Document 91jjK6R8J72LedgXoQvN5jEzp

FILE NAME State of the Art Literature SAL DATE 1946 DOC SAL044 DOCUMENT DESCRIPTION Journal Article - A Health Survey of Pipe Covering Operations in Constructing Naval Vessels VOLUME 28 JANUARY NOVEMBER 1946 : PUBLISHED BY THE WILLIAMS & WILKINS WILKINS WILKINS COMPANY COMPANY Baltimore Baltimore , Md . eet bel ie tg nasdecgs OF PIPE IN oH y EALTH COVERINGOPERATIONS CONSTRUCTING NAVAL VESSELS |)... AND vee VILES ROBERT L. GADE J. FREDERICK FREDERICK ete aay aed AN INDUShTealRth IinsApeLction an important U. S Navy Contract Yard indicated that dustiness miscellaneous pipe covering operations consid^'rableand that a few of theemployehrasd what appeared to be asbestosis This a industrial caused by only one thing prolonged breathing of asbestos dust The manifestations are shortness of breath and unusual chest picture . by ray In indutshetdirseayse often dis- abling butitbutit is much frequent thansilicosis with which it very properly classed Va It was not felt that experiencine a single yard was enough to justify any general statemenotns were made to examine chest ray the pipe coverers in two Government Navy Yards A and B and in two Navy Contract Yards and D. Examinations were made of the working conditions including dust counts of the air breathed with microscopic and chemical analysis of the dust refractoriness When pipe covering . were first developed we were still building vessels under the Washington Treaty of Limitations in Tommage and every pound saved meant that much more armor guns or ammunition for a - given displacement to nothing of more economic in operation for the weight involved insulation Amosite pipe covering weighs about 14 pounds p^rcubic foot with temperatliumitroef750 compared to magnesia with as weighoft 16 _ pounds per cubic temperatur limeit of ' weighs about 18pounds per compared : to 26 pounds per cubic foot for other high tempers a ature insulBaect ausi e oof nthselower 2 the higher ductivity and temperature limit of - be amosite type less of need used in come - bination covetr hanionthg er types of insulations The development of amosite felt started in 1934 when a need existed secure a thermal " insulation lighter in weight and thermally more efficient than the materials blocks and cement or eee Neha Meyne gt ik fend 7: MW RY that this used We would point out procedure is asbestos blankets which then being on destroyer turbines The Navy approved the such surveys customary in making of occupationaloccupational of the workers type type developed by manufacturer in September medical examination 1934. Originally amosite was used only for concentration and a study of the nature and of ~~" turbine insulatibount it proved so satisfactory the contaminants in the air breathed that its field of application enlarged to include 1. AND CON- -- the toxicity te blorethylene oA of pipe An important ingredient material used on U. S. Navy vessels This mineral is a magnesium covering is amosite iron silicate of insulation of valves fittings flanges etc. 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 * RAIN T. L tes HELD V. .: Cato ine ethylene ity and the BU Pharmacol & . rd AN a " CARPENTER \ tetra- res) ? g Ss budies 21% . 3.6 nated hydrontial dangers SEASa te variable composition The name is the generic one for an asbestos type of fibrous mineral mined in South Africa The chief reasons for the wide use of amosite the Received for publication September 21 1945 Published by permission of the U. S. Navy The opin- ions and assertions contained herein are the private ones of the writers and are not to be construed as othicial or reflecting the views of the Navy Department or USNR naval service at Comar MC large ; Asst Chief Health Consultant Lieut H USNR Health Consuitant Commis- Lieut H USNR Health Consultant Chier Health Consultant U. S. Maritime sica 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 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 I. 