Document pmYZXLgk0Y9NnxGrmLKrB6Gg6

THE BULLETIN OF THE AMERICAN CERAMIC SOCIETY y0Iume 20 APRIL, 1941 Number 4 BELL IEPHONE YSTEM System is doing & Country's program ional Defense. For tory xt psc 134 V -Txs of the ved on the i mixture 0f n crineral : the stonel "ever, may -imir.a-silica oxides t=ipera. 16. " Prevailed i at least up en vitrified aitial fusion tions would ay oxidizing wlack color carbon, de in the clay mcing flame ns probable i during the vers of glaze . ic of iron* onditions so ebtedness t0 Jniversity of nen and the the assist ed in making :ol 20. No. 4 gHGlNEERJNG CONTROL OF DUST WITH SPECIAL REFERENCE TO RESPIRATORS* By A. D. Brandt ' Abstract The more common methods of reducing or controlling the respiratory hazard caused by dust are discussed. The specific methods are (1) control of dust at the point of dust generation, (2) isolation of dusty processes, (3) substitution of noshazardous processes, and (4) reduction of dust in inspired air by respiratory protective devices. The general methods are (1) general ventilation, (2) good housekeeping, and (3) a rigid inspection of all control devices. A detailed discussion is given of respirators, their proper use, con struction, maintenance, and Bureau of Mines approval. 1. Introduction jdethods of dust control are not new, but the proper application of engineering principles to such methods is in many cases. Some industries are reluctant to call in qualified engineers to lay out their dust-con0ol plans. No one method, design, or device will solve the problem for all industries or in one large industry, gud only a thorough study of the existing conditions jan give the engineer a basis on which to determine the kst method or combination of methods for the problem or industry in question. The important methods of dust control are (1) con trol at the point of generation or dissemination, (2) eolation of dust-producing processes, (3) substitution of less hazardous materials, and (4) reduction of dust in ^spired air by means of respirators. (2) Ducts and Collector The ducts include all piping through which the dusts are carried from the hoods to the collector by the air current created by the fan. The final part of the sys tem is the collector, which retains the dust and permits the dean air to escape into the atmosphere. Routine inspection and maintenance are important. The ducts are dogged all too frequently with worn-out overalls or similar waste materials; properly designed systems are unbalanced by having the tinsmith put in additional branch ducts and exhaust hoods; collectors are not emptied; and bags of collectors are torn or even removed and not replaced. Inspection and main tenance can ensure successful operation for a reasonable period of time. II, Control at Point of Generation or Dissemination The methods commonly used to control dust at the point of origin are (1) local exhaust ventilation equip ment, (2) water or other suitable liquids, and (3) good housekeeping. A local exhaust ventilation system consists of (1) exhaust hoods, (2) air ducts, (3) collec tor, and (4) fan. . (1) Hoods The purpose of an exhaust hood, which is the vital part of the system, is not to create "suction" but to produce air currents in the area of dust generation of suitable magnitude and acting in the proper direction to overcome the energy of the escaping particles and to carry them into the exhaust system. A knowledge of the laws of air flow into suction openings of various shapes is therefore essential to proper design. A thorough understanding of the way in which dust is generated is also necessary, especially as it pertains to particle size and to the velocity at which the particles *re thrown off. An efficient hood collects the dusts {aerated with a minimum air flow from the ineffec tive or clean air areas and with minimum power conffinption. A hood is properly designed when it (1) is tffident and (2) does not hinder the operation of the tool OT mar-bint* * Presented at the Forty-Second Annual Meeting, The American Ceramic Society, Toronto, Canada, April 8, (General Session on Toxicology). Received April 9, (3) Fan To avoid the wear of fan blades and bousing resulting from the abrasive action of the dust, the collecting unit should be located on the suction or upstream side of the fan. (4) Spray Wetting down with water by hand or