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'! i \\ INDUSTRIAL HYGIENE FOUNDATION OF AMERICA, INC. Mellon Institute, 4400 Fifth Avenue \ Aril 14-15, 1966 OO BARBER v PITTSBURGH CORNING CGRP by asbestos litigation Morton Corn, Ph. D. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. Robert T. P. deTreville, M. D. Managing Director AA 024 AN ASSOCIATION or INDUSTRIES FOR THE ADVANCEMENT Or HEALTHFUL WORKINO CONDITIONS .T TABLE OF CONJ^NTsV BARBER v. PITTSBURGH CORNING CORP. V %ss ASBESTOS LITIGATION 1. Introduction II. Recommendations << / III. Threshold Limit Values o^Su es Measured in this Survey IV. Description of Sampling and ^balytical Methods V. Results and Discuss A. Plant No. 1: 'SLiss Block 1. Noise^l*tesu^;nents 2. HoocfAir Velocities 3. Decorative J'aint Spraying B. Plant NoNsi-*^brication of Foam Glass 1. /Mould ^Stripping 2. ; Mould ^Filling 3. Grinding Operations 4. Stay-Dry Pipe Cover C. Plant No. 6: Foamthane 1. Toluene-2,4-diisocyanate Concentrations in Air D. Plant No. 8: Unibestos Page 1 2 4 6 8 8 8 10 10 11 11 12 12 13 14 14 16 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT* BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA 025 J"BtT00O92lZJ. 5 \ 1. I. Introduction BARBER v. PITTSBURGH CORNING.CORP. ASBESTOS LITIGATION This survey was undertaken at the request of D)rrN^ee^. Grant, Medical Director, Pittsburgh Plate Glass Company. Dr. Gr^nT'lnitis.lly visited the Port Allegany plant during October 25-28, 1965 anSsSurtpiarized plant areas requiring further industrial hygiene assessment December 25, 1965 letter to Mr. Li. O. Griffith, Plant Manager. The surVy reported below concen trated on the evaluation of operations s4ngl^Nh)it by Dr. Grant, but also included additional operations. In tju^reppvx all aspects of environmental assessment investigated at the Post Allekany plant are discussed, with the exception of assessment of exposure by analysis of urine or blood samples obtained from workmen lead base paints. Dr. Grant will report on this phase of the survey Mr. Fred /an Dtfesen', Ceramics Engineer, Port Allegany plant, accompanied the ao^horduring the entire survey and also assisted with several measurements. Hi^j assistance is gratefully acknowledged. / THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CAN. 101' BE AUTHENTICAl ED BY PPG INDUSTRIES. INC. AA 026 J3B 0008739 J" 2. II. Recommendati ns A. Plant No. 1: Glass Block BARBER v. PITTSBURGH CORNING CORP ASBESTOS LITIGATION 1. Ear protective equipment should be fitted to operators-in the vicinity of the block forming circle, fire polishing line, block sealing hi^chinery, and the glass tank. Noise in these zones is excessive. 2. A permanent, rigid, hinged frontpiece shouloS^e installed on the front of the decorative paint spraying booth to replace the presently us d makeshift, cardboard frontpiece. q- \ 3. .A stringent personal hygiene program should be instituted for operators in the paint spray booth to enattve tm^ipaint on hands, fingers, etc. is not ingested. v\ J / B. Plant No. 2: Fabricationo^Joam Glass 1. Louvers on unpiv hoods above the mould filling operator should be adjustwSas oqscribed in this report and then locked in position. In this manner, dust from the mould can be prevented from entering the face^zone of the operator. Aj 2. Ear protection equipment should be furnished to the mould filling operator, who is exposed to brief, but regularly spaced sound level peaks f 106 db and base levels of 98 db. 3. Two overhead 8" diameter air ducts at line 1 mould filling position should be realigned as described in this report. 4. Ear protection equipment should be furnished to band saw and grinder operators. THIS DOCUMENT WAS NOT A RECORD OF UCf n-sA A fi97 ppG INDUSTRIES, INC. DID NOT COME FROM FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC I BB 000873 9*7 3. 