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# OAR Box 1856 Prepped byKeeiaRichards



### Document

Number: 

# 76 ) ll-A-1 3 Docket Number: 

# A-87-1 1

Printed 11/24/2008 12:41:51 PM Sheet 76 of 82EPA-AA-SDSB-87-0 7 E2_ 

## 2L-A-/ 3

Technica l Repor t

Investigatio no f th e Nee d fo r In-Us e Dispensin g Rat e Limit s an

d Fue l Nozzl e GeometryStandardizatio n

May198 7

NOTIC E Technica l Report s d o no t necessaril yrepresen t fina l EP A decision s o r positions . The yar e intende d t o presen t technica l analysi s o f issue s usin g dat a whic har e currentl yavailable . Th e purpos e i nth e releas e o f suc h report s i s t o facilitat e th e exchang e o f technica l informatio n an

d t o infor

m th e publi c o f technica l development s whic hma yfor mth e basi s fo r a fina l EP A decision , positio no r regulatoryaction .

Standard s Developmen t an d Suppor t Branc h Emissio nContro l TechnologyDivisio n Offic e o f Mobil e Source s Offic e o f Ai r an

d Radiatio n U . S . Environmenta l Protectio nAgenc yP. 3 Tabl e o f Content s Sectio nPag e I . Introductio n3 II . Definitio no f Term s 3 III . Discussio no f th e Issue s 5 A . In-Us e Dispensin g Rate s 6 B . Nozzl e Geometrie s 8 IV . CA AAuthorit ym1 2 V . Benefit s 1 3 VI . Implementatio n 1 4 VII . Economi c Analysi s 1 7 VIII . Summaryan

d Conclusion s 1 9P. 4 

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- I . Introductio n A s a par t o f th e technica l informatio nreceive d during th e developmen t o f EPA' s draf t refueling emission s tes t procedure , on e aut o manufacture r suggeste d tha t th e in-us e dispensing rat e o f gasolin e woul d hav e t o b e controlle d an d gasolin e nozzl e geometrie s standardize d i norde r t o assur e th e prope r in-us e operatio n o f onboar d vapo r recoverysystem s . (onboar d systems).[1 ] I nrespons e t o thi s suggestion , th e effect s tha t thes e tw o parameter s (dispensing rat e an d nozzl e geometry ) ma y hav e o nrefueling emission s contro l wer e studied . A s i s discusse d below , thi s stud yled t o th e conclusio ntha t a dispensing rat e limi t o f 1 0 gallon s pe r minut e (gpm ) woul d b e complementaryt o th e operatio no f anonboar d systeman d th e contro l o f spillage-relate d refueling emission s sinc e th e maximu min-us e dispensing rat e an d th e dispensin g rat e fo r vehicl e refueling emissio ncertificatio n testin g woul d b e th e same . However , wit hregard t o th e second parameter , additiona l informatio nan

d publi c commen t i s neede d o nth e effect s o f nozzl e geometrie s o n refueling emission s contro l befor e i t ca n b e conclude d tha t actio ni s needed . A s a resul t o f th e conclusion s fromthi s study , th e Agenc y pursue d th e developmen t o f a voluntaryin-us e dispensin g rat e standar d wit hth e America nPetroleu mInstitut e (API) , whiqh represent s petroleu m industryinterests . A s summarize d i n thei r statemen t o f Augus t 6 , 1986 , [2 ] AP I conclude d tha t i t i s no t feasibl e t o develo p a voluntarystandard . AP I als o conclude d tha t i t shoul d b e th e moto r vehicl e manufacturers ' responsibilit yt o develo p refueling contro l system s whic hcaus e nozzl e shut-of f withou t spitbac k i f desig nflo wlimit s ar e exceeded . Thi s repor t present s th e result s o f th e investigatio no f th e effect s o f dispensin g rate s an d fue l nozzl e geometrie s o n refueling emission s an d support s EPA' s proposa l t o regulat e in-us e dispensin g rate s an d furthe r stud

yth e nee d fo r som e for mo f nozzl e standardization . Th e firs t portio n o f th e repor t i s devote d t o background . Afte r definin g a fe wke y terms , th e repor t begin s wit ha discussio no f th e issues . Thi s i s followe d bya presentatio no f EPA' s statutoryauthorit yt o regulat e fue l dispensin g rates . Afte r thi s background informatio n i s presented , th e benefits , implementatio n approach , an

d economi c impac t o f a dispensin g rat e limi t ar e discussed . Th e repor t close s wit ha brie f summaryan d conclusions . II . Definitio no f Term s Define d belo war e some ke yterm s relate d t o fue l dispensing , fue l dispensin g units , an d relate d hardware . Item s relate d t o th e fue l nozzl e itsel f ar e identifie d i nFigur e l .P. 5



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-

FicTure 1

Nozzl e Body A.rt-rmatic Fue l PvnpNozzl e [^—.Lengt ho f Spout— ^

Spout' s |< - Straigh t • Sectio n

_. . Autonati c Shutof f 

### ***** . Por t T Angl e

HandLeve r

Automati c Cli pP. 6 

### -5

- "Spills " - los s o f gasolin e during th e refueling even t du e t o on e o r mor e o f four causes : pre-fil l drip , spitback , overflow , an

d post-fil l drip.[3 ] "Spitback " - discharg e o f gasolin e fromth e fillpip e resulting from

pressur e build-up i nth e vapo r spac e durin g anautomati c fill.[3 ] "Overflow " - los s o f fue l fromth e fillpip e whe nth e amoun t o f gasolin e dispense d exceed s th e tank capacity ; ofte ncause d b

ytopping off.[3 ] "Dispensing unit " - th e entir e refueling hardwar e tha t exist s abov e ground . "Pump " - th e refueling hardwar e tha t exist s beneat hth e ground o r withi nth e dispense r whic hdrive s th e dispensing unit . "Nozzle " - th e hand-hel d portio no f th e dispensing uni t whic hconsist s o f th e nozzl e body , stem , an d spout . "Spout " - th e termina l en d o f th e fue l nozzl e whic hfit s int o th e vehicle' s fillpip e whe nrefueling . i "Automati c Shut-of f Port " - th e hol e nea r th e ti p o f th e spou t whic hactivate s th e nozzl e automati c shut-of f whe n covere d wit hliquid . Wit hthes e basi c termdefinitions , i t i s no wpossibl e t o discus s th e issue s involve d i nthi s study . III . Discussio no f th e Issue s Alimite d amoun t o f informatio navailabl e i n th e literatur e suggest s tha t bot hth e fue l dispensin g rat e an d nozzl e geometryca naffec t th e amoun t o f emission s generate d i n a refuelin g event . Thi s relationshi p exist s becaus e bot hth e dispensin g rat e an d nozzl e geometryca naffec t th e amoun t o f turbulen t mixin g whic hoccur s i nth e fillpipe , an d experienc e show s tha t refueling emission s varydirectl ywit hth e amoun t o f turbulen t mixing.[4 ] Thu s thes e parameter s mayhav e a smal l effec t o nbot hth e uncontrolle d refueling emissio nrat e an d th e refueling emission s load t o th e caniste r i nanonboar d vapo r recoverysystem . Further , i na relate d area , on e sourc e suggest s tha t gasolin e spill s during " refueling ar e als o directl yaffecte d b yth e nozzl e configuratio n an d dispensin g rate.[3 ] Th e effec t o f dispensing rate s an d nozzl e geometrie s o n th e contro l o f refueling emission s an d gasolin e spillag e i s discusse d below , togethe r wit hth e rational e fo r an ypotentia l regulatorycontrols . Dispensin g rate s ar e considere d firs t an d nozzl e geometrie s follows .P. 7 

