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^ * m \ ' \ ' * *^ U. S. TREASURY DEPAttTMEtit ruaLIC HEALTH skbyics J Public Health BolieBn No. 217 . (0 April M33 THE DETESSHNATION AND CONTEOI 0? INDUSTRIAL DUST Br J. J. ItLOOMFIKLD KapJlary Kacinnr U. S. PphJbe llntlllp WrVo* J. M. DALLAVALLE JkmMaat Suin'? Kaci<Mr U, S- Pabl'rc llm>Ufc Hr 'C h-' *-;-- rti"* r n l ;' riusrAUKO nv direction or the surgeon general ui OO tm ub It) ika UNITED states government hunting office wamiiincton t ms | BB 0019963 | W^tblnBlwA* I** Trk U THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM. IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES* INC. SfT5?I355C555^B^? 3??HS^5 .Upijjvaw 2557 Tirs DETERMINATION AND CONTROL OF INDUSTRIAL DUST PREFACE Tti recent- y?-jrs, the subject of the health of workers in dusty trades li.fi lavn receiving considerable attention from students of industrial li-.gifnc and others hitcrested in the various phases of this problem. Wlini one realizes that the workmen employed in the dusty trades nunpriso the largest group exposed to any one industrial hazard, it is quite apparent that the imjiorianec of tliis problem has not been overestimated. Furthermore, it is now well established Hint exposure to certain kinds of dusts, such as those containing considerable uiuntiiits of quartz, has increased the morbidity and mortality rate from respiratory diseases; while metallic dusts, such as lead and its enmfmund*, have been associated with general systemic poisoning of workers. ` Jn view of the fact tint certain kinds of dusts have been known to produce definitn damage to Uie workers exposed to them, it is obvious that a knowledge of the properties of a given dust, which determines its rapacity to produce injurious effects, is essential. Experience has shnvn that these properties arc the composition of lire dust, the quantity suspended in the industrial atmosphere, and its particle size. In order to study all these factors involved in the industrial dust problem, it is necessary to conduct careful investigations. Such at mites in industry* serve o three-fold purjioso. First, they cnablo one lo evaluate the extent of the hazard; this is accomplished by obtaining occupational dust exposures'," which disclose the dusl-creatiiig tasks. Second,-if cliuical studies arc also made, dust counts may indicate the !M>mii:i*ihlc amount of dust wliicb may bo breathed with impunity. Third, dust determinations are used in an attempt to control llio liazanl; this is effected by testing the efficiency of such devices which have been developed for tliis purpose. The purport of the present bulletin is to present the methods and _ h.-t rumenU used in conducting dust studies in industry, llio manner % *-f interpreting tho results of such studies, and their practical applica- linn to industrial problems, especially those phases dealing with tho CL) ri'. u. 'o V "" o . . T. . P.?p?p SSTMES- 'NC. >10 NO*T CROECMOERII [T S FILES and CANNOT be AUTHENTir BY PPG INDUSTRIES, INC UTMENT,C i I 245S 2 control of the dust luixiird. Tim nmterinl in this bulletin is bast'd largely on (he pmr llnd r.'cjmrirnw gained by the nut hors in engineering studies of the dust problem in numerous industries in tl*o United Slates. It is (heir sincere hope Hint this little voluiuo will servo as a guide to engineers, chemists, and others interested in those studies designed to niinuiinx tlio hazard associated wilh the inlmlation of certain types of dusts. J.J.B. 3. M. D. O CO --r~. c.j--jJi \ ) *J o \h, o f-- h- oo | B8 0019965 1 THIS DOCUMENT WAS NOTA RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. * _ inTliw bulletin is based zhonuttiorM in engiiuvrtmr industries in (tic United tie volume will serve a< n tereslrd in those studies d with the hdudatinn of J. J. Tl. J. M. 1). i x. rmxniiXAKY srcrs: the sanitary and occupational SURVEY* 111 llm study 6f industrial health problems it is necessary to accumu late certain fundni'icnlal data winch may serve in the interpretation of theso problems on a scientific basis. Ono outstanding cxnmplo of such studies lias been the investigations conducted in connection witii the influence of the inhalation of atmospheric dust on the health, of workers in industrial environments. In all such Investigations there arc certain preliminary stejw of fundamental importance which must be undertaken in order to serve us a guide in the more detailed studies to follow. liooghly, those preliminary stcj may be divided into two parts, (1) the sanitary survey, und (2) the occupational analysis. SI ^ tue sanitary sukvet The sanitary survey of tlie workroom environment may be likened to the inventory of materials and stock which a business establish ment usually undergoes annually. Tlie sanitary survey luay well be regarded as a listing of the facilities afforded the workers while in tlie industrial environment. When one realizes that one-third of tho workers day ir. spent in this enviroiunent, one clearly sees the neces sity for a study of all those factors which bear on tlie health of the industrial worker. In the course of certain studies conducted in munition plants during the last war, Winslow-and Greenburg devised an inspection form which proved very useful in their studies of factory workrooms. (1) Tins form lias been utilized in numerous investigations in industrial estab lishments throughout the- United States, and it has been found in nearly all instances tliat the filling-out of this form* has proved a valuables guide and starting point in the study of the workroom environment Under items 1 to 4 provision has been mndo to record general sanitary nml hygienic data concerned chiefly with tlie workrooms. Under numbers 5 to 11 are noLcd those industrial hazards created more particularly by sjievial processes and materials 'teed hi these processes. Item 12 of the inspection card deals mainly ^ wit It tho occupational analysis and will be discussed in more detail in : the wetion of this chapter denling with this subject. .5 .\ > W. O ' * IUvSktU to HiUa-attaa AUR.*, IUU. C3) I BB 0019966 | t iS vJ 1 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 2460 4 No______ *,5TyjVof _ Mlttoo-- iiO0004 ****' X Yriititiiintt--Xaaml-- HKLJJ rWK>Tl(IATIONg ----Pt^1 mljiMmiii.w..i.H--w---n- -n---M---w-- ___1>L3oMa..ulnft...^-- .. Ami'S*. , CPcW4ntWtatLa._..., lhy* im WfL.................. JluvtHltty........ *aH** *** Remarks: 1. ISunicite--N<Unl..u.._,, Oeamltopt^riNi . WMiW *!)! it! iUlirtr,,........................... iniiiuii-TriM ond m,,ui_u .`Inv at sljtr....... ...... _..... 4. Gescral cc3*!4i*jO--Uf!u cno*____ CwpWorttrrfea.. .* -- i .............r;-s pmicttioaTM..,TM. CI o|TjiC ..._...__._._._.._i_ i --__ Ws-luts ftrilHltf______________________ Jlalitr; t-iilllH!*___________________________,, Toi>i fteUiuo--'Type iad no. Veeli Mule_______._ k. FutrPiyrihny`tntinnwtgaiUlws._.a..l...r...,,.... C. F-natt Mi! l. Duti.. ______ t. S;rine j><v:>ni_ IQ1. >|v -ute.t.o..i.m..i or t UIL.. KKupnW;`!yiinmf_i_te. Mniimom.rfiitiuwe from vir '*il!i*w** i,".I.--..n.--.i...... Cmulltim. , , ,,,,-Oeiwrul itnpmHoa. __Sweeping *rvIC_______________ Cooduton_____AIDpie Itaytbut Night shut Umih J:r l!U4* bl rtniad prod* act Km* pierce skairii Taskilled SkCkU rn. n-ukd Method ct tnyaut Seals U>1 htla r.*piirir elite byteauk* TTa*> anli Reft lnod Ean rms period M rM FM F Mr . .*.< * I*-*:.i\i : ii*** ' T. rA ' - Jj ' .j ;: '.3 \ li ;5 l* IM i,i .5 CJ> it |i t .1 i! i i !1 ------- iUJI1 _^TTTT *** -- -- ... --* -- Ttit&L -- "** A,, H ill "*E Catar AbK<oCb9ttrUrim.' mJ labor tomnyor. In practice, the sanitary survey`consists in carefully filling out the insjKtction form and jotliug down any additional notes on items which may not be provided for in tlie survey form. Under certain condi tions, such as may exist in a coal mine, or a cement mill, somo of tlie items listed in tho card nmy obviously be omitted. After filling out - a surv ey card for each workroom in the entire plant a detailed analysis & of the data contained- in the cards is then in order. It is such .an 1 analysis that enables one to form a picture of the hygienic conditions in each of tho workrooms studied and in tho plant as a wliolo. Ono or two illustrations of an analysis of data, obtained in a sanitary survey of a plant will suflice to clarify the technic involved in such.RO- ___ T--B 00^9^L1 |C document was not a record-of 3 .NDUSTrIeS, INC. DID NOT COME FROM 5 FILES AND CANNOT BE AUTHENTICATED PPG INDUSTRIES, INC. 3461 r 7>a:#. 1 Mniiinm (ms dr (Mr . -1IT-.,,M1T^ tatinre ............. C- .. . CtMOl lnyMi . Coruii'ioo_____Asnfii* - -fi iCtl r'<rji l7!~ ll.ttr*>i Zx<r ci.*o pewd i--* M lull janO*. Color carefully filling out the -ud notes on items which . Under certain condicincut mill, some of the dtled. After tilling out plmila detailed nuaUsis :n tder. Jt is such an t!e bygieitie. condition* plant as a whole, ta obtained in a .MiuiSnry hnic involved in such au s analysis. . lUiiercjiee to the survey card shows that under item 1, the size of cuch workroom is obtained and that under item 12 the work room population at full production is aUo recorded. In the rtcnmplo given below a survey of 5(1 workrooms was completed and the follow ing table illustrates how the data on space allotment was handled: TahuK l.--Ditlributioa of xnrkroomt according la per capita apace al!o/menl SqtCM ft Omt im |r catSU "SVLKliwt 1 in M b 1 (nup i . Cable Ini per capo* a* pjt !^Xli a pi ,IPMOP^ t * 3 Mi. 14 ai i.tr.wi.'jvt '****!!**!*"* 1 3 yon **t ........... ... .. XttittMr efruuiii Ui* paw N* i 13 1 * According to the Tentative Code of tlie United States Public Health Service on Yt'orkroom Sanitation, 25 square feet of floor area per capita, or 250 cubic feet of air space per capita, may be considered ns a fairly ample space allotment. In the light of tho abovo standards the data indicated in table 1 show that 3, or 6 percent, of the rooms did not fulfill the requirement for area allotment and that 4 percent of the rooms did not meet the standard for per capita cubic content. Similar analyses may be carried out for the other items listed in tlia survey fonn. ---------- Several years ago, in studying the dust liazard in a modem factory, it was considered best to conduct a sanitaiy survey of the numerous workrooms in this factory, in order to be able to locate the dusty workrooms and processes, and to plan the dust sampling schedules intelligently. As a result of such a sanitary survey numerous safety hazards were encountered in the various workrooms and m addition a lead and benzol hazard (unknown to the plant officials) were also disclosed. To recapitulate, the sanitary survey o workrooms in any plant yield* definite information concerning the presence and extent of various health hazards and often serves as a guido in establishing which hazards require further study in the form*of actual quantita tive analyses; such, for example, as the determination of hi'dropen sulphide iu the spinning room of a rayon, silk manufacturing plant using the viscose process. Unquestionably, many problems urise iu hulustiy for which there arc no simple solution*. ` Other* require coikadcmhlc c.\)>etiditurc of funds and ingenuity for their complete eradication.' On the other hand, a Kunitnry smwey of a factory will ften <li;el;ai many smalt problems which require very lit lie ex- !,litun* of money nl dlorl for (heir elimination. Tbo solution f Mich small problems may eliminate sources of ill health or uii- \^ O <2 THIS DOCUMENT was NOT A pit, irl mc-m not CO I BB 0019968 | 2462 pleasantness to the industrial worker, bo tlrnt tho worker and, iu the end, the plant management ure those to bcnclit. OCCUPATIONAL SUUVF.T A very ini|iortant part of any study of workroom environment is the wcupatiomil analysis, wl:ieh permits ono to Jeam of tho activi ties involved tuul the particular hazards associated with each occu pation. Such nn analysis also disclose* the number of persons in each occupation, which gives one an idea of the importance of each hazard from the vicw|>oint of the nuuihcrs involved. Perhaps a typical example of such m analysis will servo to portray the value of tho occupational survey. J'or tho soke of simplicity an analysis of workrooms in which only one major hazard wns found to exist* is herewith presented, namely, the occupations involved in grunitoculting plants. The table helow shows the various occupations followed in 14 typical grauite-culting plants (2). . Tnu (WnuMlw b'j pmpat.'oh of certain pmnitf-otttuip Mo jI umt-r in--1 Occopjlina NwNr at men l,0'Uiniu>lo<il vnrlfr.i__ (.'ar'b^nrJ Muna-- ------... Tmi Krii-Icr*...