p. 1



# OAR Box 1168 Prepped by Ollie Stewart



### Document

Number: 

# 64 ) ll-A- 2
Docket Number: 

# A-89-1 0

Printed 4/29/2008 11:23:18 AM Sheet 64 of 131P. 2 

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# &EP A Unite d State s Offic e o f Ai rQualit y Environmenta l Protectio n Plannin g an d Standard s A 9enc yResearc h Triangl e Par k N C 27^ * "

- EPA-450/3-86-00 2

Januar y198 6

Ai r 

# Emissio n Factor

s Fo r Equipmen t Leait

s O f VO C An d HA P 

# A-89-1 0

II-A- 2



### EPAAIRDOCXCT

_P. 3

* ' *



## EPA-450/3-86-00 2



# Emissio n Factor s fo r Equipmen t Leak s o f VO C an d HA P

Prepare d by : Radia n Corporatio n 320 0 E

. Chape l Hil l Road/Nelso n Highwa y Researc h Triangl e Park , N C 2770 9 Unde rEP

A Contrac t No

. 68-02-388 9

U.S

. ENVIRONMENTA L PROTECTIO N AGENC Y

Offic e o f Ai ran d Radiatio n Offic e o f Ai rQualit yPlannin g an d Standard s Emissio n Standard s an d Engineerin g Divisio n Researc h Triangl e Park , Nort h Carolin a 2771 1

Januar y198 6P. 4 

# V

DISCLAIME R Thi s repor

t ha s bee n reviewe d b y th e Offic e o

f Ai r Qualit y Plannin g an d Standards , U.S
. Environmenta l Protectio n Agency , an d approve d fo r publicatio n as receive d fro m th e Radia n Corporation
. Approva l does not signif

y tha t th e conten t necessaril y reflec t th e view s an d policie s o f th e U.S
. Environmenta l Protectio n Agency , no r does mentio n o f trad e name s o r commercia l products constitute endorsemen t or recommenda tio n fo r use . Copie s o

f thi s repor

t are availabl e fro m th e Nationa l Technica l InformationServices , 528 5 Por t Roya l Road , Springfield , Virgini a 22161
.

### TABL E O F CONTENT S P. 5



### £ia e LIS T O F TABLE S . . : ii i LIS T O F FIGURE S i v Sectio n1. 0 - OVERVIEW

1- 1 Sectio n2. 0 - FUGITIV E EMISSION SOURCE S 2- 1 2. 1 VALVE S , -.-.' . 2- 3 2. 2 PUMP S . . . 2- 6 2. 3 COMPRESSOR S . . . . . 2-1 0 2. 4 RELIE F DEVICE S . 2-1 1 2. 5 OPEN-ENDE DVALVE S ANDLINE S . 2-1 5 2. 6 SAMPLIN

GSYSTEMS . 2-1 5 t. 7---FfcANGES-AND-OTHER-CONNECTORS. ; . . . 2-1 7 Sectio n3. 0 - EMISSION

FACTOR S \ 3- 1 3. 1 STUDIE S CONSIDERE DI N SOCM I EMISSION

FACTORDEVELOPMEN T . 3- 1 3.1. 1 Petroleu

m Refinin g Assessmen t Study . ...... . 3- 2 3.1. 2 Fou r Uni t EPA

Stud y , . . . * 3- 5 3.1. 3 EPA 6-Uni t Stud

y 3- 5 3.1. 4 DuPon t Study

3- 5 3.1. 5 Exxo nCyclohexan e Stud y 3- 5 3.1. 6 EPA

24-Uni t Stud

y 3- 6 3.1. 7 Maintenanc e Study

3- 6 3.1. 8 Analysi s Repor t an dRevisio n o f SOCM I Emissio nFactor s 3- 7 3.1. 9 Germa nStudie s onFugitiv e Emission s 3- 7 3.1.1 0 Unio nCarbid e Stud y 3- 8 3.1.1 1 Analysi s o f Allie dHDP E Uni t Dat a 3- 9 3.1.1 2 SCAQM DStudy

3- 9 3.1.1 3 Cok e Ove nBy-produc t Recover y an d Ga s Plan t Studie s 3-1 0P. 6

TABL E O F CONTENTS (CONTINUED )

' E-%31 

### 3. 2 EPA' S CHOIC E O F DAT A FO RSOCM I EMISSION

FACTOR S 3-1 0 3. 3 EMISSION

FACTO RDEVELOPMEN T 3-1 2 3.3. 1 Detaile dProcedura l Method . . 3-1 2 3.3. 2 Statistica l Consideration s 3-1 4 3.3. 3 Leak/No-Lea k Approac h. 3-1 7 3.3.3. 1 Generatio no f Leaking an d Nonleakin g Emissio nFactor s 3-1 9 3.3.3. 2 Computatio no f Averag e Emissio nFactors . 3-2 0 3. 4 EMISSION

FACTOR S PRESENTE D I

N TH E AI D . . 3-2 2 3. 5 EXAMPL E HYPOTHETICA L CASE , 3-2 7 Sectio n4. 0 - EMISSION REDUCTIO N

. . 4- 1 4. 1 OVERVIEW

O F TECHNIQUE S . . . 4- 1 4. 2 LEA KDETECTIO N

AND REPAI R(LDAR ) 4- 2 4. 3 SUMMAR

YO F EMISSION

REDUCTION S 4- 7 Sectio n5. 0 - LIS T O F REFERENCE S T 5- 1

nP. 7



### LIS T O F TABLE S

Tabl e ' Pag e 3- 1 FUGITIVE EMISSION STUDIE S I

N TH E AI D 3- 3 3- 2 LEA

KFREQUENCIE S AN D EMISSION FACTORS : REFININGASSESSMEN T STUDY3- 4 3- 3 LEAKIN

GAND NONLEAKINGEMISSION FACTOR S FO

R FUGITIV E EMISSION S (kg/hr/source ) 3-2 1 3- 4 AVERAG E EMISSION FACTOR S FO

RFUGITIVE EMISSION S I N SOCM I 3-2 3 3- 5 LEA

KFREQUENCIE S BYPROCES S FO REQUIPMEN T I N 2 4 SOCM I UNITS . . . . . 3-2 8 3- 6 ESTIMAT E O F "UNCONTROLLED " FUGITIV E EMISSION S FOR

A HYPOTHETICA L CASE . 3-2 9 4- 1 LDA

RINPUT S AN D COMPUTE D REDUCTION S FOR SOCMI/MONTHL YMONITORING4- 4 4- 2 LDA

RMODE L RESULT S FO

RSOCM I VALVE S AN D PUMP S 4- 6 4- 3 CONTRO L LEVEL S FO RSOCM I FUGITIVE EMISSIONS : NSP S AND CT G4- 8

mP. 8

LIS T O F FIGURE S
Figur e ' Pag e 2- 1 Estimate d Emission s b y Sourc e Subcategorie s o f SOCM I . . 2- 2 2- 2 Diagram

o f a Gat e Valv e 2- 5 2- 3 Diagram s o f Valve s wit hDiaphrag m Seals . 2- / 2- 4 Diagram

o f a Doubl e Mechanica l Sea l (a ) Back-to-bac k Arrangemen t 2- 9 (b ) Tande m

Arrangemen t 2- 9 2- 5 Simpl e Single-stag e Reciprocatin g Compresso r 2-1 2 2- 6 Pressur e Relie f Valv e i na Basi c RD/PR V Combination . . . 2-1 3 2- 7 Schematic s o f Close d Purg e Samplin g System s 2-1 6 3- 1 Cumulativ e Distribution : Cumen e Ga s Valve s 3-1 3 3- 2 Cumulativ e Mas s Emission s Distribution :

Cumen e Ga s Valve s * 3-1 5 3- 3 Cumulativ e Distributio no f Tota l Emission s b y Screenin g Value s - Compariso no f Confidenc e Interval s ... . 3-1 8 3- 4 Compariso no f Emissio nFactors : Ga s Valve s ...... . 3-2 5 3- 5 Compariso no f Emissio nFactors : Ligh t Liqui dValve s

an d Pump s . 3-2 6 4- 1 Schemati c Diagra m o f th e LDA

RMode l 4- 3

i v

### GLOSSAR Y P. 9



### Averag e emissio nfacto r - th e pe r componen t mas s emissio nrat e applicabl e t o population s o f sources , no t individua l componen t measurements . Lea k definitio n- the'monitorin g instrumen t readin g selecte da s th e trigge r valu e fo r initiatin g some actio nsuc ha s maintenance ; e.g. , 10,00 0 ppm v i s th e lea k definitio nuse db y EPA . Lea k frequenc y

- th e percentag e o f source s ( a particula r equipmen t typ e an d service ) determine dt o b e leakin g base dupo na chose nlea k definition . Lea k rat e - se e mas s emission s rate . Leakin g emissio nfacto r - th e pe r componen t mas s emissio nrat e associate dwit h th e populatio no f source s wit hscreenin g value s a t o r abov e th e lea k definition . Mas s emission s rat e - th e quantit y o f volatil e organi c compound(s ) release dt o th e atmospher e interm s o f tota l mas s pe r uni t time . Monitorin g instrumen t - portabl e hydrocarbo nanalyze r meetin g th e performanc e specification s give ninMetho d21 . Non-leakin g emissio nfacto r - th e pe r componen t mas s emissio nrat e associate d wit hth e populatio no f source s wit hscreenin g value s les s thanth e lea k definition . Screenin g valu e - monitorin g instrumen t readin g generall y give ni n -^concentratio nunits ; e.g. , ppmv .P.1 0

1. 0 .OVERVIE W

On e o f th e firs t majo r effort s i n th e fiel d o f fugitiv e hydrocarbo n emission s wa s th e Join t Refiner yStud yinitiate d b yth e Lo s Angele s Count y APCD , th e Californi a Stat e Departmen t o f Publi c Health , and th e U
. S
. Publi c Healt h Servic e i n Augus t 1955
. Additiona l studie s wer e mad e subsequen t t o thi s origina l work
. Bu t i t wa s no t unti l th e mid

- t o late-1970' s tha t a renewe d interes t wa s sparke d b ytw o events
. Th e Clea n Ai r Act , originall ypasse d i n 1970 , lai d ou t th e groundwor k fo r th e U
. S
. Environmenta l Protectio n Agenc y(EPA ) t o se t standard s o f performanc e fo r newl yconstructed , modified , o r reconstructe d source s o f ai r pollutio n whic h ma yendange r th e publi c healt h o r welfare
. Sinc e thes e Ne w Sourc e Performanc e Standard s (NSPS ) wer e t o b e promulgate d fo r a larg e numbe r o f industrie s o r industr ysegments , a rankin g wa s develope d i n accordanc e wit h th e 197 7 amendment s s o tha t thos e industrie s wit h th e highes t potentia l fo r impactin g publi c healt h woul d b e examine d first

. Th e Syntheti c Organi c Chemica l Manufacturin g Industr y(SOCMI ) wa s place d firs t o n th e Priorit yLis t
o f industr ycategorie s a s th e singl e mos t significan t contributo r t o ai r pollution

. Aroun d thi s sam e time , a n extensiv e stud yo f atmospheri c emission s fro m petroleu mrefinin g wa s conducted
. Th e stud ywa s initiate d t o evaluat e existin g and developin g refinin g emission s contro l technologie s an d t o asses s th e potentia l impac t o f atmospheri c emission s fro mrefinin g o n th e surroundin g environment

. A s th e progra m began , fugitiv e emission s (i.e. , emission s fro m variou s type s o f equipmen t suc h a s valves , pumps , compressors , pressur e relie f devices , an d connectors ) wer e foun d t o b e a larg e (i f no t th e largest ) sourc e o f hydrocarbo n emission s fro mrefining

. A s a result , th e scop e o f th e Refinin g Stud ywa s expande d t o includ e th e quantificatio n o f fugitiv e emissions

. Thi s particula r objectiv e wa s give n adde d emphasi s a s a resul t o f th e Clea n Ai r Ac t
an d it s emission s offset s regulations , whic h requir e emissio n factor s fo r evaluatin g compliance

. Subsequen t t o th e refiner yassessment , EPA' s researc h grou p conducte d additiona l studie s i n chemica l plants
. Twenty-fou r separat e chemica l unit s



### 1- 1P.1 1

wer e evaluated . O f thes e units , si xwer e studie dmor e closel y fo r th e effec tivenes s o f emissio ncontro l techniques . Thes e ne w data , couple dwit ha revie w o f dat a from

othe r studies' , wer e compile dint o a nAdditiona l Informa tio nDocumen t (AID ) o nfugitiv e emission s o f VO C i nSOCMI . Th e AI D detail s EPA' s conclusion s abcfu t ho w t o estimat e emission s an demission s reduction s fo r fugitiv e emission s o f VOC .

. Th e concept s behin dfugitiv e emission s an dthei r contro l ar e relativel y simple ; however , th e understandin g o f fugitiv e emission s dat a i s quit e complex . No t surprisingly , th e estimate s o f emissions , emissio nreductions , an dcost s stil l dra w

th e bul k o f comments ' an dquestion s fro

m regulator y personne l a s wel l a s industr y representatives . Thi s documen t addresse s th e developmen t o f emissio nfactor s fo r fugitiv e VO C emission s (o r equipmen t leak s o f VOC) . Th e comment s an dquestion s mos t ofte nraise dar e give nbelow wit ha brie f response . Detaile d responses , ar e containe di nth e substantia l literatur e generate db y EP A t o suppor t th e fugitiv e emissio nstandards .

1 . M y emission s ar e already lo w becaus e o f OSHA

regulations . Why , then , ar e ther e als o environmenta l emission s standard s fo r equipment leaks ?

Environmenta l emission s standard s fo r equipmen t leak s hav e differen t purpose s from

OSHA regulations . Indeed , the y ma y eve nresul t indifferen t environmenta l benefits . Environmenta l standard s focu s o nreducin g th e tota l quantit y o f emissions , inthi s cas e VO C emissions , t o th e atmosphere . O nth e othe r hand , OSHA

regulations , unlik e environmenta l standards , d o no t necessaril y

limi t mas s emission s directly . OSHA regulation s permi t contro l o f emissio nsource s b

y substitutio nof, , chemical s wit hles s hazardou s materials , proces s modifications , worke r rotation , proces s o r worke r isolation , ventiTatio ncontrols , o r modificatio no f wor k practices . Suc hcontro l
measures , ar e focuse donreducin g occupationa l exposur e (a s a concentration), - no t necessaril y

reducin g mas s emission s o f VO C t o th e atmosphere . Th e ide a o f workplac e concentratio nreductio ni s th e key t o OSHA regulations . I t i s ofte nthough t tha t OSHA regulation s resul t in concentration s inth e workplac e wel l belo w 10,00 0 ppmv , th e concentratio n



### 1- 2P.1 2

f? *

'***• • .

leve l use dt o identif y leakin g component s unde r th e environmenta l regulations . A nimportan t distinctio ni s tha t environmenta l standard s cal l fo r measuremen t
o f VO C concentratio na t th e lea k interface , no t inth e surroundin g area . Fiel dstudie s hav e show ntha t th e concentratio no f VO C decrease s exponentiall y wit hincreasin g distanc e fro m th e lea k interface . Thus , a lea k determine da t th e interfac e wil l rarel y b e see na t a distanc e onl y 2 0 c m fro m th e surfac e an dye t substantia l quantitie s o f VO C ma y b e emitte dfro

m suc ha leak . Dispersio nan

ddilutio no f th e VO C int o th e surroundin g are a mas k th e severit y o f emission s fro

m th e leak . A s a result , whil e OSHA regulation s zzj

ne. . reduc e th e concentratio no f VO C i nth e workplace ^ the y do no t guarante e tha t th e tota l mas s emission s fro m leak s ar e als o reduced .

I already

contro l m

y emission s unde r th e Contro l Technique s Guideline . A m I subjec t t o mor e environmenta l standard s fo r equipmen t leaks ?

Ther e ar e severa l environmenta l regulator y program s inexistence : Nationa l Ambien t Ai r Qualit y Standard s (NAAQS) , State Implementatio nPlan s (SIP's) , Nationa l Emissio nStandard s fo r Hazardou s Ai r Pollutant s (NESHAP's) , an dNe w Sourc e Performanc e Standard s (NSPS's). ' Al l o f thes e type s o f regulation s wor k towar dmeetin g th e goal s o f th e Clea nAi r Act . Th e contro l technique s guidelin e document s (CTG ) ar e presentation s o f wha t i s considere db y EPA t o be "reasonabl y

availabl e contro l technology " (RACT) . RACT-base denvironmenta l regulation s ar e establishe db y State s t o correc t existin g ai r pollutio nproblems , focusin g onexistin g source s in particular . Th e contro l technique s discusse di nth e CT Gfo r SOCM I fugitiv e emissio nsource s ar e completel y consisten t an

dcompatibl e wit hstandard s se t unde r othe r environmenta l programs . Th e resultan t contro l level s ma y var y du e t o difference s i nth e frequenc y o f monitorin g o r th e us e o f equipmen t contro l techniques . RACT-base dstandard s woul dno t b e duplicativ e wit hstandard s se t unde r othe r environmenta l programs . NSPS' s ar e applicabl e onl y t o newl y constructed , modified , o r reconstructe dfacilities . Sinc e the y appl y t o new facilities , th e requirement s o f NSP S are . generall y mor e stringen t tha nthos e



### 1- 3P.1 3

o f RACT-base dstandard s se t fo r existin g facilities . I nth e cas e o f fugitiv e emission s control , fo r example , NSPS-base dstandard s woul drequir e monitorin g o f equipmen t mor e frequentl y tha nrequire dunde r RACT-base dstandards . Similarly , NESHAP' s ar e establishe dfo r al l facilities , ne w o r existing . Again , th e differenc e betwee nrequirement s o f NESHAP' s an dRACT-base d standard s i s basicall y th e degre e o f stringency . NESHAP' s requir e mor e frequen t monitorin g tha nRACT-base dstandard s fo r fugitiv e emissio nsources . Furthermore , NESHAP' s ofte nrequir e th e us e o f contro l equipmen t wher e RACT-base dstandard s ma y onl y requir e wor k practice s suc ha s lea k detectio n an drepairs . Sinc e NESHAP' s ar e applicabl e t o existin g sources , a s wel l a s ne w sources , thei r mor e stringen t requirement s woul dnee dt o b e met , inexces s o f RACT-base dstandard s fo r existin g sources . I nterm s o f emission s estimates , proces s unit s complyin g wit hth e RACT-base dstandard s presente dinth e CT Gwoul dindee dexhibi t lowe r emission s tha nwoul db e presente db y th e simpl e us e o f th e SOCM I emissio nfactors . A s show ninTabl e 4- 3 o f thi s documen t varyin g degree s o f emissio nreductio nar e achievabl e unde r th e differen t standard s (NSPS , NESHAP , CTG) . Emission s fro m proces s unit s complyin g wit hth e CT Gca nb e estimate db y applyin g th e prope r efficienc y

t o th e estimate duncontrolle demissions .