by sprays or streams is a method of control at the point of origin that is widely used. Water helps temporarily to lay dust, and a stream carries away many particles, but the procedure is fundamentally impracticable as an effec tive safeguard. It is impossible to wet most of the par ticles by the usual means owing to the gas layer which envelops them. Few particles are collected and con sequently many of those that are temporarily wetted will remain in suspension owing to evaporation of the surrounding layer of water before complete settling has taken place. When other methods are not available or are impracticable, however, the use of a water stream is worth while. (5) Good Housekeeping Good housekeeping as a means of dust control is possibly the least difficult and least expensive to em ploy and frequently accomplishes remarkable results. It prevents dust accumulations in any part of the plant where the dust may be redispersed by careless operation, shock, or wind currents. Such dust may be wetted down and removed frequently and permanently. Fre quent and regular use of large vacuum diners on OWl) 123 124 Bulletin of The American Ceramic Society--Brandt beams, rafters, or other inaccessible places is also help ful in solving this problem. 111. Isolation of Dust-Producing Processes The isolation of dust-producing processes limits the exposure to a few men who may be protected by res pirators. The indosure of these processes in dusttight chambers or rooms, such as abrasive blasting cabinets, is effective. The chambers and dust-control devices, however, must be kept in good working condi tion to maintain their effectiveness. IV. Substitution of Less Hazardous Materials The substitution of less hazardous materials offers an absolute method of dust control, but extensive changes in the manufacturing process are often required which may not be practicable. This method should not be recommended Mnfcss or until it is established that the quality of the manufactured item will not suffer by such change. The replacement of sandstone grinding wheels by artificial abrasive wheels and sand by steel shot in abrasive blasting has effected a substantial re duction in the silicosis rate of the pertinent industries. wearer. A filter respirator which is to be accepted ^ industry as satisfactory should (1) be comfortable an)j fit the face well, affording an air-tight contact betw-_/ the face and the mask, (2) have little or no interfex^31 with vision and permit the use of glasses or goggj^ (3) have a highly effective filter which is not bulky have low resistance to breathing over a period of Us^ (5) have small dead air space, and (6) have both inh^' tion and exhalation valves. ' Dust respirators are usually constructed of a mbbty or part-rubber facepiece and a filtering medium of felted or paperlike material Exhalation valves are now almost universal, and inhalation or check valv^ are supplied in most respirators. Inhalation valvjj are intended to prevent (1) rebreathing exhaled air and (2) the humid exhaled air from getting into and fouling the filter. Rebreathing exhaled air, which has a high carbon dioxide content, induces panting aDlj causes the wearer to think that there is a lack of air or that theresistance to breathing is high. He will attempt many solutions to eliminate these difficulties, all ^ which will seriously impair the performance of the respirator. V. Use of Respirators for Reduction of Dust in Inspired Air Respirators are misused and abused more than any other dust-control device. The amount of dust in the inspired air may be re duced to a safe value by suitable respiratory protective devices. These alone are not the solution to many of the dust-control problems in industry, but they are a necessary and helpful adjunct to other methods. Al though there are a number of different types of respira tors, the two types which are used most commonly in dust control are (1) the mechanical filter or dust respira tor and (2) the supplied-air or air-line respirator and abrasive blasting helmet. These respirators are used extensively on jobs such as abrasive blasting, paint chipping, handling used storage battery plates, cad mium oxide manufacture, welding operations, spraying of paints and glazes, and manufacture and use of pig ments and dyes. Their most important use is found under conditions