Document wgx9RZ5KJLk31nDEYevo0Y4MD

FILE NAME: Texaco (TEX) DATE: 1935 DOC#: TEX005 DOCUMENT DESCRIPTION: PA Dept of Labor Bulletin - Asbestosis Part 2 S S fi j ^m i s i i j f (M ife . Special Bullet** 7}o.42 AwS;Bu .E* ~ST OSIS -P arc II- ttt P aIt The N u rc a n d A m o u n t E n c o u n te re d J n A u b e u to s la b n c a r - ing P lants. T h e Effects o f E xposure to D u st S e v e r e d d u A u b e sto s^ a b n c a .- ing Plants o n th e H ealth o f * o f W orkers; STANDARDS uBtUrnREEAAUU jOohFnINCDAMUSpBTERtLIA, DLir^tor (i * i y y. f . X > x -* H arris*** Pennsylvania September 20. 1935 r' ' . - : uvV** . V? " * w a i^V * * * ISM TO* 3 & r C4* : ij- ! Hi | i )ii 4t X _ \ _ _________ ___________ v V" . > COM MONW EALTH OP PENNSYLVANIA D epartment of L aiior and Industry 1 I * I I Part II. Part III. " I * t Asbesto$is i The Nature and Amount of Dust Encountered in Asbestos Fabricate ing Plants. lt The Effects of Bxposure to Dust Encountered in Asbestos Fabricate ing Plants on the Health of a Group of Workers. i W illiam B. Fulton, M. (., Chief of Industrial Hygient A llan Dooley, Chemiti' , J u lia L. M a t t h e w *, Ph. p . , Chcmut R o b er t L. H o u tz, CJiemijt i X 1 INDUSTRIAL HYGIENE SECTION ni 1 n a11 ah t kins rocrn i av an*avm an r\<* I IA ^ 7 Z , :7' ASBBSTOSIS--Part II. The Nature and Amount of Duit Encountered in Aebestoa Fabricating Planta.' 1 NTKODUCTION f lii IW (lie Department of Labor and IndUHtry of the Ciiimmm- wealth ufl'ciiiisylvniiiu received a request for Informtico relative tu (lie licnlllt t workers employed ill asbestos fabricating plants in Pennsylvania. The Department had no data available, and a review of tlie lilernture nt that time revealed a scarcity of information on the general subject of asbestos pneumokoniosis. Because of this lack of information, the industries in the State were consulted, and their cooperation was obtained to conduct a survey,'which would include an evaluation of the hazard from the standpoint of the de gree of dustiness and the physical condition of the workers. An agreement was made with the employers and employes that neither would be given specific information as to the physical find ings of any particular workman, and that the original identity of all employes in this study would be destroyed, case numbers only being recorded. All records obtained were to become the property of the Department of Labor and Industry. Asliestosis was first recognized clinically by Dr. H. M. Murray (16) at tlie Charing Cross Hospital, London, in 1900. Cooke (16) in 1924 reiKirted a case of pulmonary asbestosis. Pancoast and Pen dergrass (8.1) in 1926 examined a group of seventeen asbestos work ers. Since then, other investigators have reported individual cases of ashcstosls, but it was not until 1930 that Mcrewetlier and Price (74) published the results of a study on a group of asbestos work ers, together with some evaluation of the degree of exposure. Lanza. McConnell, aud Pehnel (66) have recently published a preliminary report of a comprehensive survey oil this subject. The Industry ill this State consists mainly of several fabricating plants engaged in the making of asbestos clothj brake lining, in sulating tape, asbestos rope and wick, and other miscellaneous prod- nets. According to the 1931 Pennsylvania Industrial Directory (61) there are approximately two thousand persons engaged In the manu facture uf asbestos products in Pennsylvania. The nature of asbestos dust is such that many of the standard procedures used for other dusts eouid not be used. Changes in the accepted standard method were required in the collection, count ing. und particle size determination of the dust. In Part I of this report (41) the method of collection and counting of dust en countered in this study was described and summarized.* KMHMlm o l iliul U kr* U plants lor tatiikallns aabrtlea pradurla v u * ealWUil t>r i MtallHAl Im m *1 tb r M m lk itl utrlUoU, lultig * it* I*r ( m l U V I. tlliyl ulrobol hr iitnUuitta lit IbU intoItutil lit M rtW n i n well tiUliUwlrd bml ifmllljr rmtuinl* Wkr tlMIIM tn tlrr k m ulMImt ** lb* rttllrrllltg lanlUmi, ugtfWwtritlbtu om irivil htthtnliaUIjr. mi| until* mmutluv bu|oalb|f>. ltU|*tUi*t u l lit bul tu alr4t*t U ipmmI* A MtlUu^jANte ni I b u t Ib lrlr mluulr h imulreU M a r touulbtg. *rb* ttu rllrk u tin i lu i t ^ B n rlil rnualonl rm trUttl Her llito itrftotl* A motllfinl boWlrr I Im rlU tl. II I ul leallirr i l n i , lu aurb i f lk * t lb *uM bt ib Uupktgrf Ih tk U UlUle al U luH^T I Preliminary lu llic collection o atmospheric dust samples in each ut the four plants included iu the survey, general information was uUlatnvd concerning all phases of plant hygiene, with special refer* encc to the general plan of the factory, number and types of opera* lions, ventilation of workrooms, illumination, etc. . The concentration of dust in a plant was determined for each operation or department. A complete study of each operation was made, noting iu detail the nature of the work, approximate time rc* cpiired for each operation, and changes in the process, so that sam ples collected would be representative of the actual exposure to uust P roperties op A sbestos The term "Asbestos" in its commercial sense is loosely applied to a group of minerals with a number of sub-divtsiohs'hkvuig, in com mon, fibrous structure, and possessing more or less resistance to the action of fire and acid. The three mineral groups are:' 1. Anthophyllitc--(Mg.Fe) SiO,. 