Document rpR6YZeOo2oVR3m0EejJnEz30

lM vjc.de . r r\jJk. sA. hrt Ces^ r\ V G-*-\.c_tJkc VA4.h_; i-- aJv logs and s results indicate .tion o( rah bits' lice anti le which the urine tiller torsamples c indices id Mrs. ` riments. pigment 1 above. ' 4b i. Audi. persaturpropanoi 'iteration Arch. :ile haJo' J:, 25: sinlogical IX: a Ctjxtoxid cy ithylene. . T. L., V. T.: ethylene ind the iacoL. & FEKm, 1 terra 's Ludies. ' . A HEALTH SURVEY OF PIPE COVERING OPERATIONS IN " CONSTRUCTING NAVAL VESSELS* 1 Walter E. Fleischer,1 Frederick J. Viles, Jit./ Robert L. Gade* and Philip Drinker4 AN INDUSTRIAL health inspection o an felt and pipe covering in naval work are its low important TJ. S. Navy Contract Yard thermal conductivity, light weight, strength, acd 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 few of the employees had what appeared to be under the Washington Treaty of Limitations in asbestosis. `This is a well-known industrial disease Tonnage, and every pound saved meant that much iaused fay only one thing--prolonged breathing of more armor, guns or ammunition for a given asbestos dust The clinical manifestations axe 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 7SOT. 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 -wonting conditions in other yards, and certainly weighs about 18 pounds per cubic foot as compared war no cause, for alarm, but the results warranted to 26 pounds per cubic foot for other high temper ehedc-ups 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, tad in two Navy Contract Yards, C and D. bination covering than other types of insulations. Examinations were made of the working conditions The development of amosite felt started in including dust counts of the air breathed with 1934 when a need existed to secure a thermal microscDpic 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 in September, and a study of the nature and concentration of 1934. Originally amosite was used only for the contaminants Lu the air breathed. turbine insulation, but it proved so satisfactory Pipe Covering Material that its field of application enlarged to include insulation of valves, fittings, flanges, etc. From An important ingredient of pipe covering material 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 all 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 chief reasons for the wide use of amosite * Received fox publication September 21, 1945. nibluheti by pennmioc of Lhe U. S. Navy. The opinloct tad aaaertioos contained herein ate the private ones dttt-.nltn, and are not to be construed as official or rejecting the views of the Navy Department or the ^aval service at large. * Coodr, MC, TISNR., Asst. Chief Health Consultant ' Lieut. H(S> DSNR, Health Consultant. HCS) CSNR, Health Consultant. * Chier Health Consultant, U. S. Maritime Commis sion. 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 II. . 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 25110510 <r,V :^e rm'^, ' - im Vi. 1 -j* i i 3. i <1 i *.; 10 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY ttel. 2S, no. I vantage of being combustible and as 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 rolled 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 foot 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 water-re Once it is wetted the handling and cutting of the pellent agent accentuated. material causes little visible dust. All of the I. Description op Operations and Working Enyironieent 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 75 is covered with small perforations through which microns. It is not caused by breathing chopped the air is exhausted. This table is sufficiently up asbestos fibers of one or two microns (1). . large chat no more -than two-thirds of the top is Therefore we are concerned with the presence in over 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. cause silicosis and is probably a more serious fy. Band saw esdlinz 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-borne dust, most Therefore our analyses were done to indicate of which settles slowly. Normally there is only how much fibrous tjrpc 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 hv how much of the harmless ingredients like iron, itself and should be cfluinned.until ariemiarrt