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- 4 t 10 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY 20 28 no 1 vantage of being combustible and as it organic when it became wet it moulded or rotted and could harbor vermin At this time fires on board certain naval vessels convinced the Navy is marked into measured sections and cut with 2 a ' a rotary electric hand saw The cut sections are ~:' *- immediately rolled up and either used in the storeroom or stacked of the desirability of eliminating any combustible material from on board ship Eventually water- Usually one to three workers are employed at ~ this operation During the handling unwrapping -: repellent amosite was made in strips of 50 foot and unrolling of the asbestos considerable dust lengths and suitable width to enclose the circumference of the pipe and enclosed in an arises but appears to settle readily very fine water spray shoulbde used wetting down the |. extremely weight muslin to facilitate hand- material as a high velocity spray stirs up dust 7, ' DESCRIPTION OPERATIONS AND WORKING four yards surveyedsurveyed wet which the lingand reduce dust pellent agent accentuated _ water . be I. Once it is wetted the handling and cutting of the material causes little visible dust All of the 2 down the insulating The Asbestosis breathing . oecp ENVIRONMENT results fromlength |One Navy Yard has elaborate exhaustsystem , asbestos for the layout table The entire top of this table fibers of relatively long length such 15 75 is coveredwith small.perforations through which microns.. It is not caused by breathing chopped asbestos fibers of one or two microns 1 | Therefore we concerned with the presence in >air asbestos.fibers which can seen such large exhausted exhausted than thirds suficently suficiently the airexhausted 7 This table is sufficiently * of exer covered with materiaanld room air is thereby exhausted thr theootu her g thih rd Whinlo e_ under low power of the ordinary microscope easily The clinical picture of asbestosis can . velocity or capacity measurements were made ' on this system data presented later in the report =, be complicated the presence of diatomaceous indicate that control measure had a marked sections effect reducing dust count earth form amorphous silica which can in 7. EE probably standard band saw such is in wood- Te hceaaulstehsriilsikcostihsaannadsbiesstosis 2:5... moYreaeh se0r"i:ous * A .; Band cuting ss asp, found ; MgO which is harmless cbeommon magnesia working shops used present shapes This operation weredone _ Another which may - insu andlisahatrmoler ss were . Therefore our analyses is is to cut insulation blocks and ; as heat ws cee boards into desired ; produces large amounts of borne dust most - * to indicate of which settles slowly Normally thereonly : time one worker on this operation any operation itself and should equipped with adequate local one howmuch fibrous type of .asbestos dust | was at dusty present in the airbreathed how much was ~ Inasmuch as this is a very as : present especially diatomaceousearth and band saw should be enclosed in a room by : - the | much of harmless ingredients like iron - oxide and carbonates te ba. Sees . , exhaust ventilation both above and below the . be saw table . Becausoef the mechanical difficulties - opPeirapteiocnosvering may divided into seven different as follows out king bere teDsaw .2 s T e h diunsltocwialtlinegscatpheisinteoxhtaheusatirparnodptehrelyopesroamte or osfhoutlhde, ..: Laying cutting 1. out and "* Hitec v wean. therefore wear approved dust respirator .2. Band saw culling 3. Sewing and preparation of boots and jackets * - 3. Sewing and preparation of boots and jackets - In this operation jacket covers for valves and | 14 Coment mizing 0 8095 Molding 6. Grinding oud;fase citi Ee ee pipe joints are fabricated The work consists of respirato cutting asbestos cloth with shears padding the 1D '* ^ There Installation board jackets with insulating material and 7.ae ship sewing with on re Palb)o. +) +.. , wire or asbestos cord . These operations give .1 Layingout andcutting 3% 1. rise to only slight amounts of visible dust and unwrapped - Rails of the insulating felt are and exhaust ventilation and respiratory protection unrolled on a large layout table on the floor are neither required nor used There is usually pipe cov - wrapped and join or asbes of the shop This material with the exception a large