Document kD0m79y53YovNz9KV225GLzY0

k_ `V >,vf / A HEALTH SURVEY OP PIPE COVERING OPERATIONS IN CONSTRUCTING NAVAL VESSELS* Waites E. Fistsctca,1 Frederick J. Vibes, Jr.,* Robert L. Case* and Pima* Dxinzzz* . | r. " irJ ......rich .< iT*** .. -_C? *w` M, .cite* stave. : tf TcrVs ii Area. g- j .. *.-?at;oa ; .n-se. Arch. I rLOc tab- i ^4 7S3 J, * i1i . i, pyjbbpes! j ,v Tim JtJS: [ 1 ; C. xva Cun- } .ui ae.tccdty J" L-Afrtiiyiaae. j t mm r ^ i. max, i- l~, i riiKS, V, 7.: : -,-yiia: (ethylene j - 4 r.ikuy and the j . J. ?"3neo!. k j 0 :t 1*.*xd CAarzxma, 1 7 4.' carjos tern- | n taj field studies. ! * * !j /U^tsattd'hydJtt- j -ujsuatiad doagea. -.1 j W .\ a K INDUSTRIAL health inspection of an felt and pipe covering in naval work am its low ' r\ important U. S. Navy Contract Yard thermal conductivity, light weight, strength, and *" indicated that dustbess from miscellaneous refractoriness. When the-felt and pipe covering 1 pipe coverin' operations was considerable and that were first developed, we were still buildbg vessels 4 tew o; the employees had what appeared to be under the Washington Treaty of Limitations in asbestos's. This is a well-known baustrial disease Tonnage, and every pound saved meant that much caused by only one tain;--prolonged breathin; of more armor, guns or ammunition for a given asbestos dust. The clbical manifestations arc displacement, to say r.othbg of mom economic .shortness of breath and an unusual chest picture operation for the weight involved b 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 750*F. with which it very properly is classed. ' as compared to magnesia with a weight of 16 It .was not felt that experience b 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 b other yards, and certainly' weighs about IS pounds per cubic foot as compared was no cause for alarm, but the results warranted to 26 pounds per cubic foot for other high temper-, check-ups elsewhere. Accordingly, arrangements aturc insulations. Because of the lower con were made to examine by chest X-ray the pipe ductivity and the higher temperature limit of. covcrers in two Government Navy Yards, A and the amosite type, less of it need be used b a com B, and b two Navy Contract Yards, C and D. bination covering than other types of insulations. Examinations were made of the working conditions The development of amesite 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 b ioakbg such surveys of occupational on destroyer turbbes. The Navy approved the diseases--medical examination of the workers type developed by a manufacturer b 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 field of application enlarged to indude insulation of valves. Strings, flanges, etc. .From An important ingredient of pipe covering the initial destroyer, it has been used on almost material used on U. S. Navy vessels is amosite. all the destroyers built sbee that .time and on This mboral is a magnesium iron silicate of all other combat vessels bull: since before the variable composition. The came is the generic War. one for an asbestos type of fibrous mineral mined Pipe covering was a later development in late in South Africa. 1935 and early 1936. Due to the manufacturing Tie chief reasons for the wide use of amosite problems bvolved, it took a longer time to evolve into a satisfactory shape, and its first use on naval Received for publication September 21, 1945. IVUiuec by permission of the If-S. Navy. The opb- ons and assertions contained herein are the private ones of the writers, and arc not to be construed as ofuriai or relceur.; the views of the Navy Department or the naval service at large. *Comdr. MC, US.N'R, Asst. Chief Health rVnm]r.