In^j oxide and carbonates. r.exhaust ventilation both above and below thq Pipe covering may be divided into seven different saw table. Because of the mechanical difficulties operations as follows: in locating this exhaust properly, some of the idust will escape into the air and the operator should /. Laying end and cutting ; -therefore wear an approved dust respirator, Z. Band saw cutting 3. Sewing and preparation of bools and jackets 3. Sciaing atui preparation of bools and jackets 4. Cement mixing In this operation jacket covers for valves and 5. Maiding pipe joints are fabricated. The work consists of 6. Grinding cutting asbestos cloth with shears, padding the 7. Installation on board ship jackets with insulating material, and sewing with wire or asbestos cord. These operations give 1. Laying out and cutting rise to only slight amounts of visible dust, and Rolls of the Insulating felt are unwrapped and exhaust ventilation and respiratory protection unrolled on a large layout table or on the floor 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, li 1-4. Cement mixing Jmc. JMd] For pxot {he insulatic with cemen sbestoi fit* of water is a thoroughly i small amoun a pail with a when the a< miring trou* mixing. Ord separate root The dustines of exhaust \ or both, althc Petiograpb diate that 1 may be as hig 5. Molding Molding- is tkm. to fit odd form is made insulated. 1 sections -lued with a;. is with asbestos insulation, can to be installed usually done operation. Ve operation and ; protection isn 6. Grinding Several ship) prefabricated s up this mater; cement, all ol dustiness. Nor quent intervals exposed, but L general room e; respirator worn 7. Installation There are a i pipe covering o wrapped and po od joints and f asbestos cord with prefabricai some hand sew: rotxed cement is a smooth Snis 1 ..d1, nO. / cut. with rctions are jr stacked .ployed at wrapping rable dust . very fine down the up dust, ing of the J1 of the insulating ist system this tabic jgh which ufEciently the top is is thereby While no ere made the report a marked i -u. wood blocks and operation iust, most re is only time. operation, room by iuatc local below the dilacuities ne of the tor should. nftor. nd jackets aives and mnsists of ddtng the wing with tions give dust, and protection is usually operation JmM .far protection and to give a neat appearance with glass doth or asbestos cloth tor greater the Insulation on board ship is usually covered strength. Hie only operations that produce much *fth cement containing a high percentage of dust are the wrannmg- and pounding of amosite tbatos fibers. In mixing, the proper amount ^aod_thc sewing of sections., jreter is added to the dry asbestos cement and ^Nearly all of the compartments on hoard ship thoroughly agitated with a hoe. Occasionally are involved in this work, although most of it is ffPn amounts of asbestos cement are mixed in ^concentrated in the machinery spaces. Usually a pall 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 airing trough and during the early stares of 'spacing of workers ranees from one or two men filing. Ordinarily this process is done in a jrioing a small job in a living space to as many eparte room and only one operator is exposed. j-MS twenty or thirty men working on ten or more the dustiness of this operation warrants the use .jobs in the engine room. Temporary exhaust grhimt ventilation or respiratory protection ventilation is seldom used on board ship for pipe or both, although neither is generally used^ covering and very few of the workers wear respir- Petrographic analyses of asbestos cement in ' atom. dicate that the amount of diatomaceous earth Because of the varied nature of pipe covering may be as high as 87 per Cent by count. operations in ship compartment^ r*nra1 5. ifolding awnrilatirm ig tn >w preferred^ If the compartment Molding is the process of building up the insula is large, such as the main engine room, five a^r tion to fit odd shapes of boiierwork 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, ten. to fifteen insulated. Block insulation is laid on, adjoining air changes per hour are required. '. colons glued together, exposed surfaces sealed with asbestos cement and the whole mold covered H. Composition op Materials Used with asbestos doth. When dry, the molded According to Navy Specification the rovings insulation can be lifted off the form and is ready of asbestos insulating felt (amosite) shall contain to be installed on board ship. This operation is not less than 95 per cent asbestos fiber of the usually done In the shop next to the sewing following composition: operation. Very little dust is produced from this operation and no special ventilation or respiratory protection is required. 