2 . Emission s fro

m m y proces s uni t ar e lowe r tha nth e SOCM I factor s indicate . I contro l th e emission s b y lookin g fo r leaks , sometime s smellin g fo r them . Why

shouldm

y uni t b e covere db

y thes e standards ?

Th e chemica l industr y i s comprise do f numerou s processe s producin g a larg e numbe r o f chemicals . Eac hproces s uni t ma y b y itsel f emi t a relativel y smal l amoun t o f VOC ; however , th e tota l amoun t o f VO C fro m th e industr y

i s significant . Therefore , individua l processe s o r unit s ar e no t exempted . EPA recognize s th e wid e variabilit y o f lea k percentage s ona uni t proces s basi s throughou t th e industry . O f th e 2 4 unit s surveye di nth e 24-uni t study , 1 5 demonstrate doveral l lea k frequencie s fo r valve s i ngas/vapo r andligh t liqui dservice s o f les s tha n2 percent . Environmenta l standards , therefore ,



### 1- 4P.1 4

provid e alternative s fo r unit s tha t exhibi t low-lea k characteristics . Fo r example , anowne r o r operato r o f a proces s uni t ma y elec t t o compl y

wit ha performanc e limi t o f 2 percen t leakin g valves . Insuc ha case , th e routin e lea k detectio nan

drepai r practice s require db y th e basi c rul e woul dno t be followed . Instead , th e proces s uni t woul db e screene d(usin g Referenc e Metho d 21 ) ona

nannua l basi s t o demonstrat e tha t th e uni t doe s indee ddemonstrat e th e lo w lea k characteristic s o f les s tha n2 percen t o f valve s leaking . EPA selecte dthi s valu e base dupo ncos t an demission s analyse s whic h showe dtha t monthl y

lea k detectio nan

drepai r fo r valve s i s no t a cos t effectiv e contro l techniqu e fo r proces s unit s exhibitin g very lo w lea k characteristics . Thes e characteristic s ma y resul t fro

m th e natur e o f th e chemical s processed , tigh t plan t design , o r enhance dmaintenance . Fugitiv e emission s fro m m y proces s uni t ar e lowe r tha nestimate dusin g SOCM I factors . I hav e verifie dth e low lea k rate s b

y measurin g th e concentratio nan

dflow rat e a t th e ventilatio noutlet .

I t ma y wel l b e tru e tha t actua l fugitiv e emission s fro m an y give nproces s uni t ar e lowe r tha nth e emission s estimate dusin g th e averag e SOCM I emissio n factors . Th e SOCM I factors , however , ar e applicabl e t o th e industr y a t large , an dshoul db e applie dt o an y individua l uni t wher e th e lea k frequencie s fo r equipmen t hav e no t bee nestablishe db y a rigorou s applicatio no f Referenc e Metho d21 . Concentratio nan dventilatio nflowrate s giv e a nindicatio no f th e magnitud e o f fugitiv e emissions ; the y woul dno t necessaril y provid e a

n accurat e estimat e o f tota l VO C fugitiv e emissions . Fo r proces s unit s tha t woul dhav e ventilatio noutlets , al l potentia l source s o f fugitiv e emission s ar e no t generall y

enclose di nth e building . Also , larg e building s tha t hous e chemica l proces s unit s ar e no t generall y ai r tight ; therefore , some VO C ma y no t b e accounte dfo r i nth e ventilatio nair . Furthermore , th e evaluatio no f fugitiv e emission s from a nenclose d buildin g represent s a comple xmeasuremen t problem . Al l emissio npoint s fro m th e buildin g woul dnee dt o b e measure dsimultaneousl y fo r 3 hour s t o constitut e a

nemission s test . Thi s i s th e onl y wa y t o ensur e tha t al l emission s fro

m non-vente dsource s woul db e accounte dfor . Sinc e fancurve s



### 1- 5P.1 5



### ar e inaccurat e fo r emission s measurements , EPA flo w measuremen t method s woul d nee dt o b e employed . Thes e method s requir e obstruction-fre e ductin g o neithe r sid e o f th e fan , a situatio nno t alway s foundi nventilatio napplications . Finally , whe napplie dt o th e estimatio no f hazardou s ai r pollutants , th e analytica l techniques ' use dmus t b e capabl e o f speciatio no f organi c constituents . Commo ndetector s ar e no t alway s adequat e fo r thi s task .
' Concentratio nandventilatio nflow rat e coul dindicat e tha t emission s ar e lowe r tha nestimate db y SOCM I factors . Thi s technique , however , woul dno t b e sufficien t t o prov e tha t emission s ar e low . Ther e i s a nacceptabl e alternativ e t o estimatin g emissions . Conductin g a rigorou s Metho d2 1 surve y woul dlea dt o computin g percen t leakin g value s (lea k frequency ) fo r al l equipmen t types . Thes e value s coul dthe nb e use dt o construc t unit-specifi c overal l emissio nfactor s usin g "leaking " an d"nonleaking " emissio nfactor s a s describe dinSectio n3.3.3 . Usin g suc ha procedur e woul ddevelo pemissio n factor s consisten t wit hth e vas t amoun t o f fugitiv e VO C emission s dat a gathere dt o date . Th e unit-specifi c emissio nfactors, , applie dt o th e equipmen t count s fo r th e proces s unit , lea dt o th e overall-estimat e o f VO C emissions . A s note di nthi s document , pre-surve y maintenanc e woul dinvalidat e th e result s o f th e surve y an destimates .
3 . I t i s no t appropriat e t o us e petroleu m refiner y

tes t dat a t o determin e SOCM I emissio nfactors .
Th e developmen t o f VO C emissio nfactor s fo r equipmen t leak s i s founde do n th e concep t tha t equipmen t leak s VO C a t th e same , rat e regardles s o f th e industr y o r proces s unit . Tota l emission s o r averag e emissio nrate s may vary , however , base dupo nth e relativ e percentag e o f leak s foundindifferen t proces s units . Indevelopin g VO C emissio nfactor s fo r equipmen t leak s i n SOCMI , EPA

examine dan

dconsidere dever y

study available . Thi s evaluation , explaine dinth e AID , make s i t clea r tha t th e dat a containe di nth e Maintenanc e Study

an d24-Uni t Study

ar e no t th e sol e sourc e o f dat a o n fugitiv e emissions . Numerou s studie s hav e bee nconducte dan dthes e wer e reviewe di nth e AID , pointin g ou t bot hstrength s andweaknesse s associate d wit heac hstudy . T o gai nmaximu m utilit y o f th e dat a fro

m thes e studies , interpretatio no f th e dat a i s required , drawin g upo nth e stron g point s o f a
1- 6P.1 6

study whil e considerin g it s weaknesses . Thi s evaluatio nan dinterpretatio no f th e dat a wa s don e i nth e contex t o f th e whol e bas e o f fugitiv e emission s work ; i t wa s no t don e jus t fo r isolate dstudies . Base dupo nthi s revie w an d. analysis , i t wa s determine dtha t th e relevan t dat a from differen t studie s had t o b e merge dan

dtransforme dt o provid e a usefu l metho dfo r estimatin g emissions . On e o f th e mos t importan t studie s wa s th e Petroleu m Refinin g Assessment . Th e Petroleu

m Refinin g Assessmen t wa s a nenormou s study

o f VO C emission s from al l facet s o f refining . A majo r goa l o f th e wor k wa s th e investigatio n o f fugitiv e emission s an dth e developmen t o f emissio nfactor s tha t coul dbe use dt o estimat e fugitiv e VO C emissions . Th e researc hprogram , therefore , wa s designe dt o gathe r dat a tha t woul dlen ditsel f t o generatio no f suc hfactors . A s a result , th e mas s emission s dat a collecte ddurin g th e Petroleu m Refinin g Assessmen t represen t th e bes t availabl e dat a o nVO C emission s fro

m fugitiv e emissio nsources . Mas s emission s dat a wer e gathere do nsource s inchemica l unit s t o evaluat e th e effect s o f maintenanc e o nemissions . Th e dat a wer e no t collecte dwit hemissio nfacto r developmen t a s th e primar y goal ; therefore , thes e mas s emission s dat a d o no t represen t th e highes t qualit y dat a onmas s emissio no f VO C fro

m fugitiv e emissio nsources . * Th e wor k don e i npetroleum refinerie s an

dsubsequen t studie s inchemica l proces s unit s indicate dtha t actua l mas s emission s (a s describe db y emissio n factors ) ar e relate dt o th e numbe r o f leakin g component s compare dt o th e numbe r o f non-leakin g components . Th e mas s emission s dat a fro m th e Petroleu

m Refinin g Assessmen t serve da s th e basi s o f emissio nfacto r developmen t fo r fugitiv e VO C source s i nSOCMI . Recognizin g tha t lea k frequencie s fo r equipmen t i nSOCM I wer e differen t fro m thos e reporte di nth e Refinin g Assessment , EPA

use dlea k frequenc y dat a fo r SOCM I t o weigh t th e mas s emission s dat a fro

m th e Petroleu

m Refinin g Assessmen t ingeneratin g th e SOCM I averag e emissio nfactors . Thi s procedur e i s detaile dinth e AI D an di nthi s report . I nth e AID , EP A compare dth e emissio nfactor s generate dusin g thi s approac hwit hth e factor s develope da s par t o f th e study o f maintenanc e effect s i nchemica l units . Th e factor s wer e foundt o be simila r excep t i nth e



### 1- 7P.1 7

cas e o f gas/vapo r servic e valves . Therefore , th e chemica l uni t dat a wer e used t o generat e th e emissio nfacto r fo r valve s i ngas/vapo r service .

4 . Usin g averag e SOCM I emissio nfactor s overestimate s emission s fro m m y proces s unit , becaus e o f th e inheren t natur e o f th e chemical s I use , thei r volatility , thei r value , etc .

Ingatherin g dat a onth e SOCMI , EPA sample da numbe r o f vastl y differen t chemica l proces s units . Characteristic s o f individua l chemical s wer e considere dinselectin g th e proces s unit s sample ddurin g th e 24-Uni t Study . Hi-volume , low-price dchemical s wer e included , a s wer e lower-volume , higher-price dchemicals . Chemical s wit hwidel y divergen t volatilitie s wer e include dalon g wit hchemical s tha t ar e particularl y odoriferous . No t surprisingly , th e frequencie s o f leak s foundrange dfro m nearl y zer o t o thirt y percent . Lea k frequencie s provid e a nindicatio no f th e relativ e quantit y o f
mas s emission s an

di t i s apparen t fro m thi s rang e o f lea k frequencie s tha t fugitiv e emission s fro m some unit s wil l b e highe r an dsome lowe r tha n estimate s base donth e SOCM I factors' . Th e mas s emission s estimate s generate d b y EPA usin g th e averag e SOCM I emission s factors " represen t a naverag e tha t i s applicabl e t o industry-wid e emission s estimates . Withou t conductin g a rigorou s Metho d2 1 surve y t o determin e th e lea k frequenc y (thereb

y generatin g averag e emissio nfactor s base do nth e leak/no-lea k facto r components) , th e averag e SOCM I emissio nfactor s standa s th e bes t estimator s o f fugitiv e VO C emission s currentl y

available .

5 . I hav e measure d emissio nrate s fo r some source s inm y plant . Wh

y aren' t thes e measurement s bette r tha nth e estimate s EPA supports ?

Th e emissio nfactor s supporte db y EPA ar e base dupo na vas t amoun t o f dat a gathere donfugitiv e VO C emissio nsource s usin g rigorou s samplin g protocols . Th e factor s fo r eac hequipmen t typ e hav e bee ndevelope d considerin g two type s o f data : lea k frequenc y dat a an

dmas s emission s data . Th e entir e distributio no f mas s emission s fro m eac hclas s o f source s ha s bee n



### 1- 8P.1 8



### considered . Fo r example , 7 6 individua l measurement s o f mas s emissio nfro m ga s valve s wer e take nacros s th e distributio no f screenin g value s (i.e. , analyse s measurements ) t o develo pa mas s emission s correlatio nt o b e applie dt o screenin g data . Simila r distribution s o f mas s emission s measurement s ar e necessar y

fo r eac hequipmen t typ e t o develo pth e correlation s use din generatin g averag e emission s factors . Furthermore , th e correlation s represen t onl y par t o f wha t cc«_

> int o th e emission s factors . Screenin g dat a (i.e , screenin g value s fo r al l equipmen t component s ar e neede dt o ensur e tha t th e entir e distributio no f screenin g value s i s include dinemissio nfacto r development . Limited , isolate dmeasurement s o f emissio nrate s fo r "some " sources , therefore , ar e no t representativ e o f th e entir e distributio no f source s i nthe proces s unit . Only*b y considerin g th e entir e distributio ncanth e emissio n facto r b e representative .
6 . How d o I estimat e emission s fo r m y plant.. . (A ) i f I hav e no data ? (B ) i f I hav e some measurements ? (C ) i f I hav e don e a rigorou s Metho d2 1 survey ?

Fo r proces s unit s wher e no emission s dat a ar e available , estimate s o f fugitiv e VO C emission s shoul db e mad e usin g equipmen t count s an dth e typica l averag e emissio nfactor s develope dfo r SOCMI . Th e developmen t o f thes e factor s give ninthi s document , wa s explaine di nth e Additiona l Informatio n Documen t (AID ) fo r VO C equipmen t leaks . Insom e cases , isolate demissio nrat e measurement s ma y hav e bee nmade . Thes e measurement s serv e t o giv e th e owne r o r operato r a "sense " o f th e quantit y o f mas s emission s tha t migh t b e emitte dfro m th e proces s unit . Again , however , th e averag e SOCM I factor s mus t b e employe dt o estimat e emission s whe nonl y

isolate dmas s emission s measurement s hav e bee nmade . Isolate dmeasurement s d o no t represen t th e entir e distributio no f screenin g value s an

dmas s emissio nrate s presen t ina proces s unit .

1- 9P.1 9

Th e alternativ e t o usin g th e averag e SOCM I factor s i s t o emplo y complet e lea k frequenc y

dat a gathere dusin g a rigorou s Metho d2 1 surve y o nal l equipmen t types . Ins o doing , th e leak/no-lea k approac hdescribe dwithi ncan b e use dt o estimat e emissio nfactor s fo r th e specifi c proces s uni t screened . Th e resultan t "custom ? emissio nfactor s woul dthe nb e applie dt o th e equipmen t count s fo r th e specifi c proces s uni t t o deriv e th e tota l fugitiv e VO C emission s estimat e fo r th e proces s unit . Thi s procedur e i s illustrate dfo r a n exampl e cas e i nSectio n3.5 . Th e initia l ste pi ngeneratin g surrogat e emissio nfactor s i s t o us e a rigorou s Metho d2 1 surve y o nal l source s f nth e proces s unit . Metho d2 1
surve y i s th e promulgate dmetho ddevelope db y EPA tha t i s use dt o monito r equipmen t fo r leaks . "Rigorous " mean s tha t a Usource s must b e screene dan d tha t n o maintenanc e o f source s shoul db e conducte dprio r t o screening . Conductin g maintenanc e immediatel y prio r t o conductin g th e Metho d2 1 surve y woul dbia s th e lea k frequencie s generate dan dthu s invalidat e th e subsequen t emission s estimate s base dupo nth e lea k frequencies . Emission s estimate dinthi s manne r shoul db e reviewe do na continual , i.e. , annual , basis . Fo r example , a s tim e passes ^ th e lea k frequencie s note d fo r individua l equipmen t type s i na proces s urri t ma y change . A

nannua l testin g usin g a rigorou s Metho d2 1 surve y woul densur e tha t emission s estimate s mad e usin g "custom " emissio nfactor s woul dremai nrepresentative" ^ th e proces s unit .

7 . I a m no t intereste di ntota l VO C emissions . How d o I estimat e emission s o f a specifi c pollutant ?

Th e estimate s o f VO C emission s represente db y th e averag e SOCM I emissio n factor s ar e tota l VO C emissions . I nman y instances , onl y

on e componen t i nth e VO C strea m

i s o f interest andth e estimat e o f emission s nee donl y reflec t the specifi c pollutant . I norde r t o reflec t compound-specifi c emissions , th e estimates , (o r emissio nfactor ) shoul db e apportione dt o reflec t th e singl e compoun d(o r component ) o f interest . A s illustrate dinSectio n3.5 , a simpl e mas s fractio napproac hca nb e applied ; tha t is , fo r equipmen t i nVO C servic e

1-1 0P.2 0

containin g Xweigh t percen t o f th e compoun do f interest , th e emissio nfacto r coul db e apportione db y X/10 0 t o reflec t emission s o f onl y th e singl e compound .
8 . Th e contro l cost s associate dwit hlea k detectio nan drepai r ar e to o high , particularl y

i nligh t o f low

emission s reduction .

EP A base dit s estimate s o f cos t o ncos t dat a gathere dfro m industria l
source s durin g standard s developmen t activities . Th e time estimate s use dfo r equipmen t monitorin g (i.e. , screening ) an dfo r repai r (o f valves ) wer e base d
o ninformatio nsupplie db y industry . Cos t an

dcos t effectivenes s analyse s wer e conducte dfo r contro l o f individua l equipmen t type s an dfo r complet e proces s units . Th e cost s o f regulator y alternative s fo r equipmen t type s wer e judge dt o b e reasonable . Likewise , fo r proces s unit s considere donth e average , th e cost s wer e foundt o b e reasonable . EP A recognized , however , tha t no t al l proces s unit s coul db e considere d th e mode l uni t averag e SOCM I norm , describe db y mode l equipmen t count s an d averag e SOCM I emissio nfactors . Ther e ar e tool s t o examin e regulator y alternatives , a s applie dt o a nentir e industry. * Therefore , EPA considere d alternativ e contro l option s fo r thos e situation s wher e cost s became unreasonabl e wit hrespec t t o th e amoun t o f emission s controlled . Anexampl e o f alternativ e standard s allowe db y EP A i s th e 2 percen t leakin g performanc e limi t fo r valves . Init s analysi s o f regulator y alternatives , EPA

determine d tha t th e cost s o f contro l fo r proces s unit s wit hles s tha n1 percen t leakin g valve s wer e to o hig hfo r th e relativel y smal l emission s reduction s achievabl e b y routin e lea k detection s an drepai r (monthly) . T o allow fo r variabilit y

in measurements , EPA

provide da limi t o f 2 percen t leaking . A s evidence db y dat a gathere ddurin g th e 24-Uni t Study , ther e ar e proces s unit s whic hexhibi t lo w leak ' characteristics . Owner s o r operator s o f suc hunit s coul dop t fo r meetin g a 2 percen t (o r lower ) performanc e limi t o f leakin g valves , a s demonstrate db y a nannua l Metho d2 1 performanc e test .

