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FILE NAME State of the Art Literature SAL DATE 1944 June DOC SAL039 DOCUMENT DESCRIPTION Trade Journal Article - Dust as an Industrial Health Hazard PUBLIC LIBRARY eres, . Zz LAL oe Oo ee AIR CONDITIONING INDUSTRIAL AND IITUTIONAL pT e O REFRIGERATION PIPING HEATING VENTILATION ey was - - tate Pa a ne: beanie na teti PLAINTIFF'S hehe bad PLAINTIFF'S PLAINTIFF'S EXRICT EXRICT EXRICT ane ld Anta Sh TIP UNITED UNITED STATES OF ASIKINILA $ SEWENDRED SEWENDRED DOLLARS ISSUE DATE Umass ewe KR AND HERITA HERITHEA RITA STARTENERSTIARENRI STARTENERI 1946 nd } x OS aop at Settas ee ng 4 Sf SERS: > po al ESS Heating and Steam Genera tion with Coal is the subject of this month's Blueprint of Post Realities page 65 ry. A MONTHIT HEATING 922B , MAGAZINE FOR EXGINEERI VENTILATING | AND CONTRACTORS CONCERTED WITH . eg COMMERCIAL INDUSTRIAL AND INSTITUTIONAL AIR CONDITIONING RINGCIATION PIPING KEATING VENTILATION ! Publisher INDUSTRIAL PRESS CONTENTS FOR JUNE 1944 President ROBERT B. LUCHARS President and Treasurer EDGAR EDGAR A. BECKER VOLUME 41 NUMBER O Collecting System i Dust Benjamin Malin Gunstock in Plant .......0.0....00-..00005. 51 Secretory ERIK OBERG Editorial Staff EditorEditor Editor CLIFFORD STROCK Associate Editor N. N. WOLPERT Jolishing Grinding Wheel Quality Improved by Controlled Mie 55 1. C. Baker Dey le Dust as an Industrial Health Hazard .................. vee n.. 57 W. Hutchinson f ea \ Ventilation for Welding Booths _.. en aes | A 62 A : M. Riequist A . Ventilation Me i Ventilation for Radium Diat Storage ...n.0.....0.. . ec eee e eee tocceee ccc Lecuetececeveresccge Off Again On Again .......... cece cee sees XX John J. Woolfenden ! Blueprint of Post Realities for Heating and Jolishing ( Information Information Steam Generation .ocscccccccscccsceccccccccccsccccnecscccencece 65 Irwin R. Hofman VENTILATINiGs HEATING AND Heating is Some Notes on Radiant Heating .............- oc eeecccceeseccas . 81 W. Reynolds ; published monthly Lofayette Industrial cc : Weather Observers Have Difficulties ... ccccecceese seeceese 81 sub- New York 13. N. Y. Yearly scription in the United States Central Plant Heats 45 F. N. Bollingrworth Buildings 0. cece ......... ces cecee cee c ss cece 82 Spain South America Mexico and Canada 2.00 in all other coun- Entered 3.00 copies cents Entered Single as second 30 class matter April 18. 1925. at the Post Office New York N. Y. under the act of Building Brazil ...c.... cece cee en eee e sec eneseesterasccacereccccce, Washington News ........0--.-cccecccceccecs se cccsecceece secscoce Loving F. Ovamen | 84 86 News of the Month ............06. sect seeecusevestcseerecs . rreeee BrBirieeff RevRieewvsiews ........ 88 90 March 3 1879 News of Equipment and Materials .............0-. on a 92 Degree for April 1944 Advertising Representatives Eastern Representatives With the Manufacturers ea eeee en a Reference Data 271-272 ...........0. eeeeee Sore etenrcecee se seeeee + 104104 104 DWIGHT COOK HARRY J. TWINE 148 Lafayette Street New York 13 N. Y. Personals and Personnel ...,... ecw decreases tees ceeos acc ceenecce Getting Personal ...... eae c cece wen eene Oo eee meee ee cee ee sees coe -. Army E Awards 2.6... cece secs cee e een ececeeccees eer ecacee New Catalogs ...... SR 107 110 110 111 Western Representative Industrial Degree for April 1944 2.0.8, 113 2 GEORGE G. TURNER Coming Events CS ...... 113 228 North La Salle Street Chicago I. III Copyright 1944. by The Industrial Press | ~ : i | MEMBER Audit Bureau of Circulation Associated Business Papers : 2: | CP Process Starting - ment with MONTH'S NEXT MONTH'S is a subject that reaches our July issue Harry D. ISSUE out into many Industries Cowin of Albert Kaba Associ unt Architects & Engineers Inc. will present the first of A xerica n articles on design and layout of process piping in- Se VIS tee verre ABSORB CONDITIONING NOISES dreyduct dreyduct dreyduct ALL ASBESTOS ACOUSTICAL AND INSULATED DUCT co IN Bo radio studios hospitals churches theaters hotals ~ offices homes -wherever quiet working and living con re oe ditions are required this all asbestos prefabricated duct im EATD. will eliminate noise from the air conveying system oi Oeet Coreyduct is a development of the Carey Research Labora ky emaA tory and scientific Gold testing It is a natural sound ots absorber a conductor of sound and resonating It quiets fan noises and cuts down speaking tube e DEPUTYete ellects and eliminates cracking due to changes in a air pressure By effectively absorbing noises it permits . the use of smaller duct sizes with higher air velocities This also solves difficult installation problems where * , . i space is limited . r Besides its absorption of noise Careviluct has many other advantages over older and less efficient methods It is fireproof is quickly installed absence of noise in erection unavoidable in handling metals permits installation in occupied buildings such as hospitals