Document KRaaZrQ8o02Vp53n1q7yv6X3N

l;hCO Fill.:'. Avunuo Pittsburgh, ?.3, REPORT OF INDUSTRIAL HYGIENE SURVEY MALL FOR Pittsburgh Cornin,? Corporation Port Allegany* Pa.., September 26, '?h5 jUv ',iu Field V/ork Dys Laboratory '..ror!c By (and) Francis Ro Holden., Industrial Hygienist Edwin 0, Hyatt Industrial Hygienist P L.> ToobOj Moll, University of Pittsburgh December 6, 19lio Industrial Hygiene Foundation of America,;irj ;.v^f By: John PF, Mclfehon Managing Director Tfl' Industrial Hygiene Survey made for Pittsburgh Coming Corp., Port Allegany, ?a,,, September 26, 19b0o TA3IE OF CONTENTS Pages 4MNMM SUM...,......... ........................................ ................................... .................................... 1 I - FOAMjLAS plant........................................................................ ................ .. 2-$ Hold Pilling Operations............................ ...................................................... .. 2,3 Dust Concentration and Composition from told Filling -Table 1... 2 Spray Booth......... ................ .................. ....................................... .......... .. 3*U Dust Concentration in the Air at Spray Booth - Table 2.........0 3 FOAMQLAS Lehrs..................................................................................................... . k Dust Concentration at Take-off End of FOAtiGLAS Lehrs - Table 3... U Cutting aiid Packing FDA'-CLAS................................... ........................... .. 0 Dust Concentration in Cutting end Packing Room - Table It.'5 II - MAIN PLAIIT - BATCH HOUSE............... .................. .............. .................... .................. 0-7 Dust Concentrations in Air of Batch House - Table 0................. 6 Composition of Respirable Dust in Air of Batch House - Table 6...... 7 MAIN PLANT - GLASS*TANK..................................... ................................... ............ . 7 Dust Concentration in Air at the Olass Tank - Table 7............ .. 7- APPENDIX A T&TKOtf 'of"INVESTIGATION. . ............ Dust Count Samples........... .. Dust Counting............ .............. . Duat Composition Samples..,. The Separation of Dust Sizes 8-10 8 8 9,10 10 APPENDIX B H^aXtJTHASARDS IN CONTAINER GLASS MANUFACTURE................................................. .. Sand................ .............. ........................................................ ................................... .. Soda Ash............................................................ .............. ............ ......................... Feldspar................................ ................................. .................................................. .. Lime and Limestone........................................... ................ ........................... .............. . Salt Cake (Sodium Sulfate).............................................................................. .. Barytes (Barium Sulfate)........................................................ ............ .............. . ,, Borax................................................................... ............................................................... Cullet........... ................................... ................................................................................. Arsenic................... ................................ .. ................. .................................... ...... Selenium,....................... .......................... .................. ........................... -............ UiplS Sea Coal..................................................................... ............ ................. .................. Iron Sulfide,........................................................... .................................. Antimony............................................... ............................................................. Silicosis.,............... ............ ......................................................................................... total Poi3oning.............. ................................................. ......................... Dustiness Index of Sand.............. ............................................... 11-17 11,12 12 12 12 12 13 13 13,lU Hi 15 15 15 10,16 16 16,17 INDUSTRIAL HYGIENE SURVEY MADE FOR PITTSBURGH CORNING CORPORATION FCRT ALLEGANY, PA, SEPTEMBER 26, 19h$ A SUMMARY Operations in the FOAKGLAS plant and the main glass plant at Port Allegany, Pa0 were studied on September 26* 19h5 to identify the working con^ ditions that night be harmful to the health of workers,, The results of our Investigation show that there i3 no silicosis hazard in either plant. We do however call attention to the gross dust ex posure resulting at the spray booth in the FOAMGLAS plant when the dust collec tor is shaken, Oar data also add weight, to the need for more semi-automatic batch weighing equipment, No antimony detected in the air-borne dust from the FOAMGLAS batch. However,, a small amount of arsenic was present. General information on the toxicitios of batch ingredients and methods employed in this survey are presented in the appendices0 T" Industrial Hygiene Survey made for Pittsburgh Corning Corp0, Fort Allegany, Pa., September 26. i9b5. 