-.nt Lieut. H(S) USNR, Health Consultant. Linn. K(S) USXIt, Health Consultant. '*Chicr Health Consultant, U. S hfaridat fVmTni. vessels was b 1937. Since that time its use has spread markedly and it was used on the great majority of naval combat vessels bull: 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 lb** to prevent sweating. Eiir fdt had the *u JOURNAL or INDUSTRIAL HYGIENE AND TCXICOIDCV ImLZi. vantage of being combustible 2nd as i; \ras organic, is marked into measured sections cut when it became vet it moulded or rotted and a rotary electric hand saw. Te'e cut twiba. could harbor vermin. At this time res on xollcc up and either used immediately or sta board certain naval vessels convinced the Navy in the storeroom. of the desirability of eliminating any combustible * Usually one to three worses are employe ' material from on board ship. Eventually water- this operation. During the handling, cswtso repellent amositc was made in strips of SO foot and unrolling of-TEe ashesug, considerable 1 lengths and of suitable width to enclose the janscsjNtt.appcas to Settlejeadilv. A very circumference of. the pipe and.enclosed in an water *pray_shoul<] be used for wetting"Sown extremely light-weight muslin to facilitate hand material as a hlgTi velocity spray stirs up d ling and reduce the dust, which the watcr-rc- - Once it is wetted the handling and cutting of pclicr.t agent accentuated. material Causes little visible dust. All of ` four yards surveyed wet down the mwla L DzscaimcN' or Operation's ano Worudcg .material described above. Ekvirokiiekt One NavyYard has an elaborate exhaust sys Asbestosis results from breathing asbestos for the layout table. The entire top of this u fibers of relatively long length, such as IS to 75 is covered with small perforations through wi microns. It is not caused by breathing chopped the air is exhausted. This table is up asbestos fibers of one or two microns (1). large that no more than two-thirds of the to; Therefore we arc concerned with the presence in . ever covered with material and room air is then air of asbestos fibers which can be seen as such exhausted through the other third. While under lew power of the ordinary microscope. velocity or capacity measurements were nx Tac clinical picture of asbestosis can easily on this system, data presented later in the rep be complicated by the presence of diatomaecous indicate that this control measure had a pari earth, a form of amorphous silica, which can effect in reducing the dust count. cause silicosis and is probably a more serious 2. Bond saw cutting health risk than asbestosis. A standard band saw such as is found in wo< Another dust which may be present is magnesia, working shops is used to cut insulation blocks a LfgO, which is in very common use as a heat boards .into deshed shapes. This operati insulator and is harmless. produces'large amounts'of air-borne dust, m; Therefore our analyses were done to indicate of which tellies slowly. Normally there is ot how much fibrous type of asbestos dust was one worker or. this operation at any one time. present in the air breathed, how much silica'was Inasmuch as this is a very dusty operatic present (especially as diatomaecous earth), and the band saw should be enclosed in a room i how cum of the-harmless ingredients like iron itself and slfould be equipped with adequate lo; oxide and carbonates. exhaust ventilation both above and below t Pipe covering may be divided into seven different ' caw table. Bemuse of the mechanical diihculti operations as follows: . ... in locating this exhaust properly, come of t , dust will escape into the air and the operator shou J. Laying out cad cutting - - thcrcforc wear an approved cust respirator. - 2.'Band tew cutting ' .. . 3: Sewing cad preparation *f hoots cad joektit . '4. Coneni piilia; ....' 