Document ooXr0w9x2r3Rzn5DJ0j6dqvR

- Z8, JM. I Scant or iogs and s results indicate .tion of rabbits. ace and itt which the urbe tiller tor samples c indices id Mrs. riments. pigmen: 1 above. ^s 5- Arch. propanol snsration Arch. :ilc halo> 25: ii-ilogtca! J-, W: <n Cun* toa'dry rthyiene. . T. L., V. T.: ethylene md the jacoL FJtKtca, \ tetra'studiss. CJJi.-.'d. Ac . -jt ^ T>-'~^cV x. " ' . A HEALTH SURVEY OF PIPE COVERING OPERATIONS IN ;" ' CONSTRUCTING NAVAL VESSELS* ' Waltz* E. Fleischer,1 Frxde&ich: J. Vxles, Jr.,1 Robert L. Gadf* and Philip Drinzer4 AN INDUSTRIAL health inspection of an felt and pipe covering in naval work are' its low r\ important U. S. Navy Contract Yard thermal conductivity, light weight, strength, and indicated that dustiness from miscellaneous refractoriness. When the Felt and pipe covering pipe covering operations was considerable and that were first developed, we were still building vessels a leer of the employees had what appeared to be under the Washington Treaty of Limitations in. ubestosis. `jEhis is a well-known industrial disease Tonnage, and every pound saved .meant that much tavied by only one thinr-onalonged hreathingof more armor, guns or ammunition for a given asbestos dost. The clinical manifestations are displacement, to say nothing of more economic shortness of breath and an unusual chest picture operation for the weight involved in insulation. by X-ray. In industry the disease is often dis Amosite pipe covering weighs about 14 pounds abling, but it is much less frequent than silicosis, per cubic foot, with a temperature limit of 750F. with which it very properly is classed. as compared to magnesia with a weight of 16 It was not felt that experience in a single yard pounds per cubic foot, and a temperature limit of was enough to justify any general statements on 500 F- High temperature amosite pipe covering working conditions in other yards, and certainly weighs about 18 pounds per cubic foot aa compared was no cause, for alarm, but the results warranted to 26 pounds per cubic foot for other high temper diecfc-tips elsewhere. Accordingly, arrangements ature insulations. Because of the lower con were made to examine by chest X-ray the pipe ductivity and the higher temperature limit of coverers in two Government Navy Yards, A and the amosite type, less of it need be used in a com B, tod in two Navy Contract Yards, C and D. bination covering than other types of insulations. Ruminations were made of the working conditions The development oi amosite felt started in including dust counts of the air breathed with 1934 when a need existed to secure a thermal microscopic and chemical analysis of the dust insulation lighter in weight and thermally more itself. ' . efficient than the materials (blocks and cement or We would point out that this procedure is asbestos blankets) which were then being used customary in making such surveys of occupational on. destroyer turbines. The Navy approved the diseases--medical examination of the workers type developed by a manufacturer ia September, and a study of the nature and concentration of 1934. Originally amosite was used only for the contaminants in the air breathed, turbine insulation, but it proved so satisfactory Pipe Covering Material that its fieid of application enlarged to include insulation of valves, fittings, flanges, etc. From An important ingredient of pipe covering iBaterial used on U. S. Navy vessels is amosite. This mineral is a magnesium Iron silicate of variable composition. The name is the generic one for an asbestos type of fibrous mineral mined in South Africa. the initial destroyer, it has been used on almost ah the destroyers built since that time and on all other combat vessels built since before the War. Pipe covering was a later development in late 1935 and early 1936. Due to the manufacturing The duel reasons for the wide use of amosite Received for publication September 21, 1945. Puhiiheei by ptrxnuiioa of the U. 5. Navy. 