2. Amphibole or Hornblende--Silicates of Fe, Ca, Mg 3. Serpentine--3Mg0.2Si0t.2Ht0 . The three types of asbestos ordinarily used in manufacturing ore ciirysotiic, crocidolite, and amosite. Crocidolite (blue asbestos) and amosite, a yellow or brown variety of crocidolite, both belong to the amphibole or hornblende group. The principal source of the latter two varieties is, at present, Rhodesia, South Africa. Chryso* tile, a mineral of the serpentine group, comprises the bulk (about US$*) of the asbestos of commerce. Only relatively small amounts of crocidolite and amosite are used in comparison to the quantity of ciirysotile. I The principal source of ciirysotile is the Tiictford region of Can ada, about forty-five miles south of Quebec. The United States docs not rank high as a producer of asbestos, the domestic output being less than three per cent of the amount used in its asbestos manu facturing industries (10). No asbestos Is mined in Pennsylvania, although small amounts have been found in serpentine quarries from tune to time. No attempt has ever been made to separate the asbestos from the serpentine in there quarries. Arizona and Ver mont supply the bulk of asbestos mined in this country. TAm,K 1-TV rlO A I. AMAI.YSKS OF OUBYSOTILK Kainate So. 1 ...... . s --------- T8o10Ul M.M* tt.tt M(0 ---'-F--tiO-.--- % *!% 42.19 ' Ut AI.Ol 1.07% 3 ----- --- 4.4I 4 ........-- 39.22 ( 49. Ml 1.0# m.w 9 - - - .... Ml 1.0 .17 UM 1.07 . 0. . *. l.M Ml 1.00 . 1.00 *.t* 0.01 l.M 0.0# . S.00 I.M OUoin.Ob. *.* M.S0 11-17 K.I7 11.SO 11.00 11.17 ^ IMS ^ Iii ill Canadian deposits the clirysotilu is found in wins (rum uc-eighth inch to six inches in length, occurring es bauds in life. M-r|u'iiliiic rock. The mineral is generally a dark to blackish-grccn . hislruus color, although when the fibers are separated iuto fine lilmiiciil*, they are white. The fibers are very fine, silky, soft, grwisv mid slippery to* the touch. They cannot be separated into a single liber like cotton or wool. riicuiinilly, chrysolite is a hydrated silicate of magnesium with Muall amounts uf oxides of Iron and aluminum. There arc many published analyses of chrysolite from the Thetford region, and tln*y appear to vary but little. Table l gives eight typical analyses ( ciirysntile (95). The silica shown in the analyses id Table l dues uni exist as free silica. It is chemically combined witli the imsi-s in a cumplex molecule. Samples of dust collected in the workers' breathing zone with the electric precipitator (30) were analyzed petrographies!ly and were found to contain no free silica.* 'I'll chrysolite of commerce is classified in two general grades, depending on the length of the fibers. Crude fiber consists o( the liniul-separatcd and selected material essentially in its native or imlihemcd form. Mill fiber includes ail grades that are obtained by mechanical crushing of the rock and subsequent mechanical sep aration of flic fiber. Crude No. I consista of fiber whose length is inch ami longer; Crude No. 2 ranges in length from )( inch up to Inch. Mill fiber includes ail fibers less than )( inch in length. The spinning quality of asbestos fiber depends primarily on its length. Consequently, the best grades of asbestos textiles are made from tin*, crude fitter. The shorter fibers arc used in cheaper grades ' of textiles and in the manufacture of asbestos shingles, paper, plas- ( ter. mid cement. DnscaimoN op P rocess Preparation--Crude fiber aa received from the mines lias under gone no treatment other than hand-hammering to remove the rock from the fiber, after which it is sorted and screened. It is received at tin* plant in burlap bags, each containing one hundred pounds. ' Tin*, filters must first lte separated aud loosened to rcuioee rock par ticles. This operation is done in what is known to the industry as a "preparing room." A number of baga, sufficient for one batch, are o|tiicd and dumped on the floor of the preparing room. The filter is fed iuto rim-wheel crushers and crushed for about fifteen minutes. These crushers have two heavy rollers attached to a radial axle, and revolve