number of workers doing this operation - of the type known as repellent amosite is then well wetted with a fine water spray It in one large room 4. Cement mixing mized ce : ag S (te on ye SS re (3h ae Fes aN toa fof rs ty hat he ae wide ai SS ws gute s aS be ae KENEY PE Jan. 1946 te te es PIPE COVERING OPERATIONS - . cut witobhs and it sections are ely or stacke:d : employed at 3 4 g unwrapping+. siderable duste A very finews finews ting down the stirs up dust cutting of the h : For protection and to givea appearance the insulation board ship is usually covered with cement containing a high percentage of asbestos fibers In mixing the proper amount of water is added to the dry asbestos cement`^nd cement`^nd thoroughly agitated with hoe Occasionally with doth or asbestos cloth for greater strength - The only operations that produce much of dust are the wrapping and pounding amosite t and the sewing of sections I Nearly all of the compartements on board ship are involvedin this work although most of it small amounts asbestos cement mixed in concentrated in the machinery spaces Usually a pail with a trowel Considerable dust is raised when the asbestos- cement is dumped into the the greater number of pipe coverers work on board . ship and relatively few men in the shop The mixing trough during the early stages of mixing Ordinarily this process done in a spacing of workers ranges from one or two men doing a small job in living space to as many separate room only one operatoirs exposed The dustiness of this operation warrantthse use of exhaust ventilation or respiratory protection as twenty thirty men working on ten or more jobs in the engine room Temporary exhaust . ventilation is seldom used on board ship for pipe very theworkers or both although neither is generally used covering and Petrographic analyses of asbestos in ators -..-' few of : wear respir- dicate that the amount of diatomaceous earth varied may be as high as 87 per cent count 5. Molding - by ~ Because of the nature of pipe covering operations in ship compartments general exhaust _ ventilation is be preferred If the compartment Moldingis the processof building up the insula- - is large such as the main engine room five air tion to fit odd shapes of boilerwork and piping A changes per hour are needed In small com- This operation a3 ne dust most thereis only * one time isty operation . in a room by | adequate loca.l* Ty and below the tical di^-cuities- some of the au . aKS: operator should. respirator ro ots and jackets for valves and .~ ' ork consists of . bal 3 padding the + & nd sewing with ~ perations give sible dust and: - ory protection here is usually operation form is matd o te he exact shape the part to be insulated Block insulation laid on adjoining sections glued together exposed surfaces sealed with asbestos cement and the whole mold covered with asbestos cloth When dry the molded insulation can belifted off 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 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 two men are exposed but the operation should be isolated general room exhaust supplied and an approved USED spaces fifteen partments such as living to | air changes per hour are required .... II COMPOSITION OF MATERIALS USED According to Navy Specification therovings of asbestos insulating amosite shall contain not less than 95 per cent asbestos fiber of the following composition Silica SIO per cent minimum + 47.5 Lon oxide Fe per cent maximum 45.0 Magnesium oxide 3g0 cent minimum 6.0 ' Typical analysis of the two types of asbestos fibers in general use are tabuiated below . Chrysotile Amosila Amosila Silica SiO . 39.05 .. 50.24 Magnesia MgO 40.07 eee 3.96 Alumina A10 3.67 cece erence eee Ferric oxide Os Ferrous oxide FeO 2% 41 eeeas 7.80 32.00 respirator worn by the operator 7. Installation of pipe covering on board ship There are a number of operations involved in pipe covering on board ship Insulation felt is wrapped and pounded tightly around large pipes andjoints and fastened firmlyin 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 3 smoother finish Some insulation is wrapped Sodium oxide NO NO 0... Combined water ene e cece eee eee 1 4.48 . 