3. Sewing ottd preparation oj bools end joes. In this operation jacket covers for valves a: 5.'Holding pipe joints are fabricated. The work consists 6. Grinding * ..cutting asbestos doth with share, padding ti 7. Installation an hoard skip1 `jackets with .insulating material, and sewing wi wire or asbestos cord. These operations git 1. Laying cut cndotliing rise to only slight amounts of visible dust, an Rous cf the insulating felt are unwrapped and exhaust ventilation and respiratory protonic unrolled on a large layout table or on the floor arc neither required nor used.' There is usual: of the shop. This material, with the exception a' large number of workers doing this operatic of the type knows as water repellent amositc, is. in one large room. then well wetted with a fine water spray. It i. Cement miring V - -U *^>v fcUt With c*' arc , -S-dy or stacked -; ;rr c~<oycd at ,-u:-'.au7app:n; -ns.at~b!c dust v-r. A very fine riming down the ' ; f-p stirs up dust. js cutting of the jut. Ail of the : the insulating _ ...itr emails: system ' - tap c; this table ..-i lemugh which . jk k sufiicicntly e.\b cf the top is . .rv-nau *3 tr.crcby ( r tiird. IVhue no ; -nats were made . . iter ia the report - ---t had a marked f -aifaced ia woody -- biQoo ar.d , 7ais operation * a-';.-.ir das:, most . .eaT,' there is only ~ - my one time, y - (icsty operation,. ir. a room by v tea adequate local *; .*: toe below the i s-meied amenities > -cjr, some 0: the V .Uieperator should J rat trspimtor. rj /fisa'r ciS-jacieL: 1- tr. for valves and V 'uvork consists of r -fas, padding the .'.and serving with -< epcrst.'ons give - rjllc dust, and s-rintoty protection i There is' usually ^ t this opemtson v .* "* * \ *' J .* For protection and to give a neat napp; earance with glass doth or asbestos doth lor greater :hc insulation on board ship is usually covered strength. The only operations thatproduce much with cement containing a high percentage of dust arc the wrapping ar.d pounding of amositc asbestos fibers. In mixing, the proper amount and the sewing of sections. * *` of water is added to the dry asbestos cement and Nearly all of the compartments on board ship thoroughly agitated with a hoe. Occasionally arc involved in this work, although most of it is small amounts 0: asbestos cement arc mixed ia concentrated in the machinery spaces. Emily . a pail with a trowel. Considerable dust is raised the greater number of pipe covcrcrs work on board when the asbestos cement, is dumped -into-the ship and "relatively few men in the'shop. Thi- mixing trough and during the early stages of spacing of workers ranges from' one or two mixing. 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' cn-ten or more - The dustiness 0/ this operation warrants thc_it$c jobs in the engine 10cm. Temp-waty exhaust of exhaust ventilation or resnimtery p.--,Trrk- . ventilation is seldom used on beard ship for pipe' or liolii. although neither is generalise used. covering and very few of the workers wear respir ' petrographic analyses of asbestos cement in ators. dicate lltat the amount of diatomaccous earth Because of the varied nature of pipe, covering cay be as high as S7 per cent by count. operations in ship compartments, general exhaust 5. Jfolding ventilation is to bc'prefcrrcd. If the compartment Molding is the process of building up the insula is large, such as the main engine room, five air tion to fit odd shapes of boilcrwork and piping. A changes per hour are needed. In small com form is made to the exact shape of the par: to be partments, such as living spaces, ten to fifteen * insulated. Block insulation is laid on, adjoining air changes per hour are required. sections glued together, exposed surfaces sealed with asbestos cement ar.d the whole mold covered H CoiEPOSmON 0? MaTZUjOS Uszd with asbestos doth. When dry, the molded.