on a smooth surface on which the asbestos Is placed. After the fibers have been crushed and loosened suffi ciently. they are fed into the hopper of an opener or iiberizer. ustiuUy uf the Saco-Lowell type. This operation serves to further open the fibers. From the opener, the asbestos is discharged onto a rectangular shaker screen where small pieces of stone, foreign iiialcrlnl. and some of the dust arc removed. The asbestos is lifted fmiu the screen by air suetiou and conveyed to storage bins, ft is Own ready for mixing with cotton. I I IikiItvminwlr.aliMailiri lirwrl,fMl*rac uaIi)lralutinidnraDwerprarnteatutaHlicaIrt tlLharb oDrr.t akd, K. Qalloaa, Ia<lutr. | JuiliU) Mill filler. because of tlic mechanical entailing and separation given it at the mine, docs not require the preliminary processing hi the rim-wheel crushers as docs the crude fiber. Tlie mill Alter is led directly Into the Saco-Lowell opener, and from then on is given the same treatment as the crude filter. Asbestos filters when examined microscopically do* not possess tlic rough imbricated surfaces of other fibers sueu as tvooi. They resemble fine polished metal rods, free from any serrated surfaces. This characteristic explains the extreme difficulty encountered in attempting to spin a thread of pure asbestos. A certain amount of cotton must Itc added as a bind} for spinning. The amount added depends on the type of filter and the use for which the finished product is intended. Tabic II sliowa the average amount of asbes tos used in the inuntifactnrc of products made in the four plants included in this survey. TAIU.K II-VKHCKNTAIIKH OP AHUKHT0H IN VABIOUS AHDKSTOI PBODUOTS N tliriri M ast A M ast H M gu Maul D lin k * llulu* (w o rn ) .......................................-- MW -- luaulalloc Up* ------------------------------------------ -- 1 Atbralo* cloth ------------------ -------- -------------- U-M m Cowmcrchl anti* p*is ----------------------------- - Oor*(. Uprd f. yarn ami rlolli -- M Aaltealoa >vp* Uwl trick -------------- t ------------- O H M * Vara and d o th . UmlcrtuU* Spec. ---------- -- -- ai-M AbnlM cviwraU -- -- llrakc lining (inoMnll . . . . --------------------------- -- -- Aalmloa paper ______________ ____ -- -------- . . ... K% utacnnla Inaulallon ....................... - -- .j -- -- . Aabraloa ahln.lca and hunter ______________ . . . -- CoMpIkil (rum lulnruiatloa atipplM by Um ntcnularlureia. 1M ** m -- ~ .. -- IMS IP -- . .. 0% KH IO-IDO M-WO -- -- -- -- M ii Mixing--Weighed quantities of ksbestos and cotton,'and usually some small amounts of card waste, are dumped in alternate layers in a pile on tlic floor of the mixing room directly in front of the mixing picker, 'flic batch is shoveled into the picker, which is equipped with revolving beaters. In order to secure thorough mix ing, tlic batch is run through the same picker twice, or through two pickers arranged in series. Tile mixture is removed by suction to tlic storage bins to await caruihg. Carding--Carding is necessary to remove tlic remaining small bits of rock, and to comb the fibchi into a more or less parallel con dition so that they may be spun. -A card is a machine witli a series of revolving cylinders covered with strips of Icathcf, wound diigounlly, and fitted with fine, close-set, sharp steel bfistjes.. A cardj ng unit, ns used In asliestos plants, usually consists of two cartfl die breaker and the finisher. The mixture of asbestos and cottJI ) I U irlivclrd in hand truck from the storage bins, and fed by hand bin the (red hopper of the breaker card. It is passed over the re volving cylinders of the breaker card, emerging in the form of a |(wise blanket or web. The direction of flow is then changed ilirungli ninety degrees. It next passes over a camel-hack into the finislier card. The filler is stripped from the last cylinder of the finislier onto a moving leather apron where a set of reciprocating wiper* or rubbers condenses it into loose rovings or "slivers" of unspun yarn. These rovings arc wound on long Jack spools to be in.krii to*the pinning department. The rovings at the extreme ends of the cards eamiot be used for pinning pur|Mie because of their lack of uniform thickness. These are gathered no as card waste, and, together with waste frurn snhM*pient operations, returned to the preparing room where the waste is shredded and added to later hatches.. Some cards are designed so that a fine cotton thread may he inrnrporntrd into the rovings as they arc doffed from tile card. This practice yields a stronger roving. . In the manufacture of asbestos rope and wick, only one card is lived. The rope and wick rovings, which are not subsequently spun, are thicker than yarn rovings. Hence, one earding operation is suf ficient. Ccncrally a fiber of shorter staple than that used