2. ' I FOAMOLAS PLACT FOAM"LAS la manufactured from powdered glass and carbon with a trace of antimony. All of the silica is present as silicate and hence there Is nosilicosis hazard. Theoretically, there is a possibility of poisoning from the v. antimonyo This possibility wa3 appraised by chemical analysis of tha air-bome dust collected from the breathing zone of workmen,. Throughout the plant dust concentrations were measured by dust count. Theao latter results are a measure of the effectiveness of the plant ventilation equipment. Mold Filling Operations - At ths time of this investigation, on a temporary procedure, FOAM}LAS batch for one lehr vas being weighed and handled manually in a small hand scoop. Batch for two other lehrs, however, was v/eighed by semi-automatic equipment. The results from analysis of air samples are presented in Table 1 TABLE 1 - DUST CONCENTRATION AND COMPOSITION FROM MOLD FILLING Sample No. P.C.3 Date Tima 9/26 1:0GP 1:56: location and Operations Mgs. of Arsenic Per Day Sample was collected beside work- man weighing batch by hand. Much visible dust. This is a temporary operation. 0.7^^ Du3t Count M.P.C.F*# : h3 P.C.10 9/26 2:L5P 2*55P Sample was collected in the breath- -- ing zona of workman operating the serai-automstio mold filling machine0 6.3 u r. nf' nsrWnlfln tiot< r>mvlr ni' n-lw (1) Antimony was rot detected by Gutaoit tost. Controlu showed characteristic anti mony reaction. Arsenic was found to bo present, however, in the amount indi cated In tbs table. Industrial Hygiene Survey raado for Pittsburgh Corning Coro.., Port Allegany, Pa0, September 26, 19U5. J 3 It is of considerable intoreat that, whereas no antimony wa3 detected in Sample P.C.3, arsenic was present to the extent of 0.7 milligrams per 10_cubic \ meters of air, This amount is slightly below the maximum allowable concentration . recoranended by the American Standards Association (1,0 mg,, per 10 cubic meters). Weighing of the FOAM}LAS batch by hand va3 nearly 3even times as dusty as was the semi-automatic equipment,. The installation of the latter equipment for all batch weighing is desirable,, The dust exposure howevor is a nuisance rather than a health hazardo Spray Booth The FOAMCLAS batch is placed in metallic molds previously sprayed with a clay-water dispersion to prevent sticking. The molds are cleaned by an air jet and then sprayed in a spray bootho The dust exposure of the spray operator is -resented in Table 20 TABLE 2 - DUST CONCENTRATION IN THE Afe AT 5PRAY BOOTH San.me Ko. P.C.6 Date 9/26 Tine lxlilP liLP location and Operations Sample was collected in the breathing zone of workman cleaning molds with air blast and applying olay by spraygun to clean molds. Dust collector was shaken during part of this tost* hence no exhaust ventilation. Dust Count MoP.C.F. 260 Industrial Hygiene Survey r.ade for Pittsburgh Corning Corp5 Fort Allegany, Pa,,, September 26, 19ls5, li. During the sampling period the dust collector for the spray booth was j shaken which necessitated turning off the fan and thus shutting off the spray bootl ventilation, Tho resulting dust exposure during the ten rnimta testing period ..was 260 M.PoC.Fo (milliora of particles per cubic foot of air), Evan though the free silica content of the clay is low, such an exposure is excessiveo We recommend that all spraying be stopped whenever the collector is shaken, Obser vation indicated that spray removal in the txsoth is effective when the ventilating system is operating, POATOLAS Lehrs Air samples were collected by the midget impinger at the feed and take off ends of the lehrs. The results appear in Table 3o I TABLE 3 - DIJST CCtfJENTRATION AT TAKE-OFF e:;q of foamolas lehrs Sample Hoo r,c.u Date 9/26 Time I:13P If23? location and Operations Sample was collected beside workmen removing FOAKOLAS blocks from lehrs0 Dust Count MoPnC.F. 3c3 p,Co5 9/26 1:2?P 1*3 ?P Sample was collected beside workmen re moving FOANOLAS from molds and placing it in lehrs. 2,S Tho dust concentrations in the breathing zone of workmen represent satisfactory working conditions. . rk vTM ----- Industrial Hygiene Survey mde for Pittsburgh Corning Corp^ , Port Allegany, Pa., September 26, 19hi?o 5o Cutting and Packing FOAMSLAS One air sample was collected be3J.de workmen who operate the power saws0 Table ii contains the data. TABLE li - DUST COJEENTRATION IN CUTTING AND PAGKIM} FOAMBLAS Sample No. PoC.l Data Time 9/26 11j25A 11s3?A Location and Operations Sample was collected in breathing sono of workmen operating saws. Exhaust ventilation on 3aws is excellent. Some visible dust from handling FOAt'-DLAS blocks. Dust Count MoPcC.fL ' 6.3 The ventilation provided for.the power 3awo is excellent. Some dust is produced from handling the FOAHGLAS blocks but, as shown in Sample P.C.l, it is net significant. II - MAIN PLANT - BATCH HOUSE