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- A . In-us e Dispensin g Rate s Th e fue l dispensin g rat e i s importan t becaus e o f it s effec t o nth e desig nan d performanc e o f anonboar d vapo r recoverysystem . A s mentione d above , th e fue l dispensin g rat e slightl yaffect s th e refueling emissio nrat e whic hi s on e o f th e factor s impacting caniste r size . I naddition , sinc e th e fue l dispensin g rat e determine s th e rat e a t whic hfue l vapo r i s displace d fromth e tank durin g a refueling event , i t als o impact s th e desig no f a nonboar d system . Th e majo r effect s ar e o nth e vapo r lin e diamete r neede d t o optimiz e syste m backpressur e characteristics , an d th e siz e and shap e o f th e caniste r neede d t o captur e th e refueling emissions'. " Th e dispensin g rat e als o ha s some effec t o nth e potentia l fo r gasolin e spillag e (spitback ) during a refueling event . I f th e fue l i s dispense d a t a rat e greate r tha n vapor s ca nb e displace d fromth e system , backpressur e withi nth e systemca n increas e an

d caus e a prematur e shut-of f o f th e fue l nozzl e an d th e possibilit yo f a fue l spitback . Sinc e th e fue l dispensin g rat e i s on e o f th e ke yfactor s affectin g th e desig no f anonboar d system , EP Aha d t o establis h a dispensin g rat e valu e fo r us e i nrefueling emission s testing . Rathe r tha narbitraril ychoosing a value , i t wa* s importan t tha t th e value s specifie d i nth e certificatio n tes t procedur e b e representativ e o f th e dispensing rate s expecte d in-use . Aninvestigatio no f th e curren t in-us e dispensin g rate s by AP I reveale d tha t value s generall yrang e from6-1 2 gpm , wit h value s normall ylying betwee n8-1 0 gpm . Th e in-us e dispensin g rate s o f gasolin e varie s dependin g o na numbe r o f differen t factors . Olde r an d smalle r servic e station s us e a suctio npum p whic hi s locate d insid e th e individua l dispenser . Thes e suctio npum

p dispenser s normall yoperat e a t 8 t o 9 gpm.[5 ] Newer , highe r volum e facilitie s us e submersibl e turbin e pump s whic har e locate d awayfromth e dispenser s an d ar e eithe r o no r i nth e underground storag e tank . The yserv e al l th e dispensers , an d nozzle s drawin g produc t fromth e tank , thu s th e actua l flo w rat e varie s dependin g o nth e numbe r o f nozzle s bein g operate d fromon e pump . Thes e submersibl e pump s ar e o f a highe r horsepower , an

d delive r gasolin e a t rate s o f 1 0 t o 1 2 gp m (presumabl ywhe nonl yon e o r tw o nozzle s ar e i noperation ) wit h a fe wnewe r facilitie s capabl e o f operatin g a t level s a s hig h a s 1 5 gpmunde r th e same conditions.[2,5 ] On e in-us e surve y reporte d ful l serv e dispensin g rate s o f 6. 5 t o 8 gpmwit hsel f servic e rate s slightl yhighe r a t 9 t o l l gpm.[5 ] Thes e rate s wer e observe d a t variou s dispenser s an d fromnozzle s o f differen t manufacturers . Al l o f th e availabl e informatio n indicate s tha t mos t in-us e dispensin g rate s fal l i nth e rang e o f 8 t o 1 0 gpmwit hevidenc e o f a trend towar d highe r rate s i n ne wstation s usin g highe r horsepowe r pumps .PS 

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- Base d o n thi s information , th e maximu mdispensing rat e i n EPA' s draf t refueling emission s tes t procedur e wa s se t a t 1 0 gpmt o correspond t o value s nea r th e highe r en d o f th e curren t in-us e dispensin g rat e range.[6 ] Th e automobile s bein g certifie d wil l the nb e designe d fo r an d teste d a t condition s mos t comparabl e t o thos e presente d in-use . EPA' s draf t refueling tes t procedur e woul d als o essentiall yrequir e tha t n o fue l spillag e occu r durin g th e refueling test , sinc e an y spille d fue l whic hevaporate s during th e tes t i s include d i n th e overal l emissio n results . Thus , th e implementatio n o f onboar d control s coul d als o resul t i na reductio ni nfue l spillag e (spitback ) whic hno woccur s whe n- th e fue l nozzl e automati c shut-of f i s activated . However , i f th e in-us e dispensing rate s increas e a s AP I predicts , th e dispensin g rat e use d fo r certificatio n testing o f onboar d vehicle s wil l n o longe r b e comparabl e t o thos e in-use.[2 ] Vehicle s equippe d wit honboar d system s wil l no t b e refuele d in-us e a t th e dispensin g rate s the ywer e designe d fo r i ncertification . Furthermore , manyvehicle s wil l no t b e designe d t o accep t suc hhighrefueling rate s an d prematur e shut-off s an