1-1 1P.2 1

2. 0 FUGITIV E EMISSIO N SOURCE S

Th e term

fugitiv e emission s use di nth e contex t o f volatil e organi c compound s (VOC ) refer s t o leak s from equipmen t suc ha s valves , pumps , com pressors , etc . Th e ter m fugitiv e emissions , als o calle dequipmen t leaks , mean s th e los s o f VO C throug hth e sealin g mechanis m separatin g th e proces s flui d(containe di nth e equipment ) fro m th e atmosphere . Fugitiv e emission s ar e generall y mor e diffus e tha nmos t poin t source s o f emissions , especiall y whe nconsiderin g th e collectiv e emission s from widel y disperse dequipmen t withi na processin g plant . *A s note db y th e emission s estimate s presente di nFigur e 2-1 , fugitiv e emission s contribut e a larg e proportio no f VO C emission s from th e chemica l industr y overal l (abou t 3 5 per cent). 1 A s wit hprocess-relate dsources , fugitiv e emission s source s ar e readil y identifiabl e piece s o f equipmen t withi na processin g plant . Bu t a majo r differenc e i s i nth e numbe r o f source s foun dinan y give nproces s unit . Whil e ther e ma y

be onl y

a few process-relate dsource s withi na proces s uni t (e.g. , a reacto r trai nandassociate ddistillatio ncolumn s fo r purification) , ther e can b e hundred s o r thousand s o f valves , pumps , flanges , compressors , andothe r fugitiv e emissio nsource s withi na proces s unU . An dwhil e fugitiv e emission s o na pe r componen t basi s ca nbe small , th e collectiv e tota l o f emission s fro m al l fugitiv e source s withi na proces s uni t ca nb e large . No singl e contro l techniqu e i s applicabl e t o th e contro l o f al l type s o f equipmen t leaks . Neithe r i s a singl e emissio nlimi t universall y applicabl e t o equipmen t leaks . Rather , eac htyp e o f fugitiv e emissio nsourc e mus t be considere dindividuall y inestablishin g appropriate , applicabl e contro l techniques . Equipmen t controls , operationa l practices , andwor k practice s ar e al l vali dapproache s t o reducin g o r eliminatin g VO C emission s from equipmen t leak's , dependin g o nth e equipmen t type . Chemica l proces s plant s ar e comprise do f numerou s majo r equipmen t com ponent s suc ha s reactors , accumulators , storag e tanks , distillatio ncolumns , condensers , andheaters . Ther e i s als o a larg e clas s o f ancillar y equipment ,



### 2- 1r o

i Organi c Chealca l Manufacturin g 54 4 Gg/y

r (1001 )

Proces s Source s 

# 1 I

Reactor Operation s 

# I I

Ai r Oxidatio

n Processe s

U O Gg/y

r (201 ) 

# 1

Reacto r Processes "

3 2 Gg/y r (61 ) «
Non-Proces s Source s

\

Distillatio

n Operation s

H O Gg/y

r (261 ) Equipnent Leak s

18 9 Gg/y

r (351 ) -Storag e o f Organi c Liquid :

4 7 Gg/y r 

## (ax ) m

Secondar

y Sources c

2 6 Gg/y r (5X )

a Estlnate s fo

r proces s emissions source s estlnate d usin g bes t availabl e Infornatio n fro a curren

t standard s developmen

t prograa s (2 5 Octobe r 1902) . Reacto r processe s categor y encovpasse s al l processe s other tha n ai r oxidatio

n procosscs . Secondary

an d nlscellaneou s enission s estlnate d a s 5 percen

t o f th e total o f th

e other sources .
Figur e 2-1 . estimated Emission s b y Sourc e Subcategorie s o f SOCMI ^mos t o f whic hinvolve s th e transpor t o f chemical s an dcontro l o f chemica l flo w throug hth e proces s unit . Thes e component s include :

- Valve s

- Pump s

- Compressor s

- Pressur e Relie f Device s

- Open-Ende dValve s o r Line s

- Samplin g Connection s

- Flange s an

dOthe r Connector s Thes e ancillar y

item s o f equipmen t ar e fugitiv e e'missio nsources .
2. 1 VALVE S

Th e valv e i s on e o f th e mos t basic , commo nelement s foun dinth e chemica l plant . Valve s ar e availabl e i nnumerou s design s fo r widel y varyin g applica tions : gate , globe , control , plug , ball , check , an drelief . Mos t o f thes e valv e design s (chec k andrelie f valve s excepted ) hav e a va-lv e ste m whic h operate s t o restric t o r t o ope nth e valv e fo r flui dflow . Typicall y th e ste

m i s seale db

y a packin g glan do r 0-rin g t o preven t leakag e o f proces s flui dt o th e atmosphere . Packin g gland s ar e th e mos t commonl y use dsealin g mechanis m fo r valves , an

da wid e variet y

o f packin g material s ar e availabl e t o sui t mos t operationa l requirement s o f temperature , pressure , an dcompatibility . Becaus e o f desig nan

dmaterial s limitations , 0-ring s ar e muc hles s commo na s th e sealin g mechanis m

fo r valve s i nchemica l plants . Wit htime an

dprolonge duse , th e packin g o r sealin g 0-rin g inth e valv e ca nfail . T o eliminat e th e VO C leakag e resultin g fro m th e sea l failure , th e valv e packin g an

dseal s mus t be replace do r th e valv e body repaire do r replaced . Lea k detectio nandrepai r method s ar e effectiv e mean s o f reducin g th e leakag e o f VO C fro m thi s clas s o f source s ina plant . Basically , a ' lea k detectio nan

drepai r (LDAR ) progra m i s a systemati c progra m o f routinel y monitorin g individua l source s (i nthi s case , valves ) t o identif y thos e source s whic har e leaking . Thos e leakin g source s woul dthe nb e targete dfo r repai r

Fo r differen t sourc e type s o r industries , th e definitio no f a lea k ma y vary . Fo r th e purpos e o f thi s document , th e lea k definitio ni s a screenin g valu e greate r tha no r equa l t o 10,00 0 ppm v rea do na portabl e organi c compoun d analyzer , inaccordanc e wit hMetho d21 . 

### 2- 3

______ •(i.e. , eliminatio no f th e "leak" ) an d fo r subsequen t follow-u pmonitorin g t o ensur e tha t th e repai r had indee dbee neffectiv e i neliminatin g th e leak . Maintenanc e o r repai r technique s ca nrang e fro m simple , on-lin e mainten anc e t o comple xtechniques . Som e basi c type s o f maintenanc e tha t ca nbe . performe d ona valv e whil e i t remain s in-plac e an dinservic e are : (1 ) tightenin g o r replacemen t o f bonne t bolts , (2 ) tightenin g o f packin g gland nuts , an d (3 ) injectio no f lubrican t int o th e packin g o r seal . Thes e valv e component s ar e illustrate dinFigur e 2-2 . Bu t simpl e on-lin e technique s ar e no t alway s applicabl e o r effectiv e i nreducin g emissions . Fo r example , operationa l o r safet y requirement s ma y

prohibi t repai r o f some valve s suc ha s contro l valve s b y simpl e means . Othe r valve s simpl y canno t be repaire d effectivel y on-lin e an

d canno t be remove dfro m service . I

nsom e instances , repai r o f valve s ca nb e effecte dthroug hmor e sophisticate drepai r techniques . A

nexampl e woul dbe th e injectio no f a sealin g flui dint o th e equipment . Thoughrelativel y expensive , sealan t injectio nha s bee nprove n effectiv e inpetroleu m refinin g application s i nCaliforni a wher e virtuall y 3 complet e eliminatio no f leak s ha s bee nmandated . Incase s wher e maintenanc e o r repai r o f valve s i s no t possible , valv e replacemen t ma y b e required . Ther e ar e some valv e type s an ddesign s tha t hav e littl e o r n o potentia l fo r leakag e o f proces s fluids : valve s wit h"leakless " o r "sealless " technology . Tw o example s ar e bellow s seale dvalve s an ddiaphragm

valves . Bellow s seal s ar e th e mos t effectiv e sealin g mechanis m fo r valves . Sinc e th e servic e lif e o f th e bellow s ca nb e quit e variable , bellow s seal s ar e typicall y backe d u

p wit hconventiona l packin g glands . Bellow s seal s hav e bee nuse d primaril y

i nth e nuclea r powe r industr y wher e th e relativel y hig hcos t ca nb e justifie d b

y stringen t safet y

requirements . Diaphragm valves , th e othe r majo r typ e o f "leakless " valve , us e a diaphragm o f some appropriat e materia l t o sea l th e proces s flui d fro m th e stem

o f th e valve . In,some designs , th e diaphragm act s a s th e flow

contro l elemen t a s wel l a s th e sealin g mechanism . Tw o



### 2- 4P.2 5

PACKIN G GLAN D
PACKIN G

VALV E STE M POSSIBL E LEA KAREA

S

70-1769- 1



### FIGUR E 2-2
. DIAGRA M O F A GAT E VALV E

2-5P.2 6

typica l design s o f diaphragm valve s ar e show

ni nFigur e 2-3 . Diaphragm valves , however , ar e a sourc e o f fugitiv e emission s i f th e diaphragm fails .
2. 2 PUMP S

0 Pump s ar e integra l piece s o f equipmen t inmos t chemica l processes , providin g th e motiv e forc e fo r transportin g fluid s throughou t a plant . Th e centrifuga l pum

pi s th e chie f desig nuse dinth e SOCMI , bu t othe r pum plypei . ar e als o used . Leakag e o f proces s flui dt o th e atmospher e ca noccu r wher e th e movin g pum

pshaf t meet s th e stationar y casing . T o minimiz e suc hleakage , tw o sealin g technique s ar e commonl y applied : packe dseal s an dmechanica l seals . Lea k detectio nan

drepai r programs , describe dearlie r fo r valves , ar e als o applicabl e t o pump s wit hth e potentia l t o lea k a t th e seal . Pump s wit h maintaine dmechanica l seal s generall y lea k les s tha nd o pump s wit hpacke d seals . Failur e o f a mechanica l seal , however , ca nresul t i nlarg e emission s from th e pump . Routin e monitorin g ca neffectivel y identif y

pum psea l leak s an dmaintenanc e repai r ca nreduc e emissions . < Packe dseal s consis t o f a "stuffin g box " i nth e pum pcasing . Speciall y selecte dpackin g material s (chose no nth e basis-o f th e proces s material s an d environment ) ar e compresse dint o th e stuffin g boxwit ha packin g gland , resultin g i na tigh t sea l aroun dth e shaft . Sinc e th e shaf t mus t move , eithe r rotationall y

o r laterally , lubricatio nmus t b e supplie dt o th e packin g an d shaf t t o preven t excessiv e hea t generatio nfro m th e frictio nbetweenth e shaf t
an dpackin g whic hcoul dshorte nth e lif e o f th e equipment . Leak s ma y resul t fro m th e degradatio no f th e packing . Leak s from

packe dseal s ca nofte nb e reduce db y tightenin g th e packin g gland . Bu t a t some point , th e packin g wil l hav e deteriorate dt o th e exten t tha t i t mus t b e replaced . Often , pum ppackin g ca nonl y

b e replace dwhe nth e pum pi s ou t o f service . Mechanica l seals , singl e an ddual , ar e use dt o sea l pump s wit hrotatin g shafts . Bot hhav e th e commo nattribut e o f a lappe dsea l fac e betwee na stationar y

elemen t an

da rotatin g sea l ring . Althoug hmechanica l seal s ar e no t leakles s sealin g devices , th e leakag e o f proces s flui dfrom th e sea l ca n b e minimize db

y a properl y

installe dandoperatin g mechanica l seal .



### 2- 6P.2 7

/ ,

DIAPHRAG M

DIS K (A ) STE M

DIAPHRAG M

70-1771- 1



### FIGUR E 2-3
. DIAGRAM S O F VALVE S WIT H DIAPHRAG M SEAL S

2- 7P.2 8

Sinc e a mechanica l sea l wil l lea k (unles s routinel y replaced) , th e ultimat e potentia l fo r leakag e ca nb e reduce dthroug hredundanc y o f sealin g mechanisms . Fo r instance , a singl e sea l ma y emplo y a packe dsea l a s a n auxiliar y

sealin g mechanis m

t o reduc e fugitiv e emissions . O r th e same purpos e migh t b e jus t a s easil y accomplishe dwit hsome dua l mechanica l sea l arrangement s (eithe r back-to-bac k o r tandem. ) A s show ninFigur e 2-4 , the dua. 1 mechanica l seal s i nbot harrangement s for m a cavity . Inth e back-to-bac k arrangement , a barrie r flui dcirculate s betwee nth e tw o seals . Wit hth e barrie r flui dpressur e maintaine dabov e th e pum p operatin g pressure , an y leakag e i s acros s th e inboar dsea l fac e int o th e proces s flui d an

d acros s th e outboar dsea l fac e t o th e atmosphere . Th e tandem arrangemen t basicall y ha s a singl e sea l backe du pb y anothe r singl e seal ; bot h seal s ar e mounte d facin g th e sam e direction . Th e sea l flui d(als o referre dt o a s th e buffe r o r barrie r fluid ) i s circulate dthroug hth e spac e betwee nth e seals . An y

proces s fluid s tha t ma y lea k int o th e barrie r flui dacros s th e inboar d sea l interfac e ma y b e remove dwit hth e barrie r flui do r degasse di na reservoir . Th e degasse d material s coul dthe nb e treate di na contro l system . I ngeneral , mechanica l seaT s hav e th e advantag e o f improve dsealin g characteristic s an

d auxiliar y

contro l fo r VO C th-a t ma y lea k int o th e barrie r flui d system . However , repai r o f mechanica l seal s ca nb e bot hcostl y an d time consuming . T o eliminat e a lea k fro m a pum pequippe dwit ha mechanica l seal , th e pum p mus t b e take noff-lin e an d dismantle dt o permi t repai r o r replacemen t
o f th e seal . Additionally , car e mus t b e exercise dt o minimiz e emission s resultin g fro

m dismantlin g th e pump . I nadditio nt o thes e pum ptype s an

d sea l designs , ther e ar e severa l type s o f sealles s technolog y available . Thre e design s hav e bee napplie di nth e chemica l industr y

wher e leakag e canno t b e tolerated . Th e canned-moto r pum pi s a shaftles s desig ninwhic hth e pum pbearing s runinth e proces s fluid . Th e moto r roto r housin g and pum p casin g ar e interconnected . Diaphragm pump s eliminat e al l seal s an d packin g expose dt o th e proces s flui dthroug hth e us e o f a flexibl e diaphragm (constructe do f metal , rubber , o r plasti c material ) a s th e drive r fo r movin g th e fluid . Magnetic-driv e pump s als o hav e n o seal s in contac t wit hth e proces s fluid ; th e impelle r i nth e pum pcasin g i s drive nb y



### 2-8P.2 9

POSSIBL E LEA K INTO SEALIN G FLUI D
FLUI D EN D SEA L LIQUID
. I N (BOTTOM)

£

PRIMAR Y SEA L SECONDAR Y SEA L 

### FIGUR E 2-4a

. DIAGRA M O F A DOUBL E MECHANICA L SEA L

(BACK-TO-BAC KARRANGEMENT ) GLAN D PLAT E

FLUI D EN D

PRIMARY SEA L BUFFER-LIQUI D OU T I N (TOP ) (BOTTOM )

GLAN D PLAT E

SECONDARY SEA L 70-1767- 1


### FIGUR E 2-4b

. DIAGRA M O F A DOUBL E MECHANICA L SEA L

(TANDE M ARRANGEMENT )

2- 9P.3 0



### a nexternally-mounte dmagne t couple dt o th e motor . Example s o f use s o f sealles s technolog y

fo r pump s includ e th e handlin g o f organi c solvents , organi c hea t transfe r liquids , toxi c o r hazardou s materials , an dexpensiv e materials .
2. 3 COMPRESSOR S
Compressor s provid e motiv e forc e fo r transportin g gase s throughou t a proces s uni t i nmuc hth e same manne r tha t pump s ar e use dt o transpor t liquids . Compressor s ar e drive nwit hrotatin g o r reciprocatin g shafts . Thus , th e sealin g mechanism s fo r compressor s ar e simila r t o thos e fo r pumps ; tha t is , packe dan

dmechanica l seal s ar e th e design s primaril y used . Again , i t i s th e sealin g mechanis m

tha t i s th e potentia l sourc e o f fugitiv e VO C emissions . Th e mechanica l seal s use do ncompressor s reduc e bu t d o no t eliminat e leakag e o f th e proces s fluid . Th e type s o f seal s commonl y use do ncompressor s include :

- Labyrinth , comprise do f interlockin g teet ht o restric t flow ;

- Restrictiv e carbo nrings , comprised'o f multipl e stationar y carbo nrings ;

- Mechanica l contact , whic hi s simila r t o th e mechanica l sea l fo r pumps ; an

d

- Liqui dfilm , whic hemploy s anoi l fil m betwee nth e rotatin g shaf t andstationar y

gland .
Thes e mechanica l seal s ca nb e vente di nvariou s manner s t o a contro l devic e fo r eliminatio no f VO C whic hma y lea k fro

m th e process . Th e us e o f packe d seal s i s generall y

restricte dt o reciprocatin g compressor s wher e mechanica l sea l design s canno t b e used . Leakag e o f VO C t o th e atmospher e fro m compresso r seal s ca nb e detecte db y instrumen t monitorin g a t th e seal . Repai r o f mechanica l seal s require s removin g th e compresso r fro m service . Sinc e compressor s i nth e SOCM I d o no t typicall y

hav e spares , immediat e repai r ma y no t be practica l o r possibl e

2-1 0P.3 1

withou t a proces s uni t shutdown . Ther e ar e optiona l contro l technique s tha t
ar e considere deffectiv e mean s o f controllin g emission s fro m mechanica l seal s o ncompressors . On e exampl e i s ventin g the barrie r flui dsystem o r th e sea l t o a contro l system