where protection is required inter mittently, as in cleaning-out operations; sweeping; after blasting; removing cores from large foundry' cast ings; shoveling, screening, and handling of materials; and the operation and maintenance of processing equip ment. Respirators should not be considered to be part of the worker's wearing apparel. They are safety devices and should be supplied by the employer. The em ployer, moreover, must see that they are distributed to all employees who need them, and he must tell the workers when and how to use them, which is a difficult task and is accomplished only by incessant instruction. (1) Mechanical Filter Respirators . When the mechanical filter respirator is worn on a man's face, a certain percentage of the dust is filtered out from the inspired air. The air movement through the filter is produced by the respiratory action of the (2) Supplied-Air Respirators or Helmets The air-line respirator and the abrasive blasting helmet are the supplied-air devices most commonly found in industry. The respirator consists of a fa mask with an attached hose or rubber tube through which air is supplied, and the air is pumped or blown from a source of clean air to men in the various expo sures. These devices afford positive protection if they are properly installed and maintained. The intake to airsupply systems used for this purpose must be located at a point where the air is clean and where it will not be contaminated by dust from nearby buildings. For the removal of oil, water, and odors from the air, a good air cleaner or purifier should be installed in the supply lice. The cleaners, however, do not remove carbon monoxide which may be given off in antiquated or worn compres sors. To avoid the possibility of carbon monoxide poisoning in men wearing supplied-air respirators, it is imperative that the air pump or blower should receive adequate routine inspection and periodic overhauling. The abrasive blasting helmet completely incloses the wearer's head, forming a seal at the neck and shoulders or having a directly connected cape which may be tucked in under an over-all jacket or may be even extended to the waist. Blasters move about very little, but the helmet should be light in weight and the window or port which affords vision should be large and correctly placed. If the helmet is too small, a large volume of air must be supplied to prevent an undesirable decrease in the pressure within the helmet when the wearer inspires. The volume of air supplied to a helmet should be sufficient to provide a continuous leakage outward. Some helmets require only about 100 liters per minute; others require twice this amount. The air should be wasted through the collar or down around the neck and out through the clothing. Collars should be permeable to air to eliminate the possibility of building up a dangerous pressure within the helmet Vol. 20, No. < blast fro*1nsat a stro /3) $lectic ' /pjje hazard tors iaindust t0 recomment it is to expect iat each diffe: same respirat* *ear if be of quartz- Ir any parucula editions as jjiendaticns fi ^ S- Bureau (4) Care an Recause tb jeetbods of c thought is gi' quently good carefully, and are dirty and The respira properly mail protection, e- ously. A def none because security and he would take Individual: eral systems In the iudivi upkeep of the wash, sterilize tral maintena at one central The centra out somewba respiratory p which are m user by stanr metal numbe: laundry tabs ( in the mornir holes in one number) he fi the close of 11 tor in the pig collected by c room laid ou worker is suf between shift however, and man on the r respirator mr worker. He r or any indivi tenance of r with that of : hats. In son * accepted by importable and ontact between 20 interference 'cs or goggles, not bulky, (4) period of use ve both inhala- -.ed of a rubber -g medium of 'on valves are x check valves lalation valves ng exhaled air ixtiug into and . air, which has 3 panting and a jack of air or tie will attempt mculties, all of ^nnance of the !met* '-asive blasting most commonly nsists of a face x tube through imped or blown it various exporotection if they The intake to airaiust be located ere it will not be idings. For the ie air, a good air 1 the supply line, rarboa monoxide r worn compres,,-bon monoxide respirators, it is x should receive die overhauling, ipletely incloses t the neck and rted cape which iet or may be 2rs move about light in weight vision should be met is too small, .