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FILE NAME State of the Art Literature SAL DATE 1938 DOC SAL028 DOCUMENT DESCRIPTION Govt Public Health Bulletin - the Asbestos Textile Industry A Study of Asbestosis in pf Vite mal) : megs . ast La - . ai: 2 ~ ealtoa at : ke nc BR _ &\t wt? to . Pet) ac . ? . * ag oe Oe pe 4. Gt a SeerBULLETIN po 3G = PUBLIC a PUBLIC . 5 a = a" HEALTH : . . pa OFre . oe? co a HEALTH BULLETIN Be ra we \ 7 - cy se 3: Seee veoye < ota . Ny a rt. ha oe . . . oe Prey oe tee tie +. . . , a ASBESTOSSIa S EeEsS et ote a es ate ce~s~ etsew -g e rion ry . Cr we * 4 oH ~~ . -~ 2 . Se! wae yn a ag . A been I) ees THE ASBESTOS TEXTILIEesN INDUSTRY 2 ene ~ ory Me of eee agence Retr em PUBLIC TREASURYDEPARTMENTaati SERVICE we } PUBLIC HEALTH SERVICE SERVICEnurs x TH+E4 WASHINGTON ae _ : . . : oan . . an) . ; yy ee re Oty o- wor ew Ag oe Ge von gts NR. tee . fee om. . . *s Fae Me, eee ~. biteot te nos . ~ . ay ee ba _ aa : - Ry 7 F Li ae ~ ae os t 110 -? e af? et ares : y: . - . *, aid si ..! U. S. TREASURY DEPARTMENT ~~" up 3 PUBLIC HEALTH SERVICE *" Public Health Bulletin No. 241 Angost 1938 A STUDY OF ASBESTOSIS IN THE ASBESTOS TEXTILE INDUSTRY By WALDEMAR ( DREESSEN Passed Assistant Surgeon 1. M. DALLAVALLE Passed Assistant Sanitary Engineer THOMAS I. EDWARDS Technical Editor J. W. MILLER Pathologist R. R. SAYERS Senior Surgeon With the assistance of H. F. EASOM M. D Director M. F. TRICE Engineer Division of Industrial Hygiene North Carolina State Board of Health , teqeS From the Division of Industrial Hygiene National Institute of Health _ eeum PREPARED BY DIRECTION OF THE SURGEON GENERAL UNITED STATES GOVERNMENT GOVERNMENT PRINTING OFFICE WASHINGTON 1138 . And all tee oe -- - ITIAIR^ ntITIAIR^ nt of IbwUAPRIL . em "b eee 6 ... ee ee ew Item Sf wee i NL wi ORGANIZATION OF THE NATIONAL INSTITUTE OF HEALTH Thomas Pannan Surgeon General United States Public Houli Service L. R. Tugarson Assistant Surgeon firnerul Director National Institut ni II Division of Biulogies Contral Senior Sure W. T. Harmisos Division of Chemistry Pruf C. S. Hudson Division Lurison Dirision of Infectious Diseases of Industrial Hygiene of Pathology Surg R. Senior Surg Senior Sura D. Lillie R. E. R. Dyen SAYERS Division of Pharmacology Pharmacologist Directur Cant Voegtlis Division of Public Henuh Methods Surg J. W. MouNTIN Dirixion of Zoology Chief benior Zoologist Willand { Wright National Cancer Institute Pharmacologist Director Carl Voegtlin National Adrianry Cancer Excentive Director Dr. Ludvig Hertoen Hertoen 1813 o Abst ..r 0.a.c . lt l, a 1X Introdu eeceti eoe ne 1 Objectives of the study The working econ environment rere Cert w e voce Methods and instruments used in the study of '' e '. .3 e eee cece ewencee the working environment Pree eee . ee . eee tee mwmoecesnnnnne wees The ee Ce ers 33 manufacture of asbestos textiles Preparation meee eee ee ee eee eee ees 33 q . eeeee Carding eee, 2... eeeeeee eee ee eee eee e ae 3 . Spinning .. been w w e ec wen ce ese ene Occ e eee ne te eeeee eee o Winding twisting and spooling o.oo. eee eee eee we eee Wearing . see ence eee eee e tee eee . sec eeeee 11 Brake manufacture been ec 13 British esac en ences manufacturing methods sateen wwe ccesacses. 15 Occupational analysis and a description of the chief occupations 0. Preparations . 18 4.200. se eae we eee eee eee eee ee ee eee 1 Carding cece eee see cess eae e c eee cece ee eee e eee ee 1 Spinner . eee eww eeee taeeee eee eee esse. se eeee ese " Spooling twisting winding and treating |. ence ere ecnce 18 Cloth tape and weaving eee enee Oc e ys All ne cen eee iee other oo. 2. eceee Results study Dust of the engineering Peder eee m weer ence 19 aee. ae studies SO 10 Nature of dust found in asbestos textile factories Composition eee eee ee 10 Toe oon 19 eee e enc emecec ees 19 Particle 23 size Dust concentration in different occupations | veces a5 Preparation 200s ecec eee eeee ee ee cee ncecec ensue... 2, Carding .0cceeeeeneeeeneene esc cewccce 2... 0 eeweenrerescorceees cceceececcuse,. ences. Qh 2: .... twisting and winding 0.0.00. oie weaving oes cee sees cnacccane, a panel weaving wick and brake rope and braid working ae, finishing Le wasceecec. wo weaving trakoshanel eee 0.02. notation eeeee . 381 in ooo] teen cece ec eens cee. Previous Previous dust vXjmmaTO vXjmmaTO eee ee ee ., Interpretation of dust counts ae Po ee w count dust Then of asbestos ee ooo. eww eee. ween, wees. Preparation department Spinning Spooling Broadcloth Tape Cord Miscellaneous to 31 fe AA aan Wilbewing . Piling . Picking ee eee ele. Leeceee.. Carding hi Se ' oer oe eee oe . . rn aeeee eee. oe cee . , Spending and twisting ccs... Winding sek . ae _ wees Leeee. Losjactive . ee Summary of the study ee of the ee ee working a environment ad A .. ae OY ve fit 11. employees Statistical description of . CCC R ame en em mm menace neaveveacans Occupational histories Comparison Medical study with other eee e ec caceccneene industrial workers , ee ee cnc ne, a 2 2 eee eee eu eee. ee os... 0c. oo Procedure Past medical history asbestosis wee ewe ee ce cc nwece Symptoms of asbestosis ray findings 00.00. wee eee teen eene eee ese ee aces mete wen weet ener nce ansceetecuewe Lung markings eee neeeee eeeeeee. ae ccwwecseee findings Diaphragm ed ee Physical ee Ce ee Chest cere expansion .. Meme ener eeesene ens .s eee ee Respiratory 2.60.8. weeee an ee senees Clubbing of fingers and curving of nails , ee ee ee Heart defects eek LaborAastboersytoF s indings cae e cornia eae. eels te mw ee eeee tee e ee ee eeeee sseee ee ec emcee eee se eeaeees The Asbestosis bodies . ee eee eee Results of tests on urine wees eee eee eee eee os. diagnosis of asbestosis ele ol eee e eee er ace -- cee Occupational history 0.020. a eeeee abe e cece cence cele ase ray 0.2.02... findings ccc ee Classification field markings of eee Pomme cece eee oe 00.0... cole. vee Symptoms 0000008. eeeeeee tec eee Representative case histories eee es cece eas Incidence of asbestosis , re .. asbestos Threshold concentration of asbestos Incidence of asbestosis in different occupations Asbestosis in Great Britain and the United States wecceacese . senswnveeveaae Pathological findings in asbestosis .. TO Ow Meme meme wm ad nme Gross 2 eee cannon ence cee nee e nrvacacvaane cece een ece ee, Microsacopppieeaa rancpe pearance Selected autopsy reports ere cesew ewes ences eee eee ewesccnene eee. ... 2.0... Acknowledgments Summary of medical eeee sec ece sec eece ll, we Oe eee rewmenaare findings LTTE Te ee Annotated bibliography . ITLL . . Te Te eee gun ILLUSTRATIONS practice 1. Vacuum cleaner bag arrangement for collecting 2. Flow shot of American suspended dust samples samples 3. Mill for crushing asbestos ee tence ees filler ce 4. Div oj^/meror willower fixite exhaust as oo ee. 6. Exhausted carding machines 6. Spinning mindes .. eeee aeee, eee sees eeee ee een 7. Twisting machines ce a eee eee ee eee cacne ~. Exhausted brander eee 9. Rope making machine cee eae tee eee eee eee eee lee. . 11. 11. HrisudelatHrhisudelath weaving demam o. oe sees . . wee Brake sections e Lerreds -- . weastrat weastrat bean shining three of the eee ee six sectiosenctisons wild wargane wargane i re .... 12. 11. Flow short of British Virus appearance of primitive suspended eee celle. dust Be vceecee ee. device see bg 1 Voce a a3 +6 15 15 10 50 oa a4 6] 62 1.3 % Abi Crore as we 49 v4 v4 oe) 75 75 84 at H 05 001 TOE 11 11 11 VII Figure 14. Microscopic appearance of suspended dust collected with vacuum cleaner device at 200 ^ ..... Powe ccenseaneene wweeareee ..... cecece Exhausted piling bins 15. oennen--.-- wre cee e cence 16. Exhaust ventilation used for piling operations British practice 2. 17. Schematic drawing of exhaust system used with picker machine 15. Vertical exhaust ventilation applied to an unenclosed primary carding mac ..h .. i can tee applied ee eee ee cece eww mec mnncn nee 19. 2 21. Totally enclosed exhausted prunary carding machine . weceswcwwmae Elevation and plan for spouting Exhausted spooling frame exhaust systemi ... Por meeesceserawes cece ewe nec c nec ns a cacnewce 22. 23. 24. Exhausted twisting franie loom Exhausted broadcloth Detail of exhausted lunin altown PM Tw e ee eR nen cee cee in figure 23 meme meres cece eee ameremwnecsces 25. Detail of exhaust used on British type loeo e cee eem e cece e 26. Exhausted brushing and inspection table 27. Form used for recording occupational history . ro 2 rs 24. Form used for recording past and present medical history 2.002. Percentage of persons classi^-ed by dust exposure who had certatis disorders .... cacancnedece eee een eee c ent acn cca wee seee 30. Pereen ige of persons classified by lung markings who had certami disorders 22. Oe a 31. Form used for recording ray findings .. 32. Schonie used in classifying ray markings Coen e ewww scenes 33. Percentage of males classified by age who had certain fieid markings . glass ee ee ed De eam mmr er ern cen enc cenae 34. Relation of ground lung markings to length of employment 35. Relation of ground lung markings to dust 36. Incidence of exposure ground lung markings in relation to length of concentration 37. 38. represented employment and dust Relation of diaphragmatic fixation diaphragmatie fixation are Form used for recording to 6. ek eee ewe eee en ene dust exposure Three stages of . eR ew nw awn resavacwmace physical findings 39. Photomicrographs of asbestosis bodies found in sp0 utui0 n . Enla0 rged 530 times except E which is enlarred 310 times A scale ruled in units of 50 inicrons has been drawn beside each asbestomis 39a Asiuntos cum on thutub of year nid man body employed 4 years the card room of an asbestos textile ...... cee factory MI Purtims of clust ray films which illustrate the succemc ivee ell iane ges brought about by continued inhalation of asbestos ilust 1-51 Chest ray films illustrativ^individual esse histones . eeee 32. Photomicrographs of lung sctions showing the presence of numbllar fibrosis and emphysema in a ilien ie lung and diffuse fibrous and 3.1 eimply sema in an ashestatie lung A section of a mirinal hing is stuun for empar~-s~-n Magnincation 10 Astmistusie luads . i rs wacee cece in avvolesviar connective Tissue Practicalls nich 51. acompanist 7031 Kilirosis in this ann Case 11-21 Magnitration 1,000 Mechcal Museum No. 82.255 , UN Bee ccc e eee ccc eee i Aslasten Aslasten 5 Inalies ie accompanist by giant erlis man man area of tilensest listig tissen Case 11-21 Maguntication 7031 Army Metical Mus seman No. 32.255 32.255 35. 35. Case 21 interjobar Right pleura ry oh rs lung Markostly Tucketed pleura wille fumman ask These thrusts tags over mutite surfais se 22 34 35 3 358 358 358 358 358 358 446 446 446 446446 % % $ Gime VIII Figure 36. Case 21 Left lung Pleura niuch thickened Fewer Abrons ail- Page hesions than were noted un the right lung . 37. Case 21 Section of night lung Advanced ashesTUGLE Distended 103 bronchi and air spaces at both apex and base Diffuse ^brosis throughout lung substance and thickened pleura . ck. .