cloud , calculated from th e tota l quantit y release d an

d th e fraction flashed. Thi s quantit y wa s use d i n th e vapor clou d explosio n stand-alon e model . Distance s calculate d fo

r severa l overpressur

e level s ar

e presented . Although th e modelling shows distance s o f approximatel

y 10 0 meter

s for releas e quantitie s a

s smal l a s abou t5,00 0 pound s a

toverpressure

s o f 1.0 ps i an d lower , th e probabilit

y o f a vapo r clou d explosio n occurrin g i s relativel

y lo w fo r vapor cloud s containin g quantitie s smaller tha n 10,00 0 pound s (AP

I 1990 , Prug

h 1987) , as note d earlier . Not e als o that th e quantit

y i n th e clou d i s considerabl y smaller tha

n th e quantit

y released ; i.e. , a releas e o f 10,000 pound s o f flammabl

e materia l woul d probabl

y resulti n a cloud containing muc h les s tha n 10,00 0 pound s (Exhibit 

# S oP.2 1

-14 - Exhibit2 DISTANCES FO

R VAPO R CLOU D EXPLOSIONS OF FOU R UQUEFIE D GASE

S FO R INSTANTANEOU

S RELEASE

S O F LOO O TO 180,00 0 POUND S DETERMINE

D USING FRACTIO

N FLASHED , WHAZA

N STAND-ALON

E MODE L Distanc e i n Meter

s t o Variou s Overpressure s

Chemica l (Initia l Conditions )

Ethylen e (liquefie d b

y refrigeratio n 17 5 K , 1. 3 Bars )

Propylen e (liquefie d unde r pressur e 29 3 K , 13. 3 Bars )

Propan e (liquefie d b

y refrigeratio n 23 2 K , 1. 3 Bars )

n-Butan e (liquefie d unde r pressur e 29 3 K , 6. 3 Bars ) Quantit y Quantit y Release d Fractio n i n Cloud (lbs ) Flashe d (lbs )

1,00 0 0.02 3 2 3 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 5 8 11 5 173 23 0 575 1,15 0 2,30 0 4,14 0 1,00 0 0.32 9 32 9 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 82 3 1,64 5 2,46 8 3,29 0 8,22 5 16,45 0 32,90 0 59,22 0 1,00 0 0.01 5 1 5 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 3 8 7 5 11 3 15 0 37 5 75 0 1,50 0 2,70 0
11 3 11 3

28 3 56 5 84 8 1,13 0 2,82 5 5,65 0 11,30 0 20,34 0 0. 3 ps i

(m )

15 1 205 25 9 29 6 32 6 44 3 55 8 70 3 855 37 2 49 4 62 2 712 80 1 1,09 0 1,37 0 1,73 0 2,10 0 130 17 7 223 25 5 28 0 38 1 47 9 60 4 735 275 345 43 4 49 7 54 6 71 3 93 6 1,18 0 1,43 0 0. 5 ps i

(tn )

9 8 13 4 168 19 3 21 2 28 8 36 2 45 7 55 6 242 32 1 40 4 46 3 52 1 706 89 0 1,12 1 1,36 4 8 5 11 5 14 5 16 6 18 2 24 7 312 39 3 47 8 179 224 28 2 32 3 35 5 46 3 60 7 766 933 1. 0 ps i

(m )

5 7 7 7 9 7 11 1 12 2 16 6 20 9 26 3 32 1 139 18 5 23 3 26 7 30 0 40 8 51 3 64 7 78 7 4 9 6 6 8 3 9 6 10 5 14 3 180 22 7 27 6 10 3 12 9 16 3 18 6 20 5 26 7 35 0 44 2 53 8 3. 0 ps i

(tn )

2 3 3 1 3 9 4 4 4 9 6 6 8 4 10 5 12 8 5 6 7 4 9 3 10 7 120 16 3 20 6 25 9 315 2 0 2 6 3 3 3 8 4 2 5 7 7 2 9 1 11 0
4 1 • 5 2 6 5 7 5 8 2 10 7 14 0 17 7 21 5 10. 0 ps i (m )

1 1 1 5 1 9 2 2 2 4 3 3 4 2 5 3 6 4 2 8 3 7 4 7 5 3 6 0 8 2 10 3 12 9 15 7 1 0 1 3 1 7 1 9 2 1 2 9 3 6 4 5 55 2 1 2 6 3 3 3 7 4 1 5 3 7 0 8 8 10 8



# g nP.2 2

-15 - 2 show s 15 0 t o 330 0 pound s i n th e clou d fo r a releas e o f

10,000 pounds) . Distance s fo r ethylen e an

d propane , assumed t o b e liquefie d b y refrigeration , are considerabl y shorte r than fo r propylen e an d n butane , assumed t o b e liquefie d unde r pressure , probabl

y becaus e a treduced temperature s les s o f th e ethylen e an d propan e are i n th e vapo r phas e t o contribut e t o th e amountflashed upo n release . Fo r propylen e an

d n-butane , modellin g result s indicat e distances greater tha

n 10 0 meter

s for a n overpressur

e o f 1.0 ps i fo r al l th e quantitie s modelled . Fo r a n overpressur

e o f 1. 0 psi , distance s fo r propan e range from 4 9 meter s for a 1,00

0 pound releas e t o 27 6 meter s fo r a 180,000 pound release , whil e fo r propylene th e distance s ar e fro

m 13 9 meters for 1,000 pound s t o 78 7 meter s fo r 180,00 0 pounds . Th e WHAZA N calculate d distance s ar e base d o n "limi tvalues " t o charaderisti c damag e level s an d th e scalin g la w o f distances , whic

h state s tha

tdistanc e i s proportiona

l t o th e cub e roo to f

quantit y o f explosiv e materia L Fo r TNT , empirica

l graph s o f scale d distanc

e versus overpressur

e hav e bee n derived . I

twa s assumed , base d o n th e scalin g law , thatth e WHAZA N limi tvalue s woul d b e proportiona l t o th e scale d distanc e value s for TNT . Th e limi tvalue s wer e related t o a grap

h o f pea k overpressur

e versu s scale d distanc e fo r TN T from Lee s (1980) , th e source dte d i n th e WHAZA N manual ; using thi s relationshi p an d th e description s o f

th e damag

e level s i n th e WHAZA N manual , th e Yello w Book , an d Lees , th e overpressur

e relate d t o eac

h limi tvalu e wa

s estimated . Fo r a

n overpressur

e o f 0. 5 psi , n o limi tvalu e was provided ; therefore , a limi tvalu e wa s estimated fro

m th e grap

h o f overpressur

e an d scaled distanc e an

d its relationshi p t o th e limi tvalues . Th e value s for 0. 5 ps i i n Exhibit2 are base d o n thi s estimate d limi tvalue . T o obtai n th e WHAZA N modellin g result s presented here , th e linke d model s were used t o determin e th e fractio n o f

liqui d instantl

y flashe d t o vapor, whic

h th e mode

l gives onl y fo

r gases . Th e fraction flashed wa s use d t o estimate th e flammable mas s i n th e cloud ; thi s quantit y wa s use d t o ru

n th e stand-alon e mode l fo r vapo r clou d explosion , rathe r tha n th e linked models . Th e linked model s wer e no tuse d fo r vapo r clou d explosion s becaus e i twa

s foun d tha tthes e model s di

d no tproduc

e reasonabl e result

s fo r thi s typ e o f consequence ; Le. , th e quantit y apparentl

y assume d t o b e i n th e clou d seeme d unreasonabl y hig h (muc h highe r than th e quantit

y tha twoul d b e immediatel

y flashe d into vapor) . Exhibit2 show

s result s fo r ethylen e an

d propan e unde r low-temperatur

e storage conditions . Ethylen e an d propan e wer e als o modelle d assumin g initia l releas e condition s o f

higher temperature

s an d pressures , similar t o th e condition s assume d fo r propylene an

d n-butane ; unde

r thes e conditions , distance s were similar t o thos e foun

d fo r propylen e an

d n-butane , indicating tha tgase s liquefied b

y refrigeration ma

y pos e les s potentia l ris

k o f vapor clou d explosio n tha n gases liquefied unde

r pressure . Exhibit3 show

s WHAZA N modellin g result s a s a grap h o f quantit y release d versu

s distance fo

r vapo r clou d explosions , base

d o n 1. 0 ps i overpressure . I

ti s assume

d tha tgraph s o f quantit y versu s distanc e for othe r overpressur

e level s woul d sho w simila r increases i n distanc

e wit h increasing quantit

y released . Quantitie s release d displaye d o n th e grap

h rang e from 1,00

0 t o 50,00 0 pounds . Th e curve s shown i n Exhibit3 illustrat

e th e fac ttha tdistance i s proportiona

l t o th e cub e roo to f

th e quantit

y o f explosive , accordin g t o th e scalin g la w o f distances , whic

h i s th e basi s for WHAZA N modellin g o f vapo r clou d explosions . Thus , a

ta specifi c hazar

d criteria level , th e smaller th e quantit y released , th e muc

h smalle r th e distanc e for experiencing th e impaa . ExhibitC-6 , i n Sectio n C1. 2 o f Appendi x C , show s WHAZA N modellin g result s fo r release s o f

100,00 0 pound s o f ethylen e an

d propylene . Distance s t o differen toverpressur

e level s ar

e displaye d graphically . Thes e result

s indicat e tha tth e choic e o f

overpressur

e level ha s a significan

teffe a o n determining th e affeae d distance , particularl y a tlo w overpressures . Fo r example , for propylene th e affeae d distanc e decrease s from 1,12 1 meter s t o 64 7 meter

s i f a n overpressur

e o f 1. 0 ps i i s used rathe

r tha n 0. 5 psi . Simila

r decrease s occu r for th e othe r chemicals . Th e grap h o f distanc e versus overpressur

e become s relatively flat betwee n overpressure

s o f 3. 0 an d 10.0 . WHAZA N modellin g wa s als o carrie

d ou tusin

g meteorologica

l condition s o f

1. 5 meter s pe r secon d win

d spee d an d F atmospheri c stability . Thi s wa s don e t o show th e impact s o f varyin g meteorological condition s o n acciden

tconsequences . Result

s fo r vapo r cloud explosion s wer

e identica l t o thos e obtaine d usin g 3. 0 meter

s per secon d win

d spee d an

d D atmospheric stability , indicating tha tth e vapo r clou d 

# <3f c

## 60 0

50 0

40 0 OT

_ _ O 

## o ^ 30 0 o c ( 0



## ° 20 0

10 0 - * - Exhibi t3 QUANTIT

Y RELEASE

D VERSU

S DISTANC

E FOR VAPO

R CLOU D EXPLOSIONS , INSTANTANEOU S RELEASE

S WHAZA N Modellin g fo r 1,000-50,000 pounds , 1. 0 ps i Overpressur e 

## Ethylene 4 1 

## Propylene* * Propan e * n-Butan e * *

1 0 2 0 3 0 4 0

Quantit y Release d (thousand s o f pounds ) 5 0

* Liquifie d b y refrigeratio n
* * Liquefie d unde r pressur eP.2 4

-17 - explosio n result

s usin g WHAZA N ar

e no tdependento n meteorological assumption s made . Thes e result s are presented i n ExhibitD-1 , Appendi x D . WHAZA N modellin g for a prolonge d releas e wa s als o undertake

n t o compar

e th e result

s o f assuming a

n instantaneou s versus a prolonge d release . However , thi s attempt , whic h use d moderat

e meteorological conditions , produce

d n o vapo r clou d explosio n results . I twa s no tpossibl e t o determin e wh y th e model produce d n o vapo r dou d explosio n dat a for prolonge d releases . ARCHI E modellin g wa s the n trie d for modellin g prolonge d release s (assuming a 1.5-inc h hole ) o f 1,000 t o 10,00 0 pound s o f propylene . I n th e cas e o f a liqui d release , th e result s fo r bot h instantaneou s an

d prolonge d release s were essentiall y identical ; therefore , thes e result

s are no tpresente d here . I f a prolonge d ga s releas e was assumed , th e mode l calculated th e same distances fo r eac h differen tquantit y released . Release s o f

othe r gases woul d probabl y provid e similar results . Thes e result s ar e no tlogicall y consisten tan d th e particula

r reason(s ) fo r th e inconsistende s ar

e no tknown . However , thi s ma y b e a functio n o f

th e limitation s o f

th e ARCHI E model atsmall releas e quantities . S2 Vapor Qou d Fire Result s Exhibit4 display

s th e result

s o f dispersio n modellin g usin g WHAZA N for vapo r cloud s o f flammable liquid s an d gases . Th e dat

a presente d includ e th e downwin d an d crosswin

d distance s atwhic

h th e concentratio n i n th e cloud i s equa l t o 5 0 percen

to f th e LFL , th e LFL , an

d twice th e LFL . Th e downwin d distance i s th e maximu

m distance a twhic

h th e specifie d concentratio n i s reached ; th e crosswin d distanc e i s th e widt h o f th e clou d o f

flammable vapo r a

ttha tpoin tTh e modelle d aosswin d distances are muc h smalle r tha

n th e downwin

d distances , roughl

y 6 percent , for th e chemical s an d condition s analyzed . Fo r a given downwin

d distance , th e total are

a (as a functio n o f

downwin d an d aosswin d distance ) potentiall y affeae d b y a vapor clou d fir

e i s likel y t o b e muc

h smaller tha

n th e are a tha tmigh tb e affede d b

y a vapo r clou d explosion ; for a fatalit y t o result , a perso n woul d hav e t o b e locate d withi n th e limite d area covered b y th e vapor cloud an

d engulfed i n th e ensuin g fire . Th e largestmodelle d downwin d distance result

s (approximatel

y 1,80 0 meters ) were for a releas e o f 180,000 pound s o f ethylene ; a 1,00

0 pound releas e o f

p-xylene showed th e smalles tdownwin d distance (abou t2 0 meters ) results . Ethylene als o provide d th e larges tdownwin

d distance an

d p-xylene th e smalles tatth e othe r hazar

d criteria level s analyze

d for vapo r clou d fires. Vapo r clou d fires were modelle d usin g WHAZA N b y runnin g th e linke d WHAZA N model s t o obtai n th e poo l evaporation rate, whic h i s als o show

n i n Exhibit4 . Th e poo l evaporatio n rat e wa s use d as th e releas e rate fo r th e stand-alon e buoyan

tplum e dispersio n model . Not e tha tth e fraction flashed canno tb e use d wit h th e buoyan

tplume dispersio n model ; therefore , th e result s show n here d o no tinclud e th e quantit y o f gas immediatel

y flashed into vapor o n release , butonl y th e quantit y tha tevaporates from a pool . Fo r propylene an

d n-butane , gases assume

d t o b e liquefie d unde

r pressure , th e fraction flashed i s appredabl e (3 3 percen

tfo r propylene , 1 1 percen

tfor n-butane) , indicating th e calculate d distance s fo r thes e material s ma y b e understated . Exhibit5 present

s WHAZA N vapo r clou d fir e result s a s a grap

h o f quantit y release d versu s distanc e for instantaneou s releases , assumin g moderat

e meteorologica

l condition s an

d modellin g t o a concentratio n equa l t o 5 0 percen

to f th e LFL . Distance s ar

e clearl y no tlinearly relate d t o th e quantit y released ; Le. , inaeasin g th e quantit

y released b

y a faao r o f

te n increases th e distance b y a faao r o f

approximatel

y two an d one-half fo r th e chemicals modelled . ExhibitC-7, i n Sectio n C 2 o f Appendi x C i s a graphica

l presentatio n o f

result s base d o n 5 0 percento f

th e LFL , th e LFL , an

d twic e th e LFL fo

r vapor clou d fire

s fo r two hydrocarbons . Thi s analysis wa s don e t o determine th e sensitivit

y o f th e model result

s t o changes i n th e flammable limi tlevel . Usin g th e LFL rathe r tha n 5 0 percen

to f th e LFL for 100,00 0 pound s o f ethylen e lower

s th e affeae d distance , a s woul d b e expeaed , bu

tb y muc h les s tha n a faao r o f

two . Th e effe a o f

changing from th e LFL t o twic e th e LF L i s eve n smaller . Th e dat

a presente d i n Exhibit4 sho w there i s littl e differenc e i n distance base d o n varyin g th e hazar d criteria level s fo

r th e othe r chemical s analyzed . 

# q oExhibit4 DISTANCE S FO

R VAPO R CLOU D FIRE S FRO

M EVAPORATIN

G POOL S FRO M INSTANTANEOU

S RELEASES , MODERAT E METEOROLOGY*, DETERMINE

D USING WHAZA

N Distanc e i n Meters to Three Concentrations

1/ 2 LF L LF L 2 LF L
Chemica l (Initia l Conditions ) Ethylen e (liquefie d b

y refrigeratio n 17 5 K , 1. 3 Bars )

Propylen e (liquefie d unde r pressur e 29 3 K , 13. 3 Bars *

Propan e (liquefie d b

y refrigeratio n 23 2 K , 1. 3 Bars ) Quantit y

Release d (lbs ) 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 i 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Evaporatio n

Rat e (Ib/s ) 6 0 11 5 19 0 254 31 3 61 1 1,01 2 1,67 8 2,58 0 2 0 4 2 6 8 9 0 11 0 21 4 35 3 58 7 90 0 2 4 4 9 7 9 10 8 132 26 0 43 0 71 2 1,09 1 Downwind

Distanc e (m ) 20 3 29 4 39 1 46 2 52 2 76 8 1,03 0 1,39 0 1,81 0 10 6 15 8 20 7 24 2 27 0 39 4 52 7 705 90 5 11 2 16 2 214 25 4 28 5 41 7 55 7 74 7 95 9 Crosswind

Distanc e (m ) 1 3 18 2 4 2 8 3 1 45 5 8 7 7 9 7 7 1 0 1 3 1 5 1 7 2 4 3 1 4 1 5 2 7 1 0 1 3 1 6 1 8 2 5 3 3 4 3 5 4 Downwin d Distanc e (n ) 13 8 199 26 4 31 1 35 1 51 4 68 8 925 1.19 0 7 4 10 7 14 1 164 18 4 26 6 35 4 47 3 60 5 TT 11 0 14 5 17 2 19 3 28 2 37 5 50 0 64 0 Crosswind

Distanc e (m ) 9 1 3 1 6 1 9 2 1 3 1 4 0 5 3 6 7 5 7 9 1 0 1 2 1 7 2 2 2 8 3 6 5 7 9 1 1 1 2 1 7 2 3 3 0 3 8 Downwin d

Distanc e (m ) 9 5 13 5 17 9 21 1 23 7 34 6 46 2 61 8 79 3 6 0 8 7 11 2 13 1 14 7 21 2 28 1 37 5 47 9 5 5 7 7 9 9 11 7 13 1 19 1 253 33 7 43 0 Crosswin d

Distanc e (m ) 6 9 1 1 1 3 1 5 2 1 2 8 3 6 4 6 4 6 7 9 9 13 1 7 2 3 2 9 4 5 7 8 9 1 2 16 2 1 2 6 

## 9

°



# j a * Win d spee d 3. 0 meter s pe r second , atmospheri c stabilit y clas s D .-



## X > 9X> Chemica l (Initia l Conditions ) n-Butan e (liquefie d unde r pressur e 29 3 K , 6. 3 Bars )

Pentan e (29 3 K, 2.7 4 Bars )

Gasolin e (29 3 K , 1.01 3 Bars )

- Quantit y

Released (lbs ) 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25.00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0

* Win d spee d 3. 0 meter

s pe r Exhibi t 4 DISTANCE S FO R VAPO R CLOU D FIRE S FRO M EVAPORATIN G POOL S FRO M INSTANTANEOU S RELEASES , MODERAT E METEOROLOGY" ,

Evaporatio n Rate (Ib/s ) 1 1 2 4 4 0 5 3 6 4 12 6 20 9 346 53 4 7 1 5 2 4 3 3 4 0 7 7 12 8 21 2 32 6 7 1 3 22 2 9 3 5 7 1 11 7 19 4 29 8

second , atmosphe

r DETERMINE D USIN G WHAZA N

(continued ]

1 Distanc e i n Meter s to Thre e Concentration s 1/ 2 LF L Downwin d Distanc e (m ) 7 3 10 3 13 5 159 17 8 25 9 34 5 46 0 58 8 5 3 8 1 10 1 12 0 13 3 19 3 25 6 34 1 435 5 5 78 10 0 11 5 13 2 19 1 25 4 33 8 43 1

i c stabilit y Crosswin d

Distanc e (m ) 5 7 9 1 0 1 1 1 6 2 1 2 8 3 5 4 5 7 8 9 1 2 1 6 2 1 26 4 5 7 8 9 1 2 1 6 2 1 26

clas s D . LF L Downwin d Distanc e (m ) 4 9 73 93 10 8 12 0 17 5 233 30 9 39 6 3 8 5 7 72 8 4 9 2 13 1 17 3 23 0 29 4 3 9 5 5 7 1 8 1 8 9 13 0 17 2 22 8 290 Crosswin d

Distanc e (m > 3 5 6 7 8 1 1 1 5 1 9 2 4 3 4 5 6 6 9 1 1 1 4 1 8 3 4 5 5 6 8 1 1 1 4 1 8 **

•

2 LF L Downwin d Distanc e

. (m ) 3 5 5 2 6 6 7 6 8 4 11 9 158 20 9 26 7 2 7 4 1 5 1 5 9 65 9 0 11 8 15 6 19 9 2 8 3 9 5 0 5 7 6 3 8 9 11 7 15 5 19 6 Crosswin d Distanc e (m ) 2 3 4 5 6 8 1 0 1 3 1 7 2
• • 3 3 4 4 . 6 8 1 0 1 3 2 3 3 4 4 6 8 1 0 1 2 -

-

-

i 

## £

•Exhibit4 DISTANCES FOR VAPO R CLOU D FIRE S FRO

M EVAPORATIN

G POOLS FRO M INSTANTANEOU

S RELEASES , MODERAT E METEOROLOGY*, DETERMINE

D USIN G WHAZA

N (continued ) Distanc e i n Meters to Three Concentration s

1/ 2 LF L LF L 2 LF L Chemica l (Initia l Conditions )

Hexan e (29 3 K , 1.01 3 Bars )

Heptan e (29 3 K , 1.01 3 Bars )

Toluen e (29 3 K , 1.01 3 Bars ) Quantit y

Release d (lbs ) 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Evaporatio n

Rat e (lb/s ) 4 9 1 3 18 2 2 4 4 7 3 12 1 18 5 2 4 i 9 1 1 1 3 2 6 4 2 7 1 10 8 2 4 7 9 9 2 0 3 3 5 3 8 2 Downwin d

Distanc e (m ) 4 1 5 8 7 1 8 2 9 1 133 17 6 23 3 29 7 2 9 4 1 5 8 6 5 7 1 9 9 13 0 17 3 21 9 3 1 4 3 5 3 6 1 6 4 8 9 11 7 15 4 19 6 Crosswind

Distanc e (m ) 3 4 5 5 6 9 1 1 1 5 1 8 2 3 4 4 5 7 9 1 1 1 4 2 3 4 4 4 6 8 1 0 1 2 Downwin d Distanc e (m ) 2 9 4 1 5 0 5 8 6 5 9 1 11 9 158 20 1 2 1 2 9 4 1 4 6 5 0 7 1 8 9 11 8 15 0 2 2 31 3 7 4 3 4 3 6 4 8 3 10 5 13 4 Crosswind Distanc e (m ) 2 3 3 4 4 6 8 1 0 1 3 1 2 3 3 3 5 6 8 1 0 1 2 2 3 3 4 6 7 9 Downwin d Distanc e (m ) 2 1 2 9 3 6 4 1 4 6 6 5 8 3 10 8 13 6 1 5 2 1 2 9 3 3 3 6 5 0 6 3 8 2 10 1 16 2 2 2 7 3 1 3 1 4 6 5 9 7 4 9 2 Crosswin d

Distanc e (m ) 1 2 2 3 3 4 6 7 9 1 1 2 2 2 3 4 5 7 1 1 2 2 2 3 4 5 6 

# s

L P Wi - n d spee d 3. 0 meter s pe r second , atmospheri c stabilit y clas s D .Exhibit4 DISTANCE S FO R VAPO R CLOU D FIRE S FRO

M EVAPORATIN

G POOL S FRO M INSTANTANEOU

S RELEASES , MODERAT E METEOROLOGY*, DETERMINE

D USING WHAZA

N (continued ) Distanc e i n Meters to Three Concentrations

1/ 2 LF L LF L 2 LF L Chemica l (Initia l Conditions ) p-Xylen e (29 3 K , 1.01 3 Bars ) Quantit y

Release d (lbs ) 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,000 - 100,00 0 180,00 0 Evaporatio n

Rat e (tb/s ) 1 2 4 4 7 1 1 2 0 3 1 4 9 Downwin d

0 1 stanc e (m ) 2 1 3 0 4 2 4 2 4 8 6 7 8 6 11 1 14 1 Crosswin d Distanc e (m ) 1 2 3 3 3 4 6 7 9 Downwin d Distanc e (m ) 1 5 2 1 3 0 3 0 3 6 4 7 6 3 7 8 9 7 Crosswind

Distanc e (m ) 1 1 2 2 2 3 4 5 7 Downwin d Distanc e (m ) 1 1 1 5 2 1 2 1 2 6 3 3 4 4 55 6 9 Crosswin d

Distanc e (m ) 1 1 1 1 2 2 3 4 5

S >

* Win d spee d 3. 0 meter s pe r second , atmospheri c stabilit y clas s D .120 0

100 0 —

8 0 0

C A k . o a > E **^ 9 O c ( 0 w Q 60 0 —

4 0 0

2 0 0 Exhibit5 QUANTIT Y RELEASE

D VERSU

S DISTANC

E FO R VAPO R CLOU D FIRES , INSTANTANEOU S RELEASES , MODERAT

E METEOROLOG

Y WHAZA N Modellin g fo r 1,000-50,000 Pounds , 50 % LFL

1 0

* Llqu.fl. d b y -•frlgtratio n
* * Liqu*fi* d unda r pr*(*ur • 

# fe

2 0 3 0 4 0 Quantit y Release d (thousand s o f pounds ) 5 0-23 -

WHAZA N modellin g wa s als o carrie

d ou tfo r th e te n chemical s show

n i n Exhibit4 usin g additiona l meteorological condition s o f win d spee d o f

1. 5 meter s pe r secon d an

d F atmospheri c stabilit

y a s inputs , for compariso n wit

h th e result

s obtaine d usin g th e averag e meteorological conditions . Th e WHAZA N result s fo r vapo r dou d fire

s appea r t o b e strongl

y dependen

to n th e meteorologica

l assumptions made , wit

h distance s determined usin g wors tcas e meteorolog y bein g muc

h greate r tha

n thos e resultin g from modellin g using moderat

e meteorology . Distance s for a concentratio n equa l t o 5 0 percen

to f th e LF L under wors tcas e meteorologica l condition s exten

d fro m 1,790 t o 635 0 meter

s fo r gases , compared t o 46 0 t o 1^9 0 meter

s unde r moderat

e conditions . Thes e result s are presente d i n Exhibi

tD-1 , Appendix D . Exhibi tD-1 , Appendi

x D , als o include s result

s o f WHAZA N modellin g for prolonge d release s o f te n chemicals , wher

e releas e wa

s assume d t o take place from 1.

5 inc h diameter hole s i n 1 2 foo tdiamete r tanks . Distance s t o th e 5 0 percento f th e LF L leve l fo r vapo r clou d fires ar e muc h smalle r (1 8 t o 7 9 meters ) tha

n for instantaneou s releases , indicating tha tusin g instantaneou s releas e condition s is , i n general , mor

e conservative tha

n usin g prolonge

d releas e conditions . 8 3 BLEV

E Result s Exhibi t6 present

s WHAZA N modellin g result s fo r BLEVE s o f

gase s (ethylene , propylene , propane , an d n-butane ) an

d for pentane , a volatil e liquid assume d t o b e store d unde

r pressure , fo

r releas e quantitie s o f 1,000 pound s t o 180,000 pounds . Distance s fo r thre e level s o f

heatradiation an

d th e duration o f

th e BLEVE s ar

e shown . Thes e dat

a ar e all importan

tcomponent

s i n analyzin

g th e consequence s o f

BLEVEs , which ar e a function- o f

exposure t o hea

tradiation level s for th e duration o f th e resultin g fireball. A s note d i n Sectio n 6.13 , pentan e an d lighter hydrocarbon

s hav e charaaeristic s (Le. , 1 0 percen to f th e chemica l vaporizes when i ti s released t o th e atmospher e fro m a vessel ) tha

tgiv e them a hig

h potential t o b e involve d i n BLEVE s (Nazari o 1988) . Whil e heavier hydrocarbon s ma y b e subje a t o BLEVE s under som e conditions , th e likelihoo d o f occurrenc

e o f a BLEVE i s muc

h smaller for suc

h chemicals ; therefore , WHAZA N BLEV E result s for hydrocarbon

s heavier than pentan e are no tincluded i n Exhibit6 . Th e mos tvolatil e o f

th e chemical s analyzed , ethylene , shows th e greates tdistances , an d th e leas tvolatile , pentane , th e smallest ; however, distances d o no tvar y greatl y from chemica

l t o chemical . Fo r releas e quantitie s o f

les s tha n 10,000 pounds , a

ta hea tradiation leve l o f

12. 5 kW/m

2 , distances for ethylen e var y from 8 2 meter

s for 1,00 0 pound s t o 179 meter

s for 10,00 0 pounds . Fo r pentane , th e range i s 5 6 meters for 1,00 0 pound s t o 12

0 meter s fo r 10,000 pounds . Th e duration o f

a BLEVE as estimated b y WHAZAN appear

s t o depen

d only o n th e quantit

y released ; i t doe s no tvar

y b y chemical . Fo r releas e quantities o f 10,000 pound s o r less , WHAZA N shows th e BLEV E duratio n t o rang

e from 8 second s for 1,00 0 pounds t o 1 7 second s fo r 10,00 0 pounds . A s note d earlier , th e WHAZA N manua

l (WHAZA N 1988 ) suggest s tha ta ta hea tradiation leve l o f

12.5 kW/m

2 , ther e woul d b e a 1 percen

tprobabilit

y o f fatalit y fo r a 3 0 second exposure . Therefore , fo r BLEVE s lastin g les s than 3 0 seconds , as i s th e cas e for BLEVE s involving quantities les s tha n 10,000 pounds , a highe r hea tradiatio n leve l mightb e o f

greater interes t(e.g. , 37. 5 kW/m 2 rather tha

n 12. 5 kW/m

2 ) , as exposur

e coul d no tlas t longe r than 2 0 seconds . Fo r a hea tradiation leve l o f 37. 5 kW/m

2 , distance s fo r ethylen e are 3 9 meter s fo r a 1,000 poun

d releas e an

d 10 3 meter s fo r a 10,00 0 pound release . Exhibit7 show

s WHAZA N results , presente d graphically , for BLEVE s o f 1,00 0 t o 50,00 0 pound s o f hydrocarbons . Th e grap

h o f released quantit

y versu s distance indicate s tha

tdistance i s proportiona

l t o th e cub e roo to f

quantity , as wa

s th e cas e fo

r vapor clou d explosions . ExhibitC-10 , i n Sectio n C3. 2 o f Appendi x C , present

s BLEVE results , i n graphica l form , from WHAZA N modellin g o f

tw o hydrocarbon

s fo r three hea

tradiation levels , t o tes tth e mode l result s fo r sensitivit

y t o vaiyin g hazar

d criteria levels . Fo r ethylen e an d propylene , usin g 37. 5 kW/m 2 rathe r tha n 12. 5 kW/m 2 appear s t o hav e a relativel

y smal l effe a o n results ; usin g 4 kW/m 2 rather tha

n 12. 5 kW/m2 appear

s t o have a greater effea .



