Document 6RzbVqe2pL5LO1R0OeMo44jBo

FILE NAME: Owens Illinois Library (OWL) DATE: 1946 DOC#: OWL023 DOCUMENT DESCRIPTION: Article from the Journal of Industrial Hygiene and Toxicology - A Health Survey of Pipe Covering Operations in Constructing Naval Vessels "THE JOURNAL O F t ^ M ' I N D U S T R I A L '. S c i p p i ..-/VV.-fr-f 1 Z n -Y: "'i- :>d -v J5 VOLUME 28 JANUARY, 1946--NOVEMBER,1946 / / / PUBLISHED BY THE WILLIAMS & WILKINS COMPANY Baltimore, Md. *m>-iffy . S&i-J..&.!*. unifiant oK'.iW^cj tvfe 1 dogs u d % : th e results-J? :ot indicate-'i f %d .tnthm of-j *d r a b b i t s ^ `r > ' : V pf?.. Mj Si#?-as.3. > v..tlp--; A H E ^ T O 'S o k ^ it 'o r P IP E C O VERING O P R A ^ O ^ N T ' ; C O N S ^ tlC llN G NAVAL V E ^ E I ^ }'-V .r^ .'-y ^ ^ ^ .r>^ ^ ^ . . W AITE* * l ^ W ^ ' t -^j^ A n a ^ ^WgaegL Ti./'R b W rift K GAi*AND PHlBP'ii)l in e* --.. ..." V. AMN INI)USTMAlTiItb^iftipectii5irdt''aSr feltand pipeoahovreerning' utliawal wotkr,'are ftsvlow; important T7. S/N avy^G bilraiit? Yanf thermal conductivity*-light weight; sttengthj*ndr . mice and * ain e which` | a the u r i n e r a indicated that d tu tin essf^ b iisb e ^ eiraa pipe coming-operations'was cbdsderableajxr'th a t a few of ffie-emptoyeer'hadirif^-hppasrisd to-Be ubestosis. T hisisaw ielPkno'fe^ustriiH isetse caused by only one thin^-prolonged'breathing'of m att asbestos dust.'' axe m shortness- of breath aad'ah''unusdal -chest?picture sgmiQcr for/.i-s by X-ray. -In industry"the.dism e isoften- dis* of sa m p le s/^ abling, but' it is'much lesrtrequenf thani'siiroosis;' the indices.;^ with which it very properly-is'dassedi ^ ' - y * ',i:' A It was not feit thkt erperienc^'ih a- sin'gie ythf was enough to' jiutify any general statements1on": working conditions in o th ary ard V ^d 'certaiid y n s no cause for alarm, bdit-the'rcsnlts warranted' check-ups elsewhere Accordingly, arrangements wee made to1examine By-chest X-ray the pipo a of Peris';' suet. Arch. ' mverers in two Governmimt Navy Yards;-A; and B, tad in two Navy Contract Yards, C-and. D . Examinationswere made of'the working conditions : Sopenatnr^W induding-dust counts of`-die air breathed'Teith' : isopropaaoi microscopic and chemical. analysis of ' the dtast degeneration - itself. * :;r !; .que. Arch- g We would point out th a t7this procedure' is 'olatfle halo- jty . Tms J., 25: S -r * physiological M customary in making sucbsurveya of occupational . mwiinil examination, of 't h e : workers / sad a study of the nature a n d concentration of the contaminants in the air breathed. ' / Tins J., 19: .'.if it* Pu b Covdung Mao tu u,,-:*. :. amd Con- -i ' the toridty M hlotethylene. An important ingredient oi--'pipe covering material used on U. S. Navy'vessels is amosite. Thu mineral is a magnesium iron silicate of variable composition. The name u the generic ut, T. L , .-is? tern, V. T.: me (ethylene 7 one for an asbestos type of fibrousminenl mined is South Africa. ' The chief reasons for the wide use of amosite ity and the 'hannscoL it >OutPEfint, )S . tetra- :.% udies. mated hydro- ^ ntial dangers. .<J bt Received for publication'September 31, 1945. Published by permission of the U. S. Navy. The opin ions sad assertions contained herein are the private ones 0/ the writers, and are not to be construed as otfirial or redacting the views oi the Navy Department or the naval service at large. `Comdr. MC, CSNR, Asat Chief'Health Consultant Lieut. H(S) U5NR, Health Consultant. Lieut. H(S) USNR, Health Consultant.Cuer Health Consultant, U. S. Maritime Commis- refractoriness.1' Whett-the.'flt-and pipe covering were first dvripedvWewerestiir buflding vesaels under1the- Washington. Treaty 'of-Dimitations-in Tonnage, and everypoundsavedm eantthatm uch more armor, guns- or- ammunition. for a . given displacement, to sx y n o th in g 'o f-m o re economic operation for the wreaght involved.in-insulation. Amosite pipe--coveringweighsabour 14 pounds per cubic foot, witbrirtemperature limit o 730*F. as -compared to- magnesia.: with a?weight.o'T6 pounds per cubicfoM ^and*:tempenture limit of ; 5007F. High: tem perature amosite pipe covering'' weighs about