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t. 1 Other Volumes in this Series VOLUME 4 1953 TRANSACTIONS Usfrs of this volume will find much value in its companion volumes. Here is the list: TITLE VOLUME No. General Sessions and Detailed Index to all Volumes.............................................................. 1 Aeronautical Industries .................................................................................................................... - Air Transport Industry.................................................................................................................... ^ Automotive and Machine Shop Industries..................................................................................... - Cement and Quarry Industries........................................................................................................ : Chemical Industries .......................................................................................................................... r. Coal Mining Industry ...................................................................................................................... Construction Industry* ...................................................................................................................... i Electrical Equipment Industry........................................................................................................ '* Farm Safety....................................................................................................................................... K Fertilizer Industry ...............................................................................................................................................V. Frod Industry ................................................................................................................................................................... IGlass and Ceramics Industry............................................................................................................................................ l.: K<:nc Safety....................................................................................................................................... 1- Industrial Nursing ......................;................................................................................................................................. It Industrial Subject 5cssi"ns (Sj-'*tt>*rcd by ASSKl............... 1' Maritime Industries (MarineSection)........................................................................................................................ 1. Meat racking. Tanning and Leather Industrie*.............................................................................................. i* Metals Industry .............................................................................................................................................................................. ' Mining Industry ........................................................................................................................................................................ M<t*.r Transjmrtati'.n Industry (Commercial Vehicle Section!............................................................... 2! Petroleum Industry ................................................................................................................................................................... ~ I'ower Prc** and Forging Oj>cr;tt<*nw.............................................................................................................................23 Frinting and Publishing Industry.................................................................................................................................... 2- Public Employment c Public H:r.|>h*yee>Safety Committee t.......................................................................... 2: Public Ltiiit'cs Industrie*......................................................................................................................................................... 2-*. I'niji and Paper Industry............................................................................................................................................................2/ Railroad Industry....................... 2i Rublr Industry ........................................................................................................................ -* Sci'**l and College Safety.................................................................................................................................................... c Textile Industry ........................................................................................................................................................................... 