(fo r example , a close dven t system connecte dt o a contro l device) . » Leakag e fro

m packe dseal s ma y

b e reduce db

y tightenin g th e packin g gland . Figur e 2- 5 show s a typica l arrangemen t o f a singl e stag e reciprocatin g compressor . Onsome reciprocatin g design s (particularl y newe r compressors) , th e distanc e piec e betwee nth e compresso r cylinde r an dth e driv e crankcas e can b e vente dt o a contro l devic e t o trea t an y "leakag e throug hth e packing . O n th e olde r designs , however , thi s practic e ma y no t b e possibl e withou t replacin g (o r possibl y recasting ) th e distanc e piec e t o accommodat e th e ven t lin e o r completel y

replacin g th e olde r compresso r wit ha newe r desig n incorporatin g a ven t lin e connection .
2. 4 RELIE F DEVICE S

Relie f device s ar e safet y device s commonl y

use dt o preven t operatin g pressure s fro

m exceedin g th e maximu m allowabl e workin g pressure s o f proces s equipment . Th e mos t commo npressur e relie f devic e i s a spring-loade dvalv e (a s show ninFigur e 2-6 ) designe dt o ope nwhe nth e operatin g pressur e exceed s a se t pressure . Th e pressur e relie f valv e (PRV ) i s constructe ds o tha t i t wil l resea t afte r th e operatin g pressur e ha s decrease dt o a leve l below the se t pressure . Leak s o f VO C fro

m relie f device s occu r throug hth e valv e seat . Basicall y tw o mechanism s ar e cite dfo r relie f devic e leaks : (1 ) leakag e resultin g fro m imprope r reseatin g o f th e valv e afte r a releas e an d(2 ) leakag e resultin g fro m proces s operatio na t o r nea r th e valv e se t pressure . Th e latte r conditio ni s ofte nreferre dt o a s "simmering " o r "popping. " Ruptur e disk s (RDs ) ar e pressur e relie f device s tha t allo w no fugitiv e emissions , i f th e integrit y o f th e dis k i s maintained . Upo npressur e relief , however , th e dis k burst s an dth e proces s vent s directl y t o th e atmosphere

2-1 1Distanc e Piec e

r o i

Figur e 2-5 . Simpl e Single-stug e Reciprocatin g Compresso r, < • I P.3 3

f—•Ttmion-*dju«mtfi t

thimbt t

CONNECTIO N FO R

PRESSUR E GAUG E
* BL.EE O VALV E

RUPTUR E OlS K

FRO M SYSTE M
Figur e 2-6 . Pressur e Relie f Valv e in . a Basi c RD/PR V Combinat i



### io n

2-1 3P.3 4

unti l th e proces s pressur e ha s normalize dwit hth e atmosphere . Replacemen t o f th e ruptur e dis k restore s th e proces s t o a conditio no f no fugitiv e emissions . Ruptur e disk s shoul db e use di nconjunctio nwi.t

hrelie f valve s t o eliminat e potentia l fugitiv e emission s fro m relie f valves . Whe nmounte d. upstrea m o f a relief"valve , fugitiv e emission s ar e blocke dprio r t o th e potentia l lea k source , th e valv e seat . (Leakag e ma y occu r i f th e integrit y o f the-dis k i s no t maintained. ) A typica l arrangemen t o f a nRD/PR V combinatio n i s show ni nFigur e 2-6 ; suc hsystem s hav e bee nspecifie db y ASM E Code s whic h establis hth e desig nconstraint s an dcriteri a t o avoi dpotentia l safet y hazard s fro

m th e practice . Fo r instance , t o mee t ASM E requirements , th e spac e betwee nth e R D an

dth e PR

V mus t b e equippe dwit ha blee dvalv e an dpressur e gaug e tha t woul dindicat e an y pressur e build-u presultin g fro m a leakin g disk. 4
T o ensur e n o fugitiv e emission s t o th e atmosphere , th e ruptur e dis k mus t be replace dafter a

noverpressur e relief . On e optio ntha t accommodate s thi s procedur e consist s o f bloc k valve s mounte dupstream o f th e relie f devices . Thi s optio ni s onl y

possibl e wher e safet y rule s permi t th e us e o f a bloc k valv e i nrelie f lin e service . (Eve nwher e permitted , thi s practic e generall y include s provision s fo r lockin g th e bloc k valve°i nth e ope npositio ndurin g norma l operation. ) Th e othe r option s ar e dua l relie f valv e system s equippe d wit h3-wa y

valves . B

y usin g a 3-wa y

valve , a relie f system wil l alway s remai n i nservice , eve nwhe nreplacin g a ruptur e dis k onth e othe r relie f combination . A

numbe r o f possibl e configuration s ar e possible , fo r thi s option . Fo r instance , th e "primary " sid e (whic hwoul db e use dnormally ) coul d emplo y th e RD/PR

V combination , while , the."secondary " sid e (whic hwoul db e fo r back-u pservic e only ) coul dconsis t o f a ruptur e disk , a pressur e relie f valve , o r anothe r RD/PR V combination . Soft-sea t technolog y fo r relie f valve s consist s o f usin g a nelastomeri c 0-rin g t o provid e a nimprove dsea l whe nth e valv e reseat s afte r a nover pressur e release . Th e applicabilit y o f soft-sea t technolog y i s limite db

y material s compatibilit y an doperatin g conditions . Furthermore , soft-sea t technolog y

ha s no impac t onemission s fro m "simmering. " Fugitiv e emission s fro m al l mechanism s ca nb e stringentl y controlle db

y routin g th e discharg e o f th e pressur e relie f devic e t o a nappropriat e contro l

2-1 4devic e vi a a close dven t system . Th e mos t prevalen t exampl e o f thi s procedur e

i s th e us e o f a flar e header .
2. 5 OPEN-ENDE D VALVE S AN D LINE S 0 Open-ende dvalve s andline s ar e foun dthroughou t chemica l plants ; the y ar e generall y

drai nvalves , purg e valves , an dven t valves . Proces s fluid s m_y b e emitte dt o th e atmospher e throug hth e valv e sea t a s a resul t o f fault y seat s o r incompletel y close dvalves . T o preven t an y atmospheri c emission s fro m valv e sea t leakage , a pip e plug , cap , o r blfndflang e ca nb e installe do n th e ope nend . Anothe r optio ni s th e us e o f a secondvalve , insomethin g lik e a "block-and-bleed " arrangement . Usin g thi s arrangement , afte r th e valves^hav e bee nopene dt o allow flow o f proces s fluid , i t i s bes t t o clos e th e upstream valv e first . Inthi s manner , no proces s flui dcanbe trappe dbetwee nth e tw o valves . f

2. 6 SAMPLINGSYSTEM S -
Routin e periodi c check s o f proces s uni t operatio nar e ofte nmad e b y samplin g proces s stream s t o evaluat e th e performanc e o f reactors , distillatio n unit s an

dothe r operations , an dt o verif y

purit y an dcompositio no f feedstocks , intermediates , an dproducts . Proces s fluid s containe dinsampl e line s mus t b e purge dprio r t o samplin g t o obtai na representativ e sampl e fo r analysis . Th e purge dflui di s ofte nmerel y draine dont o th e groun do r int o th e sewe r drains , wher e VO C ma y b e release dt o th e atmosphere . Samplin g emission s ca nb e reduce db y usin g a close dpurg e samplin g system , designe dt o retur nth e purge dVO C t o th e proces s o r t o sen dth e VO C t o a close ddisposa l system (e.g. , a close dven t system connecte dt o a contro l device). ' Example s o f close dpurg e samplin g system s ar e show nschematicall y

in Figur e 2-7 . Inon e case , th e sampl e i s collecte da s a side-cu t stream fro m th e purg e stream , whic hflow s aroun da flow-restrictin g devic e (e.g. , a n orific e o r valve ) i nth e mai nproces s line . Inth e secon dexample , th e purg e i s directe dthroug hth e sampl e container . Thes e tw o example s ar e no t th e onl y

2-1 5

## -£ & PROCES S L-l ME
. «3 - 

# -c& PROCE.S S LIME
.



# X

i tr » 

# V SAMPLE
. COMTAIME R

SAMPLE
. COMTAIM6. R

Figur e 2-7 . Schematic s o f Closed Purg e Sampling System sP.3 7



### close d purg e samplin g system s possible

. Fo r instance , close d purg e samplin g ma yals o b e don e wit h partially-evacuate d sampl e containers

.

a 

### 2. 7 FLANGE S AN D OTHE R CONNECTOR S
Flange s and othe r connector s compris e th e singl e larges t clas s o f fugitiv e emissio n source s i n a proces s unit , i n term s o f tota l numbers
. Flange s ar e gasket-seale d junction s use d t o mat e pip e and othe r equipmen t suc h
a s valves , vessels , and pumps . Flange s ma yb e use d i n pip e size s 5 0 m m ( 2 inches ) o r greate r i n diameter

. Othe r connectors , suc h a s threade d connec tion s and nut-and-ferrul e connections , perfor mth e sam e functio n a s flanges , bu t the yar e use d primaril yo n lin e size s les s tha n 5 0 m mi n diameter

. Flange s an d othe r connector s ma ylea k VO C a s a resul t of :

- improperl yselecte d gaskets ; f

- poorl yassemble dflanges ; * '

- poorl yassemble d nut-and-ferrul e combinations ; p r

- cross-threade d pip e connections

.
Th e majo r caus e o f VO C leakag e fro mflange s and othe r connector s i s deformatio n o f sealin g surface s a s a resul t o f therma l stress
. VO C leak s fro m flange s an

d othe r connector s ca n b e determine d usin g instrumen t monitorin g techniques ; potentia l leak s ma yb e evidence d throug h othe r mean s suc h a s visual , auditory , o r olfactor ymeans . Tightenin g bolt s o n flange s i s on e metho d o f effectivel ysealin g VO C leak s fro msom e flanges
. Generally , however , flang e gaske t replacemen t o r correctio n o f a leakin g connecto r require s partia l o r complet e proces s uni t shutdown
. An d emission s fro mth e shutdow n o r repai r procedur e coul d eve n excee d th e long-ter memission s fro m th e 'lea k itself

.

2-1 7P.3 8

3. 0 EMISSION

FACTOR S

I nevaluatin g standard s o f performanc e o r eve nth e effectivenes s o f individua l program s o f emission s reduction , th e estimatio no f emission s fro m a give nsourc e i s a key element . Sourc e testin g fo r proces s emissio n sources , suc ha s reacto r vents , etc. , i s a relativel y .^trcightForward procedure . Estimatin g emission s fro m widel y disperse dfugitiv e emissio n source s canb e somewha t mor e difficult . On e o f th e firs t publishe d studie s o f fugitiv e emission s wa s conducte d insevera l petroleu

m refinerie s inth e Lo s Angele s Count y Ai r Pollutio n Contro l District . Th e estimate s o f thi s 1950' s join t stud y showe dtha t potentiall y

a larg e quantit y

o f hydrocarbon s coul db e los t t o th e atmospher e fro m variou s source s suc ha s valves , pum p an dcompresso r seals , coolin g towers , flanges , an

d pressur e relie f valves . I t was. , th e middl e 1970' s t*efare

_anothe r comprehensive - .^esogjt^Mr- t emissiofls^fj-^^prtr^e^. . reftnegt*? > fa s mad*.^- i }n_ tbfcS

y rawrv -"ife^pft ^ emission s measurements ^ wep e m«_e.;at v 1 £ refinerie s locate dthroug^ou * th e Unite d States . Emissio nfactors , screenin g relationships , an dcorrelation s wer e generate d fro

m dat a collecte d o

nvalves , flanges , pum pseals , compresso r seals , drains , an dpressur e relie f valves . Th e focu s o f thi s stud y wa s th e assessmen t o f atmospheri c emission s i npetroleu

m refineries , an d i t wa s surprisin g t o many peopl e t o fin

dtha t fugitiv e emission s wer e a majo r contributo r t o th e tota l ai r emission s fro m a refinery . Th e Refinin g Assessmen t Study wa s subsequentl y

use da s a primar y referenc e i

nstandard s developmen t activitie s b y EPA . Th e Refinin g Assessmen t Study

wa s the naugmente d wit hothe r informatio navailabl e i nth e literatur e an

d additiona l studie s o f fugitiv e emission s conducte d in chemica l proces s units .
3. 1 STUDIE S CONSIDERE D I N SOCM I EMISSIO N

FACTO RDEVELOPMEN T

Sinc e th e initia l fugitiv e emission s wor k don e i nth e 1950' s L A Count y studies , numerou s researc heffort s hav e focuse do nunderstandin g fugitiv e



### 3- 1P.3 9

emission s o f VOC . Studie s hav e considere dlea k frequency , lea k rate , emissio nfactors , method s o f lea k prevention , an dth e effectivenes s o f lea k preventio ntechnique s onreducin g th e numbe r o f leak s an dmas s emission s associate dwit hthem . Th e studie s liste di nTabl e 3- 1 ar e briefl y describe d below . Eac hstudy

I s summarize dwit hrespec t t o metho dan dresults . Actua l numerica l result s hav e bee nsummarize dinth e Additiona l Informatio n Documen t (AID ) fo r Fugitiv e Emissio nSource s o f Organi c Compounds .

3.1. 1 Petroleu

m Refinin g Assessmen t Study

Th e Refinin g Assessmen t Stud y wa s designe dt o provid e comprehensiv e emission s dat a fro

m a representativ e numbe r o f fugitiv e emissio nsource s i n eac hrefiner y

tested . I

neac ho f th e 1 3 refinerie s tested , equipmen t in severa l proces s unit s wer e sampled . A tota l o f 50 0 t o 60 0 emissio nsource s ineac hrefiner y

wer e screene do r sampled . T o eliminat e potentia l bia s fro m sourc e sele-ction , al l individua l source s wer e preselecte dfro m pipin g an

d instrumentatio ndrawing s befor e enterin g th e refinery . Unlik e previou s studies , dat a wer e gathere donscreenin g valu e (i.e. , portabl e organi c vapo r detecto r instrumen t reading ) an dmas s emissions . Thes e dat a permitte dth e developmen t o f averag e emissio nfactor s an dth e correlatio no f th e maximu m observe dscreenin g valu e an dth e measure d non-methan e lea k rat e o f VOC . Th e lea k frequencie s determine dfro m fiel d measurement s an

dth e averag e emissio nfactor s compute dar e show nin Tabl e 3-2 . Thes e result s serve da s th e principa l dat a agains t whic hothe r fugitiv e emission s wor k b y EPA woul db e compared . Th e Refinin g Assessmen t Stud y als o provide dsome othe r ver y importan t results . Th e onl y

equipmen t o r proces s variabl e foundt o correlat e wit h fugitiv e emissio nrate s wa s th e volatilit y o f th e stream

components . Thi s resul t le dt o th e separatio no f equipmen t componen t emission s b y service : gas/vapor , hydrogen , ligh t liqui dandheav y liquid . Thes e classification s hav e bee nuse di nmos t fugitiv e emission s standard s t o direc t effectivel y th e majo r effor t towar dequipmen t mos t likel y t pleak .



### 3- 2P.4 0

Tabl e 3-1 . FUGITIV E EMISSION S STUDIE S I N TH E AI D

Referenc e No . 6 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 19,2 0 Petroleu

m Refinin g Assessmen t Study Fou r Uni t EPA

Study EPA 6-Uni t Stud

y Du Pon t Stud

y Exxo nCyclohexan e Study EPA 24-Uni t Stud

y Evaluatio no f Maintenanc e fo r Fugitiv e VO C Emission s Contro l Analysi s o f Fugitiv e Emission s Dat a Revisio no f Emissio nFactors/SOCM I Processe s Germa nStudie s Unio nCarbid e Study Evaluatio no f Allie d HDP E Stud y Cok e Ove nBy-Produc t Recover y an d Ga s Plant s Studie s 

# 1

3- 3P.4 1



### TABL E 3-2 . LEA

KFREQUENCIE S AND EMISSION FACTORS : REFININGASSESSMEN T STUDY

Equipmen t Emissio nFacto r Percen t o f Source s Servic e kg/hr/sourc e >10,00 0 pp m

Valve s

Pum pSeal s

Compresso r Seal s

Pressur e Relie f Valve s 

### Ga s

LL b



### HL C



### L L

H L

Ga s
Ga s 0.026 8

0.010 9

0.0002 3

0.11 4

0.02 1

0.63 6

0.1 6 

### 1

0
1 1
0. 2

2 4

2
3 6

7
Flange s Al l 0.0002 5 0. 5
Open-Ende dLine s Al l 0.002 3 7. 7

Fro m Appendi xB o f th e Refinin g Assessmen t repor t (EPA-600/2-80-075C) . Referenc e 21 . b 

### L L - ligh t liqui dservice ; i.e. , compound s wit hvapo r pressur e greate r tha n kerosene . C 

### H L - heav

y liqui dservice ; i.e. , compound s wit hvapo r pressur e o f kerosen e an dlower .

3- 4P.4 2

3.1. 2 Fou r Uni t EP

A Studv 8

Althoug hdesigne dalon g th e same line s a s th e Refinin g Assessmen t Study , thi s stud y

conducte db

y EPA-IER L (RTP ) wa s to o limite dinscop e t o yiel dresult s wit hreasonabl e confidenc e interval s fo r mos t sourc e types . Th e mos t importan t resul t o f th e Fou r Uni t Stud y wa s tha t o f illustratin g th e nee dfo r mor e intensiv e samplin g an dscreening .
3.1. 3 EP A

6-Uni t Studv 9

Th e 6-Uni t Study

wa s th e nex t leve l intestin g o f fugitiv e emission s conducte db

y EPA . Fo r thi s study , lea k frequencie s (a s determine dusin g a portabl e organi c analyze r an dconsiderin g a 10,00 0 ppm v lea k definition )
wer e evaluate dfo r al l potentia l source s o na nindividua l componen t basis . Plan t personne l identifie dthos e equipmen t believe dt o handl e organics . And
n o attemp t wa s mad e t o segregat e equipmen t b y servic e (e.g. , ingas/vapo r service , i nligh t liqui dservice , etc.) . N o emissio nrat e measurement s wer e made , s o n o emissio nfactor s wer e determined .