--.........-- nfst>. Vfw.'n^W ----,.,,r-------------r-- r 2411 91 1 T.-I--. ----- ft IVrJ '.MOW._____________----..I KlalttltsaCsrfa**.-W---rn..._............ ........j s ---- --------* m Tliero tiro several important facts to bo derived from a study f the occupations in gntnile-culting plants, such .as.in tho analysis presenteel in the nlovc table. First, tlio processes involved in granilo stone-cutting may be divided roughly into two parU/nainely, those occupations dealing with the actual cutting of tho stone and tho additionul lalior necessary for tho conduct of tho former proc esses. Examination or table 2 shows tliut under tho heading of granite cut Lera there are five general occupations^. Also by far Lite greatest number of jiersons aro engaged in tusks involving tho pro duction of dust, l'lirthennore, that 0C5 of the 702 persons creating dust arc engaged in work involving tho use of the hand pneumatic tool, a deviro well-known to 1st produrtivo of enormous quantities of dust. It is at onco obvious from such nn ntmlysis that consider able time sluiuhl he devoted to the study of tho dust exposure of granite cutlers in general and of luimi pticuiualie-tool workers in particular. The results of such a study urn presented in table 3. I BB 0019969 r..a WAS ,,'QT A RECOI PPG INDUSTRIES, INC. DID NOT COME IT'S FILES AND CANNOT BE AUTHENTU BY PPG INDUSTRIES, IN*C NT,< lea :io worker ami, in .t. om enrirunmenL u learn of the net ivi ed with cflHi norti:nbcr of persons in imjjortance of each voiveil. Perhaps a i portray the value jiplieity an analysis was found to e.vrt rnvolvml in gnmiti\-ariou* occupations 'le-ruttinf tkrj* K1 ved from study of U a* in the analysis 'recesses involved in to two parts, namely, tin;* of llio stone and ; of the former precmder tho heading of nits. Also by far the ~ka involving the pn>70*2 persons creating f the luuul pneumatic f eonniHtiis quantities jftalysis that considerthe dost exposure of malic-tool workers in mciifnl in table .1. Taulk 2.--IIu*1?mq tkf mrinus weCHjwtimx in the grnuilt.-ruXittp imtuatry nfrunliug /> their <Ih*1 rffitmere OccotaUoft Number Xmh*r fcipUMtat vaUmu Hot mint (in mltllw* *t jtntiwirti ir cul4u tunl) MiniMIMH %l*\U MUltt ,Vtne* All |tnnMaj<i|. hunl-Cwi-f--**-- - ---- , . itarinruiwx In -H-,,______________________..... ... .... Cjnrm'.s i-_.............. - ---------- (Im-Tjj flat :.:km Iniflw W^ti***^Am . - Olirruor.-- Pivtrv*'*. .n.n-1T-.r .r r T-I ( 11 mi T >..!- J-| I..1 j'-liirLMnk},* uh-l --t------ ------- ------t--- Ultl4A *********>. * i aa n 14 m M .0 w H 1U :i 91 11? 9) 4 n ' 4.3 131 4 43 4 ii 8.0 44 h 1.3 4 0 l* 10 4 4.0 103 1 . 10 4 L .301.0 MS.T IlCL 3 wxs cro M.0 Mi f U.I 4.0 U 14 11 410 43. k.q S.1 sis 1J.9 10 13 4.6 It L * As a result of a prolonged study of tho health of the workers engaged in tho various occupations of granite-cutting, it was possible to demonstrate that lhn.se persons engaged for many years in tasks 8SS(*ciated with a dust cx]xurc of lc<3 than 10 mQHon particles per enh's foot of nir'wero not suirering from silicosis or tuberculosis, tho diseases most prevalent among these granito cutlers. It was also possible to demonstrate tlmt among these granite cutters, tho incidence of silicosis and tuberculosis, all other factors being equal, was directly proportional to the degree of dust exposure. Tho im|K>rtnnee of an occupational analysis from the viewpoint of determining the extent of an occupation:!! hazard is at once obvious. Such an analysis is of still greater importance in tho subsequent steps necessary for ino elimination of a condition known to he inimical to health. Unless ono knows definitely which occupations in a workroom, containing many diverse processes and activities, aro associated with unhealthful conditions, it is impossible to map out a constructive and effective program of prevention. Wc have just seen tliat in tlie case of the granite-cutting study the problem resolves itself to keeping the dust contenl.of the workroom nir below the lore! of that associated with those occupations found to be free from silicas* and tuberculosis, oven after many years of industrial exposure; uaindy, those occupations exposed to less than 10 million particles of dust per cubic foot of air. The same technic may bo applied to oilier industrial problems, which on first examination seem more diJjjetdLof solution than the ease just cited. Perhaps another sing,o illustration will demonstrate the value of the occupational analysis as a guide in the elimination of industriid health hazards. Studies of industrial morbidity made hv the United States Public Health Service indicato that the greatest petrenlogu of Just time, in wan*.a.-* * J o J> o i-f-_2297o i THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. s industry is enu^tl by respiratory diseases. One of theso studies showed that pneumonia, in ail forms, occurred in nearly twice the amount among iron nnd steel workers as it did among the employees of other industries, during a 3-vear period of observation (3). A 5-yeur inquiry into the causes of high pneumonia sickness rates among iron nnd steel workers in a representative mill disclosed Iko fact that the largest number of pneumonia cost* occurred in certain depart ments, such os in the blast fumneo and open-hearth steel-making plants.' When one realizes, however, that theso departments contain anywhere from GO to 100 different occujmtions, the task of a pre ventive program is a hopeless one unless definite information is obtained concerning such important factors as (1) tho number of persons in each occupation, (2) the activities associated with each occupation, (3) the health hazards associated with each occupation, and (4) the incidence of pentimorua for each occupation. Such data arc available from an occupational analysis of each department, For example, in tho iron and steel plant under consideration mor bidity statistics for tho ]>cried of 1024-27, showed that 38 cases of pneumonia occurred among the 1,G37 bituminous coal miners em ployed during the same ]>eriod in the mines operated in connection tilth this iron and steel plant. An occupational analysis disclosed tho fact that there were GO diifcrrut occupations in the mines and that 33 of-the total of 3S pneumonia cases were associated with only two occupations--those of pick mining and loading of coal. The pneumonia rate per 1,000 men for miners and loaders was shown, by this study, to bo 31, whereas the rate for all other mine workers was found to be only S.5. It is quite obvious, therefore, that of the CO occupotious involved in the mining of coal, one's attention should be concentrated on the activities of coal miners and loaders, in an attempt to determine those factors in tho industrial process and environment which contribute to tho high pneumonia incidence experienced by those workers. In practice the making of on occupational analysis has for its bass - tho filling out of item 12 of the survey form previously mentioned. Tho data obtained cover such subjects as the manufacturing process, tho raw materials entering into the process, and tho finished product associated with the occupation of each employee. To obtain such data it is necessary for the* investigator to become thoroughly familiar with the activities of each occupation and the processes of tho workroom ns a whole. One must not take anything for granted in a study of this sort. For example, in a study of tlio hazards involved in tho applicntlon of radium paint to watch and clock dials in a certain workroom (4), otto of the employees listed was tho foreman su]H*rvisIng the work of the radium dial paiuters. Upon cltwo study it was discovered that this worker, in udditioa to allotting and supervising pt.i T all Jiletrx(: Of I: pi Ilf. oerti pro!; a( IO` f111.- rtjc Fur. two rmp! tin*::: pm*.! wor!, T!. nifti to (1: tfkrli-1 swell : Samp* Tli** tiuu o rerlto ditt'k- Ci c/5 ---- UJ C5 --| S3 a j J3B 0019971 | THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES,''INC. 2465 if these studied lonriy twice tho :g tho employee* .rvulion. (3). A ness n tes among1 4sd the fact that i certain depe.rtrtk steel-making artments contain 10 Lrsl; of a pre.e information is .) the number of feinted with each cad; occupation, a lion. Sueli data each department. 'omJilemtion. mor el that 3S eases of s cod miners eiuated in connection . n\ is disclosed > im^j mines and ^d^Bcd with only ding of coni. The ders was shown, by r mino workers was :refore, that of the ic's attention should ; and loaders, in an lustrial process and ocumonia incidence lysis has for its basis reviously mentioned, uiufaetuting process, l the finished product rec. To obtain such become thoroughly id the processes of tbo thing for granted in a ` the hazards invoh id cliM*!; dials in a certain the foreman supervis;>on cl'He study it whs oiling and Mijtervisutg t the work of each painter, spent 1 hour a day in mixing paint for all the dial painters and oneo a month blended various radium powders in such a manner that he was exposed to the inhalation of enormous quantities of radioactive dust. This latter brief exposure to radio active dust was of far more significance from the vicwjjoint of radium poisoning Ilian his total exposure during his supervisory duties. Ti;c remaining subject.*', listed under item 12 of the survey form are all of a simple nature, hut are often of assistance iu presenting a com plete picture of the workroom environment, and at times serve to explain certain unusual phenomena. Take for example the subject of labor turn-over. In a certain lead storage battery factory the plant officials pointed to tho small number of lead poisoning eases occurring in their plant to show that this disease was not an important problem in their workrooms (5). Investigation of tho workroom atmosphere disclosed that in the lead-mixing and pasting rooms of tliis plant enormous quantities of lead dust w*ro present, quantities sufficient to produce lead poisoning in a comparatively brief period of exposure, as judged by our present knowledge of lead poisoning. Further inquiries revealed tho fact that the labor turn-over in these two workrooms was vrry great, in fact, so great that tho men left employment before real serious symptoms of lead poisoning manifested themselves. The presence of a high labor tum-ovur in times of normal production is often highly suggestive of unhealthful or unpleasant working conditions. The remaining subjects under the item dealing with employees, need no further comment, since their purpose will be quite obvious to tbo average investigator. It is often very helpful to obtain a sketch or blueprint of the workroom layout, on which may bo noted such important items as tho location o( ventilating systems, points of sampling, and any other data bearing ou the problem under study. These data may then be used in the subsequent tc|>s of an investiga tion of this type, namely, tho recoimuenda tions necessary to crndicalo certain unhealthful or unpleasant conditions which tho studymay boro disclosed. 