'lie opin ion* tad Ufrerhoos contained herein arc the private one* jdtfae yriten, and are not to be construed as official or verting the views a the Navy Department or the fcavalservice at large. * Cadr. MC, USNR, Asst. Chief Health Consul rant Lcul H(S) USNH. Health Consultant. [La_ EfS) USNR, Health Consultant, 4.100O. uer Health Consultant, U. S. Maritime Coinmia- problems involved, it took a longer time to evolve into a satisfactory shape, and its first use on naval vessels was in 1937. Since that time its use.has spread markedly and it was used on the great majority of naval combat vessels built during World War U. . Water-repellent amosite felt was developed during the early part of 1942, as a replacement for hair felt in the insulation of cold water lines to prevent sweating. Hair felt had the disad- 9 10 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [wJ. 22, no. 1 vantage of being combustible andas it was organic, is marked into measured sections and cut with when, it became wet it moulded or rotted and a rotary electric hand saw. The cut sections are could harbor vermin. At this time fires on roiled up and either used immediately or stacked board certain naval vessels convinced the Navy in the storeroom. of the desirability of eliminating any combustible Usually one to three workers are employed at material from on board ship. Eventually water- this operation. During the handling, unwrapping repellent amosite was made in strips of 50 loot and unrolling of the asbestos, considerable dust lengths and of suitable width to enclose the arises, but appears to settle readily. A very fine circumference of the pipe and enclosed in an water spray should be used for wetting down the. extremely light-weight muslin to facilitate hand material as a high velocity spray stirs up dust. ling and reduce the dust, which the tvatcr-re- Once it is wetted the handling and cutting of the pelicnt agent accentuated. material causes little( visible dust. All of the I. Description op Operations and Working _ ENmONlCENT four yards surveyed wet down the insulating material described above. One NavyYard has an elaborate exhaust system 'Asbestosis results from breathing asbestos for the layout table. The entire top of this table fibers of relatively long length, such as 15 to 7S Is covered with small perforations through which microns. It is not caused by breathing chopped tilt air is exhausted. This table is sufficiently up asbestos fibers of one or two microns (1). large that no more -than two-thirds of the top is Therefore we are concerned with the presence in ever covered with material and room air is thereby air of asbestos fibers which can be seen as such exhausted through the other third. While no under low power of the ordinary microscope. velocity or capacity measurements were made The clinical picture of asbestosis can easily on this system, data presented later in the report be complicated by the presence of diatomaceous indicate that this control measure had a marked earth, a form of amorphous silica, which can effect in reducing the dust count. causa silicosis and is probably a more serious t2. Band saw cuilinz health risk, than asbestosis. ' A standard band saw such as is found in wood Another dust which may be present is magnesia, working shops is used to cut insulation blocks and MgO, which is in very common use as a heat boards into desired shapes. This operation insulator and is harmless. produces large amounts of air-bome dust, most Therefore our analyses were done to indicate of which settles slowly. Normally there is only how much fibrous type of asbestos dust was one worker on this operation at any one time. present in the air breathed, how much silica was inasmuch as this is a very dusty operation^ present (especially as diatomaceous earth), and tthe band saw should be enclosed in a room bv how much of the harmless ingredients like iron itself ami should be eg^inncfl with. ariMinw in^| oxide and carbonates. r.exhaust ventilation both above and below the Pipe covering may be divided into seven different saw table. Bemuse at the mechanical difficulties operations as follows: in locating this exhaust properly, some of the adust will escape into the air and the operator should 1. Laying out and culling ; -therefore wear an approved dust respirator, 2. Band sau> culling 3. Sewing and preparation of bools and