6. ' Silica (SiO;) per cent minimum........ . 47.5 Iron oxide (Fe*Oj) per cent maximum................... 45.0 Magnesium oxide (MgO) per cent minimum......... 6.0 f>cveral shipyards reclaim their scrap pieces of prefabricated sections of insulation by grinding ; up this material and using it in the asbestos cement, all of which contributes considerable duitincss. 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 lapirator worn by the operator t?.. IruLclLqiyqn of tjpc covtrin^ on board There are a number of operations involved in pipe covering on board ship. Insulation felt is wrapped and pounded tightly around large pipes and joints and fastened firmly in place with wire Typical analysis of the two types of asbestos fibers in general use are tabulated below: Ctryitlilt Ai*li U Silica (SiOi).......................... 39.05%.............. 50.24% Magnesia (MgO).................... 40.07%................ 3.96% Alumina (AljOj)................. 3.67%..,..................... Ferric oxide (FcjOj)........... 1 . ^.............. 7.80% Ferrous oxide (FeO)...........j /a.............. 32.00% Sodium oxide (Na,0)..................................... 2.12% Combined water (NjO)........ 14.48%................ 3.00% Therefore amosite alone will not comply with Navy Specifications because of the low magnesia content and must be mixed with chrysotile or asbestos cord. Pipes and boilers are covered with prefabricated sections, which necessitates some hand sewing to fit the sections. Ready 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 mued cement is applied to fill in spaces and give silica content which is below the minimum 47.5 a smoother finish. Some insulation is wrapped per cent specified by the Navy. The two types :i -f ,12 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [f. 2S no, i of Asbestos fibers must be mixed together in 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 chrysotiie asbestos and 94-57 per cent amosite asbestos. These two fibers differ mainly in their physical characteristics. Chrysotiie 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 chrysotiie has the finest in dividual fibers, and amosite the coarsest. Be and sewing were done with a small amount of apace for storage. Cross draft ventilation w&s 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. U. S. Wary Yard B. There were 50. men working in. the shop and 700 men on board ship. The shop was divided in:u four main rooms: Layout, Sewing, Cement, and Storage and Band saw combined. With the TABLE 1 StrsotARY or Materials Used at Each Yard per Month HAVY YABP A KAVY AM> B nNTXACtrAXBc Amosite 53,200 sq..ft. 50,000 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 linear ft. 115,000 linear ft 1.7S0 sq.ft 18,800 linear ft Asbestos doth 76,500 sq.ft. 106,600 sq. ft 34,700 sq.ft Metallic twine Asbestos yarn -- 150 lb. -- Asbestos paper -- 5,500 sq. ft 4,000 sq.ft Asbestos board 2,700 linear ft. 6,000 sq. ft. 150 sq. ft Asbestos cement 34,400 lb. 15,000 lb. 57.500 lb. cornier tabu d 6,325 sq. ft 3,300 sq. ft. 15,700 linear ft 40,000 sq. ft. 5,500 sq. ft. -- 38;500 lb. 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 chrysotiie asbestos. . III. Pipe Covering Facilities at Individual Shipyards IT.S.NmyYardA. 