stores banks etc conserves motals neat and compact can be painted to match walls and ceilings costs no more Iroquently less than insulated metal duct For technical details and further information send for Carryduct Manual Address Dept. 19 we EA 8 . im ae tS ae ON a ae 1 wk Ta iad THE PHILIP CAREY MFG COMPANY te Dependable Products Simco L^ CXLANDCINCINNATI 15 OHIO = a cee eura avee la Comodo the Phone Carey Compont Ltd Olize and forte il F. O. DC iddee's thereat, Coremeri Vocational ont Industrial Training Training Schools include the art of handing Cureyduct m their coursest on sheet metal work Pe pit x rt e Funk Furmutura Sture Evansville Ind e Chandals Ohio = nan i i. y. he Rear Carry & Intan Co. Icheruleu Icheruleu Cte mmwts we . em de ee . le ee +e ee : le . - ce let JUNE 1944 HEATING AND VENTILATIN Dust as an Industrial Health Hazard F. W. HUTCHINSON . Assistant Professor Professor of Muchanical Enginaaring University of California Berkeley Calif se 3 * a. A 2 a 3 th be ey try health problem arising from dust in industry is one of increasing seriousness Socially economically and legally it has become evident that immediate steps must be taken tocombat the hazard represented by wholesale industrial exposure to the pneumoconiosis dusts Pneumoconiosis in Dany of its forms is incurable Thus consideration of the problem which it represents is based largely on methods of dust reduction and removal and is therefore as much a responsibility of the engineer as it is of the physician Fortunately medical knowledge and engineering desire to furnish their employees with full protection from occupational injury they did not take the special care which is now known to be necessary Wilson states Most intentioned employers may be said to have used reasonable care in past years considering their lack of knowledgethis is now their best defense in damage suits However from now on with the spread ... available knowledge only special care will safeguard the interests of employer and workman alike Recent interest in dust diseases has built up an extensive literature theories have been confirmed rer equipment have progressed to such a point that with experimental evidence and innumerable case ' recognition of hazardous conditions and availability mae histories of individuals and of entire er of methods for correcting them will now permit a available In contrast to the widespreadgriogunposranacree ee arena complete practical and economical solution of the of ten years ago it would probably be difficult at the problem Unfortunately prejudice and fear have present time to find a worker in the dusty industries es hee surrounded the entire subject with such an aura of who has not at least heard of silicosis or an employ- 5 suspicion and distrust that neither workmen nor em- er who is unaware of the crippling damage suits he ployers have until recently been willing to acknowl- which will face him if his employees through failure Mn edge the hazard or recognize the need for preventive on his part to take the necessary preventive mea- measures In addition the slow action of the disease sures contract the disease H .et to re coupled with failure on the part of many physicians to acquaint themselves with the proper diagnostic methods has made it difficult for the worker to es- tablish his claim for compensation in the event of The cost of dust control is often far less than the cost of one damage suit Jury awards in silicosis cases of 10,000 17,000 22,500 25,000 and like sums are matters of record In the St. Louis area - and ndga The ar intain e : essor De func- Bre lung injury and equally difficult for the employer to defend himself against fraudulent claims it has been said that silicosis claims constitute one of the most widespread of legal rackets Workmen have bitterly opposed adoption of the alone there were some time ago over 2000 suits pending A Missouri mining company as another example faced claims aggregating 5,000,000 and spent 500,000 in court settlements of a few of them .isfied es CODne on ect led in ~~ heat main- exacting employment qualifications and periodical physical examinations of those exposed to dust which are essential to medical control Yet it is essential that persons having a predisposition to tuberculosis or a low nasal filtering efficiency be excluded from the dusty trades Similarly protection of the worker The purpose of this article is to review the liter- ature on the physiological effects of some of the haz- ardous industrial dusts and day criteria acceptable as a dust control systems to summarize present- basis for the design of demands that he be removed from exposure at the Silicosis es the I heat- com main- nes first indication of lung damage Employers on the other hand have adopted the point of view that most claims of silicosis are unfair and an unscrupulous attempt to take advantage of them The explanation behind an employer's unwillingness Silicosis is a disease of the lungs