jackets 3. Sewing and preparation of boots and jackcls In. this operation jacket covers for valves and 4. Cement mixing 3. Maiding pipe joints are fabricated. The work consists of 6. Grinding cutting asbestos doth with shears, padding the 7, Installation on board ship1 jackets with insulating material, and sewing with wire or asbestos cord. These operations give 1. Laying out and culling rise to only slight amounts of visible dust, and Rolls of the insulating islt are unwrapped and exhaust ventilation and respiratory protection unrolled on a large layout table or on the door are neither required nor used. There is usually of the shop. This material, with the exception a large number of workers doing this operation of the type- known, as water repellent amosite, is In one large room. then well wetted with a fine water spray. It 1-4. Cement mixing For proto fie insui&tie with cemen asbestos fib< of water is a thoroughly ; mull amour i pail with a when the as miring trouj mixing. Ord icparxte root The dustines of exhaust \ or both, aithr Petrograph dirate that I may be as big 5. Molding Molding- is tion to fit odd form is made insulated. 1 sections -*ued with ti ?s with asbestos iesalatkm can to be installed usually done operation. Ve operation and ; prelection is ri 5. Grinding Several ship) prefabricated s up this mater; cement, all ol dustiness. Nor quent intervals exposed, but t general room e: respirator worn 7- Insinuation There are a : pipe covering o wrapped and po aad joints and l or asbestos cord with prefabrica: some hand sew mixed cement is a smooth Sxds ' cut witia rctions are ir stacked , .ployed at wrapping a.ble dust . very fine down the up dust. lng of- the J1 of the insulating jst system this table ogh which ufBciently the top is is. thereby "While no ere made the report a marked j. mi wood cocks and operation, lust, most re is only time. operation, room by juate local below the dillicultics ne of the tor should. rrftor. ml jackets alves and insists : ddtng the wing with dons give dust, and protection is usually operation :-fbr protection and to give a neat appearance with glass doth or asbestos doth for greater tie insulation on board ship is usually covered strength, the only operations that produce much *Hh, cement containing a high percentage o dust are the wrar>r,m? and pounding of xmositc ibatos libers. In mixing, the proper amount =-*gd the sewing of sections,, jnter is added to the dry asbestos cement and ^Nearly all of the compartments on board ship thoroughly agitated with a hoc. Occasionally <uc involved in this work, although most of it is iraaQ- amounts of asbestos cement are mixed Jn iconceatrated in the machinery spaces. Usually a pah with a trowel. /Considerable dust is raised the greater number of pipe coverers work on board when the asbestos cement is dumped into the -ship and relatively few men. in the shop. The aiising trough and during Iht .eariv stages of 'spacing oi_ workers ranees from one or two men sailing. Ordinarily this process is done in a -doing a small job in a living space to as many, separate room and only one operator is exposed. -as twenty or thirty men, working on ten or more the dustiness of this operation warrants the use .jobs in the engine room. Temporary exhaust -of exhaust ventilation or respiratory protection ventilation is seldom used on board ship for pipe or both, although neither is generally tised.j covering and very few of the workers wear respir- Petrographic analyses of asbestos cement in ' atom. dicate that the amount of diatomacaous earth Seea.use of the varied nature of pipe covering may be as high as 87 per cent by count. generations in ship compartment*- f*rra1 grhanar 5. Molding amaxfla t inn is. fry hr preferred If the Compartment Molding is the process of building up the insula- _is large, such as the main engine room, five a[r lion to hi odd shapes of boiierworh and piping., A changes per hour are needed. In small com form is made to the exact shape of the part to be partments, such as living spaces, tea to fifteen innuiated Block insulation is laid on, adjoining air changes per hour are required. . sections glued together, exposed surfaces sealed with asbestos cement and the whole mold covered II. CojcposmoN or Mktsxiais Used with asbestos doth. When dry, the molded insulation can be lifted ofi the form and is ready to be uncalled on hoard ship. This operation is usually cone in the shop next to the sewing operation. Very little dust is produced from this operation and no special ventilation or respiratory jimiectiot! is required. 