3.1. 4 D uPon t Studv 1 0

E . I . duPon t d e Nemour s conducte da nindependen t surve y

o f tw o o f thei r proces s unit s t o evaluat e th e lea k frequencie s o f pump s an dvalve s an

dth e lea k rate s o f valves . A portabl e organi c analyze r (calibrate dt o hexane ) wa s use dt o identif y

leak s o f 1 0 pp

m o r greater . DuPon t evaluate dactua l lea k rate s ononl y

6- 8 valves . Th e stud y ha da limite ddat a bas e fo r pump s an d valve s andwa s restricte dt o two olde r proces s units . D uPont' s lea k definitio nwa s inconsisten t wit hEP A work . An dfinally , ther e wa s no determinatio no f anaverag e emissio nfactor .
3.1. 5 Exxo nCyclohexan e Study

Exxo nChemica l Compan y conducte da study

o f fugitiv e emission s source s a t it s Baytowncyclohexan e unit . Valve s wer e screene dusin g a soa psolutio n (soaping) ; pum

pseals , compresso r seal s an dsafet y

valve s wer e instrumen t 3- 5P.4 3

screene dusin g a nundefine dlea k definition . Valv e leak s wer e classifie da s small , medium , o r larg e fo r selectio nfo r mas s emission s sampling . Th e percentag e o f leak s an demissio nfactor s determine dfro m th e stud

y coul dno t be relate dt o EPA' s wor k du e t o th e inconsistencie s inlea k definition s betwee nth e two studies .
3.1. 6 EPA

24-Uni t Study 1 2

In1980 , EP A

coordinate da study o f 2 4 individua l chemica l proces s units . Th e proces s unit s wer e selecte dt o represen t a cross-sectio no f th e populatio nacros s SOCMI . Amon g th e chemica l compound s include di nth e surve y wer e acrylonitrile , ethylen e dichloride , formaldehyde , perchloroethylene , an dviny l chloride . Selection s o f equipmen t t o be screene dwer e mad e prio r t o screenin g activities ; screenin g wa s conducte db y two-perso nteam s Usin g portabl e organi c analyzers . Calibratio nwa s don e dail y a t a minimum . A

larg e numbe r o f th e followin g type s o f equipmen t wer e screene dinth e 2 4 unit s fo r determinatio no f lea k frequency : flanges , proces s drains , open-ende dlines , agitato r seals , relie f valves , valves , pum pseals , andcompresso r seals . Thes e source s wer e furthe r groupe db y th e chemica l phas e o f th e materia l bein g handled : ingas/vapo r service , i nligh t liqui dservice , an

dinheav

y liqui dservice .

3.1. 7 Maintenanc e Stud y

A stud y o f th e effect s o f maintenanc e o nemission s wa s performe d concurrentl y

a t si xo f th e unit s screene di nth e 24-Uni t Study . Thi s wor k yielde dquantitativ e estimate s o f lea k occurrenc e an drecurrenc e rate s an d
o f th e effect s o f maintenanc e o nfugitiv e emissions . Coinciden t wit hthes e estimates , correlation s o f screenin g value s an dlea k rate s wer e made . Th e Maintenanc e Study focuse do nga s valves , ligh t liqui dvalves , and ligh t liqui dpump s inthre e type s o f proces s units : ethylene , cumene , an d viny l acetate . Th e unit s selecte dwer e considere dt o b e representativ e o f th e leve l o f contro l existin g i nth e chemica l industry .



### 3- 6P.4 4

1 4 1 5 3.1. 8 Analysi s Repor t an dRevisio no f SOCM I Emissio nFactor s
Dat a gathere ddurin g th e 24-Uni t Study an dth e Maintenanc e Study wer e subjecte dt o a mor e in-dept hanalysis . Th e dat a analysi s task s include din th e repor t wer e generatio no f averag e emissio nfactors , analysi s o f lea k frequenc y

a s a functio no f proces s parameter s an dequipmen t design , analysi s o f th e impac t o f instrumen t respons e factor s o nlea k frequency , an danalysi s o f th e impac t o nmas s emission s o f lea k occurrenc e an drecurrenc e rates . Lea k frequencie s fo r th e variou s sourc e type s varie damon g th e 1 5 proces s unit s an

damon g sourc e types . Highe r lea k frequencie s wer e foundt o b e associate dwit hhighe r lin e pressures , whil e lin e temperatur e appeare dt o hav e n o consisten t effect . Averag e emissio nfactor s wer e develope dfo r ga s valves , ligh t liqui d valves , andligh t liqui dpump s i nth e thre e proces s uni t type s examine din th e Maintenanc e Study . Inthi s case , emissio nfactor s wer e generate donl y fo r thes e processe s sinc e th e lea k rate/screenin g valu e correlation s develope ddepen do

nproces s type . Thes e emissio nfactor s wer e late r revise d t o accoun t fo r dat a biasin g du e t o off-scal e instrumen t reading s an d maintenanc e effects . Th e value s determine dwer e generall y foun dt o be lowe r tha nth e averag e emissio nfactor s determine dfo r petroleu m refineries .
3.1. 9 Germa nStudie s o nFugitiv e Emission s

Fou r studie s conducte db y industr y

an dgovernmen t group s inWes t German y investigate dfugitiv e emission s an dmethod s o f preventionin chemica l an

dpetrochemica l plants . Th e source s studie dinclude dflanges , threade dconnections , compresso r seals , pum pseals , agitato r seal s an d valves . Fou r differen t method s o f lea k rat e determinatio no r estimatio n we'r e employed . Th e studie s wer e inconclusiv e i ngivin g th e quantitativ e dependenc e o f leakage s o nchemical , physical , an ddesig nparameter s o f sealin g elements . Insufficien t dat a wer e cite da s th e reason . Lea k rate s foundfo r th e source s investigate dwer e i ngenera l abou t 1/1 0 o f th e value s previousl y publishe dinth e literature . I t i s importan t t o not e tha t th e low value s represen t leakag e rate s fo r well-maintaine dfacilities . I naddition ,
3- 7

_______ __P_4 5

th e studie s note d tha t prio r t o an y directe dmaintenanc e activity , th e lea k rat e fo r valve s wa s 20 0 percen t o f th e publishe dvalue . Mos t o f thes e emission s wer e reduce d b y repai r o f a singl e larg e lea k prio r t o additiona l measurements .

0 1 7 3.1.1 0 Unio nCarbid e Study

Unio nCarbid e conducte d a stud y o f a singl e proces s uni t t o 1 ) fin d al l leakin g point s i nth e unit , 2 ) quantif y th e lea k rate s fo r thes e points , an d 3 ) develo p a statistica l fugitiv e emissid nsamplin g pla nfo r futur e work . Leak s wer e determine d usin g a portabl e organi c analyze r calibrate dwit h hexan e fo r a 1,00 0 ppm v lea k definition . A noveral l lea k frequenc y o f 6. 7 percen t wa s foun

d fo r th e 1,56 9 point s screened . Pum pseal s an

dopen-ende d line s demonstrate d th e highes t lea k frequencie s a t ove r 3 0 percent . Poin t lea k rate s wer e determine db y variou s mean s fo r al l source s determine d t o b e leakin g (i.e. , screenin g a t o r abov e 1,00 0 ppmv) . Th e metho d o f determinin g th e lea k rat e depende dupo nth e rat e o f leakag e (high ; medium ; low ) an

d temperatures . .Th e lea k rate s wer e no t classifie db y sourc e typ e (eg. , pum

p seal , valve , etc.) . Rather,,the y wer e reporte db

y th e degre e o r exten t o f leakage : (1 ) smal l lea k (0:00 1 - 0.0 2 lb/day) ; (2 ) we t surfac e (0. 1 - 0. 5 lb/day) ; (3 ) drippin g o r stron g unbearabl e odo r ( 1 - 2 0 lb/day) ; an

d (4 ) continuou s flo w (5 0 - 15 0 lb/day) . No lea k rate s wer e establishe d fo r source s screenin g les s tha n1,00 0 ppmv . Th e lea k rate s wer e no t use d indevelopin g EPA' s factor s sinc e the y coul dno t b e compare dt o dat a gathere d b

y EPA . I nit s recommendations , Unio nCarbid e cite ddevelopmen t o f a lea k rate/screenin g valu e correlatio na s a nimprovemen t i nestimatin g emissions . I naddition , th e wor k don e b y Unio nCarbid e recognize dthat , inorde r t o establis hlea k rate s fo r 1 3 equipmen t types , some 23,00 0 source s woul d have , t o be screene d an

d 1,00 0 lea k measurement s mad e t o obtai ndat a withi nth e 9 0 percen t level s o f confidenc e desired .



### 3- 8P.4 6

3.1.1 1 Analysi s o f Allie dHDP E Uni t Data 1 8

Kemro nEnvironmenta l Corporation , inconjunctio nwit hAllie dChemical , conducte da 10-mont hstudy o f flange s an

dvalve s i na ne w

hig hdensit y polyethylen e (HDPE)'unit . Basicall y focusin g onmaintenanc e effects , si x screenin g andemission s measuremen t test s wer e performe do nvalve s an

d flange s ove r th e cours e o f th e study . Screenin g wa s don e usin g a portabl e organi c analyze r calibrate dt o 1,00 0 ppm v hexane . (Unlik e th e EPA studies , a hig hconcentratio ncalibratio nstandar dwa s no t used , no r wa s calibratio n verifie da t th e completio no f dail y screening* . Whil e lea k rate s wer e determine dfo r source s screenin g a t 10,00 0 ppm v o r greater , thes e rate s ar e no t comparabl e t o averag e emissio nfactors . (Averag e emissio nfactor s conside r emission s fro m al l valve s acros s anentir e distributio no f screenin g values , no t jus t value s highe r tha n10,00 0 ppmv. ) Further , som e o f th e valve s sample dfo r lea k rat e hadbee nsubjecte dt o a directe d maintenanc e progra m

prio r t o sampling . Thi s actio nresulte dinlowe r emission s tha nwoul db e expecte dinth e absenc e o f an y maintenanc e efforts .

3.1.1 2 SCAQM D Study 2 2

T o evaluat e th e effectivenes s o f fugitiv e emissio ncontro l regulations , EPA conducte da surve y

o f two refinerie s i nth e Sout hCoas t Ai r Qualit y Managemen t Distric t (SCAQMD ) inCalifornia . Accessibl e valves , pumps , agitators , open-ende dlines , drains , an drelie f valve s i n8 proces s unit s wer e screene dusin g EP A Referenc e Metho d21 / No flange s wer e surveye d durin g thi s study . Sinc e thi s wa s a maintenance-oriente dstudy , n o mas s emissio nrat e measurement s wer e made .



### 3- 9P.4 7

3.1.1 3 Cok e Ove nBy-Produc t Recovery 1 9 an dGa s Plan t Studies 2 0

Thre e cok e ove nby-produc t recover y plant s wer e teste dfo r fugitiv e benzen e emissions . Sourc e screenin g wa s don e wit htw o differen t type s o f portabl e organi c analyzers . Emission s dat a gathere dwer e categorize d accordin g t o sourc e typ e and stream benzene , content , bu t n o distinctio no f servic e wa s made . Non-methan e hydrocarbo nemissio nfactor s wer e generate d fo r valves , pum

p seals , an

d exhauster s (i.e. , compressor s mainl y inhydroge n service) . A tota l o f si xnatura l ga s processin g plant s wer e teste d b y EPA an dthe 2 3 America nPetroleu

m Institut e (API) . Screenin g wa s don e b y bot hsoapin g
and portabl e organi c analyzers . Lea k rat e dat a collecte ddurin g th e combine d stud

y wer e use d t o estimat e lea k rate s fo r emittin g sources . Thes e result s wer e the napplie d t o th e populatio nt o estimat e th e averag e emissio n factor s fo r connection s an dflanges , open-ende dlines , pressur e relie f devices , valves , pum p seals , an

dcompressor seals .
3. 2 EPA' S CHOIC E O F DAT A FORSOCM I EMISSION

FACTOR S

EP A use d thre e majo r criteri a inevaluatin g dat a t o us e t o estimat e fugitiv e VO C emissions : 1 ) relevanc e t o fugitiv e emissions , 2 ) validit y o f th e testin g an

d analytica l procedures , an d 3 ) comparabilit y

t o othe r studie s t o allow validatio no f results . Th e studie s o f fugitiv e emission s summarize dabov e wer e evaluate d i n th e AI D wit hrespec t t o thei r relevanc e t o estimatin g fugitiv e emissio n factors . Fo r example , th e emissio nfactor s generate dinth e Maintenanc e Stud y wer e no t considere dth e highes t quality , bes t availabl e dat a o nmas s emissions ; estimatio no f emissio nfactor s wa s no t th e principa l purpos e o f th e Maintenanc e Study . Th e factor s wer e used , however , t o evaluat e th e result s o f th e emissio nfacto r estimate s made . • Th e second criterio nwa s use dt o eliminat e fro m consideratio ndat a tha t
wer e no t collecte d b y clear , consistent , acceptabl e tes t procedures . Fo r example , th e resul t o f studie s unde r scrutiny woul dnee dt o b e evaluate d wit hrespec t t o 1 ) ho w th e sample s wer e collected , 2 ) how th e measurement s wer e mad e (fiel d o r laboratory) , an d3 ) wha t typ e o f equipmen t wa s 3-1 0P.4 8

represente db

y th e reporte ddat a (onl y leakin g equipment , complete distribu tio no f equipment , etc.) . Thi s same sor t o f evaluatio nwa s neede dt o conside r difference s inlea k definition , metho do f determinin g leak s . (soaping , instrumen t screening) , an dmonitorin g instruments . Th e fina l criterio nwa s comparabilit y o f th e studies . Dat a fro m bot h th e Refinin g Assessmen t Study andth e combine dSOCM I studie s wer e gathere d i nth e sam e manne r usin g comparabl e instrumentatio nandlea k detectio n criteria . Statistically , th e dat a wer e handle dina simila r manne r in studyin g emission s andth e variou s effect s o f variou s parameter s on emissions . I t wa s onl y becaus e th e dat a fro m th e Refinin g Assessmen t Stud y andth e combine dSOCM I studie s wer e comparabl e tha t th e two studie s coul dbe evaluate dagainst'on e another . Mas s emission s dat a fro m th e Refinin g Assessmen t Study

an dlea k frequenc y

dat a fro

m th e SOCM I wor k wer e the n combine dt o for

m a singl e se t o f emissio nfactors . A s detaile dinth e AID , EPA determine dtha t th e bes t dat a availabl e fo r estimatin g emissio nfactor s fo r fugitiv e VO C emission s fro m SOCM I wa s fro

m th e Petroleu

m Refinin g Assessmen t Study an dfro m th e SOCM I 24-Uni t Study . Thes e studie s satisfie dth e thre e majo r criteri a fo r emission s estimat e data . EPA

compare dth e two dat a set s an d"acknowledge dther e wer e difference s tha t coul dno t b e explaine dconclusively . Th e Petroleu m Refinin g Assessmen t dat a wer e considere dth e bes t dat a o nmas s emission s fro m fugitiv e emission s sources . Th e Refinin g Assessmen t Study wa s planne d wit hestimatio no f VO C fugitiv e emission s a s on e o f it s objectives . VO C emission s dat a wer e gathere daccordin g t o equipmen t typ e an dservic e (i.e. , gas/vapor , ligh t liquid , heav y liquid) . Thes e dat a ar e considere d applicabl e t o VO C fugitiv e emissions , regardles s o f industry . Th e 24-Uni t Stud y bes t represente dth e lea k frequencie s tha t migh t b e expecte dacros s SOCMI . Therefore , fugitiv e sourc e emissio nfactor s fo r SOCM I wer e base don th e Refinin g Assessmen t andSOCM I emission s data , adjuste dusin g th e result s o f th e 24-Uni t Study . Thi s procedur e i s detaile di nSectio n3.4 . Severa l approache s t o estimatin g th e emissio nfactor s wer e considered . Th e estimatio nprocedur e presente dinth e AI O maintaine dconsistenc y wit h th e mathematica l procedur e followe dindevelopin g th e emissio nfactor s presente di nth e Refinin g Assessmen t Study an dSOCM I Maintenanc e Study . Befor e detailin g th e estimatio nprocedur e presente dinth e AID , th e method s 3-1 1followe d inth e Refinin g Assessmen t an d SOCM I Maintainanc e Studie s ar e presented .
3. 3 EMISSIO N

FACTO RDEVELOPMEN T

3.3. 1 Detaile d Procedura l Metho d

Th e developmen t o f averag e emissio nfactor s fo r individua l fugitiv e 2 1 emissio nsource s wa s lai d ou t inth e Petroleu m Refinin g Assessmen t Study . Sinc e then , embellishment s hav e bee nadde dt o thi s procedur e t o accoun t fo r censorin g o f dat a (i.e. , source s screene d a t th e maximu m instrumen t reading )
an d othe r samplin g effect s (eg. , pre-maintenanc e screening , post-maintenanc e screening , etc.) . Th e averag e emissio nfacto r i s no t merel y th e averag e o f th e mas s emission s measurement s mad e o nan y give ntyp e o f equipment . Th e proces s i s somewha t mor e involve d tha na simpl e average . Tw o type s o f fugitiv e emission s dat a wer e gathere dfo r th e developmen t
an d analysi s o f emissio nfactors . First , screenin g . dat a ( i .e. , concentratio nmeasurements ) wer e collecte d fo r a se t o f sources . Usin g thes e raw

screenin g data , empirica l cumulative " distributio nfunction s wer e generated . Th e empirica l distributio nfunctio nwoul dbe a key elemen t i

n estimatin g anaverag e emissio nfactor . I t wa s foundtha t th e cumulativ e distributio nfunction s wer e adequatel y describe db

y . a log-norma l distribution . Thi s led t o th e generatio no f modele dcumulativ e distributio n function s fo r sourc e screening . Thes e function s relat e th e screenin g valu e o f a sourc e t o a lea k frequency . Anexampl e o f a modele dcumulativ e distributio nfunctio ni s foun d i nFigur e 3-1 . Fro m suc ha figure , th e percentag e o f source s "leaking " (base d upo na selecte dlea k definition ) ca n b e established . Th e secon d typ e o f fugitiv e emission s dat a gathere dfo r averag e emission'facto r developmen t wa s mas s emission s data . Individua l source s wer e "bagged " an

d measure dfo r mas s emissio nrat e (lea k rate ) an dscreenin g value . Th e mas s emission s rat e dat a pair s wer e regresse dt o yiel dlea k rate/screenin g valu e correlation s fo r th e variou s sourc e types . A s wit han y experimenta l program , ther e wil l b e some degre e o f variabilit y in * th e dat a gathered , especiall y a s i t i s applie d t o estimat e othe r emission s fro m source s no t tested . Confidenc e interval s giv e a nindicatio no f th e rang e 3-1 23-13 P E R 10 0 C E N T 6 8 S C £ 6 8 E N 

## N « ° G G R 2 0 E A T E 0 R ,

Figur e tat____ta d raicao c o f touica a Scraanln g Craata r Tha n th a Salaoa d Sourc a

——»J X Coafldaac a Ltaic a

^ " * •**••-^^*** N *"*-^»_ ^

•. i
. i
. f ~~. ——— i 2 3 4 5 6 LOGI0COV A SCREENIN G VALUE )

t
3-1

. Cumulativ e Distribution : Cunien e Ga s Valves

. 0P.5 1

an dth e degre e ove r whic hth e result s ar e applicable . Th e numbe r o f dat a pair s necessar y

t o develo pthi s correlatio ndepend s upo nth e confidenc e interval s desire di nth e fina l value . Fo r example , fo r th e 9 5 percen t confidenc e leve l currentl y use di nfugitiv e emission s work , 7 6 dat a pair s distribute dove r th e rang e o f screenin g value s foundar e neededt o generat e th e screenin g value/mas s emission s rat e correlatio nfo r valves . By combinin g thes e two dat a sets , cumulativ e mas s emission s distribution s wer e established . Th e lea k rate/screenin g valu e correlatio n (fro m mas s emission s data ) wa s applie dt o th e cumulativ e distributio n functio n(fro

m screenin g data ) t o result " ina cumulativ e mas s emission s distributio nfunctio nfo r eac hsourc e type . Figur e 3- 2 show s a nexampl e o f thi s distributio nfo r cumen e ga s valves . Th e cumulativ e mas s emission s distributio nyield s th e percentag e o f mas s emission s (o f a sourc e type ) associate dwit ha selecte dlea k definition . Thi s valu e i s importan t i n generatin g th e leakin g an dnon-leakin g emissio nfactor s discusse dinSectio n 3.3.3 . Th e generatio no f th e averag e emissio nfacto r mad e us e o f th e empirica l screenin g distributio ndat a an dth e lea k rate/screenin g valu e correlation . Usin g th e correlatio n(develope dfro m mas s emi-ssion s data) , lea k rate s wer e estimate dfo r al l source s tha t ha dbee nscreened . Th e su m o f th e individua l lea k rate s represente dth e tota l mas s emission s lea k rat e fo r th e clas s o f
source s bein g considered . Th e averag e emissio nfacto r wa s derive db y averagin g th e su

m ove r th e tota l numbe r o f source s tha t wer e screened . Th e resultan t averag e emissio nfactor , therefore , considere dth e entir e distributio no f source s (an dscreenin g values) . I t wa s no t merel y th e averag e o f measure dlea k rate s determine dfo r some source s ou t o f th e population . Becaus e th e resul t o f th e procedur e i s a naverag e emissio n factor , i t shoul donl y b e applie dt o population s o f sources , an dno t t o a

n individua l component .

