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# OAR Box 1147 Prepped by Ollie Stewart



### Document

Number: 

# 157 ) IV-E-30 Docket Number: 

# A-87-1 1

Printed 4/22/2008 2:42:56

PM Sheet 157 of 242_-» . sft «5 f 

# USB J UNITE D STATE S ENVIRONMENTA L PROTECTIO N AGENC Y AN N ARBOR . MICHIGA N 4810 5 P. 2



### MA R 9(98 8 OFFIC E O F AI R AN O RADIATIO N

MEMORANDU

M SUBJECT :

FROM : Contac t Wit h G M Concerning Vide o Tap e o f Onboar d Tes t Fir e Joh n F . Anderson , Senio r Projec t Manage r Standard s Developmen t an d Suppor t Branc h y TO : THRU : Docke t A-87-1 1

Cheste r J . Frknce , Chie f Standard s Developmen t a n ranc h On February26 , 198 8 I spok e wit h Mr . Ji mPase k o f G M an d Mr . Rober t Lang o f Failur e Analysi s Associate s (FAA ) concerning the tes t whic h FA Aha d performe d for G M evaluating th e possibilit yo f underhoo d fire s fro m damage d refueling systems . FA Ahad apparentl ydetermine d tha t a fir e coul d b e starte d fro m a disconnecte d refueling ven t line whe n re-route d an d place d nex t t o a defectiv e spark plug wir e capabl e o f producing a spark upo n vehicl e startup . I n the tes t sequence , th e refuelin

g vapo r hos e wa s disconnecte d fro

mthe refuelin

g canister , whic h ha d bee n locate d unde r the hood , an d re-route d s o a s t o en d immediatel y adjacen t t o a damage d spark plug wire . Th e vehicl e wa s refuele d wit h 1 5 gallon s o f fuel , th e nozzl e wa s returne d t o th e fue l dispenser , an d the vehicl e subsequentl ywa s restarted . I n a vide o tap e o f th e hos e outle t unde r the hood , th e vapo r surrounding th e en d o f th

e hos e wa s seen t o ignit e upo n engin e engagement . Th e vapo r continue d t o burn fo r the approximatel y6 second s o f filming . I n addition , the hos e itsel f began t o burn almos t immediately . I ha d contacte d G

M t o as k howi t wa s tha t vapor s appeare d t o continu e t o flowfro mth e hos e eve n thoug h th e refuelingP. 3

even t ha

d ende d an

d the vapo r chec k valve wa s closed . Mr . Lang , who; : wa s th e enginee r a t FAA ' responsibl e fo r th e tests , firs t assure d m e tha t th e vehicl e wa s no t being refuele d during th e engin e star t sequence . H e the n suggeste d tha t th e vapor s flowing i n th e lin e during the refueling had sufficien t inerti a s o a s t o continu e t o flowwhil e th e engin e wa s being started . H e als o stated * tha t the combustio n proces s woul d creat e a vacuu m a t th e en

d o f th e hos e an

d drawthe vapor s ou t o f th e line . I foun

d neithe r o f thes e answer s satisfactorybecaus e o f th e fac t tha t th e vapo r cu t valv e o n the othe r en d o f th e lin e fiad bee n close d sinc e th e en d o f the refueling operation . Mr . Pase k the n suggeste d tha t perhap s th e evaporativ e ven t orific e wa s venting residua l tan k pressur e int o th e hose , sinc e th e liqui d sea l woul d preven t ful l tan k depressurizatio n immediately . Thi s explanatio n seem s improbable . Ventin g a t the

- high rat e see n i n th e vide o woul d hav e equilibrate d th e tan k i n a fewseconds , mos t likel ybefor e th e engin e star t sequenc e eve n began . I f th e venting wer e slow , the n i t i s difficul t t o understan

d ho wthe larg e bur n rat e wa s sustained . However , on th e assumptio n tha t thi s wer e a possibl e mechanism , i t i s apparen t tha t muc h highe r vapo r flowrate s coul d occur fro m curren t fue l tan k ven t line s during period s o f vehicl e operatio n a s fue l tan k temperature s increased . Th e flowwoul d b e highe r becaus e th e tan k pressure s woul d b e muc h higher . Th e liqui d sea l systemproduce s tan k pressure s o f a t mos t a few inche s o f water' , whil e pressure s i n operating fue l tank s can be i n the 2 0 t o 4 0 inc h range . Thus , the hazar d fro msuc h a defec t mod e woul d appea r t o b e greate r wit h curren t vehicle s than fro

m refueling systemadditions . G M di d no t agre e tha t evaporativ e ven t vapor s coul d b e ignited . Mr . Lang argue d tha t th e vapo r flowwoul d neve r be sufficien t t o produc e a combustibl e mixture , although h e agree d tha t a flammabilit yzone ha d t o exis t somewher e betwee n the insid e o f th e en

d o f th e hos e an

d th e ambien t air . Whil e being unabl e t o explai n thi s discrepancy , Mr . Lang maintaine d tha t evaporativ e emission s woul d no t reach a combustibl e stat e during such venting . H e als o argue d tha t i t woul d tak e a larg e poo l o f residua l vapors , suc h a s woul d exis t following refueling , t o initiall yignit e the vapor s or tha t ai r flow unde r the hoo d whil e driving woul d blowth e vapor s awa ybefor e the ycoul d ignite . However , he als o agree d tha t a smal l flo w o f butan e a s foun d i n man

ycigarett e lighter s wa s eas yt o ignit e wit h a smal l spark . Our discussio n wa s ende d a t thi s poin t becaus e Mr . Pase k indicate d tha t h e had t o leav e fo r a meeting . Mr . Pase k als o decline d t o submi t a writte n explanatio n o f howG M believe d the vapo r flowfromth e hos e wa s sustained .