- 10+ 38. Case 21 Section of left lung Distended bronchi and air spares emphysenistous spex Rather uniformly distributed fibrous and areas throughout rest of lung Pe ewee tem eee eweesecewancesee ray pleural 39. Chest of case 23 15 months before death 60. Case 23 Right lung Entire surface covered ee by dense fibrous tags . WOT RCO ROM Hee Ce mm fibrous Dn smevewemtererenesne 61. Case 23 Left lung Very few fine fibrous tags are sinted on the Irg 1 07 ids Moderately pleura ... mere eee ev emesmwnvecas Se Moderately ee e e k e 62. Case 23 Section of right lung advanced asbeslasia Fibrous areas and emphyseina uniformly distributed throughout the 300 lung substanice .. emer ee Ben wmeveeseesmecnvaseance Weeereeroevocone 63. Case 23 Section of left lung Shows less involvement than right lung .. ee 2 ee wveeeree 61. Case 25 Chest rays taken 13 months and month before deatl~- Part of the difference between the two roentgenograins is due to a difference in ray technique . Ea.rly eedmwwmmeeramwerercrereeccnse 65. Case 25 Section of right line Early asbesto Uniform alsoo " 113 tribution of fibrous areas throughout lung substance ... eres 114 fe . ABSTRACT stablished Asbestosis a lung disease caused by continued inhalation ushestas dust was the principal physical defect found of examination of 541 men and on medical women employed or recently employed in three asbestos textile factories dust The primary effect of asbestus seems to be initiation of fiue interstitial which was not observed to pulmonary fibrosis fibrosis was observed in progress as far as the nodular stige This asbestos workers mortem examinations of three former During life Jung fibrosis can be detected examination The by XN more important symptoms of asbestosis are sgtrersesaikveed dyspnoea variable cough which sometimes raises hipnrdo-- sputum and loss of weight dust in asbestos textile factories The processes that produce for dust control were studied and recommendations are incorporated in this report 242 were made in all parts of these factories Enough dust counts pisure of each worker enn be estimated so that the dust ex- in different The percentage of persons any of its syocmcputpoamtisonvaalrigerdouwpisthwthhoe were affected by asbestosis or which they were subjected and avernge dust with concentration tu their length of employment The only cases of asbestosis three in number found below 5 particles per cubic foot were diagnwed us doubtful million enses occurred at higher concentrations It that if asbestos dust appears from these data concentrations in the air breaths are kept below below this limit new cases of asbestosis would not appear II \ )Payee A STUDY OF ASBESTOSIS IN THE ASBESTOS TEXTILE INDUSTRY INTRODUCTION - Several important properties of asbestos have led to its widespread use in industry As everyone knows it is nonconibustible and an excellent insulator against heat and electricity Fewer people seem to be aware that its fibers are sufficiently long and flexible to be carded spun and woven like wool fax or cotton Utilizing these properties el asbestos industries have been developed in this country which employed more than 6.000 men and women in slightly more than 60 establishments in 1935 , Another property of asbestos lins been discovered more recently When asbestos dust is inhaled daily year in and year out a lung sisease termed asbestosis may develop In many respects asbestosis resembles silicosis but it differs from silicosis in several important particulars which will be discussed in the medical section of this report The first record of a case of asbestosis seems to have been made by Montague Murray in 1900. The first complete description of the disease and of the curious bodies seen in lung tissue and sputum appeared in 1927 when Cooke 9 and McDonald 22 reported two cases of asbestosis and listed their reasons for believing that asbestosis bodies originate from asbestos fibers that reach the lungs lication of their papers aroused general interest in the The pub- subject and numerous papers appeared soon afterward Hoffman 46 appears to have been the first Americnu to call attention to the magnitude of the asbestosis problem In 1918 he reported that 13 deaths from asbestosis had necurred sunong asbestos textile workers and about the satu^' time Pancoast Miller and Landis 22 9 9 reportal on 17 cases of asbestosis Mill's 26 paper was the first pathological asbestosis published in the United United States and in the report on same year 1930 Lynch and Smith 18 reported on asbestosis bodies found in the sputum of asbestos workers Because several satisfactory literature reviews of asbestosis have appeared in recent years there seems to be no need to eq plete literature review in this present a comis report Some of the mure useful litera- ture reviews have been listed Merewether 27 review in the annotated bibliography tes emphasis emphasis is land on the relation relation of arstistuses arstistuses CS iy 2 to working conditions The clinical treated Gloyne's 16 discussion aspects of of the subject are well particularly helpful Middleton's the pathology of asbestosis is coniosis contain a section 47 Milroy lectures on pneumno- the literature on asbestosis Egbert 13 has suminar~z~ j reports on 28 fatal cases of asbestosis monary tuberculosis was present in 6 instances of the Active pui- the fatal outcome was total 25 cases instnoces primarily the result of tuberculosis in 3 OBJECTIVES OF THE STUDY health Health The Public Health Service Health and the Industrial was requested by the State Board of Commission adininistrator of the Work- men's Compensation Act of North Carolina to assist them in an engineering and medical study of health hazards in making textile industry The objectives of this the ashestos make a medical study of the effects study were threefold 1 Te of continued inhalation of ashestos dust on the human body 2 to identify the processes that create dust and to manufacturing necessary equipment that will recommend practices and when and find reduce the dust exposure of workers what concentration of asbestos dust can be without injury tolerated __ ' The represents one of the arst Public Health service and a state uses of Social Security Security health departiment funds for a cupperitive project cirried en the a, co . Sowa NN THE WORKING ENVIRONMENT METHODS AND INSTRUMENTS USED THE STUDY OF THE WORKING ENVIRONMENT e The evaluation of the working environment and its relation to the health of workers forms the basis of all field investigations conducted by the Division of Industrial Hygiene The procedure followed by this Division is described in Public Health Bulletin No. 217 21 Therefore only a brief discussion of the subject is presented in this report The study of an occupational dust problem begins with a preliminary survey designed to obtain data on all the occupations in a given plant It includes the number of workers employed in each occupation and the materials used in each process The survey also reveals the number of workers exposed : a given hazard Following the preliminary survey an evaluation of the occupational environment is made In the dusty trades this includes a determination of the amount of dust present in the air its composition and particle size and the measurement of the effectiveness of exhaust systems where they are used control dust hazards The latter in this instance involved airflow measurements of several exhaust systems by means of a pitot static tube The effectiveness of these systems was determined dust counts by THE MANUFACTURE OF ASBESTOS TEXTILES Approximately is 90 percent of the asbestos used in these plants obtained from Canada The remaining 10 perrent Atrruilzioanna or South Africa and infrequently from Russiacnomaensd fAurso-m sources Much of the machinery that is employed for the manufacture of oufsbestos textiles is identical with the machinery used for the production cotton and woolen goods Crude usbestos fiber is sent first to the preparation department and then in the onder namel to the machines spinning frames winding bobbins twisting maccahridniensg dsepovoilciensg frames and finally to the looms and miscellaneous fabricating The four plants investigated in the present study fall naturally into two classifications Two plants convert crude asbestos and raw cotton into asbestos yarn mid woven goods but do not prepare the ia 4 products for the ultimate consumer The other two plants purchase both asbestos yam and unfinished woven asbestos tape These establishments weave brake bands and convert their own woven product as well as purchased material into finished goods The practices followed in the plants studied are schematically presented in li the flow sheet shown a3 in figure 2 ik PREPARATION Crushing The first step in the modulacture asbestos textiles is the crushing of the ernde stock in mili ing machine This is accomplished by large iron rollers which re- volve in strci pan in which the crude ma- terial is placed See fig 3. This operation separates the fibers and loosens the impur- ities that survived the cobbing of the ore at the mines The crush- ing operation does not produce much dust the filers being disins tegrated by a mashing and twisting action | Most cru oredmue st be crushed for 20 minutes although in some cases it may be satisfactorily disinte grated in 5 minan FIGURE 1 -VACUUM CLEARER BAG ARRANGEMENT FOR COLLECTING SUSPENDED DUST SAMPLES crushing the asbestos is replaced by hund in to the willower The crushed astrestes has ance matted Following appear- Following Following the the bags for delivery 11'illuring The willowing willowing or opening of the usbestos is cleaning operation The essentially willower beats and shreds the matted S FLOW SHEET AMERICAN PRACTICE Crate apes . 4 Creme wit! aewr (Rae stes oF uaery creenags 4 Ree cetvee 4 frecer frecer | . 1 reume wohetsinag . Petting ne . t Ms 1 the the : Secmer Scree 1t i i ' . the eueessomiiy 5 v SAVE 1199 07 261. 261. bot . wuner? coreumnng { . OrPecere eenas te ree lt Serer fiwes wen ep, > wet an orwee premaets - etasresse | e Se me , : ry - | . COMrOe s52437CS ater == ^' LIG16 WRTH Tasouns Anw of a ins Lr IG16 WRTH WRTH of A Gat)ried Co.ioeten . 