6. Grinding ' According Navy Specification the rovings of asbestos insulating felt (amositej shall contain not less than 95 per cent asbestos fiber of the following composition: Silica (SiO;) percent minimum........................... 47.S Iron oxide (Fe-Oj) per cent maximum................... 45.0 Magnesium oxidefMgOjperceniminimum...... 6.0 Several shipyards reclaim their scrap pieces of prefabricated sections of. insulation by grinding : up this material and using it in the asbestos rement, all of which contributes considerable dustiness. Normally this job is done at infre quent intervals and only one or two men are exposed, but the operation should be isolated, general room exhaust supplied and an approved Japirxtor worn by the operator. ^_lntlaUcSit>n of frifre canerint on board shit> _There are a number of operations involved in Pipe covering on board ship. Insulation felt is `wrapped and pounded tightly around large pipes tad joints and fastened firmly in place with wire Qr ttbeates cord. Pipes and boilers are covered with prefabricated sections, which necessitates some hand sewing to fit the sections. Ready Typical analysis of the two types of asbestos fibers in general use are tabulated below: Ckryutilt Amtti U Silica (SiOil .................... ... 39.05%........... 50.24% Magnesia (MgO)............. .. 40.07%___ .... 3.96% Alumina (AJ*0j).............. .. 3.67%....... Ferric oxide (FejQ})...... Ferrous oxide (FeQ)........ 2-41%....... .... ... ".80% 32.00% Sodium oxide (NatO)___ ... 2.12% Combined water (bljO)... .. 14.45%....... ... 3.00% Therefore amosite alone will not comply with Navy Specifications because of the low magnesia content and must be mixed with .chrysotile asbestos to equal or exceed the 6.0 per cent mini mum value for magnesia. On the other hand, chrysotile cannot be used alone because of its mu*d cement is applied to fill in spaces and give silica content which is below the minimum 47.5 4 smoother finish. Some insulation is wrapped per cent specified by the Navy. The two types 12 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [wL 28, bo, / of asbestos fibers must be mixed together hi the proper proportions to satisfy the values set for magnesia and silica. The amounts of these materials used to form this mixture therefore would be 6-43 per cent chrysotQe asbestos and 94-57 per cent amosite asbestos. These two fibers differ mainly in their physical characteristics. Chrysotile is capable of being readily separated into very fine, fibers with a soft silky feel, whereas amosite is harsher and requires more manipulation to fiberize it. One authority has stated that the chcysatiie has the finest in dividual fibers, and amosite the coarsest. Be sud sewing were done with a small amount of space for storage. Cross draft ventilation WM provided by open windows on both sides of the room. Work on board ship was not supplied with exhaust ventilation. No asbestos workers were found wearing res. pirators. 17. 5. Navy Yard B. There were 50 men working in. the shop and 7GQ men on board ship. The shop was divided in;tl four main rooms: Layout, Sewing, Cement, and Storage and Band saw combined. With the TABLE 1 Scmuav or Matesxals Used at Each. Yaks rxa Mokts K*vr YASO A KAVY YAfc * . nNTKACX CABS C Amosite 58,200 sq-ft. SO,000 sq.ft. 40,000 sq. ft Amosite (water-repellent) ' -- . 15,000 sq.ft. Prefabricated sections (molded and block) 600 sq. ft; 1,200 sq. ft. . 