2.12 3.00 Therefore amosite alone will not comply with Navy Specifications because of the low magnesia content and must be mixed with chrysotile asbestos to equal or exceed the 6.0 per cent minimum value for magnesia On the other hand 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 ? 2 URS de vol 28 no 12 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY Jan. 1946 of asbestos fibers must be mixed together in the and sewing were with a small amount proper proportions to satisfy the values set for magnesis and silica The amounts of these materials used to form this mixture therefore would be 6-43 per cent chrysotile asbestos and - 94 5p7er cent amosite asbestos These two fibers differ mainly in their physical characteristics . Chrysotile is capable of being space for storage Cross draft ventilation wu : provided by open windows on both sides of the room Work on board ship not supplied exhaust ventilation. was with found were No asbestos workers pirators wearing res respirato procedur fabricatio carried o was done Materi readily separated into very fine fibers with a soft silky feelwhereas is harsher and requires more manipulatitoon fiberize it One authority has stated that the chrysotihlaes the finest individual fibers and amosite coarsest Be- working shop and 700 U. Navy Yard B . There were 50 men in the men on boasrhd ip The shop divided inta four main rooms Layout Sewing Cement and " respirato 2. throughi part of . There Storage and Band saw combinedWith the ather the ~ pipe te i lela " cove walls an SUMMARY OF Materials USED AT EACH YARD MONTE - frequent | , : - ne XAYY YARD Amosite 9077 | 58,2s0q 0ft _ KAVE TARD B CONTRACT YARD G _ CONTRACT TARD D 50,000 sq ft | 40,000 sq | 6,325 sq ft cleaner S applied i Amosite repellent f 15,0s0q f0t hee fer MS HE sq 3,300 " Prefabricated sections ~ 60 sq0 fti | 1,20f 0t 1,750 cde. mold andebld ock . | 39,900 linear it | 115,000 near it | it 18,800 | - 15,700 linear it Asbestos cloth - |, 76,500 | 106,600 | 34,700 | 40,0sq0f0t Asbestos board |, 2,700ft [ 16,0s0q 0ft 7 150 sq ft Asbestos cement ye} 34,400 oy | 15,000 lb =] Ib 57,500 > 38,500 lb. cause of this difference we may suspect a decided decrease in the number of respirable fibers below 200 microns in length 5 microns diameter in whenever amosite isused in preferencetochrysotile asbestos III PIPE COVERING FACILITIES AT INDIVIDUAL U.S.Navy U.S.NavyU.S.Navy Yard A. _ . There were 84 men 467 men working the board in shop and The shop was divided into two rooms one of which was primarily for storage and occasional grinding and band saw cutting operationThse 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 the between exception of the Room doors - these were normally left open The workin the Sewing Room consisted mostly There a for safe d - of fabricating and sewing valve boots and jackets Drecasen particles All the cement used on board ship was mixed in . the asbest the Cement Room . There was no exhaust ves | o tilation for either the Sewing or Cement Room_ for that in ~ The band saw was equipped with a flexible exhaust that the a above the table and an exhaust around the iog indust blade below the tab tabllee| The layout tabl - In textile was equipped with exhaust ventilation as described . specific joi ' above There was no exhaust ventilation supplied on board ship for pipe covering and no worken were found wearing respirators \ some - rotate bet .. large ship Contract Yard C. -- in dust ex ' _ There were 51 men working in the shop and 123 In cont on board ship Layout cutting and cement coverer's = * ee 7 t hn St MS ; %. Y ~ foe a a, te ti ts. a he t <8. gh et eve : ne 8, m~e Gaeta Ne ; whe vol 28 wash Join 1945 - VER -yo OF nee . en a Dust ranging from mhing were done at one end of shop : bestos confent 85 per cent magnesia " respirators were occasionally worn during these the other end of the shop the procedures At 10-15 asbestos to amosite 95 asbestos When asbestos coments contain large amounts fabrication of boots jackets and molds were of diatomaceous earth there is a resultant silicosis carried out A small amount of such fabrication -. hazard indicated og separate that counts below per foot was done on board ship - Material was cut with band saw in a room and the operator wore an approved In g^neral we feel dust : million partides cubic dust indicate good dust control ~- 5 by Konimeter . 