ill textile innniituclure is used ior making rope and wick. Spinning--The unspun rovings, as they are doffed from the cards, ncccvsarilv have no twist and therefore little tensile strength. It i- necessary .to.twist or spin these rovings to impart the desired 'iri-nglh. This spinning may be done either on ring spinning frames >r on a machine called a nude. In the plants included in this study all the spinning was dune by the latter method. Several of the plants had spinning frames, but thev were not in operation. The mules had from two hundred and sixty to possibly five hun dred and fifty spindles mounted in a straight line on a carriage which is made to move forward and backward. The Jack spools from tin* card* arc mounted on the mute and ttic ends of the rovings (asiciii'd to the spindles. As the spindles recede from the Jack s|hhi|v (n maximum distance of about fifty-four inches) the rovings are unwound. The spindles turn slowly as they recede, to give a 'light twist to tltc rovings. When the spindles have reached the point of greatest recession they arc turned very rapidly, and the yarn spun. When sufficient twisting lias been done, the spindle carriage moves hack n>ntin in the direction of the Jack spools, caus ing the spun yarn (about fiftv-four inches) to be wound on the vpimlies. The operation is then repeated until the spindles arc fnllv wound with single-ply yarn. The duties of the mule spinner arc to remove the spindles from lie mule when thev are filled, and to tie the broken ends of the un-pint rovings as the spindles recede. This last operation requires eouviant vigilence. because the rovings arc continually breaking. Subsequent Operations--The sniiidlcs from the mules arc next transferred to n spooling or winding machine to rewind ihj^^hglrplv yarn on oilier types of spools. This is simply a mi^PRical transfer of the yarn. \ J These spools are next taken to a twisting: machine whert two or tliree of tiie single-ply threads are twisted Into one thread. F o r tin* manufacture of brakd lining or packing the yarn may he re inforced with a flue metallic wire. This addition fa performed dur ing the twisting operation.. The twisted yarn Is finally wound on paner spools about six inches long. The twisted yarn may he sold ns such to other manufacturers, or it may be woven into cloth, tape, or brake lining, or braided In the nine plant. Weaving--Weaving Is done on looms in a similar manner to the ' . method employed In weaving wool, cotton or silk. In the weaving ( asbestos tape intended fur electrical insulation, single-ply yarn . j with a very low coturn content is used. Most tape looms are con- straded so that as many as twelve pieces may be woven at the j same time. It is the usual practice in weaving asbestos tape to wet the bobbins or "cops" with water before weaving. The warp is kept dry. Cloth is woven In much the same way as insulating tape! Two- j nr three-ply yarn is used. Sometimes the yarn is'relnforced with metallic wires, generally brass or copper. Either or both the wnrp j and All are dry or moistened with, water, depending on the use fur which the cloth is intended. Brake lining is woven on looms in the same manner as tape. As 1 many as eight pieces may be woven on one loom at the same time. It' may be woven dry or wet, or with the warp impregnated with a "dope" solution. This solution is generally a suspension of gilsonite in pasolinc to which other ingredients may be added. Final operations In the manufacture of woven textiles consist of calendering, inspecting and winding o f the products. These opera- # ' lions are all mechanical ones, and require no description. Gasket Making--One of the important uses of asbestos cloth is in the manufacture of ring gaskets. In this process, the asbestos cloth is spread on the floor and Impregnated with a solution of rub ber In gasoline, to which has lieCu added barytes and other' pig ments. The rubber-treated asbeijtos cloth is rut Into strips of nrc- ! determined size, and the gaskets formed by hand. They nrc then coated with soapstone, calendered and packed for shipment. An inexpensive gasket and parking is made by twisting thick rovings into asbestos wick and rope. Still other types ol packings arc made by braiding asbestos yarn on specially designed machines.' O tiikr P rocesses Other products containing asbestos are made in some of the plants included in this survey. These products include asbestos paper, in sulation for steam pipes, asbestos cements, shingles, lumber, molded brake lining, and euld molded asbestos articles, generally elcetrieal fittings and household appliances. The fiber used for 'these purposes lis of short staple. Tim percentage* of asbestos used In these 'tides is indicated iu Table II. P akticlk S u k Determination ( M e and Hill (22), In