* According to Navy Specification the rovings insulation can be lifted off the fonn'anc is rezdy 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: 1 operation. Veiy little dust is produced from rh-s operation and no special ventilation or respiratory ., ' Suiea (SiO,) pel- dm: minimum................................ 47-5 protection is required. Iron oxide (Fe,OQ per cent srsuia.:.................. <5X. Magnesium oxide (ligO) per cent minimum. .1... 6X 6. Gntdui; __ 1 Several,svY>'t-ft wV--_;hgtr scrap pieces of Typical analysis of the two types of asbestos , p-.-r- v--r^-rj--nf insulation by^grSctr.g fibers in general use are tabulated below: up this material and using it in the asbestos cement, 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. fliT'crsl ranm exhaust supplied and an approved Clryiiliu Silica (SiO:)................ . 39.05%. Magnesia (MgO)............... , <0.07%. Alumina (Ai,0j)......... 3.57%., Ferric oxide (TctOw,)....... --A Ferrous oxide (Fc=0O))...........J. 2.41%"' iwia 50-2i% .. 3X5% ;. 7X0% .. 33X0% rrt-vmtnr wnp_by..thcjoperator. Sodium oxide (Xa,0).................... .. 2.12% 7. Irjlsllciion 0/ pipe Ottering on hoard ildp Combined water (NjO)..... 14.4S%.... .. 3X0% There arc a. number of operations involved in pipe covering on board ship. Insulation felt is Therefore amositc alone will not comply with wrapped and pounded tightly around large pipes Navy Specifications because of the low magnesia and joints and fastened firmly in place with wire content and must be mixed with chrysotla. or asbestos cord. Pipes and boilers arc covered asbestos to equal or exceed the 6.0 per cent mini with prefabricated sections, which necessitates mum value for magnesia. On the other hand, some hand sewing to fit the sections. Ready, chrysolite cannot be used alone because of its mixed cement is applied to fill in spaces and give" silica content which is below the minimum US & smoother finish. Some insulation is wrapped. per cent specified by the Navy. -The two types .. i . . \F ' .-I .it ' .'i ti i ,. ' |i* . t.i, / * .* .*,* !. . .*,, .iiir.'.si . * ' * 4. . J. . 1 . 12 JOURNAL OF INDUSTRIAL HYCIEXE AND TOXICCLOCV ' ,. j of asbestos fibers must be mixed together in the and sewing were done with a small amount of ( proper proportions to satisfy the values set for space for storage. Cross draft ventilation was magnesia and shies. The amounts" of these provided by open windows on both &ri cf the rr.stcrisis used to form this fixture therefore room. , would be 6--13 per cent chrysotilc asbestos aid Work on board ship was not supplied wifi 1- * 94-37 per cent ar.-.osi:e asbestos. exhaust vcntfiatlan.- ! ," 1These two fibers differ mainly in their physical No asbestos workers were'found wearing rev *. characteristics. Chrysotflc is capable of being pL-a:ors._ readily separated ir.to very fine fibers with a soft ~ V. S. Xerj Yard B. ........................... ...... silky fee!, whereas amositc is harsher and requires There were 50 men working in die shop and 700 more manipulation to fiberixe it. One authority men on board ship. The shop was divided into has stated that the chtysetilc has the finest in four main rooms: Layout, Sewing, Cement, and il. dividual fibers, and amositc the coarsest. 2c- Storage and Band saw combined. With the >i:: TABLE 2 tl .v: li. i -i; j i: t; 4 ) - '-i! -V. .i- i;;.. . ' .. , Stmioav or Materiaes Ussa at Eacs Yam ni Monts tury yaxd a XirrTusi . eumcTTUj: Amositc 58,200 sq. ft. . 50,000 sq. fa 40,000 sq. fa Amosite (water-repellent) Prefabricated sections ' (molded and block) -- ' 600 sq./a . 