3.3. 2 Statistica l Consideration s

O f course , i ngeneratin g emissio nfactor s andi nevaluatin g thei r quality , statistica l consideration s mus t b e made . Fo r example , ther e i s a

3-1 43-15.

• • •

»

P 10 0 R C N 8 0 T T 0 6 0 T A L 4 0 E M I | 2 0 I 0 N

. e

Figur e 2 . •-••_ . *" , T»-^5___ =
_ C - ^

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 

### 1 

# V

—Eetlaate d Percen t o f Tota l
. \

~ Maa

a Ealaalon a Attributabl e . V t o Suurce a Wit h Screenin g V Value a Greate r Tha n th e M \ Selecte d Valu e \\ i

—9_ Z Confidenc e Llalt e VL \ \ l 

### 1 « \
t *,*.^.*.** \ I I 2 3 4 S 6

.

LOGI0COV A SCREENIN G VALUE )

• I

1-2

. Cumulativ e Mas s Emission s Distribution : Cumen e Ga s Valves

. -

-P.5 3



### minimu m numbe r o f dat a pair s (screenin g valu e an dmas s emissio nmeasurement ) require dt o generat e a statisticall y vali dscreenin g value/lea k rat e correlation . An dth e numbe r o f dat a collecte di nth e screenin g surve y o f an y populatio no f source s wil l hav e a direc t impac t o nth e confidenc e interval s associate dwit hth e modele dresults . Fro m th e previou s discussio nonth e emissio nfacto r developmen t procedur e use d1nth e Refinin g Assessmen t an dth e SOCM I Maintenanc e Studies , thre e model s ar e necessar y t o generat e averag e emissio nfactors . Th e screenin g valu e distributio ni s firs t modele dt o a log-norma l distributio n fo r source s screenin g a t mor e tha n1 0 ppmv . Th e confidenc e interval s fo r th e cumulativ e functio nar e evaluate dusin g th e publishe dvalue s fo r th e Binomina l Distribution . A t th e 9 5 percen t confidenc e level , th e estimate d A 

### cumulativ e percen t leakin g (p ) i s give nas :

i ± 1.9 6 [ p( 1 - p)/nl 1 / 2


### wher e ni s th e numbe r o f screenin g value s fo r th e particula r sourc e typ e unde r consideration . Fro m thi s equation , i t i s eviden t that , sinc e th e widt ho f th e confidenc e interva l varie s wit hth e invers e squar e roo t o f th e numbe r o f source s screened , a large r populatio no f screene dsource s yield s a smalle r confidenc e interval . Next , th e screenin g value/lea k rat e correlation s shoul db e considered , agai nwit hrespec t t o th e confidenc e interval . Lea k rate s ar e modele dina log-lo g relationshi passumin g a binomia l distribution , accordin g to :

Lo g (lea k rate ) °

@+{ l (log(screenin g value) ) + Z (standar derror )

where : a

, p-= » mode l parameters ; Z ° standar dnorma l random number ; an

dstandar derro r i s associate dwit hth e individua l predicto r equation . Again , publishe dBinomia l Confidenc e Interva l table s ar e use dt o generat e th e confidenc e interval s aroundth e averag e o f th e lo g (lea k rate ) estimates , (y) . Fo r example , th e valu e a t th e lowe r confidenc e interva l is :

3-1 6P.5 4

C ] - y

- 2.2 4 [s 2 /(n-r)] 1 / 2
2 where : s - varianc e o f th e estimate ; an d (n-r ) • numbe r o f leakin g sources .
Th e equatio nshow s th e effec t o f th e numbe r o f dat a point s inth e surve y o n th e siz e o f th e confidenc e interval . Durin g studie s o f fugitiv e emission s inOn-Shor e Ga s Productio nunits , a minimu m o f 7 6 dat a pair s wer e necessar y t o develo pth e screenin g value/lea k rat e .correlatio nwithi nth e 9 5 percen t 2 4 confidenc e interva l require do f th e fina l emissio nfactor . Th e fina l confidenc e interva l value s fo r th e emissio nfacto r ar e actually th e produc t o f th e valu e fo r th e (bias-corrected ) lea k rat e estimat e (show

nabove ) an

dth e valu e fo r th e percen t o f source s leaking . Th e confidenc e interval s fo r percen t o f source s leakin g ar e obtaine db y iterativ e solutio no f summatio nserie s equations . Fo r example , th e lowe r confidenc e limit , P. , shoul dbe determine dfrom : 

# J
. (? ) p 

# i (1 

# " 

# V " *



# '

where : (l-a ) represent s th e confidenc e level , ni s th e numbe r o f source s screened , an

dk i s th e numbe r o f leakin g sources . A s th e numbe r o f source s screene dincreases , th e confidenc e leve l increase s an dth e confidenc e interva l narrows . This.i s vividl y illustrate dinFigur e 3- 3 whic hshow s 9 5 percen t confidenc e interval s fo r a cumulativ e distributio nfunction , assumin g 10 0 an

d1,00 0 components .

3.3. 3 Leak/No-Lea k Approac h

Th e leak/no-lea k approac ht o estimatin g emissio nfactors , a s presente d inth e AID , i s a

nextensio no f th e complicate dproces s describe dabove . Th e expande dproces s consider s a lea k rate/screenin g valu e correlatio n integrate dove r a continuou s distributio nfunction ; th e leak/no-lea k approac hinstea dassume s onl y two emissio nrate s an dtw o populations : source s tha t "leak " (wit hscreenin g value s greate r tha no r equa l t o

. 3-1 7I C O M



### 3

M i M i

M i M i 

### 2 3 a » — aPerctnt 10 0
9 0
8 0

7 0

6 0

S O
4 0

3 0

2 0
10
0 -i~iVC_!*f' —_Z__^~_T—

__ .

———— —Estlnta d Par-can t o f \ » . \ \ Tota l Mat

s Eaission s \

\

N \ \ ' * \\
. ———-90 X Confidence Intarva l N \ \ x x fo r Parcan C o f Eaission s v N fro a Total Populatio n o f \ \ \\ \ Valva l ( n - « ) •90 t Confidence Interva l fo r Porcan t o f Eaission s I n a (Uitdoa Ser_pl t o f 100 0 Valva l

- —- —90

% Confldanc a Intarva l fo r Percen t o f Eaission s i n a Randa a Saapl e o f 10 0 Va l va s \ \ \

\

\ 

# V \

••' 1 ' •••<

_ L I 2 34 5 1 0 S O 100 100 0 10.00 0 100.00 0 1.000.00 0 Screenin g Valu e (ppav ) (Loq 1 Q Scale )

Figur e 3-3

. Cumulativ e Distributio n o f Tota l Emission s b yScreenin g Value s

Compariso n o f Confidenc e Intervals

.10,00 0 ppmv ) an dsource s tha t d o no t lea k (wit hscreenin g value s les s tha n 10,00 0 ppmv) . Th e basi s o f thi s extensio ni s a s follows : whe na grou po f source s "leak " (i.e. , hav e a screenin g valu e > 10,00 0 ppmv),.the y lea k a t a certai n mas s emissio nrat e dn , th e average . Similarly , a s a group , source s screene d
a t les s tha n10,00 0 ppm v (i.e. , non-leakin g sources ) hav e o nth e averag e a certai nmas s emissio nrat e associate dwit hthem . Thus , th e overal l averag e emissio nfacto r fo r a populatio no f emissio nsource s consist s o f two components : leakin g sourc e emission s an dnon-leakin g sourc e emissions . I t i s importan t t o remembe r tha t fugitiv e emission s ar e found distribute dove r a wid e rang e o f screenin g values . Mas s emission s associate d wit hfugitiv e emissio nsource s ar e similarl y distributed . Therefore , onl y emissio nfactor s generate dusin g distributio ndat a ca nbe use dinestimatin g emission s fro

m equipmen t leaks . Finally , onl y thos e emissio nfactor s generate di nsuc ha manne r ca nb e use di nth e extende dprocedur e discusse d below . 3.3.3. 1 Generatio no f Leakin g an dNonleakin g Emissio nFactors . Leakin g an

dnon-leakin g emissio nfactor s ar e generate dusin g thre e data : (1 ) th e averag e emissio nfactor , (2 ) the'lea k frequenc y associate dwit hth e averag e emissio nfactor , an d(3 ) th e percen t o f mas s emission s associate d wit hleakin g sources . A s a nexample , conside r th e dat a fo r ligh t liqui d valve s i

nth e Refinin g Assessmen t Study :

Averag e Emissio nFacto r 0.010 9 kg/hr/sourc e Lea k Frequenc y

11 % Percent o f Mas s Emissions , Leaker s 86 %

Assumin g 1,00 0 valves , th e tota l mas s emission s woul db e 10. 9 kg/hr ; an d 11 0 valve s o f th e tota l 1,00 0 woul daccoun t fo r 8 6 percen t o f th e mas s emissions , o r 9.3 7 kg/hr . Sinc e thi s amoun t o f emission s woul db e shared , onth e average , b

y al l leakin g valves , th e individua l leakin g emissio n facto r woul db e (9.3 7 kg/hr)/(11 0 valves ) o r 0.085 2 kg/hr/source . Th e non-leakin g emissio nfacto r i s similarl y computed . Fo r thi s example , 89 0 valve s tha t ar e "non-leaking " accoun t fo r onl y 1 4 percent o f th e tota l

3-1 9

y UP.5 7



### emissions , o r 1.5 3 kg/hr . Thi s yield s a naverag e nonleakin g emissio nfacto r o f (1.5 3 kg/hr)/(89 0 valves ) o r 0.0017 1 kg/hr/source . Pu t i nmor e genera l terms , th e emissio nfactor s fo r leakin g source s (LEF ) an dth e emissio nfactor s fo r nonleakin g source s (NLEF ) wer e compute d accordin g t o th e followin g equations :

LE F ° OE F * PCM

an dNLE F = OE F « flOO-PCM ) PC L (10 0 - PCL )
where : LE F •**

- emissio nfacto r fo r leakin g source s NLE F ° emissio nfacto r fo r nonleakin g source s OE F ° overal l averag e emissio nfacto r PC M = percen t o f mas s emission s du e t o leakin g source s PC L •** • percen t o f source s foundleakin g
Th e leakin g an dnonleakin g emissio nfactor s generate db y thi s procedur e an

d presente di nth e AI D ar e show ninTabl e 3-3 . 3.3.3. 2 Computatio no f Averag e Emissio nFactors . Havin g compute d leakin g an

dnonleakin g emissio nfactor s i n'th e abov e manner , averag e emissio nfactor s ca nb e determine db y merel y applyin g a lea k frequenc y determine dfro

m fiel dstudies . Continuin g wit hth e exampl e fro m above , th e lea k frequenc y

fo r ligh t liqui dvalve s inSOCM I wa s foundt o be 6. 5 percen t o nt_he . averag e (base donth e 24-Uni t Study) . Fo r 1,00 0 valve s inligh t liqui dservice , anestimate d6 5 woul dlea k a t a rate , onth e average , o f 0.085 2 kg/hr/valve , o r 5. 5 kg/hr . Th e 93 5 valve s predicte dt o be no t leakin g woul daccoun t fo r a nestimate d0.001 7 kg/hr/valve , o r 1. 6 kg/hr . S o al l 1,00 0 valve s inligh t liqui dservic e would ! hav e a predicte dcomposit e lea k rat e o f 7. 1 kg/hr , fo r anaverag e emissio nfacto r o f 0.007 1 kg/hr/source . Thi s procedure , restate dbelow 1na mor e genera l form , ca nb e applie dt o a populatio no f source s t o determin e th e averag e emissio n facto r (AEF) , provide dth e lea k frequenc y o f th e populatio nha s bee n established .

AE F ° LE F * PC L + NLE F « (10 0 - PCL )

10 0
3-2 0P.5 8

. / -•FABL E 3-3
. LEAKIN G AN D NON-LEAKIN G EMISSIO NFACTOR S FO R

FUGITIV E EMISSION S (kg/hr/source )

Equipmen t
Valve s

Pum p Seal s

Compresso r Seal s
Pressur e Relie f Valve s Flange s Open-Ende d Line s Servic e 

### Ga s LL b


### HL C


### L L H L 

### Ga s Ga s -Al l Al l Leakin g

(>'10,00 0 ppm ) Emissio n Facto r
0.0451 a 0.085 2 0.00023 d
0.43 7 0.388 5 1.60 8 1..69 1 0.G37 5 0.0119 5 ' Non-leakin g

( < 10,00 0 ppm ) Emissio n Facto r
0.00048 3
0.0017 1 0.0002 3 0.012 0 0.013 5 0.089 4 0.044 7 0.0000 6 0.0015 0

a Th e leakin g an d non-leakin g emissio n factor s fo r valve s i n gas/vapo r servic e ar e base d upo n th e emissio n factor s determine d fo r ga s valve s i n ethylene , cumene , and viny l acetat e unit s durin g th e SOCM I Maintenanc e Study
. L L - ligh t liqui d service

. C H L - heav yliqui d service

. Leakin g emissio n facto r assume d equa l t o non-leakin g emissio n facto r sinc e th e compute d leakin g emissio n facto r (0.0000 5 kg/hr/source ) wa s les s tha n non-leakin g emissio n factor . .P.5 9

3. 4 EMISSIO N

FACTOR S PRESENTE D I N TH E AI D

Tabl e 3- 4 present s th e result s o f thi s estimatio nproces s fo r th e lea k frequencie s determine d inth e SOCM I 24-Uni t Study . A s th e AI D discussed , thes e lea k frequencie s wer e considere dt o be representativ e value s fo r a cross-sectio no f th e large , divers e industr y tha t i s SOCMI . Th e averag e emissio nfactor s compute d base donthes e lea k frequencie s wer e use dt o estimat e emission s fo r th e entir e industry . A s applie dt o th e entir e populatio no f source s i nth e industry , thes e "typical " averag e emissio n factor s wer e deeme d appropriat e fo r standards-settin g activities . Thi s wa s particularl y

tru e becaus e the y

wer e applie dconsistentl y t o differen t regulator y

alternative s t o arriv e at comparisons . EP A considere d th e variabilit y o f lea k frequenc y

inth e industry

i n developin g it s fugitiv e emissio nstandards . Th e extensio no f th e procedur e fo r generatin g emissio nfactor s consider s th e "typical " averag e emissio n facto r t o b e a functio no f lea k frequenc y considere dtypica l o f th e industry . Also , i nevaluatin g valv e standard s fo r low leak-frequenc y

plants , th e technica l analysi s include d emissio nfactor s tha t varie dwit hlea k frequenc y

fo r valves . Result s o f thi s analysi s provide dsuppor t fo r th e provisio ninth e SOCM I standard s allowin g annua l monitorin g fo r proces s unit s wit h2 percen t o r les s valve s leaking . Th e averag e emissio nfactor s give ninTabl e 3- 4 wer e derive di na straightforwar d manne r usin g th e leakin g an dnon-leakin g emissio nfactor s fro m th e Refinin g Assessmen t Study (derive di nth e manne r jus t discussed )
an d th e lea k frequencie s fro m th e SOCM I 24-Uni t Study . Ther e ar e tw o instance s wher e thi s approac hwa s no t used , however . Thes e tw o case s deserv e specifi c mention . First , th e emissio nfacto r fo r samplin g connection s i s base do nth e amoun t o f sampl e purg e an d no t o na field-measure demissio nfacto r lik e othe r sourc e types . I nessence , a samplin g connectio ni s considere deithe r "uncontrolled " (tha t is , th e sampl e purg e wa s assume ddraine dt o th e environment ) o r "controlled " wit hth e sampl e purg e collecte dan dreturne dt o th e proces s lin e o r dispose do f properly . Th e actua l valu e use dfor.th e emissio nfacto r i s base do nth e quantit y o f samplin g purg e reporte dfo r

3-2 2P.6 0

TABL E 3-4 . AVERAG E EMISSIO N FACTOR S FORFUGITIV E EMISSION S I N SOCMI '

Equipmen t Componen t , "Average " SOCM I Factor s kg/hr/sourc e
Pum pSeal s Ligh t Liqui d Heavy Liqui d Valve s Ga s Ligh t Liqui d Heav y Liqui d Compresso r Seal s Safet y Relie f Valve s Flange s Open-Ende dLine s Samplin g Connection s 