The principal duct hazard in glass batch houses is in sand handling. At Port Allegany dry sand is purchased in hopper cars which are unloaded into a hopper to an elevator. The sand is conveyed into an enclosed bin without exposure of -workmen to dust. st Industrial Hygiene Survey reads for Pittsburgh Cor ring Corp,, Port Allegany, Pa,, September 26, 19h?, 6 The batch house weighing operations are totally enclosed with the exception of the addition of minor batch ingredients. Materials feed from the bins into weigh hoppers and then are dropped onto a belt which conveys them to "the mixer. Mixed batch is' loaded into a hopper car in Biaall room which is separate from tho batch mixing room. Two midget ircpinger samples and one I-H-F composition sample were collected in the main batch house, Ths results appear in Tables f> and 6, TABES $ - DUST CONCENTRATIONS IN AIR OF PATCH HOUSE Sample No, P.C,,7 Date 9/26 Tims 2:02P 2:12P location and Onerations Sample was collected while walking around the batch house. The batch handling system is totally enclosed except for the addition of minor batch ingredients. Dust Count MoPcC.F,1 5*3 PoC,8 9/26 2:liiP 2:2iiP Sample was collected while vra'lking around ths batch houao0 Ths batch Ivandling system is totally enclosed except for the addition of minor batch ingredients. 3o3 "industrial Hygiene Survey made for Pittsburgh Corning Corp,,3 Port Allegany, Pa,, September 26, ?.9h$a 7o TABLE 6 - COMPOSITION OF RESPIRABLE DUST iN hik OF BATCH MOUSE Sample No, P.C2 Date Tina 9/26 12j50P 2t25P Location and Operations Sample was collected from breathing sene near olevator to mixer. Brea Silica in Respirable Dust (Portion 5 microns | and less in Size) 1% The average dust concentration was U,,6 MoPoC.F., of which.only 1% was found to be free silica. The exposure to frea silica i3 therefore about 0,,3 M.PC.F. The maximum allowable concentration of Bilica dust for continuous ex posure is 5 M.P.C.F.t the safety factor is therefore more than 15 to one. MAIN PUNT GLASS TANK One air sample was collected at the feed end of the glass tank. The result is given in Table 7 TAELS 7 - LUST COHCEHTRATIOH IM AIR AT THE GLASS TANK Semple Ilo. PoG,9 Da to 9/26 Time 2:30P 2;iiOP Location and Operations Sample was collected while walking around platform at feed end of tank, Batch feed ia dust free0 Duat Count MoP.C.Pi. 1,0 The duct concentration in far below anything significant to health. The batch feed saathariam is tha finest arrangement for controlling dust that we have seen. Industrial Hygiene Surrey made for Pittsburgh Corning Corps Port Allegany, Pa,,# September 26, 19U5* 8 APPENDIX A METHOD OF INVESTIGATION Dust Count Samples All of tha samples-for counting purposes were obtained with the aiiiget impinger* Where workmen were stationed at one position the sample was collected in the breathing zone within a distance of a few inches of the worker*s nose. In many cases it was necessary to follow employees about a department in order to obtain a sample representing their average exposure* This was particularly true in the batch houses while appraising the exposure of botch gatherers*. Where no obvious source of dust was present a general air sample was collected to provide data on the exposure of groups of workman,. This type of sample occurred in tha warerooms and machine rooms` All of the dust count samples were collected in normal propyl alcohol with tha usual time period being 10 minutes,. Dust Counting All samples were counted in accord with accepted standard procedure* The dust suspension in tha Inplnger tubes was deposited in a standard Sedgwick Rafter Cell, where it was allowed to settle for exactly 20 minutes, then n, particlos at or near the bottom, smaller than $ microns, were counted at 5 widely spaced locations on the cell* This was repeated with another cell similarly pre pared and all 10 counts avoraged, corrected for the blank count, and the resulJ computed on this corrected avorage count* The blank counts were made at .suitable intervals Q `Industrial Hygiene Survey inada for Pittsburgh Coming Corp., Port Allegany, Pa0, September 26, 19hi?* Du3t Conmcsiticn Saaolca Dust counting alone doe3 not permit appraisal of the silicosis hazrrrd since it indicates only the number of visible dust particlen -without regard to their composition,, That is, quartz dust which produces silicosis cannot be dis tinguished in th3 dust counting process from any harmless du3t, and therefore' auxiliary dust samples of greater 3ize must be obtained for free silica analysis In addition to samples for dust counting, therefore, separate air-borne eamples were obtained for determination of dust conpositicn for free silica. These samples wore collected by moans of the I-H-F Dust Sampler This device employs a portable exhaust fan with a capacity more than a hundred times that of the midget impirger pump The air is drawn tlirough a filter composed of a felted layer of salicylic acid crystals, about 0.2 inches in thickness The filter hla an area of approximately ono square foot Du3t collected by the I-K-F