d fue l spillag e relate d t o spitback s mayincrease . Consequently , th e expecte d reduction s i nemission s du e t o spitbac k spillag e coul d b e decrease d o r los t totally , an d som e o f th e benefit s o f controlling refueling emission s ma yti e offse t i f spillag e increases . Ther e ar e basicall ytw o option s availabl e t o preven t a n incompatibilit ybetwee nth e certificatio n an d in-us e dispensin g rates . Th e firs t optio ni s t o se t th e dispensin g rat e use d fo r certificatio n testin g equa l t o th e maximu m rat e reasonabl y expecte d in-us e i nth e future , rathe r tha n 1 0 gpm . Thi s woul d ensur e tha t th e in-us e dispensin g rate s d o no t excee d th e rat e use d fo r certification , bu t i t coul d increas e th e cos t o f onboar d system s becaus e the ywoul d hav e t o b e designe d t o handl e muc hhighe r flo wrates . Thi s optio nals o allow s in-us e dispensin g rate s t o increas e eve nfurthe r i nth e futur e sinc e th e vehicle s woul d b e abl e t o accep t thes e highe r rates . Thu s incompatibilit ybetwee ncertificatio n an d in-us e dispensin g rate s coul d reappea r i nth e future , an d th e proble mwoul d no t b e solved . Th e second optio ni s t o implemen t a n in-us e dispensin g rat e limi t whic hi s equa l t o th e maximu m rat e use d i nth e certificatio n testin g o f onboard-equippe d vehicles . A s discusse d above , thi s valu e woul d b e -1 0 gpm . Unde r thi s option , retai l gasolin e marketer s an d wholesal e purchaser-consumer s woul d b e require d t o limi t th e dispensin g rat e o f thei r gasoline s t o 1 0 gpm . Th e maximu mdispensin g rat e chose nfo r certificatio n testin g (1 0 gpm ) i s base d o nvalue s found nea r th e hig hen d o f th e curren t in-us e range , s o mos t servic e station s woul d no t b e affecte d excep t t o restric t an yP. 9 

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- futur e changes . Thi s optio nwoul d ensur e tha t th e certificatio n an

d in-us e dispensin g rate s remai ncomparabl e i n th e future . Thi s compatibilit ywoul d enhanc e th e overal l effectivenes s o f th e onboar d refueling control s an d achiev e additiona l contro l o f refueling emission s byreducing th e amoun t o f in-us e spillage . Base d o n th e discussio nabove , th e second optio ni s mor e favorabl e i nassuring tha t th e maximu mcertificatio n an d in-us e dispensin g rate s remai nequivalent . Establishin g anin-us e dispensin g rat e limi t equa l t o th e maximu mcertificatio n rat e (1 0 gpm ) woul d guarante e tha t th e rat e used ^ i nth e desig no f th e onboar d systemfo r certificatio n testing ' is-comparabl e t o tha t in-use . Thi s woul d complemen t th e performanc e o f onboar d control s an

d reduc e in-us e spitbac k spillage . I naddition , an in-us e dispensin g rat e limi t wil l preven t increasing dispensin g rate s a s vehicle s tha t ar e designe d t o handl e highe r flowrate s ente r th e fleet , a s mayhav e occurre d unde r th e firs t optio n considered . A s wil l b e discusse d furthe r below , thi s optio n coul d als o provid e additiona l environmenta l benefit s by decreasin g th e amoun t o f gasolin e spillag e whic hoccur s durin g th e refueling o f vehicle s withou t onboar d controls . B . Nozzl e Geometrie s I A s wa s mentione d previousl yi nth e introduction , a t leas t on e automobil e manufacture r ha s expresse d concer nt o EP Atha t withou t uniformnozzl e geometrie s mechanica l fillpip e seal s ma y no t b e feasible . The yfee l suc hdesig nstandard s shoul d includ e a t minimu

m anin-us e dispensin g rat e limit , a s wel l a s specification s o nlength , diameter , positio nan d angl e o f nozzl e bends , positio no f latching mechanism s an d contro l o n burr s an

d protrusion s tha t coul d potentiall ydamag e th e sea l mechanis man

d harmth e onboar d contro l ef f iciency . [ 1 ] . . I na broade r context , th e SAE Fue l Suppl ySystem s Subcommitte e ha s als o expresse d simila r concern s regarding standar d nozzl e spou t specifications . A t a recen t meetin g o f thi s Subcommittee , severa l aut o manufacturer s conveye d a belie f tha t suc hnozzl e standard s ar e neede d t o ensur e prope r interfac e betwee nth e nozzl e spou t an

d aut o fillpipe.[7 ] I nrespons e t o thes e concerns , EPAinvestigate d th e effect s o f fue l nozzl e geometries . Durin g thi s investigation , i t wa s learne d tha t nozzl e geometrie s ma yhav e a neffec t o n spillage . First , according t o a stud ybyScot t Researc h Laboratories , th e nozzl e bendin g angl e ari d spou t lengt har e tw o factor s affecting spitbac k spillage.[3 ] Thes e ca ncaus e increase d splashing agains t th e fillpip e wal l an d greate r turbulence.[4 ] Thi s splashing an d turbulenc e coul d caus e mor e frequen t prematur e nozzl e shut-offs . Th e greate r numbe r o f prematur e nozzl e shut-off s result s i na nincreas e i nth e amoun t o f spitbac k spillag e whic hoccur s durin g refuelin g operations .P.1 0 

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- Second , th e bending angl e o f th e spou t affect s th e fue l flowt o th e vehicl e tank withi nth e fillpipe . Th e increase d splashing agains t th e fillpip e wall s an d greate r turbulenc e create d bysome bendin g angle s preven t optimu mfue l flow.[4 ] Du e t o thi s varianc e i nangles , some fillpipe s ma yno t b e abl e t o achiev e thei r designfil l rat e withou t prematur e shut-offs . Therefore , standardize d nozzl e geometrie s coul d eas e th e automobil e manufacturers ' desig no f fillpipe s whic hensur e optimu mfue l flo wt o th e vehicl e tank an d minimiz e prematur e shut-offs . Third , sinc e nozzl e geometrie s als o affec t th e locatio no f th e automati c shut-of f por t withi nth e fillpipe , varyin g nozzl e an d fillpip e design s ca nimpac t th e potentia l fo r fue l spitbac k whe nth e automati c shut-of f devic e i s activate d a t th e en d o f a refill . Th e close r th e shut-of f por t i s t o th e fillpip e outlet , th e highe r th e fue l mus t ris e i nth e fillpip e t o activat e th e shut-off , an d thu s th e greate r th e chanc e fo r a fue l spitbac k t o occur . I naddition , thi s investigatio nstudie d th e currentl y availabl e fue l nozzles . A s i s discusse d i nmor e detai l below , curren t nozzl e configuration s an d geometrie s wer e investigate d an d found t o b e relativel ysimilar . Thi s similarit yi n configuration s i s sough t primaril yfo r marketin g reason^ . Underwriter s Laboratorie s examine s th e compatibilit yo f differen t manufacturers ' nozzle s wit hliste d power-operate d dispensing unit s an d label s th e nozzle s a s "interchangeable " i f compatible.[8 ] Al l "interchangeable " nozzle s ca nb e use d o n an yliste d dispensing unit . Therefore , i norde r t o b e "interchangeable " an d mor e marketable , th e desig no f th e spou t an d handl e locatio no f mos t nozzle s ar e comparable , bu t no t necessaril yidentical . Furthermore , EPAregulatio nan d some voluntar ystandard s fo r nozzl e design s als o contribut e t o th e similarit yo f curren t nozzl e geometries . Thes e regulation s an d standard s includ e th e following : < » Federa l Registe r - 4 0 CF R80.2 2 Thi s ruling regulate s th e outsid e diamete r fo r bot h leade d an

d unleade d nozzle s spouts . I t als o specifie s a minimu mstraigh t sectio n lengt han d positio no f th e retaining spring fo r unleade d nozzl e spouts.[9 ] U L 84 2 - "Valve s fo r Flammabl e Fluids " Thi s standar d o f Underwriter s Laboratorie s specifie s th e strengt han

d enduranc e o f th e nozzl e material . I t als o give s a maximu mnozzl e length.[10 ]P.1 1