### Ga s 0.049 4 0.021 4

0.005 6 0.007 1 0.0002 3 0.22 8 0.10 4 0.0008 3 0.001 7 0.015 0

3-2 3P.6 1

2 5 1,00 0 barrel s o f refinin g throughpu t an dth e averag e coun t o f samplin g connection s reporte d fo r every 1,00 0 barrel s o f refinin g throughpu t capacity . Th e rati o o f thes e tw o value s yield s a

nemissio nfacto r of . 0.015 0 kg/hr/source * I t i s importan t t o emphasiz e tha t emission s fro m samplin g connection s d o no t includ e emission s throug hth e sea l o r ste m o f th e samplin g valve . Thes e emission s ar e considere dpar t o f the emission s fro m th e valv e an

d open-ende d lin e categories . Th e second cas e worth y p f specifi c mentio ni s th e emissio nfacto r fo r valve s i nga s service . Afte r computin g average , emissio nfactor s usin g the Refinin g Assessmen t leakin g an d non-leakin g emissio nfactors , a compariso n wa s mad e wit hth e value s determine dfo r th e thre e equipmen t type s in ethylene , cumene , an d viny l acetat e proces s unit s presente dinth e SOCM I Maintenanc e Study . Fro m thi s comparison , th e emissio nfacto r fo r ga s valve s calculate d fro

m th e Refinin g Assessmen t dat a appeare ddifferent fro m the SOCM I values. . Th e fou r emissio nfactor s fo r ga s valve s determine dfo r petroleu m refining , ethylen e units , cumen e units , an dviny l acetat e unit s wer e the ncompare d visuall y a s i nFigur e 3-4 . Th e confidenc e interval s fo r th e SOCM I ga s valv e emissio nfactor s ar e much-narrowe r tha nthos e fo r the refinin g emissio nfactor . Furthermore , ther e i s almos t n o overla pbetwee n th e SOCM I confidenc e interval s an d thos e fo r petroleu m refining . Thi s comparativ e analysi s indicate s tha t (1 ) th e SOCM I ga s valv e factor s ar e different fro

m th e facto r fo r petroleu m refinin g an

d(2 ) th e SOCM I ga s valv e factor s ar e bette r estimator s o f SOCM I ga s valv e emissions . A s a resul t o f thi s comparativ e analysis , new leakin g an

dnon-leakin g emissio nfactor s fo r SOCM I ga s valve s wer e computed , base do ndat a fro

m th e SOCM I Maintenanc e Program . Th e fina l value s use di nformin g th e averag e emissio nfacto r fo r SOCM I ga s valve s were :

- 0.045 1 kg/hr/leakin g sourc e an d

- 0.0004 8 kg/hr/nonleakin g source .
Th e factor s fo r valve s an d pump s inligh t liqui dservice , show ninFigur e 3-5 , wer e no t found t o b e different . Therefore , th e emissio nfactor s develope d durin g th e Refinin g Assessmen t Study (being base dupona mor e substantia l dat a base ) wer e use d a s th e basi s fo r leakin g an dnon-leakin g sourc e emissio nfactors . 3-2 4P.6 2



### 0.05 0

0.04 0

. .
u

_ .

_ 3 o SA ***- ^ -. 

### ^ 0.03 0

._

_c

- • a '-. -r O »• - + J c < J o IQ U u . 

### e g 0.02 0 o as (/ > sn



### 0.01 0 Petroleu m Refinin g

Cumen e

Viny l Acetat e Ethylen e

1 5
Lea k Frequenc y

(10,00 0 ppm) , %

Figur e 3-4 . Compariso no f Emissio nFactors : Ga s Valves .

3-2 592- e

Emissio n Factor , kg/hr/sourc e (95 2 confidance )
o b 3 © b ro O o b s

£ • : rs :

3

_ _

o b

Emissio n Factor , kg/hr/scurc e (95 S confidence ) o b o

o o r o O

..s t o. — _ _ c a
3

_ 3

O
• c

= 3

_ T< T

E9 dP.6 4

Thes e "typical " averag e emissio nfactor s presente dinTabl e 3- 4 woul d als o b e appropriat e fo r us e inestimatin g emission s fo r proces s unit s wher e n o additiona l dat a ar e available . Take nona nindividua l basis , th e factor s themselve s represen t a hypothetica l "average" , no t necessaril y an y specifi c uni t o r process . Give ndat a ona specifi c proces s unit , averag e emissio n factor s coul db e generate dusin g th e procedur e illustrate dabov e fo r th e averag e SOCM I factors . Fo r example , assume a proces s uni t ha s bee nsurveye d fo r leak s (source s wit hscreenin g value s > 10,00 0 ppmv ) an d4 percen t o f ligh t liqui dvalve s wer e determine dt o be leaking . The na naverag e emissio n facto r fo r tha t uni t coul db e compute da s follows :

AE F - 0.085 2 * (0.04 ) + 0.001 7 * ( 1 - 004 )

= 0.005 1 kg/hr/sourc e

Th e concep t o f a

nemissio nfacto r tha t varie s wit hlea k frequenc y i s als o consisten t wit hth e dat a gathere ddurin g th e SOCM I studies . Clos e examinatio no f Figur e 3-1 4 show s some relationshi po f lea k frequenc y an d averag e emissio nfacto r fo r ga s valve s inth e thre e proces s unit s studie din th e Maintenanc e Study . Furthermore , ther e i s wid e variatio ninproces s uni t type s acros s SOCMI , a s evidence dinTabl e 3- 5 b y th e variatio ninlea k frequencie s fo r th e proces s unit s i nth e 24-Uni t Study . Th e cause s o f suc h variatio nar e many , bu t includ e chemical s processed , proces s parameter s suc h
a s operatin g temperature s an dpressures , an

dth e safet y

an dmaintenanc e practice s a t a give nsite .

3. 5 EXAMPL E HYPOTHETICA L CAS E

Inthi s section , a

nexampl e o f estimatin g emission s fo r a hypothetica l chemica l proces s uni t wil l b e considered . Thi s cas e assume s tha t th e proces s uni t ha s bee nsurveye dinaccordanc e wit hReferenc e Metho d2 1 an d tha t th e lea k frequencie s hav e bee nestablished . Tabl e 3- 6 show s thi s hypothetica l proces s uni t an da procedur e fo r estimatin g emission s usin g dat a inthi s report . Th e firs t colum npresent s

3-2 7



### BU BP.6 5



### TABL E 3-5 . LEA

KFREQUENCIE S B

YPROCES S FO

REQUIPMEN T I

N 2 4 SOCM I UNITS 1 2

Proces s Viny l Acetat e Ethylen e Cumen e Acetone/Pheno l Ethylen e Dichlorid e Viny l Chlorid e Formaldehyd e Methy l Ethy l Keton e Acetaldehyd e Methy l Methacrylat e Adipi c Aci d Chlorinate d Ethane s Acrylonitril e 1,1,1-Trichloro ethan e 0

Valves , Ga s 

### 3. 7
14. 8 14. 1 

### 0 1. 0 7. 3 2. 4 9. 2 4. 5 0 0 0 2. 3

- Percen t

Valves , Ligh t Liqui d 

### 0. 4
23. 2 10. 5 

### 0. 3 1. 1 1. 0 0 5. 1 0. 5 0. 1 0 0. 6 0. 9 1. 1 L

- o f Source s

Pumps , gh t Liqui d 

### 4. 5 26. 3 16. 0 

### 2. 3 5. 2 10. 8 

### 0 3. 2 9. 4 4. 4

- 

### 8. 3 8. 2 10. 0 Leakin g

Flange s 

### 1. 0 5. 7 2. 9 0 1. 1 3. 2 10. 0 

### 0 0 0 0 0 0. 4 0 Open-Ende d

Line s 

### 3. 7
12. 8 

### 9. 1 1. 3 2. 8 5. 1 0 9. 9 5. 7 0. 3 0 1. 4 2. 7 1. 8

3-2 8P.6 6



### TABL E 3-6 . ESTIMAT E O F "UNCONTROLLED " FUGITIVE EMISSION S

FORA HYPOTHETICA L CAS E

Sourc e

Pum p Seal s Ligh t Liqui d HeavyLiqui d Valve s Gas/Vapo r Ligh t Liqui d Heav yLiqui d
Pressur e Relie f Valve s Gas/Vapo r Open-Ende d Line s Compresso r Seal s Samplin g Connection s Flange s Numbe r Screene d

4 7 3

62 5 118 0 6 4



### 3 1 278 4 7 0 288 0 Numbe r

Leakin g

3 1

1 9 1 3 0



### 1 9 0

- 

### 20 Percen t Leaking

6. 4 33. 3



## 3-° c l.l c 0



### 3. 2 3. 2 0

- 

### 0. 7 Compute d Emissio nFacto r kg/hr/sourc e

0.025 6 0.138 5

0.001 8 0.002 6 0.0002 3

0.097 8 0.0018 " 0.089 4 0.015 0 0.0003 2 Annua l

Emission s Mg/y r

10. 5 3. 6

9. 9 26. 9 0. 1

28. 2 

### 4. 1 3. 1 9. 2 8. 1

a 

### Base do nvalue s fro

m Table 3-3 , usin g AE F = (LE F * PC L + NLE F * (100-PCL))/100 . Assume s 8,76 0 hour s o f operatio nannually . Composit e percen t leakin g fo r valve s i s 1.8% . NOT E - I nthi s case , valve s woul donl y nee dmonitorin g annuall y t o ensur e les s tha n2 percen t leaking .

3-29P.6 7

th e numbe r o f source s identifie d i nth e proces s uni t fo r eac hsourc e type . Th e second colum

nshow s th e numbe r o f source s wit hscreenin g value s greate r tha no r equa l t o 10,00 0 ppm v (I.e. , leakin g sources) . The . resultin g percentag e o f source s leakin g i s show ni nth e thir dcolumn . Th e averag e emissio nfactor s fo r thi s hypothetica l proces s uni t ca nthe nb e compute d usin g th e leakin g an d non-leakin g emissio nfactor s foundinTabl e 3-3 . Fo r example , 6. 4 percen t o f pum p seal s i nligh t liqui d servic e wer e foundt o b e leaking . Usin g th e leak/no-lea k approach , th e unit-specifi c emissio nfacto r i s estimate d as :

(0.43 7 kg/hr/source)(0.064 ) + (0.01 2 kg/hr/source)( 1 - 0.064) ,

o r 0.025 6 kg/hr/source . Th e tota l estimate demission s fo r pump s inligh t liqui d servic e woul d the nb e compute d b y multiplyin g th e unit-specifi c emissio nfacto r b

y th e equipmen t count . Th e las t colum ni nTabl e 3- 6 show s th e result s o f thi s proces s fo r th e hypothetica l unit . A furthe r extensio no f thi s procedur e woul db e t o examin e th e procedur e t o estimat e th e emissio nfacto r fo r a certai nspeci e i nth e line . Fo r example , conside r thi s same hypothetica l case,.wher e th e ligh t liqui dpumpe d containe d 2 0 percen t o f compoun d A . Th e compoun dA emissio nfacto r fo r ligh t liqui d pump s i s easil y compute db

y applyin g th e weigh t percen t (2 0 percen t inthi s case ) t o th e emissio nfacto r generate dabove :

(0.20)(0.025 6 kg/hr/source ) = 0.005 1 kg/hr/source .
Emissio nfactor s calculate d i nthi s manne r coul dthe nb e applie dt o th e equipmen t count s (wher e th e materia l i nth e proces s lin e containe d2 0 percen t o f compoun d A ) t o estimat e emission s o f compoun dA .

3-3 04. 0 EMISSION REDUCTIO N

No singl e emissio nreductio ntechniqu e ca nbe use dfo r al l fugitiv e emissio nsources . Th e technique s applicabl e t o fugitiv e emissio nsource s rang e fro

m equipment*t o wor k practices . Th e variou s contro l technique s considere dwer e describe dbriefl y i nth e earlie r sectio nonfugitiv e emissio nsources . The y ar e covere dinthi s sectio ninth e contex t o f thei r emission s reductio npotential .
4. 1 OVERVIE W

O F TECHNIQUE S

Th e technique s use dt o contro l emission s fro m equipmen t leak s canbe classifie dint o tw

o categories : equipmen t an dwor k practices . A

nequipmen t contro l techniqu e mean s tha t som e piec e o f equipmen t i s use dt o reduc e o r eliminat e emissions . A commo nexampl e i s anadd-o ncontro l devic e suc ha s a n incinerato r tha t i s use dt o reduc e organi c emission s fro m a proces s vent . Fo r fugitiv e emissio nsources , equipmen t control s include : (1 ) leakles s technolog y

fo r valve s an

dpumps ; (2 ) plugs , caps , blinds , etc . fo r open-ende dlines ; (3 ) ruptur e disk s an dsoft-se-at s (O-rings ) fo r PRVs ; (4 ) dua l mechanica l seal s wit hnon-VO C barrie r fluid/degassin g ven t system s fo r rotar y equipment ; (5 ) close dloo psamplin g systems ; an d(6 ) enclosur e o f
sea l area/ven t t o a combustio ncontro l devic e fo r dynami c seals . Thes e equipmen t contro l technique s ca ngenerall y attai nu

pt o 10 0 percen t reductio no f emissions , dependin g upo nth e contro l efficienc y o f th e contro l device . Mechanica l seal s an dthos e technique s tha t rel y upo na combustio n contro l techniqu e hav e bee nassigne da noveral l contro l efficienc y o f 9 5 percent , whic hi s consisten t wit hth e efficienc y assigne dt o som

e typicall y applfe d recover y

techniques . Th e contro l technique s use dfo r th e larges t numbe r o f fugitiv e emission source s ar e wor k practices . Th e primar y wor k practic e applie d t o PRVs, . valves , pumps , an

dothe r source s i s lea k detectio nan drepai r o f sources .



### 4- 1P.6 9



### 4. 2 LEA KDETECTIO N

AND REPAI R(LDAR )

Th e emission s reductio npotentia l fo r LDA Ra s a contro l techniqu e i s highl y variabl e dependin g upo nsevera l factors . Th e principa l elemen t impactin g emission s reductio ni s th e frequenc y o f monitorin g (surveying ) source s fo r lea k detection . Fo r example , a monthl y monitorin g pla nwoul d typicall y

b e mor e effectiv e i nreducin g emission s tha na quarterl y monitorin g pla nsinc e leak s woul db e foun dan dcorrecte dmor e quickly . Som e characteristic s o f individua l source s als o affec t emission s reduction : leakin g emissio nfacto r (a s compare dt o th e nonTeakin g emissio nfactor) , lea k occurrenc e rate , lea k recurrenc e rate , an drepai r effectiveness . Gatherin g o f thes e dat a fo r valve s an dpump s throug hextensiv e fiel dtestin g wa s th e focu s o f th e SOCM I Maintenanc e Study . Usin g specifi c sourc e characteristics , a nevaluatio no f contro l effectivenes s ca nb e mad e fo r differen t monitorin g plan s usin g th e LDA R 2 7 Model . Th e mode l i s a se t o f recursiv e equation s tha t operate s o na n overal l populatio no f source s tha t ca nb e segregate dint o th e followin g subgroup s fo r an

y give nmonitorin g interval : (1 ) source s tha t lea k du e t o th e lea k occurrenc e rate ; (2 ) source s tha t leak*an dcanno t be repaire dbelow th e 10,00 0 ppm

v lea k definition ; (3 ) source s tha t leaked , wer e repaire d successfully , bu t leake dagai nsoo nafte r th e repai r (i.e. , lea k recurrence) ; an

d(4 ) source s tha t d o no t lea k (i.e. , thos e screenin g below th e 10,00 0 ppm

v lea k definition) . Th e relativ e number s o f source s i neac h subgrou pchang e wit heac hmonitorin g interva l step , base do nth e characteristic s fo r th e sources . Figur e 4- 1 show s thes e subgroup s an dho w the y ma y interac t accordin g t o th e individua l sourc e characteristics . Th e LDA RMode l als o ha s th e capabilit y t o examin e comple xmonitorin g plan s suc ha s th e pla npermitte db y EPA unde r it s fugitiv e emission s standar dfo r valve s i nSOCMI . Thi s pla nallow s quarterl y monitorin g o f al l valves , supplemente dwit hmonthl y monitorin g o f thos e valve s tha t leake dan d
wer e repaired .

4-2 .P.7 0



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Perhap s th e bes t wa y t o illustrat e th e LDA RMode l i s t o presen t a n example . Th e particula r exampl e considere dher e i s th e "typical " SOCM I uni t presente d ihth e AID . Tabl e 4- 1 show s th e input s use di nexaminin g a LDAR . progra m fo r valve s an

d pump s base donmonthl y monitoring . Th e inpu t value s wer e derive d primaril y fro m th e SOCM I Maintenanc e Study . Th e selectio no f
eac hinpu t valu e i s detaile di nth e AID . Th e LDA RMode l use dt o estimat e emission s reduction s give s incrementa l result s a s wel l a s result s fo r a program tha t ha s bee nestablished . Fo r th e example , onc e a monthl y monitorin g pla ni s i nplace , emission s reduction s o f 7 3 percen t an d5 9 percen t ca nb e expecte d fo r valve s i nga s an dligh t liqui dservices ; likewis e a 6 1 percen t reductio ni nemission s ca nbe achieve dfo r pump s i n ligh t liqui d servic e unde r a monthl y LDA Rplan . Tabl e 4- 2 present s th e result s o f LDA Rmodelin g publishe di nthe AI D fo r valve s an

d pump s i

nSOCMI . Th e tabl e present s result s fo r simpl e monthly , quarterly , semiannual , an dannua l monitorin g o f valve s an dpumps . Additionally , th e monthly/quarterl y hybri d program

allowe db

y EP A fo r valve s i s shown . Thes e result s show that , a s monitorin g frequency , i s increased , th e anticipate d emission s reductio nincreases . Further , th e result s indicat e some instance s wher e ther e i s n o positiv e effec t i nreducin g emission s du e t o monitorin g an d repai r onto o infrequen t a schedule . Suc h results , however , ar e subjec t t o interpretatio nfo r specifi c case s sinc e the y ar e base d o

n"average " inpu t value s fo r anentir e industry . Th e abilit y

t o mode l th e result s o f LDA Rprogram s provide dth e mean s t o examin e alternativ e standard s fo r valves . Th e LDA RMode l wa s use dt o conside r monthl y

LDA Rprogram s fo r proces s unit s exhibitin g low lea k frequencies . Wit hdecreasin g lea k frequency , ther e i s a nassociate ddeclin e i nth e averag e emissio nfacto r an demission s reduction . Couplin g thi s informatio nwit hth e cost s o f th e LDA Rprogram , ananalysi s o f th e resultan t
cos t effectivenes s value s le d t o th e selectio no f 2 percen t leakin g as-th e performanc e limit . Thus , proces s unit s wit hlow Tea k rate s (an

dlow lea k frequencies ) wer e give na specia l provisio ni nth e NSP S fo r SOCM I fugitiv e VO C emissions .