caused by the inhalation of dust containing free silica Some authorities believe but this fact has not been established that the inhalation of silicates is also a caus- ative factor andled operat ited by ount of as the ed aa LATING to acknowledge the hazard is not unreasonable The dust diseases are almost invariably of long duration and frequently are not discovered until many years after exposure has ceased Thus many employers are now in the difficult and alarming position of fac- ing claims for disease which is a result of exposure to conditions that existed in their plants 10 or 15 years ago at that time they were unaware of the health hazard associated with dusty atmospheres and consequently though they might have had every Incurable and Progressive The important facts about this disease are that for practical purposes it is progressive and incurable The qualification for practical purposes is necessary because recent in- vestigations suggest that uncomplicated silicosis is not progressive however the continued existence of a case of silicosis without the onset of complications is so rare that from the standpoint of social consequences the disease can in itself itself be regarded as progressive In the medical literature literature the progressive HEATING AND VENTILATING JUNE 1944 ; 57 Oe SaeedbRsabidilt Sk aiid Sane en he we Pn a ew tortpi le uhm ale Keath Ee a widely newpoint is the one which has been most Metallica and with reference to dust warned his adopted but the possible future significance of the readers to beware because it penetrates into the recent findings is promising P With reference the incurability of silicosis - windpipe away the implants consump- tion in the body He called attention to the fact recent work has also indicated the possibility of a that the death rate among Carpathian miners was solution but it is as yet too soon to hold out hope so great that a wife could often outlive six husbands One for satisfactory medical treatment promising The passage of time has done little to alleviate the tes LS method consists in the administration of thyroxene the investigators report that Thyroid therapy may possibly not only prevent the development of silicosis but may also arrest its further progress and possibly reduce to some extent the degree of fibrosis already existing The above remarks on the progressiveness and i hazard The development of pneumatic tools has led PP to a great increase in the dust concentrations at- tending the grinding polishing and cutting of stone The death rate among Barre granite cutters for example increased from 1.5 per 1,000 in the year 1890 to 19.6 per 1,000 in 1924 an increase attributable to the introduction of pneumatic equipment When one ies "@er ae f incurability of silicosis have been included because they show how very far the medical profession has yet to go to achieve a solution of the silicosis problem In terms of concrete present gain the sum total of the best that medicine can now offer is not of much value When dealing with contagious dis- realizes that a threshold concentration of 5 million particles per cubic foot is required to constitute a silicosis hazard for dust made up of 100 free silica it is then evident that there are many industrial operations today which represent health haz ards that did not exist prior to the introduction of cases such as smallpox and Spanish influenza it mechanical equipment has been possible to achieve a satisfactory treatment Many estimates have been made of the number as a first step toward the elimination of the disease of persons exposed to hazardous concentrations of itself in the case of silicosis a contagious disease the only advance of real significance which is silica dust but such estimates are usually based only on industrial exposure When account is taken of possible is an advance which must be brought about the fact that 60 of the earth's crust consists of by the application of basic engineering principles- silica the likelihood seems great that such estimates the reduction of dust concentrations at the breathing are conservative Lanza and Vane estimated that zone to a point such that a health hazard no longer the number of industrial workers exposed to the exists only in this way can silicosis be eradicated silica dust hazard is in excess of half a million in ALOEHae T ALOEHT ft 53 Si te If permitted to run its course without complication silicosis will lead to death by suffocation lungs becoming incapable of maintaining a gas trans- fer sufficient to sustain life Usually however ter- mination occurs as a result of complications such as those industries in which the processing or handling of siliceous material is of basic importance this esti- mate does not take account of the many workers exposed as a result of the industrial use of silica as a filtering agent if be ere aeee Low: ad E, ry a egOre --: Cey e te ae . Bos - la te oT it rw, cs l^'y a gresre: : , : rei ti ine as Se