•• • ' . -10

-

* NFP ANo . 3 0 - "Flammabl e an d Combustibl e Liquids " Thi s standar d o f th e Nationa l Fir e Protectio n Associatio nspecifie s tha t an ynozzl e dispensin g Clas s I liquid s suc ha s gasolin e mus t b e automati c closing an

d liste d byUnderwriter s Laboratorie s (an d therefor e conform

t o U L 842).[11 ] Complianc e wit hth e EPAregulatio nruling i s mandatoryfo r al l nozzl e manufacturers , wherea s mos t manufacturer s choos e t o adop t th e othe r voluntarystandard s presente d abov e solel yfo r insurance/liabilit ypurposes . I t i s importan t t o emphasize , however , tha t t o dat e n o rea l limit s o nth e flo wrate s o r configuration , beside s diameter s an d a straigh t sectio nlength , hav e bee nmade . Th e manufacturer s hav e tota l freedom i nthei r nozzl e designs , excep t fo r marke t an d insuranc e constraints . Th e Internationa l Standard s Organizatio n (ISO ) i s currentl yevaluating possibl e desig nstandard s fo r al l fue l nozzle s i n orde r t o reduc e fir e risks . Thes e draf t standard s includ e specification s o nth e dimension s "an d geometrie s fo r nozzl e spout s a s wel l a s a maximu mdispensin g rate.[12 ] Respons e t o thes e propose d IS O standard s b ySAE and othe r America nconcern s ha s no t bee npositive . The ybeliev e tha t thes e standard s specif yto o manyparameter s an d ar e therefor e to o restrictive . Consequently , th e U.S . vote d t o disapprov e th e propose d IS O standards.[13 ] A s par t o f thi s investigatio no f fue l nozzl e geometries , some ke ydimension s o f nozzl e spout s from th e tw o larges t nozzl e manufacturer s wer e compared.[14,15 ] Th e design s o f thes e tw o nozzle s ar e followe d closel yb yothe r manufacturer s an d thes e nozzle s ar e ofte nrebuilt . Thu s the yar e quit e representativ e o f th e majorit yo f in-us e nozzles . Thes e fue l nozzl e desig ncharacteristic s o f th e tw o manufacturer s ar e presente d i nTabl e 1 . Thi s tabl e show s tha t i ngenera l th e tw o nozzl e spout s ar e simila r wit hsligh t difference s i nth e straigh t sectio n lengt han d dispensin g rat e characteristics . Sinc e th e nozzl e configuration s ar e quit e similar , nozzl e standardizatio nma yno t b e necessary . I t i s no t clea r that , mino r difference s suc ha s thes e woul d impac t th e operatio no f anonboar d system , althoughther e i s some evidenc e tha t nozzl e geometrie s coul d veryslightl yaffec t th e refueling emissio n rat e du e t o varyin g amount s o f turbulen t mixin g an d drople t entrainment . However , eve n i f nozzl e geometrie s ar e standardized , i t i s no t clea r tha nth e desire d effec t woul d b e achieved . Th e nozzl e spou t positio nwithi nth e fillpip e i s als o affecte d by th e angl e a t whic hth e individua l refuele r insert s th e nozzl e itsel f durin g eac hrefueling event . Th e variabilit yi nnozzl e positio ncause d bythi s effec t alon e coul d b e enought o negat e an ypotentia l emissio no r contro l system operatio nbenefit s whic haris e from

nozzl e standardization .-11

- Tabl e Fue l Nozzl e De s Dimensio n Tota l Spou t Lengt h Spou t Straigh t Sec . Lengt h Spou t Bending Angl e Automati c Shut-of f Location * Nozzl e Outsid e Diamete r Dispensing Rat e @ 5 ps i A P @ 1 0 ps i A

P

* Distanc e from

nozzl e tip . * * Maximum . 

### ig n 

### 1 Characteristic s OP W11- A 

### 7 " 3.9 " 24-25 ° 0.73 " .81 " 4 gpm 1 0 gpm EMC O

, Wheato nA200 0

7.25 " 2.9 " 

### 27 ° 0.67 " .81 " 7.5gp m 13.5gp m



### 1 P.1 2P.1 3
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- Give n thi s effec t an d th e relativ e uncertaint yregarding th e impac t o f nozzl e geometrie s o nrefueling emission s an d thei r control , i t i s no t clea r tha t nozzl e geometrie s nee d t o b e standardize d t o contro l refueling emissions . I f furthe r informatio nbecome s availabl e whic hdemonstrate s tha t th e impact s o f varyin g nozzl e geometrie s o nrefueling emission s an d effect s o n onboar d contro l design s ar e significan t an d tha t th e cost s o f nozzl e standardizatio nar e reasonable , the n suc h standardizatio n wil l b e considered . Base d o nth e rational e presente d above , i t appear s tha t in-us e dispensin g rat e limit s woul d enhanc e .th e effectivenes s o f onboar d control s an d reduc e spitbac k spillage . "Standardize d nozzl e design s ma yb e considere d i nth e future , bu t furthe r stud yan d informatio ni s required . Th e remainde r o f thi s repor t provide s furthe r background informatio nan d analysi s pertaining t o a dispensing rat e limi t requirement . IV . CA AAuthorit y Th e Clea n Ai r Ac t (CAA ) give s EP Aauthorit yt o regulat e th e in-us e dispensin g rate . EPA' s authorit yi nthi s are a stem s fromSectio n21 1 (c ) o f th e Act . Thi s sectio nallow s EP At o contro l o r prohibi t th e introductio nint o commerc e o r offerin g fo r sal e o f an

yfue l fo r us e i na moto r vehicl e o r motd r vehicl e engin e i f th e emissio nproduct s o f th e fue l contribut e t o ai r pollutio nwhic hendanger s publi c healt ho r welfar e o r th e emissio nproduct s o f suc hfue l wil l impai r t o a significan t degre e th e performanc e o f an yemissio ncontro l system . I n thi s case , th e emissio nproduct s o f th e fue l ar e th e refuelin g vapor s an