### %P.3 1

-24 - Exhlbit 6 DISTANCES FO R BLEVE S FO R INSTANTANEOU

S RELEASE

S O F 1,00 0 T O 180,00 0 POUND S DETERMINE

D USIN G WHAZA

N Distanc e i n Meters to Thre e HeatRadiatio n Level s

Chemica l (Initia l Conditions )

Ethylen e (liquefie d b

y refrigeratio n 17 5 K , 1. 3 Bars )

Propylen e (liquefie d unde r pressur e 29 3 K , 13. 3 Bars )

Propan e (liquefie d b

y refrigeratio n 23 2 K , 1. 3 Bars )

n-Butan e (liquefie d unde r pressur e 29 3 K , 6. 3 Bars ) Quantit y Release d (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Distanc e t o

4. 0 kW/m 2 (m )

146 19 8 25 0 28 7 31 6 43 0 543 685 835 10 8 14 7 18 5 212 234 31 8 40 2 50 8 61 8 10 4 14 2 17 9 20 6 22 7 30 8 38 9 49 2 59 9 10 1 13 7 17 3 199 219 29 8 37 6 47 5 57 9 Distanc e t o

12. 5 kU/m 2 (m )

8 2 11 2 14 1 16 2 17 9 243 30 7 38 8 47 2 6 1 8 3 10 5 120 13 2 18 0 22 7 28 7 35 0 5 9 8 0 10 2 11 6 12 8 17 4 22 0 27 8 33 9 5 7 7 8 9 8 11 2 12 4 169 21 3 26 9 32 8 Distanc e t o

37. 5 kU/« 2 (m )

4 7 6 5 8 2 9 4 10 3 140 17 7 22 4 27 3 3 5 4 8 6 0 6 9 7 6 10 4 13 1 16 6 20 2 3 4 4 6 5 9 6 7 7 4 10 1 12 7 16 1 19 6 3 3 4 5 5 7 6 5 7 2 9 7 12 3 15 5 18 9 BLEV

E Duratio n (sec )

8 1 1 1 4 1 6 1 7 2 3 2 9 3 6 4 4 8 1 1 1 4 1 6 1 7 2 3 2 9 3 6 4 4 8 1 1 1 4 1 6 1 7 23 2 9 3 6 4 4 8 1 1 1 4 1 6 1 7 2 3 2 9 3 6 4 4



# q nP.3 2

-25 - Exhlbit6 DISTANCES FO

R BLEVE S FO R INSTANTANEOU

S RELEASE

S O F 1,00 0 T O 180,00 0 POUND S DETERMINE

D USIN G WHAZA

N Distanc e i n Meters to Three Hea tRadiatio n Level s (continued )

Chemica l (initia l Conditions )

Pentan e (29 3 K , 2.7 4 Bars ) Quantit y Release d (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Distanc e t o

4. 0 kW/m 2 On )

10 1 13 7 173 199 219 29 8 37 6 47 5 57 9 Distanc e t o

12. 5 kU/m 2 (m )

5 7 7 8 9 8 11 2 12 4 169 21 3 26 9 32 8 Distanc e t o

37. 5 kW/m 2 (m )

3 3 45 5 7 6 5 7 2 9 7 123 15 5 189 BLEVE

Duratio n (sec )

8 1 1 1 4 1 6 1 7 2 3 2 9 3 6 4 4



# tf c

## 35 0

30 0

25 0

( 0



## o u c ( 0 •#• " ( 0 

# 5 20 0

15 0

10 0

5 0 Exhibit7 QUANTIT

Y RELEASE

D VERSUS DISTANC

E FO R BLEVES , INSTANTANEOU S RELEASE

S WHAZA N Modellin g fo

r 1,000-50,000 Pounds , 12- 5 kW/m

2



## -H- - Ethylen e

- 0 Propylen e

- B Propane *



## - A n-Butane *



# ¥

1 0 2 0 3 0 4 0

Quantit y Release d (thousand s of pounds ) 5 0

* Liquefie d b y refrigeratio n
* * Liquefie d unda r preaeur e-27 -

WHAZA N modellin g wa s als o carrie

d ou tfo r BLEVE s usin g wors tcas e meteorological conditions . Vaiyin g th e meteorologica l condition s appeared t o have n o effea ; result s obtaine d were identica

l t o th e result s obtaine d using moderat e meteorologica

l conditions , indicatin g tha tmeteorologica

l condition s woul d b e expeae d t o hav

e littl e impa a o n th e consequence s o f BLEVEs . Result s are presente d i n ExhibitD-1 , Appendi x D . WHAZA N modellin g assumin g a prolonge d releas e fo r a BLEV E gave result s identica l t o thos e assuming a n instantaneou s release , as show n i n ExhibitD-1 , Appendi x D . A s BLEVE s resultfrom sudden vesse l failure , the

y woul d alway

s b e essentially instantaneous ; therefore , i ti s no tclear tha tan y distinctio n ca

n b e mad e betwee n instantaneous versus prolonge d releas e inputi n modellin g BLEVEs . 8. 4 Poo l Fire Result s Exhibit8 present

s WHAZA N modellin g result s fo r poo l fire

s resultin g from release s o f 1,00 0 t o 180,00 0 pound s o f te n hydrocarbons . Distance s are give n fo r thre e level s o f heatradiation . Th e initial quantit y i n th e poo l an

d th e duratio

n o f th e fir e ar e als o provided . Fo r al l th e chemical s show n i n Exhibi

t8 , distance s for release s smalle r tha n 10,00 0 pound

s ar e les s tha n 100 meters . Th e distanc

e result s for poo l fire

s d o no tvar

y greatl y b y chemical , possibl

y becaus e al l o f

th e chemical s show

n her e ar e hydrocarbons , an

d al l hav e similar heat

s o f combustion . (WHAZA N produce d somewha tsmaller distances fo

r a give n quantit y o f severa l organi c chemical s wit

h differin g heat s o f combustion ; se e Exhibi

tD-1 , Appendi

x D. ) Ethylen e an

d propane , th e tw

o gase s assume

d liquefied b

y refrigeration , show greate r distances tha

n propylene an

d n-butane , gase s assume

d t o b e liquefied under pressure . Large

r quantities o f

th e pressurize

d gase s flash into vapo r o n releas e tha n fo r th e refrigerate

d gases ; therefore , th e quantit y i n th e poo l woul d b e larger fo r th e refrigerate

d gases , an

d th e greater distance s woul d b e expeaed . Th e poo l fire duratio

n dat a rang e from about2 0 second s fo r 1,00 0 pound s o f

propylene t o approximatel y 2 minute s fo r 180,00 0 pounds o f p-xylene . Afte r tha

ttim e th e materia

l i n th e poo l i s consumed , extinguishing th e poo l fire . Th e dat a fo r a specifi c quantit

y an d hazar d criteria leve l ar

e fairl y consisten t from chemica

l t o chemical . Th e WHAZA N poo l fire result s ar e presente d graphicall

y i n Exhibit9 fo

r release s o

f 1,00 0 t o 50,00 0 pounds . Th e grap

h o f quantit y released versus distance indicates tha tdistance i s proportiona

l t o th e cub e roo to f th e quantit

y released , a

s wa s th e cas e for vapor clou d explosion s an d BLEVEs . ExhibitC-ll , i n Sectio n C3. 2 o f Appendi x C , present

s WHAZA N modellin g results , i n graphica l form , for ethylen e an

d propylene , showin

g th e effe a o f

using differen

thea tradiation levels . A s wa

s th e cas e for BLEVEs , using a differen thea tradiation leve l appear

s t o hav e a greater effe a o n distanc e atlowe r level s tha n a thigher levels . Th e grap

h indicate s tha

tbasin g result s o n 1 0 kW/m

2 , as i n ARCHIE modellin g (se e ExhibitD-1 , Appendi

x D) , rather tha

n 12. 5 kW/m

2 , probabl y doe s no thav

e a grea teffe a o n th e results . WHAZA N modellin g o f

poo l fires for te n chemical s usin g worstcas e meteorology gav e result s identical t o thos e obtaine d using moderat e meteorology , indicatin g tha tmeteorologica

l condition s probabl

y d o no t hav e muc h effe a o n poo l fir

e consequences . Thes e result s ar e presented i n ExhibitD-1 , Appendi x D . WHAZA N poo l fir

e result s fo r prolonged release s (assumin g releas e from a hol e wit

h a diamete r o f

1. 5 inches ) o f 100,000 pound

s o f te n chemical s ar

e presented i n Exhibi

tD-1 , Appendi

x D ; result

s for instantaneou s release s ar

e als o included fo r comparison . Distance s for prolonge d release s are muc h smaller ( 9 t o 2 3 meter

s compare d t o 15 2 t o 182 meters ) tha n fo r instantaneou s releases , again indicatin g tha tth e inpu to f instantaneous releas e typ e i s mor e conservativ

e tha n assumin g a prolonged release .



# \5 D-28 - Exhlbit 8 DISTANCES FO

R POOL FIRE S FO R INSTANTANEOU

S RELEASE

S O F 1,000 TO 180,00 0 POUND S DETERMINE

D USIN G WHAZA

N Distanc e i n Meters to Thre e HeatRadiatio n Level s

Chemica l (Initia l Conditions )

Ethylen e (liquefie d b y refrigeratio n (17 5 K , 1. 3 Bars )

Propylen e (liquefie d unde r pressur e 29 3 K , 13. 3 Bars )

Propan e (liquefie d b y refrigeratio n 23 2 K , 1. 3 Bars )

n-Butan e (liquefie d unde r pressur e (29 3 K , 6. 3 Bars ) Quantit y Release d (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Quantit y

I n Poo l (lbs )

97 7 2,44 8 5,00 0 7,32 1 9,76 8 24,47 6 46,52 6 97,68 2 175,73 9 65 0 1,67 8 3,35 2 5,02 7 6,48 3 16,22 9 32,41 4 64,82 7 116,86 5 98 6 2,47 0 4,91 7 7,38 7 9,85 6 24,69 6 49,17 2 98,56 4 177,28 2 85 8 2,22 7 5,00 5 6,65 9 8,57 7 21,43 3 42,77 7 85,77 5 154,35 0 Poolfir e

Radiu s (m )

1 1 1 5 1 9 2 3 2 5 3 6 4 6 6 0 7 4 9 1 3 1 7 2 0 2 1 3 0 3 9 5 1 6 4 1 0 1 5 1 9 2 2 2 5 3 5 4 5 5 8 7 3 1 0 1 4 1 8 2 1 23 3 2 4 2 5 4 6 7 Distanc e t o 1. 6 kW/m 2 (m )

112 15 1 19 0 21 7 23 8 32 1 40 3 50 6 614 10 0 136 17 0 194 21 1 28 4 35 6 44 7 54 2 11 4 15 3 192 21 9 24 1 32 4 40 7 51 1 62 0 110 15 0 18 8 21 4 23 2 31 3 39 3 49 3 59 8 Distanc e t o

4. 0 kW/tn 2 (tn )

7 2 9 6 12 0 13 7 15 0 20 3 25 5 32 0 38 8 6 3 8 6 10 8 12 3 13 3 180 22 5 28 3 34 3 7 2 9 7 12 1 13 9 15 2 20 5 25 7 32 3 39 2 7 0 9 5 11 9 13 5 14 7 19 8 24 9 31 2 37 8 Distanc e t o 12. 5 kW/m 2 (m )

4 0 5 4 6 8 TT 8 5 11 5 14 4 18 1 22 0 3 6 4 9 6 1 6 9 7 5 10 2 12 8 16 0 194 4 1 5 5 6 9 7 8 8 6 11 6 146 18 3 22 2 3 9 5 4 6 7 7 7 8 3 11 2 14 1 17 6 21 4 Poolfir e Duratio n (sec )

2 6 3 2 3 8 4 2 4 5 5 7 6 8 8 1 9 4 2 2 2 8 3 3 3 6 3 9 4 9 5 8 6 9 8 0 2 5 3 1 3 7 4 1 4 4 5 5 6 5 7 8 9 0 2 3 2 9 3 5 3 8 4 1 5 1 6 1 7 3 8 4



# 10

1-29 - Exhlbit 8 DISTANCES FOR POO

L FIRE S FO R INSTANTANEOU

S RELEASE

S OF 1,000-180,000 POUND S DETERMINE

D USIN G WHAZA

N Distanc e i n Meter s to Thre e HeatRadiatio n Level s

(continued )

Chemica l (Initia l Conditions )

Pentan e (29 3 K , 2.7 4 Bars )

Gasolin e (29 3 K , 1.01 3 Bars )

Hexan e (29 3 K , 1.01 3 Bars )

Heptan e (29 3 K , 1.01 3 Bars ) Quantit y

Release d (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5.00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Quantit y

I n Poo l (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Poolfir e

Radiu s (m )

1 0 1 4 19 2 2 2 4 3 4 45 5 8 7 2 1 0 1 4 18 2 2 24 3 4 4 4 5 7 7 1 1 1 1 5 1 9 2 2 2 5 3 5 4 6 5 9 7 4 1 1 1 5 2 0 2 3 2 6 3 6 4 7 6 1 7 6 Distanc e t o

1. 6 kW/m 2 (m )

11 4 15 3 19 2 219 24 0 32 4 40 6 51 0 61 8 10 9 14 6 18 4 20 9 23 0 31 0 38 9 48 8 59 2 108 14 6 18 3 20 9 22 9 30 9 38 8 48 8 59 2 10 4 140 17 5 20 0 22 0 29 7 37 3 46 9 56 9 Distanc e t o

4. 0 kW/m 2 (m )

7 2 9 7 12 1 13 8 15 2 20 5 25 7 32 2 39 1 6 9 9 3 11 6 132 14 5 19 6 246 30 9 37 5 6 9 9 2 11 6 132 14 5 19 6 24 6 30 8 37 4 6 6 8 8 1 1 12 7 139 18 8 23 6 29 7 36 0 Distanc e t o 12. 5 kV/m 2 (m )

4 1 5 5 6 9 7 8 8 6 11 6 14 5 18 2 22 1 3 9 5 2 6 6 7 5 8 2 11 1 13 9 17 5 212 3 9 5 2 6 5 7 5 8 2 11 1 13 9 17 4 21 2 3 7 5 0 6 3 7 2 7 9 10 6 13 4 168 204 Poolfir e

Duratio n (sec )

2 5 3 1 3 7 4 1 4 4 55 6 6 7 8 9 1 2 6 3 3 3 9 4 3 4 6 5 8 6 9 8 2 9 5 2 7 3 4 4 0 4 4 4 8 6 0 7 1 8 5 9 8 2 9 3 6 4 3 4 8 5 2 65 7 7 9 2 106



## . 0 ^-30 - Exhlbit 8 DISTANCE

S FO R POO L FIRE S FOR INSTANTANEOU

S RELEASE

S O F 1,000-180,000 POUND S DETERMINE

D USING WHAZA

N Distanc e i n Meters to Three HeatRadiatio n Level s

(continued )

Chemica l (Initia l Conditions )

Toluen e (29 3 K , 1.01 3 Bars )

p-Xylen e (29 3 K , 1.01 3 Bars ) Quantit y

Release d (lbs)

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Quantit y

I n Poo l (lbs )

1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 1,00 0 2,50 0 5,00 0 7,50 0 10,00 0 25,00 0 50,00 0 100,00 0 180,00 0 Poolfir e

Radiu s (m )

1 1 1 5 2 0 23 2 6 3 6 4 7 6 0 7 5 1 1 1 5 2 0 23 2 6 3 7 4 7 6 1 7 6 Distanc e t o

1. 6 kW/m 2 (m )

9 5 12 8 16 0 18 3 20 1 27 2 33 8 42 9 52 0 9 4 12 7 15 9 18 1 19 9 26 9 33 8 42 5 51 7 Distanc e t o 4. 0 kW/m 2 (m )

6 0 8 1 10 1 11 6 12 7 17 2 21 4 27 1 32 9 5 9 8 0 10 1 11 5 126 17 0 21 4 26 9 32 7 Distanc e t o 12. 5 kW/m 2 (m )

3 4 4 6 5 7 65 7 2 9 7 12 1 15 3 186 3 4 4 5 5 7 6 5 7 1 9 6 12 1 15 2 18 5 Poolfir e

Duratio n (sec )

3 2 4 0 4 8 5 3 5 7 7 1 8 7 10 0 11 7 3 3 4 1 4 9 5 4 5 8 7 3 8 7 10 3 11 9



# \C 315 0

12 5

10 0 —
c o

_ . a > 0 ) E o c n

_ £ Q 7 5

5 0

2 5 Exhibi t 9 QUANTIT Y RELEASE

D VERSU S DISTANC E FO R POO L FIRES , INSTANTANEOU S RELEASE S WHAZA N Modellin g fo r 1,000-50,00

0 Pounds , 12. 5 kW/m 2

1 0 2 0 3 0 4 0

Quantit y Release d (thousand s o f pounds ) —^-^^^^^xX^

— Wj

I I I * -r - Ethylen e

* * O Propylen e

* D Propan e <^- i n-Butan e

• Pentan e

• Gasolin e

- ^ Hexan e I I

5 0 t* >

* Liquefie d b y refrigeratio n
* * Liquefie d unde r pressur e-32 - 8. 5 Je tFire Result s Exhibi t1 0 present

s WHAZA N result

s for je tfires , whic

h ar e define d b y th e model a s prolonge d releases . Results wer e obtaine d onl y for two gase s (propylen e an d n-butane ) assume

d t o b e store d under pressur e at ambien ttemperature . Results fo r release s o f

10,00 0 pound s an

d thre e hea

tradiatio n level s are show n alon g wit h th e duration o f

th e je tfire. Distance s fo r 10,00 0 poun d release s o f

n-butane wer e les s tha

n 2 5 meter s fo r a al l thre e hea tradiation level s modelled . Fo r propylene , th e distance s range d from 3 5 meter

s at37. 5 kW/m

2 t o 5 1 meter

s at4. 0 kW/m

2
. Th e duratio n o f

th e releas e (an

d presumabl

y o f th e je tfire ) woul d b e approximatel

y on e hou r for th e n-butane je tfire an d about1 5 minute s for th e propylen e je tfire. Fo r bot h o f thes e gases , th e othe r type s o f accident s modelle d gav

e muc h greater distance s tha

n je tfires. A s detaile d i n ExhibitD-1 , Appendi x D , je tfires for 100,00 0 poun d release s o f

n-butane an

d propylene produce distanc e result

s almos tidentica

l t o th e result

s fo r 10,00 0 pound releases . However , th e duration o f th e je tfires fo

r th e 100,00 0 poun

d release s wa

s muc h greater . Not e tha

tfor a n instantaneou s releas e o f thes e gases , th e possibl e resul twoul d b e a vapo r clou d explosio n o r fire, no ta je tfire. 9. 0 Finding s Base d o n th e result

s o f modellin g flammabl

e hazard s usin g th e WHAZA N model an d analysis o f

th e literature , a clear distinctio n ca n b e mad e betwee n th e result

s for flammabl

e substances tha

tboi l athigher temperature

s tha n pentan e an

d flammable substances tha tboi l a tlowe r temperatures tha

n pentane . Thi s would sugges ta distinctio n exist s a troughl y 310° K - 315° K (37° C - 42°C) . Analysi s o f othe r classificatio n schemes an

d regulation s (se e Seaio n 3 ) shows tha tflammable gase s an

d volatil e flammable liquid s appea r t o b e th e flammable materials considered o f greates tconcer

n b y agencies an

d organizations suc

h as DOT , NFP A an d EE C Th e temperatur

e atwhic h clear distinction s i n consequence s ca n b e made corresponds t o th e temperatur

e a twhic h DO T an

d NFP A hav e made distinction s i n categorie s o f flammabl

e materials (boilin g poin tbelo w 38° C an d flash poin tbelo w 23° C for NFP A flammability rating 4 ; boilin g poin tbelo w 35° C an d flash poin tbelo w 23° C fo r DO T Packin

g Grou p I) . Thi s temperatur

e als o correspond s t o ver

y hig h ambien ttemperatures (38° C i s roughl y 100°F) ; i ti s possibl e fo

r substances wit

h boilin g points les s tha n 37° C - 42° C t o b e gase s unde r ambien tconditions . Therefore , flammable gase s an d ver y volatil e flammable liquid s (includin g substance s tha tboi l attemperatures les s tha n about42°C ) appea

r t o b e th e mos tlikely candidates fo

r furthe r consideration . Exhibi t1 1 identifie s 6 9 flammable gases (boilin g poin tato r belo w 20°C) . Thi s lis tinclude s mos t flammable gase s currentl y i n commerce . Eighto f

thes e substances ar

e regulated a

s extremel y hazardou

s substances (EHSs ) o n th e basi s o f toxicit y an d ar e indicate d i n th e exhibitb y a n asterisk . Th e substances i n thi s exhibitar

e gase s tha

thav e NFP A flammability rating

s o f 4 (NFP A 1984 ) o r ar

e liste d b y DO T as flammable gase s i n cunen tDO T regulations (U.S . DO T 1984 ) o r i n DOT s propose d rul e (U.S . DO T 1987) . (Not e tha

tthere are discrepancie

s i n th e rating

s o f a fe w chemicals , e.g. , viny

l bromid e i s liste d as a flammable ga

s b y DO T bu

tconsidered non-flammable b y th e NFPA ) Liquid

s tha tboi l clos e t o ambien

t temperatur

e ma y vaporiz e readil

y an d als o ma y for m vapo r clouds . I

f th e flash points o f

suc h liquid s ar

e ato r belo w ambien

ttemperature , th e vapor ma y ignite under ambien

tcondition s an

d vapo r clou d fires o r explosion s ma

y occur . Exhibit1 2 show s 2 8 liquid s tha

tboi l belo w 38° C an

d have flas

h point s lowe r tha

n 23° C (i.e. , thei r flash points ar e a to r belo w norma

l ambien ttemperature) . Thre e o f them (indicated b

y a n asterisk i n th e exhibit

) ar e liste d a s EHS s becaus e o f

toxicity . Th e substances i n thi s exhibithave NFP A flammability ratings o f

4 (NFPA 1984 ) o r appea r t o mee tth e criteria for thi s rating o n th e basi s o f flas h pointan d boilin g point . Chemical s wit h highe r boilin g point

s (38° C an

d above ) wit

h flash points a

to r belo w ambien

ttemperatur

e wil l no tvaporiz e readil

y unde r ambien tconditions , bu

tma y ignit e an d burn. Fo r thes e chemicals , poo l fire s ar e a mor e likely even ttha

n vapor clou d fire

s an d explosions . Modellin g indicate s tha tpoo l fires ar

e les s hazardou

s tha n vapo r clou d fire

s an d explosions , based o n th e distanc e results . Ove

r 35 0 liquid s wit

h boilin g point

s o f 38° C o r higher an

d flash points belo w 23° C hav e bee n identified , includin g man y common , high-volum e substance s suc h a s gasoline , benzene , toluene , an d th e xylenes .


# \Q 5P.4 0
-33 - Exhlbit1 0 DISTANCES FOR JE T FIRE S FO R PROLONGE

D RELEASE

S O F 10,00 0 POUND S DETERMINE

D USIN G WHAZA

N Distanc e i n Meters to Thre e HeatRadiatio n Level s

Chemica l (Initia l Conditions )

Propylen e (liquefie d unde r pressur e 29 3 K , 13. 3 Bars ) Quantit y Release d (lbs )

10,00 0 Distanc e t o

4. 0 kU/m 2 (a )

5 1 Distanc e t o

12. 5 kW/m 2 (m )

4 0 Distanc e t o

37. 5 kW/m 2 (m )

3 5 Je t Fir e

Duratio n (min )

1 5

n-Butan e 10,00 0 (liquefie d unde r pressure 29 3 K , 6. 3 Bars ) 2 5 1 9 1 7 6 0



# \0 kEH S P.4 1

-34 - Exhlbi t1 1 FLAMMABL E GASE S

CAS #Chemica

l 74-86- 2 ACETYLEN

E 7784-42- 1 ARSINE * 598-73- 2 BROMOTRIFLUORETHYLEN E 75-63- 8 BROMOTRIFLUOROMETHAN E 106494 ) 1,3-BUTADIEN E 75-28- 5 ISOBUTAN

E 106-97- 8 BUTAN E 590-18- 1 2-BUTENE-CI S 624-64- 6 2-BUTENE-TRAN S 10648- 9 ALPHA-BUTYLEN E 107-01- 7 BETA-BUTYLEN E 25167-67- 3 BUTYLEN

E 630-08- 0 CARBON MONOXID E 463-58- 1 CARBON OXYSULFIDE 7791-21- 1 CHLORIN

E MONOXIDE 460-19- 5 CYANOGE

N 506-77- 4 CYANOGE

N CHLORID

E 287-23- 0 CYCLOBUTAN E 75-19^ 1 CYCLOPROPAN E 778i394 > DEUTERIU

M 19287-45- 7 DIBORANE * 4109-96- 0 DICHLOROSILAN E 75-68- 3 DIFLUORO-1-CHLOROETHAN E 75-37- 6 DIFLUOROETHAN E 124-40- 3 DIMETHYLAMIN E 463-82- 1 2^-DIMETHYLPROPAN E 74-84- 0 ETHANE 107-00- 6 ETHY

L ACETYLEN

E 75-04- 7 ETHYLAMIN

E 75-00- 3 ETHY

L CHLORID

E 74-85- 1 ETHYLEN

E 75-21- 8 ETHYLEN

E OXIDE * 353-36- 6 ETHY

L FLUORID E 540-67- 0 ETHYL METHY L ETHE R 109-95- 5 ETHY

L NITRIT

E 50-00- 0 FORMALDEHYDE * 7782-65- 2 GERMAN

E 1333-74- 0 HYDROGE N 77834)7- 5 HYDROGE N SELENIDE * 77834)6- 4 HYDROGE N SULFIDE * 64741-48- 6 UQUEFIE D NATURA L GA S 68476*5- 7 UQUEFIE D PETROLEU M GA S 74-82- 8 METHAN

E 74-89- 5 METHYLAMIN E 563-45- 1 3-METHYL-l-BUTENE 74-87- 3 METHY

L CHLORID

E Boiline Poin tCO -8 3 -6 3 -5 9 -4. 4 -1 2 -0_ 5 3. 7 0. 9 -6. 5 1. 0 -6 3 -19 2 -5 0 4 -2 1 1 3 1 3 -3 3 -25 0 -9 3 8 3

- 9 -2 5 7 9.5 -8 9 1 7 1 2 -10 4 1 1 -3 8 1 1 1 7 -2 0 -88 -25 3 ^» 1 -6 0 -15 9 •40 -162 -6 3 2 0 -24



# Kf

tP.4 2

-35 - Exhlbit1 1 FLAMMABL

E GASE S (continued )

CAS #Chemica

l 115-10- 6 METHY

L ETHER 593-53- 3 METHY

L FUJORID E 74-93- 1 METHY

L MERCAPTAN * 115-11- 7 2-METHYLPROPEN E 8006-14- 2 NATURA L GA S 68476-26- 6 OI

L GA S 504-60- 9 13-PENTADIEN E 7803-51- 2 PHOSPHINE * 463-49- 0 PROPADIEN

E 74-98- 6 PROPAN

E 115-07- 1 PROPYLEN

E 74-99- 7 PROPYN

E 7803-62- 5 SILAN

E 116-14- 3 TETRAFLUOROETHYLEN E 79-38- 9 TRIFLUOROCHLOROETHYLEN E 42<M6- 2 1,1,1-TRIFLUOROETHAN E 75-50- 3 TRIMETHYLAMIN E 689-97- 4 VINY L ACETYLEN E 593-60- 2 VINY L BROMIDE 75-01- 4 VINY L CHLORIDE 75-02- 5 VINY L FLUORID E 75-38- 7 VINYLIDEN

E FLUORID E 107-25- 5 VINY L METHY L ETHER Boilin e Poin tCO -2 4 6

- 7

-4 3 -8 8 -3 5 -4 2 -4 8 -2 3 -11 1 -7 6 -2 8 -4 8 3 5 1 6 -1 3 -7 2 -8 3 1 2

EH S Sources : NFP A 1984 , U.S

. DO T 1984 , U.S

. DO T 1987

.