Pyak rae on rear bat Stee tuberculosis or heart disease a definite correlation has been established between silicosis and tubercu- losis but an explanation is as yet lacking With reference to tuberculosis a study of are grinders and polishers showed a death rate of 1,900 per 100,000 from tuberculosis as contrasted with 150 per 100,000 for the general population of the same state In this study the death rate of all workers in the dusty trades investigated was used More strik- ing figures and more significant ones were obtained from a Massachusetts investigation in which the tuberculosis death rate of 961 silicotic quarry work- ers was compared with that for the general population and found to be forty times as great Background and Extent The name silicosis is of relatively recent origin but the existence of the * health hazard associated with dusty work has been recognized by medical men for many centuries From the literature of the period we find that the Ptolemies knew of it Pliny the Eldereferred Eldereferred to In one other respect the silicosis hazard has not yet been evaluated As already mentioned there is definite relationship a losis between silicosis and tubercu- This fact leads to the probability that in any community in which there is a large number of sili- cotics there will be a decided familial tuberculosis hazard Fortunately however this danger is somewhat lessened as a result of the long incubation period which is found with silicosis the time a workman's lungs have reached the stage at which tuberculosis is most likely to set in it is more than probable that his children will have grown past the age at which the danger of their contracting the dis- ease is greatest departments typical heavy industry That silicosis is definitely related to a particular kind of occupational risk is demonstrated by the data from examinations ray of 2500 workmen from all of ; 5.8 had silicosis but 90.0 of those affected were foundry workers The great importance of the silica fi, Biraae shave a "2 the stone cutters disease and devised a crude respirator for the protection of miners Aristotle f warned Greek workmen against the inhalation dust Hippocrates three centuries before Christ noticed that his surgical knives were dulled by dust hazard is clearly indicated from the following com- parative Yule mortality figures from a 1933 publication of Hollis and 1000 for standard population all causes for ages 20-65 ee con mS -- > -*o3 workers in the lungs of stone In the 16th century Georges Agricola a mining engineer wrote De Re 1964 for silica group 967 for silica group The silica group above showed only three causes of death diabetes appendicitis digestive diseases which did not differ significantly from the general group The significance of these figures is at once apparent when it is considered that an estimated 110,000 workers in the United States have silicosis ge in some degree mrre Development of the Disease The time required for incapacitation due to silicosis has been the sub- RB ject of a great deal of attention but as yet no generally accepted conclusions have been reached Apparently the period of exposure preceding contrac- Were tion of the disease is a function of the dust concentration nature of the dust nature of the work and AD individual physical idiosyncrasies From a study of 9,800 cutters in the Ruhr it is concluded that 13 years exposure are required to show slight silicosis and 20 years to cause incapacitation This same study reveals that % of the deaths among silicoties occur from tuberculosis complications In porcelain workers silicosis develops slowly but progressively the second stage is usually not reached until after 10 years Among sandstone workers the minimal exposure has been found to be 11 years while for iron miners an exposure of 4 to 5 years may be responsible for the appearance of lung changes 4 to 8 years after the exposure has ceased In contrast to the above relatively long incubation periods are those found among workers engaged in blasting and in the manufacture of abrasive soaps in these occupations only 3 or 4 years may precede the onset of the disease Likewise an exam- ination of 175 men engaged in rock drilling showed that % were affected in less than one year There is a good reason for believing that under particularly heavy dust concentrations silicosis takes an acute form and may appear after an exposure of only a few months Not soon forgotten will be the case of the Hawk's Nest Hydro Plant on the New River Some 4000 workers mostly negroes were employed for wages of 3.00 for a hour day in a relatively short time after completion of the tunnel work 475 of them were dead and an estimated 1500 others incurably ill This case was investigated by committee in the House of Representatives before whom witnesses testified that In the tunnel 10 drills were in operation at once and you could not see ten feet ahead of you even with the headlight of the donkey engine