-d to prevent an -ithin the helmet * of air supplied ide a continuous *e only about 100 ice this amount. collar or down lothing. Collars ie the possibihty Ithin the helmet. Vo!. 20, No- 4 Engineering Control oj Dust with Respirators 125 crposed escape valves are unsatisfactory because dust jjojn a blast may easily be driven into the helmet ^aisst a strong air current. (3) Selection of'Respirator - Tbe hazards as well as conditions of use of respira tors in industry are many and varied. It is as illogical ^ recommend the same respirator for all purposes as t js to expect to find a respirator specifically designed for each different operation. No worker would use the ^joe respirator for hay-fever prevention that he would if he were exposed to a dangerous concentration 0f quartz. In the selection of the proper respirator for gjjy particular operation, the buyer should specify the editions as fully as possible when asking for recom mendations from respirator manufacturers or from the y. S. Bureau of Mines. (4) Care and Maintenance of Respirators Because the use of respirators, compared to other methods of dust control, is inexpensive, little or no fought is given to their maintenance. Only too fre quently good respirators are purchased, distributed carefully, and then forgotten, and in a short time they are dirty and function ineffectively. The respirator will soon become defective if it is not properly maintained and will fail to give the necessary protection, even if it is worn correctly and continu ously. A defective respirator, moreover, is worse than aooe because the wearer is given a false feeling of security and will not exercise the precaution which be would take if he had no respirator. Individual and central maintenance are the two gen eral systems of respirator maintenance in use today. In the individual maintenance system, the care and upkeep of the respirator is left to the user, who must wash, sterilize, and repair the respirator. In the cen tral maintenance system, all respirators are assembled at one central point for cleaning aad repairing.1 The central maintenance system usually is worked out somewhat as follows. Each worker who needs respiratory protection is supplied with two respirators which are marked with the employment number of the user by stamping the number on metal parts, riveting metal number plates on the rubber masks, or sewing laundry tabs on the headbands. When he goes to work in the morning, the worker passes by a row of pigeon holes in one of which (indicated by his -employment number) he finds a dean and well-kept respirator. At the dose of the shift, he again places the dirty respira tor in the pigeonhole. All of the dirty respirators are collected by one man who cleans and repairs them in a room laid out for this purpose. One respirator per worker is sufficient if the maintenance is carried out between shifts. Two respirators usually are supplied, however, and the repairs and deaning are done by one man on the regular shift. The worker in charge of the respirator maintenance need not be a new or spedal worker. He may be the man in charge of the stock room or any individual whose work will permit. The main tenance of respirators may frequently be combined with that of such equipment as goggles and protective bats. In some industries where relatively few respira- (IHl) tors are in use, the maintenance is one of the duties of the nurse. The advantages of the central over the individual system are obvious. Each worker has a dean, well- kept respirator daily. He will object less to wearing it and will get real protection at all times. The mone tary saving effected by the increased life of the parts and decreased need for new respirators usually will more than offset the additional cost (if any) of setting up and maintaining the central system. The idea of a central maintenance bureau is not a new one. Such bureaus have been in use in a number of industries for several years. The results produced are remarkable, as evidenced by the condition of the respirators and the apparent satisfaction of the users. Respirator maintenance usually consists of deaning, sterilizing, and repairing. Effective methods of dean ing and