39,900 linesrft 113,000 linear ft. 1.750 sq.ft. 18,800 linear ft Asbestos cloth 76,500 sq.ft. 106,600 sq. ft. 34,700 sq.ft. Metallic Wriae Asbestos yarn -- 150 Ih. -- Asbestos paper -- 5,SCO sq. ft 4,000 sq. ft. Asbestos board Asbestos cement 2,700 linear ft. 34,400 lb. 6,000 sq. ft. 13,000 lb. 150 sq. ft 57,500 lb. COwraAer rxsjj o 6,325 sq. ft. 3,300 sq.1 ft 15,700 linear ft 40,000 sq. ft '-- 5,500 sq. ft. -- 38.500 lb. jm.1946. touring * rerphstoi priced un fabrics tk tarried o waidone Matcri room an< reipiratai through i a pari of There . other thi pipe covt ' walls tnc frequent . dcmcr. applied ii Ctmirac There working c were dom and jacks iabricated sr- si uk -utti twi fiie { is either 3 on boards in & comps who wore man who * no i>a fV. Anal1 cause of this difference we may suspect a decided decrease in the number of respirable fibers (below 200 microns in length and 5 microns in diameter) whenever amosite is. used in preference to chiysotile asbestos. .III. III. Pipe Covering Facilities at Individual Shipyards U.S. Navy YardA. There were 84 men working in the shop and 467 men on board ship. The shop was divided into two rooms, one of which was primarily for storage and occasional grinding and band saw cutting operations. The only mechanical exhaust ventilation in the shop was provided for tiro grind ing, mixing and band saw cutting operations and. was inadequate. In the other room layout, cutting exception of the Cement Room, the doors between these were normally left open. The work in the Sewing Room consisted mostly of fabricating and sewing valve boots and jackets. All the cement used on board ship was mixed in the Cement Room. There was no exhaust ven tilation for either the Sewing or Cement RoomThe band saw was equipped with a flexible exhaust tube above the table and.ta exhaust around the blade below the saw table. The layout tali*' wax equipped with exhaust ventilation as describe! above. There was no exhaust ventilation supplied on board ship for pipe rovering and no workers were found wearing respirators. Contract Yard C. There Were 51 men working in the shop and 121 on board ship. Layout, cutting and cemetf There at if safe (j l>teeu*a the ubest particles 0. to that ir that the a log industi In textile specific jot lor some ; rotate bet1, large ship In dust exp la coqq mvereris n ZS, no. / till amount of cntiktion- was th sides of the supplied with d wearing res- -e shop and 700 as divided into Cement, and <ed. With the Y.vm& s> 6.325 sq- ft. 3.300 sq. ft. 15 .linear ft. sq. fr*. 5.500 sq. ft. W.500 lb. it* doors between consisted mostly >cts and Jackets, .p was mixed in io exhaust venCeme.nt Roomflexible exhaust mst around the ie layout table .ion as described _|ila lion,supplied uid no workers if 3 and. 123 f cement were done at one end of the shop. Dust bestos content, ranging from 85 per cent magnesia respirators were occasionally worn during these (10-15% asbestos) to amosite (95% asbestos). procedures. At the other end of the shop the When asbestos cements contain large amounts fabrication of boots, Jackets and molds were of diatomaceous earth there is a resultant silicosis anted out. A small amount of such fabrication hazard as Indicated above. , was done on board ship. ' . fa general we 'feel that dust founts below g Material was cut with a band saw in a separate fertllidn particles per cubic foot bv Kanimeter toom and the operator wore an approved dust ^indicate good dust controj. respirator. The dust from this saw was exhausted Our figures in Table 2 were determined by the through a slot under the table which caught only Konimeter and not .with the impinger instrument. a part of the dust given off above the table. We used the Konimeter because it is light, easily There was no exhaust ventilation in the shop, portable and takes records which can be kept other than lor the band saw, and none for the indefinitely. tAs Is indicated in Table 3. the pipe covering operations on board ship: All floors, fustiest operations are band saw cutting, cement walls and rafters of the shop were cleaned at .