# \0 %-36 - Exhibitl 2 FLAMMABLE

, VOLATIL

E UQUID S

CA S • # Chemica l

75-07- 0 ACETALDEHYD E 627-20- 3 AMYLENE , beta-,ci s 646-04- 8 AMYLENE , beta-,tran s 7S-91- 2 TERT-BUTY

L HYDROPEROXID

E 503-17- 3 2-BUTYH

E SS7-98- 2 2-CHLOROPROP_l__H E 590-21- 6 1-CHLOROPROPYLEH E 75-18- 3 DIMETHY

L SULFID E 60-29- 7 ETHY

L ETHER 7S-08- 1 ETHY

L MERCAPTA

N 110-00- 9 FURAN * 74-90- 8 HYDROGE

N CYANIDE * 78-79- 5 ISOPREN

E ISOPROPENY

L ACETYLEN

E 563-46- 2 2-METHYL-I-BUTEN E 563-45- 1 3-METHYL-l-BUTEH E 107-31- 3 METHY

L FORMAT E 78-78- 4 ISOFENTAN

E 109-66- 0 PENTAN

E 109-67- 1 1-PENTEN

E 8030-30- 6 PETROLEU M NAPHTH A 7S-31- 0 ISOPROPYLAMIN E 7S-29- 6 ISOPROPY

L CHLORIDE 75-56- 9 PROPYLEN

E OXIDE * 7S-76- 3 TETRAMETHYLSILAN E 1002S-78- 2 TRICHLQROSILAN E 109-92- 2 VINY

L ETHY L ETHE R 75-35- 4 VINYLIDEN

E CHLORIDE Boilin g Point C O 2 0 3 7 3 6 3 5 2 7 2 3 3 3 3 7 3 5 3 4 3 2 2 6 3 4 3 3 3 1 3 7 3 2 2 8 3 6 3 0 3 5 3 2 3 6 3 4 2 6 3 2 3 6 3 2 Flas h Poin t



### rc - -3 6 <-2 0 <-2 0 <2 7 <-2 0 <-2 0 <- 6 -3 8 -4 5 -1 8 -1 8 -5 4 <- 7 <- 7 <- 7 -3 2 -5 7 -4 9 -1 8 -1 8 -2 6 -3 2 -3 7 -1 4 -4 6 -2 8

EH S Sources : NFP

A 1984 , U.S . DO T 1984 , U.S . DO T 1987 .



# p 9-37 -

Fo r vapo r clou d explosions , BLEVEs , an d poo l fires, th e distance for a give n hazar d criterio n leve l i s proportiona

l t o th e cub e roo to f

th e quantit

y release d (Le , doubling th e quantit y o f chemica l use d i n th e analysis doe s no tdoubl e th e distance , bu tincrease s i tb

y a faao r o f

abou t1.26 , th e cub e roo to f

2) . Fo r vapo r clou d fires, th e distanc e i s no tdirectl y proportiona

l t o quantity , th e exac

trelationshi p i s no tknown , butth e quantit

y versu s distanc e curv

e (se e Exhibit5 ) i s similar i n shap e t o th e curve s showing th e cub e roo trelationshi p (se e Exhibit s 3,7 , an d 9) . Fo r a give

n quantit y o f a flammabl

e chemical , distance s for al l type s o f accident s depend o n th e hazar

d criterio n leve l chose n for us e i n th e analysis ; Le, th e overpressur e level (fo r vapo r clou d explosions) , concentratio n (fo r vapo r dou d fires), o r heatradiatio n leve l (for BLEVEs , poo l fires, an d je tfires). Th e greates tdistance s calculate d usin g th e WHAZA N mode l resulted fro

m vapo r clou d explosion s an d vapo r clou d fires o f

gase s an d ver y volatil e liquids . Vapo r clou d explosion s hav e bee n described a s unlikel y fo r doud s containin g les s tha n 10,00 0 pound s o f

flammable ga

s (AP I 1990) . A s note d earlier , th e effect s o f vapo r dou d fires ar

e likel y t o b e limite d t o a muc h smalle r cross-sectiona

l are a tha n th e effect

s o f vapo r clou d explosions , sinc e person s woul d have t o b e i n th e pat h o f th e engulfing fire for fatalitie s t o occur . Th e vapo r dou d explosio n result s vai y depending o n th e overpressur e considered ; a

toverpressures o f

3. 0 ps i an d higher , modellin g showed greate r distance s for BLEVE s tha n fo r vapo r clou d explosions . Poo l fires appea

r t o produc

e more localize d consequence s tha n vapor clou d explosions , vapor clou d fires, an d BLEVEs . Th e consequenc e analysis result s d o no ttake int o accoun tth e likelihoo d tha

ta particula

r typ e o f consequence , suc

h as a vapo r dou d explosion , wil l resul tfro m a particula

r acdden tTh e specifi c circumstance

s surroundin

g a n acdden t(e.g. , amoun

to f materia l involved ; releas e type , suc h as storage , processing , transfer, transport ) an d th e specifi c condition s (e.g. , tim e o f day, local meteorology an d climate , proximit y an d typ e o f population ) atth e tim e o f a n acdden tma

y hav e significan

teffect s o n th e severit

y an d rang e o f consequences . Modellin g canno ttak e al l circumstance s an d condition s int o account . Th e modellin g als o indicate s tha tmeteorologica

l condition s ca

n hav e a majo r effec to n th e consequence s o f vapo r clou d fires, based o n th e dispersio n o f th e flammable cloud , whic h impact s bot h distanc e travelled an d concentration . Storage temperature s o f liquefied gases ma

y hav e a significan

teffec to n consequenc e ' result s fo r ga s releases ; a

textremel y col d storag e temperatures , muc h les s o f th e ga s wil l flash o n release . Based o n th e result

s fo r prolonge d release s under th e condition s modelled , i tappear s tha tinstantaneou s release s hav

e consequence s atgreater distance s tha n prolonged releases . Th e greates tdistance overall calculate d usin g th e WHAZA N mode l fo r a n instantaneous releas e o f 10,00 0 pound s wa

s fo r a vapo r clou d explosio n o f propylene liquefied unde r pressure . Th e distance for a n overpressur

e o f 0. 3 ps i wa

s 80 0 meters ; however, thi s overpressur e i s probabl

y to o lo w t o caus e seriou s injuiy . Fo r a

n overpressur

e o f 1. 0 psi , modellin g produce

d a distanc

e o f 30 0 meter

s fo r a 10,000 poun d releas e o f propylene . Note , however, tha ta 10,000 poun

d releas e unde

r th e condition s modelle d woul d produce a clou d containin g approximatel y 330 0 pound s o f

propylene , a quantit

y tha twoul d hav

e a lo w probabilit y o f explodin g (Prug

h 1987) . Vapo r clou d fire result s fo r a 10,00 0 poun d releas e o f

ethylene , base d o n dispersio n t o a concentratio n equa l t o 5 0 percen

to f th e LFL , indicated a downwin d distance o f 55 0 meters , whic

h i s greater tha

n th e vapo r clou d explosio n distance o f 30 0 meter

s for 1. 0 psi ; however , th e are a withi n whic

h th e vapo r clou d woul d b e flammabl e (an d hence fata

l t o anyone i n th e fire zone ) i s muc h smalle r tha

n th e are a tha twoul d b e subjeae d t o a n overpressur

e o f 1. 0 ps i o r greater i n cas e o f a vapo r clou d explosion .



# 11 0-38 -

Reference s AIChE . 1987 . America

n Institut e o f Chemica l Engineers . Method s for Calculatio n o f Fir e an d Explosion s Hazards . New York : AICh E AP L 1990 . America

n Petroleum Institute . Managemen to f Proces s Hazards . Productio n an d Refinin g Departments . .AP

I Recommended Practice 750 . Washington , D.C : API ASTM . 1969 . America

n Sodet y for Testin g an

d Materials . Standar

d Metho d o f

Tes tfor Flas h Poin to f Volatil e Flammable Material s b y Tag Open-Cu p Apparatus . Burea u fo r Industria

l Safet y (TNO) . 1980 . Method s fo r th e Calculation o f th e Physica

l Effect s o f th e Escap e o f Dangerous Materia

L Rijswijk, Netherlands : TN O (Commissioned by : Directorate-Genera l o f Labour) . Brasi e W. , Simpson , D . 1968 . "Guideline s Fo r Estimatin g Damage Explosion, " AICHE Symposiu m o n Los s Preventio n i n th e Proces s Industries , Februar y 18-23,1968 . CCPS . 1989 . Center fo

r Chemica

l Proces s Safet

y o f th e America

n Institut e o f Chemica l Engineers . Ne w York : America

n Institut e o f Chemica l Engineers . EE C 1982 . Europea

n Economi c Community . Officia l Journa l o f th e Europea

n Communities , Volum e 25 , L230 . Counci

l Directiv e o f

2 4 Jun e 1982 o n th e majo

r acdden thazard

s o f certain industria

l activities . Eichle r T. , Napadensky, H . 1977 . "Acddenta l Vapo r Phas e Explosion s o n Transportation Route s Near Nuclea r Plants, " IT

T Researc

h Institute , Prepare

d for Argonn e Nationa

l Laboratory . Apri l 1977 . Eisenberg N A e tal . 1975 . Vulnerabilit y Model . A Simulatio n Syste m fo r Assessin g Damag e Resultin g fro m Marin e Spills . NTIS AD-A015-245 . Springfield , V A Greleck i C "Fundamental

s o f Fire an d Explosio n Hazard

s Evaluation, " C Grelecki , Hazard s Researc h Corp. , AICHE Toda

y Series . HCHAP . 1989 . Handbook o f Chemica l Hazar d Analysi s Procedures . Federa l Emergenc

y Managemen

t Agency , U.S . Departmen

to f Transportation , U.S . Environmenta l Protectio n Agency . Lewi s DJ . 1980 . Unconfine d Vapor-Cloud Explosions-Historica l Perspective an d Predictive Metho d Base d o n InddentRecords . Prog . Energ y Comb . Sd. , Vol . 6 . Grea tBritain : Pergamo

n Pres s Ltd . McRae T . 1984 . "Th

e Effect s o f Larg e Scal e LNG/Water RP T Explosions, " McRae , T.G. , etaL , Lawrenc e Livermor e Nationa l Laboratory . April 27,1984 . MHiAT . 1985 . Manua

l o f Industria l Hazar d AssessmentTechniques . Offic e o f Environmenta

l an d Sdentifi c Affairs , Th e Worl d Bank . Muda n KS . 1984 . Therma

l Radiatio n Hazard

s from Hydrocarbo

n Poo l Fires . Prog . Energy . Combust . Sd . 1984 , Vol . 10 . Grea

tBritain : Pergamo

n Pres s Ltd . Nazari o NN . 1988 . Preventing o r Survivin g Explosions . Chemica

l Engineering , Augus t15,1988 . NFP A "Fir

e Proteaio n Handbook, " 16t h edition , Nationa

l Fire Proteaio n Assodatio n (NFPA) . NFP A 1984 . Nationa

l Fire Protectio n Assodation . Fire Protectio n Guid e o n Hazardou s Materials , 8t

h ed . Quincy , M A NFP A 

# H I-39 -

Prug h RW . 1987 . Evaluatio n o f Unconfine d Vapo r Qou d Explosio n Hazards , Internationa l Conference o n Vapo r Qou d Modelling , Cambridge, M A November 2-4,1987 . Richmon d D . 1968 . "Th

e Relationshi p Betwee n Seleae d Blast-Wav e Parameter

s an d th e Respons e o f Mammals Expose d t o Ai r Blast " Richmond DR , Damo n EG , Fletche r ER , Bowe n IG , Whit

e CS. , Ann . N.Y . Acad . ScL , 1968 . Sa x NI , Lewi s RJ . 1987 . Hawley' s Condensed Chemica l Dictionary , llt h ed . New York : Van Nostrand Reinhol d Co . SkarkaJ . 1987 . Considerations o f Maximu m Hazar d limit s Originating fro

m LP C Processin g an

d Handling , Internationa

l Conferenc

e o n Vapo r Qou d Modelling , Cambridge, M A November 2-4,1987 . Technica l Guidance . 1987 . Technica l Guidanc e for Hazard

s Analysis , Emergenc

y Plannin g for Extremel

y Hazardou s Substances . U.S . Environmenta l Protectio n Agency , Federa l Emergenc

y Managemen

tAgency , U.S . Departmento f

Transportation . U.S . Ai r Forc e 1983 . "Explosive s Safet y Standards, " A F Regulatio n 127-100,2 0 Ma y 1983 . U.S . DO T 1984 . Hazardou s Material s Table . 4 9 CF R 172,101 . U.S . DO T 1987 . Proposed Rulemaking . 5 2 FR 42787-42931 , November 6,1987 . U.S . DO T 1988 . "Hazar

d Analysi s o f

Commercia

l Spac e Transportation, " Offic

e o f Commercia

l Space Transportatio n Licensin g Program s Division , U.S . Departmen to f Transportation . Ma

y 1988 . USEP A 1988 . U.S . Environmenta l Protectio n Agency . Acute hazardou s event s dat a bas e (1988) . Draf

t fina l repor tPrepare

d b y Industria

l Economics , Inc. EP

A Contra a No . 68-W8-0038 . WHAZAN . 1988 . WHAZA N Use r Guide . Technic a Internationa

l Ltd . Wiekem a BJ. 1984 . Vapo r Qou d Explosion s - A n Analysis Base d o n Acddents , Part

s I an d II , Journa

l o f Hazardous Materials , 8 (1984) .



## \\lmP.4 7

APPENDI X A ADDITIONA L INFORMATIO N O N CLASSIFICATIO N SYSTEM S AN D ACCIDEN T HISTORIE S FO R FLAMMABL E CHEMICAL S

\ &-41 - Appendi x A . Additiona

l Information o n Classificatio n System s an d Acdden tHistorie s for Flammabl

e Chemical s
A l Classificatio n System s fo r Flammable Chemical s A.1. 1 Definition s Related t o Classificatio n o f Flammable Substance s A flammable materia

l i s "an y solid , liquid , vapor o r ga s tha twil l ignite easily an

d bur n rapidly. Flammabl e gase s are ignite d ver

y easily , th e flame an

d hea tpropagation rat

e i s s o grea

ta s t o resembl e a

n explosion , especiall y i f

th e ga s i s confined . Flammable gases ar e extremel y dangerous fir

e hazard s an d requir e precisely regulated storage conditions " (Sa x an d Lewis 1987) . Th e flash poin to f

a chemica

l i s "th e temperatur

e a twhic h a liqui d o r volatil e soli d give s of f a vapo r suffiden tt o for

m a n ignitabl e mixtur

e wit h th e ai r nea r th e surfac

e o f th e liqui d o r withi n th e tes tvessel " (NFP A as dte d b

y Sa x an d Lewis 1987) . Ther

e ar e man y differen tmethod s t o measur

e a chemical' s flash poin tExample

s ar e th e Clevelan

d Open Cu

p (COC ) an

d Pensky-Marten

s methods . Mos tflas

h poin t test s pas s a flame jus tabove th e surfac e o f th e materia

l bein g tested . Th e materia l i s heate d slowl y an

d th e flash poin ti s define

d as th e temperatur

e a twhic h th e vapor generated above th e materia l ignites . Not e tha tbecaus e ignitio n i s th e tes ten d point , flash poin ttests ca n b e used as a criterio n for determinin g whethe r a materia

l i s flammable o r no tHas h pointi s als o related t o a chemical' s volatility . Unfortunately , mos tflash poin ttests ar e relativel y inaccurate , particularl

y when applied t o viscou s liquid s (thei r precisio n i s generall y ±3° F (AST

M 1969)) . Th e boilin g poin to f

a chemica

l i s "th e temperatur

e o f a liqui d atwhic

h it s vapor pressur

e i s equa l t o o r ver y slightly greater tha

n th e atmospheric pressur e o f th e environment " (Sa

x an d Lewis 1987) . Boilin g poin ti s a n indicato r o f

a chemical' s volatility . Boilin g poin ttests ar e relatively accurat

e an d simpl e t o run . A.1. 2 DO T Classification s Curren tDO T classifications fo

r flammable materials ar

e as follows (4 9 CF

R 172) : Flammable Liquid : An

y liquid havin

g a flash poin tbelo w 100° F (37.8°C) . Combustibl e Liquid : Liqui d wit h flash poin to f

100° F (37.8°C ) o r greater, an d les s tha n 200° F (93°C) . Flammable Solid : An

y soli d material , othe r tha n a n explosive , whic

h unde r norma l transportatio n condition s i s liabl e t o caus e fires throug h frictio n o r retaine

d heat , o r whic

h ca n b e ignited readil

y an d burn s s o vigorously an

d persistentl

y as t o aeat e a seriou s transportation hazard. Flammable Gas : Compresse d ga s i s define d as a materia

l havin g pressur e greater tha

n 4 0 psi a a

t 70°F , o r pressur

e greate r tha n 10 4 psi a a t130°F , o r a flammable liquid , vapo r pressur e greate r tha n 4 0 psi a a

t100°F ; a compressed ga

s i s classe d as flammabl e if mixtur e o f 13 % o r les s b

y volum e wit

h ai r form s flammable mixtur e o r flammable rang

e i s wider tha

n 12% , o r i ti s show

n t o b e explosiv e o r flammable b

y on e o f severa l tes tprocedures . DO T published a proposed rul e o n Novembe r 6,198 7 t o reclassif

y chemical s consistentwit h Unite d Nation s (UN ) Internationa l standards . Th e proposed flammable classification s are : Hazar d Clas s 2. 1 Gases , ignitabl e whe n i n a mixtur

e o f 1 3 percen

to r les s b y volume wit

h air , o r hav

e a flammable rang

e wit h ai r o f a tleas t1 2 percen

tregardless o f

th e lower flammable limi tA gas i s defined a s a substance wit

h a norma

l boilin g poin to f

20° C (68°F ) o r les s a

ton e atmospher

e pressure . Flammabl e gase s ar e no tassigned t o packin

g groups . 

# H-i -P.4 9

-42 - t * Hazar d Clas s 3 Liquids , wit

h flash point s o f

60.5° C (141°F ) o r

lower

. Packin g group s ar e assigne d accordin g t o flash poin t

an d boilin g poin t Hazar d Qas s 3 Packin g Group s Packin g Grou p I - Boilin g poin t les s tha n 35° C (95°F)

. Packin g Grou p I I - Flas h poin t les s tha n 23° C (73°F ) an d boilin g poin t greate r tha n 35° C (95°F)

. Packin g Grou p m- Flas h poin t betwee n 23° C (73°F ) an d 60.5° C (171°F ) an d boilin g poin t greate r tha n 35° C (95°F)

. A U NFP

A Classification s NFP A ratings fo r

flammability ar e a s follow s (NFP A 1984) : NFP A 4 Assigne d t o material s tha t wil l bur n readil y and'ar e readil y disperse d i n ai r o r wil l vaporiz e rapidly o r

completel y a t

atmospheri c pressur e an d norma l ambien t temperature
. Gase s an d cryogeni c material s ar e included , a s wel l a s liquid s o r liquefie d gase s with flash point s belo w 22.8° C (73°F ) an d boilin g point s belo w 37.8° C (100T)

. NFP A 3 Assigne d t o liquid s an d solid s tha t can b e ignite d unde r

almos t al l ambien t temperatur e conditions

. Liquid s wit h flash point s belo w 22.8° C (73°F ) an d boilin g point s a t o r abov e 37.8° C (100°F) , o r flash point s a t

o r abov e 22.8° C (73°F ) an d belo w 37.8° C (100°F)

. NFP A 2 Assigne d t o material s tha t mus t b e moderatel y heate d o r

expose d t o relativel y hig h ambien t temperature s befor e ignitio n can occur . Woul d no t unde r norma l condition s for mhazardou s atmosphere s with air

. Liquid s wit h flash point s greate r

tha n 37.8° C (100°F ) an d les s tha n o r

equa l t o 93.4° C (200°F)

. NFP A 1 Assigne d t o material s tha t mus t b e preheate d befor e ignitio n can occur . Considerabl e preheatin g require d unde r al l ambien t

temperatur e conditions

. Liquids , solids , an d semi-solid s with flash poin t greate r tha n 93.4° C (200°F)

. NFP A 0 Assigne d t o material s tha t wil l no t burn

. Th e classification s i n NFP A 3 0 are : Flammabl e Liqui d Flas h Poin t < 100° F (37.8°C ) Vapo r Pressur e < 4 0 psi a@ 100° F (37.8°C ) Clas s I A Flas h Poin t < 73° F (22.8°C ) Boilin g Poin t

< 100° F (37.8°C ) Qas s I B Flas h Poin t

< 73° F (22.8°C ) Boilin g Poin t

_ _100° F (37.8°C ) Clas s I C Flas h Poin t > 73° F (22.8°C ) an d < 100° F (37.8°C ) Combustibl e Liqui d Flas h Poin t £ 100° F (37.8°C ) Qas s I I 100° F (37.8°C )

_ _Has h Poin t

< 140° F (60°C ) Qas s III A 140° F (60°C ) < Has h Poin t < 200° F (93°C ) 

# 11 5P.5 0
-43 - f Clas s HI

B Flas h Point> 200° F (93°C ) NFP A 70 4 give s Qas s IA liquid s a flammability rating o f 4 an d Qas s I B an d I C liquid s a flammability ratin g o f 3 . A.L 4 EE C Indicative Criteri a Th e Indicativ

e Criteri a related t o flammability ar e a s follow s (EE C 1982) : Flammable Gases : Substance s whic h i n th e gaseou s state atnorma l pressur e an d mixe d wit h air becom e flammable an

d th e boilin g poin to f

whic h atnorma

l pressur e i s 20° C o r below . Highl y Flammable Substance s whic h hav e a flas h poin tlowe r tha

n 21° C an d th e boilin g poin to f Liquids : whic h atnorma

l pressur e i s above 20° C Flammable Liquids : Substance s whic h hav e a flas h poin tlowe r tha

n 55° C an

d whic h remain liqui d unde r pressure , where particula r processin g conditions , suc h as hig h pressur e an d hig h temperature , ma

y aeat e major-acdden

thazards . A2 OSH A Regulation s for Servic

e Station s Som e o f th e specifi c requirement

s fo r flammable liquid s (e.g. , gasoline ) included i n OSHA' s regulations fo r service station s ar

e th e following :

• Abovegroun

d tank s i n a bul k plantma

y b e conneae d b

y pipin g t o service statio n undergroun

d tank s if a valve i s instaUe

d withi n contro l o f

service statio n personnel ;

• Hammabl e liquid s ca n b e dispersed fro

m tan k vehicle s i n non-publi c area s if th e vehicle , hose , an

d nozzl e meetrequirements ;

• Qas s I (flammable ) liquids cannotb e stored i n a basemen to r pi tunles s there i s ventilation ;

• Electrica

l an d heating equipmen

tmus tmeetcertain standard

s when installe d i n area

s where flammable liquid s ar e store d o r handled ;

• N o smoking o r ope n flames i n area s used fo r fuelin g o r servicing , an

d motor s mustb e shu tof f durin g fueling . A3 Additiona

l Information fro

m th e Acut

e Hazardous Event

s Dat a Bas e Th e Acute Hazardou

s Event s Dat a Bas e (AHE/DB ) include s information o n 77 3 inddent s for whic h on e o f th e en d effect

s (u p t o fou

r end effect

s ma y b e listed ) wa

s fire o r explosion . Mos to f th e explosio n inddent s involved flammable chemicals rather tha n explosive s and , therefore , wer e included i n thi s analysi s o f flammable chemica

l acddents . Th e first(o r primary ) en d effe a wa

s liste d as fir

e o r explosio n i n 54 2 (7 0 percent

) o f suc h inddents ; fo

r mos to f th e others , spil l o r vapo r releas e wa s liste d as th e firs

ten d effect, an d fir e o r explosio n wa

s second . O

f th e 77 3 fire o r explosio n inddents , 65 2 (8 4 percent ) too k plac e a ta fixed location , whil e 12 1 (1 6 percent ) occurre d durin g transportation . A tota l o f 43 1 death s wa

s reporte d resulting from 8 8 o f

th e fir e o r explosio n inddents , an d 4,19 5 injuries wer e reported from 28 6 inddents . Fire an d explosio n inddent s accoun tfor abou

t1 3 percen

to f th e tota l inddent s i n th e AHE/DB , bu tthe y accoun tfor nearl

y 9 2 percen

to f th e death s an

d abou t3 6 percen

to f th e injuries reported . Exhibi

tA- 1 graphicall

y present s fir e an d explosio n event

s an d deaths an

d injuries i n fir

e an d explosio n event

s compare d t o th e tota

l i n th e AHE/DB . 

# \ll

_P.5 1

ExhibitA- 1 FIRE AN D EXPLOSIO N EVENT S COMPARE D T O AL L EVENT S I

N ACUT E HAZARDOU S EVENT S DAT A BAS E 

## Fir e an d Explosio n Event s Compare d t o Tota l Event s

Death s i n Fire an d Explosio n Event s Compare d t o Tota l Death s

Injurie s i n Fir e an d Explosio n Event s Compare d t o Tota l Injurie s



# i n-45 -

Specifi c flammable chemical s tha tth e AHE/D B report

s as havin g bee n involved i n tw

o o r mor e in-plant fire o r explosio n inddent s ar e presente d i n ExhibitA-2 . Numbe r o f inddent s versu

s boilin g poin t(a s a

n indicatio n o f

volatility ) i s shown ; th e DO T hazar d clas s an d packing grou

p tha twould b e assigned based o n flash poin tan

d boilin g poin ti s als o indicate d for eac h chemica

l (se e key) . I

n th e cas e o f

som e fue l chemical s (gasoline , propane , butane , natura l gas/methane ) th e numbe r o f in-plantinddents wa

s estimate d from th e numbe

r reported i n th e 1985 versio n o f th e AHE/DB , as fuel s hav e bee n delete d from th e 198 8 version , b y assumin g tha tth e numbe

r o f inddent s woul d hav

e inaease d b

y a faao r o f

2 . Th e tota l numbe

r o f inddent s i n th e 1988 versio n o f th e dat a bas e wa s approximatel

y doubl e th e numbe

r i n th e 1985 version ; therefore , i twa

s assume d tha tth e numbe

r o f fue l inddents probabl

y als o woul d hav

e approximatel

y doubled . A s ExhibitA- 2 shows , a numbe r o f flammable gase s were reported involved i n in-plan tfires o r explosions , a s wer e severa

l liquid s i n DO T Packin g Group I/NFP A Flammabilit

y Ratin g 4 (Le. , th e mos tflammable an d volatil e categories) . There wer e als o a numbe r o f flammabl e chemical s tha

tfal l into DO T packin

g group s n an

d H I an d severa l chemical s tha

tare considered merel

y combustibl e rather tha

n flammable b

y DO T an d NFP A standards . Ther

e doe s no tappea

r t o b e an y clear correlatio n betwee n physical/chemica

l propertie s (flash poin tan d boilin g point ) an

d th e numbe

r o f fir e an d explosio n inddent

s reported fo r chemical s i n th e AHE/DB . Th e severit y o f th e inddents , a

s indicated b

y th e numbe

r o f death s an

d injuries tha tresulted , wa

s als o considere d i n relatio n t o th e flash point s an d boilin g point

s o f th e chemicals . Ther

e di d no tappea

r t o b e a clear correlatio n betwee n th e properties o f th e chemical s an

d th e severit

y o f th e inddents . Acddent s an

d resultin g consequence s ar e dependentno tonl y upo n th e physical/chemica l propertie s o f

th e chemical s involved , butals o o n faaor s suc h a s location , time , weather, amount, othe r chemical s nearby, an

d releas e conditions ; littl e information o n thes e faaor s i s provide d i n th e AHE/DB . Productio n volum e fo

r th e flammable an

d combustibl e chemical s show n i n Exhibi

tA- 2 wa s considere d as a possibl e faao r related t o th e numbe r o f inddent s reported . Although severa l high-volum

e chemical s were involved i n relatively larg e number s o f in-plantinddents (toluen e i n 1 7 inddents , gasolin e i n a n estimate d 1 3 inddents , viny

l chlorid e i n 7 inddents) , there appear s t o b e n o clear correlatio n betwee n numbe r o f inddent s an

d productio n volume . I n additio n t o th e specifi c chemical s show n i n Exhibi

tA-2 , there wer

e man y unknow n chemical s an

d non specifi c materials involved i n inddent s reported i n th e AHE/DB . A larg e numbe r o f inddents (61 ) involve d unknow

n substances . Chemica

l types o r categorie s liste d includ e th e following : Alcohol : 3 Explosives : 1 4 Fertilizer : 4 Hammable chemicals , gas , liquid , o r material : 7 Hazardou s wast e o r industria

l waste : 1 2 Paint : 7 Pestidde : 2 9 Petroleum product

s o r petroleum refinin

g slurry : 6 Plastics : 7 Rubber, rubbe

r hos e o r tires : 8 Solvents : 1 3 Variou s othe r non-specifi c listing s als o ar e included , suc

h a s severa l kind s o f oi l an d fuel , an d non chemica l materials suc

h as insulate d wire . A numbe r o f chemical s reported t o hav e bee n involved i n fire

s o r explosion s ar

e notflammable o r ar

e onl y slightly flammable (e.g. , chlorin e (2 3 inddents) , ammoni a (1 9 inddents) , hydrochloric ad d (1 2 inddents) , nitri c ad d (1 1 inddents)) . Thes e chemical s wer e no tincluded i n Exhibi

t2 ; thei r involvemen

ti n fires an

d explosion s ma

y b e relate d t o thei r reactivitie s an d othe r chemical s involved i n th e inddents rathe r tha n t o flammability .