5. The use of compressed air to clean clothes and work surfaces at the grinding operation site should be discontinued and a suction source should be substituted. 6. The exhaust line to the knockout bench should he repaii 7. Exhaust ventilation should be installed at the sta^/dry pipe covering operation where asphalt fumes are genera^^^^^^^ge quantities. C. Plant No. 6: Foamthane 1. Toluene-2,4-diisocyanate concen^at^ms^in air did not exceed th recommended ceiling value. Howeve^T" tftfe amount of TDI in the air f this plant can be greatly reduced byerfce^iny a permanent, three-sid d enclosure for the bun cutting operation., A^resent, a tagged, plastic J\7 curtain is being used for this purpbqe.^s*. D. Plant No. 8: Unibestos_ ^ 1. Asbestos dust ini the vicinity of the feeder operator was excessive when measured by stanjWrd te&miques. The feeder operator should wear (s respiratory protective equipment at all times. 2. To reduce airborne dust, a general tightening up of "houseke ping" practices should be instituted in this plant. Several specific suggestions are included in tide report. BARBER V. PITTSBURGH CORNING CORPASBESTOS LITIGATION AA 028 THIS. DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. J BB 0003740^1 4. 111. Threshold Limit Values of Substances Measured in Thliiss'sih^y Vt~-. "The threshold limit values refer to airborne coincentratKions of sub- .\ \ stances and represent conditions under which it is j&elievb^that nearly all workers may be repeatedly exposed, day after dl >ut adverse effect. B cause of wide variation in individual susceptibility, exposure of an occasional individual at or even below the threshold luniytnay not prevent discomfort, aggravation of a pre-existing conditioiy^ojrr^'^occuilpattii'ional illness. "Threshold limits shouild be jnisseelklhjsas ggxu. ides in the control of health hazards and should not be regarded as fine lines Between safe and dangerous concentrations." Threshold values for alKsubbt^nces measured in this survey are presented in Table 1. \ ,.o BARBER v. PITTSBURGH CORNING CORP. ASBESTOS LITIGATION THIS. DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA 029 Extracted from the Preface, Threshold Limit Values for 1965. American C nference of Governmental Hygienists, 1014 Broadway, Cincinnati 2, Ohio. \1 5. BARBER v. PITTSBURGH CORNING CORP ASBESTOS LITIGATION Table 1 V~ Threshold Limit Values For Substances Measured IxKThiV Survey- Substance ppm* mg/pi3**SSvMFPCF*** Asbestos (less than 1% crystallix ) 5 Lead Toluene-2, 4-diisocyanate )o/gp (Ceiling \^bljue)S. Broad-band (600-4800 cps) Noise St*** See Industrial Nois^Maihual, 2nd Ed. American Industrial Hygiene Association, 1412^ Prevost, Detroit, Michigan, 1966, Ch. 7. *** Millions of Pajrrtcles*'Pr Cubic Foot. ** Approximate milligrams of particulate per cubic meter of air. * PartB of vapor or gas per million parts of air by volume at 25* C and 'e: . 760 mmHg pressure. + Based on values adopted in 1965 by the American Conference of Governmental Industrial Hygienists. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA 030 ---iL00087i*2 7 BARBER v. PITTSBURGH CORNING CORP ASBESTOS LITIGATION *' IV. Description f Sampling and Analytical Methods The air sampling and measurement technique s used to assseess the environment during this study are described below. \/ Asbestos Dust A midget impinger containing 10 ml. of dMxuneraneed, distilled water was used to collect dust in air sampled at 0. 1 cfxhs^for ten minutes. Samples were agitated prior to withdrawing drops of suspension for microscopic exami- / nation in a Dunn Cell. Particles less thah^teiymicrons in projected area diameter "3/ were counted by viewing the sample witlTaiT'objective lens of 0. 