-rraxmg, and installation on board ship. ' frequent intervals with an industrial vacuum denser. Most pipe covering on board ship was .. V. Medical 'Findings' applied in the evening during the second shift. Contract YardD. There were 8 men in the shop and 160 men working on board ship. Pipe covering operations were dote in. two shops. In the roam one, boots and Jackets for pipe valves and connections were fabricated and surplus material stored. In. the gsailar shop the operations consisted of layout aad cutting of amosite, water repellent amosite and Are felt. There was no exhaust ventilation in either shop nor for the pipe covering operation on board ship. All the asbestos cement was mixed The incidence of asbestosis among pipe coverers as determined by chest X-ray is given in Table 4. The relation between years of exposure and per cent asbestosis is included in Table 5. Due to frequent turnover of shipyard workers and the length of time required to X-ray a large number of workers, the number X-rayed may not equal the number of pipe coverers. At Contract Yard C X-rays were examined of men who bad left the yard while at Navy Yard B & few pipe coverers were not X-rayed, At Navy Yard A the 48_ X-rayed out of 551 were all older men working in a compartment on board ship. The only worker who wore an approved dust respirator was the mm who cut the two types of amosite. There was oc hand saw cutting of asbestos in this yard. in the shop. Some of these pipe coverers had had pre-shipyard experience in the asbestos industry, but the tables are based solely on shipyard exposure. At IV. Analyses op Settle Dust ant Dust Counts Contract Yard C, for example, the Asbestos Shop estimated that about one-third of their pipe coverers had worked with asbestos before coming There are no established figures for permissible to the yard. or safe dustiness in pipe covering operations. The one case of advanced asbestosis at Contract Hhtcisen et ah (2) in their study of asbestosis in Yard C had worked in the asbestos industry far the asbestos textile Industry suggested:^ million C=23 years before coming to work in the yard. At particles of totaL dust by impinger as a threshold Contract Yard D the two cases of moderate ioc that industry. We should like to point out asbestosis had worked 22 years and 30 years at that the asbestos textile and asbestos pipe cover* pipe covering in their yard. sag industries differ widely in their dost exposures, Ail of the X-ray films used in the above data la tt2e plants workers usually continue at were first read by roentgenologists of the Medical Hwddc Jobs with fairly constant dust exposures for some years, whereas the pipe coverer .may 'otfcte between shop and ship and from small to ship compartments with a wide variation dust exposure. Ia contrast to the textile worker, the pipe covereds materials differ markedly In their as Department of the yard and then by one of the -authors (-1V. . FJ-.- Dr;- -Wv Cv Dreessen, V. S. P. H. $., was kind enough to examine the three positive plates and he agreed on the diagnosis. Since only three workers out of the 1074 X-raved had asbestosis, and each, of the three had been a pioc coverer for more than 20 years, it would f /I rsfiii - TABLE 2 Anamsss or Scrcum Dust juno Ara Sakpizs OKKATiQX - S not CXMT ZJCU T*AX 10 KZCXOXX IV COOKT s*ats* aH-XCs *8 rmas r! mc u2m * fiS Jmi < 53 tn 1* tm ^ ,! o- w 8 3 Is 11 5 JsSfc o Is a* u sore comm* flfiWCf)* Taul (hue ACKSTCt oust &SSR Of OMUU Aver *** JUiifetjf [Aver ceunts nXCEKT A(nr*xen*eo)s Layout and cutting . Xavy Yard A............ .......... 95 16 6 12 6 Xavy Yard E..................... 93 10 S 12 tr Contract Yard C....... ......... 30 5 10 tr Contract Yard D................ So 26 6 8 tr 24 26 40 IS 26 14 29 21 10 2 12 7 15 4 10 1 5 3.5- 8.7 6.1 0.21-0.50 O.JS5.7- 6.Q 1.6- 6.5 4.2 0.01-0.54 0.230.6- 7.9 17.1-- 25.2 20.5 1.13-4.30 2.18 6.6-19.5 6.5- 16.5 10.9 0,09-1.16 0.63 1.4- 8.7 Cutting with band saw Xavy Yard A............. Navy Yard B..................... 98 . Contract Yard C. ........ - 98 9 7 8 tr 9 63 2 tr 2 U.0- 19.2 15.1 0.10-0,14 0.12 0.7- 0.9 48 16 12 2 32.4- 46.6 39.S 2.8-' 3.2 3.0 6.-S- 8.7 10 4 12 3 18.2-100+ 73+ .*-12`.S 6.19 4.3-12.8 Molding operations Contract Yard C................ 98 Contract Yard D................ 95 8 66 3 tr 7 6 10 4 9 7 tr 48 10 12 Sewing Sc prep, of boots & jackets Xavy Yard A.. Navy Yard B (Sewing as- bestos cloth) 98. (Stuffing with amosite).... 98 Contract Yard C................ 95 S3 ` 12 , er 9 tr 8 8 U tr 26 6 n 3 6 6 a tr 2 3.5- 6.1 4.6 .01- .06 0.03 0.3 -1.0 42 21 16 3 3.3- 6.0 6.8 Q.Q- 9.4 0.1 0. -6.4 38 20 15 1 2.X- 2.1 0. 