# OAR Box 1830

Prepped by Ollie Stewart



### Document

Number: 

# 35 ) IV-C- 1 Docket Number: 

# A-87-1 1

Printed 11/13/20087:20:52 AM Sheet 35of 232 p. 1P. 2

^ # % T i UNITE D STATE S ENVIRONMENTA L PROTECTIO N AGENC Y 

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MS*' AN N ARBOR . MICHIGA N 4810 5 

### MJ 6 2T198 7 OFFIC E O F AI R AN D RADIATIO N

Mr . Willia

m F . Marshal l Manager - Fuels/Engine s Researc h Nationa l institut e fo r Petroleu

m an dEnerg y Research P.O . Bo x212 8 Bartlesville , O

K7400 5 Dea r Mr . Marshall : Thank s ver

y muc hfo

r providing u

s a cop y of you r proposa l t o th e Citizen s fo

r Improve d Ai r Qualit yfo r quantificatio

nof emptyin g losses . W

e appreciat e the opportunit y t o provide thes e comment s an

dsuggestion s on your tes t plan . Th e thought s her e focu s primaril yon your actua l approac ht o measurin g undergroun

d tan k emission s (Task 2) . T o assis t yo u i n responding t o Tas k 1 , yo u shoul d have alread yreceive d a copy o f the 196 2 count yo f Lo s Angele s APC D repor t whic h serve s a s the basi s fo r the curren t uncontrolle d emissio n factor , pleas e not e tha t thi s facto r actuall yrepresent s the su mo f bot h breathing an

d emptying losse s fro mthe undergroun

d tank . No attemp t wa s mad e t o discriminat e betwee n the two type s o f emissions
. However , th e assertio n i s tha t Stag e I I woul d reduc e onl yemptying losses . Turning nowt o Tas k 2 , we hav e a fewspecifi c comment s on your tes t plan an

d a fe wgenera l thoughts . First , i f possible , th e approac hused shoul d allowfor differentiatio n betwee n breathing an

d emptying losses . Thi s ma yb e difficul t fo r severa l reasons . Bot htype s o f emission s emanat e fro mthe ven t tube , an

d ther e i s probabl yn o easywa yt o physicall yo r chemicall ydiscriminat e betwee n them . Also , th e timing o f the emission s i s somewha t unpredictable
. Determinatio n o f emptying losse s ma

yrequir e an approac hin whic hcombine d breathin g an d emptying losse s ar e measure d i n on e progra man d breathin g losse s alon e (n

o refuelings ) ar e measure d in a secon d progra

m an d the tw

o value s subtracted . O f course , designin g an approac hsuc ha s thi s woul d requir e extreme car e t o b e sur e tha t condition s an d variable s i n the two program s ar e essentiall yidentical
.P. 3


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- Second , i n term s o f th e underground storag e tank itself , you r underground storag e tank volum e i s a t th e lowen d o f th e presen t range , o f in-us e tank s an d thu s coul d affec t th e representativenes s o f th e emissio n results . I n th e field , curren t underground tank s rang e i n volum e from4,000-6,00 0 gallon s fo r olde r station s t o 8,000-12,00 0 gallon s fo r newe r stations
. Thi s i s importan t becaus e th e emission s coul d b e affecte d b

yth e tank. , dimension s (whic haffec t th e shape , volume , an

d liqui d surfac e area) , th e number , lengt han d diamete r o f th e ven t tubes , an d th e point s a t whic hth e ven t tube(s ) an

d Stag e I I returne d vapor s ente r th e tank . Mos t tank s ar e cylindrica l i n shap e wit ha lengt h greate r tha n thei r diamete r an

d li e o n thei r sid e thu s creating a larg e liqui d surfac e are a an

d a shor t distanc e betwee n th e liqui d leve l an d th e ven t tub e outle t fro mth e tank . Third , th e undergroun d tank fue l level , an d RV P a s wel l a s th e fue l an

d vapo r temperatur e woul d affec t emissions
. You r tes t plan shoul d specificall yinclud e provision s fo r monitorin g th e RVP o f th e fue l i n th e underground tank . Monitorin g a t th e beginning o f eac hdayo f testin g woul d b e advisable
. O f course , an initia l fuel/vapo r equilibriu mmus t exis t i n th e underground tank befor e beginnin g an ymeasurements . Fourth , you r tes t pla n shoul d specificall yaddres s dispensing rates , th e frequenc yo f refueling events , an d th e amoun t o f fue l t o b e dispense d durin g eac hrefuelin g even t sinc e thes e factor s ar e likel yt o affec t emissions
. Hig han d lowboun

d value s mayb e a usefu l approach . Also , sinc e emission s coul d occu r eve n whe n th e pump s ar e closed , emissio n measurement s shoul d b e take n continuousl y(2 4 hour s a day ) ove r a numbe r o f day s fo r eac hcondition
. Testing ove r a numbe r o f day s woul d als o accoun t fo r an ymeteorologica l effect s (temp , pressure , relativ e humidity ) on emissions
. Fifth , whe n evaluating th e effec t o f Stag e I I control s o n emissio n rate s you r tes t pla n shoul d ensur e tha t th e fuel/vapo r i n the experimenta l fue l tan k i s typica l o f tha t whic hwoul d b e expecte d fo r thos e ambien t conditions
. Fue l i n th e experimenta l tan

k shoul d b e 5 t o 1 0 ° F warme r tha n ambien t temperatur e an

d weathere d approximatel y0. 5 - 1. 0 ps i a s compare d t o th e fue l being dispensed
. Also , th e tes t approac h use d shoul d ensur e tha t th e vapo r spac e i n th e experimenta l tan k i s saturate d befor e fue l i s dispensed
. Thi s wil l ensur e tha t th e vapor s returne d t o th e underground tank ar e typica l o f tha t expecte d i n th e field , an d wil l allo wth e emissio n effect s o f vapo r cooling an d liquid/vapo r equilibriu m fo r al l th e specie s t o occur . A s par t o f an yexperimen t i t woul d b e importan t t o hav e an ide a o f th e efficienc yo f th e Stag e I I syste m being used .• - * - -3

- Fmally , a fe wothe r thoughts . First , you r instrumentatio n approac hlook s good ; i t shoul d allo wcontinuou s monitorin

g o f th

e ven t outlet . Second, , i t migh t b e worthwhil e t o speciat e th e liqui d fue l an d sample s o f th e underground tank vapor , breathing/emptyin g losses , an d th e vapo r returne d t o th e underground ? tank from th e experimenta l tank durin g th e Stag e I I portio n o f th e program . Thi s informatio n coul d prov e usefu l i n an ylate r analyses . Also , sinc e th e instrumentatio n an d othe r apparatu s ar e alread yse t up , i t woul d definitel yb e worthwhil e t o measur e breathin g los s emission s alon e (no refuelin g events ) an d breathing/emptyin g los s emission s wit ha pressure/vacuu m valv e o r limiting orific e withi n th e ven t tub e t o contro l emissions
. Thi s coul d prov e t o b e a ver yinexpensiv e contro l technique
. I hop e thes e idea s ar e useful . i f w e ca n provid e an y furthe r idea s o r informatio n pleas e contac t Glenn Passavan t o f m ystaf f a t 374-840 8 (FTS) . Sincerel yyours , ORIGINA L SIGNE D BY CHARLE S L GRAY , JR . Charle s L . Gray , Jr . Directo r Emissio n Contro l Technolog yDivisio n

cc : Ter i Richman , Citizen s fo r Improve d Ai r Qualit y Docke t A-87-1 1