l^pottcdsper cubicobt'aa-cO<npared>; to 26 pound*per eubicffoot forbtfierhigh-tempers'- afure- msulationK'vBecause; lower- oar^, ductnrity and 'the- higher temperature lia n t ofi . theam osite type, less of itnedbe-'used in * cbm* bination covermg-than other types of-inxulktions:-! The development of amosite felt sta n e d .in 1934-when a-need existed t.'secure a thermal insulation lighter in- weight' and thermally more efficient than the materials (blocks and cement or asbestos blankets)- which were; then being used on destroyer turbines. The Navy approved the type developed'by**manufacturer in September, 1934. Originally--amosite was used only for turbine insulation,, but it proved so satisfactory that its field of application enlarged to indude insulation of valves, fittings, flanges, e tc From 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 problems involved, it took a longer time to evolve into a satisfactory shape, an d 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 IL . 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 bad the disad- Vi 10 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY (mL 2 t, m . 1 'Jan. 194 w m .p i of being:combustible and as it was organic, when it became wet it moulded or retted and could harbor vermin. At this time fires on board certain naval vessels convinced the Navy of the desirability of eliminating any combustible material from on board ship. Eventually water* repellent amoaite w u made in .strips of 50 foot, lengths and of- suitable width to enclose the circumference, of the pipe and.-, enclosed in an extremely light-weight muslin to- facilitate hand* ling and reduce .the dust, which, the water-re* pellent agent accentuated. ..- L D isq u ra o if or^OrrsLAXioNS amd .W oarw o . . . j.. -Asbestoais. results from.-breathing . asbestos fibers of; relatively long length, such a s 15- to 1& microns. ,I t is not-caused by breathing chopped up `asbestos fibers.oi one .or- two; microns- (1) Therefore we are-concerned with-the. presence hr ttir of asbestoa-fibeia which, can. be-seea. as such -.undeolow poweroLthe ordinarymicrescope. ; . / Thtvclinical picture of. asbestosis can ea^fy. be complicated by^the presence. of diatomaceoua' earth,- .-.form of amorphous silk , which can. , cause: silicosis and: -is probably-; al.more- serious health.-risk than.asbestosis.. :. Another dust.which may be present,is magnesia ,,\MgQr which, is-in- very. common.us:;&s ..a .heat insulitor and is harmless... . $>* Therefore our. analyses were don;to indicato how:much fibrous; type of.-asbestos dust- was. present in. the air.breathed,, how mud*-silica wa present? (especially, as diatomaceou.earth), and how-much. of the harmless ingredients- like:.iron oxide.and c a r b o n a t e s . - ; .. . Pipe covering,may hedivided into seven different operations aa.iollowa::-.;.. ___ s' - ' :ri ai-;r. ,<VL Laying out and cutting., V2. Bond tom ending ' ` r ' ' "`" t . 3. Sewing and preparation of boots and jackets ''A 4zCm*ni mixing " Ilf'S:folding- '---`w - - r * -----------d--:- Grinding->./ ' " ~.T, Installation on board-skip . *l.rLaying outlaid culling . Rolls af.the.insulating felt are unwrapped and unrolled on a large layout table or.on the floor of the shop. This material,..with the exception of the type known as water -repellent amosite, is then well wetted with a fine water spray.. It is marked into measured sections and cut with a rotary electric hand saw. The cut sections are rolled up and either used immediately or stacked in the storeroom. Usually one to three workers are employed at this operation. During the handling, unwrapping and unrolling of the asbestos,, considerable dust arises, b u t appears to .settle readily. A very,fine water spray ahould.be used^(or.wetting down the material as a high .velocity, q u ay stirs up dust. Once it is wetted the handling and cutting of the material causes little visible, dust. All- of the four yards :surveyed wet do*a the insulating material desoibed above*; One NavyYard hasan elaborate exhaustsystern for the layout u b ie The entire top of this table is covered^wifh smalLperforations through which the air/is exhausted. This table is sufficiently largp-that no more than two-thirds of. the top. is ever covered with material and roam air is thereby ^exhausted through..the -other, third... While no . velocity., ox; capacity, measurements were. made on this system, data presented later in the report indicate.that this.control measure had,.a. marked efleebin reducing.the.dust count, . . 