51 Tn*mc Safety ................................................................................................................................................................................ 5- Tn-nsit Industry ..............................................................................................................................................................................v JVotluets Industrie.................................................................................................................................................... Safety and It? Relationship to Personality.............................................................................................................. 5.* PRICES OF EXTRA COPIES OF INDIVIDUAL VOLUMES TO MEMBERS VOLUME I to 9 copies SIZE Each Le?s than 24 pages-- $0-29 24 to 48 pages-- 25 49 to 96 pages-- Over 96 pages-- .46 .69 JO to 99 copies Each $023 29 .40 .63 100 to 999 copies Each $0.17 23 25 -58 1000 or mart Each S0.I7 23 25 28 Complete set ni Transactions (35 vols.)--$6.90 (1 to 9 copies), 6.30 (10 to W copies;. 5.70 (100 or more copies). XOX*MEMi#EK prices arc double member prices, except volumes 10, 14. 30 and 32. | | Current Safety Topics in the 1 AUTOMOTIVE AND I MACHINE SHOP I INDUSTRIES os presented in sessions of the Automotive and Machine Shop Section at the 41st National Safety Congress Checking Performance of Process Exhaust Systems 4 Haunts in Set.up. Handling and Storage of Power Press Dies... 8 Fundamental Principles of Machine Guarding. 10 S C F-A LLF-01395 NATIONAL SAFETY COUNCIL 425 NORTH MICHIGAN AVE, CHICAGO 11. ILL PBItTIS IB e.s * s NATIONAL SAFETY COUNCIL 425 North Michigan Avenue Chicago 11. Ill Officers of the AUTOMOTIVE AND MACHINE SHOP SECTION NATIONAL SAFETY COUNCIL 1 953-54 General Chairman--CARL .1. PETERSON, Slat? Saiclv Engineer, Chrysler Corporally Detroit, Mich. ' I'icr-Chain.uin--MICHAEL F. B1ANCARDI, Mgr-. Health and Safety Depanmer.-. Allis-Chalmers Manufacturing Company, Milwaukee. W is. Secretary--HOWARD M. HUNTINGTON*. Work? Safety Supervisor, Tractor WcrC International Han*ester Company, Chicago, III. Program Chairman--GILBERT A. SNYDER, Supervisor, Safety and Sanitation. Ail:Chalmers Manufacturing Company, LaPorte Works. LaPorte, Ind. Staj fiefresentatrve--HOWARD H. WARZYN, National Safety Council, Chicago, I" Engineering Methods & Procedures Committee--EDGAR O. PRANGE (Oiairmar. Safety Director, Bendix Products Division, Bendix Aviation Corporation, South Ber.; Ind.; VERNE AYLING, Safety Director, Pontiac Motor Division, General Meter: Corporation, Pontiac, Mtch.; MERT L. CARPENTER, Supervisor of Safety. Piar.: Protection and Recreation, General Motors Technical Center, General Motors Corpora tion, Detroit. Mich.; RALPH M. COE, Safety Director, Goodman Manufacturer Company, Chicago. 111.; ROBERT COLLIE, Safety Engineer, Ford Motor Compaq. Dearborn. Mich.; "CHARLES A. DeMOXGE, Safety Director. Kelsey-Haycs WVA Company. Detroit, Mich.; WALTER HAAG, Safety Supervisor, Send, Inc., Evar.?vjllc, Ind.; GEO. E. HUMPHREY, Safety Director, Cadillac Motor Car Diviskr. General Motors Corporation, Detroit, Mich.; "DAVID T. MOULD, Safety Director. General Motors Corporation, Detroit, Mich.; EDWARD D. RAHDE, Supervisor c: Safety, Westinghouse Air Brake Co., WUmerding, Pa.; WILLIAM S. SMITH, Safety Director, Ford Motor Company, Dearborn, Mich.; GILBERT F. TYLER. Ford Instru ment Company, Division of the Sperry Corp., Long Island City, N. \ . Education and Training Committee--W. C BARBER (Chairman), Asst. Director of Eng:neering. Michigan Mutual Liability Company, Detroit, Mich.; S. B. HOPPING, Am. 'Mgr.--Safety and Claims, American Car and Foundry Co., New York, N. Y.; JOHN E. KANE, Supervisor of Safety, Temstedt Division, General Motors Corporaiirr. Trenion Plant, Trenton, X. J.; WILLARD A. KERR. Associate Professor, lllinoii Institute of Technology, Chicago, I1L; TRUMAN L. KING, Personnel Rdations Mgr.. Wagner Electric Corporation, St. Louts. Mo.; PAUL KRAMOS, Otiei Plant Sate::Engineer, Butler Manufacturing Co., Kansas City, Mo.; F. B. McXAMEE, SatV.