# u aExhibitA- 2 FLAMMABL

E GASES AN D LIQUID S REPORTED I

N IN-PLANT FIRE S OR EXPLOSION S

2 0

c V • o

• J — o

_ c c o ' n Q a. X UJ \ I ) L . I I L . U JD 

### E

_ } 

## z 1 9 -

1 8 - 1 7 - 1 6 - 1 5 1 4 - 1 3 - 1 2 - 1 1 1 0 H 9 8 - 7 - 6 - 5 4 - 3 - 2 - 1 - 0 TOLUEN E 

## o

GASOLIN E O

PROPAN E D

HYOR06E N D *

ETHYLEN E D HY0R06E N

SULFID E 

# • METHAN E P SHAN E ACETYLEN E

P P PHOSPHIN E D VINY L CHLORID E

D BUTAN E 

## a ETHYLEN E 0X10 E P ISOBUTAN E P HYDROGE

N CYANIO C O O ETHYL ETHE R a.b.e. d 

### ++ • o «*» < o Mttanti c HEXM E "TMJ L KTHY I ipm .

BUTADIEN E 

## a CARR M OISULFI K

KROLEI N ACETON E STYREN E

A XYLEN E 

## o KEROSEN E 

## o NAPHTH A

*'" 1 ^ ^. r KTHKt*U KACNYUY E O A A tTlf, L MRPHOLIN E ACETAT E TM rnuL, " t CREOSOT E

A

NITROBENZEN

E X X X OIKTHY l TOLUEN E SULFOXID E OIISOCYANAT E
-30 0 1 -10 0 0 

### 10 0 30 0

mS> \ I Boilin g Poin t (degree s C ) • VINY L ACETAT E bTRICHLOROETHAN E c BENZEN E d TRICHLOROETHYLEN E

Ic oP.5 4

-47 - KE Y FO R EXHIBI T A- 2
O Flammable gase s (Boilin g poin t<.20°C ) DO T Hazar

d Qas s 2. 1 (2 3 for flammable an d poison ) NFP A Flammabilit

y Ratin g 4

+ Flammable liquids , DO T Packing Grou p I o r equivalent DO T Hazar

d Qas s 3 , Packin

g Grou p I : Boilin g poin t<35° C NFP A Flammabilit

y Ratin g 4 : Boilin g poin t<38°C , Flas h poin t<23° C

° Flammabl e liquids , DO T Packin g Grou p I I o r equivalen

t DO T Hazar

d Qas s 3 , Packin

g Grou p II : Boilin g poin t>35°C , Flas h poin t<23° C NFPA Flammabilit

y Ratin g 3 : Boilin g poin t>38°C , Flas h poin t<23°C , o r Flas h poin t<38° C an

d Flas h poin t>23° C A Flammable liquids , DO T Packin g Grou p H I o r equivalent DO T Hazar

d Qas s 3 , Packin

g Grou p HI : Boilin g poin t>35°C , Flash poin t>23°C , Flas h poin t<60.5° C NFP A Flammabilit

y Ratin g 2 : Flash poin t>38°C , Flash poin t<93° C X Combustible liquid s N o applicabl e DO T Hazar d Qas s NFP A Flammabilit

y Ratin g 2 o r 1 (NFPA 1 : Flash poin t>93°C )



# I 

# ID -P.5 5

APPENDI X B METHODOLOGIE S FO R MODELLIN G

\%\P.5 6
-49 -

B. 1 WHAZA

N (Worl d Bank Hazar

d Analysis ) B.1. 1 Genera

l Descriptio n WHAZA N consist

s o f a serie s o f

1 3 consequenc e model s (alon g wit h a database o f

chemica l propertie s for a selectio n o f

importan thazardous chemicals ) whic h ca n b e ru n individuall

y o r linked together . Th e consequenc e model s consis to f 4 release/evaporatio n models , 5 dispersio n models , an d 4 model s dealin g wit h fires an d explosions . Fo r thi s analysis , th e linke d model for instantaneou s an d prolonge d release s wa

s used . Thi s mode l produce s outputs whic h indud e poo l fires,

je tfires, vapo r dou d explosions , fireballs/BLEVEs, evaporatio n rate s for pools , an d flashe d fraction s for liquified gases . Th e evaporatio n rate wa s inpu tint o th e individua l (stand-alone ) vapo r dou d dispersio n model t o determin e th e maximu m distance t o 5 0 percento f

th e LFL . Similarly , flashe d fraction wa

s inpu tinto th e vapo r dou d explosio n stand-alon e mode l t o determin e distance s fo r vapo r clou d explosion s o f liquified gases . Th e equation s use d i n thi s repor

tar e described below . Th e model s ca n b e ru n o n a n IB M P C an d mos tlikel y o n othe r compatibl e systems .
B.L 2 WHAZA

N Pressurize d Releas e Outflo w Fo r liqui d store d i n a refrigerate d o r pressurized container , WHAZA N calculate s liqui d outflo w usin g th e Bernoull i equation . Th e equatio n assumes th e drivin g force for outflo w ma

y b e th e liqui d head o r difference betwee n th e storag e pressur e an d th e atmospheri c pressure . W = CDARDLPITVP^/D L + 2gH] % where : W = releas e rat

e (kg/sec ) C Q = coeffiden to f

discharg e A% = are a o f releas e (m 2 ) D L = densit

y o f th e liqui d (kg/m 3 ) P j = initial (storage ) pressur e (N/m 2 ) P A = atmospheri c pressur e (N/m 2 ) g = gravitationa

l acceleratio n (m/s 2 ) H = liqui d head (m ) Th e fraction o f

liqui d tha

tflashes onc e th e fluid ha s reache d atmospheric pressur

e i s given by :
F v = CPLCT I - T^/H ^ where : F v = fraction flashed t o vapo r Cp L = liqui d specifi c hea t(J/kg/K ) T-. = storag e temperatur e (K) T B = boilin g poin t(K ) Hya- s heato f

evaporatio n (J/kg

)

B.L 3 WHAZA

N Two-Phas e Outflo

w Fo r a two-phas e outflo w (liqui d an d gas ) o f a flashin g liquid , th e releas e rat

e o f th e liqui d i s give

n by : W = ARC Q (2D m (P s -P c )) , A 

# 19 &-50

-

where : D m= density o f

two-phas e mixtur e (kg/m 3 ) P g = saturate d pressur e (N/rn 2 ) P c - = choke d pressur e (N/m 2 ) Th e densit

y o f th e 2-phas e mixtur e a t

th e exi t plan e i s given by : D m= l/(TyD v ) + (l-F v )(D- j where : D v = density o f

th e vapo r

(kg/m 3 ) Th e fraction o f

th e releas e tha t

ha s flashed t o vapo r

a t th e exi t plane , F v i s give n by : F y = CpLCTi-T^/H^ p where : Cp L = Liqui d specifi c hea t (J/kg/K) T s = Saturatio n Temperatur e (K )

B.1. 4 WHAZA

N Ga s Outflo w Thes e equation s ma

y b e applie d t o th e discharg e o f toxi c an d flammable gase s fromlarg e vessel s o r pipes

. Thi s mode l assume s reversibl e adiabati c expansio n an d idea l ga s behavior

. T o calculat e ga s outflo w rates , WHAZA N use s th e following : W = YC D A R Pi[MG(2/(G+l))( G+1 > / ( G

- 1 )/RTl 1/ 2 wher e W = ga s outflo w (kg/fc ) Y = coefficient

i n ga s outflo w mode l C Q = coeffiden t

o f discharg e A R= are ao f

releas e (m 2 ) P a= initia l (storage) pressur e (N/m 2 ) M = molecular

weigh t G = rati o o f

vapo r specifi c heat s a t

constan t volum e an d a t

constan t pressur e R = universa l ga s constan t (Nm/K-mole ) T = temperatur e (K ) I n mos t case s o f interest , flow wil l b e critica l becaus e upstrea mpressur e exceeds :

P A (2/(G+1))( G/1

- G >

I n thes e case s Y = 1.0

. I n th e even t tha t th e upstrea mpressur e i s les s tha n tha t give n b y th e abov e expression , then : Y = (P A /P 1 ) 1/G [1-(P A /P 1 )( G

- 1 ) /G ] 1/2 [2((G+1)/2)( G+1 ) / ( G1 >/(G-1)] 1/ 2 

# \lZ>P.5 8

-51 -

, B.L 5 WHAZA

N Adiabati c Expansio n Outflo w Thes e equation s describ e th e initial behavio r o f a n instantaneou s pressurized release . Th e outflo w ma y b e use d fo r subsequen

tdispersio n calculations . Th e model assume s a cor e o f unifor m concentratio n containin g 50 % o f

th e release d mass surrounde d b y a periphera

l zon e charaaerize d b

y a Gaussia

n distributio n o f

concentration . Fo r th e estimatio n o f th e rapi d adiabati c expansion experienced durin g th e instantaneou s releas e o f

a flashing liqui d o r pressurize d vapor , WHAZA N use s a simpl e two zon e hemispherica

l mode L Th e expansio n proces s i s considere d t o hav e two stages : (1 ) I n th e firststage , gas expand s dow n t o atmospheri c pressur

e o r liqui d flashes (as appropriate) . Th e change i n interna

l energ y is : Uj-U^C/iyTz ) Th e energ y o f expansio n is : 

### E = C^-T ^ -PAO^ ) where V*. = Initia l interna l energ y (J/kg ) U 2 = final interna l energ y (J/kg ) C y = vapor specifi c hea tatconstan

tvolum e (J/kg/K

) T j = storag e temperatur e (K ) T 2 = temperatur

e afte r initia l expansion (k ) E = energ

y o f expansion (J ) P A = atmospheri c pressur e (N/m 2 ) V j = initia

l volum e (m 3 ) V 2 = final volum e (m 3 ) (2 ) I n th e secon d stage , th e kineti c energ y develope d b

y th e initial expansion drives th e turbulen t mixin g o f air into th e clou d a

s th e clou d spread

s outward . Onc e th e expansion energy , E , ha s bee n determined , th e expressio n fo r th e turbulen

tcoeffiden tis : Kj , = 0.0137E 1/2 V GO 1/3 [tE % /V GO 1/3 ]- 1/ 4

an d th e expressio n for th e cor e radiu s a s a function o f

tim e is :

r c = 136(4K D t) ^ wher e K D = turbulen

tdiffusion coeffiden t(m 2 /sec ) E = expansio n energ y (J ) V G O = volum e o f

a uni tga s a tstandar d condition s (kg/m 3 ) t= tim e (sec ) r c = radius o f

clou d core (m ) Th e equatio n fo

r th e concentratio n i n th e core is : j c= 0.0478V GO

/((4K D t) 3 > 2 ) 

# ykP.5 9


### -52

- Th e followin

g ar e expression s fo

r th e cor e concentratio n an

d radiu s at th e en d o f th e mixing : j c 

### = 172.95E-°- 9



### pp m
r c 

### = 0.08837E°* 3 

### V GO W



### I t wa s foun d (Ulde n 1974 ) tha t th e end of

th e initia l expansio n occurred a

t adou d radius, r , suc

h tha t r/r c 

### = 1.456

. A

t thi s valu e o

f r/r ^ 91 % p

f th e release d materia

l i s stil l withi

n th e doud

. B.1. 6 WHAZA

N Evaporatio

n fro m liqui d Poo

l Fo r a n instantaneou s spill , i

f th e atmospheri c temperatur e i s les s tha

n th e norma

l boilin g point o f th e liquid , evaporatio n i s calculated by :

d* 1 *

_a(P-W/j? r ) £7<2-»>/(a*n) r (4*n)/<2*j> )



### wher e d m d t = chang e o

f mas s wit h tim e (kg/sec) P s 

### = saturate d pressur e (N/m

2

### ) M = molecula

r weigh t R = universa

l ga s constan t (Nm/K-mole

) T A 

### = atmospheri c temperatur e (K ) U = win

d spee d (m/s )

= radius o

f poo l (m )

= 4.785xl0" 3 

### neutra

l atmospheri c stabilit

y = 0.2 5 (th e midpoin

t o f th e observe

d range ) r

I f th e atmospheri c temperatur e > norma

l boilin g poin t o f th e chemical , tw

o alternativ e model s apply

. I f th e dominan

t mean s o f transfe r o f hea t t o th e poo l i s wind , th e previou s equatio n i s appropriate

. I f th e dominan

t hea t transfe r mechanismi s conduction through th e ground , th e appropriat e mode l i s a s follows :

dm = nr 2 

### K(T.-T

B 

### ) I (H^t*'

2 

### )

wher e K = 6.68x10 s 

### t o represen

t a n average soil
B.1. 7 WHAZA

N Poo l Fire s T o describ e apoo l fire phenomenon , WHAZA N use s equation s governin

g poo l sprea

d an d burnin g rate
. I n poo l spread , th e liquid i s assume d t o for madrcula

r poo l o f unifor mheight

. Fo

r a n instantaneou s spill , th e poo l radiu s i s give n by : 

# T 5P.6 0

-53 -

. r = (t//3) % where : 0 = (irD L

/ 8 gm) * where : D L = densit

y o f liqui d (kg/m 3 ) g = gravitationa

l acceleratio n = 9. 8 m/s 2

m = release d mass i n cloud/poo l (kg ) Fo r continuou s spills :

r = (t/fl * where : 0 = (97rD L

/32gW) 1/

3 T o calculat

e burnin g rate for liquid s havin

g boilin g points abov

e ambien ttemperature :
d m 0.00 1 H, c dt IC

PL {T B -T K ) +fl v v ]

where : H c = hea

to f combustio n (J/kg

) Cp L = liqui d specifi c hea t(J/kg/K ) Hya p = hea to f evaporation (J/kg

) T B = boilin g poin t(k ) T A = atmospheri c temperatur e (K) dm/d t= poo l sprea

d Fo r liquid s having boilin g point s belo w ambien

ttemperature :

dm 0.001H C dt = Hyp

Th e hea trelease d i s calculated as :

(itr 2 + 2nrfl ) (-^)nH c (7 2 (45) 0 * 6 1 + 1 ) ef t 

# \7J oP.6 1


### -54

-

where :
r = radius o

f poo l (m ) Th e effidenc

y faao r n ha s been show

n b y test s t o have avalu e u p t o aroun d 035

. Th e flam e heigh t i s calculate

d as :

i f

= 8 4 r ( — )

1 dt' D. (2gr)V* 0.6 1



### where : g = gravitationa

l acceleration (m/s 2



### ) Numeric input

datarequirement s fo

r th e "instantaneous " cas e are a s follows : Paramete r Vali d Rang e Defaul t Spil l siz e 1 0 - 10 7 

### k g Bun d are a0 - 10 6 

### m 2 

### 0 .Ambien t temperatur

e 20

0 - 400°K 68° F Effidenc y faao r 0.0 1 - 1 0.3 5 Fo r th e continuou s case , th e spil l siz e i s replace d b y th e spil l rate an d duration

. B.L 8 WHAZA

N Je t Fire s The flame lengt

h i s give n by : L = 18. 5 W 04 1 

### where : W = releas e rate (kg/s ) L = lengt h (m ) .Alternativel

y th e flam e lengt h ca n b e base d o n th e distanc e t o th e lowe r flammability limi

t (LFL) a s give

n b y th e je t dispersion model

. T o calculat e je t dispersion , th e envelop e withi n whic h th e concentratio n o

f a turbulen t je t i s abov e aspecifie d level , j c 

### , i s represente d b

y amajo r axi s o f length :

A = <2> 1+ jb 2 ) *>Jc * A- a - i DjD^ 2

/(0.220^)



### an d amino r axi s o f length : 

## xim-rP.6 2

-55 -

B = A-{l/b 2

) log ,

Th e shap e parameter

s ar e given b y b j = 50 3 + 482 DT O - 9.9SD^ b 2 = 23. 0 + 41. 0 DT O where : Dy g = gas densit

y relativ e t o ai r a tth e same conditions , D v l = ga

s densit y afte r initial expansion (relative t o air a tambien tconditions) , j c= specified leve l o f a turbulen

tje t- th e envelop e o f

concentrations o f

a turbulen

tje ti s abov e thi s leve l (ppm) , D : = diameter o f

je tonc e expande

d t o atmospheric pressur

e (m) .
Th e je tshap e i s symmetrica l aboutth e majo

r axis . D : i s calculated assumin g adiabatic expansion . B.1. 9 WHAZA

N Vapo r Cloud Explosions (based o n Buoyan tPlum e Dispersion ) WHAZA N mode

l expresses vapo r clou d explosions i n term s o f overpressur

e versus distance . Overpressurization i s related t o th e dispersio n concentratio n o f th e ga s an d assumption

s abou tit s explosiv e yield . WHAZA N use s th e standar d Gaussia n mode l o f plume dispersion t o calculat e th e ground-level concentratio n o f a buoyan treleas e (wher

e th e releas e poin tca

n b e a tground-leve

l o r at height , h) :

C = W ex p ( -y 2 h 2 \ 

### [2o y 2 

### 20/ J (UOyO,)

where : W = releas e rate (kg/sec ) Y = crosswin

d distance (m ) h = releas e heigh t(m ) U = win d spee d (m/sec ) o y o z = standar

d deviatio n o f

plum e concentratio n profil e The n WHAZA N use s result s o f studie s b y Lees t o relat

e th e explosiv e yiel d o f

th e ga s concentratio n wit

h th e overpressurization wave s distributed over distances . B.1.1 0 WHAZA

N Fireballs/BLEVEs WHAZA N use s empirica l correlation s t o calculat

e th e size , duration , an

d radiantintensit

y o f fireballs o f flammabl e liquid and/or vapor .



### •7 &P.6 3

-56 - Th e maximu

m fireball radius i s give n b y thi s model as :

r m = 2.66 5 m* 32

7 where :

' m = release d mas

s i n clou d (kg )

an d th e duration by . t= 1.089 nr 32 7 Th e energ y release d b

y combustio n ateffidency i s Q = Hf-m

n where : H c = heato f

combustio n (J/kg) n = effidenc

y o f combustio n where n i s foun

d t o var y wit h th e saturate

d vapo r pressur

e o f th e materia

l stored , as

n = 0.27 P s 3 2 where : P s = saturate

d pressur e (MN/m2 ) Th e heatflux a

ta give n distance from th e fireball cente r i s calculated assumin g a n invers e square-la

w relationship .



# .•v *P.6 4

B. 2 ARCHI

E (Automate

d Resourc e fo r Chemica

l Hazar d Indden tEvaluation) B.2. 1 Genera

l Descriptio n I n a combine d effort , FEMA , U.S . DOT , an d U.S . EPA sponsore d th e developmen to f a handboo k an

d compute r progra

m entitle d ARCHIE t o provide emergenc y planning personne

l wit h th e tool s necessar

y t o evaluat e th e natur

e an d magnitude o f

chemica l releas e threat

s fro m potentially hazardou

s facilities . A cor e par

to f th e progra

m estimate s th e downwin d dispersio n o f

a chemica

l releas e given a diversit

y o f releas e scenarios . Th e progra m operate s o n a n IB

M persona

l computer o r othe r compatibl e system . ARCHI E i s capabl e o f

addressing a wid e variet

y o f common acdden tscenarios . Th e scenario s includ e nin e method s t o estimat

e discharg e rat e an d duration o f

a ga s o r liquid releas e from a tan k o r pipeline , seve n method s t o estimate siz e o f th e liquid pool , two method s t o estimat e th e rate a

twhic h a liqui d poo l wil l evaporat

e o r boil , seve n method s dealing wit h explosion s an

d fires, an d on e metho d t o estimate downwin d chemica

l concentration s an

d hazar d zones . ARCHI E finds th e downwin d lengt h o f th e hazar d zon e atth e discharg

e heighto f

th e vapor , th e pea

k concentratio n expeae d atgroun d level , an

d th e lengt

h o f th e hazar d zon e a tgroun d level . Th e vapo r dispersio n model contain s a finite duration equatio n validated b y Palazz i using th e experimenta

l dat a o f D e Raven . Th e mode l use s Pasquill-Giffor d dispersio n coeffidents . B22 ARCHI

E Pressurize d liqui d Releas e Th e releas e scenari o consist s o f pressurize

d liquid releas e from a spherica l tan k wit h a 15 foo tdiameter . Fo r a give n liqui d heigh tan d vapo r space pressure , th e instantaneous liqui d releas e rate from a tan k i s give n b y th e equation :

m= A h C d jo* \.2g Pl

[H L - H h ) + 2 [P 0- P a ) J

where :
m = Discharge rat e (kg/s ) g = Gravitationa

l constan t= 9. 8 m/s 2 p. = Liquid densit

y (kg/m3 ) P 0 = Storag e pressur

e (N/m 2 ) P a = Ambientpressur

e (N/m 2 ) H L = Liquid heightabov e botto m o f containe r (m ) H h = Heigh to f

discharg e openin g (m ) Aj , = Area o f

discharg e openin g (m 2 ) C d = Discharge coeffiden t Thi s assume s th e tan

k i s full . A n averag

e releas e rat

e for th e tan

k ma y b e obtaine d b

y computin g th e tim e (T e ) require

d t o empt y a tank. For a spherica

l tank :

T e = 1 6 Z),. 2 5

T 1 5 D 2 fig C

d 

# \1PP.6 5

-58 - where : D T = Tan k diamete r (m ) D Q = Openin g diamete r (m ) T e = Tim e t o empt y (sec ) B23 ARCHI E Estimatin g Poo l Siz e ARCHI E estimate s poo l siz e fo r instantaneou s release s o f boilin g liquid s i n absenc e o f frictiona l resistanc e durin g spreading . Th e liqui d poo l i s assume d t o b e circula r an d th e poo l i s no tbounde d b y secondar y containmen tTh e maximu m diamete r o f th e poo l is :

1.776 6 

### V-A 

### E 2 1/ 8

where : --'ma

x = maximu m diameter o f poo l (m ) V = tota l liqui d volum e (m 3 ) A = effectiv e gravit

y (sam e a s gravitationa l constan t(g ) fo r spill s o n land ) (m/s 2 ) E y = vaporizatio n flux (kg/m 2 /s ) Th e tim e neede d t o reac h maximu m diameter , t^- p i s calculate d a s follows :

t___ . = 0.696 6

B.2. 4 ARCHI E Volatilizatio n o f liqui d Poo l A_?

„

ARCHI E assume s th e volatil e liqui d i s nea r ambien ttemperatur e whe n discharged . Evaporativ e flux o f volatil e liquid s a s develope d b y U.S . Ai r Forc e Engineerin g an d Service s Laborator y is :

E v = 4.66xl0-«a v 0

- 7 5 T *l° M " P8h

where : Ey = Evaporatio n flux (lbs/min/ft 2 ) U w = Win d spee d (m/h ) P s = Vapo r pressur e o f chemical (m m Hg ) P s h = Vapo r pressur e o f hydrazin e (m m Hg ) My, = Molecula r weigh to f chemica l T F = Spil l temperatur e correctio n faao r 

# \3 (P.6 6


### -59

- Th e spill temperatur

e correctio n faao r

i s define d a s follows : T F 

### =1T<0» C 2 

### T F

### = 1 + A3 x HTT

p T p 

### > 0° C wher e T p 

### i s th e poo l temperatur e in degree s C The vapo

r pressur e o f hydrazin e i s give n b y th e followin

g equation :
ln(P ) = 65.331 9 - 724 

### ^ ' 2 

### - 8.221n(T ) + 6.1557XlO* * T

wher e T i s i n kelvin s an

d P i s i n atmospheres

. Overal l volatilizatio n rate : V w 

### = E y • A wher e A = poo l are a(m 2 

### ) V w 

### = volatilizatio n rate (kg/s ) E y ---vaporizatio n flux (kg/m 2 

### /s ) B.2. 5 ARCHI

E Gas Discharg e fro

mPressurize d Vesse

l Fo r ga s discharg e frompressurized vesse l unde r non-chok e flow conditions , th e mas s flow rat e i s calculated from: 

# -4-iMter-teri r

Unde r choke d flow conditions , th e mas s flow rate i s calculate d from:


### /

_____

y

where : m= Discharg e rate (kg/s ) A b 

### = Openin

g are a(m

2 

### ) 7 = Rati o o

f specifi c heat s p 0 

### = Tan k pressur e (Pascals ) p 2 

### = Ambien

t pressur e (Pascals ) p Q 

### = Densit

y (kg/m

3 

### ) 

# ["himP.6 7


### -60 - Thi s equatio n ignore s deaease s i n discharg e rat e du e t o thermodynami c cooling . Also , thi s equatio n assume s th e discharg e i s adiabati c an d tha tth e wal l friction effect s ar e negligible . B.2. 6 ARCHI E Vapo r Qou d Fir e Mode l Th e lengt h an d widt h dimension s o f a dou d o r plum e o f

flammabl e vapo r i s determine d b y ARCHIE' S mode l o f toxi c vapo r dispersion . Eithe r a neutrall y buoyan to r heav y ga s mode l coul d b e use d t o predi a clou d dimensions . Fo r neutrall y buoyan tgases , ARCHI E consider s release s a s poin tsource s a tgroun d leve l Th e emissio n rate i s constan tAmbien ttemperatur e wa s assume d t o b e 20° C Th e mode l assume s stead y stat e unles s th e releas e duratio n i s significantl y smalle r tha n th e charaaeristi c trave l time . Relativel y short-duratio n release s wer e assume d t o b e instantaneous . ARCHI E use s th e finite duratio n mode l validate d b y Palazz i t o predi a ga s dispersion . Accordin g t o th e model , th e finite concentratio n (Cf ) a tan y locatio n i s give n by :

*£ Lrf( 2L- ) -erf

{ X 

### ~ U 

### f ) 1 when f . t x 

### 2 [ ((2)V*o x



### ) ({2)^ 2 

### o x



### j\ 

# *-§ * erf

f-^^ ) -erf

( X 

## ~^ ) 1 when t

* t K 

### ( (2)^0 , j

((2)i'

2 

### o x 

### )\ *

where : C c 

### = centerlin e concentratio n give n as :

^

_

> 2oy 

### ' c 

### 2no

y 

### o x 

### U w 

### e 2 

### °y x ex p - -

J -j— + ex p - —-?— 2o 2 

### * 2o 2



### Here , t R

### i s th e duratio n o f

releas e i n seconds . Th e maximu m concentratio n i s give n b y th e followin g equation :

(•ma x r* 

# H^M^)]" ^

« u -- ^ M-^&r- U » " ^

(2 3P.6 8

-61 - Th e parameter

s use d i n th e abov e equation s ar e define d as follows : Cgg x = Maximu

m centerlin e concentratio n (kg/m 3 ) Q = Continuou s source releas e rat e (kg/sec ) U w = Wind spee d (m/sec ) z = Vertica

l distance (m ) y = Crosswin

d distance (m ) x = Downwind distanc e (m ) H = Source heigh t(m ) a - = Longitudina

l standar d deviatio n (m ) o y = Latera

l standar d deviatio n (m ) a z - s Vertica

l standar d deviatio n (m ) Th e dispersio n distance s for neutrall y buoyan tgase s are generall

y 2 t o 5 time s larger tha

n thos e for heav

y gases . B.2. 7 ARCHI

E Unconfine

d Vapor Cloud Explosio n ARCHIE use s th e TNT-equivalen tmode l for us e i n evaluating th e vapor clou d explosio n scenario . Th e amoun to f combustio n energ

y i n th e clou d i s compare d wit h th e equivalen

tamoun to f TNT . Considering tha tonl y a fraction o f

th e energ

y i n th e clou d wil l contribut e t o th e explosio n an

d referrin g t o th e TN T explosion/overpressurizatio n data , enable s th e model t o calculat e th e pressurization atdistances from th e explosion . Th e fraction o f energ y i n th e clou d assume

d t o contribut

e t o th e explosio n ranges from 2 t o 2 0 percen tOthe r assumptions include :

• Ambienttemperatur e i s 20°C ; • Effect

s o f terrain , buildings , obstacle s hav e no tbee n considered . Th e equatio n i s state d as :

% r AH. 115 5 •"clou d x - - - - X

Yi

where :

m TN T = TN T equivalentmas

s (lbs ) AH C = Lowe r heato f combustio n (kcal/kg ) m ciou d = Mass m dou d (lbs ) Y f = Yiel d faao r Distanc e t o a give n overpressurization i s the n calculate d from th e equation :

X = m^ 3 ex p (3.503 1 - 0.724 1 l n (O p ) + 0.039 8 (lnO p ) 2 )

where : X = distanc e t o given overpressur e (ft) O p = Pea k overpressur

e (psi ) 

# \7A>

### -62

-

. B.2. 8 ARCHI E Tan k Overpressurizatio

n Explosio n Mode l Thi s mode l assume s tha tth e pressurizatio

n wave s aeate d b

y a n explodin g tan k wil l propagat e omnidirectionall

y i n a hiemispherica

l field a tgroun d level . Th

e computationa

l algorith m proceed s a s follows : 1 . Calculat

e th e rati o Pj/P a 

### wher e Pa 

### i s th e absolut e ambien tpressur e an d P j i s the absolut

e interna l ga s pressur e a twhic h th e tan k i s expeaed t

o rupture . 2 . Comput

e th e ratio T/T a 

### wher

e T a 

### i s th e absolut e ambien tai r temperatur

e an d T j i s th e absolut e temperatur

e o f th e ga s in th e tank . 3 . Determin

e th e initia l overpressur

e ratio, P ^ b

y solvin g th e following equatio

n b y tria l an d error .

f = o in(^ )

P " ln( l + P, 0 )

- 2 Y i l n 1-Y i .-* , l-(Yi-DP T O

^fVY- 3 + 0.5 Y a (Y a + D P eo



### wher e . 7 i s th e rati o o f specifi c hea t a t constan t pressur e t o tha t a t constan t volume

. 4

. Comput

e th e nondimensiona

l startin g distanc e R 0 

### from: 

# lU H ti - 1 1/ 3



### Comput e th e value o

f R from: 

# ftd"

Y i " 1



### where : V -

= Volum e o f th e ga s i n th e tan

k (ft 3 

### ) r = Distanc e fromth e cente r o f th e tan k a t whic h th e side-on overpressur

e i s desired (ft

) 6

. Locat

e th e point

assodate d wit

h P ^ an d R 0 

### o n a n overpressurization graph

. 7

. Follo

w th e neares t

curv e fo r P s 

### vs . R t o th e R value compute d i n ste p 5

. Rea d th e P s 

### value assodate d wit

h thi s R value

. I

f th e ga s vesse l i s o n th e groun

d and/o r clos e t o areflectin

g surface , inaeas e P s 

### b

y 100% fo r R les s tha n 1 an d b y 10% fo r R greate r tha n 1

. 