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 a part of the dust given off above the table shop.. There was no exhaust ventilation in the other than for the band saw and none for the ~ pipe covering operations on board ship All floors walls and rafters of the shop were cleaned at frequent intervals with an industrial vacuum : deaner Most pipe arvering on board ship was Konimeter and nor with the impinger instrument We used the Konimeter because it is light easily portable and takes records which can be kept indefinitely As indicated in Table the dustiest operations are band saw cutting cement | mixing and installation on board ship ai second shift of coverers pipe applied in the evening during the _. The incidence asbestosis among by in Contract Ford D ; _ as determined chest ray is given Table - of There were 8 men in the shop and 160 men 4. The relation between years exposure and " working on board ship Pipe covering operations per cent asbestoais is included in Table 5 in were done two shops In the main one boots frequent turnover of and jackets for pipe valves and connections were fabricated and surplus material stored In the smaller shop the operations consisted of layout equal the and cutting of amosite water repellent amosite and fire felt There was no exhaust ventilation la either shop nor for the pipe covering operation the on board ship All asbestos cement was mixed ~ _ Due to shipyard workers and the length of time required to ray a large number of workers the number rayed may not . number of pipe coverers At Contract . Yard CX rays were examined of men had left the yard while at Navy Yard B a few pipe.coverers were not rayed At Navy Yard A- the 48 rayed out of 551 were older men working In compartment on board ship The only worker who wore an approved dust respirator was the but man who cut the two types of amosite There in the shop Sot shipyard y Some of these pipe coverers had had shipyard experience in the asbestos industry the tables was no band saw cutting of asbestos in this yard IV ANALYSES OF SETTLED . COUNTS DUST ra AND Dust a are based solely on shipyard exposure At Contract Yard C for example the Asbestos Shop estimated that about third of . their pipe ; a There are no established figures for permissible coverers had worked with asbestos before coming to the yard - movsteilnyPn-^' exhaust or safe dustiness in pipe covering operations consisted Dreessen et al 2 in their study of asbestosis in oots and jackets the asbestos textile industry suggested 5 million ip was mixed particies of total dust by impinger as a threshold no exhaust - Cement Room for that industry We should like to point out that the asbestos textile and asbestos pipe cover- a Sexible exhaust laust around the The layout tabl it.on as ing industries differ widely in their dust exposures la textile plants workers usually continue at specific jobs with fairly constant dust exposures supplied atulation supplied %. a small 3 no worken -% ; for some years whereas the pipe coverer may rotate between shop and ship and from to Large ship compartments with a wide variation Ey . in dust exposure , pipe The one case of advanced asbestosis at Contract Yard C had worked in the asbestos industry for _ 23 years 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 ray films used in the above data were first read by roentgenologists of the Medical Department of the yard and then by one of the authors W. F. Dr. W. C. Dreessen U. P. H. S. was kind enough to examine the three positive plates and he agreed on the diagnosIS Since only three workers out of the 1074 rayed the shop and 121 ing and cement In contrast to the textile worker coverer's materials differ markedly in the pipe their as- had asbestosis and each of the three had been a pipe coverer for more than 20 years it would . waar - aye wo esd, aeg ane Te neg rr bet er Ew a 8, gt ata TABLE 2 ANALYSES OF SETTLED DUST and Air Samples Jan 1940 . ; OPERATION | COUNT 200 COUNT BELOW KICHONS | ...or- anandd sat BY ------ -- glass of DUST COUNTS APPCF Total dust ASBESTOS DUZT a _ Layout and cutting Navy Yard .. Na Yarv d By . eee ContrYa arcd t C.... Contract Yard D. Others Number of counts ASBESTON opaque Duiatomaceous Serpentine ganic Range Aver- Range Aver- PIL ASBESTON Duiatomaceous Serpentine Other Others Number COUDES =| 8ee . | a . . i 16 10 30 26 6 12 6 | 24 26 10 2 3.5 8.7 6.10.21 8 12 tr | 4018 4018 12 7 1.6 6.5 0.01 5 10 tr | 26 14 15 4 17.1- 25.20.51.13 4.3012.186.6-19.525.20.513 4.3012.86.