* Director, Clayton & Lambert Mfg. Company, Louisville, Ky.; "J. E MOORE, Corporals Service, Inc., Detroit, Mich.; O. J. PICKEL. Safety Supervisor, Wagner Electric CojtSt. Louis. Mo.: WOODROW W. WILSON, Safety Director, Packard Motor Car 18 Company. Detroit, Mich.; CLARK WOODWARD. Director of Safely, A. O. SMITH Corporation, Milwaukee, Wis.; FRED G. YELTOX, Director of Safety, Delco-Reny Division, General Motors Corporation, Anderson, Ini Health Maintenance Committee--WILLIAM G. HAZARD (Chairman). Industrial Rda tions Division. Owens-Illinois Glass Company, Toledo, Ohio; O. C. BOILEAU, Man ager--Safety & Heallh Section, Radio Corporation of America, RCA Victor Division, Camden, N. !.; HARRY B. BURR, Business Manager, Medical Administrative Depart ment, Chrysler Corporation, Detroit. Mich.; LESTER V. CRALLEY, Industrial Hvpenist. Aluminum Company of America, Pittsburgh, Pa.; "GEO. F. XUERXBERGER. Safety Engineer, A. B. Dick Company, Chicago, 111.; FRANK A. PATTY, Head, Industrial Hygiene Department. Research Laboratories Division, General Motors Cor poration, Detroit, Mich.; J. C. RADCLIFFE, Supervisor--Industrial Health Unit, Medical Section, Ford Motor Company. Dearborn, Mich.; H. W. SPE1CHER, Indus trial Hygiene Engineer. Westinghouse Electric Corporation, East Pittsburgh, Pa. Membership Committee--WILLIAM E GRUBER (Chairman), Manager, Safety Engr. Dept., Standard Accident Insurance Cr... I>etroit. Mich.; WARD H. ANDREW'S, Safety Supervisor. J. I. Case Company. Bettendorf. Iowa; FRANK A. FISKE, Safety Director. The Brewcr-Titchencr Corporation. Cortland. X. Y.; *F. H. HUMPHREYS, Manager. Property Department. American Car and Foundry Co.. New York, X. Y.; B. I. POVOLNY. Personnel Sujcvisor. Detroit Diesel Engine Division, General Motors Corporation. Wayne, Mich.; GERALD C. SQUIER. Asst. Safety Engineer. Chrysler Division, Chrysler Corporation. Detroit. Mich.: "J. W. YOUNG. International Harvester Cotnpam. C1:io:.i;\ Hi 'Committee Adviv.r and Past General Chairman Automotive caul Machine Shop Industries Checking Performance oi Process Exhaust Systems By W. G. HAZARD ^ DirM Industrial Hygiene, Owens-Illinois Glass Co., Toledo, Obio Checking Performance of Process Exhaust Systems 5 FORM 1--Safety Engineer's Inspection Report Condition of hood and branch (Battered? removed? plugged? repair?) Static press. (inches water) Checked Some two-and-a-half years ago the Health Afaiatenance Committee of this section un dertook to develop a data sheet on the main tenance of local exhaust systems. The jcb is now about completed, with the help of the whole committee, and your program chair man has asked that we give you a preview of it. Purpose The purpose of the data sheet is some what different from that of most articles that have appeared on exhaust systems. What's made this possible has been the timely appearance m the last few years of outstanding books on the technical design of exhaust systems. Among these publications are: 1. Manual of Industrial Ventilation (1952) American Conference of Governmental Industrial Hygienists 2. Industrial Health Engineering (1947) A. D. Brandt 3. Industrial Hygiene and Toxicology (1948) Frank A_ Patty, Ed. (Chapter 10-- Ventilation, by \V. X. Witheridge) 4. Exhaust Hoods (1952) I. M. DallaValle 5. Accident Prevention Manual (1951) National Safety Council (Chapter 21 --Industrial Health Engineering) 6. Ventilation W. C. L. Hemeon 7. Industrial Dusts (2d edition) Phillip Drinker and T. F. Hatch To be published 8. Design data published by numerous man ufacturers. such as American Blower Corporation, American Air Filter Com pany, Buffalo Forge Company, Westinghouse, and others. The first design and technical mainte nance of exhaust systems falls in the lap of the plant maintenance or engineering de- pailment, and the above books handle these aspects thoroughly. Little has been written however, directly for the safety engineer. What are his responsibilities? What is his role, when the engineering phases are handled by the plant engineer? This data sheet is written for the safety ragineer. It does not cover detailed design, instrumentation or maintenance. It contains only such background principles, and com ments on popular fallacies, as are needed for, the safety man to *ork profitably with the engineer and department supervisor. What Can Safety Engineer Do About Exhaust Systems? 1. Air samples; Exhaust systems that arc meant to control a health hazard succeed or fail according to how well they keep the air contamination in the workroom below dan gerous levels. Usually this can be deter mined only by air samples and analyses that actually measure the amount of the harmful agent in the air. Method used varies accord ing to whether the material is silica dust, or other toxic dust; vapor, as from a solvent or degreaser; fume, as from wdding; gas: or even hot air--for the latter can be classed as a contaminant, and exhausted to the out doors. When the plant has no full-time industrial hygienist, as most plants do not, the safety engineer should arrange for these tests. The}* are his responsibility rather than that of the plant engineering department. Such tests are not needed when the con taminant is not harmful, as with wood dust lime, coal, and other nontoxic materials. 2. Plan: For existing exhaust systems the safety engineer should get a simple sketch of the layout. 