1 SB PPG IND_U_S_T*RIwESa,sINNCO. TDIAD NROECTOCRODMEOFFROM ITS FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIE- IN<^ 1L THE INSTRUMENTS AND AimiODS USED IN TIIE SAMPLING OF ATMOSPJJEU1C INDUSTRIAL DUSTS CENEUAL CONSI DERATIONS Atmospheric dust nuiy be definied either on a basis of one of its physical characteristics, such as size, or physiological grounds, depend ing on the effects produced on.tho human body hv the inhalation of tho dual. Drinker and Thomson (f), in their classification of duals, fumes, and smoke, have defined dusts ns "particles or aggregates uf particles, 150 to 1 micron in diameter, -that arc thrown into tlio air by inecbanicnl agencies * * * Examples are silica, laic, cement, organic dusts such as bard rubber, starch, nud cocoa; flocculated fume and smoko products." In tho present volume dusts will bo interpreted as particles or aggregates of particles au$i>cndod in the atmosphere end of a size capable of being inhaled (in industry this size is u-.jally less than 10 microns in diameter), and will be considered in two classes, namely, those win'di may be capable of produciug fibrosis of the lungs or oilier respiratory conditions, and dusts which may cause systemic poisoning, ns typified by certain compounds of lead. Since our interest in tho dust problem lias n purely industrial aspect, it is essential that any dust-sampling instrument which one will use should be capable of collecting effectively dust of a size present iu tho industrial atmosphere. As will be shown later, industrial dusts arc mainly from 0.5 to 10 microns in size., so that mi instrument capable of collecting these sizes with a fairly high degree of efficiency will meet tho present-day requirements. The range iu I dust concentrations encountered in industries is very great, depend C" ing, of course, on tho industrial processes,, tho devices installed for V mitigating tho dust created, and the efficiency with which such' ( devices function. For these reasons, an ideal instrument should be ( ono capo bio of sampliug with equal efficiency in both high- and Ion- f dust concentrations. Tills factor calls for tho prerequisite of a dust- ( collecting medium wltich shall not add dust to any great degree to tho dust in tho sampled air. Furthermore, tho collecting medium must bo uniform in dust content, so that one or two control tests on f this medium will be sufficient for a series of samples. Since the dust content of industrial air is ever varying, it is essen tial that tho dust-sampling instrument bo capable of collecting air iu largo quantities ut a rapid rate in order to obtain a representative picture of existing conditions. And, finally, tho ideal instrument will (jm 1 nia uutUMENT WAS NOT A RECORr Jrs RLEsYSf?' INC* 010 N0T C0ME F IT S FILES. AND CANNOT BE AUTHENTIC BY PPG INDUSTRIES, AUTHENTM 1 2467 r IN* TJU: SAMPLING Of DUSTS <3 .m a basis of on*' of its logical grounds, dqn'iuiJy by the inhalation of X clussifti/ation of article;; or agyrega1cs of arc thrown into the air * are silica, talc., cement, ! cocoa; flot-cula led fume dusts will he interpreted nded in the atmosphere iustry thii size is usually ill be considered in two rv of producing fibrosis of .1 tluMs which may cause om ids of lead, h^ purely industrial which one fimn'ciy dust of a size s will be shown Jatcr, .licrons in size, so that an with a fairly high dojtreo mrrmeuls. Tl>e range in ics is very great, depeudtho devices installed for acicncy with which sneli deal instrument should be ;ey in both high- gnd lowtho prerequisite of n dustist to any great degree to rr, the collecting medium mo or two cm(nil tests on of samples. is ever varying; it is cssnncapahio of collecting nir ui to obtain u representative v, the ideal instrument will IX ho one that requires only a simple and fairly rapid method id nnnlysia. Suflicc it to say that an instrument designed for use in the field should oiidmdy nil these principles nml in addition bo light in weight, portable ami compact in construction. To recapitulate, the final selection of a dust-sampling instrument for industrial use will depend on the collecting cflicicncy of tlio device, on its small errors in analysts, on its portability and on the oasc with which a sample oueo obtained may bo analyzed. Many methods have been devised and used for tho purpose of determining the quantity of dust in air. * Knowles (7) lists some S3 different instruments develo[>cd and used for this purpose at one tiuio or another. Because most of these instruments havo proved impractical and arc no longer in use, no discussiou concerning them will be given. The Trader is referred to an excellent review of this subject by Dr. Leonard Giwnlmrg (S). Ilowover, it uuty bo of some interest to review, briefly, the lustory of tho development and use of some of the dust sampling instruments in voguo today. history or* wiESEjrr day ursT sampling instruments Tlio South African investigators began using the sugar tube method for the sampling of atmospheric dust in 1011 (0), and Lanza and Higgins in their Joplin study also availed themselves of tho same technique (10). In fact, no other suitablo method was then avnil- nblo. In 1012 the Committee on Standard Methods for the Exami nation of Air of the American Public Health Association recommended tho sugar tube ns tlio standard method for the sampling of atmos pheric dust. This method of dust sampling had several dmwliaeks, tho chief of which were its slow sampling rate (tho - American Public Health Association Committee sampled 5 cubic feet in IS minutes) "and the fact that tho sugar always contained a certain quantity of dust which introduced a variable, and sometimes considerably doutbful, element into tlio fimd results. * To overcome tho limitations of the sugnr-tubc method, various investigators attempted to devise other procedures for tho sampling and aualyisM of atmospheric dust. One of tlio most fruitful studies was that of Palmer (11), who in ,1016 presented his water-spray apparatus for sampling dust. This method was adopted in 1017 by tho CommiItco on Standard Methods of tho American Public ^llrrdtli Association amLw.ts recommended as tite standard technique for the sampling of dust in air. Tho United States Public IJeullh Service began cmployitig this apparatus in 191S in its studies of dust in air. ., Jn 1910 the South African investigntors, desirous of obtaining a more ]K>rtablc type of instrument and ouc which would yield results </> i1 t O V-'.' ; -- CVr-' I BB Q019974 | ms filesYw IES| BY 552 2468 12 more rapidly, described a new instrument known as tlic Kotr.6 konimeter (12), in this instrument a small volume of air, approxi mately 10 cubic centimeters. Is impinged at n high velocity (30 to SO meters per second) against the surface of a, vaseline-coaled glass plate, the vaseline serving to retain the particles of dust nftcr they strike tbo plate. Tho plate is then removed and placed under the microscope, the adherent dust being counted at a suitablo magnifi cation. The United States Bureau of Mines, which had been using tho sugar-tube method for dust sampling, begun, at once to study tho performance of this new instrument. In 1022, tho instruments mentioned were the ones in most common use. In addition, however, the United States Bureau of Chemistry (13), in its dust-explosion work, employed an apparatus which con sisted essentially of an adapter for holding a WJuitman filter paper thimble through which air was drawn by a suction pump, thus sampling tho atmospheric dust. By tho difference in weight of the paper thimble before and -after dust sampling, tho weight of the dust was easily determined. Finally, mention should be made of the Anderson and Armspach (14) dust determinator which, in 1012, was in uso by the American Society of Heating ond Ventilating Engi neers. Tliis instrument measured the loss of pressure incident to forcing air through a piece of filter paper; this rate of loss of pressure was then regarded ns a measure of the nir dustiness. f^ Very briefly, such was tbo status of the technique of atmospheric--- } dust sampling in the year 1922, when it became apparent (hat tho'~~ various dust-sampling method.-* did not yield results which could ber^ regarded ns absolute or even comparable. In fact, sampling in a given industry, by different methods,usually gave findings which were h'.. not of tlio same order of magnitude. As a result, a conference of * interested persons was held at the United States Bureau of hlines Experiment Statiou, Pittsburgh, Pa., in 1022. It was decided at that time to cond uct a laboratory study of dust-sampliug-instruments. Tiio study was starred in the summer of 1022 at tho Pittsburgh v` Experiment Station. Suspensions of dust (fivo different powdered substances were used) were set up in. aii air-tight chamber and simul- ^ ; tancous samplings were carried out at first with the sugar tube, the > Painter apparatus, tho kouiuictcr, the filter-paper thimble, and the cj dust determinator. j__ __ Curing the course of tho study a new instrument, tlic hnpingcr, for O O tho sampling of dust was devised. `Tliis new instrument was included ZZL ZzZ. In tho later stages of the laboratory study of dust-sampling instru ments described in the rvimrt published as Public Health Bulletin No. 144. In this instrument the nir to lie sampled is drawn through a glass tube and impiuged ut a high velocity oil a glass plate wliiriris kc*-' -- ^__ rsTooSi~- THIS DOCUMENT WAS NOT A RECORD PPG INDUSTRIES, INC. DID NOT COME FF AN CANN0T BE AUTHE.MTICA BY PPG INDUSTRIES, INC. . tunWT ns the Kt7.6 lump, of air, appro*ihijth velocity ("u to va*i*line-co;tlcd glass ns of dust after they nl pinned under the t n suitable magni.'ivhicli liad been using tin nt once to study ones in most common Bureau of Chemistry Apparatus which coniViintnian filter paper suction pump, thus cure in weight of the g, the weight of the i should he made of nator wliich, in 1022, ar.d Ventilating Engipressure incident to -itc of loss of pressure ine** mi f atmospheric m^^iarcnt that the vMKf wliich could bo n fact, sampling in a vo findings which were vault, n confereneo of utes Bureau of Mines l. It was decided at -sampling instruments. 922 nt the Pittsburgh vo diiTerent powdered lit chamber and siniuldi the sugar tube, the aper tliimblc, and tho aient, the impingcr, for ut rumen t was included ' dust-sampling instruPuhlia Health Bulletin drawn through a glass ass plate which is kept iii Ii i ! 13 ' bcuenth tho surface of the water or other suitable fluid in tho collectiug flask. Tim dust is momentarily arrested, wetted by tho collecting fluid, ami in this manner trapped. After a sufficient volume of air him been sampled, a portion of the collecting fluid is removed to a suitable counting chamber or cell for microscopic count to Ascertain tho number of particle* in a manner to bo described Inter. The re-, maining portion of the sample may bo subjected to any desired analysis. In the comparative study the dust-catching efficiency of tho impinger was found to ho high. Consequently, its physical principles and characteristics were the object of a special study, and finally a satisfactory and practical form of dust-sampling instrument, based on lids principle, was evolved. The apparatus (essentially in its present form), ns described in Public Health Bulletin No. 144, possessed an efficiency of 94 to 97.5 percent when sampling a finely divided silica dust suspension at the rate of 1 cubic foot per minute. The tests used in estimating this efficiency were conducted by an optical method in wliich a portion of the dusty air being delivered to the collecting device was diluted with measured amounts of dust-free aii until a "match" was obtained on comparison with tho stream of air emerging from tho dust-col lecting device. Tho comparison, or matching, consisted in producing equal Tyndall effects (equal amounts of reflected light) by the two dust streams when they arc simultaneously observed in a beam of light. So far as the quantitative results of the dust-sampling instruments ere concerned, the conclusion of the comparative study was as follows: Confident!- tho dust caught hy the Palmer os unity, tho instrument* take the following order; On basis of numbers of particles determined--impingcr, 6.0; sugar tube, 2.1; and Palmer apparatus, 1.0. On basis of weight of dust deter mined--Lmpinker, 2.1; thimble, 1.5; sugar tube, 1A; Palmer apparatus, LA These results have led to the selection of the impingcr os the most efficient apparatus for ell-round industrial dust sampling. Tho instru ment Los been used in a number of studies in the dusty trades, in tho studies of lead tetraethyl, and many other investigations to be mentioned later. Twelvo years of field experience with tho impingcr Apparatus have given confirmatory evidence of its value as a dustsarupling device. DKsciurrioK op pnKsnxr-pAir dukt-sauflxxo wsrotmiaras ~ Of tlio various instruments mentioned in the history of tire develop ment of dust-sampling devices, two which are nt present finding some use in dust determinations were developed since 1922. Theso are the Owen* Jut Dust Couutcr (15) and Drinker's modification of tho S rn I-U O t-- c.:- C~ c LU oo I BB 001997** l ... ,--was NUPA REC0 PPG INDUSTRIES, INC. DID NOT COME IT'S FILES AND CANNOT BE AUTHENT1 BY PPG INDUSTRIES, INC. f>r.170 14 clcclrienl preeipilntor device for dust, collection (1C). As a result of the comparative st udy earned out in l'J22, the Palmer, and tho Anderson und Annspacli dust dcLcrmiitnlor are employed very little for dust sumpimp at the present writing. Tho instruments employed in dust studies aro practically limited to the following: Impingor, Electrical Precipitator, Owens Jet Dust Counter, Pnper Thimble, mid ICotze Koninieter. Tlio text which follows describes tho working principle of each of these five instruments, their construction and use, and their advantages und disadvantages. ' The Gcetbi;r-Si.ii(lt ii.kpincer The impinger apparatus (17) consists essentially of two portions: First, a source of sufficient suction to draw tho uir to be sampled Tm 3.