39,500 linear fa 15,000 sq. fa 1,200 sq- ft. 115,000 linear fa' -- 1,750 sq. fa 12,800 linear fa Asbestos cloth 76,500 s!;. fa 106,600 sq. fa 34.700 sq. fa COimACTTAU* 6,325 sq. fa 3,300 sq. fa ill I! i. Ii .t 25,700 linear fa i I 40,000 sq. fa ^ : t t -4! ii i . ' 1! I ` i! Metallic twiae" Asbestos yarn Asbestos paper Asbestos board Asbestos cement -- 1501b. -- 2,700 linear fa 34,400 ib. > 5,500sq. fa 6,000 sq. fa 13.0C0 lb. \ 4,000 sq. fa 150 sq. fa 57,5001b. 5,500 sq. fa --` `38,5001b. li *5' iI t: \f;-r it cause of this dinerer.ee we may suspect a decided exception of the Cement Room, the doors between*' decrease in the number of respirable fibers (below these were normally left open. 200 microns in length and 5 microns in diameter) The work in the Sewing Room consisted mostly '. I? '. whenever amosite is used in preference to chrysotiie of fabricating and sewing valve boots and jackets.. asbestos. HI. Peps Covering Facltiees at Itmrvm-AS Sui?VAnns U.S. Navy Yard A. . There were 84 men working in the shop and 4G7 men on board ship. The shop was divided AH the cement used on board ship was mixed ia the Cement Room. There was no exhaust yen- Sewing or Cement Room. The band saw w-,* --p-d-p-rf with a flexible exhaust tube above the table and an exhaust around the .blade below the Saw table. The layra-.r --V.V was ccuinnrd with exhaust ventilation as described \i ;4 I" . -into two rooms, one of which was primarily for above. There was no exhaust ventilation supplied storage and occasional grinding and band saw on board ship for pipe covering and np wnrl-o cutting operations. The only mechanical exhaust were iour.~ wearing respirators. ventilation in the shop was provided for the grind- Cerdrssl Yard C. Jsg, mueng anfl banc saw cutting operaticasan^ There were 5! men working in the shop and 123 was inadequate. In the'oiher room layout, cutting on board ship. Layout, cutting and cement :l v j .. t I 1 \ i ( f v l 1 2 i ii ! .Waj rn* covetoxg opexatioxs 15 TAELE 3 CoiuvtstsoK or Eusrtxcss or Various OraAVto.vs p: Each SurrrARO turvxjLXOA ton vaxs s C3FZMXXI&X Toul Ju*i A5bni Taut dux; cUt utrzF' xrrCF t nut &nd cutunr. cutting. Jjto'f.* And MMnCiliOU* #* j. room. 6.1 15.1 . 4.S 31.0 30.0 Qo 'T* 0.35 0.12 .0.03 . 0.2 0.470.0s 4.2 39.5 4.S 34.0 - 2.4 0.23 3.0 0.1 1.7 * o.o; coxtaaci tAta c COVSAaC XaIO Teul dui AlMtlfli ; urrzp 20.5 2.15 73.0 6.19 11.4 0.62 41.3 3.1 -- 14.2 0.8 arret 10.9 i 0.63 -- . 6.0 0.03 32.0 0.01 6.0 0.02 ' Shop average.......................... 30.0 Ship avenge................... 142.0 0.2a' 26.9 0.02 128.0 1.0 2.8 32.0 49.2 2.6 7.6 1.1 . 11.0 0.23 0.03 JieU: il?l'C? -- Million'particles of dust pc cubic foot of sir. TABLE 4 Jncu>e-n-ce op-Asassrosis AroKc'PrrE Covcrcrs vsunrt or nrt covet* Sts KVirost X- XAXXS> srvKicx or ctiu or Aioanrosu Mifll- Mod- Ad* tnol crate vssced ^ JLTC A. 55: 48 0 Navy Yard 3.......... 750 662 0 Caetrict Yard C.... 174 196 0 Centra:: Yard Z>... ies ICS. 0 00 00 0. 1 20 appear that asbestos pipe covering of naval vessels is a rclativciy safe occupation. However, it taus: be remembered that these men rotated among the various operations of pipe covering and were not continually exposed to high concentrations of asbestos dust as found is band saw cutting and cement mixing. Tee suggestions made relative to exhaust ventilation and respiratory protection arc therefore of value in maintaining this low incidence of asbestosis. " Totals.................. 1653 1074- 0 2 1 Dtscusstox The extremely low incidence. of asbestosis found, 0.29 per cent, or 3 cases out of 1074 pipe TABLE 5 covcrcrs, stands in marked contrast to the high BziA-noxidr Bmvzxx Lenctu or Exposure ak dust concentration found in several of the pipe Ixcmuxcc or Assestosis coveting operations. As shown in Table 3, the . total dust concentration for band saw cutting ruu ix nrr corstuco *ourr*Y ranged from 13.1 to 73.0 million particles per KUlrtAto ' cubic feet, for cement mixing from 31.0 to S4.0, and -2 s-to 10 plus for installation on board ship, from 11.0 to 142.0. [Exposed.......... (Percentage.... 