1 his need not be a working blueprint or even to scale. An example of a simple line drawing is given in the data sheet All that needs to be shown is the order in which brandies come off the main ducts, diameters of ail ducts, arrangement of fan and collector, size of fan and motor, and if possible, overall rate of air flow* and static pressure as specified by the designer of the system. Filter resistance (J)-(H) 3.0 Material collected Hours of Interval between ?ince last check_______________ ibs. operation-------------------- rcg. shakings-------- t.'omments of men, and Your comments (use back, if necessary*) :------------------- _ hrs. Test holes: In each branch, near the hoods, at the collector intake, and at the fan intake, the safety engineer should have simple test holes, about A" in diameter, drilled. These should be numbered serially with ;atn: or tags, and on his sketch of the piping he should mark the approximate lo cation of each hole, with its number. 4. Portoble U-tube: He should then equip imself with a U-tube or water manometer. After connecting one leg of the manometer :o a piece of rubber tubing, he can hold the :her end of the tubing over each test hole :r. order and measure the static pressure or uction. If the system is new, he should sec that the plant engineering department `'balances" the air flow from each branch--which means that the correct amount of air flow, as called for by the designer, is passing through each branch. If the contaminant is a health haz ard. air samples, taken after balancing the system, will tell the safety engineer whether control of the air pollution has in fact been established. From then on, assuming no ranges are made in the hoods, piping or process, he can be assured that the equipment continuing to work right, if rechecks at the test holes give him the same static pres sure readings as the initial ones. Recheeks with the U-tube should be made regularly, probably at intervals of not over a month. He should Iiave a mimeographed form to record permanently the current readings, so they can be compared with the initial readings. These suction rechecks make it unnecessary to take frequent air samples. Certain other defects, which can be checked merely by looking should be noted: bent or battered hoods, new* branches that may have been added, changes in the process, etc. 5. Meaning of U-tube readings: Knowing what the static pressures were when the system was properly balanced, changes from these values show if and where trouble develops. For example: The increased reading in the first branch, with other readings remaining normal, shows something is plugging that branch between the test hole and hood. A decreased reading in the branch would mean there is some obstruction farther up the branch, that is, between the test hole and the main duct or header. Decreased readings in several branches and near normal readings would result if the header was partially plugged in branches nearer the dust collector when the header leading to the collector becomes plugged. There will be inemsed readings on both sides of the collector. A partly plugged arrester would result in a decreased reading upstream and an in creased reading downstream. Decreased fan capacity* due to slipping fan belt, dirty* or worn blades, disjointed pipe between fan and arrester, or an open clean out door would give the decreased suction readings throughout the system. Thus relative changes in readings at dif ferent test holes can be used to track down the trouble. Certain absolute values are important too. For example, although suction at a hood is 6 Automotive and Machine Shop Industries Cheeking Performance of Process Exhaust Systems 7 no guarantee tliat the hood will control the contaminant, still some stale codes do re quire that a certain minimum negative pres sure be present, often 2" water gauge. The safety engineer should ha'-e a copy oi codes applying to exhaust systems (usually admin istered by the state labor department). He should sec that their suction requirements are met. 6. Repair orders: When maintenance work U needed, the safety engineer should sec that the proper work orders are processed, following whatever is his plant's usual pro cedure for this. Role of Plant Engineer Some may think monthly inspections of exhaust system performance, including meas uring the static pressure, are more the re sponsibility of the plant engineer than of the safety engineer. Experience has shown, however, that unless the safety man takes this equipment under his wing, it will often be neglected. This happens for two reasons: first, most local exhaust systems are not production equipment; if they were they would be assured of regular care. Second, while they are a collection of sheet metal, fans, motors and other mechanical devices, which are engineering in nature, their basic purpose is to improve the comfort or safe guard the health o: tite People