Document j2VvJLLXBrLymbqgJ50qg35k

ETHYL CORPORATION Inter-O ffice M r. W. F . A r m s t r o n g M r. J. J. B ergin M r. T. C. C o erv er M r. H. w . Hobgood M r. D. E . P a r k *0si . &. . TO: M r. L. L. Reynolds FROM: R. H. J o n e s SU B JECT: L ead C ontam ination Study - T E L A r e a . .. . , M ay 30, 1966 Introduction A study w as begun in F e b ru a ry , 1966 to d e te rm in e the so u rces of lead contam ination in the T E L a r e a and to d e te rm in e w hat steps should be taken to reduce the contam ination h azard . The p u rp o se of this re p o rt is to su m m a riz e the in form ation obtained to date and to reco m m en d steps to r e duce the lead contam ination hazard. B ackground inform ation is filed in "1966 A ir Contam ination" file. . P a rtic u la r em phasis during this study has been placed on the lead contam ination p roblem in -"C " M anufacturing Building, w here contam i nation is m o st severe. Some studies have also been done in "B " Building and in the alloy area. i The principal sources of lead contam ination which have been discovered a re listed below along w ith suggestions for elim inating o r r e ducing the lead concentration in operating area s. 1 A list of recom m endations is included at the end of this report. "C " BUILDING . 5th Flotar 1. , Alloy H oppers - Spot a ir sam ples underneath em pty hoppers o n th e 5 th f lo o r an d in th e tu n n e l a v e r a g e d 1. 27 m g / f t . 3 ( T a r g e t m a x im u m c o n c e n tra tio n is 0. 002 m g / f t . 3 ) T h e r e is a ls o an indication th at n o rth e rly w inds c au se contam ination on the 5th flo o r by blowing into the.b u ild in g through the opened doors at th e north end of the 5th floor, th ereb y picking up lead vapors fro m the em pty contam inated hoppers w hich a re stored there. - Liquid .has been observed; underneath em pty hoppers on the 5th floor and in the tunnel on num erous occasions. :- A sy stem has been designed for purging the hoppers with nitrogen w h ile alloy is ch arg ed to the au to clav es. T his should p rev en t contam inated vapors fro m entering the hoppers fro m the auto claves , thereby . reducing the contam ination fro m em pty hoppers. Installation of this nitrogen purge sy stem should be expedited. C om m unication fro m 4th F lo o r - A ir c u rre n ts upw ard fro m th e highly contam inated 4th floor n ear the w alls w as found to be a m a jo r so u rce of contam ination on the 5th floor. It w as also found th at peaks in lead co n cen tratio n o c c u rre d on th e 5th flo o r d u ring the d isc h a rg e p o rtio n of the au to clav e cycle, i. e. , when the angle valves and slide valves a re open. Also, the lead concentration on the 5th floor w as highest w hen highly contam i n a te d w o rk w as being p e r f o r m e d on th e 4th flo o r, e. g. , D u ra s e a l re p a irs and unplugging drop legs. C o m m unication fro m the 4th flo o r to the 5th flo o r h as been r e duced significantly by m in o r m odifications w hich w e re m ade to th e ventilation sy ste m in A pril. A p o rtio n o f th e supply a ir to the 4th floor w as blocked off and the doors at the north end of th e flo o r have been clo sed to c re a te a g re a te r dow ndraft of a i r fro m the 5th floor. T hese m odifications have in c re a se d the difference in lead concen tratio n betw een the 4th and 5th flo o rs w hich has reduced the contam ination lev el on the 5th floor. T h is i s i l l u s t r a t e d in F i g u r e 1, ' " C 1 B u ild in g L e a d C o n ta m i n atio n ." However, som e com m unication still exists and it m ay be n e c e s s a ry to iso la te the 5th flo o r fro m the 4th flo o r by in stalling a p artitio n betw een the edges of the 5th floor and the building w all. This w ill not reduce the contam ination on the , 4th flo o r but should reduce the contam ination on the 5th floor, which is the m o re inhabited operating area. D isc R uptures - Lead concentration on the 5th floor of "C" B uild in g a v e ra g e s 0. 003 m g/ft.3 g r e a t e r on d ay s w hen d isc ru p tu res o ccu r at "B ", "C", o r "D" Buildings than on days w h en th e re a r e no d isc ru p tu re s . One s e t of spot s a m p le s obtained in "C " Building following a TM L disc rupture showed th a t a s h o rt p e rio d (le s s th an 30 m in u tes) of v e ry high lead co n cen tratio n follow ed the d isc ru p tu re. As shown in F ig u re 3, "L ead C oncentration in 'C 1 Building Follow ing Disc R upture on C - 17 A u to c la v e " , le a d c o n c e n tra tio n d e c r e a s e d ra p id ly f r o m a v ery high level im m ed iately following the ru p tu re. The con cen tratio n then d ecreased gradually until the ruptured disc w as rem oved from the disc line. At thia tim e, the concentration in c re a s e d rap id ly to a v e ry high le v e l as. a re s u lt o f th e hot vapors fro m the autoclave rising to the 5th floor w hen the disc flange was opened. .