Workmen were so thoroughly covered with a silica dust that you could not tell a white man from a colored man 15 feet away It was this case that a senator from West Virginia de- scribed as the most horrible industrial disaster in salt the history of the world It was of this case that pen!ir 2 Representative Marcantonio of New York charged that 169 workers had been buried unidentified be- _ ause the undertaker had lost his records On the basis of all evidence which has yet been brought for- mary h ward it would seem to the impartial investigator T i the Hawk's Nest Tunnel should remain a tragic ladies reminder to the engineer of the need for considerHEATING AND VENTILATING JUNE 1944 nticde ation of human values in the solution of engineering problems The above case is only one of a number of similar that but less sensational cases which have shown there is a real possibility of contracting an acute form of silicosis if work is in an atmosphere having an extremely high concentration of siliceous dust Experimentally the possibility of acute silicosis has been demonstrated by laboratory tests on animals for exposures of eight hours a day to concentrations of 200 million particles per cubic foot or more it has been shown that the last stage of silicosis may be , expected in a relatively short time Size of Hazardous Dust The importance of par- ticle size in determining the hazard associated with dusts has received a great deal of attention Par- ticles 25 to 30 microns in size will usually settle out rapidly and are therefore not likely to be breathed in quantities sufficient to constitute a hazard How- ever particles of this magnitude such as pollen of the Giant Ragweed or wood dust in carpenter shops may be responsible for hay fever or for various types of asthma In general particles greater than 10 mi- crons are caught in the trachea large bronchi and mucous membrane Particles around 5 microns go to the respiratory tract but few of them reach the alveoli where the I micron particles are most numer- ous Policard made a detailed examination of the lungs of two silicotic miners and found that 50 of the particles were less than 4 micron and 75 less than I micron his findings should be used with care however because it is very probable that the dust distribution in the lungs is a function of the distribution of particle size in the inhaled dust Poli- card's findings may be applicable only for the conditions under which the men whose lungs he examined had worked The smaller particles are obviously the most dangerous since on a weight basis they offer a much larger surface than do the larger ones For this reason dust counts are of more value in evaluating the hazard associated with a dusty environment than are gravimetric dust de- terminations The dust particles that are most effective in the causation of silicosis are of a magnitude so small that they are not perceptible to the human eye A micron is 1/1000 of a millimeter or about 25,000 of an inch As has been shown the particles most important in silicosis are in the neighborhood of .5 micron or 50,000 of an inch represents a dimension of the same order of magnitude as the wave length of that form of radiant energy which we recognize as light If one cubic inch of quartz were broken into cubes .5 micron on a ticles would be formed to create side enough par- a silicosis hazard in a 250,000 cubic foot space The determination of mean dust sizes was the purpose of a series of comprehensive studies con- ducted by the U. Public Health Service examina- 18,000 tion of outdoor dust particles showed the median size to be .5 nearly all were less 59 eg he ; or Ue oe b Dal han Takia Saiqm. . ad bhi ie ae te -fi = ary ooead a-8. ew.. at tifcs Mast. sf a Se lar; SARSS. yeeyi Zio 2. . A6p findings der microns which decreases comprises comprises 90 % the from 1/5 1/25 that total the found number greater particles emphasize than greater microns microns These findings di- emphasize necessity taking dust samples from the contaminated contaminated air utilizing rectly from any other kind settlement sample rafter settlement sample distri- Practically characteristics tions dust vary composition dust retention retention composition individual The characteristics characteristics of some latter factor which hope from the standpoint standpoint standpoint preventive preventive preventivoe ffers all standpoint that known of the retaining attributable to the work of one normal magnesium retained during magnesium % oxide varied retained during about breathin . breath coc rest varied little Above 10 the men centration mg but the concentration concentration retentio retentio droppe changed little the retention rapidly Cropp. 