sterilizing are (1) wash in warm water with a brush and soap; (2) immerse for ten minutes in a solu tion of formalin, made by placing 1 part of 40% for maldehyde solution into 9 parts of water; (3) dip in a 3% solution of carbolic acid, a 2% solution of iysol, or a 70% solution of denatured alcohol; or (4) subject the respirator to sterilization by a moist atmosphere of an tiseptic gas, preferably formaldehyde, for a period of 10 minutes at room temperature. After following any one of these procedures, the respirator should be rinsed with water and hung up to dry. The filters, felt screens, and headbands (if elastic) must be removed before deaning or sterilizing the respirator. Many dust respirators employ so-called "long-life" filters which are intended to be used over and over. Such filters are deaned by blowing the dirt or dust off with compressed air, by brushing the surface, or by tapping the filter. If the filters are moist, they must be dried before the dust can be removed effectively. Tbe filters may be dipped in a dry-cleaning solution for a short time to remove grease and the like. This process, however, should be carried out only infrequently be cause it decreases the life of the filter. ,' ' V!. Bureau of Mine* Approval Dust respirators are tested and approved by the U. S. Bureau of Mines under Schedule No. 21 entitled "Procedure for Testing Filter-Type Dust, Fume, and Mist Respirators for Permissibility," and supplied-air respirators are tested and approved under schedule No. 19A entitled "Procedure for Testing Supplied-Air Respirators for Permissibility." . . The only important difference between the air-line respirator and the abrasive blasting helmet is that the latter provides protection to the face and head of the wearer from the rebounding abrasive. Seven supplied-air respirators of this type are ap proved; two are air-line respirators and five are abra sive blasting helmets. The U. S. Bureau of Mines, through these approval schedules, has done a great deal to raise the standards of the respiratory protective devices manufactured in the United States and has been of great service to industry in the selection of the proper devices. Wiluon Pxooocrs, Ikcoimutid Rxadino, Pennsylvania ' THE BULLETIN OF THE AMERICAN CERAMIC SOCIETY yjclufTte 20 Contcnb for August/1941 Number 8 LEM? ERViCE ON , .laze Staies 3-glaie Colors crs i Mediums m &nd Lustre *QS d Chemicals equipment ad Linings itex Mil! Linings $ t in the Ceramic U PAPERS Twcription of Hot Modulus of Rupture and Hot Crushing Strength Tests and Discussion of Results-- B. Hunt and R. S. Bradley................................................................................................................................. 267-69 Multiple-Tunnel Kilns--M. S. Nelson and Hewitt Wilson....................................................................................... 270-74 peairing Fine Clay Bodies in the Plastic Form--E. A. Hawk................................................................................. 274-75 p-efabricated Structural Clay Tile Floor System--E. F. Wanner........................................................................... 276-80 Experimental Study of the Inhibitory Effects of Aluminum Compounds in Silicosis--Leroy U. Gardner, Morris Dworski, and Anthony B. Delahant......................................................................................................... 2S1.2S4 Industrial Health Service for the Small Plant in the Ceramic Industry--Huntington Williams, W. H. Schulze, and J. M. McDonald.................................................................................................................................. 2S5-S7 Discussion on "Symbolism in Chinese Porcelain Decoration"--Lawrence E. Barringer.................. ............. 287-88 ^rtrtisen'Index............................................ 6 Sipn' Guide...................................................................................................................................................................... 