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 the grind ing, mixing and band saw cutting operations and. was inadequate. In the other room layout, cutting exception of the Cement Room, the doors betwevn 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 . an exhaust around the blade below the saw table. The layout tahir was equipped with exhaust ventilation as described above. There was no exhaust ventilation supplied on board ship for pipe covering and no workers were found wearing respirators. Contract Yard C. There were 51 men working in the shop and 123 on board ship. Layout, cutting and cement 1944. fwt-Ang w fapimtoi procedure fabric* tk carried o wai done Mitcri room ani respimtoi through i a part of There 1 other tha pipe oove walls anc frequent doner, applied ii Contrac There working c were don< and jacke fabricated *rV si -atti and fire f in either 2 on board a in a comps who wore man who w no lia IV. Anal' There ai if safe <j Dreeiaes e the ubest ]jartides 0; f"r that ir that the * log industi In textile pecific jot lor some ; route bet* large ship In dust exp In coca eoverer's a [Kk'. ZS, no. I uJI amount of eotiktion- was th sides of the supplied with d wearing res- e shop and 700 as divided into Cement, and ed. With the :o.fr*ACT v.ixd d 6.325 sq.ft. 3.300 sq. ft. 1? linear ft. 1 iq. ft. 5.500 sq. ft. W.500 lb. it* doors between ronsisted mostly >ots and jackets, .p was mixed in to exhaust venCement Room- flexible exhaust lust around the ;e layout table .ion. as described _.tila tion. supplied md no workers n and 123 cement IrnLim. 'pTrlng 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 imbrication of boots, jackets and molds were of diaiomaceous earth there is a resultant silicosis ruried out. A small amount of such fabrication haxard as indicated above. , was done on board ship. ' . .. fa general we feel that Hunt counts below 5 Material was cut with a band saw in a separate taillidn particles per cubic foot bv Konimeter room 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 for the band saw, and none for the indefinitely, iAs is indicated in Table 3. tfre pipe covering operations on board ship; All floors, dustiest operations are band saw cutting, cement walls and rafters of the shop were cleaned at .-mixing, and installation, on board ship. * frequent intervals with an industrial vacuum doner. Most pipe covering on board ship was V. Medical 'Findings ' applied in the evening during the second shift. The incidence of asbestosis among pipe coverers Contract YardD. as determined by chest X-ray is given in Table There were 8 men in the shop and 160 men 4. The relation between years of exposure and working on board ship. Pipe covering operations per cent asbestosis is included in Table 5. were done in. two shops. In the main one, boots Due to frequent turnover of shipyard workers aad jackets for pipe valves and connections were and the length of time required to X-ray a large fabricated and surplus material stored. In the sculler shop the operations consisted of layout aad cutting of amosite, water repellent amosite 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 had left aad flic felt. There was no exhaust ventilation the yard while at Navy Yard B a few pipe coverers in either shop nor for the pipe .covering operation were not X-rayed. At Navy Yard A the 4S_ on board ship. All the asbestos cement was mixed X-raycd out of 551 were all older men working^ in i. compartment on board ship. The only worker in. the shop. who wore an approved dust respirator was the Some of these pipe coverers had had pre-shipyard man who cut the two types or amosite. There experience in the asbestos industry, but che tables was no band saw cutting of asbestos in this yard. are based solely on shipyard exposure. At IV. Analyses op Settled Dust and 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 Dtw&sen et al. (2) in their study of asbestosis in Yard C had worked in the asbestos Industry far the asbestos textile industry suggested';:5 million 423 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 lor 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. "^industries differ widely in their dust exposures. All of the X-ray films used in the above data textile plants workers usually continue at were first read by roentgenologists of the Medical Pecidc jobs with fairly constant dust exposures Department of the yard and then by one of the ft* lome years, whereas the pipe coverer .may authors (-W. E. F.)-.--Dr. W. C. Dreessen, U. Si t^ate' between shop and snip aad from small to P. H. $,, was kind enough to examine the three luge ship compartments with a wide variation positive plates and he agreed on the diagnosis. k dust exposure. Since only three workers out of the 1074 X-raved In contrast to the textile worker, the pipe had asbestosis, and each of the three had been. coverer's materials differ markedly in their as a dioc coverer for more than 20 years, it would iI Ii - TABLE 2 Analyses or Settled Dost xkd Aie Sakples OPHATIOH Layout and cutting . 