# \"b5P.7 0
-63 - 8 . Th e side-o n overpressur e i s determine

d b y multiplying th e above resultan tvalu e o f P s b y th e absolut e valu e ambien

tatmospheri c pressur

e P a . B_2. 9 ARCHI E Fireball Mode

l I n calculatin g th e maximu m diamete r an

d heightth e fireball attains , a s wel l a s th e saf e separatio n distance s for fatalit

y an d injury, ARCHIE make

s th e followin g assumptions : Fue l i s propane Ambienttemperatur

e i s 20° C Atmospheri c absorptio n o f therma l radiation i s negligibl e Fractio n o f

combustio n energ

y radiated = 0. 2 Observe r i s atgroun

d level Minimu m fatalit y zon e i s equa

l t o half th e maximu

m diamete r calculated Based o n a serie s o f

experiments : D__a x = 1CT J Z = 26.3W 1/

3 

### n T = 2.23W 1A

5 where : W = Mass i n vesse l (lbs ) Djug - = Maximu

m diameter o f

fireball (ft

) Z = Maximu

m heighto f

firebal l (ft ) T = Duratio n o f

firebal l (s ) Th e saf e separatio n distance fo

r fatality , XF , i n feet , wa

s foun d t o be : X F = 1.48W

0

- 5 6 W > 200 0 lb s X F = 8.0W

0 * 3 3 W < 200 0 lb s
Fo r injury, th e saf

e separatio n distance , XI , i n feet , is : X I = 4.53W 0

- 5 2

B.2.1 0 ARCHI

E liqui d Pool Fire Mode

l ARCHI E calculate s various poo l fire faaor s t o determine th e radiu s i n whic h injurie s an d fatalitie s ar

e expeae d from th e fire . Thes e faaor s includ e burnin g velodty , maximu

m poo l diameter , flame height , effective emissiv e power , indden tflux, an d vie w faao r (fraction o f

flame see n b

y a give n observer) . I

n calculatin g thes e faaors , there ar e severa l simplifyin

g assumptions :

• Poo l are

a i s circula

r • Observe

r i s atgroun

d leve l

• Ambien

ttemperatur

e i s 20° C

• Atmospheri c absorptio n o f therma l radiation i s negligibl e • Negligibl e win

d i n th e vicinit

y o f th e flame; thus , unifor

m therma l radiation field radiall

y an d n o flame til t

• Poo l ignite s shortl

y afte r releas e • Burnin

g rat e equal s spil l rate Th e scenari o chose n t o mode l i s a n instantaneous Uqui d hydrocarbo

n releas e i n th e absence o f friaiona l resistance durin

g spreading . Th e equatio n t o estimat e th e burnin

g velodt y is : 

# lit .P.7 1

-64

-

92.6e- 0

- 0043r 'Aff . IP' 7

P 6

where : y « = Burnin g velodt y (m/s ) M W = Molecula

r weight (kg/kmol ) p = Liqui d specifi c gravit y T B = Norma l boilin g poin t (°F ) I n th e poo l fire scenario , th e radiu s o f th e poo l inaease s unti l al l th e materia l i s consume d b y th e fire. Th e maximu mdiamete r

an d tim e t o reac h maximu mdiamete r ar e given by

.

= 1.776 6 V 3 A 1/ 8

t W = 0.696 6 Ay 2 i / «

where : V = Tota l liqui d volum e (m 3 ) y = Burnin g velodt y (m/s ) A = Effeaiv e gravit

y (sam e a s gravitationa l constan t (g ) for spill s o n land ) (m/fc 2 ) Th e tim e average d poo l diamete r i s obtaine d b y dividin g th e maximumdiamete r b y th e squar e roo t

o f two
. Th e mea n visibl e flame heigh t i s base d o n equation s correlate d wit h dat afromlaboratory fires

. Visibl e flame height , H flame , i s expresse d as :

Bfum = "D , •BV p Pa*/£ ^ 0.6 1

where :

H nam e = Flam e -^-g 1 " (TM) p = Liqui d densit

y (kg/m 3 ) p a = Ai r densit y a t ambien t temperatur e (kg/m3 ) D p = Poo l diamete r

(m ) g = Gravitationa l acceleratio n - = 9. 8 m/s 2 Effectiv e emissiv e power

o f th e flam e account s for

th e indden t

flu x shieldin g b

y surroundin g layer s o f smok e fo r liqui d hydrocarbo n fires

. Base d o n literatur e dat aan d correlate d t o th e norma l boilin g point , effectiv e emissiv e power

i s define d as : 

# IX )P.7 2

-65 -

, E p = -031 3 T B + 11 7 where : E p = Effectiv e emissiv e power (kW/m 2 ) T B = Norma

l boilin g poin t(°F ) Th e indden tflux atan

y give n locatio n i s given b

y th e equation : Qincident-EpXrxV F where : ^inciden t= Indden tflux (*W/m 2 ) T = Transmissivit

y V F = Geometri c vie w faao r r , th e transmissivit

y coeffiden ti s mainl

y a functio n o f

th e path-lengt

h (distance from observe r t o flame surface) , relativ e humidity , an d th e flame temperature . Fo r th e calculatio n schem e i n ARCHIE , r ha s bee n se tt o 1 , an

d th e attenuatio n o f

therma l flux du e t o atmospheric absorptio n i s no ttake n int o accoun t Thi s assumption provides a conservativ e hazar d estimate , sinc e th e presence o f water an d carbon dioxid e tend s t o reduc

e th e indden tflux atan

y give n location . Th e vie w faao r defines th e fraction o f flam e tha ti s see n b

y a give n observer. Thi s geometri c ter m ha s bee n calculate d as a function o f distance from th e flame cente r fo r a n uprigh tflame approximate

d b y a cylinder . I

tha s als o bee n assume

d tha tth e optimu

m orientatio n betwee n observer an d flame tha

tyield s a maximu m vie w faao r prevails . Th e resultin g equatio n i s a s follows :

VF = 1.14 3 

## 3 >

X 11.75 7

where : X = Distanc e from flame cente r (m ) R p = Poo l radius (m ) Fo r fatality , th e indden tflux leve l i s se tt o 1 0 kW/m 2
. Fo r injuiy , th e corresponding leve l i s 5 kW/m 2
. Thes e level s ar

e base d o n analysi

s o f numerou s source s o f

experimenta

l bur n dat a (Mudan , 1984) . Applying thes e two damag e criteria , th e abov e equation s wer e rearrange

d t o solv e for hazar

d distance s X 1 0 an d Xo 5 fo r fatalit y an d injuiy , respectively :



# [2 &-66 -



## ^••°- 3 0 

## -0^5i 8 E 

## ^

X„ K = 0.4 3 * £0.5 7 0 5 0.304 8 p

where : X 1 0 = Radius for expeae d fatalitie s (ft ) XQ S = Radius fo r expeae d injuries (ft)



# [2f tP.7 4

B 3 Yellow Book B3.1 Genera

l Descriptio n Th e Yello w Boo k indude s calculation s for poo l fires, vapo r dou d fires, an d vapo r dou d explosion s fo r gases ; an d poo l fires an

d vapo r dou d fires for liquids . Fo r gases , tw o differen tmethodologie s are used fo r vapo r dou d fires: th e flash fraction o f eac h ga s i s modele d a s a

n instantaneous releas e an d th e non flashed fraction i s modele d a s a continuou s releas e from a n evaporating poo

L I n bot h cases , dispersio n a s a neutrally buoyan

tdou d i s assumed . Th e flash fraction o f eac h gas i s use

d t o calculat

e th e vapo r clou d explosio n results . Sinc e there i s n o calculated flas h fraction for liquids , n o vapo r dou d explosio n result s are calculate d for liquids . B32 Vapo r Qou d Explosio n Calculation s fo r Gase s Reference : Yello w Book , Chapte r 4 , "Spra y Release, " p . 44 ; Chapte

r 7 , "Dispersion, " pp . 25-27 , an d Appendix 2 , p . 52 ; Chapte r 8 , "Vapo

r Qou d Explosion, " pp . 24-25 . Fo r gases , th e flash fraction for a spra y releas e i s calculated . Thi s fractio n i s the n multiplie d b

y th e tota l quantit y t o obtai n th e quantit

y instantaneousl

y i n th e air . Th e ma-rimn m fraction o f

thi s quantit

y tha ti s betwee n th e uppe r an

d lowe r flammability limit s i s calculated . Damage circles fo r th e resultin g quantit y can the n b e determined . Equations : Mass Flashe d (Chapter 4 , p . 44 )

w va p = **vap,

a " s wher e W ^ = mas s flashed (kg ) X^p ^ = flash fraction W g = mass store d (kg ) Th e flas h fraction i s calculate d from th e following equatio n (Chapte r 4 , p . 16 , equatio n (3)) :

Xvap.a Xvap,b -** T + -***£ - * J * -jr

where : Xygpt

, = weigh tfractio

n o f vapor befor

e expansio n (assume

d t o b e 0 fo

r calculatio n o f

th e flash fraction) T b = boilin g temperatur e (K ) T j = temperatur

e o f stored ga s compressed t o liqui d (K) C } = specifi c hea to f ga s compresse

d t o liqui d (J/kg-K

) h y = heato f

evaporation o f

ga s compressed t o liqui d (J/kg ) Flas h fractions for selecte d gase s ar e listed i n Chapte

r 4 , p.44 , Tabl e 1 .


# 1^ 0P.7 5

-68 - B3.2. 1 Quantit

y o f Vapor Contributin g t o Explosio n (Chapte r 7 , pp . 25-26) . Th e equatio n i n thi s sectio n estimate s th e amoim to f ga s i n th e explosiv e range . Thi s amoun tdevelop s as th e dispersio n progresses . Initially , an d dos e t o th e source , th e concentratio n i n a larg e par to f th e clou d wil l b e greate r tha

n th e upper explosiv e limit ; Mg , (th e amoun to f gas i n th e explosiv e range) wil l the n b e small . A s th e dispersio n progresses , Mg , inaease s t o a maximu m concentratio n tha

ti s reache

d when th e nr^-rimi- m concentratio n i s a littl e abov e th e uppe r explosive limi tAfte r thi s Mg , wil l graduall y drop again .

( % | = ERF ty/vi) - ERF {*fc) - -^ P EXP (-v 2 ) + 1&, EXP

(-v j V M /max V " i/f l

where Mg

_= amoun

to f ga s i n explosiv e rang

e (kg ) M = total amoun

to f ga s whic h ha s escaped (kg ) ERF(x ) = s error functio n = - | : f EXP (-t 2 )dt

(Thes e value s ar

e liste d i n Appendi

x 2 o n p 52. )

where
v = Pj/P^Vj-LnOMv 2 -! )

= ^ln(v ) 2 v 2 -l



### an d P x = upper explosiv e limi t(UEL ) P 2 = lower explosiv e limi t(LEL )

B3.22 Determinatio n o

f Damag e Circles (Chapte

r 8 , p . 25 )

Fo r th e limi tvalu e o f

certain types o f

damage(s ) th e relatio n i s expresse d below : R(S ) = C(S ) x (nE) 1/ 3 

# i4 l-69 -

, R(S ) = th e radius o f

a damag e circl e (m ) C(S ) = constantfor characteristi c typ e o f damag e (mJ" 1/3) A constantC(S ) goe s wit h eac h charaaeiisti c damag

e (S) , liste d o n p.25 . Fo r glas s damag e causin g injuiy , C(S ) = .1 5 ( a corresponding overpressur e i s no tgiven) . Onl y par to f th e tota l combustio n energ y i n th e explosiv e par

to f th e clou d i s availabl e for shock wave propagation . Thi s fraction i s symbolized b y th e yiel d faaor , n . Thi s yiel d faao r ca n b e divided int o tw o independentfaaor s n c an d n^ , i n whic

h n = n c x r^ . n c indicate s th e yiel d los s a s a resul to f th e non stoichiometr

y o f a clou d wit

h a continuou s developmento f fue l concentratio n i n th e explosiv e pa n o f th e doud ; i ti s putat30% . n,, , give s th e mechanica l yiel d o f th e combustion . Dependin g slightl y o n th e typ e o f gas , i ^ i s calculated as follows :
a . Isochori c combustion : i* ^ - approx. 33 % b . Isobaric combustion : n m = approx. 18 % Wher e a ga s clou d explosio n occurs , there i s probabl y som e for

m o f confinementwhic

h woul d resulti n isochori c combustio n an

d a probable valu e for i ^ o f 33% . n would the n equa l approximatel

y 10% . T o determine E , th e energ y conten to f

th e explosiv e pa n o f

th e vapor cloud , a

n equatio n i s give n as a

n exampl e o n p . 26 : E = mass x h c wher e h c = hea

to f combustio n (J/kg

)

B33 Yello

w Boo k Vapor Clou

d Fire Calculation s for Gase s Reference : Yello w Book , Chap . 5 , "Evaporation, " an d Chap . 7 , "Dispersion. " Th e evaporatio n rate fo

r th e poo l lef

tfollowin g th e flas

h o f a n instantaneou s releas e o f a chemica

l i s calculated using th e following : Wyg p = mass flashed Th e quantit

y remainin

g is :

wher e 

### w — w w "poo l "stor e "va p W,,,,, , = mas

s i n poo l (kg) W ^ e = mas

s stored (kg) Th e total volum e o f

th e chemica

l i n th e poo l i s calculate d using th e equatio n o n page 4 2 o f th e Yello w Book :

« • i 

# '» 

# " T,
+•2 -P.7 7

-70 -



### , wher e V j 0 

### = volum

e (m3 

### ) W | = mas s i n poo l (kg) P j = densit

y (kg/m

3 

### ) Th e poo l o

f liquid wil l sprea d ou t unti l th e minimu

mlaye r thicknes s i s reached

. Th e time , t e 

### , a t whic h thi s take s plac e i s bes t

calculated usin

g iteration s o

f th e equatio n o n pag e 23 :

*i, o ~2 x 

### ( n x

e 2 

### x C" x g x V li0

### x t\) P i ' 1 6



### *^xitxC"xgx

(-2- ) x

* 1#Bi n 

### x tj

-2 x ( n x C" x g x V 1/ 0 

### x o 1>nin 2 

### x t 2 

### ) 1/2 

### + * C"

x g x 6 XtaUl 2 

### x t 2 

### = 0

wher e

^ l o = 

### volum

e e ' = r s 

### x (T s 

### - T b 

### ) /hy X (-rxa s 

### ) 1/ 2 

### [p

. 16 ] T s 

### = ambien

t temperatur

e = 293° K T b 

### = boilin

g poin t o f th e chemica

l (°K ) a s 

### = therma

l diffusivit y o f substrat e = 1. 0 x IO" 6 

### m

2 

### / s fo r conaet e C = constan

t fo r spreadin g liquid s = 2 g = acceleratio n du e to gravit y = 9. 8 m/s 2 

### t e 

### = tim e fo r minimu mpoo l thicknes s t o b e attaine d (t o b e iterated ) (s ) p x 

### = densit

y o f th e chemica

l (kg/m

3 

### ) 5 limi n 

### = minimu

mthicknes s = 0.0 1 m T S 

### = coeffiden

t o f hea t conduaio n o

f substrat e = 1. 1 w/m

k Thi s equatio n i s use

d reiteritivel

y to comput

e value s o f t e 

### unti l aminimu

mpositive value i s found

. Th e evaporation rate at

th e minimu

mpoo l thicknes s i s calculate d a s follows :

M p 

### = 4 x {it x e 2 

### x C" x g x V 1# 0 

### x te 

### ) 1/2 

### - (8/3 ) xnxC"xgxex & 1§min 

### x

t t 3/ 2



### wher e M p = th e evaporatio n rat e at

th e minimu

mpoo l thicknes s (kg/m 2 

### s )

an d all other variable s are as define

d above

. A dispersion distanc e t o 50 % o f th e lowe r flammability limi

t i s calculate

d usin g th e equatio n o n pag e 1 5 o f th e Dispersion section o

f th e Yello w Boo k (wher e y , z , an d h all equa

l 0) :


# 1*

6P.7 8

-71 - C(x, y, z) m

[ 2 x i tx U

v x o y (x) x o x (x) ]

wher e C(x , y , z ) =
m =
a y (x ) concentratio n atcoordinat e x , y , z - = 50 % o f LF L (kg/m3 ) evaporatio n rate atminimu m poo l thicknes s (as describe d above ) (kg/sec ) aX b = 0.128X 090 5 an

d a2 (x ) = cX*

1 = 0.2X 07 6 (usin g value s i n th e tabl e o n page 1 0 for neutra l conditions )
B.3. 4 Vapor Qou d Fire Calculation s for Gase s (Based o n Fractio n Flashed , 50 % LFL ) Reference : Yello w Book , Chapte r 4 , "Spra y Release, " pp . 36,44 ; Chapte r 7 , "Dispersion, " p . 23 . Th e followin g equation s estimat e th e consequenc e distance for a vapo r clou d fire for gases , assumin g that a percentage o f

th e tota l amoun treleased i s immediatel

y vaporized ; thi s vaporized quantit y i s assume

d t o b e availabl e fo

r th e vapor clou d fire . Th e quantit y evaporating from th e poo l tha tremain s afte r flashing i s no tconsidere d i n thi s calculation . Th e flashe

d mass i s calculated a

s follow s (Chapte

r 4 , p 44) : Wf = Xy^W . W f = mass flashe

d (kg ) Xy^p^ = flash fractio

n (se e Sectio n B.3. 2 fo

r calculation ) W s = mas

s stored (kg ) Th e quantit

y W f i s then use

d as a n instantaneous source using equatio n 2 3 (p . 2 4 i n "Dispersion " section) , wher e th e concentratio n ata poin t(x , y , z ) a ttim e ti s give

n as : C(x,y, z, t ) = m

( 2 ir) 3/2 o XI

o„o ZI EXP (x-V v t)- 2°*r 2 EXP - -21

2 o ,

EXP (z-hY- + EXP (z+h) 2 2o ZI 2

where :

m = x - = y = z = h = source strengt

h fo r a n instantaneous releas e (kg ) coordinat e i n win d directio n (m ) coordinat e a trightangles t o win

d direaio n (m ) coordinat e i n vertica

l direaio n (m ) win d spee d (m/s ) sourc e height(m ) 

# 144
-P.7 9


### -72 -

a 

### x i a 

### Y i a 

### z i = 

### standar

d deviation s i n x , y , and z direction s fo r a n instantaneou s sourc e W e assum e tha ty , z , and h = 0 , an d tha tx = Uy twhere u w 

### i s win d speed , t o determin e th e distanc e th e dou d ha s travele d i n th e x directio n only :
c(x, 0,0 , t ) - m



### (2it) 3 / 2 

### o xz



### a„o ZI



### Fro m

whe n From p . 23 , CTjg, ffyi*

a X I = e I **

*

a ^ = a j x b * (jj a = c , x *

* a i » ty, Cj , dj , ej , 

### pag e 24 :
e ! = .1 3

a j = a/ 2
C j = c 

### an

d a 

### n ar e describe d

and f - are constants

f , = l
b j = b d I = d 

### b

y thes e equations :

Fro m Tabl e 1 0 o n pag e 10 , a = .128 , b = .905 , c = .20 . Therefore :

a 

### x i = 

### •**• * x

a X I ^Z l 

### C

m C =

Solv e fo r x : = .064x- 90 5



### = . 2 x *

7 6



### = concentratio n



## = w 8 

## w s 

### ( 2 rr) 3/ 2 

### (.064)(.2)(.13 ) x 2.66 5

X = 

### w. (2*) 3 / 2 (.13 ) (.064 ) (.13) C l/2-« 5 , _ , 0-3 „ 

### [ .01703C J


# 14

5P.8 0

-73 -

, B3rS Poo l Fire Calculation s fo r Gase s an d liquid s Reference : Chapter 4 , "Spra y Release, " p . 44 ; Chapte

r 6 , "Hea tRadiation, " pp . 8-14,19-35 . T o determin e th e hea tradiation into th e environmen tth e radiating surfac e (th e flame from th e burnin g pool ) i s see n as a

n uprightcylinde

r wit h diameter D an

d lengt h L . Th e radiation load q pe r uni tare a expose d whic

h i s experience d a

ta distanc

e r from th e cente r o f

th e fire i s (Ch . 6 , p . 8) : q ^ = fjxFx E where q r= radiatio n loa d (q ) a ta distance r from th e cente r o f th e fire (kW/m

2 ) r 1 = atmospheri c coeffiden to f transmission F = geometri c vie w faao r E = averag

e intensit y o f radiation (kW/m 2 ) B.3.5. 1 Atmospheric Coefficien to f Transmissio n Pa n o f th e radiated heati s absorbe d b y th e ai r betwee n th e obje a exposed t o radiation an d th e fire . Thi s reductio n i s taken int o accoun tb y r-., th e coeffiden to f

transmission . Th e siz e o f thi s coeffiden ti s dependen tupo n th e amoun to f water vapo r betwee n th e flam e an d th e objea , th e ai r temperature , an d th e relevan tdistance (r ) betwee n th e obje a an d th e cente r o f

th e fire . Th e relevan

tdistance (r ) i s th e unknow n variable fo

r th e purposes o f

thi s study , q, , th e radiation load , i s assume d t o b e 12. 5 kw/m 2 , th e intensit

y tha tcorresponds t o on e percen tprobabilit

y o f fatalit y for a 3 0 secon d exposure . Figure 2 o n p . 3 5 gives r-. as a functio n o f th e produ a o f

vapo r pressur

e an d relevan t distance . Th e vapo r pressur e i s determine

d b y multiplyin

g th e relativ

e humidit y b y th e saturate

d vapo r pressur e (give n i n Tabl e 1 , p.19 ) ata prevailing temperature . T o b e conservative , a valu e o f 1 0 percent wa s used for relativ e humidity . T o estimat

e th e relevan

tdistance , a

n iterative process , includin g calculations an

d estimate s o f

r a (atmospheri c coeffiden to f transmission) an

d F (geometri c vie

w faaor ) from B.3.5.1 , B.3.5.2 , an d B.3.5.3 , wa s used . Assumin g a relevan tdistanc e an d multiplying tha

testimat e b y th e vapo r pressur

e yield s a n estimat e for t , usin g th e tabl e o n pag e 35 . Thi s valu e fo

r tca n the n b e use d i n calculatin g th e view faao r (F) , a s described i n B.3.5. 2 an

d B.3.5.3 . Th e estimat

e for F i s use

d t o determine anothe r estimate fo r th e relevan tdistance . Thi s ne

w assume d distanc e i s used t o estimat

e another valu e fo

r t , an d th e step s abov e ar e reiterated . Thi s reiterative proces s i s used unti l th e relevan tdistanc e approaches a singl e value . B.3.5. 2 Th e Geometric Vie w Facto r F Th e effe a o f

th e geometrica

l shap e o f th e flame an

d th e place an

d orientatio n o f

th e expose d obje a ar

e incorporated i n th e vie w faao r F . Th e siz e o f th e view faao r i s determine d b y th e lengt

h t o diameter rati o o f th e flame (Chapter 6 , p . 9) .



### rr / / V " hi. =4 

### 2 m



# \^oP.8 1

-74 - where L f = lengt h o f th e flame (m ) d = diameter o f

th e flame (m ) m " = rat e o f evaporatio n (kg/m**s

) g = acceleratio n du e t o gravit y = 9. 8 m/

s p = densit

y o f air (at18° C = 1.21 3 kg/m3 ) 2

Th e diameter o f

th e flame i s assumed equa l t o th e diamete r o f

th e poo l Th e diamete r o f th e poo l i s calculate d from th e volum e o f propane i n th e pool , assuming th e poo l spreads ou tt o a thicknes s o f .0 1 m . Th e calculatio n for th e rate o f evaporatio n (m" ) i s dependentupo n whethe r th e store d materia l i s a liqui d wit h a boilin g poin tbelo w th e ambien ttemperatur

e o r abov e th e ambien

ttemperature . Liquids wit

h a boilin g poin tbelo w ambien ttemperatur

e are gase s store d under high pressur e conditions . Th e equatio n i s given i n Chapte r 6 , p . 10 :

xn " = -rr- • IO" 3 kg/m 2 se c h v

wher e h c = hea

to f combustio n (J/kg) h y = hea to f vaporizatio n (J/kg

) Fo r liquid s wit

h a boilin g poin tabove ambien ttemperatur

e (Ch . 6 , p.ll) :

^ . 10" 3 CpA T + h v

wher e C p = specifi c hea

to r hea tcapadt y a tconstan tpressur e (J/kg.K ) A T = boilin g temperatur

e - ambien

ttemperatur

e (K) Th e valu e o f

th e vie w faao r (no tth e size ) ca n b e determined b

y solvin g th e initial equatio n for radiation load fo r F : q^

. = fjxFx E F *

= q^xE ) B.3.5. 3 Intensit

y o f Radiatio n o f

th e Fire Th e valu e fo

r E , th e averag

e intensit y o f radiation (W/m 2 ) , i s dependento n bot h th e typ e o f

fue l an d o n th e diameter o f

th e pool . Th e magnitud e o f th e averag

e intensit y o f radiation i s given o n Tabl e 3 , p . 2 1 fo r fou r gases : butane , propane , ethylene , an d propylene . Th e valu e fo r th e othe r substances i s calculated usin g th e equatio n i n Chapte r 6 , Appendi

x 2 , p . 3 2 fo

r liquids : 

# mP.8 2

-75 - 

### 0.3 5 

## f b 

## ° C„AT+h v • 

### 7 2 1 „ . 

### fe . . 

### IO 3 [ C p A T + h v IO 3

.6 1 b c + 1

wher e E = radiation intensit y (W/m 2 ) hj . = hea to f combustio n (J/kg) C p = heatcapadt

y (J/kg-K ) h y = hea to f vaporizatio n (J/kg

) A T = boilin g poin t- ambien ttemperatur

e (°K ) Th e lengt h t o diamete r ratio can the n b e determined usin g th e equatio n i n Chapte r 6 , p . 9 :

Lf

_ 4 2 M" PaVff^

Tabl e 1 o n p . 2 4 give s vie w faaor s betwee n a vertica l uprigh tcylinder an

d a surfac e o n th e ground . Th e tabl e lists th e view faaor s as coordinate s between th e rati o o f flame lengt

h t o radius an

d th e rati o o f

th e distance o f

th e obje a from th e fire t o radius . Thes e ratios ar e diagramme

d i n Appendi

x L Usin g th e sectio n o f th e tabl e tha

tgive s maximu

m view faaors , th e ratio a/ b i s assume

d t o b e th e lengt

h t o radius ratio an d i s take n t o b e twice th e flame lengt h t o diameter ratio. Usin g th e know n ratio a/ b an d th e vie w faao r F , th e ratio c/

b ca n b e estimate d an

d th e relevan

tdistance (c ) t o th e obje a receivin g radiation can b e determined . Usin g thi s new assume d distance , a ne

w valu e fo

r T 1 ca n b e estimated i n a reiteratio n o f th e process , until th e distance approaches a singl e value . B3.6 Vapor Clou

d Fire for liquid s (Dispersio n Distanc e t o 50 % LFL ) Reference : Yello w Book , Chapte r 5 , "Evaporation, " Pp . 29-38 ; Chapte r 7 , "Dispersion, " Pp . 15-16 . Th e calculation s i n thi s sectio n model th e consequence distanc e i n a vapor clou d fire when th e materia l evaporates from a poo l o n th e groun d rathe r tha n flashin g into a vapo r state afte

r a n instantaneou s release . Th e consequenc e distance t o a concentratio n tha ti s 50 % o f

th e lowe r flammability limi t(LFL ) i s modeled . Th e 50 % LF

L figure i s a conservativ

e level tha

taccount s for uncertainties lik e th e uneve n dispersio n withi n th e clou d an d th e estimate d valu e o f

th e lowe r flammability limi tT o determin e th e mass flux o f

evaporatin

g non-boilin g liquids , th e followin g equatio n i s used (Chapte r 5 , P . 33) :



# '4* .P.8 3

-76 -

j & = 2.10- 3 tf;Z* rk£. c -g- (P , - 2- H for: P

K < 2x10* Pa * * *



### wher e
n 

### mm , = mas s flux o f

evaporatin g liqui d (kg/m** ) U w 1 0 

### = win d spee d a t1 0 meter s = 3 m/ s r 

### pooi, c = 

### radiu s o f

circula r poo l = 46. 8 i n M = molecula r weigh t R= mola r ga s constan t= 83X10 3 

### J/kmol- K T n b 

### = temperatur e o f

non-boilin g liqui d = ambien ttemperatur e - = 29 3 K P w 

### = saturate d vapo r pressur e o f liqui d (Pa ) P m = partia l vapo r pressur e i n surrounding s = 0 fo r liqui d (Pa ) I n orde r t o calculat e th e dispersio n t o 50 % LFL , th e equatio n fo r th e concentratio n fo r a continuou s sourc e o n p . 1 5 o f

Chapte r 7 i s used :
C(x,y,z) *

- 0 

### _ _^ , . EXPJ

£—\ .\EXP(- 

### <z 

### : h)2 

### ) + EXp(- {z 

### : h)2 

### )) 2nU v {x)o x (x) (

2o y 2 (x)j [ { 2o 2 U ) J (

2o 2 (x) j

J



### wit h y , z , an d h = 0 , thi s equatio n reduce s to :

C(x) = rt 

### 2 n U v 

### o y 

### (x ) o z 

### (x)

wher e C(x ) = concentratio n a s a functio n o f x onl y (kg-m' 3 

### )

m = sourc e strengt h (leg's" 1 

### ) U w 

### = win d spee d a t1 0 m heigh t(m/s ) h = sourc e heigh t(m ) ff y 

### (x) = aX b 

### an d a 2 

### (x ) = cX* 1 

### , (se e p . 1 0 fo r practica l formula e fo r o y 

### an d c-_ ) T o calculat e m , th e sourc e strength , w e multipl y m^ , (kg/m 2 

### sec ) th e mas s flux o f th e evaporatin g liquid , b y th e are a o f

th e poo l (m 2 

### ) . Th e equatio n i s the n solve d fo r X , th e distanc e t o th e 50 % LF L concentration .


# W RP.8 4



### BA AIChE-Sponsore d Cours e Material s B4. 1 Genera l Descriptio n Th e America n Institut e o f

Chemica l Engineer s (AIChE ) cours e materia l indude s calculation s fo r poo l fires an d vapo r dou d fires fo r gase s an d liquids . Fo r vapo r dou d fires fo r gases , th e flash fraction o f eac h ga s i s modele d a s a n instantaneou s release ; th e AICH E materia l explain s tha tth e consequenc e distanc e produce d b y th e initia l flash fraction dou d i s s o muc h large r tha n th e consequenc e distanc e fo r th e remainin g non-flashe d pa n tha ti tdominate s i n assessin g th e hazard area . Th e calculation s fo r vapo r dou d explosion s an d BLEVE S appea r incomplet e an d canno tb e use d a s methodologies . BA2 Vapo r Clou d Fir e Calculatio n fo r Gase s Reference : AICh E Pp . B-6 5 an d B-85 ; D- 9 - D-10 . Th e fractio n o f

liquifie d ga s vaporize d (v ) i s give n o n p . D-9 :
v = fraction o f

liqui d vaporize d

v = l-expiCp/hyCT, , - T a 

### ) } wher e C p = specifi c hea t(Btu/lb°F ) h y = laten thea to f

vaporizatio n (Btu/lb ) T b 

### = normal boilin g poin t(°F ) T x 

### = temperatur e o f

liqui d strea m (°F ) W e the n multipl y th e fraction o f th e liqui d vaporize d b y th e quantit y release d t o determin e th e amoim to f vaporize d materia l (Q) . T o determin e th e distanc e t o 50 % LFL , th e equatio n o n p . B-8 4 i s used :

(Ut)°- 2 x 2 +y 2 + z2 *<* - y> *• c > - ,v » <?(%)«/»*«/» e x p C 2



### -V . 0 > 0 t ) 

### = 1310/(Ut) 2



### - 6 2 

### fo r neutra l condition s wher e X = concentratio n a tth e cente r o f th e clou d (assum e 50 % LFL ) a ttim e t(kg/m 3 

### ) U = win d spee d (m/s ) t= tim e (s ) U t= distanc e (m ) Th e equatio n i s solve d fo r U tth e distance , b y includin g th e 50 % LF L concentratio n a s X an d th e quantit y o f vaporize d material , Q .