100 ry Secemtary Planer t 100 A dan Tis %...0wer :: ar stfees Rotenes Pessing | 90 BOR BOR BOR ** PAdOee Avgri Avgri Avgri Lima | w en meme Based thera Ging arr arr Pes ant Pessant * Relea ( La as Shark firm O18 La come come to weass Mnalestaers en p ean. 1268330 Sei! ve Cottne Corte Os feo le treee | Om Seetol pruny bar @ y at's. -wvwmece g PUTAGE coo card peeing Cer e.oesries, ue- Pasttiom eas aecasnr, Wet wag mma ning Ome: Te aw Chepregration tite Ohiner na Ovens, or we paste songmeme| mee } Lat ume * tag * cnet TAT Gebseus ng | Garnet FIGURE ? -Flow Sweet OF AMERICAN AMERICAN PR^ C 7 of cotton used depends upon the quality of the willowed asbest fibers used As rule from 5 to 15 percent by weight of all the asbetos textiles produced in this country is cotton Piling the plants studied the mixing is accomplished in tw steps the first consisting of placing the cotton and asbestos in alter nate layers in a pile upon the floor and the second step of feeding th mixture into a picker machine The batch making or the placing o the cotton and asbestos is known as piling It is productive of muel dust since it is necessary to spread out both the cotton and asbesto into uniform layers which involves the use of a rake and muci trampling of the materials Picking the mixture is minde it is lifted into the breast high hopper of the picker machine The material emptied into the Figung 4 OPENER OR WILLOWER NOTE EXHAUST hopper displaces air in the hopper which causes dust and fibers to escape upward into the face of the worker In addition the cylinder and accessory rollers of the picker machine operate at a high speed and much fine material escapes from the many small openings in the frame The dust that is fanned out of the machine together with that produced in the feeding operation makes the pickerman's eveus pation comparatively dusty In some plants two pickers are opere ated in series and in others only one through which the material may be passed several times In either ease the picker discharges directly or by pneumatic duct into a collector bin Where only one machine is available however the pickerman most move the matenad by pitchfork from the collector bin to the thour of the picket town fest its recirculation through the picker At one of the plants studied there are two pickers operated in series series and connected by pieritnati Re Lee oe a 8 ducts Here the collector bin is also the storage bin In order to prevent the mixed material from accumulating in a steep pile a man is stationed in the stock bin at all times This occupation creates considerable dust since the asbestos mixture is delivered into the bin by overhead duct discharge In order to reduce the dust exposure of the stock man his position is made interchangeable with the pickerman each of whom spends a half of every day in the stock bin and a half day at the picker In the plant having only one picker the mixture is trucked from the collector bin to the storage bin At one of the plants studied exhaust ventilation is provided for the picker machines and the mixed stock storage bins Cil sprays are FIGURE EXHAUSTED CARDING MACHINES frequently used within the picking machines in an attempt to prevent the formation of dust 7, ot CARDING From the storage bins the stock as it is called is hand trucked t the carding machines where it nung be piled upon the floor or fed into the hopper of the breaker cani The cards perform several duties They give the fibers an aidilis tional mixing arrange them in parallel positions und form them into roving The term roving is applied to the strands of parallel tiers that are produced A carding unit consists of two almost identical machines The one through which the isbestos misture pusses dirst is termed the breaker enri and other the finishing cand The machines are quite similar in that a large revolving revolving revolving exlinder with several accessory rollers performs performs the major portion of the wands See fig 5 The carding operation operation is quite similar in that of the me ee we 9 picker the essential difference being that the roller and gylinder sur faces are studded with fine steel bristles rather than large hookSome of the rollers straighten the fibers by combing out the tangles while others doff or remove them from the combing rollers and ti cylinder Aside from these main features the two units differ slightly The breaker card is equipped with a feeding hopper similar to tha used on the picking machine while the finishing card is provided with a device for forming the carded fibers into strands In the plant- studied a system of conveyor lattices transfer the carded fibers from one machine to the other The outside strands of roving are returned sea Figure SPINNING MULES to the picker for reworking The remainder of the roving is wound on long rollers with flanged ends called jack spools The studded cylinders of the carding machines revolve at high speeds and much lint is thrown into the atmosphere The effec produced by the revolving cylinders and wheels is similar to that of a fun and as a result much of the dust remaining on the stock at this point as well as asbestos and cotton fibers is blown into the air Al carding machines studied were provided with exhaust ventilation While practiently all of the roving is spun into yaru some of it is marketed without further processing other than winding on speels oe: into esils In this form it is used for electrical insulation and for conversion into packing for machine beurings APINNING The jack spools containing the roving may be convexed either to the mul^'sp^>mingmachines shown in figure ti ot to the ring spinning frames The spinning on whitever ma^lumeperformed as twistit ^' operation which imparts strength to the strand of fibers by 11.2 .  10 locking or meshing them together The ring spinner twists the roving as it is wound on a spindle while the mule spinner performs the same treatment in two operations first spinning it in 5- or foot lengths and then winding it on spindle The ring spinner makes a yarn that is stronger and better in many respects than that produced on the mule spinner WINDING TWISTING AND SPOOLING The spun yarn is converted into stronger thread in two operations It is taken first to the winding machines where it is transferred from spindles to tubes After being wound on tubes the yarn goes to the twisting machines where the thread from two or more tubes is brought together and twisted into one thread In the twisting operation the thread is frequently strengthened with brass zinc or copper wire or e . Following the Figure 7. TWISTING MACHINE with cotton twine initial twisting operation the yarn ne may return winders for placing on special tubes in which form is marketed Then again it may be conveyed to the cop or twili winders where it is wound into spindles for use in the shuttles of the looms There are a variety of winding operations that prepare the yam in some particular manner for the mrket or for use on certain types of machines Likewise there are a variety of twisting ansi spooling operations Sec fig 7. The winding and twisting of the yarn is followed by number of more or less related operations The thread may be converted into cloth tape wiek brake lining tubes braids or formined into rope See ligs and A small amount of the product of the witulers and twisters is treated by passing through a sizing compinail atul subsequently dried on reels before being wound again , tubes for the turket 11 WEAVING The weaving of asbestos is done on looms that operate in the con ventional manner Both cloth looms and tape looms are used See figs 10 and 11. On the latter brake lining asbestos tape and wick for oil stoves are woven The tape looms differ from the cloth looms in that the warp is segregated into several strips of material and in that there is shuttle each strip of warp The weaving of all strips proceeds simultaneously one mechignism operates all shuttles and a single reed suffices all warps Looms for tape weaving are made in multiples of 6 spaces lip to ns many as 30. Both dry and wet weaving are employed for the production of both cloth and tape In wet weaving the warp is passed through a Shallow pan of water and the cop for use the shuttle is dipped into water Baagne Dry weaving of broadcloth produces much lint and dust The threads of the warp are continually rubbed past encis other as they are moved frony positiona above or below the line of the shuttle which is shot from one side of the loom FIGURE Exhausted BRAIDEN to the other at each chunge in position position of the warp Fiber fragments are rubbeil from the threads at each change in their position and the fanning of the air by the moving machinery curries them into the atmosphere in and about the doom The rate machinet are used fu both wet and weaving the manufacture of asbestos woven products at some of the plants studied the warp is formed on individual looms by harnessing the thread from many spools which are hung on ensel nicks harnesing others  Y a 12 the warp is first wound on a beam from the individual spools and then transferred to the looms The latter practice makes a more compact unit as creel racks occupy several times as much floor space weaving as the loom The creel racks are attended by a worker who is kept FIGURE IGADCLOTH WEAVING LOOM busy tying broken threads and replacing empty spools with full ones The occupation involves an exposure to asbestos dust for which the looms are largely responsible The asbestos cloth is usually shipped to firms that convert it into gaskets fireproof clothing and other products that require a home e . 13 products combustible fabric Some asbestos wick is packed for the market without further treatment Asbestos tape is usually sold to other industries Some plants that weave brake bands sell it as a crude woven ribbon of fabric to finishing factories while other manufac turers of the material convert it into finished WIDE SECTIONS SECTIONS SIN THE OF thING Showing HANDS Lom WOVEN Weaving -BRAKE 11 Figung BRAKE MANUFACTURE The manufacture of brike hands first being the impregnation of proceeds in several steps the the woven fabric with either an ass phaltic compound or vegetable resin The latter is the of treatment and is newer farm rapidly supplanting the former Following this operation heat treatment is applied in specially constructed oven Ja practice the ribbon of woven asbestos passes first into a vat of the 14 treating substances and thence immediately into a baking oven These operations are carried on in a building that is well ventilated and which is removed from other structures sufficiently to reduce the fire hazard The treated asbestos fabric is now calendered into uniform width and thickness and one surface is ground smooth The brake material is next cut into suitable lengths and holes drilled into them according to pattern Finally the finished brake bands are branded and packed for the market In some plants molded brake hands are made of asbestos yarn and British British Preetige Capital letters exployed to denote processes that are not in use in the American pleats involved in this study FLOW SHEET Cade estos Crusher $ ci 4 KATHETIC SEAMTER . SHAKER SOREEKS ROTARY THRII SEPARTED GITEX; Rew cotton cleazed in opener and picker - converted into a of fell known as rell laps FRED I Willower PRITISH EXPIST VERITIAL VERITIAL VERITIAL VILLOVER EROW AS A CREIGHTO ORDER Americas practice - | cotton added at TEMINOLOGI this point followed Screening SITYING MITISM ) won eee.! by Piezar mixing Svece Bias Roving Laminder af fl about stailar to thel for America practice FIGURE FLOW SMEET OF BRITISH PRACTICE synthetic resin The process consists of passing asbestus thread through a bath of resinous material and immediately immediately winding it morg spoid eylinder eylinder Enough of the risin will adhere to the asbestos Inked to form a uintrix into which the asbestos thimad will be indieshdek When the desired thickness is obtained the spool or eylinder eylinder is given heat treatment which hardens the resin The exlusien of material is removed from the spool niil into tuner^w sertjetis ... circular bands this formed are ground machined and uthurwise uthurwise make ready for the market . ~ nl 15 The grinding or surfacing of the brake hands produces considerabie dust In the plants studied exhaust ventilation was used to contrel the exposure BRITISH MANUFACTURING METHODS British practice differs in many respects from American practice The same type of machinery is used in both countries but in British factories control equipment seems to be more generally used than in American