--T>n.rin* fImSeUly driTm nrtiea anmrM. lap view. / through the sampling device; and, second, the sampling devico or imptngcr itself, which consists of a container and tho impinger tube and plate. As a source of suction, an electrically-driven and a. com- " pressed-nir-driven apparatus have been designed. A linnd-driven apparatus developed at the-United Stales Bureau of Mines will also , - bo described. p" * Jdeetne tuetion ajyianitiis,--Tlio electrically-driven suction np- r_--; peralus is designed to ho used in places where electrical energy is ^ r> available. A photograph of the apparatus is shown in fipiro 1, and the mechanical details are presented in figures 2, 3, and 4. Tho motor is a series-wound, single-phase, GO-eyclc, one-fifteenth h rsc- power, ratctl at l.G amperes, at 110 volts, with a speed of 1,SOO revolutions per minute. This motor, being series-wound, operates on either alternating or direct current The motor is geared to a rotary eccentric jxwitivc pri\s.*uro blower' by menus of a set of gears having A 1 to 3 ratio. In order to minimize noise, tho smaller of THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. i_BB 0019977 | As a result of the 3'altner, nml the Audeivon doyed v:ry litlh: for dtisl inunvats employed in du.-L wins: Iinpingvr, IChvlriral 'a Ijot Thimble, and ribcs the working principle construe! nm am) use, and essentially of two port inns: raw the air to be `-.miph-d -C3, [m T r . r r . t e ^ , . . A M M ; r M T H jO acitoa apitaruu** tup view. ond, the sampling device or taincr and tho impmger tul>c lectricjdiy-drivrn nml a comn designed. A hand-driven tes 33ureait of Mines will also rctricaliy-driven tuietion np:os where electrical energy is itus is shown in figure 1, nnd in figure* 2, 3, nml 4. Tho GO-evcht, oue-lifieer.tli lu>rsevolts, with a s|>oed of 1,S00 being series-wound, operate* t. The motor is giant! to a .ver by means of a set nf gears muimizc- lioiso, the smaller of Picurc 1.--CucrmcALLV Driven suction apparatus for imfincxr. [ BB 0019978 | THIS DOCUMENT WAS NOT A RECORD Of PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 15 lr wheels is made of filwr, Iho larger bring metal. The lilowrr Li rated at 4 cubic feet of free nir per minute when routed lit a sjiee<l of 000 revolutions per minute, and is used as a source ,,f suetiim rather tbim as a source of air pressure. Wired in series with (he electric motor is a OS-obtu, l.G-nmpcro variable sliding rheostat used for rpced control of the motor. By employing such u rheostat a voltago of ] 10 or 220 volts may bo used. To tiic intake or surtinn side of the blower is attached a }*uieli malleable-iron I J fiavit ikdrinflr drtvtn note apfiMitiaifak vtov* y emmertod to ft constriction-typo glass flowmeter by means of a suitable length of noucollapsiblo rubber tubing; tbo flowmeter is fastened on tbo inside of t he lid of the carrying case. The inlet side of (ho flowmeter is connected to the sampling flask by means of a second piece of noncollapsible ruhber tubing. Tbo latter picco of niblter (ubtitg nuty be of jury snilubio length. Tbo flowmeter scale is ntltbniletl in a manner to bo described later. A vacuum gego may **" used instead of a flowmeter us a measuring device for the air flow. | BB 0019979 | THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC.. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 2473 1G TJ'n electric motor, blower, sibling rheostat, dectrie plug, and switch nn4 all assembled on a metal plate 9 by 14 inches aiul % inch in thickness, and this plate is in turn firmly screwed to the baso / \ 7*-------------- ^ \* ] , t @=^= 1 \. ______ y ------------ ----------------- k .. y - rf_ terme/riur Cuter VMmn t"llwli>j(IWilirtrOriwiwtliw mpps*Uri, rad *tow. of the currying case. The carrying ease is made of J^-inch quartered oak, the outsido dimem-ions being 10J-' by 15}i by 0}i indies. Tlie weight of tho apparatus is 45 pounds. Comprt.*art}-air suction apjmratu*.--In many industrial establish ments, mines, ami quarries, cnmprcfved air is readily available. By means of a very simple devien railed an ejector, tho energy of tho nn ______ 7'BB-00222-2-1 5 electric plug, anrl 0 by 14 inches and % raily screwed to the bus .--.--6 #**#* *** m 3|l|WltM Md dfw. made of jf-lneh quartered lSJs by 9)i inches. Tlic i:my imhif-trinl cstablisli is readily available. By Jeetor, the energy of the 17 coinprt'ascd nir may bo converted into suction ami then utilised with thnimpinger tube and flask for the sampling of tho dustin air. Hatch lias recently described a suction device of lids tyi which has tho added feature of a constant flowmeter (IS). Detail* of this iustru- incut are presented in figure 5. This device uses about 50 cubic feet of free air when functioning and u constant rulo is obtained with it regardless of tho variation ju air pressure, so long ns this pressure is within tho limits of 30 and 75 pounds per square inch. For an indicating device a simple pressure gage, connected to tho compressed air supply, is employed. Tlio constant flow in this meter is due to the fact that the pressure drop across the oriJice (jh--ih) is greater than the criticul pressure, which for air is 0.53 yt (where y, is the upstream and p* tho down stream pressure). Under this condition the flow* depends upon pi only, and since this remains consinnt (within tlio O< .o limits of Imrometric pressure), the rate of jyj^cTO/? air Aow luis a con L-- stant value. With a barometric pressure y __ equal tO 30 inches of J,nn,, n -rni-ijirrmml l*rtlriiTtimnkw | mrttnr fnr tmrtimr mercuryand tbepres- suro loss through an impinger device equal to 2.9 inches, pt*27.1 inches. To meet such n requirement p,--p,*14.5 inches ("0.53 p), and fo (absolute) must be less than 12.6 inches of mercury, that is, --17.4 inches of mercury gngo pressure. A suction in excess of this vohia is obtained with the aid of a Xo. 2 Hancock ejector, when the pressure in tho air line is between 30 and 75 pounds. The orifice os U designed by Hatch and his co-workers was fouud on testing to yield rates of flow from 2S to 29 liters a niinuto (about 1 cubic foot per minute) with a maximum variation of 3.5 percent. Itundrdnmi tveiiun ayjmrulua.--Earlv in the course of the studies at tlio Uuited States Bureau of Clines Experiment Station at Pitts burgh, tlic necessity became apparent for a lamd-netuated apparatus, lo lie used in work places lacking electric power or compressed air, Sueli a device was designed and constructed and is fully d&cribcd in 1`uhlir. Health Bulletin No. 114. Tho apparatus in its present Idem (lg. 0) consists of a t rijiod of metal tubing supivorting a vertical post ami n horizontal bar ut its apex. Tlio horizontal bar is provided with an ordinary bicycle seat. To tho vertical post at a suitable level (adjustable) them is attached ft lmsitive pressure blower (used as a -iireo of stte(iou) of the same size and cajiacity as that used with the --^ ] BB_0019981 | THIS DOCUMENT WAS NOT A RECORD C Pr>G INDUSTRIES, INC, DID NOT COME fRO IT'S FILES AND CANNOT BE AUTHENTICATE BY PPG INDUSTRIES* INC. 2475 wjixuit ii IS clectiieally-driven typo of apparatus. in this case, However, nit of the excess mclai of tiio blower has Immmi rumnvcd hy machining in order to reduce tho weight of the tijipnratus. Tho blower id geared to n pair of cranl: lmndhs by a pair of gram having an $ to 1 ratio. Tho auction inlet of the blower is attached Co the impinger sampling bottle which is supported near the top of tho vertical post of the tripod. Tho steel tubing of winch tho tripod and Its appendages are con structed may bo dismuullud and tho complete apparatus fitted into a canvas case somewhat resembling a gun case. Tho weight of tho complete apparatus is approximately 17 pounds. A revolution counter attached to the large gear records the number of its revolutions. Calibration of the instrument with a gas meter allowed that the volume of air sampled per revolution of tho pump O- Jftff?1--e*o-- 170 1oo so to o n1o - 12.0 RtVOLOflONS or HANCOC, PCS mmotc Ttevsz T.--ColiUmlon tort* otrotary pomp tor Wnlrlrafaction ipasstaj. --* 130 c. ( c. 144. The particular pump tested aspirated 1 cubic foot of air per minute when operated at 02 revolutions per minute. When the apparatus is in use the operator turns the crunk at the rate of approximately one and one-half revolutions per second, 'maintained os constantly as possible, for as appropriate length of time. The number of revolutions- ]x>r minute is determined l>y dividing tho total number of revolutions by tho time of sampling. From a curve similar to that shown the voiumo per revolution is calculated, xvliicb is multiplied by the number of revolutions to give the total volume of air sampled. For general field use, tho compressed-air device lips been found to l*e the most satisfactory form of apparatus. Jitpinger tube anti sampling jlaxk.--The impinger tube in tho 4nod3 of tho apparatus described in Public Health Bulletin No, 144 2476 r- ease, However, till of ^Mioved by iiuirhiniug in -to*. Tbo Lhmvf is geared ..`ira having an i to 1 ratio, d to Uicitupiugrr r-mnpling >0 vcrtfcel postof the tripod, id its appendages arc conipicte apparatus fitted into a ease. The weight of the pounds. ze gear records the mnub. r itrument with a gas meter >er revolution of tiic pump O IQ i - j v i v 'f- x lix O N -C. sett mnutc "WilTii almi nppMaUM. '**. Tlie calibration curve 'ubCe IIcultU Bulletin No. ?d l cubic foot of air per -r minute. or turns tbe crank at the rcvoluti ns per second, an appropriate length of ainutc is determined l\v i>y tbe tinio f sampling, v luino per revolution is I>cr of revolutions to five device has been found to impinger lube in the Health Bulletin No. 1-14 CO UMENT WAS NOT a RECORD OF jnilSTR'.ES INC. DID NOT COME FROM iles AND CANNOT BE authenticated >G INDUSTRIES, INC. i * 2477 10 (p. OT'l consisted f a piece of Pyresc glass tubing, drawn down to a lip with a 2.3-milliuietcr orifice. To (bis tube a metal tripod and circular impinging plate were attached by means of a bronze split* O '-*? t f *lr*vn clomp. The distance between tho orifice and the upper Mirfuce of the pinto was kept at 5 millimeters. . In practice, this impinger tulo yielded satisfactory results. Never* itwIcsM, it was felt that it would be preferable to eliminate the use f uieliil, particularly where arid or alkali was to bo used ns the Mvliug lliihi. .Accordingly, there was designed* and constructed *! all-;'lass impinger tills* sluwn in figure S, with circular glass THIS DOCUMENT WAS NOT A RECORDS PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 1 BB 0019984 1 2478 20 impinger plate slxiut 2.5 millimeters in din meter, fixed by three supporting rods l>oiit 0 centimeters loti" to Ilia impinger tube at s distance of 5 millimeters from the orifice. Th6 tube was 13 milli- meter* in outside diameter. Fyrex glass was used throughout. Tubes of this type liavo been employed without an unduo amount of breakage. A few modifications bare been made in tbc impinger flask. Origi- nally, a round 30-ounce glass bottle fitted with a 2-hole rubber stopper was used. A short time later a 500-cubic centimeter Pyres glass assay flask (wide-mouth conical Erlcnmcycr type) was substi tuted, wltieli proved to be very satisfactory. In certain studies it was found desirable to obtain dust samples in the region of tlic mouth and nose of a worker in order to secure a more representative picture of the air actually breathed. This was done in a very ingenious manner by the Australian workers, Badhnm, Bayncr, and Broose (10) who utilized