2: 3asul saw cutting . ... _ . . _A standard band saw such as is found in-wood* .worUng shops is used to cut insulation,blocks and boards,, into desired shapes. This- -operation produces.large amounts of air-borne dust, most . of. which settles slowly. Normally three is. only qsaworker on. this operation at.any one time-.... ' Inasmuch as this is a. .very dusty operation, tho. hand saw. should be enclosed in a room by itself and should .be equipped with adequate local exhaust ventilation both above and below the saw table. Because of: the, mechanical difficulties in locating this exhaust properly, some of the dustwill escape into the air and the operatotshould therefore-wear an approved dust respirator. .. . Sewing and preparation of boots and jackets In this operation jacket covers for valves and pipe*Joints are fabricated. The work consists of cutting asbestos cloth with shears, padding the jackets with insulating material, and sewing with wire- or asbestos cord. These: operations give rise to only slight amounts of visible dust, and exhaust ventilation and respiratory protection are neither, required nor used. There is usually a large number of workers doing this operation in one large room. 4. Cement misting 'y* Pot p'7 the insu .7; ,`witln c t -asbestos of water thorn ugx ... email aiv .' x pail w !\f. when tb -`'mixing ;- .miring-. V' /separate ';".vlhe.dti3 j-.X of' eshat ' o r both, '7>:-<Petrog VT "dlcate tl ' .may be a SL^foi 7T' tioaitafi 7-:.:fonn.iac -/-'insulated : sections, ^w ith -ash . ;-:'7with-. sal -. insuktic: ;7ta> siz: ^.rlususlly operation :/;.-.opaatisr rpratectw Severe. v|i!'jiefabric H;up-. tins -V cement, >: 7 dustiness `'quoit- in 'exposed. ' 'general r i^ftspirato: - 7,`Tnst There 7 pipeicov wrapped -and joint or. asbest with: prt some ha. . mixed ce M.2, /a jM fl -uhr.**-* ipn_c o v e r i n g o p e r a t i o n s . II. tad cut w ith a l it sections a r e ^ riy or stacked^*! : employed at^ '.y g, unwrapping.- y sidemble d u st$ ^ | . A vety fiae^OT ting down theijSj stus up dustw ll cutting of the*# - All of t h e , ^ the insulating^:! Ki f :xhaust systeia'T] p of this table;#: thzough which,j is sufficiently/! >of the top is'v?,? i sir is thereby*^ '#^ V h ile no ( n made.;|;>' &e report-#5 had a marked;? bund in w ood--i|j :ion blocks a n d y # his operation./- ne dust, m o s tr/|| r there is only# r one time. -'raj isty operation,..!?^ in a room by adequate local tnd below the deal difficulties , some of the : l | operator should -*3s respirator. <ots and jackets for valves and ork consists *__ 1 s, padding the -,t\ ad sewing with In perations give -3 sible dust, and ory protection here is usually 1 ~ , -jperation For protection aad'to give- a?aeatrappearanee the insaiatioa on-board skip is usually covered with cement containing *high.percentage of asbestos fibers. In miring, the proper amount of water is added,to the dry asbestos cement and thoroughly agitated with a hoes. Occasionally small amounts-of. asbestos- cement-sre mixed in s pail with s troweL. Considerable dust is-raised when the asbestos- cement' is dumped into the mixiBg trough and :during the early stages of mixing. Ordinarily ;this process is--done, in- a separate room and'Only-one operatur:is exposed. The dustiness- of this operation warrants the use of exhaust ventilation or respiratory protection, or both, although neither is generally used. Petrographic analyses-of; asbestos-cement in dicate that the amount of diatomaceous earth may be as high as 87 per cent by count. S. folding Molding is the process of building up the insula tion to fit odd shapes of boOerwork and piping. A . form is made.to. the exact shape of..the part to be insulated. Block insulation a* laid on, adjoining-, sections glued' together, exposed: surfaces sealed with asbestos cement and the whole mold covered with asbestos- doth.; When dry, .the molded insulation can be lifted oS the form and is ready to be installed on board ship. This- operation is usually done in. the-shop next, to the sewing operation. Very little dust is produced from this, operation and no special ventilation or respiratory protection is required. 