### 4- 4P.7 2



### TABL E 4-1 . LDA

R

Inpu t Emissio nfactor , kg/hr/sourc e Occurrenc e rat e

Initia l lea k frequenc y Fractiona l emissio n reductio nfrom unsuccessfu l repai r INPUT S AN D COMPUTE D REDUCTION S

» 

### Descriptio n Initia l averag e emissio n facto r fo r al l source s Fractio no f nonleaker s tha t becam e leaker s ove r th e " interva l Fractio no f source s leakin g a t initiatio no f LDA

Rprogram Reductio nfro

m source s no t repaire dbelo w

10,00 0 ppm

v FO RSOCMI/MONTHL YMONITORING



### Valves , Gas/Vapo r
0.005 6

0.01 3

0.11 4

0.6 3 Valves ,

Ligh t Liqui d 0.007 1

0.01 3

0.06 5

0.6 3 Pumps ,

Ligh t Liqui d 0.049 4

0.03 4

0.08 8

0

Fractiona l emissio n reductio n fro m successfu l repai r Fractio n o f un successfu l repair s

Fractio n o f earl y failure s

Turnaroun d frequency , month s Reductio nfro m source s ; •.;.••:•:_

• 0..9&- - < repaire d below

10,00 0 ppm

v

Source s tha t leake d bu t * 0.1 0 attempte d repai r belo w 10,00 0 ppm

v faile d
Source s repaire d belo w0.1 4 10,00 0 ppmv bu t leake d withi n th e nex t interva l Perio d betwee n plan t 2 4 shutdown s 0.9 8

0.1 0

0.1 4



### 2 4 0.97 2



### 2 4

EMISSION REDUCTION

COMPUTED : 0.7 3 0.5 9 0.60 8



### 4- 5P.7 3



### TABL E 4-2 . LDA

RMODE L RESULT S FO

RSOCM I VALVE S AN D PUMP S

0 Monitorin g Interva l
Monthl y Monthly/Quarterly 3 Quarterl y Semi-annua l
Annua l 

### Va l ves , Ga s
0.7 3 0.6 5 0.6 4 0.5 0 0.2 4 Sourc e Tvo e

Valves , Ligh t Liqui d
0.5 9 0.4 6 0.4 4 0.2 2 (0.19 ) Pumps ,

Ligh t Liqui d
0.6 1

- 0.3 3 (0.076 ) (0.80 )

a 

### Monthl y monitorin g wit hquarterl y monitorin g o f "lo

w leak " components . NOTE : Number s i

nparenthese s indicat e a negativ e contro l efficiency . Negativ e number s ar e generate dwhe nth e occurrenc e rat e fo r th e monitorin g interva l exceed s th e initia l lea k frequency . Negativ e result s ar e subjec t t o inter pretatio nan

d ma y no t b e meaningful .

4- 6P.7 4



### 4. 3 SUMMARYO F EMISSION REDUCTION S
Emission s reduction s fo r fugitiv e emission s contro l technique s ca nb e extremel y

variable , particularl y fo r wor k practice s lik e lea k detectio nan d repai r programs . Interm s o f standard-settin g activities , criteri a fo r selectio nq f a give ncontro l techniqu e o r a particula r leve l o f contro l (eg. , monitorin g interva l o f a lea k detectio nan drepai r program ) canb e quit e different . Fo r example , th e criterio nusedi nestablishin g th e bes t demonstrate dtechnolog y (BDT ) fo r NSP S ma y

no t necessaril y

b e equivalen t t o th e choic e insettin g th e reasonabl y availabl e contro l technolog y (RACT ) presente dincontro l technique s guideline s (CTG ) document s use db y States . Thes e two level s o f contro l ar e compare di nTabl e 4- 3 fo r VO C equipmen t ;leak s (fugitiv e emissions ) fro m SOCMI ; th e associate dcontro l effectivenes s value s ar e als o presented . " 4

4- 7TABL E 4-3 . CONTRO L LEVEL S FO R SOCM I FUGITIV

E EMISSIONS : NSP S AN D CT G

Sourc e 

### _£IS

_ J4SES

_
Contro l Techniqu e Percen t Contro l Contro l Techniqu e Percen t Contro l
Pumps . Ligh t Liqui d Quarterl y lea k detection an

d repai r 3 3 Monthl y lea k detectio n an

d repai r 6 1
Dua l mechanica l seal/heav y liqui d 10 0 barrie r flui d

Valves . Ga s Ligh t Liqui d Quarterl y lea k detection an

d repai r 6 4 Monthl y lea k detectio n an

d repai r 7 3

5 9

Pressur e Relle f Valves . Ga s
Open-Ende d Line s

Compressor s
Samplin g Connection s Quarterl y lea k detection an

d repai r

Plugs , caps , blinds , etc .
Quarterl y

lea k detection an

d repai r

— 4 4

10 0

3 3

- Ruptur e disk , sof t seat s (O-rlngs) . 10 0 ven t t o contro l devic e
Plugs , caps , blinds , etc . 10 0

Sea l enclosed/vente d t o contro l devic e 10 0

Close d purg e sampling 10 05. 0 LIST S O F REFERENCE S

1 . U.S . Environmenta l Protectio nAgency . VO C Emission s i nSyntheti c Organi c Chemical s Manufacturin g Industr y - Backgroun dInformatio nfo r Promulgate d Standards . Researc hTriangl e Park , N.C . Publicatio nNo . EPA-450/3-80-033b . Jun e 1982 . 0 ' 2 . Mem o fro

m Stelling , J.H.E. , Radia nCorporation , t o SOCM I Docket . Novembe r 1 , 1982 . 1 0 p . Estimat e o f VO C Emission s fro m SOCMI . 3 . Honerkamp , R . L . an dM . L . Schwendemen . (Radia nCorporation. ) Evaluatio no f Maintenanc e Effec t onFugitiv e Emission s fo r Refinerie s in th e Sout hCoas t Ai r Qualit y Managemen t district . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/7-82-049 . Jun e 1982 . 4 . America nPetroleu m Institute . Guid e fo r Pressur e Relie f an dDepressurin g Systems . AP I R P 521 , Firs t Edition . Septembe r 1969 . 5 . Palmer , R . K . Hydrocarbo nLosses , fro m Valve s an

dFlanges . Join t District , Federa l an dStat e Projec t o f th e Evaluatio no f Refiner y f Emissions' . ReportNe . 2 . Hire h1957 . j

:, e . . Steigefe^jferg^"JvVr^K^.-P9CJor£^UjLeafuL^'ia*-^ire^^Prros-aiHre:- " Relie f Valves v

.. . Joint;.0 1 s!tWst * F<itfm?y c ai ^ Sia ^ o f Refiner y

. Emissions . Report 'MJJTrVtiip'1957. 7 ' • ; * Steigerwald , B . J . Emission s o f Hydrocarbon s t o th e Atmospher e fro m Seal s o nPump s an

dCompressors . Join t District , Federa l an dStat e Projec t o f th e Evaluatio no f Refiner y Emissions . Repor t No . 6 . Apri l 1958 . 6 . Wetherold , R.G. , L.P . Provost , an dCD . Smith . (Radia nCorporation. ) Assessmen t o f Atmospheri c Emission s fro m Petroleu

m Refining , (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/2-80-075a-d . Apri l 1980 . 7 . U.S . Environmenta l Protectio nAgency . Fugitiv e Emissio nSource s o f Organi c Compound s - Additiona l Informatio no nEmissions , Emissio n Reductions , an

dCosts . Researc hTriangl e Park , N.C . Publicatio nNo . EPA-4S0/3-82-010 . Apri l 1982 . 8 . Mem o from

Hustvedt , K.C , EPA:CPB , t o Durham , J.F. , EPA-.CPB . Decembe r 2 , 1980 . 17 0 p . MR C SOCM I Fugitiv e Testing . 9 . U.S . Environmenta l Protectio nAgeney . Ai r Pollutio nEmissio nTes t a t Dow Chemica l Company . Researc hTriangl e Park , N . C EMB Repor t No . 78-0CM-12 C U.S . Environmenta l Protectio nAgency . Ai r Pollutio nEmissio nTes t a t Unio nCarbid e Corporation . Researc hTriangl e Park , N.C . EM B Repor t No . 78-0CM-12A . 5- 1

E_______ UJ____Z

_

U.S . Environmenta l Protectio nAgency . Ai r Pollutio nEmissio nTes t a t Stauffe r Chemica l Co . Researc hTriangl e Park , N.C . EM B Repor t No . 78-0CM-12D . U.S . Environmenta l Protectio nAgency . Ai r Pollutio nEmissio nTes t at Phillip s Petroleu

m Co . Researc hTriangl e Park , N.C . EM B Repor t No . 78-0CM-12E . . U.S . Environmenta l Protectio nAgency . Ai r Pollutio nEmissio nTes t at Refiner y E . Researc hTriangl e Park , N.C . EM B Repor t No . 78-OCM-12F . 10 . Meetin g Report . Honerkamp . R. , Radia nCorporation , t o Hustvedt , K.C , EPA:CPB , an

d distributio nlist . Jun e 12 , 1979 . 1 4 p . Minute s o f meetin g betwee nEPA

an d DuPon t representative s abou t fugitiv e emissio n sampling . 11 . Lette r an

d attachmen t fro

m Cox , J.B. , Exxo nChemica l Company , t o Weber , B. , EPA:CPB . Februar y 21 . 1978 . 4 p . Copy o f lette r abou t cyclohexan e uni t fugitiv e los s dat a sen t t o Hydroscience . Lette r an

d attachmen t fro

m Cox , J.B. , Exxo nChemica l Company , t o Walsh , R.T. , EPA:CPB . Marc h21 , 1979 . 4 p . Informatio nabou t cyclohexan e unit . 12 . Blacksmith , J . R. , e t al . (Radia nCorporation. ) Problem-Oriente d Report : Frequenc y

o f Lea k Occurrenc e fo r Fitting s i nSyntheti c Organi c Chemica l Plan t Proces s Units . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/2-81-003 . Septembe r 1980 . 13 . Langley , G . J . an d R . G . Wetherold . (Radia nCorporation. ) Evaluatio no f Maintenanc e fo r Fugitiv e VO C Emission s Control . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/52-81-080 . Ma y 1981 . 14 . Langley , G . J . e t al . (Radia nCorporation. ) Analysi s o f SOCM I VO C Fugitiv e Emission s Data . (Prepare d fo r U.S . Environmenta l Protectio n Agency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/2-81-111 . Jun e 1981 . 15 . Langley , G.J. , an d L.P . Provost . (Radia nCorporation. ) Revisio no f Emissio nFactor s fo r Nonmethan e Hydrocarbon s fro m Valve s an

dPum pSeal s • in.SOCM I Processes . Technica l Note . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N. C Novembe r 1981 . 16 . Schwanecke , R . "Ai r Pollutio nResultin g fro m Leakag e fro

m Chemica l Facilities. " Luftverun-reinigung . 1970 , pp. : 9-15 . Translate dfo r th e U.S . Environmenta l Protectio nAgenc y b y SCITRAN . Sant a Barbara , California .



### 5- 2<*.*% P.7 8

Kremer , H . "Leakage s fro m Stati c an

d Dynami c Seal s inChemica l an d Petrochemica l Plants. " 4t hMeetin g O GEW/DGMK . Salzburg . Octobe r 1976 . Translate d fo r th e U.S . Environmenta l Protectio nAgenc y b y SCITRAN , Sant a Barbara , California . Bierl , Alois , e t al . "Leakag e Rate s o f Sealin g Elements. " Chem . Ino . Tech . 4 9 (No . 2 ^ 1977 , pp . 89-85 . Translate dfo r th e U.S . Environmenta l Protectio nAgenc y

b y SCITRAN . Sant a Barbara , California . Schwanecke , R . "Ai r Pollutio nThroug hSmal l Leakage s fo r Equipn.e.i l th e Chemica l Industr y an d Way s fo r Thei r Prevention. " Translate d fo r U.S . Environmenta l Protectio nAgenc y b y SCITRAN . Sant a Barbara , California . 

### th e

17 .

18 .

19 .

20 .

2 1 Lee , Ku n- Chich , e t al . (UnionCarbid e Corporation . Sout hCharleston , Wes t Virginia. ) " A Fugitiv e Emissio nStudy ina Petrochemica l Manufacturin g Unit. " Presente d a t th e 73r dAnnua l Meetin g o f th e Ai r Pollutio nContro l Associatio ninMontreal , Quebec . Jun e 22-27 , 1980 . Harvey , Cynthi a M . an d A . Car l Nelson . (PEDC o Environmenta l Inc. ) Fugitiv e Emissio nDat a - HighDensit y Polyethylen e Proces s Uni t (Prepare d fo r U.S . Environmenta l Protectio nAgency. ) Researc hXri Park , N. C Publicatio nNo. • EPA.-600/2-81-1O9- . Jun e 

### VO C

DuBOM' i D.&.V:'t t l l Frequencie s fo r Fitting s i n Protectio nAgency. ) N.C . Jul y

1982 . O R. ) Eiefssi m Faetars- -:tM

r ants. . {?r%p&re<_ fo r U.S . Environasnta l Mo . SO-FOL-1 . Researc hTriangl e Park ,
Wiesenborn , D.P. , e t al . (Radia nCorporation. ) Lea k Frequenc y an d Emissio nFactor s fo r Fitting s inCok e Ove nBy-Produc t Plants . (Prepare d fo r U.S . Environmenta l Protectio nAgency. ) EM B Repor t No . 81-BYC-12 . Researc hTriangl e Park , N. C Januar y 1982 . Wetherold , R . G. , L . P . Provost , an dC . D . Smith . (Radia nCorporation. ) Assessmen t o f Atmospheri c Emission s fro m Petroleu

m Refining , Appendi xB : Detaile d Results . (Prepare d fo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . Publicatio nNo . EPA-600/2-80-075c . Apri l 1980 . 22 . Referenc e 3 . 23 . Eaton , W.S. , e t al . Fugitiv e Hydrocarbo nEmission s fro m Petroleu

m Productio nOperations . America nPetroleu m Institut e Publicatio n No . 4322 . 1980 . 24 . Harris , G . E . (Radia nCorporation. ) Emissio nTes t Report : Fugitiv e Tes t Repor t a t th e Gul f Venic e Ga s Plant , Volume I . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . EM B Repor t No . 81-0SP-8 . Jul y 1981 .



### 5- 3

m nP.7 9 

## «-fc :

Harris , G . E . (Radia nCorporation. ) Emissio nTes t Report : Fugitiv e VO C Testin g a t th e Texa s Paradi s Ga s Plant , Volume I . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc hTriangl e Park , N.C . EM B Repor t No . 80-0SP-7 . Jul y 1981 . 25 . U.S . Environmenta l Protectio nAgency . Compilatio no f Ai r Pollutan t Emissio nFactors . Researc hTriangl e Park , N.C . AP-42 . Februar y 1980 . 26 . Powell , D. , e t al . (PES , Inc. ) Developmen t o f Petroleu m Refiner y

Plo t Plans . (Prepare dfo r U.S . Environmenta l Protectio nAgency. ) Researc h Triangl e Park , N.C . Publicatio nNo . EPA-450/3-78-025 . Jun e 1978 . 27 . Williamson , H . J. , e t al . (Radia nCorporation. ) Mode l fo r Evaluatin g th e Effect s o f Lea k Detectio nan dRepai r Program s o

nFugitiv e Emissions . Technica l Not e DCN

81-290-403-06-05-03 . Septembe r 1981 .

5- 4

## 4 ' * P.8 0

TECHNICA L REPOR

T OAT A (Please read

Instructions on the reverse before completing) 1
. REPOR T NO
. EPA-450/3-86-00 2 3
. RECIPIENT S ACCESSIO N NO
.
4
. TITL E AN O SUBTITL E Emissio n Factor s fo r Equipmen t Leak s o f VO C an d HA P 8
. REPOR T OAT E Februar y10

. 198 6 6
. PERFORMIN G ORGANIZATIO N COO E

7
. AUTHOR(S ) Joh n H
. E
. Stellin g II I 8
. PERFORMIN G ORGANIZATIO N REPOR T NO
. 

### DC N 86-203-024-63-0 6
9
. PERFORMIN G ORGANIZATIO N NAM E AN O ADDRES S Radia n Corporatio n 320 0 E
. Chape l Hil l Road/Nelso n Highwa y Researc h Triangle Park , N.C
. 2770 9 10 . PROGRAM ELEMEN T NO .
11 . CONTRACT/GRAN T NO . 68-02-3889 , W

A 6 3
12
. SPONSORIN G AGENC Y NAM E AN O AOORES S U.S
. Environmenta l Protectio n Agenc y Offic e o f Ai r Qualit yPlannin g an d Standard s Emissio n Standard s an d Engineerin g Divisio n Researc h Triangl e Park , N.C
. 2771 1 13
. TYP E O F REPOR T AN D PERIO D COVERE D
14
. SPONSORIN G AGENC Y COO E

15
. SUPPLEMENTAR Y NOTE S Projec t Office r i s Rober t E
. Rosensteel , Mai l Drop
. 13 , (919 ) 541-5605
. 16 . ABSTRAC T

.. 9 Th e repor t summarize s th e developmen t o f emissio nfactor s fo r volatil e orgpsf c compound (VOC ) equipmen t leaks - The.-backgroun d informatio nusedi nemiss i-PJtJ*G&fe'- - developmen t i s reviewed . The . estimatio ntechnique s fo r generatio no f VO t emi s s i dinfactor s ar e describe d an d illustrate d wit ha

n example . Th e applicatio no f th e estimatio ntechnique s i s demonstrate dfo r bot hVO C an d hazardou s ai r pollutant s (HAPs)
.

17
. KE Y WORD S AN D DOCUMEN T ANALYSI S DESCRIPTOR S b.lOENTlFIERS/OPE N ENOE D TERM S c . COSAT i Field/Group Fugitiv e Emission s Volatil e Organi c Compound s Hazardou s Ai r Pollutant s

18
. DISTRIBUTIO N STATEMEN T Releas e t o Publi c 19
. SECURIT Y CLAS S (This Report) Unclassifie d 21
. NO
. O F PAGE S 7 0 20
. SECURIT Y CLAS S (This page I Unclassifie d 22
. PRIC E

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