- . '. .. - 3 - . - / A dditional data w ill be obtained following future disc ruptures. 4. ; Alloy C harging - Spot a ir sam ples indicate that little o r no con tam ination occurs during charging. This is probably due p rim a ri ly to the highly efficient charging head a ir exhaust system . N itrogen purging of the hoppers as d iscu ssed previously should . reduce any contam ination which m ight o ccu r during charging.; 5 . C h a r g i n g V e n t V a l v e s r- P a c k i n g g l a n d s o n t h e c h a r g i n g v e n t v a lv e s (1 1 /2 " ) f a il p e r i o d i c a l l y w h ic h c a u s e s s o m e c o n t a m i nation. Six such fa ilu re s w e re re p a ire d in F e b ru a ry , and five w ere rep aired in M arch. T hese leaks could be elim inated by replacing the existing valves with ball valves. ; f. 4th F lo o r . ` ; " 1. 'k. , i Plugged Drop Legs - The biggest cause of lost charges and one of the la rg e st co n trib u to rs to building contam ination is plugged drop legs. P lugged d ro p legs account fo r n e a rly 100 lo st c h arg e s p e r m o n t h w h i c h i s e q u i v a l e n t to a 2 % l o s s i n p r o d u c t i o n -j capacity. It is frequently n e c e ssa ry to rem ove the inspection flange fro m the drop leg to apply fire w a te r p re s s u re to fo rce the plug out of the drop leg and into th e still. This is f r e quently followed by m echanical cleaning of the drop leg. Lead c o n c e n tra tio n s of 0. 02 m g /ft.3 o r g r e a t e r a r e c o m m o n f o r the 4th floor on days w hen plugged drop legs a re cleaned based on * 24-hr. air analyses. Peak concentrations are probably m uch higher. , ' ' \' A te st is cu rren tly in p ro g re ss in which the drop leg on C-2 autoclave is being w ater-flu sh ed b efo re and afte r each d isch arg e of the reaction m ass fro m the autoclave. The drop leg on C -2 au to c la v e plugged w ith an a v e r a g e fre q u e n c y of 0. 85 tim e s p e r week during the period of January th ru M arch. This pluggage r a te h a s d e c r e a s e d to an a v e r a g e fre q u e n c y of 0. 24 tim e s p e r w eek since the w ater-flushing w as begun in A pril. This test w ill continue. W ater-flushing w as recently begun on two ad d i tional drop legs, . A teflon-coated drop leg has been purchased for installation and tria l in TM L s e rv ic e -in "D ". Building. The "n o n -stick " c h a ra c te ristic of teflon is expected to reduce the pluggage frequency. . 2. D u raseal F a ilu re s - D u raseal failu res a re an o th er big so u rce : of lost charges and lead contam ination. D uraseals have been rep laced in ."C" Building at the ;ra te of eight p e r m onth fo r the p ast th re e m onths. M aintenance is cu rren tly looking into a m odified seal design to reduce the num ber of failures. ; -4- ' v . >-=' /V D isc R uptures - The lead concentration on the 4th floor follow ing a disc rupture ap p eared to follow the sam e p rofile as the concentration on the 5th floor w hich w as d iscu ssed previously. T h i s is i l l u s t r a t e d in F i g u r e 3. A lth o u g h th e c o n c e n tr a ti o n p ro files w ere s im ila r fo r the 4th and 5th flo o rs, the co acen tra tio n on the 4th flo o r w as 5 to 20 tim e s h ig h er than the concentration on the 5th floor. N orm ally a ru p tu red disc is rep laced by two p ip efitters. It h as b een o b serv ed th at on two o cca sio n s the p ip e fitte r who rem oved the flange bolts and ruptured disc w ore a fre s h -a ir m ask. How ev er, the o th er p ip e fitter who stood b esid e the autoclave to a s s is t w ore no re s p ira to ry safety equipm ent. Both m en should be req u ired to w e a r f r e s h - a ir m a sk s due to the v ery high lead concentrations which can be p resen t. L ead concentration beside the autoclave was m easu red at 0.368 m g/ft.3 when the ruptured disc was removed. 4. Angle Valve - Slide V alve A ssem bly - Spot a ir sam p les fro m the 4th and 5th flo o rs have shown th a t peaks in lead co n cen tratio n o ccu r when autoclaves a re discharging to the stills. T here a re num erous points on each angle valve and slide valve w here I leaks can develop such as packing glands, g re a se tubing con nections, fittings, and valves, pet cocks, flanges, cover plates, . drain plugs, and w ater flush valves. T hese points a re not exposed to autoclave p re s s u re and hence cannot be leak tested as a re the flanges and valves in the piping asso ciated with the autoclave. . 