65 N. A. (10 X) and a 15 X Ocular. Approximately ^OO^Oj^articles were counted in two different sample withdrawals. Tb^ countihg standard deviation was estimat d to be (N),*^where N is the totaI>*nunts<or the sample. A blank count was made n the distilled water. Dust concentration in the air, expressed as millions of particles per cubic foot (y(ppcfj\ was calculated from the sample volume, liquid collection reservoir, and and blank dust counts. The techniques used adhered to United States Public Health Service and Asbestos industry recom mended procedures. THIS DOCUMENT WAS NOT A RECORD OF Lead ' PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. Lead in air as particulates from paint spraying was sampled at 27 cfm by using an electrostatic precipitator. * An HA Millipore filter paper was also us d. Total particulate weight was determined by direct weighing of samples on a microbalance (+ 0.01 mg). Lead was determined by assuming the airborne material lead content to be that of the bulk paint (45-51% by weight). "Method f r Determining Asbestos. Dust Concentration. " Asb stos Textil Institute, Pompton Lakes, NevHjfer8eyUJP64. ______ Del Electronics Corporation, Mt. Vernon, New York. "j BB 000S74j__ \' \ 7. Toluene-2,4-diisocyanate A Unico* TDI Analysis in Air Kit was used. Aiirr'l^dra^n at 0.1 cfm through 10 ml. of absorber solution in a midget impbger^**'<rhe absorber solu. tion is analyzed in the field by colorimetric mathochs**\nd the resultant color is compared to a set of permanent color standards. Sound Intensity 'fg* A General Radio Company****4^^oouuii^pdl leWl mm eter. Type 1551 C, with ceramic microphone was used. ATTJheashirements were made on the instrument C-scale. The instrumesnnt waass^spyac!alHjratfedd in the anechoic chamber at the Graduate School of Public Health , Umvensit^of Pittsburgh. OO THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. #** West Concord, Massachusetts 01781. *| BB 0008744 Jj ---- Marcali, K.: "Microdetermination of TDI in the Atmosphere." Anal. Chem. 29, 552 (1957). * Union Industrial Equipment Company', 150 Cove Str et, Fall River, Mass. AA 032 8. V. Results and Discussion A. Plant No. 2: Glass Block Production 1. Noise Measurements Table 2 is a summary of results of sound intMenissiityymeeaassurements per formed in the vicinity of block forming and sprayum&eooppeePrXations. The results indicate that noise levels are very high and are bfeeyyoond t1 he threshold of damage risk, even when the polishing operation is Olffj^^. A S?rriingent criterion for sound 4/Tintensity is 85 db when sound is measure^on i. broad band basis (C-scale), as it was in this survey. An industry-wijiCTty^el 95 db, which is less stringent. The levels measured in the vicinity^oilf^'Valps-sss/ybblock operations exceeded even the less stringent criterion. Therefore- e2a protection must be furnished to operators in the Glass Block plant if thes'jJa^sitSLliitty of hearing damage is to be eliminated. At present the risk is grea ^ in the vicinity of block forming. G BARBER v. PITTSBURGH CORNING CORP ASBESTOS LITIGATION THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES. INC. 033 OQ 08 745~J Sample' Number BARBER V. PITTSBURGH CORNINg-CORP Table 2 ASBESTOS LITIGATION Summary of Sound Levels in the Vicinity of Select d Glass Block Plant Operations*.!. _______________________________________ V N77, . Location of Measurement ound Intensity, Decibels 1 Two feet from Forming Circle on linfe between Operator Room and polishings$tage (Polishing Operation OFF) 99 Same as (1), but Cooling Air Polishing Gas ON ^ ' . 103-105 3 Between lines 3 and 4 (Polisfi&fflOniferation OFF) 100 /^\V 4 Same as (3), but Coolijrc Air ON and Flame Polishing Gas ON / 102 Midway between N^. 