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# OAR Box 1313 Prepped by LaTeia Shed



### Document

Number: 

# 48 ) ll-B-2 2
Docket Number: 

# A-88-0 2

Printed 6/12/20089:03:29AM

Sheet 48of 99

# ® PJ L 

## A-88-02 MIDWES TRESEARC H INSTITUT E

450 5 Creedmoo rRoa

d Raleigh , N.C
. 2761 2 Telephon e (919

) 781-5750 i- . ' . ' ; "

• ' 7

Date : Marc h16 , 198 7

(Finalize dApri l 2 , 1987 ) Subject : Sit e V1 sit—Prat t an dWhitne y Chromiu m Electroplatin g NESHA P EPA Contrac t 68-02-3817 ; ESE DProjec t 85/02 a MR I Projec t 7717- K From : To : Robi nBarke r



# $Y

Al Vervaer t ESED/ISB/SS S (MD-13 ) U . S . Environmenta l Protectio nAgenc y Researc hTriangl e Park , N.C . 2771 1 I . Purpos e Th e purpos e o f thi s sit e visi t wa s t o gathe r backgroundInformatio n abou t th e chromi c aci danodizin g operation s a t thi s plan t an dt o asses s visuall y th e amoun t o f mistin g fro m th e tw o chromi c aci danodizin g tanks . II . Plac e an

dDat e Prat t an

dWhitne y 40 0 Mai nStree t Eas t Hartford , Connecticu t 0610 8 (203 ) 565-201 6 Decembe r 17 , 198 6 III . Attendee s Prat t an

dWhitne y

* JohnL . Russell , Plan t Enginee r U . S . Environmenta l Protectio nAqenc y (EPA ) Al Vervaert , IS B Midwes t Researc hInstitut e Robi nBarke r

/P. 3

IV . Discussio n W e arrive da t th e plan t a t 1:3 0 p.m . Durin g th e visit , ther e wa s a discussio nabou t th e chromi c aci danodizin g operation s followe db y a tou r o f th e facility . A . Genera l Prat t an dWhitne y

i s a captiv e sho ptha t perform s chromi c ad d anodizin g o f aircraf t part s suc ha s gearboxes . Th e facilit y employ s 11,00 0 peopl e an

doperate s 2 4 hour s pe r day , 6 day s pe r week . Th e operatio no f th e anodizin g proces s 1 s variable , dependin g upo nth e amoun t o f wor krequirin g anodizing . B . Proces s Description s Ther e ar e tw

o Identica l anodizin g tank s a t thi s facility . Eac htank 1 s 2. 1 meter s (m ) ( 7 fee t [ft] ) long , 2. 1 m ( 7 ft ) wide , 2. 1 m

( 7 ft ) dee p an dhold s 10,14 5 liter s (2,68 0 gallons ) o f anodizin g solution . Th e anodizin g solutio ncontain s chromi c aci di na concentratio no f approximatel y

12 0 gram s pe r lite r (g/a ) (1 6 ounce s pe r gallo n[oz/gal] ) o f water . Th e operatin g temperatur e 1 s 60° C (140°F) . Th e tank s ar e equippe dwit hmanua l rectifier s tha t ar e use dt o ste p th e voltag e t o 2 0 o r 4 0 volt s ove r a 30-m1nut e period . (The voltag e use d depends upo nth e typ e o f par t being anodized. ) Th e voltag e 1 s the n maintaine da t 2 0 o r 4 0 volt s fo r th e remainde r o f th e anodizin g time . Th e anodizin g time typicall y range s fro

m 4 0 t o 9 0 minutes . Th e curren t applie ddurin g th e anodizin g tim e range s fro

m 20 0 t o 40 0 amperes . Th e facilit y

ha s fiv e othe r tank s tha t contai nchromi c add . Thes e tank s ar e use dt o stri pth e aluminu m substrat e an

dt o sea l th e aluminu m afte r anodizing . Th e chromi c aci dconcentratio no f th e solutio ni nthes e tank s range s fro

m 7. 5 t o 12 0 g/ a ( 1 t o 1 6 oz/gal ) o f water . C . Emissio nContro l Bot hanodizin g tank s ar e equippe dwit hsingle-side dlatera l hood s t o captur e an

y chromi c aci dmis t tha t may be generate dduring anodizing . Ther e ar e no contro l device s i nplac e t o trea t th e ventilatio nexhaus t gases . V . Observation s Prat t an dWhitne y

i s representativ e o f othe r captiv e anodizin g shops . A t th e time o f th e visit , th e anodizin g tank s wer e no t 1n operatio ns o n o visua l assessmen t o f th e amoun t o f mistin g coul db e made .



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