d evaporate d spille d fue l associate d wit hth e dispensing o f gasoline . Thes e vapor s ar e photochemicall y reactiv e hydrocarbon s whic hcontribut e t o th e formatio no f ozone , anNAAQ S criteri a pollutant . Th e emissio n contro l systemo f interes t i nthi s cas e i s anonboar d vapo r recovery system . A s discusse d previously , dispensin g rat e limit s coul d enhanc e th e efficien t performanc e o f anonboar d systeman d avoi d significan t impairmen t i nth e contro l o f refuelin g emission s byonboar d control s througha reductio ni nspillage . Sectio n21 1 (c)(2)(B ) furthe r require s EPAt o conside r al l availabl e scientifi c an d economi c dat a o n possibl e alternatives , including a cos t benefi t analysi s comparin g emissio ncontro l systems , whe nregulating a fue l i norde r t o protec t th e effectivenes s o f emissio ncontrols . Th e alternativ e t o onboar d refueling control s i s Stag e I I vapo r recoverysystems . Thi s alternativ e ha s bee nthoroughl y analyze d byEPA . Althoug hStag e I I i s a technicall yfeasibl e alternative , EP Abelieve s tha t vehicle-base d vapo r recovery , o r onboar d systems , i s th e preferre d contro l approach . Regardless , Stag e I I system s woul d mos t likel yals o requir eP.1 4 -13

- flo wrat e limit s t o ensur e prope r performanc e a s i s no w require d i nCalifornia.[16 ] Thus , a limi t o nin-us e dispensin g rate s appea r consisten t wit hth e requirement s o f Sectio n211(c ) o f th e CAA . V . Benefit s Anumbe r o f benefit s canb e achieve d bylimiting in-us e dispensing rates . Thes e includ e enhance d contro l o f refuelin g emissions , gasolin e savings , plu s healt han d safet ybenefits . Eac ho f thes e i s discusse d below . First , a s previousl ymentioned , a dispensin g rat e requiremen t woul d complemen t th e efficien t operatio no f a n onboar d refueling contro l system . Wit ha dispensin g rat e limit , th e dispensing rat e use d fo r th e desig no f anonboar d systemwoul d b e compatibl e wit hth e rate s observe d in-use . Second , a dispensin g rat e limi t woul d provid e bot h refueling emissio nreduction s an d gasolin e saving s byreducing in-us e spillage . Adispensin g rat e limi t woul d reduc e o r practicall yeliminat e prematur e nozzl e shut-off s an d spitbac k fromonboard-equippe d vehicle s an d reduc e th e spitbac k from curren t in-us e vehicle s withou t onboar d controls . Th e onboar d vehicle s woul d b e designe d t o accommodat e 1 0 gpmdispensiri g rate s withou t spitback . Fo r in-us e vehicle s withou t onboar d controls , a dispensing rat e limi t woul d reduc e spillag e fo r thos e vehicle s whic hca nhandl e a flo wrat e o f 1 0 gpm , bu t no t highe r value s whic hcoul d occu r i f in-us e dispensin g rate s wer e allowe d t o increase . However , some in-us e vehicle s canno t handl e eve n a 1 0 gpmdispensin g rate ; a dispensin g rat e limi t woul d no t hav e an

yeffec t o nth e spitbac k from thes e vehicles . Th e curren t averag e emissio nfacto r associate d wit h spitbac k spillag e i s 0.1 5 g/gallo n o f dispense d fuel.[3 ] Usin g thi s emissio n facto r an d EPA' s fue l consumptio nprojectio nfo r 1995 , spitbac k spillag e i s estimate d t o caus e abou t 11,00 0 ton s o f refueling emission s i ntha t year.[17 ] Thi s spitbac k spillag e amount s t o 3. 7 millio ngallon s o f gasolin e spille d i n 1995 . I n1995 , th e vehicle s withou t onboar d control s wil l compris e abou t 5 0 percen t o f th e tota l vehicl e fleet , i f onboar d control s ar e implemente d fo r 199 0 mode l yea r vehicles.[18 ] Assumin g tha t a dispensin g rat e limi t woul d eliminat e spitbac k from al l vehicle s wit honboar d system s and one-hal f o f non-onboar d equippe d vehicles / an d a gasolin e pric e o f $ 1 pe r gallon , suc ha dispensing rat e -limi t coul d provid e a saving s o f approximatel y$2. 8 millio nfo r gasolin e consumer s i n 1995 . Thi s provide s anemissio nreductio n o f 8,25 0 ton s pe r year . I nadditio nt o thes e emissio nreduction s an d gasolin e savings , a dispensin g rat e limi t woul d provid e additiona l convenienc e t o th e genera l publi c byreducin g spillag e o f gasolin e o nautomobile s o r persons .P.1 5 -14

- I t i s importan t t o not e tha t th e curren t spitbac k spillag e emissio nfacto r o f 0.1 5 g/gallo n o f dispense d fue l i s probabl y conservative . Thi s emissio nfacto r originate d froma 197 2 stud ydon e byScot t Researc hLaboratories . Sinc e mos t station s i n197 2 use d suctio npum p dispensers , whic hhav e lowe r dispensing rate s tha nth e curren t station s usin g submersibl e turbin e pumps , i t woul d b e reasonabl e t o assume tha t th e in-us e dispensing rate s a t tha t time wer e lowe r tha npresen t rates.[2 ] Sinc e th e stud yfoun d a highe r probabilit yfo r spitbac k spillag e a t faste r dispensing rates , today' s spillag e emissio nfacto r mayb e greater . Furthermore , a t th e tim e o f th e study , mos t station s wer e ful l servic e jan d onl ygasolin e attendants , peopl e wit hgreate r experienc e dispensin g gasolin e tha ntoday' s self-servic e customers , wer e use d i n thi s analysis . Hence , i t i s reasonabl e t o believ e tha t today' s self-serv e customer s mayspil l gasolin e mor e frequentl yan d i n large r amount s tha nth e gasolin e attendant s use d i nth e 197 2 study . Anothe r importan t facto r i nthi s Scot t stud yi s th e presenc e o f a perso nmonitoring th e gasolin e attendants . Wit h a monito r present , th e attendant s coul d hav e bee nmor e carefu l an d les s likel yt o spil l gasoline . Fo r thes e reasons , th e 0.1 5 g/gallo nemissio nfacto r use d i nthi s repor t fo r spitbac k spillag e ma yb e conservative . Third,