3,amS4 lines near Forming Circle (Fb^yhing Operation OFF) 101 Same as (5), but Comjng Air and Flame Polishing Ga"<QN^ 102-103 ApproxingiCtelyXft from Operator near No. 3 li 8 Adjo^fing belt exit. No. 3 line 104 103 9 NeaVplass'Tank wall (background) 98 '10 Between lines 2 and 3 at Sealing Operation, at Operator's side 99 11 Entry to storage room at end of belt No. 4 near Sealing Area (Polishing Operation OFF) 98 12 Vinyl Spraying of Block Edges 2 feet from No. 3 line operation, next to operator 92 _Lj^0003746~| All measurements made on April 14, 1966 between 8:00 and 8:30 a.m. iDry bulb temperature * 88 *F.; Wet bulb temperature * 77*F.; Relative humidity =61%. TOJ THIS DOCUMENT WAS^T^ REOTRD^ 034 CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. Barber v. Pittsburgh corning corp. ASBESTOS LITIGATION 10. 2. Hood Air Velocities, Vinyl Edge Spraying Air velocities in the No. 3 line operation varied from 150 to 1,000 fpm from side entry to rear hood entry, indicating satisfactory ventilation control f vapors in this operation. Large particles cannot be'exhaj^ed and protection of the eyes was accomplished by the use of safety go^Ws. This operation does not require any modification to afford further oner^to^Jp^otection. 3. Decorative Paint Spraying- ........ Air velocities at the makeshift hoodfraifitinfcce (cardboard) were measured and air samples for particulates in aS* were obtained. The men had fabricated a 13" x 18" cut-out in a flat sectiqnV/4f cWCakardUUbUo6a41rdU uUsBeCdU tolU cLUoVvCeTr tLhUeC hood face. The cardboard did a goojfjob oAcontrol: air velocities at the open ing were 500-600 fpm. A rigid hingfe^^dotST faceplate, rather than the cardboard tl^h^sp now in use, should be attached t&^h/ spray booth. Particulate concentration msjhe breathing zone of the operator, based on a Millipore filter sample an&t^n electrostatic precipitator sample, was 0.3 - 0.4 mg/m^. The enamel ujsed contained 45 - 51 % lead oxide so that the lead in the air was notjp of the threshold limit value of 0.2 mg/m^. It appeared .to me that a more serious problem in this operation is the extensive paint contamination on hands and clothing which results from cleaning spray guns (which plug every 4-5 blocks) and extending hands into the box. Without a very rigid personal hygiene program, the operator could easily ingest a large quantity of lead picked up by contamination. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA 035 7"bB 0008747Ji B. Plant No. 2: Fabrication of Foam Glass BARBER v. hiTSBURGH CORhi^u 1. Mould Stripping ASBESTOS LITIGATION 11, < The mould stripping operation has been a source of minor eye injuries. The flow of air from overhead hoods downward over^v^ope^itor appeared to re-entrain dust upward from the mould to the operfRoir^-Aye. It is believed that the reason for variations in severity of incMgnceW these injuries at different stations is related to the adjustmensof^ir louvers on the overhead hoods. Thusf at Station No. 1 air velocities \^e^e 4560 - 6000 fpm at the face of the slotted 3 ft. x 1 l/Z ft. hood. At Stktimts 2-4, air velocities at the face were 1500 -4000 fpm. No. 2 Stataqr/hadf lowest hood face air velocities. The reason for these variations isrthat use resistances of the ventilation lines are varied by the men as they attj^swhir louvers. The remedy to this situation /\ is to lock the louvers in posi^ony&fter adjustment by engineering personnel. At Station 1 the louverbsjwere adjusted in a series of test positions to see if air could be directeUsboth downward at the operator's back and forward towards the oven anl<q over me roller table. These cursory studies were made in the presence Dusen. It appeared that by proper adjustment of louvers, with s^rnc setjperpendicular to the floor and some at approximately 45* to the floor, the air could be effectively used to keep dust from the opera tor's face. - BB 