Dust Sampler is removed from the salicylic acid by treatment with alcohol. The salicylic acid dissolves leaving tha dust particles The solution is filtered and the dust washed free from alcohol soluble dements Following separation by sedimentation the fractions are analyzed by tha X-ray diffraction method - Experience has shown that chemical methods for the determination of free silica in finely divided dust samples is unreliable An alternative method based on the petrographic microscope is also unsatisfactory because of tho impossibility of correct identification of different ndnaralo with the small particles eize present. We, therefore,, employed X-ray diffraction analysis Industrial Hygiene Survey made for Pittsburgh Corning Corp., Port Allegany, Pa, September 26, 1 10 o for the deter nir.i cion of free silica,. These analyses were performed for us by the Saranac laboratory, Saranac Laica, New York., under the direction of Dr. ii Uo Gardner,, The Separation of Hast Sires iu i .'i i ' ~ It 1b known that only dust less than $ microns in diameter is of significance tilth regard to silicosis# Therefore samples for coirposition analysis, which contain particles as large as iiO or 0 microns, should bo treated to rJmove tteae and other particles of non-respirable sicca and ohis vie do by means of sedimentation. The separation is made at the ? micron size, and X-ray analyses performed for the finer fraction.. Occasionally the larger noir-respirable fraition. is analyzed. A proper sampling ox' glass batch without attention to particle size would show about 70% silica by weight,, it in known, however, that the major portion of the 3ilica is of large particle sice and frequent unalyse3 of air borne dust from glass batch show only from ore to five percent free silica0 The procedure for the separation Is 3 follows; A sample is suspended in alcohol to a depth of 33 centime tore ar.d uiicn a uniform suspension ha9 been obtained a settling period of bO ninutea is allowed. The supomatant liquid, together with all particles in suspension, is then drawn off and fresh alcohol added to the sediment sufficient to again make the total depth 3.3 centimatersc The neif suspension is agitated and again settled for UO minutes. This is repeited 10 to 15 tines, until the supernatant liquid is observed to contain an insignificant quantity of fine particles. ` n. i- j. i V -i Industrial Hygiene Survey made for Pittsburgh Corning Corp0, Port Allegany, ?a, September 26, 19l5,, APPSMEX E HEALTH HAZARDS IN CONTAINER GLASS MANUFACTURE Container glass made ba manufactured from tho following ingredients, 'sand, soda ash, dolomite, feldspar, slag, lime or limestone, salt cake, and c| barytes, and borax. Minor batch ingredients for decolonisation or for the pro, duction of color include arsenic, selenium, sea coal, iron sulfide and antimony, A discussion of the toxicity of these ingredients follows: Sand Glass sand consists principally of tlio chemical compound, silicon dioxide (SiOj), It3 most common firm is crystalline quartZo Quartz, itself may be converted to tridymite and cristobalite when heated to high temperatures, Silicosis is one of the two characteristic lung diseases resulting from exposure to dust. It is characterized anatomically by generalized fibrotic changes and increased susceptibility to tuberculosis., Silico3is is caused by free silica either in the form of quarts, tridynite or criatobalite. It is gen erally recognized that combined silica (the silicates) with tho exception of asbestos, does not produce disabling lung diseases,. Silicosis may arise from prolonged breathing of atmospheres containing finely divided free silica,, Ths free silica is only significant in the particlL ranges from one to five microns or less, and modern thought pays attention to the presence of those particles in the air which are lees than five microns'^in oisQc Studios of the 3ilico3is hazard in granite cutting, in the minir^ of cntfuracite coal and other industries, have furnished the basis for establishing Industrial Hygierja Survey made fcr Pittsburgh Corning Corp., Fort Allegany, Fa., September 26, lS'h5o 12, a bench mark in terns of chist counts for maximum continuous exposure to free silica. Authorities believe that disabling silicosis will very seldom if ever occur if.the exposure is below 5 million particlee of silica dust, les3 than 5 ` -microns in size, per cubic foot of air* Soda Ash Excessive exposure to soda ash dust is irritating to tha renpiratoijy tract and may produce dermatitis, this action being worse during warm weather* Studies of the health of workers in plants manufacturing this product have shown that as much as 30 years continuous exposure has not resulted in any systemic r disease* Feldspar Feldspar is a gonaric term for a number of complex aluminum silicates containing sodium, calcium, potassium, or barium* These minerals may contain some free- silica but in general the amount is loss than Materials containing 1ob3 than froe silica are considered as nuisance dust and it is not belioved that exposure to them