12, 16, 18, 20 Ixbrof Corporation Members........................................................................................................................................................294-95 INDEX TO CERAMIC HISTORY, ACTIVITIES/ NOTES Cnaie history, Pittsburgh Plate Glass Company, pp. 288-90. (naic schools. New York State College of Csamics, Electro Refractories & Alloys with Industrial Minerals Diviaon of Photographs, Brown, Charles. W.. o. 289. A.I.M.M.E., p. 290. Clause. Robert L.. p. 290. new members, p. 291. Clause, W. L., p. 289. new research laboratory of Metal & Thermit activities during 1940-1941. p. 296. .,. , t n 292. "em p * " fecora' Pitcairn. John, August cover. dcw, for July, p. 292. Wbewtt, H* S., p. 290* 9- 291- roster changes during July'p 292 ^ faeture. p. 2&8: photo. August cover, ftijevthipt at Edward Orton. Jr.. Ceramic Moral A Th,rmi> nwirrh Pinsbnrgh Plate Glass Company, history. Foundation for. 1941-1942, p. 296. . laboratory, pbow/p. 296 PP- 288-90. v x. btate college oi ceram.es, p. iao. 'an. plate-glass manufacture by Pittsburgh Plate Glass Company, pp. 288-90. Ceramic Exhibition (tenth annual) laboratory, photo, p. 296. mt Museum of Fine Arts. p. 297. Syracuse Museum ef Fine Arts.sponsors tenth National Ceramic Exhibition, Publication Office: 20th & Northampton Sts., Easton, Pm. . Editorial, Executive, and Advertisint Office:: 2825 N. High SC. Columbus. Ohio. . Committee on Publications: J. D. Scu-ivax, Chairman; D. E. Soaxf, E. E. MjUessxbk, J. B. Austin, Ross C Puidv. Entered as second-class matter at the post office at Easton, Pa., under the act of March 3, 1879. Published monthly. Subscription SI.SO a year. Single numbers twenty-five cents. -* (Foreign and Canadian postoec, S0i additional on subscriptions) * (Copyri(ht 1941, American Ceramic Society, Int.) -I '.I i ' j T Bui ROSTER OF PAID CORPORATION MEMBERS Abb4 Engineering Co., New York, N. Y. Abingdon Sanitary Mfg. Co., Abingdon, HI. A C Spark Plug Co., Flint, Mich. Adamston Flat Glass Co., Clarksburg, W. Va. Akron Porcelain Co., Akron, Ohio American Gas Assn., New York, N. Y. American Glass Corp., Greensburg, Pa. American Lava Corp., Chattanooga, Tenn. American Nepheline CorpM Rochester, N. Y. American Porcelain Enamel Co., Muskegon. Mich. American Potash A Chemical Corp., New York, N. Y. American Refractories Institute, Pittsburgh, Pa. American Rolling Mill Co., Middletown, Ohio American Stove Company, St. Louis, Mo. Amsler-Morton Co., Inc., Pittsburgh, Pa. Anchor Hocking Glass Corp., Lancaster, Ohio Arketex Ceramic Corp., Brazil, Ind. Armstrong Cork Co., Lancaster, Pa. Atlantic Terra Cotta Co., Perth Amboy, N. J. Empire Sheet A Tin Piste Co., Mansfield. Ow Engelhard, Charles, Inc., Newark, N. J. English China Clays Sales Corp., New York, N v Eureka Flint A Spar Co., Trenton, N.J. ' ' Exolon Company, Blasdell, N. Y. Fabrics de Ladrillos Industrials y Refractari terrey, N. L., Mexico Fairiacts Company, Inc., Trenton, N. J. Federal Seaboard Terra Cotta Corp., Perth Ambe* v Ferro Enamel Corp., Cleveland, Ohio " J. Ferro Enamels (Australia) Pty. Ltd., Alexandria x- Australia Findlay Clay Products Co., Washington, Pa. ' Foote Mineral Co., Philadelphia, Pa. Fords Porcelain Works, Perth Amboy, N. J. Fostoria Glass Co., Moundsville, W. Va. Frazier-Simplex, Inm, Washington, Pa. Babcock A Wilcox Co., New York, N. Y. Ball Brothers Co., Muncie, Ind. Baltimore Enamel A Novelty Co., Baltimore, Md. Bardin, Paul, e Hijos, Soc. Anon. Com., Buenos Aires, Argentina, South America Bausch A Lomb Optical Co., Rochester, N. Y. Belden Brick Co., Canton, Ohio Blue Ridge Glass Corp., Kingsport, Tenn. Bonnot Company, Canton, Ohio Braun Corp., Los Angeles, Calif. . Brockway Glass Company, Inc., Brockway, Pa. ' Buck Glass Company, Baltimore, Md. Buffalo Pottery Co., Buffalo, N. Y. Garco Products, Inc., Butler, Pa. Gayser Glass Works, Salem, N. J. General Ceramics Co., New York, N. Y. General Electric Co., Lamp Dept., Pitney Glass tl- , Nela Park, Cleveland, Ohio George, W. S., Pottery Co., East Palestine, Ohio Gillinder Brothers, Inc., Port Jervis, N. Y. Gladding, McBean A Co., Lincoln, Placer Count? r i-, Gleason-Tiebout Glass Co., Maspeth, N. Y. ' UJl<- Glenboig Union Fireclay Co., Ltd., Glenboig, Scotland Great Lakes Foundry Sand Co., Detroit, Mich. Great Lakes Steel Corp., Detroit, Mich. Green, A. P., Fire Brick Co., Mexico, Mo. riiwariifln General Electric Co., Ltd., Peterborough, Ontario, Canada Canton Stamping A Enameling Co., Canton, Ohio Carborundum Company, Niagara Falls, N. Y. Carnegie-HIinois Steel Corp., Pittsburgh, Pa. Carr-Lowrey Glass Co., Baltimore, Md. Celo Mines, Inc., Burnsville, N. C. Central Silica