# IS OP.8 5

-78 -

, B.4 3 Vapor Qou d Fire Calculation s fo r liquid s Reference : AICh E Pp . D- 2 - D-5 , D- 9 - D-10 . T o determine th e rate o f

evaporatio n from a circula r pool , th e area o f

th e poo l mustfirstb e determined . Thi s i s calculated b

y dividing th e total volum e o f liqui d b y th e thicknes s o f

th e pool , whic

h i s estimate d for differen tsurfac e types i n Tabl e I o n p . D-4 . Th e radius o f th e poo l i s the n determined an d use d i n th e followin g equatio n for evaporatio n (p . D-2) : E = K , U^ n ) / P +n

¥ 4+I1 >< 2+n > (kg/isec

) where K * = a"U

0 D 2n/ < 2+I 0 -jj-n/P+n

)

° ~ s = vapo r densit y (kg/m3 ) R T P s - = saturate d vapor pressur

e (N/m 2 ) M = molecular weight(kg/kmol) R = universa

l ga s constan t(8314. 3 J/mo

l K ) T = ambien

ttemperature , K Value s o f n , a", K'/U 0 ar

e give n i n Table I

I (usin g neutra

l stability) . Th e distance tha

ta vapo r clou d disperses from a liqui d poo l i s give n b y th e equatio n o n p . D-9 : &.. = {(36.8)(Q)/(U)(C L )} 0 ' 55 2 (m ) wher e d 1 = distance a twhic h clou d i s dilute d t o LFL (m ) Q = source strengt h o r volumetri c vapo r escap e rat e (m 3 /sec ) U = win

d velodt y (m/sec) C ^ = lower explosiv e limi t(vol^n^/vol^ )

(use d 50 % LE L versus LEI, ) Th e volumetri c vapo r escap e rate (Q ) i s calculated from th e Evaporation rate usin g th e Idea l Ga s Law . Th e evaporatio n rat

e (kg/s ) i s convene d t o mole s usin g th e molecular weight, mole s are convene d t o liter s a tth e prevailing temperature , an d liters ma

y the n b e convene d t o m 3
. B.4. 4 Pool Fire Calculation s fo r liqui d an d Gase s Reference : AICh

E Pp . D-1 6 - D-29 . Th e AIChE methodolog

y doe s no tdistinguish betwee n liquid s an d gase s i n th e calculatio n o f th e therma

l flux ata specified distance from a burnin g pool . T o determine th e liqui d burnin g rate (v) , th e followin g equatio n i s used (P . D-17) :

v = v w {l-exp(-k x d) } (fo r a poo l o f diameter d ) wher e -k j = attenuatio n coeffiden t v = liquid burnin g rate (lbs/s ) 

# 15 1P.8 6

-79 -

v a = liqui d infinit e poo l burnin

g rate = .003 0 h,Jh\ d = poo l diameter (ft) h c = hea

to f combustio n (Btu/lb ) h' v = sensibl e heato f vaporizatio n (Btu/lb ) = sensibl e heat+ latenthea t Th e mas s burnin

g rate can the n b e calculate d (p . D-17) : M = v p where M = mas

s burnin g rate (lb/ft

2 sec ) v = liqui d burnin

g rate (in/min ) p = densit

y o f th e liqui d (lb/ft

3 ) Th e mass burnin

g rate i s the n used t o estimat e th e rati o o f

flam e heigh t(h ) t o poo l diameter (d ) (p . D 18) :



### 4 

### =4 2 a m

P a (gd) s

where
m = mas

s burnin g rate (kg/m 2 sec ) p a = densit

y ambien tai r (1.20 6 kg/m

3 ) g = acceleratio n o f

gravit y = 9. 8 m/sec2 d = poo l diameter (in ) Therma l flux i s calculated b

y dividin g th e total hea

t(Q ) b y th e surfac

e are a o f th e flame envelop e (S) . Tota l heatavailable durin

g th e poo l fir

e is : Q =(h c )(m)(A ) (Btu/sec ) wher e h c = hea

to f combustio n (Btu/lb o r cal/g ) m = mas

s burnin g rat e (lb/ft

2 sec ) A = poo l are

a (f r o r nr ) Poo l are a i s determine

d b y dividin g th e total volum e o f

th e liqui d b

y th e thicknes s o f

th e pool . Thicknesse s fo

r spreadin g pool s ove r differen

tsurface s ar e liste d i n Tabl e I , page D-4 . Onl y a fractio n o f

th e tota l heati s radiated from th e surfac e o f th e flame envelope . Thes e fractions ma y b e rea d from Tabl e II , page D-5 . Th e surfac e hea tflux (q 0 ) ca

n the n b e determined (p . D-19) . q 0 = Q/ S (Btu/ft 2 hr )

wher e S = surfac

e are a o f cylindrica

l flam e = 2-r h + -rr

2 Q = tota

l hea t 

# IS *P.8 7

19) : -80 - Th e heatabsorbe

d (q,. ) b y a receiver a

tvarious distances (x ) from th e poo l cente r i s given b y (p . D wher e q 0 = hea

tflux a tflame surfac

e (Btu/ft

2 hr ) E^ . = receiver surfac

e absorptivit

y (fro m Tabl e IH

, D-2 5 - assume

d t o b e 1 , al l hea tabsorbed ) T x = atmospheric transmissivit y atdistance X = 1-E

„ F x = view fado r from receiver t o flame E^ , = emissivit

y o f wate r i n air Th e atmospheri c transmissivit y i s estimated a s a function o f distance (x ) from th e cente r o f th e flame t o th e receive r time s th e partia l pressur e o f water . E w i s rea

d from a grap

h o f emissivit y versu s th e partia

l pressur e o f water (atm ) time s th e distanc e (ft) foun

d o n p . D-26 , assuming th e partia l pressur e i s .002 4 for wors tcas e winte r conditions . Th e vie w faao r (F ) i s rea d from table s o n pp . D-2 7 - D-29 . I ti s plotte d a s a functio n o f distanc e (D ) from th e flame centerlin e t o th e receiver flame radius an d th e plots ar

e arrange d b y th e flame height/poo l diamete r ratio. Th e distanc e i s initiall y assume d t o find a valu e for E ^ an d q

_i s equa l t o 12. 5 kw/m

2
. Th e equatio n i s the n solve d fo

r F ran d th e distanc

e "D " ca n b e determined . Successive approximation s o f th e calculation s fo r th e valu e o f

F x are the n calculated usin g th e new value s fo r th e distanc e unti l on e valu e i s approached .



# IS3 >P.8 8

B. 5 Green Book Th e Technica

l Guidance for Hazard

s Analysi s ("Gree

n Book" ) contain s calculation s for th e consequenc e distance s fo r Vapo r Qou d Hres , where 50 % o f th e lower flammability limi t(LFL ) o r anothe r fraction o f th e LF L ma

y b e use d as concentratio n level . Reference : Gree n Book , Appendi x G , "Equation

s Use d fo r Estimatio n o f

Vulnerabl e Zones. " Th e rat e o f releas e o f

a chemica

l i s neede d fo r calculatio n o f th e distance fo r a specifi c concentration . I t i s dependen to n th e quantit y o f chemica l released , th e natur

e o f th e releas e scenari o (i.e. , poo l o f liquid) , an d th e propertie s o f

th e chemica

l released . Fo r spille d pool s o f chemicals , th e rate o f

releas e i s usuall

y taken t o b e th e evaporatio n rate (rat e o f volatilization) . Usin g th e assumptions presented above ; th e followin g equatio n i s used t o calculat e th e rate o f

releas e t o air for liquid s (i n lbs/min) :

OR (6 0 sec/mi n x MW x K x A x VP

x (92 9 cm 2

/ft 2 ) Rx (Tl+273 ) x (760 mmHg/atm ) xlSAg/lb

where Q R = rat

e o f releas e t o ai

r (lbs/min ) M W = molecular weigh t(g/ g mole ) K = gas phas e mass transfe r coeffiden t(cm/sec) A = surfac

e are a o f spille d materia

l (ft 2 ) V P = vapo r pressur

e o f materia l a ttemperatur

e T l (m m Hg ) R = 82.0 5 at

m cm 3 / g mol e K , an d T l = temperatur

e a twhic h th e chemica

l i s store d (°C ) Th e equatio n fo

r th e evaporation rate (rat e o f volatilization ) ca

n b e rewritte

n as follows :

0R B 0.16 2 XMWX

KxA X

VP J?(Tl+273 )

K can b e estimate d base

d o n a know

n valu e fo r a referenc

e compoun

d a s follows : K = K ref

x(MW reJ ^vTW) 1/ 3 Usin g water as th e referenc e compound : K-xr f = K watc r = 0.25x(U) 07 8 where : U = windspee d (m/sec ) Combining th e two equation s above : K = 0.25 (U) 07 8 x (18/MW) 1/ 3 Combining equation s fo

r Q R an d K yield s th e followin g equations (Gree n Boo k p . G-2) : 

# s* VP.8 9

OR -82 - 0.16 2 x 0.2 5 x (D) 0

- 7 8 x (18) 1 / 3 x Mff 2/3 x A X

VP RX (Tl+273 )

QR _ . 0.10 6 x (P) 0 * 7 8 xMH 2 '3 xAxVP W RX

{Tl+273)



### Calculation o

f th e surface are a(A) o

f th e spille d materia l i s carrie d ou t

a s describe

d below

. Th e followin

g assumption s are use

d t o calculat

e th e surface are ao

f th e spill : Densit y = 62. 4 lb/ft

3 

### (Le. , al l liquid s ar e assume d t o hav e th e sam e densit y a s water ) Dept h o f poo l i s 0.03 3 ft

( 1 cm ) Th e surfac e are ao

f th e spilled liqui d (ft 2 

### ) i s (Gree n Boo k p G-3) :
e5JI__£ ) 0.49X0 5 62.4 lb/ft 3 x 0.033f t



### wher e QS = quantit

y spille d (lbs ) an d A = surface are a(ft 2 

### ) Substituting fo

r A in th e abov

e equatio n fo

r releas e rate , th e quantit

y released to ai

r pe r minut e (QR ) ca n b e estimate d a s follows :

0 „ = 0.10 6 J C (P) 0 7 8 xMti

2 '3 X 0.4 9 X QS x VP 82.0 5 x (Tl+273 )



### Fo r gases , i t i s assume d (Green Boo

k p . 3-3 ) tha

t th e entire mas s i s released in th e ten minutes : Q S (lbs ) Q R = 

### 1 0 minute s wher e Q S = quantit

y spille d (lbs )P.9 0
-83 -

, Th e followin g equatio n wa s use d t o deriv

e th e distanc e t o a concentratio n (C) . Th e concentratio n downwin d o f a releas e i s give n b y (Gree n Boo k p . G-4) :



### OR 1mO y Oz U

for a groun

d leve l releas e wit

h n o effective plum e risk where : C = airborn

e concentratio n (g/m 3 ) (assume d 50 % LFL ) Q R = rat

e o f releas e t o air (g/sec ) it = 3.14 1 a y x a z = dispersio n deviation , horizonta l (y) , an d vertica l (z ) U = windspeed (m/sec )

Thi s equatio n i s the n solve d fo r th e produ a o

y a v th e dispersio n deviation .

a o 2 ? y * iit f

(50 % LFL)

T o determin e th e downwm d distance (d) , Exhibi

tG- 1 o n p . G- 6 lists o y an d a z a s functions o f

d , usin g th e stabilit y categor y D for open-countr

y conditions : Oy = .0 8 d ( 1 + .000 1 d)" 1/ 2

o z = .0 6 d ( 1 + .001 5 d)" 1/ 2 d = downwin

d distance , for 10 2 <d<10 4 (m ) However , th e produ a o f

a y an d o z derive

d from th e downwin

d concentratio n equatio n canno tb e used t o solv e th e produ a o f

a y (d ) an d o z (d) . Th e valu e from thes e successiv e approximation s wa s the n compare d t o th e numerica

l valu e o f th e OyOz produ a from th e concentratio n equation t o estimat e th e distance (d) .



# IS QP.9 1

APPENDK C HAZAR D CRITERI

A



# ffftP.9 2
-85 -

Appendi x C Hazar d Criteri a C l Explosio n Overpressur e C1. 1 Damage an d Injur

y from Blas tWave

s Blas twaves fro

m acddenta l explosion s ca n caus e damag

e t o peopl e an

d propert y b y subjectin g them t o transientcrushin

g pressures an

d winds . Relativel y simpl e concepts hav e bee n used t o quite effectively correlat e blas twav

e propertie s wit

h damage . Th e concep tstate s tha tdamag e i s primaril

y a functio n o f eithe r th e pea

k overpressure , th e impuls e o r som e combinatio n o f thes e faaors . Pea

k overpressur

e i s mos tcommonl

y used . Criteria fo

r pea k overpressure

s causin g persona l injur y are given i n Exhibi

tC-l , including injur

y from dire a blas teffect

s an d from flying glass . Guideline s fo r pea k overpressure

s require d t o produce propert

y damag e are presente d i n ExhibitC-2 . Thes e dat a are largely based o n empirica l observations . Ther

e seem s t o b e genera

l agreemen

tbetween source s o n th e dat a presente d i n ExhibitC-2 ; however , th e sam e i s no ttru e for th e dat

a presente d i n Exhibi

tC-l . Accordin g t o ExhibitC-l , lun g damag e ma y occur a t overpressure

s o f 1 0 psi . According t o othe r sources , threshol d lun g damag e ma y no toccu r unti l pea

k overpressure

s reac h 3 0 t o 4 0 ps i (Grelecki , Richmond 1968) . Th e value s fo r corresponding fatalitie s als o vary. According t o th e Exhibit, th e lowes toverpressur e dte d fo r fatalit y from dire a blas teffect

s i s 14. 5 psi . According t o anothe r source , a 1 % mortalit y rat e i s probabl e at27. 0 psi . Other s dt e value s i n th e range o f 3 5 t o 120 ps i a

s th e threshol d overpressur e valu e for fatalities , 20. 5 t o 18 0 ps i for a 50 % fatalit y rate , an d 2 9 t o 25 0 ps i fo r a 99 % fatalit y rate (Grelecki , Richmon d 1968 , Lee s 1980) . Exhibit s C-3 an d C-4 sho w how lethalit

y an d injuiy var

y wit h bot h overpressur

e an d th e duration o f

th e blas twave . Exhibi

tC-5 show

s simila r dat a a s a functio n o f

bot h pounds o f

TN T an d range i n fee t Exhibit s C- 3 throug h C- 5 presentpotential injur

y level s resultin g fro

m dire a exposur

e t o blas t overpressure

s i n a n ope n area. The

y d o no ttake into accountinjuries resulting from propert y damag e presente d i n Exhibi

tC-2 . Fo r example , substantia l injur y an d possibl e death s ma

y resul tfrom th e shatterin g o f

conaet e wall s at2. 0 t o 3. 0 psi . I n plannin g wit

h regar d t o injui y t o personnel , th e followin g guideline s hav

e bee n recommende

d (Brasi e an

d Simpso n 1968) :

• Personnel i n area s subje a t o overpressures greater tha n abou t2 ps i ar e likel y casualtie s from fragmentation o r self-impa a againstobjects .

• Personne

l beyon d th e unde

r 1 ps i overpressur

e rang e shoul d b e reasonabl y saf e insid e a reinforce

d struaur e awa

y from window

s or , i f outdoors , lying o n th e ground . Nazari o (1988 ) recommends tha tal l personnel i n ope n terrain b e evacuate d i f th e potential o f

0. 3 ps i overpressur

e exist s an d recommends evacuating personnel i n buildings tha tmigh texperienc e a

n overpressur

e exceeding 1.

0 ps i (0.2 5 ps i overpressur e if th e building ha

s windows) . According t o th e AICh

E (1987) , th e usua

l procedur

e for contro l room desig

n for plant

s wher e there ma

y b e th e potentia

l fo r explosion s i s t o desig

n th e contro l room fo

r a pea k overpressur

e o n th e order o f

1 t o ~ 3 psi .



# [S« ?-86 - EXHHUTC-1 . HUMA

N I N JUR Y CRITERI

A (Indude s Injur

y from Flying Glas s an d DirectOverpressur e Effects )

Overpressur

e (psi )

0. 6

1.0 - 2. 0

1. 5

2. 0 - 3. 0

2. 4

2. 8

3. 0

3. 4 4. 0 - 5. 0

5. 8

6. 3 Injur y

Threshol d for injuiy from flying glass * Threshol d for ski n laceratio n from flying glas s Threshold for multipl e ski n penetration s from flying glas s (bar

e skin) * Threshold for seriou s wounds from flying glas s Threshold for eardru

m ruptur e
10 % probabilit

y o f eardru m ruptur e Overpressur

e wil l hur l a perso n t o th e groun

d

1 % eardru

m ruptur e Seriou s wound s from flying glas s nea r 50 % probabilit

y Threshold for body-wal

l penetratio n from flying glas s (bar

e skin) * 50 % probabilit

y o f eardru m ruptur e Comment s

Base d o n studie s usin g shee p an

d dogs Base d o n Arm y dat a
Base d o n studie s using shee p an

d dogs
Base d o n Arm y dat a
Conflicting dat

a o n eardru m ruptur e Conflicting dat

a o n eardru m ruptur e On e source suggested a

n overpressur

e o f 1. 0 ps i fo r thi s effe a No ta seriou s lesio n Base d o n Arm y dat a
Base d o n studie s using shee p an

d dogs
Conflicting dat

a o n eardru m ruptur e Source

(Fletcher , Richmond , an d Yelvenon 1980 ) (Lee s 1980 ) (Fletcher , Richmond , an d Yelvenon 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Brasi e an d Simpso n 1968 ) (U.S . DO T 1988 ) (Lee s 1980 ) (Fletcher , Richmond , an d Yelvenon 1980 ) (Lee s 1980 )

Interpretatio n o f

table s o f dat apresente d i n reference

.



## UaO-87 - EXHIBITC-1 . HUMA

N INJUR Y CRITERI

A (Indude s Injur

y from Flyin g Glas s an d DirectOverpressur e Effects ) (continued )

Overpressur

e (psi ) Injur y Comment s Source

7. 0 - 8. 0 Seriou s wound s from flyin g glas s nea r 100 % probabilit

y 10. 0 Threshol d lun g

hemonhag e Base d o n Arm y dat a
No ta seriou s lesio n (applie s t o a blasto f lon g duration (ove r 5 0 msec) ; 20-3 0 ps i require

d for 3 msec duration waves ) (Lee s 1980 ) (U.S . DO T 1988 )

14. 5
16. 0

17. 5

20. 5

25. 5

27. 0

29. 0 Fatalit

y threshol d fo r dire a blas teffect

s 50 % eardru

m ruptur e 10 % probabilit

y o f fatalit y from dire a blas teffect

s 50 % probabilit

y o f fatalit y from dire a blas teffect

s 90 % probabilit

y o f fatalit y fro m dire a blas teffect

s 1 % Mortalit

y

99 % probabilit

y o f fatalit y from dire a blas teffect

s Fatalit

y primaril y from lun g hemonhag e Som e o f th e ea r injuries woul d b e sever

e Conflicting dat

a o n mortalit y Conflicting dat

a o n mortaht y Conflicting dat

a o n mortalit y A hig h inddenc e o f

severe lun g injurie

s (applie s t o a blas to f lon g duration (ove r 5 0 msec) ; 60-7 0 ps i require d for 3 msec duration waves ) Conflicting dat

a o n mortalit y (Lee s 1980 ) (U.S . DO T 1988 ) (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (U.S . DO T 1988 )

(Lee s 1980 )



# l- l-88
- EXHIBI T C-2 . PROPERT

Y DAMAG

E CRITERI

A

Overpressur

e (psi ) Damage Source(s )

0.0 3

0.0 4

0.1 0 0.1 5 0.3 0

0. 4

0. 5 - 1. 0

0. 7 1. 0

1. 0 - Z O

1. 3 Occasiona l breakin g o f large glas s window s alread y under strain Lou d nois e (143dB) . Soni c boo m glas s failur

e Breakag e o f windows , small , unde

r strain Typica l pressur e for glas s failur

e "Saf e distance " (probabilit

y 0.95 n o seriou s damag

e beyon d thi s value) . Missil e limi tSom e damag

e t o hous e ceilings . 10 % windo

w glas s broken . Minor struaural damag

e
Shattering o f

glas s windows , occasiona l damag e t o window frames. On e source reporte d glas s failur

e a t0.14 7 psi

Minor damag

e t o hous e structure

s Partia l demolitio n o f

houses , mad

e uninhabitable Shatterin g o f corrugate

d asbesto s sidin g Failur e o f corrugate

d aluminum/stee

l panelin g Failur e o f woo d sidin g panel s (standar d housing construction ) Stee l fram

e o f cla d building slightly distorted (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 )

(McRae 1984 , Lee s 1980 ) (Brasi e an

d Simpso n 1968 , .Ai r Forc e 1983 , U.S . DO T 1988 , Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Brasi e an

d Simpso n 1968 , Ai r Forc e 1983 , U.S . DO T 1988 , Lee s 1980 ) (Lee s 1980 )

2. 0 Partia l collaps e o f

wall s an d roof s o f house s (Lee s 1980 )



# SSlr-89 - EXHIBI T C-2 . PROPERT

Y DAMAG

E CRITERI

A (continued )

Overpressur

e (psi ) Damage Source(s )

2. 0 - 3. 0

13 2-5 3. 0

3. 0 - 4. 0

4. 0
4. 8 5. 0

5. 0 - 7. 0 7. 0 7. 0 - 8. 0 Shattering o f non-reinforced conaet e o r cinder block wall panel s (1. 5 ps i accordin g t o another source )

Lowe r limi to f seriou s struaural damag

e 50 % destructio n o f

brickwor k o f hous e Stee l fram

e building distorted an

d pulle d awa

y from foundations Collaps e o f

self-framin

g stee l pane

l building s Ruptur e o f oi l storag e tank

s Snappin g failur e - woode n utilit

y tank s Claddin g o f ligh tindustria

l building s rupture d Failur e o f reinforce d conaet e struaure s Snappin g failur e - woode n utilit

y pole s
Nearl y complet e destructio n o f

house s Loade d trai n wagon s overturne

d Shearing/flexur

e failur e o f bric k wall panel s (8-1 2 inches thick , no treinforced)

Side s blow

n i n o f stee l fram

e building s Overturnin

g o f loade d rai

l car s (Brasi e an d Simpso n 1968 , jAi r Forc e 1983 , U.S . DO T 1988 , Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Brasi e an d Simpso n U.S . DO T 1988 , Lee s 1980 ) (Lee s 1980 ) (McRae 1984 ) (Brasi e an d Simpso n 1968 , Lee s 1980 ) (Lee s 1980 ) (Lee s 1980 ) (Brasi e an

d Simpso n 1968 , Ai r Forc e 1983 , U.S . DO T 1988 , Lee s 1980 ) (Ai r Forc e 1983 ) (Brasi e an d Simpso n 1968 , U.S . DO T 1988 )



## MUS)P.9 7

-90 - EXHIBI T C-2 . PROPERT

Y DAMAG

E CRITERI

A (continued )

Overpressur

e (psi ) Damage Source(s )

9. 0 Loade d trai n box-car s completel y demolishe d (Lee s 1980 ) 10. 0 Probabl e tota l destructio n o f building s (Lee s 1980 ) 30. 0 Stee l tower s blow n dow n (Brasi e an d Simpso n 1968 , Ai r Forc e 1983 ) 88. 0 Crate r damag e (McRa e 1984 )



# {.iA

### -91

- EXfflBITC-3 . LETraALTT Y CURVE

S (Fo r a 15 4 l b Perso n i n Free Strea m Situations )

kP a P U

Maximu m inciden t overpres sure 10.00 0 5,00 0

2.00 0

1.00 0

SO O 20 0 61 9 9 9 * lathalit y 50 % lethalit y —- - — I H lathalit y

0. 2 0. 4 1. 0 2 « 71 0 2 0 4 0 10 0 20 0 100 0 Ouratio n e f poaitiv e ina**m ovorpreMure . rma c SOO O

EXHIBI T C-4 . LETHALIT

Y AN D INJUR Y CURVE

S (Fo r a 154 I

b Perso n i n Fre e Strea

m Situations )

kP a 10 *

10 3 Maximu m inciden t overpres sur a IO *

1 0

0. 1 I H Lethalit y

P *
1.00 0

10 0

1 0

0. 1 •
0.0 1 Threshol d lun g dameo a -»«*«•*• « S0 % Eardru m ruptur e • - 9S H Eardru m protectio n wit h muff s =^ = 95 S Eardru m protectio n w/ o muff s —. _ . _

-f - •+ • 0. 2 1. 0 1 0 10 0 Ouratio n o f positiv e inciden t ovarpranu r Notes : mse c = millisecond s kP a= kilopascal s = 6.89 5 ps i ps i = pound s pe r

squar e inc h = 0.145 0 kP a Source : U.S

. DO T 1988 , Kokinaki s an d Rudolph 1982

. — I — 100 0 .mse c 10.00 0



# Itf-92 - EXHHH T C-5 . AIR-BLAS T CRITERI A FO R PERSONNE

L STANDIN

G I N TH E OPE N P.9 9

10 0 RANG E I N FEE T 10,00 0

Source : U.S . DO T 1988 , Richmond an d Fletche r 1971 .