as tho sampling flask a cylinder 12 inches in length, and 2 inches in inside diameter. Tho cylinder n was fastened to the worker by a specially designed strap pnssingUniUacfvi the chest. We have employ-id a similar flask made in tho fonprof a"^j. tube sealed at the lower end, 300 millimeters in length and 50 nulli- ^ " meters in dinmeter, provided witli tlie 2-hole rubber stopper (slLewn in fig. S). For protection from the impact of large pieces of flyiiig material, as well ns for convenient support, the tube was placed inside of a cylindrical leather bolster which in turn was made fast to the chest of the worker by means of a pair of straps fastened about tbc chest and shoulders. Thus, the- inlet end of the impinger tube was fixed nt a poiut very close to the nose and mouth of the wearer. As before, tbe outlet tube from (bo sampling cylinder is connected to tho sourco of suction by means of a convenient length of noncollapsible rubber tubing: Figure 0 shows this form of impinger sampling cylin der with its leather holster, as used in our studies. ' Whether bottle, flask, or cylinder is used, sufficient liquid should be. kept in tho eontaiucr during uso to cover tbo impinger plate to a depth - II, of approximately 3 centimeters. Jn tho eyliuder type of flask 100 cubic centimeters aro sufficient to accomplish tfiis, whereas if tho Erlcnmcycr type of flask is used, 250 cubic centimeters are required. A bafllo pinto on tlio exhaust tube, as shown in figure S, is sometimes advantageous. A more compact and convenient impinger flask and nozzle has been recently developed for field uso (IS). Tho modifications in the design of tho impinger have in no way altered tho basie principle on which tho instrument operates. Figure 10 shows tho latest form, f 1 the impinger flask and nozzle. Tbo modified impinger does away with tho glass impinging plate, utilizing the bottom of the flask for this purpose. Tho suction con- \ ^ ^ , 7~Bb"*0019985 | THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT Bt AUTHENTICATED BY PPG INDUSTRIES, INC. I O diameter, fixed by thris* to the. impinger tube at n The tube was 13 mil!)* s whs used throughout, without an undue amount he impinger flask. Origied with a 2-bole rubber 10-cubic centimeter Pyres iimcver type) was substi* to obtain dust samples in r in order to secure a mom breathed. This was done traliaa workers, Badham, a sampling flask a cylinder 3 diameter. The cylinder igned strep passing around ask'made, in the form of n ers in length and SO milliole rubber stopper (shown :t of hirgo pieces of flying tb' o was placed inside made fast to the sSP* fastened about the of the impinger tube was mouth of the wearer. As ; cylinder is connected to ?nt length of noncollapsxblo >f impinger sampling cvlinstudies. , sufficient liquid should be o impinger plato to a, depth nrlinder type of flask 100 plish this, whereas if tho ; centimeters are required, n in figure 3, is sometimes ugcr flask and noz.do h;:s Tho modifications in the ered tho hash; principle on 0 shows (ho latest form of tho g!u.-*s impinging pla(, urponc. The suction cou* THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. CA CO UJ "d * 'ii tiL:- -D o | BB 0019986 | 2480 Oi necftott w combined with the inlet tube, Hum simplifying tlio device htUI further. Tho essi-nthd jiortious of the Uoviro consist of a straight piece of Pyrex glass tubing 15 mm in outside diameter and approxi mately 275 uun in length. The tube U drawn down in stream-lino form at its lower end, to a tip with a 2.3 mm orifice. In sampling this orifice is kopfc approximately $ mm from Uto bottom of the flask, a guide lino on the flush indicating this distance. Tho flask is 50 mm in. diameter and 210 mm in height and requires a fluid (water) volume of oidy 75 ee to give tho proper depth of immersiou to tho nozzle. Of. f I f O CO tr- Vii m. i j Iwas la-Pnwte; nwllftrt laptop ad f w^ ittfc wuiwUd> ffttriftraUw. An entrainment trap in the form of a rubber ring prevents the possible loos'.of tbo liquid (and dust) with tho outgoing air. Since the impingement distance in this instrument is not fixed, as in (bo previously described type, it was necessary to determine the I limits within which this distance, as well os tlio angle of impingement from the perpendicular, varied. Studies conducted on tlicso factors by (lie designers of tliis instrument showed that as regards tho aug)e of impingement (using silica dust) one can have a maximum displace ment of the nozzle without changiug tho efficiency obtained when tho Uuzzib a in tlio vertical position. Also, it was found; that the im pinging distance can be varied from 2 to 12 millimeters without impairing tlio efficiency against silica dust to any appreciable degree. Tho data pertaining to tho experiments mndo on this modified dovico am shown in tlio following tables, 4, 5, nnd 6: | BB 0019987 J THIS DOCUMENT WAC NOT A RECORD OF PPG INDUSTRIES, INC. DID N0T-C0ME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 2881 22 Tahu: 4.--lifftet of impinging dul nee on ejhcicncff of impinger |rfam|>U ral*SU IJi*iw ]r itiiiuil*| Tahu: 5.-~ICJftrt of verging angle of impingement luminous di/t3or*-5 mm: aunpHn; raic-2&3 liiwm ivr minute] iil|nUiintiiIiplW>M<tk rRM vffiticnar StilM VnanU MiUW.i. um main Minimum mdetrom jmr--nditiilar.__________________________ l'criuidiruUi....... ............ .....................--.......... ............................. T* M.TT +W *'A*S ilnlliwiilM. > At lilth sail itnr amendMmol re*ptjv*J7. CD J7 Tahu 0.--7i^crt of earntiling rate an ejjidenty of impinger fttnrtndnc mm} lTrcmt iUxinwr BarnaUiiS mi* (Ilm \*t minute) SOkn Tobacco smok* MaenminaatMo Wt n*y Molinm Ho* *>.n_________________ .. . ---------- --sr mu .... ................. sxe____________________:------------------------ ------- .. ... . .. ... . M m Sift .. .. . ... , || - HH StlA ...... -* sr 7* wt *4 w s to -- 73 79 77 KM eed 15 3S -- Method of tnmpUng--Calibration, of the. impinger ap/Kin/tus.--It is necessary to calibrate tho nir-measurinff device of tho impinger appa ratus so that ono may control lire rale and quantity of nir sampled. Tho technique employed for this pnrpoo with tho hand-actuated auction apparatus has already been described. With the electrically driven suction device a suitable llmvuieler or vacuum gage is com monly used as tiro measuring device, while, the ejector instrument t i i I i i I *- 1" .* , ; T-1 o it- i.:. .1. i | BB*"oo"l 9908^2 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 2482 :icMj of im/tinker i'mnti *0eMtc7 i \fxm rrim\ti Mapm-wat Miikt l Orr Mciliipu Fit*. *H4 ST *1 *4 u i n M rr 7$ 5US1A &i arpinprtneni 'm j-r minnicl . ^ Ivan; tny-imr 80km WatNuvU WKUlllk v ' n W.JT sw.,i Q n >>4^. rttwtlv*iy. impinger hnattMidnqr otcTn wn.li XlacmviMm U0a Hit MmIIimb iw sr D r n it TB tr _i ____ , _ 2 , 77 I s aat vpivtftr apparatus.--ft Is ice of the impinger nppaquanlily of air sampled, v.'it'.j the hand-actuated *d. With the electrically or vacuum gage is com ic the cjiftor instrument 23 uses a pn*s.-*-mo pego ns tin indicator for the tiir flow through tlio impinger. J*`or calibration, the apparatus rliouUl lto assembled in n maimer precisely simihir to that employed in field sampling, but with the outlet t uIjo of an accurate five-light, dry, test gas meter attached to tho inlet of tho impinger apparatus. A calibration curve is then obtained, showing tlio relationship between rates of air flow, ns measured Ivy ihn gas meter during observed intervals of time, and the readings on tho scale of the flow tuolcr or vacuum gage. The scalo reading corresponding to 1 cubic foot per minute may then bo ascertained. Tho ur-measuring dcvico rhould bo calibrated at fre quent intervals and always after any readjustment of the apparatus. In tho field, tho predetermined reading should be maintained through out tlio course of each sampling period by adjustment of tho uocdlo vnlvo. Prior to the taking of dust samples in tho field it is important that (hi suction apparatus ho careful)}* inspected and completely denned so os to insure proper functioning wlmo in use. Caro should be exercised to insure against leaky connections in the nir circuit. Choice and prej>arotioa oj samplingfind.--In spite of the generally contrary belief, many dusts, including even silica, are soluble in water (20). This is to a great extent duo to llic largo surface area cx)wsed to tbo solvent by small particles of suspended material. A projicr sampling fluid should ho used in order to avoid solution. As a mlo distilled wafer is used and by conducting the analyses within 21 hours, it is possible to avoid significant dust loss. Preferably, tho counting should bo dono on the day of snmpling. In tlio case of those dusts not easily welted by water, such as cool dust, a mixture of 25 permit alcohol and 75 percent water yields excellent results. Tlio alcohol increases tho welling power of tho solution and at tho same time greatly'reduces tho solubility of mineral dusts in water. IVmmUo action on tlio rubber stopper of wltalever collecting fluid inny bo chosen should bo appropriately controlled. lib important that tho sampling fluid itself bo comparatively freo fnnu Hu*|vndi>d mutter. Distilled water sliould l>c prepared, if possi ble, by one of the continuous types of water stills and, after distillation, siiHuld be permitted to slam! for ubnut 2-t hours, tho upper part being drawn oIT for use. If alcohol is employed, it should bo redistilled Ivefore use. I'rr/Hirution. of MimjJiitg jlnxl*.-- Prior'to taking samples in tho ti**ll tho <h*sired nittnlicr of sampling flasks aro thoroughly cleaned *nl hoi cleansing solution, rinsed several times in tap water, anil uislly riusetl with tho fluid used as tho snmpling'medium. The pjht.i aro thonuighl.v freed from adventitious dust by several washH,,'s m lap water and finally in lhc sumpfiug fluid. Tlio required Iv.VII" CO U.1 i a - _<** 1 \ $ 4.5 O # THIS DOCUMENT WAS NOT A RECORD pPG INDUSTRIES, INC. DID NOT COME FR IT'S FILES AND CANNOT BE AUTHENTICA1 pY PPG INDUSTRIES, INC. | BB 0019989 J f amount of sampling fluid is placed in each impingcr flask, a cleaned solid-rubber stopper is put in place, nud a cup of paper is fastened over tho top by means of a rubber bund. Tbo flasks aro now ready for transport to iUo place where samples are to bo taken. Field technique in aamjdbg.--In taking dust samples tho location of tho sampling place, tho time during which sampling is conducted, and the duration of sampling are all chosen in an ctTort to obtain the data required by tho study in progress. Obviously the requirements of Uio study under way govern the procedure to bo employed. Tho two-holu rubber stopper fltLcd to the impingcr tubo and exhaustelbow may bo transported in a spare flask containing somo of the sampling fluid. Such a procedure serves both to protect the impingcr tube and to keep it dean and ready for use. The e.vj>osed ends of the impingcr tube and exhaust elbow should always be protected against accidental contamination. After the selection of the sampling position, the stopper of one of tbe impingcr flasks is replaced by the two-holu rubber stopper con taining the impingcr tul>o and exhaust elbow. Tho solid stopper is put on the spare buttle, thus protecting tbo rinso fluid and a; the. same tirno preventing conlanunation of the stopper. Tin's com*. ploUly equipped impingcr is now placed in tbe leather holster, wliileC^ the bolster in turn is securely strapped about tbo worker or hdd by! an assistant at the desired sampling point. The holster serves a two-7 fold purpose: First, it serves to protect the glass tubo from breakage! by flying objects in tbo work pluce, and second, it fixes the entrance to tbe impingcr tubo very* dose to tbo nose and mouth of the worker. The outlet or Miction dhow of the sampling lbsk is connected with tiie source of suction by means of a suitable length (commonly 25 feet) of noncollajjfuble rubber tubing. In certain cases it is not feasible to place the impinger flask about the neck of the worker, nor is it convenient to luive an assistant hold tho flask near tho worker.