Company, Zanesville, Ohio Ceramic Color A Chemical Mfg. Co., New Brighton, Pa. Ceramics Publishing Co., Inc., Newark, N. J. ' Certain-Teed Products Corp., Buffalo, N. Y. Champion Spark Plug Co., Detroit, Mich. Chattanooga Glass Co., Chattanooga, Tenn. Chicago Hardware Foundry Co., North Chicago, 111. Chicago Pottery Co., Chicago, 111. Chicago Vitreous Enamel Product Co., Cicero, 111. Clark, N., A Sons, San Francisco, Calif. Colonial Insulator Co., Akron, Ohio Commercial Decal Products, Inc., East Liverpool. Ohio Consolidated Feldspar Corp., Trenton, N. J. Coors Porcelain Company, Golden, Colo. Corhart Refractories Co., Inc., Louisville, Ky. . Coming Glass Works, Coming, N. Y. Crane Eaamelware Company, Chattanooga. Tenn. Crooksvilie China Co., Crooksville, Ohio Cros&ley Machine Co., Trenton, N. J. Crossman Company, South Amboy, N. J. Crown Potteries Co., Evansville, Ind. DeVilbiss Co., Toledo, Ohio Dixon, Joseph, Crucible Co., Jersey City. N. J. Drakenfeld, B. F., A Co., New York, N. Y. Du Pont de Nemours, E. L, A Co., R. & H. Chemicals Dept., Wilmington, Del. Edgar Plastic Kaolin Co., Metucben, N. J. Electric Auto-Lite Co., Fostoria, Ohio . Electro Refractories A Alloys Corp., Buffalo, N. Y. Haeger Potteries, Inc., Dundee, 111. Hall China Company, East Liverpool, Ohio Hancock Brick A Tile Co., Findlay, Ohio Hanley Company, Summerville, Pa. Hanovia Chemical A Mfg. Co., Newark. N. J. Hardinge Company, Inc., York, Pa. Harshaw Chemical Co., Cleveland, Ohio Hartford-Empire Co., Hartford, Conn. Haws Refractories Company, Johnstown. Pa. Hazel-Atlas Glass Co., Wheeling, W. Va. Hommel, O., Co., Pittsburgh, Pa. Houze, L. J., Convex Glass Co., Point Marion, Pa. Humphryes Manufacturing Co., Mansffeld, Ohio Hygrade Sylvania Corp., Emporium, Pa. - Illinois Clay Products Co., Joliet, 111. Industrial Ceramic Products, Inc., Columbus, Ohio Ingram-Richardson Mfg. Company of Indiana, Inc, Frankfort. Ind. International Clay Machinery Co., Dayton, Ohio International Smelting A Refining Co., Akron, Ohio Ironton Fire Brick Co., Columbia, S. CIsolantite, Incorporated, Belleville, N. J. Jova Brick Works, Roseton, N. Y. Kaolin, Incorporated, Spruce Pine, N. C- Kentucky Clay Mining Co., Mayfield, Ky. Kentucky-Tennessee Clay Co., Mayfield, Ky. Knowles, Edwin M., China Co., Newell, W. Va. Kohler Company, Kohler, Wis. Koppers Company, Pittsburgh, Pa. Kraftile Company, Niles, Calif. Laclede-Christy Clay Products Co., St. Louis, Mo. Lancaster Iron Works, Lancaster, Pa. Lapp Insulator Co., Inc., Le Roy, N. Y. Laughlin, Homer, China Co., Newell, W. Va. Lava Crucible Co. of Pittsburgh, Pittsburgh, P,a. 294 Vol.20.S*s ' tyc . field Saw* $g:^< GlM* Bot Refractc esiopi Glas ggss **f*Munge; Tile Cor 5HSSSSS 5* Gyps: iefr ssissjs porton Company Ohio Clay Co C OhioHydrateA Ohio Insulator C Ohio OWSi*oryCI. Olean Tile Co., v Onondaga Pottei Orefraction, Inc. Orton, Edward, Owens-Illinois G Owens-Illinois P pacific Clay Prod pacific Coast Bo: Pacific Tile A Pc Paper Makers In Pass A Seymour. Pennsylvania Pu! Pennsylvania Sal Pfandler Compaz Pittsburgh Plate Porcelain Ename Porcelain Produi Portsmouth Clay Potters Supply C< Precision Grindi: Quigley Company Runtite Co., Chi Rinsome Concre fctmmey, Richar ( AI 0941) pxlUlin of The American Ceramic Society--Roster of Corporation Members 295 i ^Ancts Company, Clearfield, Ky. 1 ^WoSptar. Toledo, Ohio Gliss Co., Toledo, Ohio Corp., Baltimore, Md. ^^T^factuiing Co., East Liverpool. Ohio ^^03-, Los Angeles, Calif. /* ciflitary Pottery. loe, Perrysville, Ohio 'Y. AtfifuSs Corp., Baltimore, Md. Al3?des- Caiif- #> f"3" Inc, Perth Amboy, N. J. * 4 Co., Cleveland, Ohio Corp., New York, N. Y. Bottle Co., Jersey City. N. J. 5* factories Co., Mexico, Mo. ,!>^fSss Co., New York. N. Y. KSjL* Mfg- Co., St. Louis, Mo. RSSefiflf * Mfg. Co., West Lafayette, Ohio .SjtfrBfer,New York*N-Y- y*T Tfle Company. Zanesville, Ohio r^OcsBens Pottery Co., Mount Clemens, Mich. ass w, aio s*. c*ii{> 5co^l4od i**ifirepT00fo: Corp, Pittsburgh, Pa. M^7i Gyp*nm Co., Clarence Center, N. Y._ W^\ Itnnddmosrt^ri*al Sand Assn., Washington, D. C. rd Co., Brooklyn, N. Y. cniJlime *od Stone Co., Findlay, Ohio mrlstle Refractories Co., New Castle, Pa. rgej prWoWrcCeilMainI CWVo.,, TArteMnVtVoUn.l NAS.. JJ..