autopsies of asbestos workers, have found particles in the lungs measuring up to lhrcc( hundred ami sixty microns in length. Accordingly, m the determination of the average particle size of asbestos dust, all fibers, irrespective of length, were measured. Methods of Particle Size Determination--Within recent years Ilire general methods have been nsed for measuring tier size of particles; One method, a direct one, involves the use of the filar micrometer inserted in a microscope tube, Measurements being made by moving the micrometer adjustment and rrnding the vernier to determine the diameter of the particles. The second method, an indirect one, was introduerd by tlrccn (55) to determine the size of paint and rubber pigments. It has since been applied to the measurement of the average size of in dustrial dusts. In this method, an indirect one, photomicrographs of the sample are made on lantern slides, which are then projected hy a stcreoptiean on a screen at a known magnification. *fhe images are measured and the average size calculated from these readings. . With the third method, the dust is collected on a microscope slide, and the images projected on a ground-glass screen with a ndcro-projcction apparatus, and measurements made. This latter method is the one used in the present study, mid will he described more fully in a later paragraph. Nature of Asbestos Dust--The dust encountered in asbestos fab ricating plants Is non-uniform in nature. It is seen to consist of three types: particles more or less spherical in shape; elongated filters; and cotton fibers. Figure 1 is a photomicrograph of dust pro- Vf- lured when processing mill fiber. 'Hie three type* can be readily noted. . lUraiihc of the n*hi-iinif*riitity of till* type of dust, average par ticle size was determined in tw o dliucimoiia, ouc at right angles to tlie ntlier. Mcnsiirt'iut'iitK were made of ttie longest diameters, whirli were termed longitudinal diameters, and a second -set of measurements were made at rigiit angles to the first, which were termed transverse diameters. Method of Collection--Samples for* the determination of particle size were collected by the use of the electric precipitator (30). This method yielded samples that were satisfactory for direct micro- projection and measurement. No intermediate steps for preparing the sample were necessary. The precipitator employed was designed on the principle of the Cottrell precipitator, nie air was draWii through the precipitating tube by a small rotary fan driven by a motor, the rate* of flow being measured by a flowmeter. The rate of sampling was one cubic foot (28.3 liters) per minute. The precipitating tube was made of Pyrex glass with an inside diameter of 2.4 cm. A number 1 microscope cover slip, 22 by 20 nun. in size was placed in the precipitating tube directly beneath the central electrode. The dust In the air was deposited electrically on this cover slip. When a representative sample had diccn precipitated, the cover glass was removed and mounted dry oh a microscope slide. A total of sixteen samples yvas collected at various operations, ail being taken in the breathing zone , of the workers. 1 Measurement--A micro-projection apparatus with the microscope arranged in a horizontal position was used. Apocliromstic objec tives, 8 min. and 2 mm., and a 10 x compenaallng evepiece were employed. This system practically eliminated color fringes, gave a flat field, furnished maximum light intensity, and permitted , the measurement of the long^ fibers. , : . The images were projected on a ground-glass screen at a pre determined distance from the microscope. This screen was ruled in centimeter squares to facilitate measuring. A transparent jrulc was used, and the size of the projected images recorded in n illimeters. Accurate focusing an each individual particle before m :asuring was accomplished by a remote control attached to the finc adjustment of the microscope by a mechanical sleeve. Predetermined magnifications of 2000 and 10,000 were used,! dc pending on (lie objective. Measurements were made according to tlie method suggested hy IT. L. Green (56). Using the 8 mm. ob jective (magnification 2000) the longest diameters of two hundred particles were measured, all Icngtlia less than ten millimeters (five iiticrims) being neglected. The number of fields examined was also recorded. An equal number of particles was measured using tlie 2 nun. objective (magnification 10,000), and all particles fifty milli meters (five microns) and over were disregarded. Again the num ber of fields examined was recorded. These measurements were used to calculate tlie average longitudinal diaincTcr of the sample. The method of calculation Is shown lu Table III. For the calctilali'^ M the average transverse diameter the saute procedure was i J follmml, tilth iia-nHiirciiiciits being made at right auglex to the hingcxl liniiictcm. h TAUI.K. . . Kx' A'(rK !5a u AU!uut,on w l l a i t M u l l w - M I iW PlalOa Mlsa lle a l ton--10,000 V rk M i 1 i. . i. * u u I 1X II i Mi> 11..11 aM -I.M0II .0301 I.UOTC 1.10330 94 00..31 a91i l.ll l.l* ! IMI 11..10 .10311 .11300 .