26 o 0% 13 S 00 0% 0% The solution of this apparent discrepancy lies in 3 ' a characteristic peculiar to the pipe covering trade, o that is lack of a necessity for specialisation. In 0% general, pipe covcrcrs arc capable of doing all of' (Exposed............ 22S 435 67 22 ` _ the operations described above, and the worker JCavy Yard 3 (AfTccteil.____ _ 0 0 0 ' 0 may l>o changed from one ojxrration to another or (Percentage.... 0% 0% 0% 0% to different jobs in the same type of operation without loss of efficiency and according to the Exposed.... 0 105 45 17 demands of ship construction. It is therefore Contract Yard C < Afleeted.... ' 1,Percentage.. 0 o7o 001 0% 0% 6% apparent that a pipe covcrcr's environment may change every few days or few weeks at the most . 'Exposed... 26 115 5 9 . CoatiacYarT> Affected.... 0 0 0 2 Percentage. 0% 0% 0% 22% with a constant fluctuation in the dust concentre*` tion which he breathes. Therefore, the figures given in Table 3 for shop average and ship avenge . cannot give a composite picture of the asbestos i I 04 I. I >' i ) -r 15- 16 JOURNAL OF INDUSTRIAL SYCUINS AND TOXICOLOGY 2Z, m*. I dust that a worker r.*.ay breathe over a-period of years. It is further apparent that to obtain such a picture, daily oust counts at each specific job among these workers would have been considerably ; < greater. In view of the varied character of the r. ti environmental dust exposure in the pipe covering -in caci ship compartment andjn the shop together industry on cava] vessels, it is manifestly impossible : li with the time spent on each job would have'to " to set a threshold. --. _____ it he compiled separately for each worker. 'In this'. _respeet, asbestos pipe covering differs markedly VL CoN-a.vsiO.N-s , `from the asbestos textile industry where dust ' I. 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, cannot be applied. A further factor in maintaining a low inddcncc 2- The operations of band saw rutting, grinding, of asbestosis is that in band saw cutting, grinding, cement mixing, and installation on ocard ship and cement muting only one or two men arc in should be equipped with exhaust ventilation to volved ar.d the work is-usually done at infrequent keep the total dust concentration low. intervals sucli as several times a week. .... Finaliy, pipe coverers also apply glass wool, rock wool, magnesia, and other types-of nonasbestos insulation, all of which decreases the a. The incidence of asbestosis among pipe coverers in the shipyards studied was low, 0.29 per '-cent or 3 cases out of 1074. In view cf the nature of shipyard pipe covering work, this low incidence * |: i i; i-'i: s* amount of exposure to asbestos dust. It seems is no: surprising. : \\ likely to us that if the pipe coverers studied had 4. Since each of the 3 eases of asbestosis bad"- worked steadily at any of the above operations worked at asbestos pipe covering in shipyards for where the amount of asbestos dust in the air was mere than 20 years, it may be concluded that such consistently high, the incdcncc of asbestosis pipe covering is not a dangerous occupation. REFIRIXCIS Nj !. !l (1) Lakza, A. J.r Silicosis and asbestosis. Oxford University Press, New York, New York, 1933. (2) Dx.7T.vaN-, W. C. et ah: A study cf asbestosis is the asbestos textile induing. Bulk No. . 241, Public Health Service, U. S. Treasury ' .Department, 1S3S. (3) Tastzv, J. C.: Ships and aircraft cf the United States Fleet 2nd War Id;doe, 1944. Pub- - " lished by Ships and Aircraft, 1255 Broadway, " ' New York, .New York. .- ll! ill ij fi illi .T ; in *U' I? If w t_ t;:: %; <; . ?, t i i J: 7 '