*\A\Cp. 1

-93 - Not e tha talthoug h glas s i s reported t o shatte r ata n overpressur

e leve l o f 0. 5 ps i (se e ExhibitC-2) , there i s evidenc e tha

thuma n injui y from flying glas s i s unlikely a tthi s level . Lee s (1980 ) dte s a reportstatin g tha t ris k o f injur y from fryin

g window glas s i s negligibl e for a n explosio n tha

tgive s a pea

k overpressur

e o f 0. 6 ps i o r less . Lee s als o dte s a repor tgiving th e ski n laceratio n threshol d for flying glas s as 1- 2 ps i an d th e seriou s woun

d threshol d as 2- 3 ps i (se e ExhibitC-l) . Fletcher , Richmond , an d Yelverto n (1980 ) carrie d ou texperiment

s o n th e effect

s o n shee p an

d dog s o f glas s fragments from window s shattere d b

y various blas toverpressures . Thei r result s (briefl y dte d i n ExhibitC-l ) appea r t o agre e reasonabl

y wel l wit h th e dat a reporte d b y Lees . Thei r dat

a indicat e tha tth e threshol d for injur

y fro m flyin g glas s i s about0. 6 psi . Multipl e injuries from ski n penetratio n (i.e. , te n o r more ) ma y occu r for bar

e ski n atoverpressures o f 1. 5 ps i o r higher . Flying glas s ma y penetrat

e th e body-wal

l at5. 8 ps i o r highe r if

th e ski n i s bare . Th e author s poin tou ttha

tth e ski n an

d body-wal

l thicknes s o f

men an d shee p ar

e approximatel

y th e sam e (Fletcher , Richmond , an

d Yelverto n 1980) ; therefore , th e dat a reported shoul d b e roughl y applicabl e t o humans . C.L2 Distanc e Determinatio n for DifferentOverpressure s T o determine th e effe a o n distance o f modellin g t o differen

toverpressure

s for vapo r clou d explosion , th e WHAZA N mode

l wa s ru n fo r severa l differen toverpressures fo

r vapo r dou d explosion s o f ethylen e an

d propylene . Exhibi

tC- 6 shows explosio n overpressur e versu s consequenc e distance for 100,00 0 pound release s o f

ethylen e an

d propylene . Th e curve

s are no tlinear , a relatively small change i n overpressur e a t th e lowe r en

d o f th e scal e result

s i n a relativel

y large change i n th e consequenc e distance , whil e a relatively smal l change i n overpressur e a tth e uppe

r end o f th e scal e result

s i n relatively smal

l change i n consequenc e distance . However , increasin g th e overpressur

e atth e uppe

r en d o f th e overpressur

e scal e appear s t o hav e a muc h smalle r effe a o n th e consequenc e distance . C2 Flammabilit

y limit s A s note d i n th e tex t(Sectio n 5.3.2.2) , th e lowe r flammable limi t(LFL ) o f a vapo r o r gas i s th e minimu m concentratio n i n ai

r tha twil l ignite an

d propagat

e flame. Usin g 5 0 percen to f th e LFL t o estimat

e consequence distances fo

r vapo r clou d fire

s account s for variabilit

y withi n th e cloud from it s edg e t o its cente r an d inaccurade s i n dispersio n modelling . T o determine th e effe a o f usin g differen

tconcentration s t o estimate th e consequenc e distance for vapo r clou d fires , tw

o representative chemicals , ethylen e an d propylene , were modelle d usin g WHAZA N a t 10,000 pound

s an d 100,000 pounds . Moderat e meteorology (win

d spee d 3. 0 meter

s pe r secon d an

d atmospheri c stabilit

y D ) wa s assumed . Th e model wa s ru n for thre e concentrations , at50 % o f th e lowe r flammable limi ta

tth e lowe r flammable limi tan d at200 % o f

th e lower flammable limi tTh e result s o f modellin g ar

e show n graphicall

y i n Exhibi

tC-7 . Th e result

s curve s for bot h quantitie s an

d bot h chemical s modelle d ar

e basicall y simila r i n shap e bu

to f differin g magnitudes . Th e result s curve s clearl y ar e no t linear : th e chang

e i n magnitude between th e consequenc e distance obtained a t50 % o f th e lowe r flammabile limi tan

d thata tth e lowe r flammable limi ti s clearl y greate r tha

n th e chang e betwee n th e lowe r flammable limi tan d 200 % o f

th e lower flammable limi tfor al l fou r curves .



## ib" !Exhibi tC- 6 HAZAR D CRITERI A COMPARISO N FO R VAPO R CLOU D EXPLOSION S FO R INSTANTANEOU S RELEASE S O F 100,00 0 POUND S

175 0

150 0

125 0 ^** ( 0 o o E g 100 0 c t o n O 75 0

50 0

25 0 Ethylen e

Propylen e

*

4 5 6 Overpressur e (psi ) 8 9 1 0

h oExhibitC- 7 HAZAR D CRITERI

A COMPARISO

N FO R VAPO R CLOU D FIRE S FO R EVAPORATIN

G POOLS FRO

M INSTANTANEOU

S RELEASES , MODERAT E METEOROLOG

Y (Win d spee d 3. 0 meter

s pe r second , atmospheric stabilit y clas s D )



## 150 0

125 0

100 0

( D O C D in 

# 750 -
500 -

25 0



## 0 • Ethylen e (100,00 0 lbs. ) A Propylen e (100.00 0 lbs. )
* Ethylen e (10,00 0 lbs. ) O Propylen e (10.00 0 Iba. )

v O xj\



# 1 50 % LF L LF L 2LF L

-8 > 

# Concentratio n

C OP. 4

-96 - C 3 HeatRadiatio n C3. 1 Hea

tRadiatio n Level s Causin g Deat h an d Injur

y Huma n injur y o r fatalit

y from hea

tradiation from fires i s likel y t o occu r as a resul to f dire a exposure t o a fir e rather than a s a resul to f propert y damag e cause d b

y a fire . Th e exten to f

th e injur y cause d b y hea t radiation depend s bot

h o n th e hea

tlevel an d th e tim e o f

exposure . Exhibi

tC- 8 present

s heatradiatio n level s an d exposur e time s require

d t o produc

e variou s huma

n effect s o r injuries . Ther

e ar e fe w dat a o n fatalitie s fro

m hea tradiation ; th e fatalit

y dat a show n i n ExhibitC- 8 hav

e bee n calculate d o r estimated . Bot h th e WHAZA N (1988 ) an d Muda n (1984 ) fatalit

y dat a appea r t o b e based o n dat

a o n th e relatio n betwee n therma

l radiatio n intensit

y an d bur n injur y fo r nuclear explosion s a tdifferen tyield s (Eisenber g e t a L 1975 , as dte d b

y Muda n 1984) . According t o Muda n (1984) , exposur

e time s for nuclear explosion s are typicall y ver y shor tan d interpretatio n o f

th e dat a i s "somewha

tsubjective. " I n a revie w o f fir e hazard s b y Takat a i n 197 0 for th e Arme

d Services Explosive Safet y Board , estimate s are presente d o f

critica l radiantexposur

e necessar y t o ignite o r damag

e severa l type s o f targets , includin g people . A s reported i n Vo L I o f th e CPI A "Hazard

s o f Rockets an

d Propellants, " minimu

m critica l exposure s necessar

y t o ignite o r damag

e peopl e rang

e from 94. 6 kW/m 2 fo r a 10-second exposure tim e t o 35. 1 kW/m2 for a 60-secon d exposur e an d 27. 8 kW/m2 fo

r a 190-secon

d exposure . Th e WHAZA N manua

l include s a tabl e fo r fatalit y base d upo n exposur

e t o hea tExhibitC- 9 present s th e lethalit y o f hea tflux as presented i n th e manual . Th e exposur

e time s give

n fo r th e fatalit

y level s ar

e calculated from a Probi

tequatio n (indicatin g statistica l probabilit y base d o n deviation s from th e mea n o f norma l distribution) , as follows : Probi t= -14. 9 + 2.5 6 log

g ( tx Q 4/ 3 x IO"

4 ) wher e Q i s i n watt

s per squar

e meter an

d ti s i n second s Th e WHAZA N model use s radiation level s o f 12. 5 t o 37. 5 kW/m

2 i n it s output , based o n th e likelihoo d tha tpeopl e woul d b e abl e t o "shelter " from th e fir e withi n 3 0 second s t o on e minute . Fo r thi s perio d o f time , th e probabilit

y o f fatalit y range s from 1 percenta

t12.5 kW/m

2 fo r 3 0 second s t o 9 9 percentat37. 5 fo r 5 0 second s (se e ExhibitC-9) . Muda n (1984 ) estimate d a slightly lower fatalit y threshol d o f

1 0 kW/m 2 fo r a 40-secon d exposure time . Muda n estimated thi s leve l from th e dat a o f Eisenberg e tal (1975 , as dte d b y Muda n 1984) . A plo to f therma l radiation versus tim e fo

r injuries an

d fatalitie s shows that1 percen tfatalitie s ma

y occu r at1 0 kW/m 2 ata tim e o f

4 0 seconds . Th e 1 0 kW/m 3 radiation leve l suggested b y Mudan, whic

h i s use d i n th e ARCHI E mode

l t o determine th e zon e fo r fatalitie s from poo l fires , agree s quit e wel l wit h th e 12. 5 kW/m 2 level . Nazari o (1988 ) indicate s thatal l personne l shoul d b e evacuated from area s wher e th e radian

thea ti s likel y t o excee d one-half

o f th e threshol d valu e for secon d degre e burn s t o bar e ski n (5,00 0 Btu/hr-ft 2 , o r 1 6 kW/m 2 , fo r a n exposur e o f abou t5 seconds) .



## ^ 0P. 5

-97 - EXHIB_TC- 8 HUMAN INJUR Y CRITERI A (Therma l Radiatio n Effect s o n Bar e Skin )

Therma l Radiatio n fkW/m«

_ 1.7 5

6. 4

1 0 12_ 5

37. 5 Tim e o f Exposure (Seconds' ) 6 0

2 7 9 2 1 5 1 3 4 0

8 2 0 4 0 3 0 8 0 20 0 8 2 0 5 0 Injur y o r Effect Pai n threshol d reache d

Sever e pai n Second degre e bur n Pai n threshol d reache d "Unbearable " pai n Second degre e bur n (injur y threshold ) Pai n Uireshold reache d Second degre e bu m Fatalit y threshol d 1 % fatalit y 50 % fatalit

y 99 % fatalit

y 1 % fatalit y 50 % fatalit

y 99 % fatalit

y Sourc e

WHAZA N 198 8 Buettne r 195 1 Hard y e t a L 195 3 Stoll an d Green e 195 9 Bigelow e t

a L 194 5 HCHA P 198 9

WHAZA N 198 8 Mudan 198 4 Mudan 198 4

WHAZA N 198 8 WHAZA N 198 8 Muda n 198 4 WHAZA N 198 8 WHAZA N 198 8 WHAZA N 198 8 WHAZA N 198 8 WHAZA N 198 8 WHAZA N 198 8



# ruP. 6

Therma l Radiatio n (kW/m2 ) 1. 6 4. 0 12 ^ 37. 5 -98 - ExhibitC- 9 FATALIT Y FRO M HEA T EXPOSUR

E Second s 1 % 50 0 15 0 3 0 8 exposur

e for % fatalit

y 50 % 130 0 37 0 8 0 2 0 99 %

320 0 93 0 20 0 5 0

Reference : WHAZA N Handbook (1988 )

t 

## "| VP. 7

-99 - C32 Distanc e Determinatio n fo r DifferentHea tRadiatio n Level s Modellin g wa

s carrie d ou tusing th e WHAZA N model t o determine th e effe a o f heatradiation leve l o n consequenc e distance s fo r BLEVE s an d poo l fires . C3.2. 1 BLEVE

S Fo r BLEVEs , ethylen e an d propylen

e wer e modelle d a t10,000 pound s an d 100,00 0 pounds . Th e mode l wa s ru n for thre e hea

tflux consequence levels , 4 kW/m 2 ,12. 5 kW/m 2 , an d 37. 5 kW/m

2
. Th e relationshi p betwee n th e consequenc e distanc e result s for ethylen e an

d propylene an

d othe r hydrocarbo

n result s fo r BLEVE s ca

n b e see n b

y examinin

g ExhibitC-10 . Th e result s curve s fo r bot h quantitie s an d both hydrocarbon

s modelle d ar

e basicall y simila r i n shap e bu

to f differin g magnitudes . Th e result s curves dearl y are no tlinear : th e chang e i n magnitude between th e consequence distance obtaine d a t4 kW/m2 an d thata t12-5 kW/m 2 i s dearl y greate

r tha n th e change between 12. 5 kW/m 2 an d 37. 5 kW/m2 fo r al l four curves . Result s for othe r hydrocarbon s studie d are approximatel y th e sam e a s th e result

s fo r propylene . C322 Pool Fire s Fo r poo l fires, ethylen e an d propylen

e wer e modelle d a

t10,00 0 pound s an

d 100,000 pounds . Th e WHAZA N model wa

s ru n fo r thre e hea

tflux consequence levels , 1.6 kW/m 2 , 4 kW/m 2 , an d 12. 5 kW/m2
. Modellin g result

s ar e presented i n Exhibi

tC-ll . Th e result

s curve s for bot h quantitie s an

d bot h chemical s modelle d are basicall

y similar i n shap e bu

to f onl y slightly differin

g magnitudes . Th e result s curves clearly are no tlinear : th e chang e i n magnitud

e between th e consequence distance obtaine d at1.6 kW/m2 an d tha t at4 kW/m2 i s dearl y greate r tha n th e change between 4 kW/m 2 an d 12. 5 kW/m

2 fo r al l fou r curves . Result s for othe r hydrocarbon s studied ar

e approximatel

y th e same a

s th e result

s fo r ethylen e an

d propylene .



# \" BExhibitC-1 0 HAZAR D CRITERI

A COMPARISO

N FO R BLEVES , INSTANTANEOU

S RELEASE

S



## O 

# c a +-> 

## m

S <I___JJ * 

## Q 80 0
70 0 H
600 - 500 - 400 - 300 - 200 - 100 - 0 0 

# £ • Ethylen e (100.00 0 lbs. ) A Propylen e (100.00 0 lbs. ) * Ethylen e (10.00 0 Iba. ) O Propylen e (10.00 0 lbs. )

12. 5 37. 5 

# BLEV E Hea t Flu x (kW/m2 )

T l 0 0Exhibi tC-l l HAZARD CRITERI A COMPARISO N FO R POO L FIRES ,

INSTANTANEOU S RELEASE S



### C D <_ > 

## C 

# o 60 0

50 0 

## -

40 0 

## -

30 0 

## -

^ 20 0 

## -

10 0 

## -

0

_ 3 

# Poolfir e Hea t Flu x (kW/m2 )

toP.1 0

-102 - CA Reference s AIChE . 1987 . America

n Institut e o f Chemica l Engineers . Method s for Calculatio n o f Fire an d Explosion s Hazards . Ne w York : AIChE , Brasie , W. , Simpson , D . 1968 . "Guideline s Fo r Estimating Damage Explosion, " AICH E Symposiu

m o n Los s Preventio n i n th e Proces s Industries , Februar y 18-23,1968 . CPI A 1984 . Hazard

s o f Chemica l Rocket s an d Propellants , Volum e I , Safety , Health , an d th e Environmen tCPI

A Publicatio n 394 , September 1984 . Laurel , MD : John s Hopkin s University . Eichler , T. , Napadensky , H . 1977 . "Acddenta l Vapo r Phas e Explosion s o n Transportation Route s Nea r Nuclea r Plants, " H

T Researc h Institute , Prepare

d for Argonne Nationa

l Laboratory. Apri

l 1977 . Eisenberg R A e tal . 1975 . Vulnerabilit y Model . A Simulatio n Syste m fo r Assessin g Damage Resultin g from Marin

e Spills . NTI S AD-A015-245 . Springfield , V A Fletche r E.R. , Richmond D.R. , Yelverto n J.T . 1980 (Ma y 30) . "Glas

s Fragmen

tHazar d from Window

s Broken b y Airblast " Washington , D.C:Defens e Nuclea r Agency . ReportNumbe r DN A 5593T . Grelecki , C "Fundamental s o f Fire an d Explosio n Hazard

s Evaluation, " C Grelecki , Hazard s Researc h Corp. , AICH E Toda

y Series . HCHAP . 1989 . Handbook o f Chemica l Hazar d Analysis Procedures . Federa l Emergenc

y Managemen

t Agency , U.S . Departmen

to f Transportation , U.S . Environmenta l Protectio n Agency . Kokinaki s W. , Rudolp h R. 1982 . A n Assessmento f th e Cunen tState-of-the-Ar to f Incapadtatio n b

y Ai r Blas tMinute s o f

th e 20t h Explosives Safet

y Seminar

, August1982 . Lees , F.P . 1980 . Los s Preventio n i n th e Proces s Industries , Vol . 1 . London : Butterworths . McRae , T . 1984 . "Th

e Effect s o f Larg e Scal e LNG/Wate

r RPT Explosions, " McRae , T.G. , etal. , Lawrenc e Livermor e Nationa l Laboratory. April 27,1984 . Muda n K.S . 1984 . Therma

l Radiatio n Hazard

s from Hydrocarbo

n Poo l Fires . Prog . Energy. Combus t Sd . 1984 , Vol . 10 . Grea

tBritain : Pergamo

n Press Ltd . Nazari o N.N . 1988 . Preventing o r Survivin g Explosions . Chemica

l Engineering , August15,1988 . NFP A "Fir

e Protectio n Handbook, " 16t h edition , Nationa

l Fire Protectio n Associatio n (NFPA) . Richmond , D . 1968 . "Th e Relationshi p Between Seleae d Blast-Wav e Parameter

s an d th e Respons e o f Mammal s Expose d t o Ai r Blast. " Richmon d DR , Damon E.G. , Fletche r E.R. , Bowe n I.G. , Whit

e CS. , Ann . N.Y . Acad . ScL, 1968 . Richmon d D.R. , Fletche r E.R . 1971 . BlastCriteri a fo r Personne

l i n Relatio n t o Quantity-Distance . Minute s o f

th e 13t h ASES B Seminar, 401-419 . U.S . Ai r Forc e 1983 . "Explosive s Safet y Standards, " A F Regulatio n 127-100 , 2 0 Ma y 1983 . U.S . DO T 1988 . "Hazar

d Analysi s o f

Commerda

l Spac e Transportation, " Offic

e o f Commerda

l Space Transportation Licensin g Program s Division , U.S . Departmen to f Transportation . Ma

y 1988 . WHAZAN . 1988 . WHAZA N Use r Guide . Technic a Internationa

l Ltd . Wiekema , B . J. 1984 . "Vapo r Clou d Explosions - A n Analysis Base d o n Acddents, " Journa

l o f Hazardou

s Materials , 8 (1984) .

^P.1 1

APPENDI X D COMPARISO N O F RESULT S O F MODELLIN G B Y DIFFEREN T METHOD S AN D RESULT S O F VARYIN G RELEAS E SCENARIO S AN D METEOROLOGICA L CONDITION S



# i n-104 - Appendi x D . Comparison o f

Result s o f

Modellin g b

y Differen tMethod s an

d Result s o f

Varyin g Releas e Scenario s an d Meteorolog y
D. l Vapor Clou

d Explosio n Result s ExhibitD- 1 present

s th e result

s o f modellin g usin g severa

l method s for vapor clou d explosion s based o n 0. 5 ps i overpressure . Thi s exhibi tshows th e maximu m distance a

twhic h th e model s indicat

e tha tth e chose n overpressur

e woul d b e reached . Fo r release s o f 100,00 0 pound s o f

gases , distance s o f

32 6 t o 1,16

5 meters were calculated . Th e distances obtaine d fro m WHAZAN , th e Yello w Book , an d ARCHI E ateac

h overpressur

e leve l agree quit e wel l wit

h each other , although th e WHAZA N an d Yello w Boo k distance s fo r vapo r clou d explosion s for ethylen e an

d propane are significantl y lowe r tha

n th e distance s obtained from ARCHIE . Thes e tw o gase s ar e assume d t o b e store d atreduce

d temperatures . Th e WHAZA N an d Yello w Boo k vapo r clou d explosio n calculation s ar

e based o n th e quantit

y o f gas immediatel

y flashed into vapor o n release , an d thi s quantit y depend s o n th e differenc e betwee n th e temperatur e o f th e released ga

s an d it s boilin g poin tA s ethylen e an

d propane ar

e assume d t o b e store d a

ttemperatures no tfa

r above thei r boilin g points , th e fractio n calculated t o b e immediately flashed int o vapo r (i.e. , th e quantit y tha tma y b e involved i n a vapo r clou d explosion ) i s relatively small . ARCHIE , o n th e othe r hand , assumes tha tal l th e materia

l i n a containe r o f

pressurize

d ga s i s release d t o th e air as a gas-aeroso l mixtur e unles s th e storag e temperatur e i s mor e tha n 10° C belo w th e boilin g poin to f th e gas . Fo r ethylen e an d propane , th e assume

d storage temperature , thoug

h belo w ambien

ttemperature , i s greate r tha n th e boilin g point ; therefore , ARCHIE , unlike WHAZA N an

d th e Yello w Book , doe s no tyiel d consequenc e distances fo r thes e two gase s tha

tar e significantl

y lower tha

n thos e for th e othe r gases . I f th e storage temperatur

e i s mor e tha n 10° C belo w th e boilin g point , ARCHIE assumes th e materia l i s release d as a liquid , and , therefore , n o vapor dou d explosio n result

s ar e obtained . ARCHIE produce

d vapo r clou d explosio n result s fo r th e liquid s modelled ; however, a disclaime r wa s provide d i n th e accompanyin

g manua l an d o n th e outpu tresult

s pointin g ou ttha

t"inddent

s involving tank s tha tar e designed t o operat

e atatmospheric pressur

e ar e ver y rare. " A n additiona

l disclaimer stated tha tclouds o r plumes containin g les s tha n 1,00 0 pound s o f

vapor o r ga

s ar e ver y unlikel y t o explod e when completely unconfined ; modellin g indicated tha tfor heptane , toluene , an d p-xylene , ther e woul d b e les s tha n 1,00 0 pounds o f

vapor released . Becaus e o f thes e disclaimers , th e ARCHI E vapor clou d explosio n result s fo r th e liquid s modelle d ar

e no tinclude

d i n ExhibitD-1 . D. 2 Vapor Qou d Fire Result s ExhibitD- 1 includes vapo r clou d fire result s calculated b

y fiv e method s fo

r release s o f

100,00 0 pounds . Th e distances give

n are downwin

d distances for dispersio n t o a concentratio n equa l t o 5 0 percento f

th e LFL . For th e Yello w Book , result s fo r gases wer

e calculate d base

d o n bot h th e quantit

y o f ga s immediatel

y flashed int o vapo r upo n releas e an d o n th e remainin

g liquefied ga

s evaporating from a poo l afte r flashing; not e tha

tth e distance s obtaine d usin g th e quantit y flashed into vapo r are significantl y large r tha n thos e calculated usin g th e evaporating pool , excep ti n th e case s o f th e two gase s assumed't

o b e store d a treduce d temperatures . Fo r thes e tw o gases , ethylen e an

d propane , th e distances calculate d based o n th e evaporating poo l ar

e greate r than th e distance s based o n th e quantit y flashed . Results from th e AICh E cours e materia

l fo r gase s ar e based onl y o n th e quantit y flashed, as recommended . Th e distance s calculated fo

r ethylen e an

d propane , th e gases assume d store d a

treduce d temperatures , ar

e considerabl

y lower tha n th e distance s for th e tw o gase s assume

d store d a

tambien ttemperature . Distance s obtaine d fo r gase s using th e Green Boo k methodology ar e generall y lowe r tha

n thos e foun

d b y th e othe r methods , probabl y becaus e th e Green Boo k recommends assumin g total releas e o f

th e ga s ove r a te n minut

e period , whil e th e othe r method s assume a n instantaneou s release . Th e distances calculated usin g th e Green Boo k



# n< 8ExhibitD- 1 RESULTS OF MODELLIN G B Y AL L METHODS WHAZA N Modellin g Result s fo r Instantaneou s Releases , Moderat e an d WorstCas e Meteorology , an d Prolonged Releases , Moderat e Meteorolog

y (100,00 0 pounds )

Chemica l Ethylen e Propylen e Propan e Butan e Ethylen e Oxid e Ethy l Chlorid e Acetaldehyd e Pentan e Aceton e Gasolin e Hexan e Trichloroethylen e Heptan e Toluen e Aceti c Aci d p-Xylen e Benzaldehyd e Dimethy l Sulfoxid e Boilin g Poin t (K ) 17 1 22 7 22 9 27 5 28 2 28 6 29 3 31 3 32 9 33 2 34 5 36 0 37 5 38 3 39 1 41 0 45 2 46 2 INSTANTANEOU S RELEAS E

MODERAT E METEOROLOG Y Distanc e (meters ) VC E VC F BLEV E (0. 5 psi ) (50 X LFL ) <12.5kW/m2 )

45 7 139 0 38 8 112 1 70 6 28 7 39 2 74 7 27 8 76 6 46 0 26 9 44 3 33 8 20 6 26 8 26 2 17 8 13 0 45 1 20 0 * * 34 1 26 9 • • 21 4 * * * * 33 8 * * • * 23 3 • * # * j j * * * • 17 3 * • * • 15 4 * • * * 9 8 * * * * 11 0 * * * * 3 0 * * * * 4 1 • « Poo l Fir e (12.5kw/m2 ) 18 1 16 0 18 3 17 6 10 9 9 7 10 7 18 2 11 6 17 5 17 4 * * 16 8 15 3 * * 15 2 10 9 8 6 VC

E INSTANTANEOU

S RELEAS E WORS T CAS E METEOROLOG Y Distanc e (meters ) VC F BLEV

E (0. 5 psi ) (SO

X LFL ) (12.5kw.m2 )

45 7 112 1 39 2 76 6 * * * * * * # # • * * * * * * * • • * * Poo l Fir e (12.5kU/m2 ) 635 0 38 8 290 0 28 7 310 0 27 8 179 0 26 9 • * » * • * 128 0 26 9 * * 127 0 * * 84 2 * • • • 60 4 * * 53 5 * • • * 37 4 * * • • • * 181 16 0 18 3 17 6 • * * 18 2 • 17 5 17 4 » 16 8 15 3 * 15 2 • • VC

F (50 X LFL )

7 9 1 8 7 3 2 0 * « * 2 1 • 6 4 5 6 « 5 7 6 7 * 6 5 • * PROLONGE

D RELEAS E MODERAT E METEOROLOG Y Distanc e (meters ) BLEV E Poo l (12.5lcU/m2 ) Fir e

(12.5kv/n*2)(1 2 38 8 1 7 28 7 1 5 27 8 1 7 26 9 9 • • • * • • 26 9 2 3 • • * * 1 6 • • 1 5 • • * • 1 5 * « 1 6 • • * * 1 6 • • • * Je t Fi n .5 M * » 4 2 • • 2 1 • • * * * • * • • _ • • _ # * • * * • •
* Analysi s wa s no t carrie d ou t * * N o result s wer e obtaine d fro m analysis , o r result s wer e no t Included , base d o n evaluation . VC E = Vapo r Clou d Explosio n VC F « Vapo r Clou d Fir e

n . Modelling Results Usin g Othe r Method s for Instantaneou s Releases , Moderat e Meteorolog

y (100,00 0 pounds ) 

## 8

Chemica l

Ethylen e Propylen e Propan e Butan e Pentan e Gasolin e Hexan e Heptan e Toluen e p-Xylen e Boilin g

Poin t (K >
17 1 22 7 22 9 27 5 31 3 33 2 34 5 37 5 38 3 41 0 ARCHI E Result s

Distanc e (meters ) VC E VC F (0. 5 psi ) (50 X LFL )

86 7 77 0 68 2 75 1 68 3 73 3 68 0 71 2 • • 45 3 » M 7 * * 16 0 « * 11 2 * * 9 7 * * 0 BLEVE

28 5 28 5 28 5 28 5 * # * * * * « » * * * « Poo l

Fir e (10kV/rri_

>

* * * * * * * * 15 1 13 7 15 1 15 3 15 0 144 VC

E (0. 5 psi )

41 5 93 2 32 6 63 5 * * * « * * * * * » * * Yellow

Boo k Result s Distanc e (meters ) VC F (Gases ) VC F (All ) Flas hPoo l Fractio n Evaporatio n (50 X LFL ) (50 % LFL ) 33 0 92 2 86 2 55 4 26 1 58 6 54 7 24 2 • * 23 9 * * 21 6 * * 11 5 " 6 0 • * 4 2 * * 2 2 Poo l Fir e (12.5kU.m2 )

13 4 11 2 13 7 12 0 12 0 10 7 11 2 10 6 8 6 8 6 AICh E Manua l Result s

Distanc e (meters ) VC F (Gases ) VC F (Liquids ) Flas hPoo l Poo l Fir e Fractio n Evaporatio n (12.5k_/m2 ) (SO X LFL ) (50 X LFL ) 45 2 • • 116 5 * • 35 5 * « 72 0 * * * * 18 7 * * 17 0 * * 9 5 * * 5 3 * « 3 8 * * 2 1 29 9 18 8 22 5 19 0 22 1 21 3 20 6 20 2 16 9 16 6 Gree n Boo k

Distanc e VC F (SO X LFL )

37 1 35 0 33 2 31 0 16 5 16 3 8 6 • 5 0 • 4 4 • 2 8 •

* Analysi s wa s no t carrie d out . * * N o result s wer e obtaine d fro m VC E « Vapo r Clou d Explosio n VC F » Vapo r Clou d Fir e analysis , o r result s wer e no t Included , base d o n evaluation . • Metho d I s no t vali d fo r distance s les s tha n 10 0 meters .