>10 I.IIOIt o.otuo t.OUSO I 00..10 310 I.M 1 0.1 ft. IS i IIII 11..11 II 1.1 .01311 ' 1.305 .03111 I.3 U II Ift 00..00 1t01 ft. ft.W ft.Uft 1 MMII 1111..11 .M3I0 .MUI mu t.tlaco MUCO 0.11? I1f1t 11..10 19 1.1 u1 1 4t.JO . I.* II IIII.. II I l l .0011 1.10101 6 1.1 .c c m l.lo ill . tft ft.ft I1I3 *.| .14 ftl.UI InI 1111..11 i* II. .03111 .13011 .m u I.1II0 O.UOOO I.4I1C1 19w1ft t1..1l 1.0 f3t l.fiw ft.ftft 1 to Ml 1111..11 II 11.1 .m u .m u 10130 .1*10110 I.IWCt i.Msoe 94f3t 11..10 a 1.1 1 ftl.fc ll.ro 11 . 4M O - Id 11.1 11.1 mu .1093 .n o n 1.11111 Tola .J S*a aa .ui II .m u mu O.COOJI a.-- *.11131 ---------------- a ii.* 9ft 1 1 .00030 .00030 1.303)1 1.30301 KM. I^U (tb u l Imagr lu HlUUuM'lrrv 4ft Ml 41 1.1 is .0006 MIMO 1 .m u I.OOflU H ' l> (lli ul o alllfk lu wlrtmi. i : a II.I IS U .I t mu 1.113)3 1 (UOli 1.33)01 I - Prrqucurr a Ml to 16.1 1 .m u 4 .n a *.1)001 MliUO . I * I I u 114 ft U .I f1t .10311 tocio i .10113 *.10000 It I-- I (*) o II.1 tilt US 1 .m u .loen I.0U13 I.IS0S3 ... X I I * Ml + S ilt a Ml I n n i a fitouM rr ------------- ---------------- ii .I 1ft .ft ) mu 1.11003 .10600 ft.OCIU X I + X li ii 90. M 31.1 1 m is 1.30001 | 00031 *.0030 " 1.D fttlrrona. 0 U .I 14 41.1 I .00030 I.003U0 1 occso 3.117)0 M u .i 100 0. mu .m u 1.1** 1.10)00 no .ft iso ' ttO.ft 1 .11300 .0931 l.tlMO i.oenoo iso .ft no lo.o 4 .11200 i.oiooo .00034 I.VIIOO liso (0.1 no os.ft 9 .oooit 1.00000 I mu 1.1)111 i n .i IfO 0.0 | mu f.MCft | mu i.lloco too MO.* no 1(6.0 1 mu mu 1.11000 I.IW Ii I I 1.10 i i i .i t.a 131.1 | mu 1.11333 . m u 11.0X00 !U 131.1 lift ltt.0 1 .0931 (.9um mu I.IC0U 970 Iftl.ft t mu 0.1311 Total MO .MOCO i l l . luna i.R |SU,i*--n ar.t c. c *izc .`lctcitiliiatioiis were nude on mimics of the dust collected nt various stages in the process of manufacture iiiirrih. edI d`iiliicrernc1e'1:in the averagwea*|nirwU,,c,l,,cLdia1mloeitveervorrf. thIelndrcustn Aa ^ tu two general grades of asbestos fiber. The calculate.! PERCENTAGE tndinal diameter nC ilic dusk from crude fiber was found to be 2.12 microns, wldle that of. mill fiber was I.3S microns. Transverse diameters were 0.69 microns .and 0.45 microns for crude and mill fiber respectively. The'longest fiber observed measured (our hun dred ami two microns. Tile percentage frequencies of the various-sized particles were determined for longitudinal and transverse dimensions. Figure 2 shows these values plotted on Hazen's logarithmic probability paper.. The difference in the two types of dust is further shown by ex amination of Table IV. Three per cent of the crude fiber dust was ten microns or more in length, while only 1.7% of the mill fiber dust occurred within these limits. Twenty per cent of the mill fiber dust was 0.5 microns or less in length, while only 16% of the crude fiber dust fell within this range.. TAIII.K IV. SISK VUKQUKNUY DlKTaiUUmOH O r ASOBSTOS OUST OomIon tor NIU ruxe LobsIIihIIm I T r u m m Uttdw S.tt ----------------------- S.S-S.M -----------------------------1.1-1. ___________. . . . . . . . . __ 1.1-1. ---------------------- ----- t . e - t . u __-- -------------- ......... i.r -i.n ............ -- ---------------I.M.4I u a.iu . . . ______________ ___ 4.M.W ,_______________ : .... i . 80 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 uil o vrr------- ----------------- SI.V& St.l l.t 1.1 1.1 8.1 1.8 1.1 1.1 1.1 1.1 M.l% M.I i.i i.< i .i *-- --- 1.1 I w i M l o l Trnmff 41.VJ 11.1 1.1 1.1 1.1 1.1 I.I 1. 1.1 1.1 1.1 n .r; au.a .1 j -- ( -- .... . .... .I D ust Concentrations in tu b P lants Ali samples were collected by the modified form of the GrcenburgSmith impingcr (58) using ninety-five per cent U. S. P. ethyl alco hol as the collecting medium. Dust counts were made according to the method described in Part I of this report (41). All particles were counted regardless of size. Particles less than ten microns in greatest diameter averaged approximately niiiety-scveit per cent of the total. The dust counts for the different operations are shown in Table V. TABLE V, KCIUIAKT 01" DCST OO-VOESTKATIOSK IS ASBESTOS FAIMKMTIStt fLAKTs 14 Ttic relative degree of dustiness in the various departments of the four, asbestos fabricating plants surveyed is indicated in Table . VI. Tills HUininary of the average concentrations from the different' plants has been prepared from the data contained in Table V. TAIILK VI. RKIATIVE DUST OONORNTnAlfOMS IN I>K|-ATJIKN1'8 O r abukstos r u u m Tkt|artHMUl Number o! Bamplca CenctalrallAa--Nllttons 1 r i r l k k t ^ t r Cubic Pool u | Air Minimum UaxIiAum Averts* riep irn llo n sad Cardins ----------- --- ---------- --- u M IS3.J V favlas and Slula Bplonlo*--------i----------------- 1 I. .s W.H TajMIng, V luillm , Uopa aad Wick, UcaUlas. *.