5. X -m a s Tree V alve C lu s te r - P ack in g gland le a k s o c c u r fre q u e n t- ly on the m ethyl chloride re a r feed valves, nitrogen valves, p rim ary vent valves, and m ethyl chloride feed control valves. The nitrogen valves a re cu rre n tly being converted to b all valves and relo cated to the 5th floor. The r e a r feed valves and the p rim a ry vent valves could be converted to ball valves thus elim inating packing gland leaks. H ow ever, any resulting r e d u ctio n in le a d c o n c e n tra tio n on th e ,4th flo o r w ould p ro b a b ly be insignificant in co m p ariso n w ith the contam ination which is caused by the item s listed previously. 3rd Floor High still p re ssu re caused by back p re s s u re fro m the old TM L reco v ery system (AB-5) w as fo rm erly the p rim a ry cause of contam ination on the 3rd floor. This contam ination has been i greatly reduced since operation of the new TM L recovery 'T s y s te m (A B-9) b eg an on A p ril' 3v T h is im p ro v e m e n t is show n i n F i g u r e 1. S i n c e s t a r t - u p o f A B - 9 , t h e l e a d c o n c e n t r a t i o n on the 3rd floor has averaged only 0.0017 m g/ft. 3 g re a te r than 5- ; . :\ the supply a ir to " O ' B uilding, excluding days on which d isc ru p tu re s o r em ergency vents occurred.- - Spot a ir sam ples obtained with AB-9 operating indicate that little if any leakage is o ccu rrin g at the Sylphon seals on the stills o r at the flush-out connections on the still receivers. E lev ato r - The elevator in " O ' Building is highly contam inated by the em pty hoppers which it tra n sp o rts. The lead concentration in s id e th e e le v a to r h a s a v e ra g e d 0. 03 m g-/ft.3 b a s e d on r e s u lts fro m the 2 4 -h r. sa m p le r in stalled A pril 29. The nitrogen purge sy stem fo r the hoppers should reduce this concentration. The lead level inside the elevator w ill be m oni to red to d eterm in e w hether the concentration is reduced signi ficantly after installation of the nitrogen purge system . .Tunnel - "C " Building tunnel is co ntam inated a t le a s t p a rtia lly by em pty hoppers which a re -stored at the north end. A 24-hr. sam p ler installed inside the south end of the tunnel averaged 0.016 m g /ft3 during a recent 9-day period w ith n o rth erly winds. "C " Building supply a ir averaged 0.005 m g /ft. 3 during the sam e period. T h ere is a strong possibility* that a p a rt of the Con tam ination of the building supply a ir which o ccu rs with n o rth erly w inds com es fro m the tunnel. This conclusion is supported by the fact that the lead concentration in building supply a ir has not dropped significantly since AB-9 began operation even though lead lo sses from the still exhaust have been m arkedly reduced. T h erefo re, the lead contam ination in the supply air apparently originates fro m som e so u rce other than the building exhaust system . The lead concentration in the tunnel and in the sup ply a ir w ill be m o n ito red to d e te rm in e w h eth er the c o n c e n tra tion is reduced after in stallatio n of the hopper purge system . "B " BUILDING 5th F loor 1 Alloy H oppers - Liquid has been observed, along with p articles of alloy, on the charging head slide plates and on the floor. o? A sam ple of this m a te ria l w as collected, ex tracted with toluene, IO a n d a n a ly z e d c h ro m a tig ra p h ic a lly . T r a c e q u a n titie s of T E L 03 o and TM L w ere found. T his TM L m ay have en tered the hoppers oO' w h e n t h e y w e r e i n T M L s e r v i c e i n " C " B u i l d i n g . If t h i s i s the case, nitrogen purging the hoppers in "C " Building could red u ce the contam ination on th e' 5th floor of "B " Building. - C om m unication fro m 4th F lo o r - A portion of the supply a ir to . th e 4th flo o r \#as blocked off as w as done in "C " Building in  ' - 6- The p re lim in a ry indication is that this did not reduce the lead concentration on the 5th floor. The contam ination p attern on th e 4 th and 5th flo o rs is show n in F ig u r e 2, " 'B ' B uilding Lead C ontam ination," F lo o r 1. P lu g g e d D ro p L e g s - P lu g g e d d r o p l e g s a r e th e b i g g e s t c a u s e of lo st charges and a re a m ajo r source of contam ination in "B" Building as they a re in "C" Building. . ' W ater-flushing should reduce the num ber of pluggages as should installation of teflon-coated drop legs. 2. D uraseal F a ilu re s - D u raseal failu res a re infrequent and a re th e re fo re little cause fo r concern. Only one fa ilu re o c c u rre d in A pril. ` 3rd Floor : .. 