will result in disabling disease,. Lime and Limestone Those alkaline' ingredients of glass batch aro also nuisance dust3* Excessive exposure to them during hot weather frequently results in dermatitis but no general systemic effects occur. They do not produce any characteristic lung disease. Salt Cako (Sodium Sulfate) Sodium sulfate dust is not.,toxic. Excessive concentrations may causa a nuisance Industrial Eygieno Survey made for Pittsburgh Corning Corp., Port Allegany, Pa., September 26, 193. ^sSiS* Ssrytea (Barium Sulfate) Barium sulfate is not known to cause any characteristic disease. The Italians described a lung disease which they call barytosis. Radiologists, such os Pendergrass, attribute the effect described by the Italians to the fact that barium sulfate is radiopaque. They beliove that the inhalation of finely divided barium sulfate will produce a characteristic roentgenogram but that there will not be disability associated with this condition. In this respect it is similar to the lung condition described by Sander where the lungs of electric welders often exhibit an X-ray appearance practically identical with silicosiso In general, therefore, we may conclude that barium sulfate will not cause occupational disease but that it nay produce a characteristic X-ray finding which could conceivably complicate the interpretation of the roentgenogram of workers also exposed to free silica. The implications of this are especially important to glass plants and i3 the basis for our recommendation to control this dust where it occurso Borax From the industrial viowpoint borax i3 not toxic. Schwartz reports that it is known to cause dermatitis and therefore oxpo3ure to this compound should be kept within moderato limitB, particularly in hot weather. Cullot Although glass consists principally of silica, that material is present in a combined fora ao silicates.. Numerous X-ray diffraction analyses of Samples oi air borne glass dust have aJiown that thoro is no free silica present. 'Ssfi* rare flrgrwTw Industrial Hygiene Survey maao for Pittsburgh Corning Corpos Port Allegany^ Pa.3 September 26, 19l<5 Hi. Daring the early days of the studies of industrial exposures to dust it ots believed that lung damage was caused by the nechanical action of sharp dust particles. Ibis v.ais thought to be true even in tho ease of fz*ee silica. -- Investigation of v.-orters who had breathed large quantities of carborundum and diamond dust, however, disclosed that thoir lungn had not been damaged. It is now known that fbro3i and irritation of lung tissue is a chemical action independent from mechanical irritation with tho possible excoption of exposure to asbestos. Arsenic Historically0 poisoning from arsonic and its compounds has been recog nized since ancient times. In arsenic poisoning there is an extreme gastro-enterifcia9 with particular damage to the nervous system, and fatty degeneration of the cells in tho glands and muscles. There may clco bo direct paralysis of the heart. The American Standards Association has recommended that thu jrauduana allowable concentration to arsenic and its compounds should bs 1-1/2 milligrams of arsenic per 10 cubic meters of air. Arsonic ray also cause perforation of the as well as severe dermatitis. septum tal-finlun Solonium and its compounds are cumulative poisons. Excubaivo exposure mil produce gaatro-intastinal disturbances, narvouune33, pallor and a garlic odor in tho breath and perspiration. Studios of tho acute toxicity of polonium compounds chow that tho pewdorsd metal is not very toxic when ingested. Cuapek and V.'cil, report that k grams of tho powdered metal given to clogs by mouth produced no toxic effects as the metal was not absorbed. On tho contrary as little as U I HU'CWcu.'i i!'.' --< Industrial Hygiene Survey made for Pittsburgh Corning Carp : port Allegany, Pa,, September 26} l?h5o l5 y.:i illgrans of sodium selenite or sclenats par kilogram of body woiglvt is-usually fatal within a. few minutes, No authority has suggested a maximum allowable con centration for continuous exposure to selenium and its compoundsTM It is doubtful that selenium is any r.oro toxic than lead, cadmium, morcury and other cumulative metallic poisonB end we therefore recommend that concentrations be maintained below one milligram per 10 cubic meters of air,., Sea Coal This material ia finely diridod bituminous coal. Since thi3 material contains much less than IX free silica its handling cannot cause a silicosis hazard, The coal dust itself does not cause characteristic lung disease;, Iron Sulfide This compound ia relatively non-toxic and its inhalation in moderate amounts is not considered harmful. Antimony The action of antimony in thu body rosemblos that of arsenic, differing chief?y in greater local irrituticn and more difficult absorption. The metal ia commonly associated with lead or arsenic and no clear cut picture of industrial antimony poisoning is available. No maximum allowable concentration lias been established so it is common practice to assume a limit similar to lead (1,5 mgs, pur 10 v'ubic motors e.f air). Silicoul Industrial Hygiene Survey made for Pittsburgh Corning Corp*, Port Allegany, Pa*, September 26, 19ii5* 16* confined mainly to the handling of sand aa a raw material* Ivhen it is combined with the other batch ingredients the silicosis exposure is practically ail* _ Ketal Poisoning Frequently it 3 necessary to add certain metals and their compounds to glass either to prevent undesired color or to produce color* Metals such as lead may also be added whan special glass characteristics are needed* These minor batch Ingredients such os arsenic and selenium are added in small amounts and numerous investigations have shown that careful handling is common and does not result in a health hazard* However, wo have encountered excessive dust when these metals are gathered and weighed because of careless handling by tho particular workman. In these latter instances methods of control by exhaust ventilation aro recommended on the basis that it is frequently impractical to convert a careless workman into a careful one* Lead as a constituent of glass batch is generally a major batch ingre dient and when used normally requires exhaust ventilation of portions of the process* Dustiness Index of fand The dustiness index of glass sand is a measure of the quantity of respirable dust contained in a unit weight end theroforc provides a basis for comparing various sands respecting their potentialities for producing atmospheric dust when handled, as by shoveling,, Tho analysis consists of sieving ICO grama of the material through a 320 raeah screen* The amount passing through tho screen i3 weighed and a known portion of it dispersod In alcohol and counted using the microscope* This data . industrial Hygiano Survey nude for Pittsburgh Corning Corpc a Port Allegany, Pa.. September 26, 19hC<, 17 o provides an estimate of the lailliono of particles of respirable dust present in 100 grams of the parent material0 Variations in the dustiness index from 30 to 600 are common,, It is obvious that a material with a low dustiness index ia desirable and that its use will assist materially in the prevention of silicosis,. We are currently collecting data to provide a quantitative correlation between dustiness index and the actual dust concentrations near certain specific operations, e.g,, freight car unloading by shovel and wheelbarrow, W INDUSTRIAL HYGIENE FOUNEATIOH OF AMERICA, IHC. UhOO Fifth Avomie Pittsburgh 13, Pa0 RECCSiMEHDATIONS OM DUST CONTROL Prepared for PITTSBURGH CORNING CORPORATION Port Allegany,, Pa,, February 13 ,, XU 19kb Si's W. G. Lo h'amoon Head industrial Health Engineer March 1, 19U6 Inductriol Hygion.3 Foundation of America, Inn0: Byi John P0 McMahon "Hahigihg Uirectar R3C0KHENDA.TI0KS ON DUST CONTROL PREPARED FOPv PITTSBURGH CORNING CORPORATION PORT ALLEGANY, PA. FEBRUARY 13, 11*, 1916 SUKMARY Biia report deals with a vieit to the plant on February 13 and lit, I9I46, in company with Dr0 Holden and nuoplaiaonta Mo report on visit made on September 26 ISaSe Various recommendations aro offered for improved control of nuisance duota in the Fcnjnglas planto . Redonaosndatiors aa dust control prepared for Pittsburgh Corning Corporation, Port Allegany, Pennsylvania, February 13, lit, 19U6. 2 c'oulet mmiG. milling amp mixing While this is inherently a du3ty process, tho system succeeds in con fining generated dust within enclosures (elevators, bins, etc.) without the neces sity for an exhaust system. It is very unusual in these respects and the designers arc to bo complimented. Dust does oscapa from the cullot elevator through a short vent pipe it the top. Thi3 dust should be extended to tho exterior of the building or other suitable point but should not be disposed at any considerable angle from the ver tical position because of the inovitable tendency for dust to settle in.it* It should be of heavy 3teel pipe since hammering will doubtless be necessary at inter vals to dislodge material accumulating on its -walla. Soma dust escapes ut the packing gland at the discharge of the Hardings nillo This is having the attention of Hr. Wiley who plan9 to replace the wood ^ ' packing with felt. Tho spout carrying tailings from the screen is worn and permits the escape of dust* This should be replaced with heavy steel pipe. WEIGHING Considerable dust results from hand weighing but since this process is to be supplanted shortly, no recommendations are rcado respecting it* Duet frem automatic weighing can bo eliminated by the installation of a simple arrangenwnt of i=xhust slots. Provide tvjo slots flanicing the bottom of tho t/eighing enolo3ure and arrange to exhauso a total of JjOO cfm0 Tho main branch connected to tho 3lota should be four inches in diameter and tho area of slots approximately 30-3*> squaro Recommendations on dust control prepared for Pittsburgh Corning Corporation, Port Allageny, Pennsylvania, February 13, lb, 19b6. 