'Navy Yard A....................... Navy Yard B..................... Contract Yard C........;... . Contract Yard D................. o II P8i na CENT XJCH TLUt to matom by comer Wu M*s *>* So SB ma * 3M-.0m 3 n5 2* Mm SW 1 u u N te.. < 5* W 3* ma s* 8 u Jq S om S b Ma 15 -S* .4. o i 95 16 6 12 6 24 26 10 2 98 10 8 12 tr 40 IS 12 7 05 30 5 10 tr 26 14 15 4 95 26 6 8 tr 29 21 10 5 sear cotWM jPPCF7s Taul dwe JUuie of Avercou&U Aauni sen Jwacewr ASBESTOS su&rc oi Aver* {nn*e) count* IX* ' - 3.5- 8.7 6.1 0.2M3.50 0.35 5.7- 6.0 1.6- 6.5 4.2 0.01-0.54 0.23 0.6- 7.9 17.1-- 25.2 20.5 1.13-4.30 2.IS 6.6-19,5 6.5- 16.5 10.9 0.09-1.16 0.63 1.4- 8.7 |^ I .yV: f:y *, " xt vfc'> '*? ' ,, 99 byoat and psaw cut'. Sewing and fa Cement mixin thindiAg......... Geaenl room. Cutting with band saw Navy Yard A.,........, Contract Yard C.......... 98 98 9 7 8 tr 9 63 2 tr 2 11.0- 19.2 15.1 Q.iO-O.14 0.12 0.7- 0.9 48 16 12 2 32.4- 46.6 39.5 Z.&- 3.2 3.0 fl.t- R 7 10 4 12 3 18.2-100+ 73+ .9-12.8 6.19 4.3-12.8 Shop averag Ship averag' 9HoU: MI Molding operations Contract Yard C................. 98 95 8 66 3 tr 7 6 10 4 9 7 tr 48 10 12 ' Incidence o Sewing & prep, of boots Sc jackets Navy Yard A......... ............. Navy Yard B (Sewing as bestos cloth) 98. (Stuffing with amosite).. .. 98 Contract Yard C................. 95 Contract Yard D................. 98 12 , tr 9 tr 8 8 11 tr 26 6 11 3 6 6 8 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 0.0- 9.4 0.1 - "tf-4 38 20 15 1 2.1 2.1 0. 0.3 * 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 n -n ^ Storeroom Contract YardD................. 95 Cement mixing Navy Yard A............... . Contract Yard C................. Contract Yard D (on board ship).................................. 15 8 7 tr I- i 1` 1' 26 32 12 i 16 3.4-- 30+'3l + 0- -0,52 0.2 0. - 0.7 2 A7 -.inrw-'Raj- 1.6 -1.7 1.7 I1 J_ 9^ % 2 33,8- 48.7 41.3 1.6 -4.7 3,1 4.7-10.0 5 19.6- 40,0 32 0. - .02 .01 o. - .ooi mrriU Vtry" A A. Naryv .B. Contact Yard Contract Yard ,, Totals..... J!iu.ric>xsnn' , .. - 1 s" Grinding scrap materials Navy Yard A....................... 88 General room Navy Yard A....................... Navy Yard B....................... Contract Yard C................. 8 20 16 1 10 33 12 15 9.4-100+ 50+ 0. -1.6 .47 * ~2 S 49 0.2- 24.6 10.0 0; -1.4 O.OB .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 0. - .05 .02 n Ji.f Navy Yard A Nsvy Yard B ,, Aboard ship Navy Yard A....................... Contract Yard C................. Contract Yard D................. 30 65. -Z5Q. 142 0. -0.1.7 0.02 0. -0.05 15 84.4-192.0 128 1.36-5.21 2.8 ti-^7 15 25.3- 89.0 49.2 0.23-2.38 1.10 0.5 -6.8 15 8,0- 22.1 11.0 0. -0.21 O.W 0. -1.0 * Note: MPPCF Million particles of dust per cubic foot of air. 14 Contact Yard - Contract Yard Jo*. 1944] PIPE COVERING OPERATIONS 15 m oarr asbestos (cuce) - ' 5.7- 6.0 ) 0.6- 7.9 * 6.6-19.5 3 1.4- 8-7 TABLE 3 Comparison or Dustiness or Various Operations in Eaot Shipyard omAxrov JLA.YT YAID A scayt TAxa a coimucr taju> c cqwtxact tazd a Total dust Asbestos dust Total dust Asbestoi dust Total doit Atbalu dust Total dut Asbestos dim layout and cutting.................... .. Band saw cutting.......................... Sewing and fabrication................ Cement mixing.............................. . Grinding........................................ General room................................. 6.1 15.1. 4.8 31.0 50.0 10.0 0:35 0.12 0.03 0.2 0.47 Q.08 MfPC? 4.2 39.5 4.8 84.0 0.23 3.0 0.1 1.7 2.4 0.01 jtrper 20.5 73.0 2.18 6.19 n.4 41.3 0.62 3.1 14.2 0.8 JtTKF 10.9 0.63 6.0 32.0 0.03 0.01 6.0 0.02 V 0.7- 0.9 6.S- 8.7 >:4.3-12:'S Shop average...................:------ 30.0 Ship average.............................. 