6. Grinding Several 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 dustiness. Normally this job is done at infre quent intervals and only one.-or two men are exposed, but the operatiorf should be isolated, general mom exhaust supplied and an approved respirator worn by the operator. 7, Installation oj pipe catering on board skip 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 or asbestos cord. Pipes and boilers are covered with prefabricated sections, which necessitates some hand sewing to fit the sections. Ready mixed cement is applied to fill in spaces and give a smoother finish. Some insulation is wrapped with glass' doth* dr asbestos^ doth- for greater strength. The only operationrthat produce much dost are the wrapping and pounding of; amosite and the sewing of sections; Nearly all o f the compartments on board; ship are involved in this*work; although mostof-It- is concentrated in the machinery spaces. Usually the greater number of pipe coverersworicon board : ship; and relatively few- men. in- the -shop. .The spacing of workers ranges from one or two men doing a small job in a .living- space to- as many as twenty-or thirty men working, on ten or more jobs m -th e engine room: ^Temporary `exhaust ventilation is seldom used on board ship for pipe covering and very few of the-workers wear respir ators; Becauseof th e varied nature of pipe covering operations in ship compartments; general exhaust ventilation isto.be preferred. If the compartment is large, such as the main engine room, five air changes per hour- are needed.. .In small com partments, such as. living spaces,'.ten to fifteen air changes per hour are required. -. IL Composition or Materials Used _ According to Navy Specification the-rovings of asbestos insulating felt'(amosite) shall contain not less than 95 per cent asbestos fiber of- the following composition: Sales (SiOi) per cent minimum............................ . 47.5 Iron oxide (Fe,0>) per cent maximum.................... 45.0 -Magnesiumoxide (MgO) percentminimum.. . . . . 6.0 Typical analysis of the two types of asbestos fibers in general use are tabulated below: CSntnit Silica (SiOi)..................... 39.05%,... Magnesia (MgO)............. 40.07%.... Alumina (Al,Oi)............... 3.67%...... Ferric oxide (Fe,Os)......... Ferrous oxide (FeO)........ 2.41%' ' Sodium oxide (Na,0)........................ Combined wster (NiO)....... 14.48% Amiti I* 50.24% 3.96% 7.80% 32.00% 2. 12% 3.00% Therefore amosite alone will not comply with Navy Specifications hroause 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 band, chrysotile cannot be used alone because of its silica content which is below the minimum 47.5 per cent specified by the Navy. The two types 12 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY l*aL2S, no. I Jan. 124# of asbestos fibers must be mixed together in the proper proportions to satisfy the values set for "piwia tad silica. The amounts of these materials used to form this mixture therefore would be 6-43 per cent chrysotile asbestos and 94-57 per cent amoaite 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. chrysotile-has the finest in dividual fibers, and amosite-. the coarsest. Be and sewing were-done with a small amount of space for storage. Cross draft ventilation was 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. No? Yard B.- . ... . There were 50 men working imthe shop and 700 men on board ship. The shop .was. divided iota four main rooms.