- - Under theso conditions- a length of rubber } tubing (about 15 feet) may bo connected to the inlet of the impiuger apparatus (the impingcr tube) and the free end fastened at tho desired L sampling point. "With a sampling ruto of 1 cubic foot per minute, ^ dust particles pass through a %-inck tube 15 feet long in less than a -- second, hardly sufficient time to allow settling to take place. The duration of tho sampling period should bo such as to yield a satisfactory suspension of dust fur analysis, and is thus dependent on tho concentration of dust in tho atmosphere.* Under tho usual industrial conditions, samples of from 10 to 30 cubic feet of air arc sufficient to yield enough suspended dust for analysis. Since o sampling into of 1 cubic foot ]>cr minute is maintained, this will require a sampling period of from 10 to SO minutes. A stop wutch is used to measure this period. f*BB 00199gg,j WOT A RECORfTOF INC. I 3484 impinger flask, h dramtl cap of paper is fastened Tho ilu.-ks arc tmv n.-;:<ly dok taken, dust samples the location eh sampling is ctmduoicd, . in an effort to obtain the bviously the jronirsmerstj ire to le employed, impinger tube and cximtsl .k coutnining sumo of tho ith to protect the impinger . The exposed ends of the Iways bo protected against don, tho stopper of one of >holc rubber stopper conbow. Tho solid stopier is the rinse fluid and at the tho stopper. This comn the leather bolster, wlrile jout tho worker or held by ' ' loliler serves a two rn tube from hnnknge ec^Plit fixes tho erdranee c and xnouth of tho worker, ling flask is connected with table length (commonly 25 eo tlic impinger flask about nt to ltavo an assistant hold . auditions a length of rubber to tho inlet of tho impinger o end fastened at the desired of l cubic foot per minute, o 15 feet long in less than a .tling to take place, should l*c such o* to yield a sis, ami is thus dependent on nesplien*. Under tho usual 0 to 30 cubic feet of air are dust for analysis. Since -mo is maintained, this will > SO minutes. A stop watch 25 After the sample lias been taken, the impinger tul>o is withdrawn. The tui>c is rinsed both inside and out with soma sampling fluid from a hvsh 1Kittle, tlx*, rinsings being added to tho original sample and the sampling flask stoppered and rapped for transj>ort to the laboratory. Should tlic impimrer tube be. found to bo contaminated with adherent dust after ringing, it should bo carefully cleaned or, lwlter still, replaced by an unused lube. Simro tubes should always be carried. Notes are promptly made of all the pertinent data with rcfcrenco to each sample. ALT1T.XATIXCT CURIU3CT TOXCimaTOB Professor riiilip Drinker and his colleagues at the Harenrd School of Public 11cult!i ltavo had a. good deal of experience during tho past 12 years with electrical precipitators for collecting atmospheric particu late matter. As a rcsidt of their work they liavc found that nanrectified alternating current is superior to rectified current for pre cipitating dry, }>ooriy conducting suspensions, such as most industrial dusts of hygienic significance, Figures 11 and 12 present tho essen tial parts of such precipitators. Tho tubes are made of pyrex of a rise called for by tho particular pr >blem involved. Tho large tube shown in the drawing is adaptable for dust sampling nt 15,000 volts, whereas the smaller tube is used at lower voltages end rate* of air How. A General Electric Co. luminous-tube transformer is used for obtaining high voltages. This transformer unit weighs 22 pounds, o|ierates from a. 110-vult, GO-cycle line and furnishes a secondary current of 30 iuilliainicres at 15,000 volts. By means of a rheostat in the primary circuit, the voltages can be regulated from S.000 to 15,000. In this apparatus the midpoint of the higli voltage winding u grounded to tiie metal casing of the transformer. Fuses are plnecd in both the low-tension lines, rather than in tho main line, so that these fuses blow in case of a disruptive discharge. A rather Hue wire of gold-plated drill steel is used in the larger >4xe tube for the proripitatingor central electrode, whereas it has been found best to uso fine platinum, gold, or copper wire in tho smaller lube*. The outer electrode is made of cither metal netting, of metal foil, or of copper wire wrapped spirally along the tube. Such wrap pings must be pulled tight by bund and may bo kept in place by elec trician's tape. Celluloid foil or filter pni>er placed inside tlic tube is i? **d ns the collecting medium. The precipitating electrode must be kept veil up the tul>o to insure efficient collection on tho celluloid foil >r filter paper; this precaution precludes dust from being caught on the i bf.* lulst itself. t'inre. gnsiM of n toxic nature may Ik* produced in the operation of he |.n*ei;ii|cii(>r, and moreover, since these pises destroy tho rubber - lopiM-rs and tubing used hi tho device, it is advisable to insert a O '/5 -- -i.l L. .J i-- .3 oo 1 BB^0019991*7 wvv/UWtNT WAS NOT A R fPG INDUSTRIES, INC. DID NOT CO IT'S FILES AND CANNOT BE AUTHEI BY PPG INDUSTRIES, INC, 2485 2G chamber containing a^tivattnl chnrrnal 5n the p'nruit (sec sketch) in order to nlnorb thexc lit view of the destructive ncliini of the on the rubber jiarte of the apparatus it is advisable Unit tlio instrument he inspected frequently for damaged parts. As ft source of suction one can use cither ft compressed air ejector, with a calibrated gin** |Imvmeter, or a haml-ftizo vacmim cleaner fan employing n small metal orilicn meter for measuring the air flow. Tins resistance to oir flow of the precipitator tube is small, so that THIS DOCUMENT WAS NOT A RECORD OF pPG INDUSTRIES, INC. DID NOT COME FROM |T'S FILES AND CANNOT BE AUTHENTICATED gY PPG INDUSTRIES, INC. 2486 i^fe.ircttit (*co sketch) destructive action apparatus it is advisable cntly for damaged parts. all tlie resist amu* lo le overcome is duo mainly to tlio charcoal trap. At a sampling rut of about f>0 liters a minute, lids resistance has been found to ho 10 to lo cm water gage. Jn operation a sufficient volume of air is passed through the pre cipitating tube to yield a visible de]osit of dust. The foil or fillerpaper containing the dust deposit is then removed from the tuba and placed in a receptacle for transmittal to the laboratory. Tho practical operating efficiency or the precipitator is nearly 100 percent. If low* efficiencies aro obtained, lliey aro probably duo to either liigli rates of air flow*, low voltages or too great a diameter in tho tube. 5 Si y I <St f*' 9 9* as l in'iiT A emnpresinHl air ejector, hand-size vacuum cleaner fan r f*r measuring ihe air flow, .ijntator tube is small, ?o that en O &- C cr C (. k' fisru IX--Domfe* ari*nMSil*lM(l*7netpnc(ai>aiwtiifaML U-; ^ L>p- v-- oo factor* which may l>e easily corrected. Tlie melliod of analysis and the various advantages and disadvantages of this devico will he discussed at tho end of this section. A list of enutpmen t for collecting dust samples by tho precipitation method is given by Professor Drinker in bis article appearing in tho Journal of Industrial Hygiene, hr December 1032. patui nmiBut sprAiUTUs - Paper filters for collecting dust in, air have liecn used for many vt-.irs by uiitnerous investigal-ors. 'In 1D05, Simon in Germany *miI a paper thimble foe determining dust in blast ftimneo gases (21). Mariner ami Hoskins utilised this principle in studying tho extent of pollution in Chicago in 101 "> (22). However, it was not tmtil lv*.*2 ln-fore diTniile data were tivailahlo on tlie various eliaractcris- BB 0019993 | THIS DOCUMENT WAS NOT A RECC PPG INDUSTRIES, INC, DID NOT COM! IT'S FILES AND CANNOT BE AUTHENT &Y PPG INDUSTRIES, INC. 2487 f 2S tb*s of this device wlu'ii Tnwli'l and 1'rovert reported the results of llioirstudiesof the paper thimhie in connection with lliodevelopment of Ihi* instrument for the collection and examination' of explosive dusts in nir (13). l>itrr>r-iion of apparatus Figure 13 shows the details of the tliimlile ami brass cu|>sulo which holds it in place. The thimbles used arc single thickness, 'W'hulmau extraction shells, 33 by 94 mm, with a small amount of cotton wool (weight about 12ii ing), well llufTvd out, inserted insido tlio thimbles for the pur|Ktso of aupjHirting the dust and to preclude the possibility of eloggmg tlio pores of the puper. The suction side of tho capsule is connueted to either a calibrated fN>t pump, an electrically driven blower, or an ejector device of the type described with the itnpinger Outfit. In oj>eration tho dust-laden nir enters the opening of tho brass capsule, us indicated in the sketch, pusses into the paper thim ble, and after drifting the dust. e-tea pea into (he expansion com partment of the capsule and thence through dm suction device; 1 BB 0019994 | il..- 1 * j.i i:. : t:. Thi I <* ? i lilii \ V. ' \ .it i; |- i (* Illiiiii ls*t til 1*1 in th Ml>* l! u!ii* It;:ii 1* *. ..fl.-r A .* 'p; iii*ii * Tli* no*? *-(* ...II: * out ! I . it- i!w* \ a i*i T* UI i. > \ , i THIS DOCUMENT WAS NOT A RECORD PPG INDUSTRIES, INC. DID NOT COME FF ITS FILES AND CANNOT BE AtfTHENTlCA' BY PPG INDUSTRIES, INC. . 2488 N O TE: T ^!,n n o rM iM F M T p |[) ported tho nstdts of will* Iho development uiimtiou of explosive J bras* capsule which thickness, "Whatman at iaining rice > mount of cotton wool' cd insula tbo thimbles UTclmlo tlic iwwdhility a side of the capsule is an electrically driven i>ed with tho itnpinger w the opening of the *inlo llu*. paper thim0 the expansion rom1 the snclion device; 29 Iho Jailer, be it an ejector, electrically driven blower, or foot pump, is provided with a metering device for measuring the air flow, which is usually maintained at lh(- rate of 2 cubic feet per minute. Before using a thimble it must lx dried to a constant weight. This may bo accomplished by one of two ways. First; thimbles can bo given a preliminary drying at 90 to fl' C. for 3 to 7 days in an ordinary drying oven, and then just before using they arc dried in a vacuum oven for 7 hours nt 90 C. and weighed. To obtain n cheek weight tiny tire exposed overnight to room air aud again dried in vacuum for 7 hours. After sampling, the same 7-hour vacuum drying period is employed. Second, tbo thimbles which have had the pre liminary treatment may be dried just- before use in nn ordinary hot-air oven for two days r.t 90 to 95 C. This period is sufficient to bring them to constant weight with no check drying being necessary in this instance. After sampling the same 2-day drying period .is followed. Two blank thimbles, not used in tbo collection of dust, ore dried, and weighed according to one of tho two methods outlined, vhich enables one to check tbo conshtncy of tbo thimble weights during the drying perioil. Tho thimbles are placed in a special glass weighing container after removal from tho ovcu nnd are allowed to cool in a dessicator. A counterpoise weighing bottle is placed on the pan of the baluneo opposite to tho one containing the thimble, thus compensating for moisture condensation on the somewhat large surfaces of the bottles. Tho thimble nnd bottle are weighed rapidly io the nearest milligram aud then the empty bottle is weighed. The difference in weight represents tho dry weight of the thimble. After a sample of dust is collected tbo thimble is placed in tho drying oren and brought to constant weight, as described. The increase iu weight of tho thimble is tho dry weight of the eullccted dust. This weight is divided by tho volume of air sampled, yielding a weight per unit volume, such as milligrams per cubic fool, etc. EJUdeacy of thimbles * Tests on the filtering efficiency of the paper thimble were conducted by Trustcl and Frerert on various dusts of different sixes. These tests showed that the devieu recovered nearly 100 percent of tho dust sampled. Against tobacco smoke of a 0.27 micron mo the thimble dcvico was found by nptiral methods to. bo 46 percent efficient. *Vpmi!tt silica dust of a>ixc from 1 to 2 microns (average industrial. so of dust), the optical method showed 100 percent efficiency after tt7 seconds of sampling had elapsed. Again, gravimetric tests will* very finely divided eoroslarvh showed this instrument to practically H)0 percent effective in collecting dust. It iiiigiit. lie expected that since pajuv is highly hygroscopic that lh mt*s of air How through thimbles would be different in ntmos- 1$ DOCUMENT WAS NOT A RECORD OF G INDUSTRIES, INC. DID NOT COME FROM S FILES AND CANNOT BE AUTHENTICATED ' PPG INDUSTRIES, INC. 1J3B Q0J9995 J 2489 30 In inmn-tt ilm r>*sUi;u<`n llimtiirit