* 1 .1 It will be seen that the highest dust concentration occurs in the preparing room, where the asbestos receives its preliminary treat ment. The lowest concentration is associated with the making of ring gaskets. The figures given in Table V I. while showing the relative dustiness, do not explain fully the conditions in each de partment. The concentration of the dust In the successive phases of the process varies, dcpending'on the type of fiber used and the method of manufacture. In order to explain these variations, it is necessary to discuss separately, conditions encountered in the sev eral operations. The figures given in the following paragraphs rep resent the concentration of dust in millions of particles per cubic foot of air. Preparation--The dust in the preparing rooms is practically all due to pure asltcstos, no cotton having yet been added. Th de gree of dustiness depends primarily on the type of fiber used. Thus, it was found in plant II that when mill fiber was fed into the SacoT.owcil opener, the average couut was 119.4, as compared to a cou. centration of 33.2 when the longer-staple crude Alter was treated in exactly the saute way. In plant I) one of the operations involved the screening of shortlength mill fiber without first passing it through a Saco-Lowell opener. The employe engaged in feeding the material onto the screen was found to be exposed to a concentration of 65.7. A sec ond workman, whose duty was to fill burlap bags with the screened filter after it had been removed from the shaker by suction, was ex posed to a concentration of 96.1. In the mixing room, where the cotton and asbestos are Mended, the degree of dustiness' was again found to depend primarily nn the type of filter used. For example, the concentration of dust was 10.6 when a mixture uf cotton and mill filter was being fed Iflh the mixing picker. The concentration dropped to 3.1 when th c ^ ^ tu r r 1 . 4 ' was made iron crude No. I fiber. In plant D, when the lowest grade i mix u-as fed into the picker, the concentration was 84.7. Carding--The marked difference in tlie total dust couiit in the carding operation as the result of using different grades of asbestos will again be seen. When the crude fiber mixture is being carded for the manufacture of electrical insulating tape, a concentration of l.l was noted. The mixture for cheaper grades of yarn, such as that used for weaviitg brake lining, is generally made from mill fiber. The concentrations of th dust when mill fiber was being carded were 23.4, 24.3, 29.8, and 80.0. The samples were collected in card rooms of various plants. Occasionally the loose web of asbestos and cotton, as it emerges ! from the breaker card and passes over the camel-back, becomes broken. It is then the duty of the operator to go to the rear of ! the card and repair the broken web, the task requiring approxi- j rnatcly one-half hour per day. It was found In one plant that the j employee was exposed to a concentration of 57.5 during this time, while during the remainder of the day he was exposed to a con centration oi 24.3. At intervals it is necessary to shut down the card and clean or "strip" the rolls. This is done by scraping them with a hand-card, which is a brush covered with strips of card cloth. The cylinders are slowly turned by hand at the same time. The dust concentra- . lion during this operation was 5.5: Sometimes the rolls are cleaned while they arc heing turned at the customary carding speed. The ' employes'stated that this was a very dusty operation, but it was impossible to obtain samples during tills procedure. ' Weaving--The concentration of dust in weaving is dependent on f*' many factors, but principally upon the following: (1) quality of the warp and fill being used; (2) whether weaving is done dry or wet; (3) conditions of ventilation; and (4) nature of the finished product. The influence of the first factor is shown in the weaving of in sulating tape and brake lining in plant C. A concentration of 6.9 was associated with the weaving o f tape (made from crude fiber). In the weaving of brake lining made froth mill fiber, the count was 27.1. In both of these operations the warp was dry and the fill wet. As pointed out in the description of the weaving process (page 8), weaving may be done cither with the yarn dry or moistened with i water. The presence of moisture materially decreases the con.