3 inches to give a face velocity of approximately 1500-2000 fpn. There is a four inch branch duct leading to the existing dust collector which can be connected et this point but it sould bo ascertained that the available suction is adequate to carry the specified bOO cfm at a velocity of not less than 3000 fpm0 If it is less than adequate then the branch diameter should be increased. % . SPRAYING Spraying of the molds takes place in well designed hoods, but some of the operators move the spray gun to the edge of the booth and force large quan tities of over-spray out into the room beyond the influence of the exhausto Inasmuch as plans are in process for new t'^pe of eoulpment involving automatic spraying no further attention was dovotad to this problem. FURNACE WITHDRAWAL AND LEHR FEEDING The dust and hot air generated at these two points were tho subject of special conversations at the plant. Tho hoods that were previously in uae above the entrance to the lehrs were describsd to us and the reasons for their removal. Wa can understand why they would have exposed workmont to currants of hot air and the resulting discomfort. Wa have illustrated in the attached sketch, tho nature of the air currents at the lehr entrance. It is important to understand tho il lustrated facta in order to proceed intelligently in the. design "of new ventila tion that will be adequate to remove duat and all hot air without subjecting rcrkmont to intolerable heat conditions. Recommendations on duct control prepared for Pittsburgh Corning Corporation Port Allegany, Pennsylvania, February 13, l/i, 19ii6o i U. Tno rolativo dsnsity *f room air nnd that within tne lehr results in the spillage of considerable* volumes of heated air outward through the uppsr _ portion of the open doorway, as illustrated* A canopy hood abovo this point can be ..designed to operate successfully provided it has air moving capacity at least equal to the rato of flow of hot air spilling out of the lohr0 The exhaust capa city sf the old hoeds was insufficient to accommodate all tho hot air delivered and the excess spilled outward around the bottom edges of the hood. There is no engineering data available that will enable even an apprcncLoate estimate of the rate of flow of hot air currants in such a situation and it is necessary therefore to resort to experiment. Thi3 is recommended* On the right hand aide of tho attached sketch, an experimental hood is illustrated which would cover half of the width of tho lehr end would bo equipped with an air restricting device to permit adjustment of air flow until observations indicate that all of the air is just being withdrawn into the hood with no spillage* A propallor fan, integral with the hood would serve for exhausting large air volumes from the experimental unit. Tho same hood could then be moved across tho aisle to tho point of withdrawal of molds from tho furnace and similar observations made* Ones data is available indicating tho required rato of exhaust it will b-j a 3itnple matter to decide on tho details of design of the full scale exhaust system Rocowandations on dust control prepared for Pittsburgh Corning Corporation, Port Allegany, Pennsylvania, February 13, lii, 19b6* 5 *> i EXHAUST SYSTEM FOR TRIMMING MACHINES Control of dust during normal operation of various trimming machines is excellent as judged visually and by dust counts previously made by Dr* Holden* However, thore is considerable settlod dust on tcp of the dust collector and other similar points indicating soma sources of dust not immediately evident* Investigation disclosed the following sources which are enumerated belcw together vith recommendations. Management is already familiar with many of these. 1 - SHAICINO DUST COLLECTCR It has been customary to operate the shaking mechanism of the dust collector for as long as IS minutes at the end of a shift* During this procsss, dust from the interior of the collector is carried out into the room. Th3 results from the fact that the entire* building is under a small suction sufficient to causs a reverse flow of air down through tho discharge duct, to tho fan (the fan being shut down), into the collector and outward through the exhause min and branches* It i9 recommended that a gate or valve be installed at a suitable point in the system that can be closed during the shaking. By preventing reverse air travel there will bo no medium for transport'of dust into the room. The valve ccn be located at either the discharge side of the fan in clean air or in side the du3t collector. It is unnecessary to operate tho shaking mechanism as long as is now the practice, A pariod of two to throe minutes ia customary. Recommendations on dust control prepared i'or Pittsburgh Corning Corp,,, Pert Allegany, Pa., February 13, lli, 19h60 60 The large diameter duct connecting tho main of thio exhaust system with th9 dust collector for the 3pray booths, etc., i3 a makeshift that can bo elim* inated with inauguration of the preceding recommendation,, There is probably a considerable accumulation of settled dust in portions of this duct which would eventually clog it completely,, Wo see no justification for attempting to maintain the arrangement as \ a standby