factories British factories specialize in the proilur tion of fine yarn and this involves numerous differences in practice In England the processing of the asbestos begins as it does in the United States with the crushing of the ore but when this operation has been completed the manufacturing process does not parallel American practice until the fiber has been carded and is ready for spinning into yarn See fig 12. , After crushing various grades of asbestos are blended in a machine quite similar to the conventional type of rotary concrete mixer It of passing interest to note that the same device is used for blending tea The blend of asbestos is passed through a magnetic separator where certain mineral impurities are removed It is cleaned furthe on on rotary shaker screens where some grit and fiber fraginents are eliminated After screening the material is fed into a willower The British employ a vertical willower that is known as a Creighton opener Its action is similar to that of the American willower and the internal revolving mechanism is retained The willowed material is subjected to a final cleaning on a second set of screens such an operation is termed sieving Willowing is the lust of the cleaning processes after which the asbestos is placed into bins and is thereafter known as stock It is now fully prepared for carding The practice at the plants included in this investigation is to add cotton to the asbestos und then subject the combination to a thorough mixing in a picker machine In England cotton is added to the asbestos the runding machine both fibers being feil sepinitely into the breuker cand The cotton in all probability is prepared for the carding operation on conventional type of combination cotton textile picker machine which opens the filers cleans them and forms the material into laps The latter term is applied to the cotton which is formed into a broad ribbon of felt and then wound into u roll English carding machines are lattice equipped with a feeding conveyor conveyor or upon which first the asbestos mud then the cotton are placed The asbestos is added from a weighing box that is supported over and near the outside end of the conveyor This box foils neliestos m accordance with a predetermined ratio of the fiber to the cotton When a certain cotton weight of asbestos dias necumulated in the box an mechanism opens the bottom allows the material to full upon the 16 lattice Further along a roll of cotton felt rests upon the lattice and unwinds as the conveyor moves forward Thus asbestos covered with a layer of cotton felt is fed into the first machine of the carding unit The carding operation has already been described The roving produced by the carding machines may be converted into yarn on either one of the two machines both of which have been discussed As was pointed out the ring spinning machine produces a much finer yarn than the mule spinning device Since the Britishi specialize in fine yarn the ring spinning frames are used virtually to the exclusion of the mule spinner The preparation of yarn for the market and its conversion into woven products will not be discussed since they are similar to the processes used in this country OCCUPATIONAL Analysis anD A DESCRIPTION OF THE CHIEF OCCUPATIONS The occupational analysis of the four asbestos plants covered in the present investigation is shown in table 1 Table 1. decupational analysis of workers in the asbestos textile manufacturing Industry 1 Section and activity Plant | i MFKFMFMFM5 MFK5 | | Preparatio Forem cece e enn e ne co eeneesseneees Crusher Willowers.... iceceeeee) | cses eens |B fewneeee rere Number of warts 10 Plan B i Plant C ! That D MFKMF M5 MFKFMFMFM5 MFKFMFMFM5 MFKM5 MFKFMFMFM5 MFK5 MFKFMFMFM5 MFKFMFMFM5 | B svsecesolsccoeee i @),.r.r.t.s.ecepressvesals. =pri Mio... \ | ove vets Tora MFKFMFMFM5 MFKFMFMFM5 : 8 . > BL is pt [ccccmcfecescccferccacaloavecsbonsenre | IIIS RII eres Serer we [EIDE seece of p one Un UT : fi : Splanine Mukinn Mukinn 7 King seruots seruots Total wee. eee Spooling Spunkers oo... Tailing Biermen Soderatich Tracks Tracks Tanen beeen Ueuate.....00... . : Total .... ' ceca | Qe re i t 1 4 ta | bce et . wee o | cee eee tee oe aoe : sees Sd 1 * WW is pares tteee : 4 er Wee ante? Wwe. 2 2 eee Geese ee ^'d 4 oa... see ? a . is 4 ! . . . - - eee SS 1 oR fC a : . ' : 1 . ea) Bay ' 17 Table Occupational analysis of workers in the asbestos textile manufacturing manufacturing Continued Sean and selivity : Num of wb ate ts f r 8) Plant | Plant + Plant | Plact Tors Wiosior fore ee! Wingen ws Total Treating Trescers Cluth wes Forec Forec ee Second hands Weavers 00, ee Cr le INFI Con inuen a Tipe and brake weste IUC Foreme sevseeees entert : and Never chase Caleb jerers jerers Ce cee rs o, 117 re Taal el, Ae, Cord ropa and braid worE teens | Fiownsor Trester and driers Cabod oer een Orig . ..... + Curlers drillers Curlers and drillers fie ... teccccdeccewelovecue, . es ceneabrencces o. -- . t sees Tle 1 | 3 I.sessesel ceeweetseceenes te seesei Reeerees bpm seewess] a]... 1 sreceee 0] esesen Tocal fe. veclecceecel, General Ishr L LibierbLeibrer osu, Up ol. Watchmen 77" Shugung sleek Le eres Phe asenaes a eral | 6}. 3}. ! Inlal beeeesecas Critice : tests Superinten .. Hiner tase ws { a errs Bo, 4 Guu ' a: Toll ... t~-r uns total . Is rT) a= a eee the ~ ma) Tho, (ei og * . | ceseeeel a 3 ? eeeveades ts Pneen aa o. tafersccsaproscnae t sensvenl ay... 2 " 1 es wy eo, eee |t veesel a er a 4 eo, 11 = = ' oT, 2 ! ar oo ~~ 4 s eS tae = = . Further adoptest in Reference to tuble 1 shows that a number of as foremen and second hands These men have been listed from the terms have been adoptest tinie cotton textile industry They do not always mean full and sseucpoenrdvifsuonrdysduties as might be presumed in most cases foretel to which are engaged in all the netivities of the department they are ussigneil not madein the brief mention of these a~ rijations occupational descriptions descriptions which follow follow ISIS PREPARATION Crushermen empty the raw asbestos contained in pound bags into the pan the crusher They also operate the crusher and remove the asbestos fiber after crushing Willowers or openers handle crushed fiber and waste roving fed into the willowing machine by means of pitchforks The is usually blown into a special bin The waste accumulated removed several times daily by the willower Willowers also The crushed ore is willowed materia by the machite is operate sereens for separating coarse granular material cobs from the fiber Pickermen make up the asbestos Latches pilingi according to speci^-estions and pitch the material into the feeder hopper and the picker machtre The pickermen in some plants may hand truck to special hiiis the inateria nhi^"nis blown from the machines CARDING Corders operate the carding machines and cleat them when necessary Stockmura handie the stock prepared by the pickermen The material is eni - veyed by hand trucks from the stock bins to the card feeders Tenders look after the stock feeders and roving jack sponis removed when full and replaced with empty jack spoo tender and carder are in soine plants interchangeabie The ; The latter are occupations of SPINNING Mule spinners operate the mule spinning frames Ring spinners operate ring spinning machines Helpers bobbin boys assist the mule spinners and ring spinners conveying full jack spools of roving to the spinners and carrying empty spools back to the cards They also transport the spun yarn and attend to the roving jacks and bobbins whenever required SPOOLING TWISTING WINDING AND TREATING e Spoolers tend the spooling machines and handle spools on which the spun yarn la wound Twisters and helpers operate machines that twist spun material into heavier and stronger yar~-~- Winders operate yarn winding machines predominantly Treaters pasa yam through special cotipounds usually starel and wind it on large reels f^...rdrying In brake lining manufacture treaters haulie asphalt and resinous materials with which the prisiuet is impregnated Yarn pickers wrap and box finished yarn CLOTH AND TAPE WEAVING Bridelith incavers operate both dry and wet wensing loomis Tupe irearers operate beans for weaving tape and brake luiing aisate trac. Inspectors asul cuicaderera cuicaderera suspert and examine all woven material for de festa and pass tape and lirske bands through eslendering machines tu achieve sic street wiith and tik~ kitewstik~ kitews Creviers attend to the email racks Cap winders operate windwindingwiinndig ng for use in the Inom shuttles on which machines machines the warp thread speeds am tiaminteel tiaminteel which would thread so metal sprichies carer helpers helpers ti They gisa inualls furtadle attend to the drying of bermudi koth which mate risk fist the cribers cribers and weavers bas Het war 19 ALL OTHER Cord rope and wick workers operate special cord and niaking machines and braiding machines dining finishers include trasters and dryer men calenderers who operate calendering machines for squaring uneven edges grinders who smooth off uneven surfaces and cutters and drillers who cut the finished band to required sizes and and trill it for riveting to brake shoes for automobiles and other machines In the plants studied these occupations were interchangeable fieneral labor includes those occupations associated with maintenance of envip- neas ment and generation of steam They also include janitors natenmieni and slupping clerks Superintendence is concerned with the supervision of all plant setivities RESULTS OF THE ENGINEERING STUDY DEST STUDIES In the present study dust counts were made by the impinger method 2 using ethyl alcohol and distilled water mixtures containing Trom 25 to percent alcohol as a collecting fluid Two sampling methods were used for collecting dust for chemical analysis " Settled dust samples were collected at the breathing level and 2 ats suspended dust was collected with a small hand vacuum cleaner fitted with a removable paper type filter The latter method is similar to a procedure developed by Hatch 5 See fig 1 In addition to chemical analyses petrographic analyses were made on several samples In order to determine the particle size of asbestos dust an Owens jet apparatus was employed 2 The samples cuis lected were measured by means of a filar micrometer at a magnification of approximately 1,000 diameters oil immersion Photomicrograpi.s were also made of dust obtained by the vacuum device de- scribed above NATURE OF THE BUST FOUND IN ASBESTOS TEXTILE FACTORIES Composition Table 2 shows the results of chemicul amulysis of settled dust samples obtained by the Hatch method 3 Examination of these tables does not reveal significant differences among the various samples will be noted with one or two exceptions that the tota ash no water of crystallization present does not vary greatly The value of 54.5 obtained for wet weaving sample S is due to the moisture content of the dust sample Calculations of composition composition on an ash basis bring the values into closer ugreement that indicated in etfives table The results given for sample in table 2 are for brake liang which has been impregnated with resinous compounds et . SUI in kan plantes Seer, 0019 Meu astumine matriek flat astumine sunt in these Cartura has the follising follising Pullitant nt, Maoh uta bowie: SVy@tevay Naber Vel Ne Tsp bee 1.1 * 20 TABLE Chemical analyses of settled dust samples obtained in asbestos teziste plants Department in which WB Dies were COLLECTED vurage chemical evenmities evenmities of samples samples perceptage: ! AID 510 . 