-129.5 5.220.51.13 68 68 tr | 29 21 10 5 17.1- 6.5 0.09 0.560.0 0.57.4 9 4.3012.186.6-19.5 1.1 8,76- Layout and Band saw c Sewing and Cement mix Grinding General 1001 Cutwt ithibannd g saw PT Navy Yard.. B. vice] 00000 Navy Yard | Contract Yard .. 00000 9 7 9 631 y Gee Seen Races ee at Shop aver Fe fee 2 1.0-19.215.10.10-.140.120.7 1.0-19.215.01-0.140.120.7 11.0-19.215.10.10-0.140.120.7 1.0-19.215.10.10-0.140.120.7 1.0-19.215.10.10-0.140.120.7 1.0-19.215.10.10-.140.120.7 1.0-19.215.10.10-0.140.120.7 1.0-19.215.10.10-.140.120.7 0.9 Ship aver | 8 ex 48 16 122 122 37.4 39.5 3.2 13.0 6.5 s | Nae 2 tr 10 412-318.2 100 412-318.2 10.09-12.8 4.3 12.8 Lot. : Rd Molding operations Contract Yard 48 .. gn 81.661 3. ,610, | Cont Yarr d : ac. t 95 497 497 497 RR | , 1,0 12 ; oo ' . Sewing & prep of boots & of yd 23.5 A. yoy ef 0 o 23.5 on ono 4.6. .01- 0.03 soe 1.0 Navy Yard 0.0 3.3 6.0 SeYaw rd Bi Sewn ingg as- | [ sie bestos cloth -. 2+ | 98 129 129 129 oe | 21 16 ( .. 9888 9888 98889888 11 tr 38 3 2.1- 12:14 11.4 . ofCont Yarr d a c t |95266113 952613 952669526113 1953266113 95266113 | 28~12:14 12:14 2 10.6 9.4.0.10 -6.4 2.10 0.3 .. .45-79 .62 -7.4 5Cont YardrDact 986 986 8 ax | 38 28 14 5 10.6 3,9 10.9 6.00 ~ .05 .030 -0.5 ContYarr d . ac 9t5 [ 15 8 7 | 26 32 12 - & . , Cement mYiaxridng Navy Al lece B. eee a FEEL Se cd Navy Yard PP Yard board ContrC ac . t cede - ConYt ardrD a oncbot ard . wht ship . ween PE Poet cd: - : | -100+ 84+ 16 Lf. 2 5.4-30 -0.520.2 ~ 0.7 67. -100+ 1.71.7 1.4 2.5 7 2 33.8 48.7 41.3 4.73.1 4.7-10.0 nn oo, | - | 5 19.6 40.0 0 - .02 .010 - .001 RELATIONSI RELATIONSI , Navy Yard 88 | 8 20 16 1 | Navy YYaarrdd Navy A .. eeees beens B. eee * Contract Yard C.,....--+- ContrYaa rdct D,....5--+ { | | 10 33 1215 - 9.4-100 -1.6 420 -2.6 420 | [49 * 2 0.2 24.6 1.6 3.3 2.40 4 | 0.0 14.20.34 3.9 10.9 6.00 -1.4 0.08 .02-0.3 > .01 .01 -0.6 1.|7 .8 3.8 -7.9 - .05 .02 -0.5 Navy Yard Yard Navy Navy Yard A:..seseeeeeeel Navy Yard es Navy Yard .. . .Contract Yard C. _ Contract Yard D. = : . 30 65. -250 142 0. -0.17 -0.05 15 84.4-192.0 1.36-5.21 1.1 3.7 25.3 89.0149.210.23-2.381.10.0.5-6.3 89.0149.210.23-2.3811.10.0.5-6.3 89.0149.210.23-2.3811.10.0.5-6.3 89.0149.210.23-2.381.10.0.5-6.3 15 25.315 8.0 22.111.00 -0.21.0.030 -1.0 Million particies * Note MPPCF \ of dust per cubic foot of air 14 Y. Contract Contract Y. asic3 . 7 PIPE COVERING OPERATION IOPERATIONI ~*~ ePPcrye ESE TOS STOS se tavern ----, 0.50 -0.540.230.6 -0.540.230.6 . COMPARISON OF DUSTINESS OF VARIOUS OPERATIONS IN EACH SHIPYARiDsI: ++ NAVY TARD A KATY TARD 3 |, CONTRACT YARD | CONTRACT YARD D | OPERATION Total dust | Asbestos | Total dust | Total dust Asbestos Toul dat Asbestos PPCPfi - Layout and cutting Band saw cutting 6.1 | 0.35 .15.1 | 0.12 Sewing and fabrication 4.8 | 0.03 | MPPCF .. | + MPPCP 4.2 10:23 20.5 fl.2.18 39.5 3.0 |. 73.0 6.19 4.8 0.1 .11.4 | 0.02 MPPCF Ay 10.9 | 0.63 3. - 6.0 | 0.03 . Cement mixing 31.0 0.2 84.0 [ 1.7 | 41.3 | 3.1 f 32.0 0.01 | 10.0 | 0.08 30.0 | 0.25 | 2.4 $0.01 | 0. 7 08 .8 6.0 | 0.02 26.9 1.0 32.0 2.6 7.6 0.23 ~ 12.8 6.194.3 12.86.194.3 12.8 6.194.3 12.8 Note MPPCF Million particles of dust per cubic foot of air saz . : TABLE 4 + . +.) appear that asbestos pipe coverinogf naval vessels INCIDENCE OP ASBESTOSTS AMONG PIPE COVERERS is a relatively safe occupation However it must be remembered that these men rotated among the . .: NUMAR ASBESTOSIS variousvarious operations of pipe.covering pipe.coavnedrwienreg not | SKIFTARD COVER| I- Adi continually exposed to high concentrationosf | | as KRS LATED Mini Mod- Adi asbestos dust | ] found band saw cutting and -c'ement mixing The suggestions made relative - Contract Yard 1 | Navy Yard A. Navy Yard B. .. 