10 approache approache relationship relation between dust relation silicosis has concentration concentration been studied ang th. vestigators no general empirical remlataionnsyhip in Many ip vestigators yet been established established commonly proposed proposed Drinker recommends accep y..' proposed million million particles recommends the per cubic foot pure a, the Physiological foot responsible complica- is to limit the total dust count the product product the dust concentration concentration by concentration the such percentage silica be less than 5,000,000 cubic by the gives 100,000,000 particles the role minimal concentration lung siliceous dusts . as the condition knowD from silicosis silicosis Why the inhalation silica- keown silica possesses possesses ability to silicg. bearing dusts condition has bring about investigation been subject of to much theories of silicosis silicosis at of present excluding consiedxecrlaubldeing considerable controversy controversy complica- at effect a oe ee F aee Pera aes. Ere a *) T~e, a oy. a wy wtLade. prmtesYet aPad b>.. eee! Vows Tee bd ~ ewim 17.8 rr Sen enceAW,Var. har Mar . aril i p=)rare MEL de es e Tobey Tune. ~ a -: chemical chemical composition composition narrowness nar ownes nar ownes narrowness passages the nasal seemingly fixa- vortex formation and re- silicosis silicosis As a As result of experiments Carlton Oxide oxide calcium Brown gives gives carbonate relationships between dust following relationships between between tention tention and other re. : Per J. Per Retention Retention inversely below per Respiration Respiration rate increase above per minute minute increase followed by minute is changes changes apparently retention followed no changes in per per volume 2. Minute volume from increase respiration respiration ably ably results minute volume . rate rate Retention Per Per Volume per respiration }. 2. by Vital capacity 2. 2. Relative The 3. The investigator The same found that the percentage of 60 formation scale this this surface its exchange exchange medium medium scale becomes effetctiverness aefnfectivesness fseumrciently of of an heavy impossible impossible impossible secure enough heat heat accomplish purpose which accomplish purpose exchanger was was the lung sur- of through through installed similarly transferred from the the air oxygen the The scar tissue tissue re- re- duces duces the effective transfer area eventually the the transfer area purpose death from lung unable unable accomplish fe. . suffocation sufocation suffocation the purpose purpose eventually the result its suffocation is the result. Purpose deatfhrom . 43 magnesia magnesia frequently present and Oxide particles appears appears frequently frequently translucent fibers dark particles 1s fibers fibers are than such length fineness that length and yard cloth weighing less than been oz lung condition condition from them inhalation inhalation OZ. of dust resulting from inhalation resembles 8 silicosis silicosis ma knoi wnnknown as asbestosis but differs of to enhanced enhanced clinical aspects but average rate development development employment industrial industrial industrial conditions the employment to fatal cases half employment which usual only about half which fatal fatal conditions the HEATING AND averare cases JUNE JUNE 1944 VENTILATING VENTILATING HEATING AND wa:ch is usual JUNE? 1944, HEATING AND VENTILATING  ir alicosis It is estimated that there are in the United States approximately 10,000 men exposed to dus hazard as a result of work in the _ abertos cloth and similar industries As iinssutlrauteinogf e silicosis exposure estimates this figure does ute into account the number of not persons exposed as result of employment in the process industries where asbestos finds use under various trade filter aid In names one respect asbestosis is less dead- ty than silicosis is there is seemingly a lower susceptibility to the supervention of pulmonary tu- berculosis The danger of contracting the disease is for pure : apparently not influenced by either age or sex Like silicosis it is incurable and progressive a case is re- t for duru te ported of a patient who was exposed to asbestos dust suggests for one year and whose sputum showed the usts which is of asbestosis bodies fourteen years later presence widely value Very few data are available on the relation of dust such on by the concentration to the incidence of the disease No minimal safe concentrations have ; this rule and information is yet been set up ot seant as to the conditions in those as the plants where a hazard is known to exist It has Usts been determined however that the asbestos dust on known en- countered in fabricating plants is free of silica 1 of silica- when air floated at the breathing level and that the ability to subject of danger of the dust increases as the quality or length the fibers increases sis are at ntroversy , complica the a cale In are sepaeposit of ess as an ufficiently ansfer of which the is a surfrom the issue re- ually the ath from in the presents composi ly 43 nhs, : of iron 0in6e: particles of such Anhatibate than 8 m halation Y_ es Yes a. de -Age oat icnt del usual A Miscellaneous Siliceous Dusts Many siliceous dusts other