0 C Med i FeO, Remors , Preparation 1. ifledt A 2. Preparation piant B .. 3 Cards PILOU ^ 4. Carmine B 5 Cwa 101 B 6. Muie spising pant : WRVICE pleat A Weasing ipisni A V. Weavine piant R 36 Weavine hian B 11. Brake pisal grindiot 12. Duit fmm excione enn Mosted 10 expaust Statero plast B 447085 447085 447085 874 447085 61 253288 253288 253288 253288 2 1.3 KASAPA KASAPA Nt KASAPA 363 KASAPA KASAPA A8a2 A8a2 A8a2 A8a2 * : : : 10 171 O62: 2 285 HI 13.5 24 31 le BW v3 ee ay let, | 108 .e , Le: sf} 34 $4 213 110 8 , in J iv 1.9 BS 42 i 6a. 14 10 ae 66 112 o 49 , 5,3 7 26 Near Willow To atemne barv^ Lin B61 of cardi Tije #Pati loom 11. EV21108 AWEI AWEI CYBERT Nom C t 204 metal fi th bromeform barve 13.2 13.2 = 31.2 31.2 31.2 10 Monty card room dus : Combiz JoI1OM JoI1OM TABLE Chemical analyses of suspeniled dust samples collenteri " an ashesine . teztile plani Department in which Wa Oipoes ETE COLFCLE 1 Average chemical composition of Mampies Mampies LAYLAGE LAYLAGE , { A | 210 2,0 C MgO ForQr ReRmeamarrkkss : 13 PreparatiKONTO -} 14. Cardide + 35 Mun ini 16 Ring spiBBIDE 15. Dev weaving In Wet WebLiBEA WebLiBEA 16 TELLO 2 Spable ) 21. lading 22ST : 60226 60226 85 60226 716 is 2) oi] ' AKA,, AKA,, AKA,, AKA,, AKA,, = # AR AR ~ 08 i ~ 5 ~ 4 ~ .. ~ af att 10 120 ae] | A260. Lu, wo. a | 35 BOMB. .@ Hw) ee oe AE | 21; 34) 6] 6) AO AG 1 SH n a: BD 06. hO) Psr75 122 5atipit ba Bet 2 muie spion Ne Ting wing nuch.B Br semis SPY105 woe New FemNE MARiors MARiors NUGE NUGE S TIBU.Sachines TIBU.Sachines 1 Communal sides ) Oprrenver camu (pu par m i reee m. The losses on ignition of all samples analyzed are due to the presence of cotton fiber and moisture The 30.5 percent loss on ignition of sample 21 in t^/lle3 is probably due to the presence of cotton fibers In passing it may be pointed out that no enrbonate of the order reported by Hurlibut and Williams was found in any of the samples nnulyzed 6 No quartz was found in any of the samples examined petrograpius cally The consistency of the results indiented in tables 2 and 3 is more remarkable when the physical characteristics of the dusts are taken into consideration Figure 13 illustrates the gross appearancoef the dust samples taken with the vacuum cleaner device above mentistesi Each sample shown the figure represents two grums of dust Thar are conspicuous differences among the samples both in color and bulk Preparation and carding produce granular material Wenying _s ace ea at oe ig Py WINDING 21 Figure ) COLLECTED COLLECTED WITH VACUUM CLEANER DEVICE GROSS APPEARANCE APPEARANCE OF SUSPENDED DUST SEE FIGURE } oe eee 22 ~ samples on the other hand are bulky the difference probably being due to the presence of long asbestos and cotton fibers in these samples Carding and preparation samples contain cobs which are present in the raw asbestos The darker appearance of the samples shown in the top row of figure 13 is difficult to explain It is probably due to vee Cad erm a4 the xwt 4 Sigs NPs % be & ue SPOOLING ae 3 aes SPOOLING a TWISTING DRY WEAVING WET WEAVING FIGURE 14 MICROSCOPIACPPEARANCE OF Suspended DUST COLLECTED A * VACUUM CLEANER DEVICE 200x contact of the spun asbestos mixture with oily metal surface The microscopic appearance of the vacuum cleaner asbestos samples ilustrated in figure 14. presence of both cotton and The ane fibers and of small particulate matter is readily noted The dust from the carding room is most striking It has few fibers and it considerable particulate matter 23 photomicrographs Particle size The measurement of dust particles suspended in the air of asbestos textile plants is difficult because of the both asbestos and cotton fibers presence of The differentiation of these fibers under the microscope is not always possible especially when the fibers are short and fine Several samples obtained with the Owens jet apparatus were examined with a petrographic microscope in onier to estimate the proportion of asbestos and cotton fibers but no satis- factory technique could be developed for this purpose article size determinations based on Owens In this study three methods jet samples were inade by 1 enscope projection device 2 a filar micrometer attachment to a microscope using oil immersion 1,0001 and 131 by means of photomicrographs Data obtained with the euscope showing the percentage of fibers irrespective of whether they are cotton or asbestos are presented in table 4. These are based on Owens samples and not on impinger samples With regard to the selectivity of the device used littic information can be given although it is known that for discrete particles the selectivity of the Owens apparatus and the are the same 2 impinger TABLE 4 -Relution of Abers to particles in various Ovens jet >. ale : Activity WeavingWS eaI viD ngE Piening ' Carding . 5. Tuning TRISLIOR TRISLIOR ' Pushing '.. ee. Plant D. Phol of of Number i Fitnes Number Tanks | counted RUUBIN + | Toli MARSl 8 ot ? , 2388 AAAAGXS | ' 2388 NY : AAAAGXS == AAAAGXS AAAAGXS 315 ~ .. yes 239 . 12 : == AAAAGXS ~e 4 AAAAGXS Pay 1 Dust The results given in table 4 indicate that the highest percentage of fibers wenvers are exposed to This is to be expected because the warp threads fry as the shuttle crosses them Samples collected near the pickers and carers have fewer fibers while the dusts which crushermen ure exposed have the least proportion of fibers to The relatively low percentage of fibers in suspended dust the small number of fibers observed while making dust coeuxnptlsainofs impinger samples The latter were usually usually dilated to give 20 in Su particles per quarter field Hence except except for weaver's which considerable fibers samples in in were observed fibers are only rarely found making emits of other samples td fibrous and montibrous counts include bath particles irrespective of size Table J Mustrates the size range of particulate matter Tw bundred particles in each sample sample have been measured by means of the 1.1 -- Sa: 2 tment nN 24 filar micrometer As may be seen the median size varies from 122 122 microns to twice this value Fulton and his coworkers used an electrostatic precipitator to collect dust samples and calculated an average value for the total distribution of fibrous and nonfibrous of 1.33 microns 4 The median size for particles less than 5 microns as deduced from data given by these investigators is approximately 0.47 microns which is much lower than the values given in table 5 of this report This difference can probably be attributed largely to the type of sampling devices used in the two investigations Table Sise frequency distribution distribution of particulate dust suspended in the air ni benlos testile plants bajo bajWo AS LUKT" 10 ERICTOO Preperation 2000 ooo... es Curains te pee Mu Hun oe v4 pao -1.0 .. ...... seas Vee Wegrine cbreemielath , yr Weaving shap cee eeezkaan Tree: Percentage troqueary of math farticle Bite Brown 18 MED standard deve 1100 0 05 1 12 25 3 3 AAE AAE 0 05 10 12 8 25 3 10 AAE SUN or a 4 90 9 421 421 2 299 3 wets P | | | ] || || 1 | $n 88833 85AZHA wiia n 37 1 " 88833 85AZHA PAPE 16 4 S :) U J 3 31 0 tl 88833 PAPE 8 ... I 1 1 124 S 88833 PAPE 8h OO i q 12 1 88833 85AZHA PAPE : =Y " en Pans 3 88833 88833 2 | eePas > 2 a 1.5 3.0 Me ra. he , In determining the length of fibers present in Owens samples photomicrographis were used It was necessary to use this method of measurement because of the curvature and matting of fibers in the microscopic field This difficulty was overcome by using conipass pointers and measuring each fiber visible across a given section of the photomicrograph The size distribution of fibers classified by occu pation is presented in table G. The fibers mage from as little as 2 microns 450x magnification to as high as 400 microns The median sizes as may be seen by reference to the table range from 7 to 16.3 Fulton's data indicates assuming all particles greater than 5 microns to be libers a median size of 15 microns Table 6 Median t H | length of fibers Activity Activity sampled with an Owenjset apparatus j Melun 1 warttiot | { Arwrs se 4 Sunfull .. fe Picking . > L'ahlini band THINK THINK a 126 Werving Werving tbrukshikorite tbrukshikorite 1+ No size frequency distribution with regard present the mir has been tunde in this study noted with few exceptions that the width of to the width of fibers However has been fibers collected by the 25 Owens jet apparatus was less than 0.5 micron This is in agreement with the results given by Fulton who shows more than 75 percent of the fibers measured by his projection method to be less than this size DULT CONCENTRATION IX DIFFERENT OCCUPATIONS In earlier studies of the dusty trades carried on by the Public Health Service determinations of the average dust concentration have been of great value 1 in describing the working environment 2 in making comparisons of the effectiveness of different methods of dust control and 3 in relating health conditions to dust exposure In this study 242 impinger samples were taken and counted and the results have been classified by occupation in tables 5 to 15. Each of the occupations carried on in asbestos textile factories has been dis- cussed separately in the following section and data for the entire industry have been brought together in table 19. In this industry there are relatively few occupations in which workers do two or more kinds of wor which expose them to totally different dust concentra- tions In such cases the several exposures have been weighted ac- cording to the average time of exposure For example in plant A willowers are engaged in the following activities willowing 5 hours picking 1hours storage work 1. hours These activities are associated with exposures of 2.3 30.3 und 16.4 millions of particles per cubic foot respectively Hence we may tabulate exposures as follows and calculate a weighted average Table 7 Dual exposure of willower plant A | of on. Time | { Stilling | Aruvity f t bar Ast Ast particle - I bar ber PRY frum H @ap) MPPC sutvet ; ( i {| r) axe: Wilesine.. f : : | a 220 11 as ee may bt, wa 21 ' essseaveceeee, 13 *** llon tantin D rers Fok t^ kurt +11.3 m^linepartus per mtakut buit The average dust count of the 10 samples in the above table enlene lated without regard to the duration of exposure would be 187 187 million particles per cubic foot Preparation Preparation Preparation includes the occupations of crushermen willowers and pickermen In plant B. these three occupations were conducted in the same room while in plant & only crushers and wals lowers worked together Picking including piling the dafter plant was done in a separate room The dust exposures are madin ented in table S. 26 Tabur Dust exposure of workers in the preparation department ' Occupolina Number of abmries wxeo Dust ones tration MPPCF * Crushermen Willus 2. ee Prebrimen -......ceeeee $ roid Se 73-3 11 1-16.11 243-24 ( Weighted 6uerant 6uerant e It will be noted in table S that the crushermen's exposure is relatively low In the plants studied this work