- establishing a nin-us e dispensin g rat e limi t wil l provid e some healt hbenefit s fo r th e genera l public . A dispensin g rat e limi t wil l hel p reduc e th e ozon e concentratio n i nth e lowe r atmospher e b yenhancing contro l o f refuelin g emissions . I n addition , repeate d o r prolonge d derma l contac t wit hliqui d gasolin e du e t o spillag e ca ncaus e irritatio nan d dermatiti s fo r some individuals.[19 ] Thus , ther e ar e some healt hbenefit s gaine d fromlimiting th e in-us e dispensin g rates . I nadditio nt o th e healt hbenefits , a dispensin g rat e limi t provide s some additiona l safet ybenefit s fo r refuelin g operations . Th e refueling operatio nwoul d b e inherentl ymor e saf e becaus e o f reductio ni nspitbac k an d spillage . Anin-us e dispensin g rat e limi t woul d hel p t o reduc e spillag e durin g refueling , an

d woul d thu s contribut e t o a reductio ni nth e potentia l fo r fire s cause d b yinadverten t ignitio no f spille d gasoline . VI . Implementatio n Anyregulatio n t o contro l dispensin g rate s shoul d b e implemente d wit hminima l impac t o nservic e statio noperations . Wit hthi s i nmind , th e possibl e approache s fo r limiting in-us e dispensin g rate s wer e evaluated . Th e implementatio n approache s ar e discusse d belo wincluding th e necessaryliabilit yan d enforcemen t aspects . However , on e o f th e ke yfactor s affectin g ho wdispensin g rat e limit s coul d b e regulate d i s th e natur e an d structur e o f th e nozzl e industry . Thi s i s discusse d first .P.1 6 -15

- Sinc e anin-us e dispensing rat e limi t and/o r nozzl e geometrystandard s woul d hav e some impac t o nth e nozzl e industry , i t i s importan t t o highligh t it s structure . Th e fue l nozzl e industryconsist s o f bot hprimarymanufacturer s an d rebuilders . Th e primar ynozzl e manufacturer s produc e equipmen t fromal l ne wmaterial s wherea s rebuilder s reus e th e origina l nozzl e bod

ycasting s an

d replac e al l th e ol d an d wor noperatin g parts . Accordin g t o th e Petroleu mEquipmen t Institute , approximatel y7 0 percen t o f th e entir e marke t consist s o f originall ymanufacture d nozzles.[20 ] Moreover , th e nozzl e marke t structur e consist s primaril yo f a fewlarg e origina l manufacturers , a fewmid-siz e origina l manufacturer s wh o als o rebuil d nozzles , an d severa l smal l rebuilders . " ' Th e rebuilders , o r remanufacturers , rang e greatl yi n size.[20 ] Som e rebuilder s operat e from thei r truck s an

d trave l t o servic e station s replacing worn-ou t nozzl e parts . Othe r rebuilder s ar e large r companie s wh o rebuil d an d tes t th e nozzle s the yrebuil d t o mee t give nspecifications . Recently , primarymanufacturer s hav e becom e mor e concerne d abou t th e liabilit yo f rebuil t nozzle s sinc e theycoul d b e hel d responsibl e fo r a failur e o f a rebuil t nozzl e wit hthei r origina l casting.[20 ] Becaus e o f thi s concern , on e origina l manufacture r ha s qui t rebuilding nozzle s an d ha s trie d t o preven t other s fromrebuilding thei r origina l nozzles . I Wit hrespec t t o th e implementatio n o f a nin-us e dispensin g rat e limit , i t i s importan t t o characteriz e wha t cause s th e variatio n i ndispensin g rates . Th e flo wrat e from th e nozzl e spou t i s dependen t o n tw o factors : th e pressur e supplie d t o th e nozzl e b

yth e pum

p an d th e pressur e a t th e orific e create d b yth e hand leve r positio no nth e nozzle . Thes e combin e t o for ma pressur e dro p whic hgovern s th e flowrat e throughth e nozzle . Th e same nozzl e ca nproduc e a variet yo f flowrate s depending o nthi s pressur e drop . Fo r an ygive nnozzl e configuration , th e maximu mpressur e dro p i s controlle d byth e supplie d pum

p pressur e sinc e th e nozzl e characteristic s ar e fixed . Th e maximu mdispensing rate s o f differen t manufacturers ' nozzle s varywit hth e supplie d pum p pressur e du e t o differen t nozzl e characteristics . Thus , t o contro l th e maximu m flo wrat e throughth e nozzle , th e resulting pressur e dro p create d b

yth e pum

p an d th e leve r positio nmus t b e controlled . Thi s coul d b e don e bycontrollin g th e pressur e contributio no f bot hth e pum p an d th e leve r position . Abetter ' solution , however , i s usin g a variabl e flo wlimiting orific e o r flo wrestricto r t o limi t th e flo wrate . Thi s woul d contro l th e wid e varianc e i n dispensin g rate s tha t coul d occu r wit h differen t combination s o f pum p pressure s an d nozzl e configurations .P.1 7 -16

- A s mentione d above , i norde r t o limi t th e dispensin g rat e a flo wrestricto r o r limiting orific e woul d hav e t o b e incorporate d somewher e i nth e dispensing system . Thi s flo w restricto r coul d b e locate d i nth e dispensing unit , th e hose , o r th e nozzl e itself . Th e in-us e effectivenes s o f th e dispensin g limi t regulatio nmaydepend t o some degre e o nth e restricto r location . Th e bes t locatio nwoul d b e on e wher e th e restricto r provide s effectiv e dispensing rat e control , eas y installatio nan

d resistanc e t o tampering . Inserting th e restricto r o r limiting orific e interna l t o th e nozzl e body appear s t o b e th e bes t wa yt o achiev e thes e requirement s an d thu s ma yb e th e bes t approac ht o contro l dispensin g rates . Ther e ar e basicall ytw o implementatio n approache s fo r a n in-us e dispensin g rat e limi t requirement . First , al l gasolin e retailer s an

d wholesal e purchaser-consumer s coul d b e require d t o limi t dispensing rate s a t th e nozzl e t o n o greate r tha n1 0 gpm . I t place s responsibilit yfo r complianc e wit hth e dispensin g rat e limi t o nth e gasolin e retailer s an d wholesal e purchaser-consumers , thos e wh o ow nan d maintai nth e in-us e fue l nozzles . Thi s optio nallow s tha t n o actio nb e take ni f th e dispensin g rat e limi t requiremen t i s bein g me t withou t an y modification s an

d als o provide s flexibilit yo nho wcomplianc e i s achieve d whe nmeasure s ar e neede d (i.e. , nozzle , pump , o r hos e restrictor) . j Th e second implementatio nmetho d considere d woul d b e t o requir e tha t nozzl e manufacturer s designthei r nozzle s s o tha t th e maximu