the thimble, thereby derreasiir* the rule of air flow and vitiating the volume readings on llie metering device. In order to test llic effect of humidity on the thimbles, tests were rondticUd :it Jo, 50,75, end 00 percent hnmidflim for n total period of 7 days. The thimbles were first dried U constant weight and the rate of nir flow* determined. Then tlio 7-<lay test on tho thimbles was made nuiil their regain in weight \vn* constant, when the rata of air flow was spun determined. It was found that the rate of air flow over the range of relative humidities tested was not afleeted, even at the highly saturated condition of 90 percent. The iippli.'alit;u o! this device to industrial dust Rumpling will he discussed jnoro fully in the portion of this section dealing with tho various ad van tail's and disadvantages of the instruments covered in this discussion. THIS KO.NJ1SETCT of South Africa. Thu typo of I onimcler most frequently used in this country is the one employing a circular glass plate wiucli is revolved to produce n ring of dust spots near tho periphery. t, r. v- Dncrlpliun of Instrument Tlie circular type of konimcler is depicted in figure 34. It consists cssentialiy of a vnlveless cylindrical suction pump and a dial of brass; (ho pistou of tho pump i* actuated hy n rpring which insures uniform operation. About 10 cc of air are sampled per strobe,, tho exact amount being detenuiued by calibration of the instrument. This may bo accomplished bv attaching the auction side of tho device to a ' graduated gas burette containing water and noting the amount of water displaced. Tho dial chamber contains a circular glass jdatc, resting on a hard-rublaT ring so arranged that the air from tho stirrounding atmosphere is drawn, upon releasing the piston, through a nozzle 0.0235 inch (0.57 mm) in diameter and is impinged upon the plate, located 0.0197 inch (0.5 mm) from the end of tho nozzle. For the purpose of retaining the dust- effectively, a tliin film of fictrolatum is usually smeared on the glass phi tc. The glass plate is attached to a toothed brass ring, which engage* a pinion operated on a rod extending outside tho instrument. The glass is revolved to expose fresh surfaces os needed. Tho hisin.incnt is provided with 29 sectors on the ring, i: each one numlH'n*d so ns to record each dust spot or sample. ~ The koniiueicr is compart, simple to operate, is only 0'A inches long, and wciglis but 22} pounds. * ` f [ < ; 1 BB 0019996 J i 2490 r- trim, would li-uil i^^lbcrrby (i'irri.'.iii^ readings on tbo litrirriir' ty on I ho durables, list s it humidities for a total dried to constant weight n the 7-day test on the ight was constant, when t was found that the min nudities tested was nut, ion of >0 percent, ial dust sampling will lie section dealing with tho c instruments coveted in dust by impinging air plate, was developed by ?is Prevention Commit tro st frequently used in this s phito which is revolved iphm*. I ir to 14. It consists pu^^ ,<nd a dial of brass; u^HtrU insures uniform confer stroke, the exact lie instrument. This may side of tho device to a id noting the amount of ins a circular glass plate, dial tho air from tho sirr ing tho piston, through a wd is impinged upon tho to end of tlio nozzle. For , a thin film of petrolatum rlass plate is attached to u` icri ted on a rod extending ;d to exjjoso fresh surfaces th 29 sectors on tho ring, sjiot nr sample, t tc, is uuly C}a indies long. 31 Mi-:lusl of c Prior to old .'lining samples of aerial dust vritU the Unnuneter it should 1st carefully cleaned and prepared for use. Tho orilieu of the mi/zlo tuny he cleaned with a horsehair or other suitiildo material and the volume of tho device is determined from time to time in the man ner already nieuliom.il. Tho glass plate is covered thinly with filtered fu'lroiatmu, lv rubbing evenly over the pinto with a clean glass stirring rod containing a quantity of petrolatum about the sue of a pinhead. The parts of the instrument are then assembled and the nid operating the pinion which engages the toothed brass ring and gbit* plate is so moved as to expose sector no. 1 opposite the nozzle. To obtain a sample of dust the piston is pushed inward until it is nuight and held in place by a locking pin provided for that purpose. The orifice at the hack of the koiumctur is field at the sampling point iul a Sample is procured by. pressing the trigger which releases the nring. Air rushes in ilirough 1 he nozzle at a high velocity impinging fMihist content in tho petrolatum film on the glass plate. To obtain Anotlw-r sample the pinion is turned to bring the next S4*etnr info |**siih*n. Tho method of examining tho dust samples will Iks treated ,M Hie next section wliich deals with this subject. c. c\. r' F"' - U h" *" ' OC THIS DOCUMENT WAS NOT A RECOI PPG INDUSTRIES, INC. DID NOT COME jT'S FILES AND CANNOT BE AUTHENTII pY PPG INDUSTRIES, INC. i 2491 32 Tho etiicienrv of the W.umctrr, when sampling in moderately dusty atmospheres, ha* Won louml to be about 1.5 limca that, of (he impingcr drvh-e, both in laboratory tests and in comparative studies conducted in tin: field lender practical operation (25) (24). OWEN'S JET OUST COCNTJCU Principle of Instrument Thcjel dtist counter was devised by Dr. Owens, of London, ling-land, for the study of atmospheric rmokein connection with the work of the .Advisory Committee on Atmospheric Pollution. The principle of tliis apparatus is very similar to the konbucler. The device depends - for its action on the principle that '"** when air containing dust passes through a narrow orifice facing a gloss surface a short distaiico away from the jet, tlie dust trill adhere to tlie gloss. In the Owens instru* ^ ment this result is acluevcd hy causing a very fine, riblion-sUaped ^ jet of air to strike a microscope ^ cover glass situated about 1 ir.m ^ from a slot-shaped opening forming - tlie jet. The air, before entering ): the slot, is passed tltrough a damp- '/ ingchambcr, and tlie velocity in the 7 jet is such that a fall of pressure ,, results, in this way bringing about a condensation of moisture. Tlie air 1"' lIRtt U--Or tax Jt dart nwnttf mmsLM fur urn. is then deflected and the dust, be- L' ing unablo to turn the corner, y strikes the cover gloss; tho velocity of the air drops,tlie pressure and temperature rise, causing tlie water to be evapornted anU to leavo the 2 dust behind. Description of instrument Figure 15 sliows tlie instrumentinits assembled fonn whilo figure 1C depicts the essential jiortiuns of Uie dovico in more detail. Tho appar atus shown in figure XG consists of a brass sleeve B open at tho top and bottom and screwed internally for tlie reception of the part JC. This part (ft)is perforated by ncctilral'liulofor admitting the air to a narrow dot formed diametrically across tho hole by means of two semicircular metallic plait*, held in position by a ring It attached to the plug K. Into the upper opening of the sleeve B is fitted a screwed plug O, provided with an aMaeliinout consisting of n spindle L which pene Irate* the alcove formed in the plug C and ciuls at tho outer end in a Tjb 0019998 1 This document was not a recoro-of PPG INDUSTRIE^. INC. DID NOT COME FROM IT'S FILES. AND CANNOT BE AUTHENTICATED 0Y PPG INDUSTRIES, INC. r n sampling in moderately alwuit 1.5 (i/ii'M dial t>\ t!e and in comparative .-Indies ration (2:]) (24). mvTEJl Owen*, or London, Eng'.tud, .section with the work of the 'ollution. The principle of jaictcr. The device dip-nds action on the principle (h.'.t air containing dust passes A a narrow orifice faring a surface a short distance away itc jet, the dust will adhere glass. In the Owens itislruthis* res^ilt is achieved by g a very fine, ribbon-$hai>ed air to strike a microscope glass situated about 1 mm flot-tdiaped opening forming L \ air, before entering j^^,ased through a damp.uSrc,and the velocity in the such that a fall of pressure s,in this way bringing about a :nsatioucf moisture. The air :n dcllcrtcd and the dust, bo.mablo to torn the comer, he air drops, the pressure and jc evaporated and to lenvo the iswmblcd form wiiilc figure 1C :o in more detail. The cppnr.s sleeve U open at tlu- top ud eccptiou of th part K._ This radntilting Ihcainon narrow * by means of two semicircular :jg It attached to the phig K. IS is lilted a srr`Wetl plug O, :g of a spindle L which peun uinl ends at tho outer end in a 33 knurled head .T, and a t the other end in a carrier plate O. This carrier plate receives iho cover glass and has two stops on its wlgo to aid in mitering it. A flat spring 1* is fixed above the plate 0 v/itli its cuds bent round so ns to hold ilio cover glass finnlv against tho plate 0 when tho glass is in jMwdliaii. A spiral spring M, located between tho plate O and the plug C, keeps tho cover glass pressed downward over tho slot of the instrument when the plug C is screwed into place. To insert the cover glass on the carrier plato O tho plug C with its attachments h held in nr-.o hand and the knurled head J withdrawn suffi ciently to press the spring P against the plug C, thereby lift ing the bent ends of the spring P from tho plato O, allowing a cover glass to be in serted. AYhcn tho knurled head J is re leaseditisdrawn back by the spring M, the comh spring P comes out of contact with the {dug C and the bent ends press down on the cover glass, thus Km mmiiwC tlmO mew it--i>oiiafafOM>MSitftMaur. * holding it tightly in place. "When the plug C is screwed into ]>osition in tho instrument (in the sleeve B), tho stop* upon plato O make contact with the ring K which forms the cell around Iho slot. Tho distance of tho cover {riuMi from the slot is thus fixed and the cover glass may bo ro tated to any position by means of the knurled head J. Tito washer II makes nn air-tight joint between tho'plug C and tho *WvoB. inside t he sleeve B andsiirrnunding tho covergluss is au on* '"(l.iriwvswhich communicate*with a connection E for attachment to "u nir pump of fiO cc capacity. A damping chamber T is furnished, * hieli xs dctachahio from t ho plug IC by unscrewing. This chamber is fined with blotting pt>cr which is wetted prior to using tho instrument. MriUmJ r operation Prior to sampling one should make sum tliat tho slot is dear of any oh.iruetion. It may ho cleaned by means of a slip of thin ]wiper U&BOO O fO f O OCUMENT WAS NOT A RECORD Of DUSTRIES, INC. DID HOT COME FROM .S AND CANNOT'BE AUTHE :TCA <.> 3 INDUSTR'ES INC 2493 pushed through from below. The air pump should ho tested for leak age from time to time. This is accomplished by holding a moistened Huger over tho opening, drawing out tlio plunger smartly, holding it a few seconds, then letting it go, when it should return to tho bottom of the pump. If the plunger does not return it may be necessary to grease it slightly with vaseline or renew tho valve. To obtain a dust record tho pump is fixed to the connection J3, ami before tho plug C is removed three or four strokes of tlio pump are made in order to fill the damping chamber with tho air to be tested, leaving the pump plunger pushed in all tho way. Tlio blotting paper in tho damping chamlwr should bo wetted before sampling is started. Tho plug C is rapidly removed and a carefully cleaned cover glass is inserted upon the ring Jt, after which the plug C is quickly replaced and screwed in tightly. The pump plunger is then pulled out smartly so as to drew in 50 ce of air through the jet. If more air is desired tho pluugcr can be operated again after allowing an interval of 15 or 20 seconds to elapse in order to allow tho air to C~` ' absorb moisture from the damping chamber. Tho plug C is then ; removed, the cover glass dropped out on the hand, when it is ready for mounting. The dust record is mounted on thin, tin rings cemented onto a microscope slide. Several such slides arc previously prepared for this purpose. This may be done by placing a few drops of the cement, which accompanies the instrument, onto the slide and placing a tin ring onto the glass, squeezing gently down on the ring. The dust record is mounted dry, face down, so that oil immersion may be used in examining tho record. To mount the coverslip one merely places three small droj>s of the cement onto the tin ring and then places tho coverslip gently on it, pressing Sown so as to allow the cement to flow around the ring and complete the scab Two rings maybe placed on one slide if one so desires. "When ono is finished with an examination of a record, tlio coverslips, rings, and slides may bo salvaged for further uso by placing them in a dish of water, thus loosening the coverslip and ring from the glass. After proper dean* -- ing these objects may bo used again. * amnuitv An attempt lias been made to deserilxj the most frequently used instruments employed in dust sampling at the present time, in such a manner that very little difficulty should bo experienced in operating tho five instruments discussed in this chapter. Illustrations of the instruments, their principle of operation, calibration, and method of sampling have been given in some detail.