was carried on near an open door However it is doubtful that this occupation generates the quantity of dust shown in the above table It is more than likely that willowing and picking and even carding contribute to the dust ex- posure of crushermen Willowing of crushed asbestos is not in itself productive of much dus 11.1 million particles per cubic foot Only when waste roving and fly fromcyclone collectors are will wed ines the dust increase Dust counts as high as 99 million particles per cubic foot have been obtained with fly A continuous source of dust production results from the manner in which willowing machines are fed The material to be willowed is raised waist high by pitchfork causing considerable spilling Willowers also operate shaker screens A pickerman performs several kinds of work This is especially true in plant B where pickermen not only assist in piling mixing of cotton and asbestos but also aid in stacking the material blown from the picker machine into storage bins This mentioned activity produces dust concentrations ranging as high as 241 million purticles per cubic foot Pickermen usually work in pairs and alternate in feeding the picker machine and tending to the storage bins Piling is done by both workers together and contributes to dust count- count- averaging 16.2 million particles a Picker machines like willowers are fed by pitchfork a metheni which produces undesirable dust This is true even where picker mas chines have hunded feeder boxes The picker machines studied were equipped with oil sprays pres sumably to bold down dust The ineffectiveness of this method at dust control is shown by the dust counts which exceed 50 million pare ticles per cubie funt of air Carding brushing and combing of asbestos and cotious liber mixtures by carding machines creates considerable dust The carding action is such that small colis and line tule millierent to the usbestos liber are thrown into the air This effect is nerentuated ta the fan action of the brushes The granular and nonfibrous appear- appear- ance of the dust present the air of carding room- has been shower shower na figure 10 me 27 The exposure of workers in carding rooms is given in table 9 Table Duet exposure of workers in carding department Occatio Sumter of + ,, -- Dust ron CePA IMPPUF IMPPUF 21 21 Carriers sort tenders .. - Ok +... cccecee eee ee vu ! | Weighted Weighted sYPTIER The average dust concentrations in both plants A and B were similar Counts as low as 6.4 million particles per cubic foot were obtained for some carding operations where machines were operaterj at relatively low speed and as high as 139 million particles for high- speed operations In the two plants studied which curded asbestos mixtures all equipment was hooded and exhausted Under the methods of operation which required necessibility to the machines compiete enclosure was impossible Consequently exposed brushes revolving at high speeds often nullified the effect of the control system Nur could air flows in the exhaust system be increused since a considerabcolnsideerable amount of valuable fiber would be drawn from the brushes and this would reduce the weight of roving to an undesirable extent Spinning. Both mule spinners and ring spinners are exposed to similar dust concentrations The range shown in the following table table 10 for each occupation is probably due to the presence of more spinning and weaving equipment where the dust concentration is higher . Table Dual exposure of workers in mules and apinning di peritas peritas uta t Groo gniinn of Xumbt | Trast em - |n , tates MPPORT Mu opener... + King sunnINE 0. 62... ee! 8 , sg wet Vese spinning operations require considerable space and are gener ally separated from other activities On other hand ring spior ^' is done in close proximity to spooling and twisting and it is possible that the dust counts are influenced by these operations The results obtained for nude spinning check with those given by Fulton and lus coworkers 4 Spending twisting and winding The equipment for these operas tions is generally grouped together and therefore is dithic a^ obtain a clear estimate of the amount of dust produced by each 28 The average range of dust concentrations in plants A and are shown in the accompanying table table 11 Tablo 11 Dust exposure of workers in spooling twisting and winding departments Ortupelion Number 187773 16500 Dust red tenitation MPPOF . Occupation : Namber empi empi lates Trust me CRALT Le MPPOR MPPOR priniem . Tuners and helpers Biversal Ridders A 2-13 Rovise winders 20 2-13 Yara pers $s J. are treatETS A 2 te 3 1 Of the occupations listed in the table twisting appeared to contribute most of the dust in plant B and to influence the exposure of spoolers and ring spinners close by Twisting frequently produced concentrations of over 20 million particles per cubic foot of air yet counts below 10 million particles were not uncommon Twisting involves a considerable amount of fraying and when grade materials are used the dust production is increased Winders and yarn packers are exposed to lower dust concentra- tions than spoolers and twisters Here again however because of the proximity of the latter producing occupations the amount of dust actually generated cannot be estimated It is hard to conceive of such operations as roving winding and yarn packing producing much dust Broadcloth wearing dust created during the weaving of broadcloth depends upon the number of warp threads per unit of | width the quality and width of the material woven and on whether the operations are conducted dry or wet If the warp threads are close the fraying action which takes place during weaving produces a considerable amount of dust With some looms the dust conceni- tration was found to exceed 140 million particles per cubic foot Average dust counts obtained during weaving operations are shown in table 12 TABLE 12 flust exposure of workers associated with binailcluth irenring Chervimi mill + Numitope od lust rene SL Le el laben Were emt neiper. ery ld. Wer. * Cpweter. ami hesiees weaee : Tressention cab cabo overyv cabe over ry y MO so Eo. ne | = t Sg Paes? feu eo lwo a Come Vtw @ " ... Weaving Weaving operations are intermittent owing of warp thrends Consequently workers are to frequent exposed to breakage alternate alternate 29 periods of high and low dust concentration On the other hand weavers must pay close attention to work and are subjected to heavy exposures while the looms are in operation The dust counts shown in table 12 for weavers and helpers illustrate the differences between dry and wet weaving Both dry and wet weaving are carried out on similar looms in close proximity However operators are interchangeable and are not specifically designated as dry or wet weavers Under such conditions it is in 'possible to gauge the actual exposure of a wenver The low count of 4.7 million particles per cubic foot given in table 12 for both dry and wet weaving is for a small plant with one dry and one wet loom in operation side by side The higher counts are for a larger plant manufacturing all types of broadcloth and at the time of the survey having from 8 to 12 looms in operation In view of the high counts obtained during broadcloth weaving it would be expected that creelers are exposed to comparable concentrations That this is not the case however is indicated in table 12 With all looms in operation us is frequently the case the counts might conceivably be higher The same is also true of inspectors calenderers and cop winders who work in the weaving department These occupations do not produce large amounts of dust Tape wick and brake wearing The dust exposures for tape wick and brake weavers are indicated in table 13 TABLE Dust exposure of workers associated with tape trick and brake toranj : Occupatio 1 Nunber of | Just Cas | SPPCF BANH | SRIN letre Wape Wape quiltet quiltet "3 cavers (oraze ..... [ Cpeeeer wes..... ... Commins. coc... eesess t sean ft | aeRO tem) ] a^' | It may be seen from this table that tape wick and lining wenvers ute exposed to lower dust concentrations than brouelath weavers Excepting certain types of brake hands the fraying of the warp threads during weaving is not as great as in broadcloth weaving However with heavy brake bands such as are used on trucks and hoisting machinery the dust concentrations become high and com parable to those obtained in broadcloth weaving in the manu facture of such brake bands that creelers are exposed to counts of 20.3 millions of particles per cubic foot of air Calenderers being at some distance from the looms have low expumure The dust counts obtained for the type weaving weaving here discussed were consistent in all four plants studied 30 working Curl rope and braid Other activities found in the asbestos textiles plants are concerned with the manufacture of special products such as cord rope and braid and in treating and finishing yam These operations produce little dust as may be seen by reference to table 14 Table 14. Dual exposure of workers manufacturing and finishing specini products ** TULBION TULBION Ls Number of 1 16.03.18 + taked Bust ens. PERITATIO MPPUY funt fute and braid widart steps . 11-10 we 17-1917-19 17-19 The equipment used in manufacturing these products does not operate continuously None of the operations of cond making rope making or braiding requires time personnel and a small group of workers perform all these jobs The highest dust count 10.2 in t ? 14 is for braiding The counts obtained for yarn treaters ate int aenced by the operations undertaken nearby Brake finishing This generates little dust In the plants studied finishing operations were conducted in separate rooms or buildings Dust counts are shown in table 13 Table Dust exposure of workers manufacturing finished brake lining Occupation Treaters and lrare Treaters and Sieametere 20! ' Number Dust | i m EPAiration | ! Laten IMPROF h Deculminin * Number lust Ame ed ners +18 | takeo FAMPPUE | i] ]] ci fipre { i it | fl vl 1. he O27 Corteve amet . 00... .. ll. wees Combes. UII 1 ts ms 1s Workers employed in the occupations listed in this table are exposed to dust which differs in composition from the dust found elsewhere elsewhere in asbestos textile plants This is because the dust generated by grinders cutters and drillers of treated stock is made up of resin asphaltum asbestos and metal 11 table 2. See analytical results for sample In with Miscellaneous occupation addition to the groups directly concerned the manufacture of textiles a considerable number of workers engineers general laborers clerks und superintendents are engaged in other activities With the exception of certain foremen these workers are exposed to low dust concentrations The data presented in table 16 require no comment 31 Table Dust exposure of murerilanenus groups Occupation j SOME! { Dars \ Dust ron- Biration Occupation I teten | ---- -- ---- - ; Number samples % " rere takra MPP F Fanneers Fanneers . 