-. Layout, Sewing, Cement, and Storage- and Band- saw combined- With the TABLE 1 Stnouaar or Matzsiazs Uam at Eaot Y u u m x . Motets - - mixing w respinto: procedar fabricstic carried o wan done Materi room am respiretoj through i a part of ....'Thereother the pipe cave walls .aac frequent Amoaite ' Amosite (water-repellent) Prefabricated sections ' - (molded and block) Asbesto*cloth - Metallic twine, .iV, ,- .! Aabeatoa yarn- Aabeatoa paper Aabeatoa board!.;. Aabeatoa cement . XMTYA10A t iim u a i/" 58,200 sq. ft 50,000 ft V : :15,900 sq. f t 600sq.fti /l,2 0 0 sq .it 39,900linear ft. ' 115,000linearf t , 76,500sq,,ft.,'. 106,60Qsq.it ;* ... ill. <-* V. isp b.. .. ...-V./r.-...-.,2,700.linear f t 34,400,1b,; -wr. .5,500 sq. f t ` ,6,000 iq. i t 15,000 lh.- OQirttACtTAJUIe ewoucruuusn 40,000 sq .it 6,325 sq. ft - r-- -v - 3,300 sq. ft : 1,750sq. f t = 18,80,linearft -15-700linear f t 34.700sq.it 40,000 sq .ft. . .. . . A; . ` ' f - ; '4,000 sq. i t 5,500 sq.ft 150sq, ft- -' . ' --- v 57,500 n>. : 38,5001b. applied k .Cottine ' /-There .1-wotkingc .> .'were done .K it jacke ^fabricated -^.smaller si vand catti: <* net. fire-f /I'tn eitk ers /o n b o a rd * .' 'In a comps ,. ; who were r.. mao who :'was no ba TV, Anat cause of this dbfereslce 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 chrysotile asbestos.; IIL PlPS COVBUNO FaCTLITIES AT IOTJVIDTTAI ' ' ' - SatWAxas - * : V. S. Novy Yard A. .There-were .84 men. working in the shop and 467.men on'board-.ship. The shop was divided into two rooms. one oi 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 betwees, these were normally left open. ... :.-:v There a: . .The work in the .Sowing Room consisted mostly ; Tor safe - d of fabricating and sewing,valve boots and jackets. - Dreessen. e All the cement used on board ship was mixed is . the asbest the Cement Room- .. There was no exhaust ven- particles o: tilation for either the Sewing or Cement Room. `..'for-that ir The band saw was equipped with a flexible exhaust .:' lhat the a. tube above the table and an exhaust around the ... ingjndustx blade below the saw table. The layout table . In textile was equipped with exhaust ventilation as described. specific jot above. There was no exhaust ventilation supplied for-some ; on board ship for pipe covering, and no workea rotate betv were found wearing respirators- ' large ship Contract Yard C. - in dust exp There were 51 men working in the shop and 121 In cone on board ship. Layout, cutting and cement coverer's r r - r.->- tiH amount' t mixing were done at one end of. the'shop. 'D t a C beatos donfent,' rtngingfrom SS per cent magnesia ventilation wsai respirators were occasionally- worn during these, (10-15%" asbestos)* to amosite (95% asbestos). 3th sides of tbef procedures. At the other end of the shop the When asbestos cements contain large amounts fabrication of boots, jackets and molds w en of diatomaceous earth there is a resultant silicosis supplied Carried o u t A small amount of such fabrication hazard as indicated above.' was done on board ship. In general we feel that dust counts1below 5 od wearing Material was cut with a-band saw in a separate -; million partides per cubic fo o t' by Kodimeter mom and the operator wore an approved dust indicate good dust control'. Tespirator. The dust from this saw was exhausted Our figures in Table 2 were determined by the he shop and TOO?-* through a slot under the table which caught only. *Konimetex and nor with the impinger instrument, /as divided int a part of the dust given off above the table.. . We used the Konimcter because it is light, easily g,' Cement, *bNL There was ho exhaust ventilation us the shopY. portable and takes records w h id t'can b e kept ied.: With t h e S other thin-for the band saw, and'none for th e ` indefinitely. As is indicated .in'; T a b le '3 , the pipe covering operations on board ship. All Soon, dustiest operations are band saw cutting, cement walls and niters of the* shop, were- cleaned a t mixing, and installation on board sh ip ..... . .. n u s va frequent intervals. with an- industrial vacuum deuier. Most pipe covering on board ship was applied in the evening during the second shift. .V /M edical F erneres The incidence of ssbestosis among pipe coverers 6,325 sq. Cmtnet Yard D. as determined by chest X -ray is-giverr in Table VsTi There were 8 men in the shop and 160 men 4/ The relation between yearsjoi exposure and working on board ship. Pipe covering operations per cent asbestoait b included in Table 51 ' were done in.two shops. In the main one, boots * . Due to frequent turnover of. shipyard workers Hid jackets for pipe valves and connections were and the length of time required to X-ray a large 15,700 Unese frit*? fabricated, and surplus material stored. In the number of workers, the number X-rayed may not 40,000 sq. smaller shop the operations consisted of layout .equal.the number of pipe coverers.