on the job. This aspect is definitely the worry of the safety man. and only indirectly of the plant engineer. The fact is. a system can be mechanically OK. m tint the piping is tight and well sup ported, the fan is properly chosen, the bear ings are well greased, the motor is not ,verIoaded. etc., and yet the system is a failure. lt*$ a failure because it does not succeed in making the air safe which the men breathe. This is the "proof of the pudding"--and the safety engineer (or in dustrial hygienist) is in the best position, through his air samples and other tests, to see tliat the equipment does really clean up the workroom air. There. are of course, certain inspections that the plant engineer should make. Just as he would with any other moving machinery* On regular schedule he must lubricate the fan and motors, check rapping mechanism of the filter, inspect the latter for leaky bags, check any motor-driven dampers, etc. --and repair them, when necessary. Facts and Fallacies for Safety Engineer , to Remember ; Production people and even engineers hav 1 ' misconceptions sometimes, for which safer. J: engineers should be cm guard. Here arc i ll few: ; 1. Performance Guarantee: Since ti c safety engineer is concerned with imw:'; _ work conditions, he should do all he can : see that the purdiasing department, wher placing an order for a local exhaust systcr*. ji ha; a performance guarantee written in. . 2. Adding Hoods: Many a first-class ex haust system is made ineffective by the hit-or-miss adding of new hoods in later years. Be sure the plant engineer checks th? system to see it will liandle the extra kcvl ; 3. Makeup Air: Getting makeup air. ter-pcred in winter, into a room is sometime? more perplexing problem titan the exhauv system itself. Be sure this problem is solve: beforehand. ! : : Yet, this mixture is only 0.17 per cent heav ier than air, even though pure benzene vapor three times heavier than air. Thus the ratio of weight of air to weight of the l<nzene-air mixture is only 100 to 100.17. There could never be any sinking or strati fying of this 1000 ppm mixture. A side or 1-ack hood would be just as effective as a J.nvndratt hood. 7. Fallacy of "Sucking" the C'<mfawinoil Jt.io Hood: Because people can feel air : \m-.ng out oi an air line some feet away :rc?n the end oi the pipe, they think that dust-laden air can be sucked into an exhau-t h.-od irom several feet away. This is not true. Air can be sucked only one-thirtieth oi the distance it can be blown. In exhausting, the air velocity has fallen to 10 per cent at a distance of only one pijw diameter out from the end of-the pipe; in bl.ou-~.ng, this <4. Explain to Employees: The man <:. the job must understand the reasons for ths exhaust system, and how to operate it. it is to give him full protection. The safe:; engineer can assist the supervisor in givi:.. this explanation. Better vet. consult the mtt*eforc the final design is agreed on--so then will be the least amount of interference wi:':. his work from hoods, enclosures, etc. } i " ; ' : 5. Smoke Tubes: One of the bandit*: gadgets the safety engineer can have is smoke tube (available commercially) to show the path of air currents as they enter t::*. hoods. With it he can often convince tr.t operator of the importance of baffles, close ness of hood io dust source, etc. j ! ? : . 6. Fallacy of Heavy I'cpor: Bccau-< some vapors like benzol, trichloreihylcm. carton tetrachloride, ami the like are heavier than air. many people think downdraft ven tilation or hoods at floor level are a mu*: The fallacy is that vapors coming from .< process do not persist for long in an und:lutcd state. They are soon mixed with air. by random wind and convection current? Once mixed, they don't normally settle o:r to form a heavy, concentrated layer at trt floor. . , A concentration of 1000 pjim of Ixmze::: is 25 times the maximum allowable limit. bliealih standards. It is far more concentrate: than would be permitted in any workroom: 10 per cent figure is reached some 30 diam eters out from the end of the pipe. Suppose for example, we have a six-inch pipe suck ing air in so the pipe velocity is 4000 feet per minute Only six inches out from the "sucking** end of the pipe the velocity will be a mere 400 feet per minute--hardly enough to feci. But at the blowing end. this 40"J lpm velocity will not l>e reached until you go 30 diameters, or 15 feet away from the pipe end. This misunderstanding also crops up when installing propeller ians in walls or windows to provide ventilation. Such fans are incap able of withdrawing air directly from any operation in the center of the rocm, or in fact, from any 3rea more than a foot or two from the fan. Beyond that they ac: only by diluting the room air by drawing in masses of makeup air through doors and windows.