- j centration of the dust. For example, in the wet weaving of brake : lining the concentration is 6.1, but when it is woven dry the count ( increases to 27.0. The effect of ventilation Is shown in the weaving of cloth In plant I). In this plant, ordinary electric fans were located just hack of the weavers, so that dust generated In the process would he blown nway from the worker's breathing zone. When the fans were operating the concentration of dust in dry weaving of doth forty ` indies wide was 9.9. When the fans were turned off, the figure rose to 33.3. kThc fourth factor, nature of the finished product, also Influences^ c degree of dustiness. Tims, the average concentration ci 16 I / ) countered iii weaving insulating tape was 10.5{ that of doth. 21.3; mid ii( brake lining, 23.0 The httinis in time accumulate a great deal o( lint. This is re- . moved periodically (generally once a week) by beating the loom with a llcxihle rubber paddle. Each weaver deans his own loom, tile lime required being approximately one-half hour per week. Unring this operation the dust concentration was 74.1. Spinning--The concentration of dust in the mule spinning room depends on the type of asbestos fiber used in the making of the yarn. A count of 2.1 existed during the spinning of yarn made from crude fiber for the weaving of insulating tape. A yarn made from a high grade of mill fiber produced a concentration of 5.5. The dust associated with the spinning of commercial grade yarn, the cheapest grade made, was found to be 13.2. These figures are for the mule spinning in plant B. In plant A the average concentration to which the mule spinners were exposed was 23.0. In this plant all operations from preparing to weaving were carried on in the same room. Consequently, it is Impossible to state that this con centration is due to mule spinning alone. Other Operations--The minor mechanical operations necessary' in the production of asbestos textiles have relatively sniall concentra tions of dust associated with them. In thd winding operation in plant A this was found to be 8.0. Again, this number cannot all he ascribed to winding because of the fact that all operations were performed in the same room. In plant B, in the twi&liug room, a figure of 2.4 was found associated with twisting two-ply yarn. This figure increased to 4.0 when yarn was twisted three-ply. Warping is a mechanical transfer of the twisted yarn to large spools or warp beams for the looms. It gives rise to very little dust, the concentration being 1.0. D ust C oncentrations in O t iie e P rocesses In addition to the fabrication of asbestos textiles, one of the plants manufactured other producta in which the amount of asbestos was considerably less than the amount used in textiles. These products included 85% magnesia insulation, molded brake lining, asbestos cements, shingles, lumber, mid tile. One plant made as bestos paper which contains ninety-five per cent of snort-staple mill lihcr. Determinations oi the dust concentrations were made at some of these operations. The results are shown in Table VII. Other Potential H azards This survey was concerned only with the hazard caused by ashestus dnst, hut other materials that must he considered as potential hazards were found. These materials are gasoline and benzol in the gasket mid molded brake lining departments, tajc dust in the gasket riNiiu. and lead compounds in the rubber mixing department. In the finishing asbestos lumber and tile, additional potential hazards are iiu-quer solvents and sand from the grinding and po lish er ,mraiiiiiis. 17 i .. ! i 1 ! Vi, - V . . . . taiii.k vu. hush' ciNi'kxi'iiationh or uihokm.ank<hia opkuayIukh ih ah I . ANIIKVniM 1`kAMT Ik-plllnmil Uprratlon Number ol Allupici UflBceotritloo Is MIHIotn o t parllclrl per cubic loot o | Air Piper Hill Oruahlac labeatoe (ntQ lk>[) ............................. 1 liai;aine b e r lo i (Mill Alter) _ .... ....... ....... . 1 Karl **alf ( d f pipe lO K iu l .......... ......................... 1 >Uibi*lr I** Mtiwluf i M o a lumber 1 Hamllng i i b t t lo t lumber m 4 tilt (Iroavloi bathroom i l l * ....... .......................................... t Uuilittr til (A*l>t a p rir booUt) __---------------------- 1 M isurali lit WIKfll) FUllos bnela with m iiM a li _____ 1 Hltorellnf m asselli on pill .......... - ______ ________ IhtnipItM b irrtla fatto B u n _____________ ____ O i n l o f pipe m o k i* ______________________ ___-- Kreilioc fauulitloo loto trimmer ......--...................... tfMovloff buulatlo l i o n trimmer Cntiblug im i b ag g lat Mr 1 Clulcfa Vicfatp **ytlpt|lpr** ffttifi|l T__i r i j i u i r n i . i n - i i n i iii__in_g 1 arladlas iibeatoa piper clutch lieto( 1 ....... ........ ... HrllMn* piper dutch la c in ia .............. ....... ................... 1 U.P-III. IPM M.I IM. It.-.* tl.l-P t.t tl.l UM. .WM.A ra .t lii.v w .s i. M -ll.l tsl.o-fau.p IP tu.l-tlt.l It.l I ! I IS