2... .escecncrwes nem nem . ses eacnencos |2211 2211 BEARER office a 1.2 ee F A Sufwriate eee 2 i) ,, , ewr Watenmon 2211 3 Sufwriate office NV . shipping cik] : 2211 .12 C a eeccncaceccces NV aa te . a. Samples and esposures depend on the activities with which they are associated PREVIOUS DUST EXPOSLEE The dust concentrations discussed in the preceding paragraphs represent present conditions The officials of asbestos textile plants have in recent years attempted to control the dust hazard In the plants studied efforts have been made to exhaust picking carding and brake grinding machines Another plant which will be discussed later lias extended the use of control equipment to nearly every dusty operation concerned with the manufacture of asbestos textile A knowledge of the exposure of workers prior to the introdur - n of control equipment is important in correlating clinical findings with dust exposure In order to estimate past exposure the air flow through various hoods attached to carding machines in plant A was shut off for 2 hours Dust was allowed to accumulate for 1 hour prior to sampling The dust thus generated caused much inconvenience to employees in the course of their work For this reason permission to shut off exhaust equipment was not granted in other plants studied Carding machines are sensitive to slight air movements and are consequently difficult to regulate Once they have been adjusted any external disturbance affects the weight of the roving produced The dust counts obtained under conditions simulating those prior to the installation of the exhaust system are shown in table 17. For contrast present exposures are included TABLE 17. Dust enunta when enmiral meQSURES ARE HBed and when they are not ... ... ... on ... ... ......... 1 120 ... ... - ...... URbySSe 111-114 111-114 ... ... AMPPUE Cee teen ee A Dr. Re ) slost aver. * - 11.01 ... 10 AMEE b. MEE MEE : cccees mustermen . : Within 2 4 [i a es 48 48 48 eas ee _ee ... - al 2. a 1 T Zl Mu enner Iline sanje | * . qood to + 16 ......... _ ~ . mse oo oan . - - : The low counts obtained for the orempations orempations orempations due to purtition which separates them from listed below the cardingcarding cariders as machatic s machatic 32 Mule spinnerarse located immediately beyond this partition and the dust count shown is due to dust which has passed through an open door Three dust samples obtained in the carding room 1 hour after the exhaust fans were shut off gave counts of 77 73 and 78 million particles per cubic foot At the end of 2 hours a sample taken in the room 61 same ~~ gave a count of million particles . No major changes have been made in plants C and D since the start of operations The dust counts made are essentially the same as those which have always existed On the other hand no data are available for past exposures in plant B. This failure can be attributed to several factors but principally to the gradual expansion of the plant with the growth of the industry which increased the amount of equipment and the changes made in recent years with the ( exhaust system The first of these factors appears to have affected all operations conducted in the plant while the latter is restricted to the carding and preparation departments In addition it may be pointed out that plant expansio has tended to increase dust produe tivity while the introduction .. exhaust systems has reduced it Hence it may be assumed that the exposures of all occupations in plant B following carding were probably higher during the study than prior to expansion It must also be remembered that more men have been working since the introduction of added equipment than at previous times INTERPRETATION OF DUST COUNTS The average dust concentrations just discussed make a satisfactory measure of dust exposure for most purposes In correlating medical findings with dust exposure however it is frequently advantageous to express the dust exposure in units which combine duration of exposure with average dust concentration An easily calculated descriptive value was developed during statistical analysis of the results of an engineering and medical study of anthraco If a worker's dust exposure has been unchanged for all pract5 io1 nl purposes purposes during his period of employment the average dust count in million particles per cubic foot is inultiplied by the duration of exposure in years The product is used as a numerical measure of his totul dust exposure If worker has changed his oceupation mid in so doing has changed his dust such the one exposure appreciably u enteulation shown in table 18 is made 33 Tabl~-18 Example showing the method of computing the dust exposure of asbestos testile workers j . : ' of of * errupmuon ( MPPCF eos 3 KAS 210 34 KKAAS S Fo eeeenceseee \ ae8 * - 12 mn Plact A. Prior to installation of exhaust symeN Weighted dust exposure 3x millings of particle let tuhie lont exposure " 10 Quilling parts par har ko et ijen The worker whose dust exposure has been calculated in table 18 would be dessigned a value of 280 million particle in tabulations in which for the sake of simplicity it was desirable to have a term measure of dust exposure tabie 42. for exaniple When average dust concentration and duration of exposure are to be tabulated separately as in table 43 the Individual described in table 15 would be assigned a dust concentration of 40 million -- micles per cubie fout THE CONTROL OF ASBESTOS D _ The control of dust in industry often entails many practical diffculties These difficulties pertain chiefly to the handicaps imposed by control equipment upon the performance of the work being done and in estimating a priori the air volumes required Both of these difficulties are inherent in the asbestos industry The arrangement necessary for removing dust from carding machines and froin loomis which demand accessibility to all parts is evident Added to this requirement is the limited information available with regard to suitable design of equipment for each producing source and the requisite air volumes The latter item is most important in the design of hoods for earling machines inasmuch as air velocities relatively low in order to prevent the asbestos mimxutsutrebse fkreopmt being subjected to air currents which convey them to the exhaust system At the same time however the velocities chosen must be adequate to maintain the dust below the safe or threshold limit The control data contained in the following paragraphs are based on observations made in two plants included in the present study and on data obtained elsewhere by Assistant Public Health Engineer Richard Page 7 The data presented inchide operations for which control methods have been developed In addition the type of control equipment uses in England is discussed although no values pertaining to air resquirements are available in this instaner TRLPANATION TRLPANATION TRLPANATION DEPARTMENT The dust counts presented earlier in this Hulletin for the prejuration department apply to murontrolled conditions A very high degree 34 of control can however be effected under certain conditions cially as regards willowing opening piling operations and espe- The crushing machines in the plants studied picking were not exhausted or segregated In Engiand on the other hand it is customary to enclose and segregate crushing equipment while it is in operation Willowing Willowing machines are often productive of high dust concentrations 36 MPPCF As has been mentioned this dust is caused both by the manual methodpsreuvsieoudsliyn feeding these machines and by the action of the machines themselves Consequently a reduction of dust concentration may be obtained by using a conveyor feeder which eliminates raising materials to waist Lee FOr wn we Perera caetfi FIGURE 15. EXHAUSTED EXHAUSTED PI^ NGSINS levels with forks and using an exhaust above the feeder box the machine housing The willowed and below material should of course he pneumatically conveyed to a suitable bin which is segregated from the prepiration rooin For In the case of two machines equipped with exhaust it possible to reduce dust was foumil concentrations to 3.6 MPPCF hoods loented above the The exhaust feeders drew 400 CFM while the downward exhaust below the willower housing drew drew downward downward 225 CFM to 600 amounts of air ranging fromm CFM the latter air flow being used on fly willower see fig 4 The air handled by the CFM the inch pneumatic conveyocornveyor was 1,800 diameter ducts used this corresponds corresponds to air velocity of 2,730 feet per minute an 9 pa 35 Piling operations are usually conducted close to picking machines The dust generated by this operation may be effectively controlled by using small exhausted compartments or bins Compartments constructed as shown in figure 15 and handling approximately 1.025 CFM of air reduce the dust concentration from an average of 20 to 5.4 MPPCF English practice in piling consists in using exhaust manifolds close to the nixture being made fig 16 Air volumes are not available for the type of exhaust shown in the figure The method appears to be cumbersome and to interfere with the process being enrried on Picking exhaust control used on picker machines is partly ( FIGURE EXHAUST VENTILATOR USED FOR PILING OPERATIONS BRITISH shown in figure 17. One hood is connected at the feeder end and one the discharge end The center portion of the picker is also exhausted not shown in figure With this type of arrangement the dust cones centration averages 6.7 MPPCF This value is considerably lower than found among uncontrolled equipment which exceeds in many instances 74 MPPCF It was found that hoods above the feeder linnilled 500 CFM the downward exhaust the center measured 1,620 CFM at the dischargdisceharge end the air flow was 450 CFM Pneumatic conveyors attached to the discharge end of some of the pickers handled 2,000 CFM These vy ducts were approximately inches in diameter this providing lea a conveying conveying velocity of 2,350 feet per minute LT 36 It is possible with asbestos piles special conveyor belts operating between tl and the feeder mixer that the dust concentration might be reduced below ti value of 6.4 MPPCF indiente above CARDING Two types of contro equipment are at present use on carding machines The re type consists of a hood which i located directly above the ex posed brushes of the machin FIGURE 17 -SCHEMATIC DRAWING OF Ex- MAUST SYSTEM USED WITH PICKER MACHINE ; type of exhaust systems showed a ranging from 72.3 MPPCF when no with ventilation The air fig 18 while the second typ enclosed is totally PX and hausted at various points hip 3 Studies mode of the firs reduction in dust concentration ventilation was applied to 29 % UI. flow for each hood ASS. averaged - - 70 CFM which corte- sponded to six oir changes per hour in the room in which the cards were located be ee. It may seen that the type of hood and the air flow used reduce the dust concentra- eee tion to approximately one- third the amount created without ventilation e The second type of ex- must system used proved more effective than the first in reducing dustiness The dust concentration determi ined from numerous samples ranged from to 3.9 million particles per cubic fout This high degree of dust removal was occomplished occomplished : arrangement with un arrangement similar vs to that iinnddiiccaatteded in figuresFIGURE figures 18 -VERTICAL EXHAUST APPLIED VENTIL and 201 In the primary APPLIED TO AN UNENCLOSED PRIMARY ING MACHINE a ton Cane card hoods e ami bottom of the discharge upward card The secondary . The duet e exhausts frutu tla