in case of mechanical failure of existing dust collection equipment, since to bo effective it should be equipped with a large fan and motor similar to the present one. There are other more direct measures that would be cheaper,, 2 ~ HAMMER MILL Some dust escapes at the hammer mill located at the end of the waste collecting bslt,, Increasing tho rate of air exhaust from the existing enclosure would aggravate abrasion of the existing exhaust duct yet the process ought to have the benefit of a greater exhaust air flow. It Is thGi-ei'ore recommended that a vez'tical extension of tho existing chenber be installed four to five feet high, the exhaust duct connected at the top There would thus bo provided a trap for removal of oversize material that would otherwise be withdrawn into tho branch ducto 3 - ELEVATOR TO BELT At the point of discharge frem tho elevator onto the overhead collecting belt, a considerable volume of dust escapes that ia not immediately apparent be~ cause of tho enclosure0 ** Recommendations on dust control prepared for Pittsburgh Corning Corp*p . Port Allegany, Pa., February 13, Hi, 19U6,, 7o It in recommended that a three inch exhaust duct be installed to connect this point to the main duct. The connection should be made in such a manner as to avoid withdrawal of material not already floating in the air as dust and yet to exhaust from a confined space0 At the point of discharge onto the belt there are two conventional side skirt boards that are covered with cardboard* The latter should be replaced by steel plato and the 3" branch connected near the open end of the ''tunnel" so formed. It should be noted that we do not refer to the overall enclosure which does not serve any useful purpose* VENTILATION FOR MR* WALKER'S OFFICE The stuffiness complained of in this office i3 3aid to be partially a wintertime condition and partially summertime* It is apparent that the wintertime stuffiness is a result of insufficient air movement to dispel tobacco smoke and the like* In tho summertime this office is subject to full benefit of large quan tities of radiant heat from the adjoining roofo It i3 recommended that (a) A baffle di3po3ed at an angle be erected on the exterior design ed to make all near portions of the roof invisible from any point inside tho officeo (b) Provide the office with one-or two circulating desk fans0 (c) Install a vontilating fan having a minimum capacity of 200 efta to force air from the adjoining plant atnosphore into tho office* This arsall 3yotem should bo equipped with dust filter and an activated carbon ^ caniatcr odor absorbing unit* Particular care should be taken that fan selected will operate at a very low nol3o level* March 29s 19h6 Memorandum on Antimony Content of Duet Made for Pittsburg! Corning Corporation Port Allegany, Pennsylvania v> On 5aptaaber 6, 19lti?, a sample of air-born dust (FC-3) was collected frcen the breathing aone of a worker engaged in hand weighing batch for foaaglas,, The sample was analysed for antimony but none was detected,, This result was -unusual as foanglas batch contains a significant amount of that substance0 Curing a more recent visit to Fort Allegany, a sample of settled dust was obtained for the operation represented by PC-3, The material was separated Into two site fractions at the five micron level and the respirable portion (less than five microns) was analysed for antimony,, Th3 results are presented in Table 1,, Memorandum on Antimony Content of Dust mado for Pittsburgh Corning Corp*, Pore Allegany. Pa,s Mar* 29, 19ix6c 2C Table Ho0 3. Antimony Content of Respirable Sizes of Dust " Sample Number PC-10 Date 2/13/1x6 . '" ' Location and Onoi*stions ----- r I 1 ! -^n>- i Antimony content of dust under 5 microns -- ! !< *------*-- Sample of settled diet waa collected from lodges beside workman weighing foamglas batch by hando Ibis is a temporary con-" dition0 0*852 . Our data shows that tho respirable sic os of dust contain 0*852 of anti mony oxico calculated as antimony* '/hers is no generally accepted wavinma allow- able concentration for antimony* Houaverj the litoraturo on the subject indicates that it may possess a toxicity of the order of lead or mereuiy* If vs assume that antimony has a toxicity similar to that of lead (1*5 mgs* per 10 cu* n* of air)} than concentrations of dust from foainglas batch should not exceed IGO mgs* par 10 cubic meters of air* (0852 of 130 rags* would equal approximately 105 rags* of antimony*) A concontration of air-boma dust of thi3 order of magnitude would present an excasoivcly dusty atmosphere* Based on the analysis of PC-3 (Sept* 6, 19u5) report, ve balieve that conditions at Port Allegany aro much bolow this benchmark* We understand that tha condition of hand batch weighing will be dis continued in tho near future* Machine weighing with exhaust ventilation as out lined by Hr, Heraaon in hia report of Fobvuax-y 13 and llj, 19k6s will control tho dust* t * March 25(. 191x6 >s Francis K* Holden, Ph*D* Head Industrial Hygienist --------------- ----- ---------------- -------------------