0.3 0. 28 12 14 2 10.6- 12.3 11.4 .45- .79 .62 3;7 -7.4 38 28 14 5 3.9- 10.9 6.0 0. - .05 .03 0. -0.5 Storeroom Contract Yard D................ 93 Cement mixing 15 8 t i 7 tr 26 32 12 Contract Yard C................ Contract Yard D (on board ship)-.'............................ l./ 2 33,8- 48,7:41,3 i.6 -4.7 3.1 4.7-10.0 5 19.6- 40.032 0. - .02 .01 0. - .001 Grinding scrap materials 88 8 20 16 1 10 33 12 15 9.4-100+ 50+ 0. -1.6 .47 0., -2.6 General room. Navy Yard A............................. Navy Yard B............................. Contract Yard C..................... Contract Yard D..................... 49 0.2- 24.6 10.0 Or- -1.4 0.08 .02-0-3 2 1.6- 3.3 2.4 0. - .01 .01 0. -0.6 4 0.0- 21.6 14.2 0.34-1.7 .8 3.8 -7.9 5 3.9- 10.9 6.0 Q. - .05 .02 0. -0.5 Aboard ship Navy Yard A,............... ........... Navy YardB............................ Contract Yard C................... Contract Yard D..................... 30 65. -25Q. 142 0. -0.17 0.02 0. -0.Q5 15 84.4-192.0 128 1.36-5.21 2.8 1.1 -3.7 15 25.3- 89.0 49.2 0.23-2.38 1.10 0.S -6.8 15 8.0- 22.1 11.0 Q. -0.21 0.03 O. -1.0 1 Note; MPPCF -- Million particles ol dust per cubic foot of air. * 14 -fm*x *r }rK.* f' kyoatand p. Bsnd saw cull Sewing ind (a Cement mixin Orindi&g....... Qeaenl room. Shop avera* Ship *verag> KoU: MS IjJCIDEfCE 0 Kwyr riA. Ntj\ .B. Csatzact Yard CiMtnct Yard Totals........ j!ZU.TU>.\\S!U!' N'vy Yard A Navy Yard B Cootract Yard Contract Yard  \ Tam. 1946] PIPE COVERING OPERATIONS IS m aarr amesto* (nwfe) * - s < 5.7- 6.0 i.0.6- 7.9 'S|16.6-i9,5 5 4- S.7 | 2:0 .7- 0.9 'f, =U.9 7 /4.3-12;S TABLE 3 CQHPAJtcsQN or Dustiness or Vasious Opezations m Each Ssh-yazd orzK4.Tta.ir KAVY YAED A. mavt tjuu> a oeoraust YAa c CBIRUCT J Touf duit j Asbeitet 4tut Totil diut Aitlot dull Total dot AibalOe dust Total da Aibaiaa dual Layout and cutting........................... Band saw cutting........................... . Sewing and fabrication.................... Cement mixing................................... . Grinding................................................ General room....................................... UPPC?' 6.1 15.1.- 4.3 31.0 50.0 10.0 0:35 0.12 0.03 0.2 0.47 0.08 MfPCT 4.2 39.5 4.3 S4.0 0.23 3.0 0.1 1.7 2.4 0.01 UPKP 20.5 73.0 II.4 41.3 : 2.18 6.19 0.62 5.1 14.2 0.8 XPPCF 10.9 0.63 6.0 32.0 0.03 0.01 6.0 0.02 Shop average....................... Ship average.................................... 30.0 142.0 0.25 0.02 26.9 12S.Q -- l--P 1.0 2.8 ' Note: MPPCF <-> Million particles of dust per cubic foot of air. 32.0 2.6 7.6 1.1 j 11.0, 0.23 0.03 TABLE 4 appear that asbestos pipe covering nf naval e IJODZNCE OP ASBESTOSIS ASfO.VC PIPE COVZSXRS a 'relatively safe occupation. However, it must 0.3 -l.Q --*> \ -6.4 -- -7A llO. --0.5 nZTTAiD xmtar* or a*x 1 miuacz or casks or Asazsxosis m KAVXfi Mini- Mod Ad ffl* \ erate vanced be remembered that these men rotated among the various operations of pipe covering aad;were not continually exposed' to high concentrations of asbestos dust as found in band saw cutting and cement mixing, vThc suggestions t*-||fivy Navy Yard A............. 0 0 0 g.m exhaust venti2ation,andjesoiratorv,nrotectip_a Navy Yard B......... 750 Contract Yard C.... 174 Contract Yard D... 165 662 196 0 0 00 0 lip i are therefore of value m. mauttaw"g this low /incidence of asbestosis^ 0m 0 pbuk................. 1683 1074 0 2 1 Discussion . The extremely low incidence of asbestosis found, 0.29 per cent, or 3 cases out of 1074 pipe TABLE 5 aivcrers, stands in marked contrast to the high 0. - 0.7 5.4- 2.5 '4.7-10.0 i'O. - .001 itEU.nu.'csmr Between Length <h` Exposure axu I.VCtDSCXCE OF ASBESTOSIS sairvAStf vc.\ts Fim rovriivc INSWHY 0-2 -s s-to , 10 plm dust concentration found in several of the pipe covering operations. As shown in Table 3, the total dust concentration for band saw cutting ranged from T3.1 to 73,0 million particles per cubic feet, for cement mixing from 31.0 to 84.0, and for installation on board ship, from 21.0 to 142.0. -"0. -2.6 ** -02-0.5 10. -0.6 ;3.s -r.9 ';o. -0.5 [Exposed............ ^Percentage.. .. 26 0 0% 13 8 \* 0 0 -0 Q% 0%io% Navy Yard B Exoosed............ 225 435 67 '22 Affected............ 