- At Contract tad cutting of amosite, water repellent amosite . Yard C X-rays were examined of men-who had left and fire felt. There was'no exhaust ventilation - the yard while a t Navy Yard B a few pipe.coverers la either shop nor for the pipe covering operation were not: X-rayed. At Navy Y ard A- the 48 oe board ship. All theasbestos cement was mixed X-rayed out of 551 were all.older men-working 5,500 sq. ft. ''&> la a 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 of amosite. There 'experience in the asbestos industry, but'the tables 38.500 lb. _ _ _ _ _ _ __Y.fi ie .doors betweettjjf r.| consisted mostly-^ oots and jackets- .ip was mixed is?; no exhaust 'vn-rg Cement Roora.fv| a flexible exhaust 3 laust around th * ^ he layout tabi:.'5 ii.on as described^ ntilation supplied it. a-**^o worker^ was no band saw cutting of asbestos in this y ard / / IV. Analysts o r Settled D ost and Dost Counts / / There are no established figures forfiermissible or safe dustiness in pipe covering operations. Dieessen et aL (2) in their study of asbestosis in the asbestos textile industry suggested 5 million particles of total dust by impinger as a threshold ^ i n j u r y . We should like to point out ^ jj^estos textile and asbestos pipe cover ing industries differ widely in their dust exposures. In textile plants workers usually continue at specific jobs with fairly constant dust exposures tor some yean, whereas the pipe covercr may route between shop and ship and from small to targe ship compartments with a wide variation are based solely on shipyard' exposure. At Contract Yard C, for example, the Asbestos Shop estimated that about one-third of .their pipe coverers had worked with asbestos before coming to the yard. The one case of advanced asbestosis at Contract ' Yard C had worked in the asbestos industry for 23 yean before coming to work in the yard. At Contract Yard D the two cases of moderate asbestosis had worked 22 years and 30 years at pipe covering in their yard. All of the X-ray films used in the above data were fint read by roentgenologists of the Medical Department of the yard and then by one of the authors (VY. E. F.). Dr. W. C. Dreessen, U. S. P. H. S.t was kind enough to examine the three positive plates and he agreed on the diagnosis. -ir STshop and 123:$ ng and cementar. in duat exposure. la contrast to the textile worker, the pipe rovtTer's materials differ markedly in their as- Since only three workers out of the 1074 X-rayed had asbestosis, and each of the three h id been a pipe coverer for more than 2ff years, it would *5 *r'r 'l l # * *>?>;> vt; >nrr.w' sk--. TABLE 2 Analysis o r S t m t s Dtjst and Aia Saxtus /<uuJ9*S] QRIARe ; ' 3 r8* m cxkt uus TiAJi io lOCBOMBYCOOITY J1o * Stozi w 2 1m a * 1 8 8 s' to* 8 08 3* GmMM U ai & 8-3 1 | l to u 1* a* to- n 5 8 ** rl 3 3 'r & ear a t m OiPPCn* Total dtut lUafi of Avereouou no jlojutoi ever Etne* of Avtf . eooftU .. m art tflllTOt (04) Layout and cutting .Navy Yard A............ ......... 95 16 6 12 6 ,:Navy Y ardB ...................... 98 10 8 12 tr. | Contract Yard C . 95 30 5 10 tr Contract Yard B .. . . . 95 26 6 8 tr 24 26 10 2 3.5- 8.7 6.1 0.21-0.50 0.35 5.7- 6.0 40 18 12 7 1.6- 6.5 4.2 0.01-0.5410.23 0.6- 7.9 26 14 15 4 17.1- 25.2 20.5 2.13-4.30 2.18 6.6-19.5 29 21 10 5 6.5- 16.5 10.9 0.09-1.16 0.63 1.4- 8.7 ' - Layout and Band taw cv Sewing and Cement mix Grinding... General root Cutting with band taw - --* ` - Navy Yard A ... **1 *. f- *' 2 ll.O ^lir.2 15.1 0.10-0.14)0;12 0.7- 0.9 Navy YardB...................... 