### ^ 3 

### _Z 2 T JP.1 4

-106 - method , whid i doe s no ttake storag e temperatur e into accoun tare higher tha n othe r result

s only i n th e case s o f th e Yello w Boo k result

s fo r th e flashed fraction o f ethylen e an

d propane (th e gase s assumed store d a treduce d temperatures) . Results for chemical s tha tar e liquid s atambien

ttemperature

s ar e based o n evaporatin

g pool s for al l th e model s (se e Appendi

x B for details) . Distance s t o a concentratio n equa l t o 5 0 percen

to f th e LFL for vapo r dou d fires rang

e from 26 1 t o 1,390 meter s for gases ; distances ar

e generall y smaller for liquids , although significan

tdistance s resul tfo

r volatil e liquid s (e.g. , distances calculated b y th e variou s method s range from 16

5 t o 45 3 meter

s fo r pentane) . Distance s obtained using th e Green Boo k dispersio n modellin g calculation s are no tvali d for les s than 100 meters ; therefore , th e Green Boo k result s for four relatively non-volatil e liquid s shoul d b e disregarded . I ti s possibl e tha

tdistance s les s tha

n 100 meter

s obtaine d from som e o f

th e othe r method s ma

y als o b e invalid , as similar method s appea r t o b e use d i n th e calculations . D3 BLEV

E Result s ExhibitD- 1 present

s th e result

s obtaine d usin g WHAZA N an d ARCHIE t o mode

l BLEVEs for 100,00 0 pound releases . WHAZA N result s ar e show n for a hea

tradiation leve l o f

12. 5 kW/m

2 fo r WHAZAN . Th e distanc e reported as th e "fatalit y distance " o n th e ARCHIE outputresult s i s presente

d i n thi s exhibi t BLEVE s ar

e no tmodelle d i n ARCHIE ; however , sinc e fireballs ar e generall y associated wit

h BLEVEs , thes e result

s from th e ARCHIE mode l ar e presente d i n Exhibi

tD- 1 for comparison t o WHAZA N BLEV E results . Th e othe r model s used for consequence analysi s di d no tinclud e methods for analyzin g BLEVEs . ARCHI E result

s ar e base d o n fireball siz e an

d hea tradiation (se e Appendi

x C , Sectio n ALIO) . According t o th e ARCHI E manual , th e fatalit y leve l corresponds t o a hea tflux i n exces s o f

160 kilojoule s pe r squar e meter (kJ/m2 ) . Usin g th e firebal l duration o f

1 5 second s t o conver

tth e hea tradiation leve l from kJ/m2 t o kW/m 2 indicate s tha

tth e ARCHI E fatalit

y leve l i s about1 1 kW/m 2 , whic h i s vei y dos e t o 12. 5 kW/m

2 , used b y WHAZAN . Note , however, tha tWHAZA N give s a BLEVE duratio n o f 3 6 second s whil e ARCHIE give s a duration o f 15 second s fo

r a 100,000 poun

d release . Th e ARCHIE model give s a fatalit y distance o f

28 5 meter

s fo r al l th e chemicals modelled ; th e lac k o f variatio n b

y chemica l i s probabl

y du e t o th e fa a that, accordin g t o th e ARCHIE manual, ARCHIE assumes tha

tth e chemica

l modelle d i s propane o r ha s simila r charaaeristics . WHAZAN consequenc e distance s range from 17

8 meter s t o 387 meter

s for a hea

tradiation leve l o f

12.5 kW/m

2
. D. 4 Pool Fire Results Result s o f

modellin g usin g differen

tmethod s for poo l fires, showin g th e maximu

m distanc e atwhic h a hea t radiatio n leve l o f

12. 5 kW/m

2 (1 0 kW/m

2 for ARCHIE ) i s reached , ar e presented i n Exhibi

tD-1 . Th e WHAZA N mode

l indicated tha

tth e poo l fires o f

th e chemicals modelle d woul d las t6 0 second s o r more ; a s state d i n th e WHAZA N manual , i tmigh tb e possibl e t o "shelter " from th e fire within about3 0 second s t o on e minute . Difference s betwee n chemical s modelle d b y eac h method ar

e relativel y small . Th e distances calculate d b y differen tmethod s are i n reasonabl y goo d agreemen

twit h eac h other . Th e calculations base d o n th e AIChE-sponsored materials gav e th e greates tdistances (16 6 t o 29 9 meters) , whil e th e Yello w Boo k metho d gave th e smalles t(8 6 t o 134 meters) . Th e ARCHIE mode l doe s no tgive poo l fire result s for gases . Th e othe r model s allo w th e calculatio n o f result s fo r gases ; th e result

s for gase s diffe r littl e from th e result s for liquids . Th e distance s foun d fo r poo l fires fo

r 100,000 poun

d release s o f

gase s fo r a heat radiation leve l o f

12. 5 kW/m

2 ar e smaller tha

n th e distances for vapor clou d explosions fo r th e same quantit y modelle d a

t3. 0 psi o r lower , excep tfor gase s assume d store d atreduce

d temperatures . Vapo r clou d fire result

s (fo r 5 0 percen

to f th e LFL ) an

d BLEV E result s (for 12. 5 kW/m 2 ) fo r gase s ar e large r tha n th e poo l fire results . Fo r relatively volatil e liquids (e.g. , pentane) , vapo r cloud fir e distance s ar

e generall y greater tha

n poo l fire distances ; fo

r les s volatil e liquids , distances calculated b y mos to f th e method s ar

e greater fo

r poo l fires. 

# \Q) , 0P.1 5

J J -107 - D. 5 Je tFire Result s Je tfire results , whic

h are , b y definition , prolonge d releases , were obtaine d onl y for propylene an d butane , th e tw o gase s assumed t o b e liquefie d under pressure . Fo r je tfires , th e releas e wa s assume d t o tak e plac e from a 1. 5 inc h hol e i n a tan

k 1 2 fee ti n diameter . Results ar e show n for 100,00 0 pound release s i n ExhibitD- 1 for a heatflux leve l o f 12 3 kW/m

2
. Je tfires o f

propylene an

d butan e unde

r thes e condition s gave distances tha

tar e smalle r tha

n an y o f th e distance s for an

y othe r acdden ttyp e resultin g from instantaneou s releases . Distance s for je tfires ar e somewha

tgreater, however , tha

n for vapo r clou d fires o r poo l fires resultin g from prolonge d release s unde r th e sam e conditions . D. 6 Instantaneou s Releas e Compare d t o Prolonged Releas e Te n hydrocarbon

s studied were modelle d usin g th e prolonge d releas e scenari o i n th e WHAZA N linke d model for comparison wit h th e modellin g result

s for instantaneous release . Th e WHAZA N linke d model (prolonge d release ) wa

s ru n fo r 100,00 0 pound s o f

eac h chemica l assumin g th e sam e meteorological condition s (3. 0 meter

s per secon d win

d spee d an

d D win d stability) , an

d storag e condition s as for th e instantaneou s release . T o simulat e a prolonge d release , a 1. 5 inc h hol e i n a 1 2 foo tdiameter tan k wa s assumed . Th e averag

e evaporation rate for th e pool , as determine d i n th e linke d model , wa s the n use d t o ru n th e WHAZA N stand-alone model for buoyan tplum e dispersion (se e Appendi x B. 1 fo r more information) . ExhibitD- 1 shows result

s o f WHAZA N modellin g for prolonge d release s o f te n chemicals , where releas e wa s assume d t o take plac e from 1 3 inc h diameter hole s i n 1 2 foo tdiameter tanks . Distance s t o 5 0 percen to f th e LFL fo

r vapor clou d fires ar

e muc h smaller (1 8 t o 7 9 meters ) tha n fo r instantaneou s releases . Fo r poo l fires , prolonged release s als o resulti n muc h smaller consequence distance s tha n instantaneou s releases . A s wa

s th e cas e fo

r instantaneou s releases , th e consequence distance varies littl e from chemica l t o chemical . Th e magnitud e o f th e result

s curv e i s muc h smaller fo

r prolonge d release s tha

n fo r instantaneou s releases , an d al l o f th e prolonged releas e consequence distance s ar e les s tha n 2 5 meters . WHAZA N di

d no tproduc

e vapor clou d explosio n result s fo r prolonged releases . A s show n i n ExhibitD 1 , WHAZA N produce

d BLEVE result

s fo r prolonge d release s tha tar e identica l t o th e result

s for instantaneou s releases . I

ti s no tclea

r wha tthes e result

s mean , sinc e BLEVE s see m t o b e instantaneou s release s b y definitio n (se e Sectio n 7.13) . D. 7 Moderat

e Meteorolog

y Compare

d t o WorstCas e Meteorolog y Te n hydrocarbon

s were modelle d usin

g WHAZA N t o determine th e effe a o n consequenc e distance s o f usin g wors tcas e meteorology rather tha n moderat

e meteorology . Th e WHAZA N linke d model (instantaneou s release ) wa s ru n fo r 100,000 pound s o f

eac h chemica l usin g th e same storage temperatures an d pressure

s as used wit

h moderat

e meteorology . Wors

tcas e meteorologica

l condition s (1. 5 meter

s pe r secon d win

d spee d an

d F win d stability ) were use d rather tha n moderat

e meteorologica

l condition s (3. 0 meter s per secon d win

d spee d an

d D win d stability) . Th e averag

e evaporatio n rat

e for th e pool , a s determined i n th e linked model , wa s use d t o ru n th e WHAZA N stand-alon e model fo r buoyan tplum e dispersion . Variou s othe r defaul tvalue s were used i n th e model ; thes e value s are summarize d i n Appendix E . ExhibitD- 1 include s vapor cloud fir e result s from WHAZA N for ten chemical s usin g wors tcas e meteorologica

l condition s o f

win d spee d o f

1. 5 meter s per second an

d F atmospheri c stability . Th e WHAZA N result

s appea r t o b e strongl

y dependento n th e meteorologica l assumption s made , wit

h distances determined using worstcas e meteorology bein g muc h greate r tha n thos e resultin g from modellin g using moderat

e meteorology . A s show

n i n ExhibitD-1 , distances unde r worstcas e meteorologica

l condition s exten

d from 1,79

0 t o 635 0 meter

s fo r gases , compare

d t o 46 0 t o 139 0 meter

s unde r moderat e conditions . Fo r th e othe r consequenc e types , th e result s were th e same fo

r bot h meteorologica

l conditions , indicating tha tvaryin g meteorologica

l condition s probabl

y hav e littl e effe a o n th e potentia

l consequence s o

f vapor cloud explosions , BLEVEs , an d poo l fires . 

## \<t *P.1 6

APPENDI

X E INPUT S FOR MODELLIN G

\<&-P.1 7

-109 - Appendi x E . Inputs for Modellin g
Thi s appendi

x present s th e input

s for th e consequenc e analyses . Temperature s an d pressures assume

d a s storag e condition s for eac h o f th e chemical s modelle d are liste d i n ExhibitE-1 . ExhibitE- 2 present s th e physical/chemica

l propert y dat a use d for modelling . Th e dat a show n were use d for WHAZA N modelling , whic h require d mor e dat a tha n th e othe r methods . Th e sam e dat a were used as require

d fo r modellin g b

y th e othe r methods ; i n som e case s th e method s require d conversio n o f

th e dat a t o differen

tunits . Exhibit E- 3 show s th e assumptions use d fo r WHAZA N modellin g for instantaneou s release s an d moderat

e meteorology . Th e sam e meteorologica l assumptions were used i n modellin g b y th e othe r methods . Assumption s for WHAZA N modellin g o f prolonge d release s are show n i n ExhibitE-4 , an

d assumptions for WHAZA N modellin g unde r worst-cas e meteorologica l condition s ar

e show n i n ExhibitE-5 . Modellin g for prolonged release s an d for worst-cas e meteorology wa s don e onl y wit

h WHAZAN . ExhibitE- 6 present s th e dat a an d assumptions use d for ARCHI E modelling .

\<&P.1 8

-110 - Exhibi tE- 1 Temperatures an d Pressure s Use d i n Scenario s

Chemica l Gase s Ethylen e Propylene Propan e Butan e Ethylen e oxid e Ethyl chlorid e Liquid s Acetaldehyd e Pentan e Gasolin e Hexan e Heptan e Toluen e p-Xylen e Aceton e Trichloroethylen e Aceti c ad d Benzaldehyd e Dimethyl sulfoxid e Storag e

Temo.(°K)

17 5 29 3 23 2 29 3 29 3 28 8

29 3 29 3 29 3 29 3 29 3 29 3 29 3 29 3 29 3 29 3 29 3 29 3 Conditions

Press.(Bars )

1 3 13 3 1 3 6 3 6.1 8 1 3

1.01 3 2.74 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3 1.01 3

\&*.

# < ? o^ PROPERTIE S CA S Nunbe r Liqui d Hea t Capacit y

(J/kg/K ) Liqui d Densit y

(kg/cub e m ) Gamm a Rati o o f Specifi c Hea t Hea t o f Evaporatio n (J/kg ) Hea t o f Combustio n (J/kg ) Lowe r Flamnablllt y

Limi t (fract. ) Uppe r Flamnablllt y

Limi t (fract. ) Soilin g Poin t a t 1 Atmos . (K ) Molecula r Veigh t Vapo r Hea t Capacit y

(J/kg/K ) Critica l Temperatur e (K ) Saturate d Vapo r Pressur e (Bara ) Liqui d Enthalpy

(J/kg ) Vapo r Enthalpy

(J/kg ) Vapo r Entropy

(J/kg/K ) Saturate d Vapo r Temperatur e (K ) Vapo r Densit y

(kg/cub e m )

PROPERTIE S CA S Numbe r Liqui d Hea t Capacit y

(J/kg/K ) Liqui d Densit y

(kg/cub e m ) Garnn a Rati o o f Specifi c Hea t Hea t o f Evaporatio n (J/kg ) Hea t o f Combustio n (J/kg ) Lowe r Flamnablllt y

Limi t (fract. ) Uppe r Flamnablllt y

Limi t (fract. ) Boilin g Poin t a t 1 Atmos . (K ) Molecula r Weigh t Vapo r Hea t Capacit y

(J/kg/K ) Critica l Temperatur e (K ) Saturate d Vapo r Pressur e (Bara ) Liqui d Enthalpy

(J/kg ) Vapo r Enthalpy

(J/kg ) Vapo r Entropy

(J/kg/K ) Saturate d Vapo r Temperatur e (K ) Vapo r Densit y

(kg/cub e m ) ETHYLEN E 7485 1 2750. 0 569. 0 1.25 5 4.83E+0 5 -4.72E+0 7 0.02 7 0.28 6 170.82 8 28.0 5 700. 0 283. 1 — -6.69E+0 5 -39600 0 -131. 1 171.04 9 1.16 3

ACETALDEHYD E 7507 0 2483.0 9 783. 4 1.18 2 5.69E+0 5 -2.51E+0 7 0.01 6 0.10 4 293.5 5 44.05 3 946.6 3 461. 0 1.19 8 7.40E+0 5 28223 7 5679.5 2 298.1 5 PROPYLEN E

11507 1 2500. 0 520. 0 1.15 2 4.38E+0 5 -4.58E+0 7 0.02 0 0.11 1 227.42 3 42.0 8 1000. 0 365. 0 11.71 7 -4.35E+0 5 -6500 0 -131. 7 227.7 1 1.74 4

ACETON E 6764 1 2176. 0 789. 9 1.12 7 5.11E+0 5 -2.86E+0 7 0.02 6 0.12 8 329.4 4 58.0 8 1296. 7 0.30 6 51367 1 2.84E+0 5 5085.2 3 298.1 5 Exhibi t E- 2 Chemica l Dat a Use d fo r Model s

PROPAN E 7498 6 2400. 0 590. 0 1.1 3 4.26E+0 5 -4.60E+0 7 0.02 1 0.09 5 229.27 3 44.0 9 1100. 0 369. 8 9.62 2 -4.33E+0 5 -6200 0 -144. 2 229.57 5 1.82 8

DIMETHY L SULFOXID E 6768 5 1957.6 3 1095. 4 6.03E+0 5 -1.98E+0 7 0.02 6 0.28 5 462.1 5 78.12 9 459.8 8 72 6 0 0.00081 2 5.84E+0 5 13711 3 3920.0 6 298.1 5 BUTANE

7528 5 2500. 0 600. 0 1.09 2 3.90E+0 5 -4.54E+0 7 0.01 8 0.08 4 274.84 3 58.1 2 1200. 0 425. 0 2.28 2 -4.37E+0 5 -8100 0 -54. 4 275.18 3 2.40 9

TRICHLORO ETHYLEN E 7901 6 946.5 8 1464. 2 1 11 6 2.40E+0 4 -6.58E+0 6 0.12 5 0.9 0 360. 1 131.38 9 390.3 8 571. 0 0.098 3 2.82E+0 5 11639 2 2474.7 3 298.1 5 PENTAN E

10966 0 2207. 0 626. 0 1.08 6 3.67E+0 5 -4.54E+0 7 0.01 5 0.07 8 312.66 9 72.1 5 1547. 0 469. 7 0.59 3 4.33E+0 5 -4040 0 -157. 0 313.05 6

ETHYL CHLORID E 7500 3 1616.9 8 897. 8 1.15 5 3.79E+0 5 -1.99E+0 7 0.03 8 0.15 4 285.4 2 64.51 4 970. 9 460.3 5 1.58 8 3.42E+0 5 20552 3 4274.7 3 298.1 5 2.8 7 GASOLIN E 800661 9 2056. 0 732. 0 1.05 4 3.20E+0 5 -4.35E+0 7 0.01 4 0.07 4 332.22 6 72.0 0 1234. 0 787. 0 0.50 1 0.00E+0 0 39000 0 -1429. 0 332.95 2

ETHYLEN E OXID E 7521 8 1979. 0 869. 0 1.21 2 5.80E+0 5 -2.67E+0 7 0.0 3 1.0 0 261.81 4 44.0 5 1006. 0 469. 0 1.69 9 -6.29E+0 5 -2640 0 -100. 8 282.11 8 1.82 6

- HEXANE 11054 3 2456.1 9 659. 0 1.06 3 3.35E+0 5 -4.48E+0 7 0.01 4 0.07 4 344.58 9 86.1 7 1819. 0 507. 4 0.17 5 -4.25E+0 5 -4020 0 -171. 6 344.99 5

ACETI C ACI D 6419 7 2048. 2 1042. 9 1.14 5 4.05E+0 5 -1.31E+0 7 0.05 4 0.1 6 391.0 5 60.05 2 1114. 0 592.7 1 0.01 6 4.72E+0 5 22646 0 4197.5 3 294.3 0 HEPTAN E

14282 5 2605.7 4 683. 8 1.04 5 3.17E+0 5 -4.46E+0 7 0.01 2 0.06 7 374.55 7 100.2 1 1992.2 6 540. 7 0.05 5 -4.23E+0 5 -4020 0 -203. 3 374.99 3

BENZALOEHYD E 10052 7 1676. 3 1041. 5 1.1 0 3.62E+0 5 -3.20E+0 7 0.01 5 0.1 0 452. 2 106.12 4 981. 8 694. 8 0.000 9 5.00E+0 S 29272 4 297.0 0 TOLUEN E

10888 3 1738. 0 867. 0 1.08 9 3.61E+0 5 -4.06E+0 7 0.01 2 0.07 0 383.11 1 92.0 0 1122. 0 592. 0 0.03 9 3.17E+0 5 74600 0 -273 2 6 383.55 3 P-XYLEN E

10642 3 1750. 0 86 1 0 1.07 1 3.40E+0 5

- 4 08E+0 7 ' 0.01 1 0.07 0 410.0 5 106.0 0 119 3 0 616^ 2 0.01 2 0.00E+0 0 41700 0 -1527. 5 410.50 9 - ,

-w

• >- *

iExhibi tE- 3 WHAZA N Modelling Dat

a fo r Instantaneou s Releases , Moderat e Meteorolog

y

Dat a Input s Ethylen e Storag e Temperatur

e (K ) 175. 0 Storag e Pressure (Bar ) 1. 3 Anfelen t Temperatur

e (K ) 293. 0 Store d Mas

s (kg ) 4536 0 Bun d Are a (m2 ) 0.00 0 Win d Spee

d (m/s ) 3.00 0 Ma x Tim e o f Interes t (s ) 10000 0 BUOYAN T PLUM E DISPERSIO

N Effectiv e Releas e Heigh t (m ) 0.00 0 Releas e Rat e (kg/s ) 761. 0 Min . Cone , o f Interes t (ppm ) 13500 Wind Spee

d (m/s ) 3.00 0 Anbien t Temperatur

e (K ) 293. 0 Surfac e Roughnes

s Paramete r 000. 1 Atmospheri c Stabilit y Categor y D Propylen e Propan e

293. 0 13. 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 265. 7 1000 0 3.00 0 293. 0 000. 1 D 232. 0

1. 3 293. 0 4536 0 0.00 0 3.0 0 10000 0

0.00 0 244. 5 1050 0 3.0 0 293. 0 000. 1 D Butan e

293. 0 6. 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 157. 4 900 0 3.00 0 293. 0 000. 1 D Pentan e

293. 0 2.7 4 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 96.2 5 750 0 3.00 0 293. 0 000. 1 D Gasolin e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 88.2 5 700 0 3.00 0 293. 0 000. 1 D Hexan e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 54.8 1 700 0 3.00 0 293. 0 000. 1 D Heptan e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 31.9 4 600 0 3.00 0 293. 0 000. 1 D Toluen e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3. 0 10000 0

0.00 0 24.0 4 600 0 3.00 0 293. 0 000. 1 D p-Xylen e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3. 0 10000 0

0.00 0 14.1 1 550 0 3.00 0 293. 0 000. 1 D

t

o

Oat a Input s Storag e Temperatur e (K ) Storag e Pressur e (Bar ) Ant> i en t Temperatur

e (K ) Store d Mas s (kg ) Bun d Are a (m2 ) Wind Spee d (m/s ) Ma xTime o f Interes t (s )

BUOYANT PLUM

E DISPERSIO

N Effectiv e Releas e Heigh t (m ) Releas e Rat e (kg/s ) Min . Cone , o f Interes t (ppm ) Wind Spee d (m/s ) Anfeien t Temperatur e (K ) Surfac e Roughnes s Paramete r Atmospheri c Stabilit y Categor y Ethylen e Oxid e

293. 0 6.1 8 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 109. 6 1500 0 3.00 0 293. 0 0.10 0 D Ethy l Chlorid e

288. 0 1. 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 137. 4 1900 0 3.00 0 293. 0 0.10 0 D Acetaldehyd e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 102. 5 800 0 3.00 0 293. 0 0.10 0 D Aceton e 293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 44.5 1 1300 0 3.00 0 293. 0 0.10 0 D Trichloroethylen e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 44.5 2 6250 0 3.00 0 293. 0 0.10 0 D Aceti c Aci d

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 30.8 4 2700 0 3.00 0 293. 0 0.10 0 0 Benzaldehyd e

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 1.3 8 750 0 3.00 0 293. 0 0.10 0 D Dfmeth )

293. 0 1.01 3 293. 0 4536 0 0.00 0 3.00 0 10000 0

0.00 0 3.35 7 1300 0 3.00 0 293. 0 0.10 0 DExhibi tE- 4 WHAZA N Modelling Dat

a fo r Prolonge

d Release s

Dat a Input s Ethylen e Propylen e Propan e Butan e Storag e Temperatur e (K ) 175. 0 293. 0 232. 0 293. 0 Storag e Pressur e (Bar ) 1. 3 13. 3 1. 3 6. 3 Anfcien t Temperatur e (K ) 293. 0 293. 0 293. 0 293. 0 Store d Mas s (kg ) 4536 0 4536 0 4536 0 4536 0 Releas e Are a (m2 ) 0.00 1 0.00 1 0.00 1 0.00 1 Discharg e Coefficien t 0.60 0 0.60 0 0.60 0 0.60 0 Liqui d Hea

d (ra ) 4.3 3 4.3 3 4.3 3 4.3 3 Bun d Are a (m2 ) 0.00 0 0.00 0 0.00 0 0.00 0 Wind Spee d (m/s ) 3.00 0 3.00 0 3.0 0 3.00 0 Ma xTim e o f Interes t (s ) 10000 0 10000 0 10000 0 10000 0

BUOYAN T PLUM E DISPERSIO

N Effectiv e Releas e Heigh t (m ) 0.00 0 0.00 0 0.00 0 0.00 0 Releas e Rat e (kg/s ) 4.72 8 0.27 1 4.85 3 0.38 6 Hln . Cone , o f Interes t (ppm ) 1350 0 1000 0 1050 0 900 0 Win d Spee d (m/s ) 3.00 0 3.00 0 3.00 0 3.00 0 Ambien t Temperatur e (K ) 293. 0 293. 0 293. 0 293. 0 Surfac e Roughnes s Paramete r 000. 1 000. 1 000. 1 000. 1 Atmospheri c Stabilit y Category

D D D D Pentan e 293. 0 2.7 4 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3. 0 10000 0

0.00 0 0.45 4 750 0 3.00 0 293. 0 000. 1 D Gasolin e

293. 0 1.01 3 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3. 0 10000 0

0.00 0 4.13 2 700 0 3.00 0 293. 0 000. 1 D Hexan e

293. 0 1.01 3 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3.00 0 10000 0

0.00 0 3.72 9 700 0 3.00 0 293. 0 000. 1 D Heptan e

293. 0 1.01 3 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3.00 0 10000 0

0.00 0 3.86 6 600 0 3.00 0 293. 0 000. 1 D Toluen e

293. 0 1.01 3 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3.00 0 10000 0

0.00 0 4.87 9 600 0 3.00 0 293. 0 000. 1 D p-Xylen e

293. 0 1.01 3 293. 0 4536 0 0.00 1 0.60 0 4.3 3 0.00 0 3.00 0 10000 0

0.00 0 4.84 6 550 0 3.00 0 293. 0 000. 1 0

T J. Exhibi tE- 5 WHAZA N Modelling Dat

a for Instantaneou s Releases , Wors tCas e Meteorolog

y

Dat a Input s Ethylen e Storag e Temperatur e (K ) 175. 0 Storag e Pressur e (Bar ) 1. 3 Ambien t Temperatur e (K ) 293. 0 Store d Mas s (kg ) 4536 0 Bun d Are a (m2 ) 0.00 0 Wind Spee d (m/s ) 1.50 0 Ma xTim e o f Interes t (s ) 10000 0
BUOYAN T PLUME DISPERSIO N Effectiv e Releas e Heigh t (m ) 0.00 0 Releas e Rat e (kg/s ) 576. 7 Min . Cone , o f Interes t (ppm ) 1350 0 Win d Spee d (m/s ) 1.50 0 Ambien t Temperatur e (K ) 293. 0 Surfac e Roughnes s Paramete r 0.10 0 Atmospheri c Stabilit y Categor y

F Propylen e

293. 0 13. 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 201. 4 1000 0 1.50 0 293. 0 0.10 0 F Propan e

232. 0 1. 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 244. 5 1050 0 1.50 0 293. 0 0.10 0 F Butan e

293. 0 6. 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 119. 3 900 0 1.50 0 293. 0 0.10 0 F Pentan e

293. 0 2.7 4 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 72.9 5 750 0 1.50 0 293. 0 0.10 0 F Gasolin e

293. 0 1.01 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 66.8 8 700 0 1.50 0 293. 0 0.10 0 F Hexan e

293. 0 1.01 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 41.5 4 700 0 1.50 0 293. 0 0.10 0 F Hcpt8n 6

293. 0 1.01 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 41.5 4 600 0 1.50 0 293. 0 0.10 0 F Toluen e

293. 0 1.01 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 18.2 2 600 0 1.50 0 293. 0 0.10 0 F p-Xylen e

293. 0 1.01 3 293. 0 4536 0 0.00 0 1.50 0 10000 0

0.00 0 10.7 0 550 0 1.50 0 293. 0 0.10 0 FExhibi tE- 6 ARCHI E Modelling Dat

a

CA S Numbe r PHYSIOCHEMICA

L PROPERTIE S O F MATERIA L Norma l Boiling Poin t (deg F ) Molecula r Weigh t Liqui d Specifi c Gravit y Vapo r Pressur e a t Containe r Tem p (psia ) Vapo r Pressur e a t Ambien t Temperatur e (psia ) Lowe r Flammabl e Limi t (volX ) Lowe r Hea t o f Combustio n (Btu/lb ) Ga s Explosio n Yiel d Facto r CONTAINE R CHARACTERISTIC S Tota l Weigh t o f Content s (lbs ) Temperatur e o f Containe r Content s (de g F ) Tan k Content s Durin g Firebal l (lbs ) ENVIRONMENTAL/LOCATIO N CHARACTE R ISTIC S Ambien t Temperatur e (deg F ) Wind Velocit y

(mph ) ETHYLEN E 7485 1
-151.9 1 28.0 5 18.9 0 2. 7 2029 2 0.0 6
10000 0 -144. 0 10000 0
68. 0 11. 9 PROPYLEN E

11507 1
-50.03 9 42.0 8 192.9 0 2. 0 1969 0 0.0 3
10000 0 68. 0 10000 0
68. 0 11. 9 PROPANE

7498 6
-46.7 1 44.CI lS . 8 5 2. 1 1977 6 0.0 3
10000 0 -42. 0 10000 0
68. 0 11. 9 BUTANE

7528 5
35.3 2 58.1 2 91.3 4 1. 8 1951 9 0.0 3
10000 0 68. 0 10000 0
68. 0 11. 9 PENTAN

E 10966 0
103.40 4 72.1 5 0.62 6 7.1 2 7.1 2 1. 5 1951 9 0.0 3
10000 0 68. 0 10000 0
68. 0 11. 9 6AS0LIN E

800661 9
138.60 7 72.0 0 0.73 2 6.4 9 6.4 9 1. 4 1870 2 0.0 3
10000 0 68. 0 10000 0
68. 0 11. 9 HEXANE

11054 3
160.8 6 86.1 7 0.65 9 2.0 5 2.0 5 1. 4 1926 1 0.0 3
10000 0 68. 0 10000 0
68. 0 11. 9 HEPTAN E

14282 5
214.80 3 100.2 1 0.683 8 0.6 2 0.6 2 1. 2 1917 5 0.0 3
10000 0 68. 0

68. 0 11. 9 TOLUEN E

10888 3
230. 2 92.0 0 0.86 7 0.4 4 0.4 4 1. 2 1745 5 0.0 3
10000 0 68. 0

68. 0 11. 9 P-XYLENE

10642 3
278.6 9 106. 0 0.86 1 0.1 3 0.1 3 1. 1 1754 1 0.0 3
10000 0 68. 0

68. 0 11. 9 c

n

c

o