or joving card is hirmudech at e 37 near the center of the machine The openings and are locatedl at the bottom of the cards and exhaust the bottom fly which accumulates The air volumes exhausted by each opening are indicated in the figure In addition to careful enclosure of the machine proper in the second type of system used the feed box is carefully covered r FIGURE TOTALLY ENCLOSED EXHAUSTED Primary Carding MachINE The design of an exhaust system for carding machines is rendered exceedingly difficult owing to the ease with which carding material lenves the rolls High air flows may seriously affect the quality of the roving produced Likewise a poorly constructed housing may create i = A ~. eddy currents which may prove bothersbomeothersome Any system system de- velo ilrequires care and expers iment in design ie v4 ar erarereh ert ent ts is Oi: Mme p ebtstabu me rpoppn dn #PUOLING AND TRIATING TRIATING The dust generated by sponde EaVsture EaVsture EaVsture PLOY lane ing operations may ingene iously controlled by a system of comes in which the spools an \ 150 150 150 TRUU 010 U01AL0 FIGURE 20 ELEVATION ANd Plan SPOOLING Exhaust System for inserted and exhausted Such is in figure in system is sluown in figure 21 . Euch ease is constructed constructed se as to offer a minimutu manobrand of interference to the work being done In the ease of four Pastes winders 200 spool^>euch cone is inches in diatueter artoss artoss its widest part and 2 inches at the duct comuctions The cones atte each 31 inches deep Two hundred cones were found to hatelli an 38 aggregate of 9,270 CFM or an average of 46.5 CFM dust concentration averaged 2.9 MPPCF discussed above the dust cone TI Without the cone system 13.1 MPPCF concentration for the same operation was mers Twisting machines are more difficult to exhaust spoolers Figure 22 shows a locally than me It consists of system which has been partly completed exhausting the lower section of the by extending a duct with twisting machine equipment Each openings along the entire length of the system attached to the machine is intended to VE 3 we 7 FIGURE 21. EXMAUSTED SPOOLING FRAME exhaust 1,670 CFM Dust determinations ness of this system could not be to establish the effective- of 10 twisting machines made owing to the fact that only one obtained was equipped with exhaust and the were affected by unexhausted machines the counts operating close by WEAVING removing Any system developed for looms represents the dust generated by broad operations accomplishment of one of the most difficult encountered in the design of exhaust difficult theless this has been done equipment Nevers England The effectively both both this country and and 24 consists American system system shown schematically in ligites in of a downward draft hood fitting close 25 rack of the loom and to the shuttle a movable movable upper exhaust hood which on the surface of the operates to and fro by the woven material The latter howal is actuatesi The hood is nation of the loom lay to which it is connected connected to the attached attached se oes main exhaust exhaust duet by miratis of a flexande ven - 39 air tight joint Both the downward and upward exhaust hoods nre Darrow and possess the advantage of high opening velocities The upward hood connected to the loom lay is segmented Each hood used as indicated in figure 24 handles 1,300 cubic feet of air per minute and reduces the dust concentration to an average of 0.7 MPPCF system is thus extremely effec- tive since on uncon- trolled looms the con- centration averages 49.7 and may exceed 140 MPPCF The English method for exhausting looms differs considerably from American pruetice In the former system all parts are stationary fig 25 The luoins are ex- hausted upward by hoods located in front of the operator and resting a short dis- tance away from the lay The hood con- sists of two parts which may be turned back whenever the loom repairs to are neces- sary No data na re- gards air volumes used ay Figure EXHAUSTED TWISTING FRAME in this type of equipment or its effectiveness in reducing dust arc available INSPECTION In some plants asbestos cloths are brushed during inspection The usual proerdure consists in brushing the cloth from above and below is it pusses over the inspection table An inspection table " this type with exhaust is shown in figure 26. The hoods user are located near the cloth brushes and extends the full width of the cloth examined They are however only half inch in width stily made of an inspection table such as discussed above indicated that two hoods located on either side of the eloti handles approximately 730 CFM each A third brush and hood lowated lowated ma 4162 4162 mi mi . . a - e- . 40 the jack spool at the end of the inspection table handled 192 CFM These hoods reduced the dust generated froin a value of 11.1 when no ventilation was applied to a value of 0.5 MPPCF with ventilation SUMMARY OF THE STUDY OF THE WORKING ENVIRONMENT The engineering data contained in this report are based chiefly on a study of four asbestos plants Data on dust control methods have been secured in the course course of a fifth plant Two of the four separate study undertaken in a plants investigated were engaged in the manufacture of asbestos textiles directly from raw crysatile Canadian nsbestos received in 100 plants began began openitions openitions with pound hugs hugs The remaining two with gam received from other sources and were concerned only with the ur brake bunding und manufacture of asbestos Tague brand with their treatment 41 Dust concentrations were determineddetermined by means of the impinger technique using light field counting In all 242 impinger samples were taken so as to evaluate the environment environment of each occupation = , oN on Tey . &, Lom =: ~ YN me eC Remans - ee aa 7 - ~ne S [r E l we rini Vous we . Del " . - ee . oe om 4 ~~ 2a _ FIGURE 24 DETAIOLF ExmaustED Shown in FIGUR2E3 LOOM FIGURE 25 Detail EXHAUST USED O BRITISH Type Loow The number of workers employed the number of dust samples taken and the dust concentrations determined for each occupation are presented in table 18. The concentrations range from values values of 0.86 high for shippers to as as 743 MPPCF for samples exerrding 100 MPPCF were found carding and wenvang wenvang wenvang piekermen Dergistea Dergistesta for the ovenpations ovenpations of 42 four TABLE Occupational dust exposure of workers in asbestos textile plants AcsAcsiivivty ity and and occupoccuapatiotB ioB CUBITME CUBITME Willowers . Picker Picker *, Cartine Camion and tenders Stinkite Stinkite ^ DAINE ll. speeners Mur spinners and heifers king speeners and hopers Twisters A mes ree minders Rasan~-z w Milf Milf 1 u2 Virose 11.1.75 11.1.75 11. ... cage ane Wee ee ey oe oi, Comme Comme an bruid workers workers B 1 fro fro T and driers and fing Cutters Amanders Costers General lahor Engineers oe wos Watch Peo Watch PD cvasssesesasenattevenseseccesece, eter... teemesewecesancens PD carts. tee ceeeeeceoee Sufenstreients erdmen.. rt? nee secwanes Omer eeeenwcecerene Sufenstreients o^ en TT Sufenstreients identc .ee cence rt ee Chik Chik ....... ....... Tow wet hee eae ececeenarcancy of Number Number Workin i MAC Dust moc- tras.on Lakes CAPPOT 1 ' . . s * cu 4 rs ' 13 : . 6 * Harley 26 74 74 = naa oy 7882 7882 - . 258 5 fg 3 ae : 7882 258 sere 7750 3 2 7750 | 1 7750 > >: 7750 2 % 3. \ 4 . | ! H { = { : 6 i 10 4 : 6 1: Vhewe 3 ... " 3 fa. fa ace, s a A al > Bode 3 3 i 1 ; | 4 3 i ... Vi 1 t : . > 4 t PY 1 : ! 2 3 \ bl 2 Wl = " 2 ae ls ae 3 . ts: 1? 1 Ju ae ao 3 1, 24 ee samples similar similar P^/rast isme^-es obstra^-ostus 9 Fin Fin Fin Fin samples of other setup in asarani activities siysi PLINPUT The chemical and determined from petrographic both analyses of dust samples were directly from the settled dust samples and samples obtained air by means of a ferences in vacuum cleaner composition were noted between No great dif collected by these two corresponding samples samples methods Total nsh was percent for all the samples No free silien 77 approximately petrographic analysis quartz could he found on Particle size determinations of three methuls namely namely 1 with a Owens jet samples termining the ratio of fiber to ensempe projections particulate matter 2 were made by device if^...rde by means of " photomicrographs micrometer micrometer attachment microscope microscope measuring measuris measuris sive micrometer matter 3 with photomicrographs particulate length fibers fibers study fibers fibers particulate matter showed that the ratio of pe- pe- cent particulate varied considerably maximum crushermen crushermen Ti weavers a minimum minimum percent percent 2% pe median particle ( exclusive fibers was approximately approximately Ti microns median median length was 16.3 inicrons 1 distinction could made varied from asbestos asbestos fibers fibers microns. \ made between control asbestos dust hazard In most the plants plants studied control exhaust systems systems limited almost entirely provisions provisions exhaust the cardin Ww: machines Data however indicate the effectivenes effectivenes effectivenes with which the dust available handled handled asbestos asbestos textil problem employs handled use hoods hoods exhaus plant An effective method producing source source Data showing showing teh xhae us equipinent fitted each each effectiveness of producing table 20 showine ti, exhaust equipment presented presented in tu bile tu bile Table roiled 20. mmary controlled and uncontrolled irmiking irmiking cunditions cunditions wailer controlled anid WACOM eosding cUNnditignr ty tite Mande, Equipment . Wil owung Piling Willowung opening Piling Pickine so. . caemonensecnnce ne ooo CPaircdkiionse Irving pool Irving | on . Weaving Steromel lames Pruner celenuerer. . tees ecccend comment Exhausted his comment encarried connec othe connec twons 120 1! a. a o sue z3 UFM UFM of w' ore 7 Perert coy. sate el La Sarees wun een sMEPU PF 2.370 oe 120 HO D 1 1.A'O 1.A'O 1. Dae bag si. fu aes 2. 0 34 bd ty Tere e owe ewe, Oe Oye 1-0 Milew. 4 17 3er4 -. ve n ' lean i asbestos asbestos industry can be greatly asbestos necessary control methods reduced reduced developed further are now in the With exception methods been developed developed concentration- concentration- concentration- exception pickers are controlled controlled ooffexposure6.7 million particles per cubic foot kept conditions conditions ir particles exposure other below million per cubic foot It occupations occupations be improved methods ventilation to reduce even the possible exposure picker's picker's improved less than figure figure indicated tu The following commendations exposure made metlanls of veuttlartee removacomlmendations concentration The Dust controlled the point of origns by minanes " controlled Jocul exhmust exhmust hoods and operated to reuch breathing breathing ddeevsiiegrnsedwhiwocrkhers workers to contaminate contaminate die genera a capable capable Ho air Dust deviers 2 of restoring dus age. level million particles particles cube or lower have been for developed developed operations operations the asbestos asbestos industas industas ( ) for operations "UPAR textile Hovelupue| for g I eles per cule fol oF fern (7)athe MIN Petia. Ite Che aebestos textole tadizeryss