0003748 | The only alternative I can suggest to the above simple solution, is the installation of suction sources below the knockout table. I believe the present situation can be remedied by simple louver adjustment without recourse t AA 036 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BARBER v. PITTSBURGH CORNING CORP. ASBESTOS LITIGATION 12. major engineering of the facility. If simple louver adjustment and redirection of air results in too little air reaching the operator's back, there is sufficient air at each hood to extend the hood to face dimension^ of 2 l/2 ft. x 3 ft. 2. Mould Filling Sound intensity levels at the filling operation ^wer^ yo - 106 db, which are excessive. The 106 db level was intermittent, ocfb^ring^only during the filling /^ cycle (approximately 1 second), but ear protecno^qhotouuld be utilized by the operator. Two overhead 8" diameter air ducts af'iijje 1 filling position are poorly located. Air is directed at the flo&x/witfe the resulting upward flow of dust. The jet should be lowered asm aligned parallel to the floor. 3. Grinding Operations 'S- /\ Hood air velocities at theuryfders for 5" block face and side cuts were greater than 1000 fpm,, indicatin^excellent control. An exhaust duct under the knockout bench at the grinds^ig site was not operative because of a connection break on the floor. This/is a p^or location for the duct. It should be relocated (overhead entry) or somLeeoonn>>lfio\uld be responsible for checking the connection in the present site.. '^^HHoowweevv^jrr,, dust was well under control at this location. Installation of exhaust cohtrol on the band saw would further improve the operation. Sound intensity level at the band saw was 92 db: at the grinder it was 94 db. In my opinion, continuous exposure to levels in excess of 85 db is an unnecessary risk. These men should wear a form of ear protector. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES. INC. DID NOT C0ME IT'S FILES AND CANNOT BE AUTHENTICATED AA f]07 by PPG INDUSTRIES, INC. 1 BB 0003749 J 1i \5 13. In this area the men used compressed air to "dust-off" surfaces and themselves. An air jet is an excellent dust disperser and housekeeping would N, be improved if an industrial vacuum cleaner, rather than an air jet, was used for this purpose. 4. Stay-Dry Pipe Cover V/ In this operation a synthetic asphalt, ftb^de^230, is rolled on the foam glass pipe sections. A condensed liq^Mtat^me rises from the hot, wet rollers and is often in the breathing zone of tfen^pperator. An air sample (Millipore filter) obtained at the breatiun^K^ne of the operator indicated a concentration of 5.1 mg/m^. Unforttaa^ftelyC the ingredients in Kendex 4230 could not be determined and it is^iot possible to assess the health hazard of this exposure. The fume from he'o^ayaattiion also impairs visibility in the shop. It is recommended thl^itt sii/dflee--slot suction ventilation be utilized at this site. The slot air velocity'vfrH^deferease to 10% of its value one diameter from the face so the tar ^Stfh^el^and exhaust slot must be in close proximity. The saturated/vapork from this operation will condense on any cold surface, including ansq&^tfst slot. Frequent cleaning of a hood exhausting asphalt fumes is ^the only way to ensure good performance . V) 5. Accoustlc Tile Spraying Mood face air velocities at this operation were 150 -250 fpro and control was satisfactory. BARBER v. PITTSBURGH CORNING CORP. ASBESTOS LITIGATION THIS DOCUMENT WAS NOT A RECORD OF me '^STRIES- INC- D'D NOT COME FROM AQO !LS F AND CANNOT BE AUTHENTICATED AAH (jj8 BY PPG INDUSTRIES, INC. bb 0008750 _j_ C. Plant No. 6: Foamthane MRBa^.C0SNWGC0RP. ASBESTOS UTIGAml 1. Toluene-2,4-diisocyanate (TDI) Concentrations in Air Table 3 is a summary of TDI concentrations based oh air sampling in