m dispensing rat e woul d no t excee d 1 0 gpm . Unde r thi s approach , nozzl e manufacturer s woul d probabl yhav e t o verif ycomplianc e wit hth e dispensing rat e regulatio nthrough anEP Acertificatio n program . Th e gasolin e retailer s an d wholesal e purchaser-consumer s coul d the npurchas e certifie d nozzle s fo r dispensing gasolin e a t thei r facilities . Thi s alternativ e woul d guarante e tha t th e flo wregulato r wa s par t o f th e interna l nozzl e designan d als o woul d insur e th e availabilit yo f a produc t whic hconform s t o th e 1 0 gpm dispensin g rat e limit . However , thi s implementatio n approac h ha s severa l drawbacks . First , i t put s a t leas t par t o f the , liabilit yfo r controlling in-us e dispensing rate s o nth e nozzl e manufacturers , wh o ar e no t responsibl e fo r th e maintenanc e o r conditio no f th e nozzle s i nuse . Second , thi s optio nwoul d forc e EP At o regulat e a ne windustry , th e nozzl e manufacturers , whic hcoul d hav e some economi c implication s o nsmal l business . Third , unde r thi s approac hi t woul d b e necessaryt o provid e a phase-i n perio d fo r th e effectiv e dat e o f a dispensin g rat e limi t t o preven t a massiv e turnove r o f fue l nozzle s a t th e servic e stations . Finally , thi s optio nwoul d mak e rebuilders , whic har e fo r th e mos t par t smal l businesses , us e a differen t approac hi norde r t o stayi nth e market . The ywoul d hav e t o certif yeac htyp e o f nozzl e the yrebuild . Thi s coul d substantiall yalte r thei r busines s an d marketin g operations .P.1 8 -17

- Base d o nth e discussio nabove , th e mos t straightforwar d approac hi s th e firs t optio nwhic hrequire s tha t gasolin e retailer s an

d wholesal e purchaser-consumer s dispens e gasolin e a t a maximu

mflo wrat e n o greate r tha n1 0 gpm . Thi s approac h ha s severa l advantages . First , thi s optio n minimize s complianc e cost s sinc e mos t servic e station s woul d alread yb e i ncomplianc e an

d woul d no t hav e t o tak e an yaction . I f th e maximu mflo wrat e fo r a nozzl e exceed s 1 0 gpm , however , th e restricto r o r limiting orific e discusse d above woul d nee d t o b e place d i n th e systemt o limi t flow . Second , thi s optio nwil l no t forc e EPAt o regulat e a ne w industryo r hav e an ynegativ e impact s o nsmal l business . Fo r marketin g reasons , however , bot horigina l nozzl e manufacturer s an d rebuilder s coul d choos e t o modif ythei r produc t design s t o fulfil l thi s in-us e dispensing rat e limi t requirement . Origina l manufacturer s coul d eithe r modif yth e poppe t i nthei r curren t nozzle s t o ac t a s a limiting orific e o r inser t a flo w regulato r (variabl e orifice ) i nth e nozzle . Rebuilders , whic h us e th e origina l nozzl e bodies , coul d ad d a fixe d o r variabl e flowregulato r i f th e origina l nozzl e wa s no t alread ydesigne d t o compl ywit hth e dispensin g rat e limit . Third , thi s optio ni s preferabl e fro man enforcemen t perspective . Existin g enforcemen t program s a t bot hth e statj e an d federa l level s coul d easil yb e expande d t o includ e a maximu m dispensin g rat e measurement . Th e tes t procedur e use d t o determin e th e flo wrat e woul d consis t o f eithe r anin-lin e flowmete r o r a volume/tim e measurement . Finally , th e liabilit yfo r complianc e wit hth e 1 0 gpm maximu mdispensin g rat e requiremen t woul d li e wit hth e gasolin e retailer s an

d wholesal e purchaser-consumers . Th e liabilit y provision s coul d b e simila r t o thos e applie d t o th e curren t nozzl e spou t diamete r regulation s fo r leade d an d unleade d fuel s (4 0 CF R80.23) . VII . Economi c Analysi s Th e economi c impac t o f a nin-us e dispensin g rat e limi t requiremen t i s expecte d t o b e minimal . Sinc e th e 1 0 gp mvalu e wa s chose nfromvalue s nea r th e hig hen d o f th e curren t dispensin g rat e range , mos t station s ar e no wi ncomplianc e withou t an

yadditiona l modification s and wil l incur n o costs . Therefore , th e primaryeffec t o f anin-us e dispensin g rat e limi t woul d b e o ncurren t servic e station s whic har e dispensin g a t rate s highe r tha n1 0 gpm , ne wservic e stations , an d servic e station s whic hwil l replac e thei r curren t underground pump s an d dispensin g hardwar e i nth e future .P.1 9 -18

- Fo r thos e curren t servic e stations/nozzle s whic har e dispensin g a t rate s highe r tha n1 0 gpm , some modification s woul d b e necessaryt o attai ncompliance . The ycoul d retrofi t thei r dispensin g hardwar e t o satisf yth e dispensin g rat e limi t byinserting a flo wregulato r i nth e hose , dispenser , o r nozzle . I nth e futur e the ycoul d purchas e ne wo r rebuil t fue l nozzle s whic hhav e a fixe d o r variabl e flo wregulato r an d ca n effectivel yregulat e dispensin g rates . Fo r ne wservic e station s an d thos e station s whic hwil l replac e thei r curren t underground pump s an d dispensin g hardwar e i nth e future , equipmen t the yinstal l wil l hav e t o compl yt o th e 1 0 gpmdispensing rat e requirement . I f thei r equipmen t exceed s th e 1 0 gp mrequirement , the ycoul d eithe r inser t flo w regulator s i nthei r equipmen t (i.e. , dispense r o r hose ) o r purchas e nozzle s whic har e designe d specificall yt o contro l th e maximu m dispensin g rat e t o 1 0 gpm . Furthermore , thes e station s woul d no t nee d t o instal l underground pump s o f highe r horsepowe r tha n thos e currentl yuse d sinc e th e dispensing rat e woul d b e regulate d an d th e increase d horsepowe r woul d provid e littl e o r n o additiona l benefits . Thu s bot hcapita l an d operatin g cost s relate d t o th e pum p coul d b e saved . Base d o n th e discussio nabove , i t appear s tha t th e simples t an