98 9 7 8 tr 48 16 12 2 3Z.4- 46.6 39.5 2.8- 3.2 3.0 6.5-8.7 Contract Yard C.......... 98 9 63 2 tr 10 -.4 12 -a 18.2-100+ 73+ .9-12.8 6.19 4.3-12.8 Shop aver Ship aver i SetK l Maiding operations - Contract Yard C...... .......... 98 Contract Yard D ;.. . . . . . . . 95 / 8 .66 3 tr 7 10 4 9 7 tr J * .10 12 ; or? T .t c a uoex ; Sewing tc prep, of boots & / > . .men* '' jacket " . ' . ` * ' ` "Navy Yard A'.. . . . . .V. * * 2 3.5-' 6.1 r4.6 .01- .06 0.03 0.3 -1.0 '" Navy Yard B (Sewing as- - ' ; ' '- ' ..N a v y Yard - 'bestoe cloth)' ~ 98 '12 A t 9 t r 42 21 16 3 3:3-* 6.0 6.8 0.0- 9.4 [0.1 0. -6.4 'N a v y Yard (Stuffing withmnorfte)... 98 V8 >8 :ll tr 38 20 .15 1 2.1f ** 2.1 0. . 0.3 0.. Contract Yt Contract. Yard C......... . . . . . 95 26 /.6 11 3 . 28 .12 :14 2 10.6- 12J 11.4 .4S-V.79 .62 3.7 -7.4 . Contract.Yt V;.ContractYard B- . , . . 98' ! 6 6 8 f* 38 28 14 5 3.9- 10.9 6.0 0. - .05 .03 0,. -0.5; Storeroom ( . T o tals... .. 'C ontractY ardB I..1 .95 .15 i`.8- 7 tr 26 .32 .12 Cement mixing ' .Navy Yard A .'.............. ..... ^ 4* v,:Navy Y a r d B . . : . . . ; ......... w `Contract Yard C ..........1 ... * * Contract Yard B (on board ;*;v ship).;.. . . . . . . . . . . . . . . . . . : : * .Grinding scrap material ....Navy Yard A ...................... 88 8 20 16 1 16 5.4- 30+ 31+ 0. -0.52 0.2 0. - 0.7 . 2 67. -100+ 84+ 1.6 -1.7 1.7 1.4- 2.5 2 33.8- 48.7 41.3 1.6 -4.7 3.1 4.7-10.0 RXtASuXSr 10 33 5 19.6- 40.0 32- 0. * 12 15 9.4-100+ 50+ 0. - .02 -1.6 .01 0. - .001 .47 0. -2.6 Navy Yard General; room " 1Navy Yard A.............. . i . . Navy Y a rd B .................... 4 Contract Yard C ............. - Contract Yard D.; . . '. . . . . 49 & ' 2 4 5 0.2- 24.6 10.0 0i -1.4 0.08 .02-0.3 1.6- 3.3 2.4 0. - .01 .0110. -0.6 0.0- 21.6 14.210.34-1.7 .8 13.8 -7.9 3.9- 10.9 6.0 0. - .05 .02:0. -o.$ 1 Aboard ship .... Navy Yard At................... Navy Yard B . . ................... _ .Contract YardC................ Prm+mrf Viird D................ 1 30 65. -250. 142 0. -0.17 0.02!0. -0.05 15 84.4-192.01128 1.36-5.212.8 il.l -3.7 15 25.3- 89.0149.210.23-2.3811.1010.5 -6.S 15 * j-y u n n:n. -nuln.rtvo. -t a * r*" ' i * S o tti M FFCF -- Million particles of dust per cubic (oot o( air. 14 Navy Yard Contract Y. Contract Y; f . PIPE COVERING O PER A TIO N ^- 15 ... " : - 1 TABLE 3-, ' ? Compaibon or DcaTuum o r Vabious Ostoateoks or Eaot,Shotasd- '',>>- .. 0.30M.35I 5.7- 6 . 0 , ||g n.54 0.23 0 .6 - 7 . 9 - f p -.30J2.18I 0.631 1.4- 8 .7 -S & .120J . 7 - 0 . 9 ^ 6.5- 8 . m 4.3-12.8. | onunoi XATYYASBA - Total dust Asbestos dost Layout tad cutting. jrwer* . 6.1 0.35 It 1 Sewingand fabrication........... . 4.8 0.03 Ceaeat mixing........................ .31.0 0.2 Crioding................................... 50.0 0.47 General room.. . . . . 10.0 0.08 XATTf ASP> w;cmmAcz YABPC coimAcr t a s o d T a tti dut AadboCiMtM. Tatti dost .Asbesto* _ dost Total`dust .Asbestos, dun , itrer .. 4.2 ;o:23 to e 4.8 .0.1:.. 84.0 1.7' - strrer . -,.20,5 2.18 n .11.4 0.62 41.3 .3 .1 .u rre r... -10.9 0.63..: .6.0 0.03 ! 32.0. ; 0.01 2.4 0.01 14.2 ;- o .s ;\ '6 .0 0.02 Shop avenge.. . . . . . . . . Ship average........... 30.0 142.0 0.25 0.02 26.9 1.0 3T.0 2.6 128.0 2:8 - . ' 49.2 ' - r : l . Vote: MPPCF - Million p u tid a of dust per cubic foot of sir *- 7.6 0.23 ' ll-.O1 0.03 - ,0610.03 K9A -6 .* - .791 .6213.7 - .05 .030, -O.S -TABLE 4 iHooctCE or A ax sio ss Auotn P x n C ovxuss VTABP mm PUMSSS Of CAflSS potesti or.ASBttroiKs , o rn n com XSAT SIS Mini* Mod* Adw m X onto vtaced Navy Yard A.......... 551 48 0 0 0 . Navy Yard B.......... 750 662 0 0 0 Contract Yard C .... 174 196 0 * 0 1 Cootract Yard D ... 168 168 0 . 2 0 1683 1074 0 2 1 -0.3:20 .2 0. - 0.7 -1.7 1.7 1.4- 2.5 * a -4.7 13.1 4.7-10.0 ;va - .02! .01 0. - .oot?l TABLE 5 / R tunom sar Bottom Lznctu o r Expospxz and Incidence o r Asais tos a YtASpor r o t covncfo 1X9V9T1Y Z ----------------------- - J* 0-1 2-5 J-10 to plus - 1.6 .',7:0 . -2 .6 S S . . m -1.4 0.081 .02-0.3 - .011 .0110. -0.0 .V* -1.7 i .3 13.8 -7.9 .{ -- H -- - .OSi .0210. -O.S / W o. -o .o s^ > ,1 . 1 - 3 . 