this plant. All measured air concentrations ofxTDI were less than the ceiling value recommended by the American ConferenciTof'toa^ernmental Industrial Hygienists (0.02 ppm). The operation which requires furtWteT^&ii^rol is hot wire cutting. At present the men have erected a flexible^nlasti^curtain enclosure for the operation. This enclosure should In1 n I'igiil mu enclosing three sides of the /Swork bench from hood rim to floor/ Thisre commendation is based on measured air velocities at this site. Fivvee feet iSsun the ground, in front of the work bench, velocities were 50 -75 t4opmm, w}lich iss comparable to room air veloci ties. Seven feet from the gro^uSrSWrd^l^OioOo ffpj m velocities were found. These velocities are low and are^psxj^roaabhly due to air leakage into the plastic enclosure at ground level in the real Qfce work bench. oo THIS document WAS NOT A ..\,,nc-rniF_S. INC. DU ,r ATED AA 039 bB 0008751 \ 15. BARBER V. PITTSBURGH CORNING CORP Table 3 ASBESTOS LITIGATION Concentrations of Toluene-2,4-diisocyanate in Air, Plant No. 6* Sample 5 6 7 Location X TIJDJJ1 Concentration ppm X7 Breathing zone of operator <0.01 (foam formation) Breathing zone of opezhtorrSNjjBBun cutting at end of belt/v&*n sidfe) 0.01 Breathing zone of operator 2; Bun cutting (center oD^ji`koeurii jsfrBftiee ) <0.01 Breathing zon^ of oppeeirator; Hot wire cutting / 0.01 Breathing^one a operator; Band saw XJ Repeat Shaammppilfecs^r, wire cutting / /x Bacl^joynd sample <0.01 0.01 <0.01 * Sampling performed o: , 1966, 1:30 -3:00 p.m. THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S HLES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA 040 J7 SB 0008752 D. Plant No. 8; Unibestos BARBER v. PITTSBURGH CORNING CORP.*6' ASBESTOS LITIGATION Dust in this plant was sampled and assessed using the midget impinger * techniques which are still standard practice in the United States. It should be stressed that these techniques are undergoing transiticSn^and^pave much be be desired, but they have been used for many year^3lt& still the basis for recommended threshold limit values. Table 4 iVa summary of the results of three air samples obtained in the plant. The conb^ntration of dust in the breathing zone of the feeder is excessive. The feeder wore a respirator and this practice, if voluntary, should be cornfmlsdxy. X/ Concentrations of Asbestdbvin Air of Unibestos Plant* Sample 1 , # 2" 3 ^-- ------------------------------------------------------------ ^I*ocation s: `'Breathing zone of Sawyer (\^ r Breathing zone of Feeder background Dust in Vicinity of Feeding Operations MPPCF** 1.40.1 li.s^o.e 2.30.4 ** Millions of PartifcWs Per Cubic Foot * Sampling performed on April 14, 1966, 4:00 -5:30 p.m. TH1S DOCUMENT VMS NOT A RECORD^ Si "ScANNO? BE AUTHENTICATED AA 041 1 BB 0008753 | I 17. Housekeeping procedures in this plant should be greatly improved for they undoubtedly contribute to the airborne dust. Some of the observed pro cedures, which should be modified or discontinued, are listed below. 1. Shoveling scrap material from stora'gc^uy^to feed bins. 2. Feed bin conveyor belt returns (lSmes^ 1 !nd 2) are not enclosed and material drops to the floor, thus creatfaur du^t. 3. JLine 1 cyclone hopper at ent/ytei*|he conveyor belt leaks. 4. Material drops from the fan ejStvy^feed line conveyor belt to a 55 Gal. drum, dispersing dust as it fafts.^ Air velocities at the feed varied from 50 - 90 fpm in the Dll bin to 130 - 170 fpm in the a^rapbin. These velocities are too low for effective control of dust at this sitOs^/ Air velocities above Ahe cutting saw bed were 150 -200 fpm and appeared to be effectively'controlling generated dust. BARBER Y PITTSBURGH CORNING CGRP. ASBESTOS LITIGATION THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. AA '042 I BB 0008754 |