___ JjUjy pulverizing Co.. New York, N. Y. Gtishi Kabushiki Kaisha, Nagoya, Japan ^okj y.igba, Ltd., Nagoya, Japan ftjfijnericAti Refractories Co., Cleveland, Ohio Jjjr gjjoiioa Feldspar Corp., Erwin, Tenn. ^mpany, Worcester, Mass. - . Oj. Co., Cleveland, Ohio Joydrate & Supply Co., Woodville, Ohio JInsulator Company Div., Ohio Brass Co., Barberton, iffickory Clay Co., Paducah, Ky. J?rue Co., Olean.N.Y. Zfijift Pottery Co., Syracuse, N. Y. wnction, lac., Pittsburgh, Pa. Edward, Jr., Ceramic Foundation, Columbus, Ohio -af.Tffinois Glass Co., Alton, 111. s-Blinois Pacific Coast Co., San Francisco, Calif. )hio ana, Inc., cUf Products, Los Angeles, Calif. _*2e Coast Borax Co., New York, N. Y. Tile 4 Porcelain Co., Los Angeles, Calif. %e Makers Importing Co., Inc., Easton, Pa. Seymour, Inc., Solvay, N. Y. 'ta^iunia Pulverizing Co., Lewistown, Pa. teyinaia Salt Mfg. Co., Philadelphia, Pa. ww Company, Rochester, N. Y. . tehsrgh Plate Glass Co., Creighton, Pa. Irakis Enamel 4 Mfg. Co., Baltimore, Md. takin Products, Inc., Findlay, Ohio tomofith Clay Products Co., Portsmouth, Ohio ter Supply Co., East Liverpool, Ohio 9QS0Q Grinding Wheel Co., Philadelphia, Pa. iad*7 Company, lac., New York. N. Y. . e$te Co., Chicago, 111. ae Concrete Machinery Co., Dunellen, N. J. y, Richard C., Son Co., Philadelphia, Pa. Republic Steel Corp., Youngstown, Ohio Rickman 4 Rappe, Koln-Kalk, Germany Riddell, W. A, Co., Bucyrus, Ohio RoteTille Pottery Co., Zanesville, Ohio Ross-Tacosy Crucible Co, Philadelphia, Pa. Rimdie Manufacturing Co., Milwaukee, Wls. Rnstleas Iron Co, Ltd, Keighley, England Safety Grinding Wheel 4 Machine Co., Springfield. Ohio San Miguel Brewery, Inc, Manila, P. I. Sehundler, F. ., 4 Co., Lie., Joliet. 111. Seagram, Joseph E., 4 Sons, Lie., Louisville, Ky. Shenango Pottery Company, New Castle, Pa. Simoads Worden White Co., Dayton, Ohio Smith & Stone, Ltd., Georgetown, Ontario, Canada Solvay Process Company, Syracuse, N. Y. Spinks, H. C., Clay Co, Newport, Ky. Square D Company, Detroit, Mich. Standard Brick and Tile Corp., Evansville, Ind. Standard Lime 4 Stone Co., Baltimore, Md. Standard Sanitary Mfg. Co, Louisville, Ky. Star Porcelain Co., Trenton, N. J. Stark Brick Co., Canton, Ohio Stauffer Chemical Co, Inc., New York, N. Y. Steele, J. C, 4 Sons, Statesville, N. C. Sterling Grinding Wheel Co, Tiffin, Ohio Structural Clay Products Institute, Washington, D. C. Stupakoff Laboratories, Inc, Latrobe, Pa. Swmmjtville Face Brick Co, Summitville, Ohio Sur Enamel 4 Stamping Works, Ltd., Calcutta, India Surface Combustion Corp., Toledo, Ohio Swindell Brothers, Baltimore, Md. Swindell-Dressler Corp, Pittsburgh, Pa. Taylor, Smith, 4 Taylor Co, Chester, W. Va. Texas Mining 4 Smelting Co, Laredo, Texas Titanium Alloy Mfg. Co., Niagara Falls, N. Y. Toyo Toki Kaisha, Kokura City, Japan Trenton Potteries Co., Trenton, N. J. Twyfords, Limited, Stoke-on-Trent, England Tyler, W. S, Company, Cleveland, Ohio Union Electrical Porcelain Works, Inc., Trenton, N. J. United Clay Mines Corp, Trenton, N. J. United Glass Bottle Mss., Ltd., London, England United States Gypsnm Co, Chicago, Hi. Universal Clay Products Co, Sandusky, Ohio Universal Dental Co, Philadelphia, Pa. Universal Sanitary Mfg. Co, New Castle. Pa. Vanderbilt, R. T, Company, New York. N. Y. Vereeniging Brick 4 Tile Co, Ltd, Vereeniging, Transvaal, South Africa Vesuvius Crucible Co, Swissvale. Pa. Victor Insulators, Inc., Victor, N. Y. Vitrefrax Corporation, Los Angeles, Calif. Vitreous Steel Products Co, Cleveland, Ohio Vitro Manufacturing Co, Pittsburgh, Pa. Wallace China Co, Ltd., Huntington Park, Calif. Waltham Grinding Wheel Co, Waltham, Mass. Washington Porcelain Co, Washington, N. J. Wayne Laboratories, Waynesboro, Pa. Western Brick Co, Danville, 111. Western Electric Co, Chicago, HI. Westinghouse Electric 4 Mfg. Co, Deny, Pa. West Virginia Brick Co, Charleston, W. Va. Wheeling Steel Corp, Yorkville, Ohio Wisconsin Porcelain Co, Sun Prairie, Wis. CORPORATION MEMBERSHIPS I ARE PROFITABLE INVESTMENTS 20. No- s ton The / Amencan / * ^ Ceramic / & Society / February 15,1993 I hereby certify that the attached copies of Bulletin of the American Ceramic Society, Volume 20,1941, are true and accurate copies, which are maintained in the normal course of business at the American Ceramic Society, 735 Ceramic Place. Westerville, Ohio 43081. Christine Schnitzer Product Manager Ceramic Information Center 735 Ceramic Place Westerville, Ohio 43081-8720 614*890*4700 TWX: 7101109409