142.0 0.25 0.02 26.9 128.0 1.0 2.8 * ifote: MPPCF Million particles of dust per cubic foot of air. 32.0 124 2.6 1.1 7.6 11.0, 0.23 0.03 i i' TABLE 4 appear that asbestos pipe covering of naval vessels ' Incidence op Asbestosis Amonc Pite Covxrers is a .relatively safe occupation. However, it must be remembered that these men rotated among the 1 0.3 -1.0 amus ' KTEin or rirz covza- tu yUHBEl X- zayxd HiiinEt or caCXS or AsazsTosis Mywin i1- .Mod Ad erate vanced various operations of pipe covering and: were not continually exposed' to high concentrations of asbestos dust as found in band saw cutting and cement mixing. fThe suggestions yfofjYp ' --1> Navy Yard A........... 551 0 0 0 Sr tn grhanst ventilarjon and respiratory protection )m6A -- Navy Yard B.......... ' i " Contract Yard C.... i-' -- frJCantnctYardD... 750 174 168 662 196 168. 0 0 0 0 0 m p w 0 : are therefore of value in maintaining this low /incidence of asbestos^ J0. -0.5 Discussion . ^Totals.................. 1683 1074 0 2 1 The extremely low incidence of asbestosis found, 0.29 per cent, or 3 cases out of 1074 pipe 0. - 0.7 1.4- 2.5 4.7-10.0 f I i:o. - .001 l< r 0. -2. 6 5! .02-0.3 10. -0.6 *3.8 -7:9 ijo. -0.5 --2|0.- '-0:05 1.1 -3.7 I'Q.S -6.8 JO. -1.0 TABLE 5 . coverers, stands in marked contrast to the high kELATiuxsur.1 Between Lesctii up Exposure axu dust concentration found in several of the pipe Incidence of Asbestosis covering operations. As shown, in Table 3, the total dust concentration lor band saw cutting SttlPVAKD ranged from 1:3.1 to 73.0 million particles per cubic feet, for cement mixing from 31.0 to 84.0, and 0-2 2-5 5-10 10 plus for installation on board ship, from 11.0 to 142.0. f Exposed........... 26 13 s 3 Navy Yard A | AfTectcd........... 0 0 o. 0 [Percentage.. .. 0% 0% o% Q% 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 225 435 67 22 Navy Yard B j Affected........... 0 0 0 o [Percentage. ., . 0% 0% 0% 0% 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 [Exposed... Cwtiact -Yard-C- {Affected,.. [Percentage.. 0 105 45 17- demands of ship construction. It is therefore 0... -0- 0 - 1 - apparent that a pipe coverer's environment may 0% 0% 0% 6% change every few days or few weeks at the most [Exposed... 26 118 5 9 Contract Yard D j Affected.... 0 0 2 . [Percentage. 0% 0% 0%`lA2V2'-.I%.; 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 16 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [so/. 28, na. / dust that a worker may breathe over a period of ^unong these workers would have been considerably years. It is further apparent that to obtain such, ^greater. In view of the varied rh&rscter-of the a picture, daily dust counts at each specific 30b '.'environmental dust exposure in the pipe covering in each ship compartment and in the shop together {industry on naval vessels, itis manifestly impossible with the time spent on each job would have to Ho set a threshold. . be compiled separately for each worker. In this respect, asbestos pipe covering differs markedly VI. Conclusions from the asbestos textile industry where dust 1. The character of asbestos pipe covering concentrations for 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 textiles|eannot 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 coverers also apply glass wool, coverers in the shipyards studied was low, 0.29 per rock wool, magnesia, and other types of non cent or 3 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. ;pjt seems is not surprising. ff likely to us that if the pipe coverers studied had 4. Since each'of the 3 cases of asbestosis had ^worked steadily at any of the above operations worked at .asbestos pipe covering in shipyards for rwheie the amount of asbestos dust in the air was more tharijzO years, it may be.concluded that such r consistently high, the incidence of asbestosis pipe covering is not a dangerous occupation. REFERENCES k'fl) Lanza, A. J.: Silicosis and asbestosis. Oxford *'(3) Fahey, J. C.: Ships and. aircraft of the United University Press, New York,. New York, 1938. States Fleet. 2nd War Edition, 1944. Pub Dxexssek, W. C. 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. , `EXPC SMfjl* plate* upon prevalent ot surfaces it measures im application 0 flame, to a di or accompan Shrinking menu or con the operatic) measures are recently prov shrinker dev of nitrogen pc 10 da: '-or Three ^er exposure expe; symptoms, bi following day. The purpose the exjsur mihII, unvent:. The torch < the convcntx In most rnstti annular ring which supplies ul water arout lation of the tc *tcel plate our As with oxyac size of the lord of metal enax ducted on thin: range common! opacity of the * Received for 1 Industrial H;