d mos t effectiv e wa yt o regulat e th e dispensiri g rate s fo r fo r curren t an d futur e station s woul d b e through nozzl e modifications . Th e cost s associate d wit hthes e nozzl e modification s ar e discusse d below . A s wa s mentione d previously , ther e ar e tw o way s t o effectivel yregulat e fue l flo wi nth e nozzle : 1 ) modif yth e existin g poppe t i nmos t curren t nozzle s t o serv e a s a limiting orifice , o r 2 ) inser t a flo wregulato r i n th e nozzle . Modifyin g th e existing nozzl e desig nwoul d requir e onl ymino r toolin g change s i nth e productio no f th e nozzles . Thes e toolin g change s woul d cos t approximatel y$ 1 pe r nozzl e t o amortiz e th e necessaryfixe d cost s neede d fo r thes e changes . Thes e toolin g chang e cost s ar e onl yshort-terman d woul d b e eliminate d afte r a fe wyears . Inserting a flo wregulator, , however , woul d provid e bette r contro l o f dispensin g rate s ove r a wide r pressur e range . Base d o ndiscussion s wit hnozzl e manufacturers , th e flo wregulato r an d necessarytooling change s ar e estimate d t o cos t betwee n$ 1 an d $ 5 pe r nozzle . [21,22 ] Therefore , th e hardwar e an d tooling cost s fo r origina l manufacturer s t o incorporat e a nin-us e .dispensing rat e limi t int o thei r nozzl e design s wil l rang e from$ 1 t o $ 5 pe r nozzl e dependin g o nth e typ e o f contro l th e manufacture r choose s t o implement . Rebuilder s hav e onl yon e alternativ e t o effectivel y regulat e dispensin g rate s i nth e nozzle . Thi s alternativ e i s t o inser t a fixe d o r variabl e flo wregulato r i nth e interna l desig no f th e nozzle . A s state d above , th e hardwar e cost s necessar yt o incorporat e thi s flo wregulato r int o th e nozzl e desig nrange s betwee n $ 1 an d $ 5 pe r nozzle .P.2 0 -19

- Base d o nthi s discussion , th e economi c burde no f a dispensin g rat e limi t requiremen t woul d b e expecte d t o b e ver y low . Sinc e th e flo wrat e limi t wa s selecte d fromnea r th e hig h end o f th e curren t in-us e dispensin g rat e range , mos t station s woul d alread

ymee t thi s requiremen t an d therefor e incur n o associate d cost . I n addition , i t i s wort hnotin g tha t an y additiona l cost s t o th e consume r relate d t o limiting dispensin g rate s coul d b e substantiall yoffse t b yth e reductio ni n spitbac k spillag e whic hma yresult . VIII . Summaryan d Conclusion s Fromth e discussio no f th e issue s studire d i nthi s investigation , anin-us e dispensin g rat e limi t woul d enhanc e th e onboar d effectivenes s an d reduc e spitbac k cause d by prematur e nozzl e shut-offs . Suc ha limi t woul d ensur e tha t th e maximu min-us e dispensin g rate s ar e equivalen t t o th e dispensin g rate s use d i nth e desig nan d certificatio n o f th e vehicle' s refueling contro l system . I t mayals o b e beneficia l t o specif ynozzl e geometrie s t o assis t i ncontrollin g refuelin g emission s an

d preven t spillage . Furthe r informatio nregardin g th e impact s o f nozzl e geometrie s o nrefueling emission s an d onboar d systemdesigns , however , i s neede d befor e suc h standardizatio ni s considered . I Sectio n21 1 (c ) o f th e Clea nAi r Ac t give s EPAth e authorit yt o regulat e th e dispensin g rate s an d geometrie s o f fue l nozzles . Adispensin g rat e limi t requiremen t woul d enhanc e th e performanc e an d efficienc yo f onboar d control s a s wel l a s provid e additiona l refueling emissio nreduction s an d gasolin e saving s b yreducing spillage . I naddition , th e reductio ni ngasolin e spillag e wil l provid e severa l healt hand safet yimprovement s fo r refueling operations . Arecommende d approac hfo r a dispensin g rat e limi t woul d requir e tha t al l commercia l gasolin e retailer s and wholesal e purchaser-consumer s us e nozzle s wit ha maximu mdispensin g rat e o f 1 0 gpm . Federa l an d stat e surveillanc e team s woul d hav e t o expand thei r enforcemen t program s t o measur e th e maximu mdispensin g rat e a t servic e stations . Furthermore , suc hregulation s shoul d hav e ver ysmal l economi c impac t sinc e mos t station s woul d alread yb e i ncomplianc e wit hth e dispensin g rat e limit . I nconclusion , i t appear s tha t developmen t o f anin-us e dispensin g rat e limi t i s i norde r t o ensur e prope r functionin g o f onboar d contro l system s an d reduc e in-us e gasolin e spillage . Th e benefit s receive d from , suc ha regulatio n outweighan

ycost s whic hma yresult . I naddition , furthe r investigatio no f th e effect s o f nozzl e geometrystandardizatio n shoul d b e furthe r studie d fo r th e same reasons .P.2 1 -20

- Reference s 1 . Memorandu

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mMarketin g IndustryRefuelin g Rat e Voluntary Standard, " Augus t 6 , 1986 . 3 . "Investigatio no f Passenge r Ca r Refuelin g Losses, " Malcol mSmith , Scot t Researc hLaboratories , Inc. , Septembe r 1 , 1972 . 4 . " AStud yo f Variable s tha t Effec t th e Amoun t o f Vapo r Emitte d Durin g th e Refueling o f Automobiles, " Edwar d M . Liston , Stanfor d Researc hInstitute , Ma y16 , 1975 . 5 . Memorandu

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- Nozzl e Spout s fo r Unleade d Gasoline, " ISO/TC22/SC16/WG3/N24 . 13 . "Anne xwit hU.S . Disapprova l t o N7 4 an d N75, " R . Thoma s Northrup , Societ yo f Automotiv e Engineers , Novembe r 14 , 1985 . 14 . Produc t Catalog s an d Subsequen t Telephon e Conversation s wit hDove r Corp./OP WDivisio nregarding nozzl e spou t dimensions , Jul y1986 .

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15 . Produc t Catalog s an d Subsequen t Telephon e Conversation s wit hEMC O Wheato nregarding nozzl e spou t dimensions , Jul y1986 . 16 . Performanc e Tes t Procedure s fo r Gasolin e Vapo r RecoverySystems , StationarySourc e Tes t Methods , February1984 . 17 . "M0BILE 3 Fue l Consumptio nModel, " Mark . Wolcott , EPA-AA-TEB-85-2 , February1985 . 18 . "Evaluatio no f Ai r Pollutio nRegulatoryStrategie s fo r Gasolin e Marketin g Industry- Respons e t o Publi c Comments, " Draf t RI A(Vol . 1) , Novembe r 5 , 1986 . 19 . Patty' s Industria l Hygien e an d Toxicology , G. D Clayto nan

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mEquipmen t Institute , Jul y1986 . 21 . Memorandu

mt o Kathlee nSteile nfromHusky Corporation , Arthu r C . Fink , Jr. , Marc h3 , 198 7 an d Subsequen t Telephon e Conversatio n o nMarc h6 , 1987 . 22 . Conversatio nwit hAle xPodger s o f EMC O Wheatoi| , Meetin g wit hNozzl e Manufacturer s fromPetroleu m Equipmen t Institute , Septembe r 23 , 1986 .