0 000 Percentage. .. . 0% 0% 0%i 0% The solution of this apparent discrepancy lies in a characteristic peculiar to the pipe covering trade, that Is lack of a necessity for specialization. In general, pipe coverers are capable of doing all of the operations described above, and the worker may be changed from one operation to another or to different jobs in the same type of operation without loss of efficiency and according to the -2|O.---0rG5jl.l -3.7 [Exposed___ Retract .Yard-C- (Affected.-.,-. Percentage.. 0 105 43 17 0... -0~ 0 - .j... 0% 0% 0% 6% demands of ship construction. It is therefore apparent- that a pipe coverer's environment may change every few days or few weeks at the most JJ0.5 -6.3 5,0. -1.0 Contract Yard D * Exposed... 26 118 5 9 Affected.... 0 0 0 2. Percentage. 0% 0%; Q% % with a constant fluctuation in the dust concentra tion which he breathes. Therefore, the figures given in Table 3 for shop average and ship average cannot give a composite picture of the asbestos ji i! i r 16 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY jaol. 28, no. I dust that a worker may breathe over a period of ^among these workers would have been considerably years. It is further apparent that to obtain such greater. In view of the varied character-of the a picture, daily dust taunts at each specific job '.environmental dust exposure in the pipe covering in each, ship compartment and in the shop together industry on naval vessels, it is manifestly impossible with the time spent on each job would have to Ko set a threshold. . be compiled separately for each worker. In this respect, asbestos pipe covering differs markedly VI. CoNCxrstoss from the asbestos textile industry where dust 1. The character of asbestos pipe covering concentrations far an operation `do not fluctuate . Industry on board naval vessels Is such that widely and where a worker will usually remain at conclusions drawn from other asbestos industries a specific job for some years. such as textilesffannot be applied. . A further factor in maintaining a low incidence 2. The operations of band saw cutting, grinding, of asbestosis is that in band saw cutting, grinding, cement mixing, and installation on board ship and cement mixing only one or two men are in should be equipped with exhaust ventilation to volved and the work is usually done at infrequent keep the total dust concentration low. intervals such as several times a week. 3. The incidence of asbestosis''among pipe Finally, pipe eoverers also apply glass wool, eoverers In the shipyards'studied was low, 0.29 per rock wool, magnesia, and other types of non cent or ! cases out of' 1074." In view of the nature asbestos insulation, all of which decreases the of shipyard pipe covering work, this low incidence amount of exposure to asbestos dust. t seems is not surprising. f. likely to us that if the pipe eoverers studied had 4. Since each 'of the 2 cases of asbestosis had esvorked steadily at any of the above operations worked at asbestos pipe covering in shipyards for rwhere the amount of asbestos dust in the air was more thanfZQ years, it may be.concluded that such i consistently high, the Incidence of asbestosis pipe covering is not a dangerous occupation. _ REFERENCES .' . ^X\\ LaKZa, A. J.i Silicosis and asbestosis. Oxford *^(3) Fahey. J. C.: Ships and. aircraft of the United University Press, New York,, New York,. J93S. States Fleet. 2nd War Edidoo, 944. Pub 0-T2) Dkeessew, W. G et al.: A study of asbestosis lished by Ships and Aircraft, 1265 Broadway, in the asbestos textile industry. Bull. No. New York, New York. 241, Public Health Service, U. S. Treasury Department, 1938. , %* *.a J ; `ESK plates upon prevalent o; surfaces ix measures ini application a dame, to a di or acceimpan fjftyri'nViT.g menis or con the operatic measures are recently prov shrinkrr dev of nitrogen pc 10 da; *er Three -.er exposure expe: lymptoms, bi following day. The purpose the ex|ur vnall, unvent!. `iTie torch < the mnvcntic in most instai annular ring which supplies *it water arouc Urion of the tc 'feel plate can As with axyze of the torcl of metal eaaxj ducted on thin: wage cemojooJ apadry of the * Received ( 1 Industrial H;