than quartz and asbestos have been carefully investigated Talc siliate containing 62 silica been shown to be responsible for a form of pneumoconiosis when in- baled in large quantities One group of investigators report that 50 of the tale workers whom they ex- amined were affected and about % had tubercuiosis The same report shows that tale % tremolite is much more dangerous ctohnatanintianlgc containing 40 tremolite but an explanation is lacking The action of cement on the lungs is not known German investigators definitely that it say only an inert deposit in the produces lungs but American re- ports show that the frequency of disability from respiratory diseases in cement plants is about double that found among employees in dusty manu- facturing plants absence from work was also twice as frequent Yet animal experiments show that ce- ment like limestone and gypsum produces an ad- sorptive reaction the dust disappears from the peritoneal cavity without the production of scar tissue Slate % quartz in concentrations of 700 million particles per cubic foot produces a fibrosis and pneumoconiosis but few cases have been known to progress seriously On the other hand there is dusts reason for believing that clay and slate are responsible for a high incidence of tuberculosis Italian investigators have studied the dust hazard I cotton spinning mills and report that the silicosis hazard is apparently negligible Mineralogic analy- LATING 4 HEATING AND VENTILATING JUNE 1944 interesting sis of such dusts brought brought to light the that their composition is similar to that of the fsaocilt in which the cotton was grown Siliceous Dusts Apparently there is a great difference of opinion as to whether or not siliceous dusts are harmful either to normal or tubercular persons The data are so scant that a review of the literature must consist essentially of a catalogue of the few and scat- tered investigations that have been made of particu- lar dusts General conclusions can not be drawn and an extension of available data to dusts of even the same mineral family is hazardous German investigators have studied a number of different carbon dusts and rate them in the order of hazard which they represent lignite coal graphite charcoal soot A statistical study of the health hazard in American company which manufactures aratifliacrigael abrasives led to the conclusion that persons who have had pulmonary tuberculosis should not be allowed to work where they will be exposed to dust from abrasives The dust in this particular plant was aluminum oxide combined with silicon carbide and the incidence to tuberculosis was 1 1/2 times as great in the dusty departments as in the dusty In this connection it is interesting to note that other investigators had previously reported aluminum oxide as not being a factor in the production of silicosis thus a distinction must be drawn between the forming ability of a particular dust and its danger through increased susceptibility to pulmonary tuberculosis This leads to the conclusion that the claim is unwarranted that a dust is not harmful merely because its reaction on lung tissue is inert The U. S. Public Health Service has grouped dusts siliceous as well as siliceous in three classi^-- cations 1. Those causing an inert reaction the amount of dust in the peritoneal cavity remaining approximately constant soapstone carborundum jewel- er's rouge anthracite coal bituminous coal and precipitator ash 2. Those causing a proliferative reaction nod- ules continuing to increase in size and flint quartz chat 3. Those causing an absorptive reaction disappears from the peritoneal cavity but tissue is not formed calcite dust scar limestone ed calcium carbonate gypsum and cemeprnetcipitat- A similar list of dusts has been Haynes who carried prepared by on a long series of animal ex- periments He arranges them in order of follows precipitated silica Bint slate toxicity as hydroxide precipitated chalk magnesium carbonate carborun- dum calspar emery colloidal coal in massive amounts forming togAeltlheorf wtihteh respiratory disorders discussed above inhalation of many others which are caused by the der the dusts are grouped un- one broad term Pneumoconiosis - 61 re os, . ALPHABETICAL INDEX OF ADVERTISERS A yw Acme Industries |. vee eens f Air Conditioning Engineering Co. ie Maze Corporation 0.0.00. 43 116 40 General General G Controls Co. Electric Co. 107 ............ + ..... 1... Penn Electric Switch Co. Porter H. W. & Co. Inc. Tees Regulator Powers Co. 1... vere s-|. qt ]. sit 1 f b jane Airtemp Div Chrysler Corp. .... 4 Co. Airtherm Mfg 0 105 Alco Valve Co. Corporation .1-24 .11-24 Allen Corporation e toe e cec eee ns 13 American Air Filter Co. Inc. 2... 27 American Blower Corp. oo soseesees American District Steam Co. .... 119 . H Hays Corp. ve. Henry Valve Co. ............... Holcomb & Hoke Mfg Co. ...... Howell Electric Motors Co 117 39 Propellair Inc. ss... otters R Reznor Manufacturing Co. . Ric Co. ... sees ;4) American Pumps Inc. seen Inside Back Cover re gy [ P American Rolling 10 Mill Co. ...... Armstrong Machine Works ...... 