7 ; ^ j-2.38|1.10;0.s -6.8 -0.2l!0.03!0. -1.0 **-> Navy Yard A R ipovd........... Affected........... Percentage.. . . Navy Yard B Exposed........... Affected........... Percentage.. . . [Exposed.... Contract Yard C <Affected-- [Percentage.. fExposed. . . Contract Yard D j Affected-- [Percentage. 26 13 8 3 0 000 0% 0% 0% 0% 225 435 67 22 0 000 0% 0% 0% 0% 0 105 45 17 0 001 0% 0% 0% 6% 26 118 5 9 0 002 0% 0% 0% 22% appear th at asbestos pipe covering.of naval vessels is a relatively safe occupation.- However, i t must be remembered th a t these men rotated among the various operations of pipe, covering and.were'not continually exposed to high, concentrations., of asbestos dust as found :in band saw catting and cement mixing. The. suggestions, made relative to exhaust ventiktion and. respiratory protection are therefore of value in maintaining this low incidence of. asbestosis. ` .7 ' ' .._f . D iscussion The extremely low incidence of asbestosis found, 029 per cent, or 3 cases out of 1074 pipe coverers, stands in marked contrast to the high 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 13.1 to 73.0 million particles per cubic feet, for cement mixing from 31.0 to 84.0, and for installation on board ship, from 11.0 to 142.0. 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 demands of ship construction. It is therefore apparent that a pipe coverer's environment may change every few days or few weeks a t the most 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 t v> dust that a worker may breathe over a period of among these workers would bave been considerably \ yean. I t is farther apparent th at to obtain such . greater. In.view of the.varied: character of the a picture, daily dust counts at each specific job environmental dust exposure in the pipe covering 1 in each ship compartment and in the shop together industry on naval vessels,it is manifestly impossible 'v with the time spent on each job would have to. to set a threshold. be compiled separately for each worker. In this respect, asbestos pipe covering differs markedly VI. Conclusions Section from the asbestos textile industry where dust 1. The character of asbestos , pipe covering concentrations for an operation do not fluctuate industry oo 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 incidence 2i The operations of band saw cutting, grinding, v:,^ju*tes of asbestosis is that in band saw cutting, grinding cement mixing, and installation on board ship . preval and eewwnt mi-ring only one or two men are- in* should be equipped with exhaust ventilation to y.sariac volved and: the workis usually done a t infrequent keep the totaj,dust concentration low.. >*yw ti intervals such as seven! times a week. 3. The.-incidence of. asbestosis among pipe*. `V^applic Finally, pipe coverers also .apply glass wool, covejers in the shipyards studied was low, 0.29 per J,'. flame. rock, wool; magnesia, and, other types of non- am t or 3 cases out of 1074. In view of the nature <;V , or u x asbestos insulation, all of which decreases the y v t shipyard pipe covering work, this low incidence ; 'amount ofexpcsuretoaabestoadust. Itse e m s likely,to- us that if- the pipe*coverers-studied $4*1 worked' steadfiy-at any of* th e above operations where*the amount of asbestos-dust-in the.dir was consistently high, -the- -incidence- of .asbestosis is n o t surprising.. ~ T 4. Since each of the 3 cases of asbestosis bad hflw worked a t asbestos, pipe covering in shipyards for - more than 20years, it may be concluded that suck .. -'recent ' pipe coveringis not a dangerous occupation. V*'?almnfr -.v v -y r ; - P r e f e r e n c e s ^ .. ,'o in itr . . V ::V-1 0 da; . (1)'lanza,^'A. *J.: Silicons an<L aabeitoaa. Oxford " (3> F a n * . J. C.: Stipmaad aircraft of. the United ; ;^ ;T bree ;:'V '-University Press, New York, New Yotk, T938. ) : States Fleet, to d War Edition, 1944. Pub- :>rexpst ; I}. pxxxsser, W. C. etal;;A tody of aabeatoa . habed by Ship and Aircraft, 126$ Broadway, > sympt -'-* in* the asbestos textile industry. Bull. N a . ,, ' New York, NewYoric - 241; .Public Health Servie^ U. S. Treaaiury J - 'Department, 1938. .- .''* '. ' .follow: rhTaz v-the x sssu, V. The the^*c In me annuli ' which of wa;' tation *tecl p . A* wi sise of p{ me ductec range capad Rr