'm . .. V - i j j T he le a d c o n c e n tra tio n a v e r a g e s only 0. 003 m g /f t. 3 on t h e . 3 rd floor. T h erefo re, no investigation w as m ade th ere. Supply A ir . The lead concentration in the supply a ir to "B " Building ` n early alw ays analyzes low er than the supply a ir to "C " B uild ing. One reaso n for this a p p e a rs to be th at a p o rtio n of the le ad in '"B"! B uilding supply a i r is T M L, w hich is not efficiently absorbed by the sin g le -sc ru b b e r T E L sam p ler on the supply a ir to "B " Building. This TM L, th e re fo re , escap es detection. Supply a ir to "C" Building is sam p led by a d o u b le -sc ru b b e r TM L sam p ler which absorbs virtually all of the TM L p re se n t in the . air. .` . .' A double-scrubber TM L sam p ler w as installed alongside the existing sin g le -sc ru b b e r T E L sa m p le r on "B " Building supply . air. The lead concentration as m easu red by the TM L scru b b e r a v e ra g e s about 0. 001 m g /ft.3 h ig h e r th a n th a t m e a s u r e d by the TEL sam pler. This indicates that the lead concentration w ithin the building m ay be slightly h ig h er than that detected by the existing TEL sam p lers. Alloy A rea ..* * .- The lead concentration in the alloy a re a is norm ally fairly low. H ow ever, spot sa m p le s show th a t o rg an ic lead co n cen tr a t io n s a s h ig h a s 0. 076 m g /ft.3 o c c u r 'a t th e g r a p h ite a d d i . tion platform when an em pty hopper is positioned for graphite 0002522 - 7- h o p p ers w hile charging alloy to the au toclaves m ay red u ce this som e. H ow ever, the o p e ra to r who adds graphite to the hop - p ers should continue the cu rre n t p ractice of w earing a fre sh a ir m ask during the graphite addition step. ' '' ' - \- I R EC O M M EN D A TIO N S ^ The following recom m endations a re m ade for reducing the lead contam i nation h aza rd in the plant. I. The nitrogen purge sy stem for the alloy hoppers in "C" Building should be installed as soon as is practicable. 2. D e s ig n an d e s t i m a t e th e c o s t of a w a t e r - f l u s h s y s t e m f o r a l l 18 d r o p le g s in "C" Building. M eanw hile, continue the .w ater-flu sh te st cu rren tly in p ro g ress. v- 3. In s ta ll a te flo n -co ated d ro p leg in TM L s e rv ic e in "D" B uilding. T his drop leg has alread y been p u rch ased and received. If the unit p e r f o r m s s a t i s f a c t o r i l y , i n s t a l l t e f l o n - c o a t e d d r o p l e g s i n " B " , , MC n , a n d "D " B uildings as it b eco m es n e c e s s a ry to rep la ce existing units due to insufficient w all thickness which has been found on som e of the units. T eflon-coating adds only $100-125 to the cost of a new drop leg. ' '. 4. A ttem p t to im p ro v e the s e rv ic e fa c to r of D u ra se a ls in TM L se rv ic e . 5. T he com m unication betw een the 4th and 5th flo o rs in "C " Building should be fu rth er reduced. This m ay be accom plished by blanking th e a re a betw een the edges of the 5th floor and the building w all. The need fo r this cannot be d eterm in ed until the 5th flo o r lead concentration is m onitored after installation of the hopper purge ' . ' system . - ' ' 6. T he 4th flo o r of "C " Building w ill continue to be highly contam i nated even though the num ber of plugged drop legs and D u raseal fa ilu re s m ay be reduced. T his is due to the la rg e num ber of p o ten tial leak so u rc e s, the hig h volatility of TM L, the Cyclic n atu re . of the p ro cess, and contam inated m aintenance w ork such a s-re p la c e -' m ept of ruptured d iscs and re p a irs to slide valves, angle valves, and m ethyl chloride feed control valves. This contam ination can be contained and re s tric te d to the 4th floor w hich is not a p rim e operating area. H ow ever, if it is deem ed n e c e ssa ry to elim inate contam ination on the 4th flo o r it w ill be ' n e c e ss a ry to co n stru ct en c lo su re s around th e autoclaves. ' F ield te s ts with enclosures around C-13 and C -14 autoclaves indicate jy 0062523 th a t p ro p e rly designed e n c lo su re s a re v irtu ally 100% effective in containing contam ination w hich originates inside the enclosures. R. H. Jones RH J:jd K t 00025.24