10 Automatic Products Co. ......... 10 . B f. Badger Mfg & Sales Co. ........ . Electric Baldor Co. .... 10 5 I Ventilating Ilg Electric Ventilating Co. ...... bd Illinois Engineering Co. Inc. id Illinois Testing Laboratories Inc. 114 Iron Fireman Mfg . Co. ......00., 101 . : S Sall Mountain Co. ........0..00 Sarcotherm Controls Inc. Inc. , Inc. ... Smith Smith H. B. Co. Inc. ... tceees Somers H. J. Inc. Cott te ceeeeeee Star Electric Motor Co. ....... +. ay Colman Co. .........,.... ' Bell & Gossett Co. ee... eee... t Bethlehem Steel Co. trtsesessees ))) Breidert G. C. Co. ... eeeees 38 J 35 971 'Johnson Johnson Fan & Blower Corp. .... 36 Service Co. .Back .Back Cover , Superior Sheet Steel Co. teeveees T Brooks Equipment Co. ......_... 114 | Bryant Heater Co. see eeseeeccees 32 t Bufalo Bolt Co. ... 7 \Buffalo Forge Co. ......0.000. 45 A. M. Byers Co. lt ............ 7 7 ~ el Ls i | Carey Philip Mfg Co. ..... sreee 34 Carrier Corporation ... 33 a kf 4: rt ett Cash A. W. Valve Mfg Corp. Chrysler Corporation ........... Classified Advertising seesesesses Continental Steel Corp. ......... Crane Co. eee. ....... eee. 12 q 116 31 Crown Iron Works Co. .......... 115 it:lf Curtis . F Refrigerating Refrigerating Mch Div of 48 a K Kewanee Corp. Kewanee Korfund BoiBloiler er Co. Inc. ........... eee, 8 119 L : Ladish Drop Forge Co. .......... 29 Leland Electric Co. ....0.0...,.. 23 Link Co. eee, 16 M Co. Marley Inc. eee Mario Coil Co. ol, 41 Mercoid Corp. Corp. eee eee McCord Radiator & Mfg Co. 117 ; Taylor Forge & Pipe Works Thrush H. A. & Co. oo... Todd Shipyards Corp. Combus tion Equipment Div ...2...., Trane Co. ... Trerice H. O. Co. Lek eee eae Turcs Inc. ......,.. erences: Tuttle & Bailey Inc. 6... . . U U. S. Machine Corp. ............ United States Air Conditioning Corp. esse esses eee eeecseeeeees United States Radiator Corp. .... 3 Ree ir ie See - eeaatiF s mace sta ft merece eee: 5 Ree 3 Pa? ~ We ae 4 r thi 4 |; dit wih 3 D Detroit Lubricator Co. ......2... Detroit Stamping Co. theesevceee Dravo Corporation .............. Dunbam C. A. Co. 0.0.2.0... 6 119 93 103 ti: .* unt ; E i} Economy Pumps Inc. . wee seeeseee } F Electric Auto Co. ........... 112 ary Elgo Shutter & Manufacturing Co. ^'Ellsworth Pipe & Supply Co. 17 .... oa Emerson Electric Manufacturing . Co. wee, rr a ! nea uf . F he Freeman Stoker Div Illinois Iron wER OS & Bolt Co. 111 ho 120 McDonnell & Miller ...... bes eeee 95 Minneapolis Regulator Co. wwe ..... Inside Front Cover Modine Manufacturing Co. ....., 42 Mueller Brass Co. 2.0.0... 26 _ Loo. N N Nash Engineering Co. Nelson Herman Corp. 50 .18-19 .18-19 o Corning Fiberglas Corp 99 P Pacific Steel Boilers |, ......... Patterson Co. Inc. ....... Peerless Pump Div Food Machin ery Corp. el, 5 * 110 W : AeGos Wagner Electric Co. Faron & TELS Tirereeeee, & Want Advertisements .........., is ae: Webster & Co. a Warren .... Bic ant. Weeks B. H. 3 CT tte te tec eee cans SSS Westinghouse Electric & Manu- 4 rod E June Seis AT facturing Co. 2 ... terse sees A White Rodgers Electric Co. .....'ba Whitlock Manufacturing Co. .... Spaetae Wing L. J. Mfg Co. .... .... ecees 1g Worthington Pump & Machinery ery Corp. ... beveceaeeees see wise . 3 . 45a ns Ly eae Y ans :t 2s i 52 Ss aed Y lay, =o g Waring Co. .109-114215 .109-114215 sakew & .109-1 4215 York Heat Div Shipley Isc Young Radiator Co. ASPs . 2... . 1a ~ Papi Agreement Agreement appeared faca SEES in preceding : Company Cleveland Crankshaft Every 49 seconds another bomb bomb to 2100 F. leaves Tacco casing with tail end heated unit for spinning Tocco heat treating mS mode by The Ohio =o Exs airplane propeller ends to Ein 115 seconds Increase out- bill chucks 600 per cent In ing to hundreds of manufac cal equipment air is circulated throughout the cabinet This air must obviously be clean as a whistle Stop Air Filters inside the intake louvres that way see inset make it that can be easily removed when clogged with dirt accumulations and Dust replaced with a new clean in a few minutes Tocco is but one interesting example of how Stops can be ponts faster production lower Saves Possible Expense designed and engineered into ma- , md improved products insides consist of expensive machinery A genera ator is its heart /a-ssure proper NAVY * operating temperature for the enclosed electri- Stops are one of the contributing factors to Tocco's remarkably low maintenance costs made possible by careful design and engineering of the complete unit All users of machinery equipped with Stops have the advantages of a change standard size filter chines where dust must be control led For further information on this type of application write Owens- Corning Fiberglas Corporation 1912 Nicholas Build- ing Toledo 1 Ohio Fiberglas Canada Ltd. Oshawa Ontario e Re DUSTOP DUSTOP DUSTOP T M. Reg DUSTOP Ps Of AIR FILTERS 99