551 ] 750 | 174 48 662 196 0 | | O | O Contract Yard D. 168 | 168 | O | || 0 0 0 2 | and 0 to exhaust ventilation respiratory protection 0 are therefore of value in maintaining this low asbestosis 0 = ve yn er, 021 021 021 Totals .. +++ 1683 1074 021 | oy DISCUSSION The extremely low incidence of asbestosis . ay . found 0.29 per cent or 3 cases out of 1074 pipe ae TABLE 5 / coverers stands in marked contrast to the high -0.52 ASS -0.520.2 0. 0.7 3 -1.7 1.7 -4.7 3.1 | 1.4 2.5 4 4.7 15704.0 ) .001 - .02 .010 - 3f -1.6 470. 2.6 pee mq _ 8 -1.4 0.081 .02-0.3 -2% - .01 .010 -0.6 2 1.714 13.8-7.9 13.8-7.9 209 - .05 .02 -0.5 283 28 joz ) joz -0.05 1.1 .8 -3.7 0.030 0.030 -6.8 -1.0 a x ; 3 RELATIONSHIP Between LengTE OF EXPOSURE AND dust concentration found in several of the pipe INCIDENCE OF ASBESTOSTS 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 SKOPYARD cubic feet for cement mixing from 31.0 to 84.0 and Navy Navy Yard A 7 Exposed Affected Percentage 0-2 | 2-5 5-10 | phus 13 | 0 | S 0 0 % % % % % %% [ Affected Exposed Navy Yard B 225 435 67 122 . 10 10 Percentage % % % % : 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 be changed from may one operation to another or to different jobs in the same type of operation . without loss of efficiency and according to the ( Exposed | Contract Yard C Affected Percentage 0 105 15 17 % % 0 001 001 001 %| % ; ; demands of ship construction It is therefore apparent that a pipe coverer's environment may change every few days or few weeks at the most with a constant ductuation in the dust concentra- Exposed | | 9 . 26 118 $ Afe Yardc D (t Afe ectd ed 0 0 2 22 ( PercentPearcgenetage % % ! tion which he breathes Therefore the figures given in 3 for shop given in shop Table for give average average and and sshihp ip average cannot give a composite picture of the asbestos 16 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY sol 28 no- Rear dust that a worker may breathe over a period of years Itis further apparent that to obtain such . a picture daily dust counts at each specific job in each ship compartment and in the shop together | with the time spent each job would have to v among these workers would have been considerably syes greater In view of the varied character of the- environmental dust exposure in the pipe covering Bee industry on naval vessels it is manifestly impossible to set a threshold 4+. re compiled be 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 ~: grinding remain The operations industries will usually widely and where a worker specific job some a for years at conclusions drawn from other asbestos : such as textiles cannot be applied , _ A further factor maintaining a low incidence' 2. of band saw cutting , os.:. of asbestosis is that in band saw cutting grinding and cement mixing only one or two men are in- volved and the workis usually done at infrequent cement mixing and installation board ship = should be equipped with exhaust ventilation to keep the total concentration low such as several times a week intervals covepers Finally pipe coverers also apply glass wool rock wool magnesia and other types of non- of covering work this seems an asbestos insulation all of which decreases the amount of exposure to asbestos dust It h^d- the of asbestosis had likely that the pipe coverers studied ", worked steadily any of the above operations where the amount of asbestos dust in the was 3. Theincidence of asbestosis among pipe in the shipsty udiaed rwasdls ow 0.29 per cent or 3 cases out of 1074. In view of the nature - :- shipyard pipe lowincidence is surprisingany ot . 4. Since each of 3 cases fae workeadt asbestos pipe covering in shipyarcis for - more than years it may be concluded that such : cooensistently high the incihdobe.nce of asbestosis pipe covering nota+ dangerousoccupation veins te Nl , xe yo ons : wll ~ " Silicosis FAKTY Ships and United )LANZAA. -.: ~ and asbestosis Oxford 3 ioUnwiversity Press New York New York } 1938 C aircraft of the : States Fleet 2nd War Edition 1944. Pub- DREISSEN 2 W. C. in the asbestos al study of asbestosia tertileindustry Bull No. 1 Department Service Treasury 241 .Public Health ' _* 1938 aimed! ote U. S. Kahed by Ships and Aircraft 1265 York Broadway New New York