* In the following table (table. 7), a summary of some of the characteristics of these instru* incuts is given. It may he seen that all of tho devices have a high sampling efficiency. Although cavil instrument bus some disud* | BB 0020000 | ; .I f cl bo tested for loakhuhiing a moistened smartly, holding it. oturu to tlio bottom my bo necvssury to 0 connection IS, urn! es of the pump arc with the air to be way. Tbs blotting 1 before sampling is a carefully cleaned -Inch the plus1 C is itnp plunder is tlien through the jot. if again after Allowing * to allow the air to rbc plug C is then id, wlien it is ready ;s cemented onto a ionsly prepared for dre' of the ccmenl, io . daring a tin The rinst jcSto may be used p one merely places and then places the .How the cement to Two rings maybe is finished with an and slides may be iisli of water, thus After proper dean* ost frequently used resent time, in such wneed in operating lllustratums of the thin, ami method f the following table ties of these insinidevtres have tt high t has some disad* vantages, experience has shown (hat (here is a sjiccific use for each device. The inipinger apparatus, which is (he one used most uni versally, lmth in this counliy and abroad, cun I>c employed for sam pling in both high and low dust concent rations, and 1ms (be added advantage that the sum pies may be analyzed uiicroscopirolly, dicmically or gmvimetricull.v. In fact, it lias also proved useful for sam pling fumes and gases, provided certain precautions nre exercised (*Jfi) (20). Tlic electrical precipitator is not used very frequently for dusts, finding its greatest field in the sampling of smoko and fumes. The p;ij>er tbimbb* ha.- b*:en used for the sampling of radioactivo dusts very successfully and U constantly employed in sampling organic dusts in connection with dust explosion prevention work. The Owens dot Dust Counter, was primarily developed for tho sampling of outdoor dusts and smoke and is still used for this purpose quite universally. It is not practical for tho sampling of industrial dusts of high concentration, tho dust record being so thick ns to make it impossible of enumeration. However, it has been used successfully for obtaining samples of industrial dusts for the purpose of particlesize measurements. This use will be dm It with 'in more detail in section IV. The konimetcr is very useful in obtaining rapid samples in moderate concentrations of aerial dusts. For quantities of Id to IS million particles or less per cubic foot of air it is very efficient and should find considerable use in control work and in preliminary studies. For such investigations the Owens and konimetcr have the added advantage that they require no power for operation, arc very small and compact and do not need a highly skilled observer to obtain samples, although some skill is required iu the enumeration of the dust records mid in the interpretation of results. So far this discussion has hcen limited to tlic collection of dusts of the type capable of producing fibroids of the lungs or upper respiratory damage. For the collection of poisonous dusts, such as lead, tho inipinger or electrical precipitator luire been found to bo best suited for this purpose. The paper thimble lias been used successfully for the collection of radioactive dusts, but on the whole the impingcr and precipitator collect such dusts in a manner best suited for the sub sequent chemical analysis. In the case of the impingcr when used in xnutpfing lead dusts, care should tie taken that tlic sampling flask is of load-free glass and that the distilled water also contains no traces f (his compound. It is customary to nm a blank for every 10 samples or so,jvhicit times into account any lead present in the reagents. In sampling for minute truces of poisonous compounds, it is very essential hat Kulfieirnlly largo samples lie obtained, enough to contain ndeM'lato amounts of the material for the particular method of analysis to 1*1 employed. It is apparent that both the inipinger and electrical pnvipitator fulfill this requirement- owing to their high uir samplingpr o to -- :.'l C. i j 1--- : r "o L< -j p-- O V THIS DOCUMENT WAS NOT A RECORt PPG INDUSTRIES, INC. DtO NOT COME F IT'S FILES AND CANNOT BE AUTHENTIC* BY PPG INDUSTRIES, INC. I 2235 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM rrs FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC.. * Taiiui 7.---.Summitry / chnrnchritllo of crrluin ilwal-Aamjiltng imtrnmcuU L'hnmrinbltr* iMlmmwit M*ortlsn Kdlcteney ntHln'l bnluslrbl dud* l|ttnu() AtifiOcMlIii* MdM of liKUlUftfwIk* (HOI U >inNiirt- iulk.n finwidni dull Volume at Kllll|la Adeonleceiii-f Inriiimienl I>l*lratilitr** at Inilnmirui lM|-h:*er........... lm|4etMral.. *+...... (IrtMvn]........... ('mill, rravh m 1 r 1 r, I'H.hlrt- thane.... . .loir MmHil! nta-lllll-tr 1. Ilhth rnm|>l!nc efllrimrir In i Lllnr lut ie litrh 1. Ilr>hruimlre. t iioirti bruin** riwulcaL dn-i nimili:i'.t U 1 Hjiui m i-jii l iiiiiiiint-.iii-t Uy vnni'.tic, v> (thing, cr chemknl nia'yaii. lilnttM |ir*- Kircitleattr* in........ clrililar. d|>11ribM. (`nnthlrr* An|T nmattM: 1. Itfeh rim|4Jn* AllHnHT 1. He*ttibet cirrirb raver hie. Wlt to III |*iw w I1i4.fi Ac u|<rrikin. * f-9 llltnt n dihi HHei|trr.ll'4tL 1. fame ileutrr Irani high mtoml*. 1 ftti*i|J4 enn Ik# i|ii:iiiil!t> hlbM r.i'id l)r t-rtmliny. tttMtlng, or f.-K'inluJ npiiii.si1. X Ltifu obLitnviS tU'i'iir. 1*| tr Ifaimlile... rtlUolk*....... ten........ OntliMl rlr. l<Mn_. Vcnrlllllr. Any wiipmii: 1. llUtorttiil'hneetArlrtirr.. I. Sampler cannot bt chemhr.lL toll IMS 1 hnnn>'*c Liico Volume1 Mln:i<|. nil-le feet jet (:<|4'lly. 1 Dtyl:n! w Ihhnhlei h Minnie, 1, l.ilin,lur>- li-Htiile it. Very tlntr iimhi Iiikn rnly drytnjt anil 'h hint!hr!.! ikltlj. A. Minii|4prT limy he le,'t In- |.-i.i,l:.'ly* without ,le- IrlinllM. Oven* fet duel Jtt cwmIwm* DaMtn 4wt CcdlcCM. nil 1.000 er. 1. l-hrtil. dvide, tind uuk-k t. Purl cannot he welched ewioltr. IWm. mm bt |rtt- In llI.H., or antlritd tbccih rie-nbn 1im> be. 1 lltrtie'I.rkrnryhrnlttHw. tnllr. I'trtfip (unit. t Ohiohit *nly "rnli" 1-- 1 1 Kn tm iMiw-lcd hr mvrmk.i. ciinj-l,-* due lo email fHiiijdliit ruktnie. M 1. IjlMM itcy trehale re- A Iiu|im :Ii-iI In high dtul intow imly inkru- tuuiefilfHlkmf. 1"! 1aI Htn**. i. Mcrltetiibn:cJllcknl mi!)' I r du.la I mh Aunrorlerw CO Cl ii i to i it l- i 40 i * ip' MS'S* r0 mSO >c Z3I o> ^3 2Z < 20$ * 3ow ; BO2 t nwO * 2 -t ', Otworunttltt. Imi tottioa. * t i uul<lf <* rjc^Ar* *u+ ....lo ll l 1,W W. tlsifhtr1 l`> > 4, fUeii'ht limit lie he;<t l. MiMi' without i|t- t<vturiilfc<*. I. l-litnhlt,i-nImtlir.,lt, owl IIIt It h wjrW otilii**I'fl-.ll-EJlIoi.*. 9. K|<mt >nv,tt) hitti)T' mint. 4. I.ilwuiinj tochnls it' .intro* tmljr I Mint- >W|1. |M( twwrol !< vright4 M iiwIfiH thenth nitty. 1. UM.1K1* only "ft**" itim lo tut t|| ruii|<lio \i4iur. I. Imi'iH'l.'r .l.'n huh dull nmrrNMMt. 4. fthi llir wth'ji:tWeVut tilr t"4 divU I ml* tOHtl ut ItM. 03 \ III. Tin: 11HAN'T!KICAT1QN Of INDUSTRIAL DUSTS rxKUMocoNioaKS-i'Konucixo dusts General cciiluraUotig Tlio method of quantification used on llic samples of aerial dust collected hy the various instruments dciwribcd in the previous section will lie governed largely by the fact that our interest in the dustprob- 1cm is primarily a, hygienic one. In the owo of fihroris-produt-ing dusts it has been found that tho particle count offers the best index of tho hnsardousner's of A dusty ojHmtioii, especially in extensive studies of the problem dealing with the health of workers in dusty trades. Obviously, tho method of enumeration which is utilised should ho governed hy the consideration of the sue of the dust which is of hygienic significance. To date, tho relative significance of various sixes of dust put tides in tho production of lung fibrosis lias not Ix-cn satisfactorily established. However, wo do know that the initiation of certain industrial dusts 1ms been found to be assodated with definito iujuty to tho pulmonary tissues, lienee, a knowledge ' of the size frequency of these industrial dusts will in a measure do- temiino the metliod of enumeration to be employed in order to --~ >r cvnlunto the imluairial dust liazi rd. At present there are several sources of information which east }-- some light on this subject. One is tho work of pathologists, who havo determined the size of dust particles recovered from silicotic b lung tissue; another source Is the work done in connection with the . retention of dusts, while additional information is presented by parti- cle-tuzo studies which have l.*oen inado on industrial dusts. Moir (27), IVatkins-l'itehford (2$), and Mavrogordato (23), of Soutli Africa, havo shown that most of the dust particles recovered by them from both human and animal silicotic lungs were between 1 and 3 microns in size. Only 13 percent of tbo particles were found to bo less tlrnn 0.5 micron. Thcso results are somewhat similar to j those obtained by Schcid of Germany (30). Drinker, in comparing . tlio sizo frequency of the purtirlcs measured by Moir with the par* r` tides found by him in the sputum, of men employed in ore mills, j^ found a. very close comspondctico (31). Decent experiments by zf' iz!L lung and Dolmi (32) on the metabolism of silica iudieale tliat ex- trerody fine ]>arlirIos of quartz, those less than 3 microns in size, aro rapidly dissolved in tho mildly alkaline body fluids, nnd are excreted in tbo urine. Tlio results of these findings raise two very pertinent questions; namely, (1) to wlmt extent are minuto particles of dust retained hy (he hunmu lungs, and (2) do npprrciablo per- geentapes of industrial dusts ever fragment into those minuto sizes less than 0.5 mimm? i t : l> rI hr I in `Ml in.-. `Ira ft | l. U |r*| til .1 L<uil U*H ti tin* ! UI..I i: I ** l-ll. i C3S) THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, !NC. DID NOt COME FROM |T'S FILES AND CANNOT 8 AUTHENTICATED Y PPG INDUSTRIES, INC. 1 BB 0020004 | 1 _____ ' 2498 DUSTS 2 OVulS :c Samples of aerial dn-t ti in the previous sceiinu interest in the dust prol*. -isP of fihru-'.i$-pn ;!11eiig ant offeis the best index , especially in extensive .ith of workers in dust y ration wliieli is utilized tie size of the dust whir!-, relative significance of tion f lung fibrosis has it, wo do know that the n found lo bo associated s. lienee, a Jcnowledgn ts will in a measure de; employed in order to informal ion which cast rk ' pathologists, who re red from rilieotie i i^^mieerion with the o^Bnwnied by porii- lusSnal dusts. MaTrogordato (2y), of dust particles recovered otic lungs were between the particles wore found iro somewhat siniQur to Drinker, in comparing i by Moir with tho par- employed in re mills, Beccnfc experiments by ' silica iudicalo tluit cxthan 3 microns in size,. `O body fluids, and an* findings raise two very out are minute partirli* (2) do appreciable jvririlo these minute sizes 39 The woik of Drinker (33) and his associates, and that ot Drown (34) on the retention <r certain dusts nml fumes bv man when known unwinds were breathed, seem to indicate tluit the coarser suspensions were retained more effectively than tho more finely divided materials. Percentage retention was found to be directly proportional to par ticulate sice and to the density of tho dust suspension in tho nir. Sayers and his colleagues (35), in a study of tho health hazards asso ciated with tho use of tetraethyl lead gasoline, found that fine par ticulate matter such as tho lead dust from automobile exhaust gas urin" dby! gasoline was retained to an average extent of only 15 percent of tho amount inhaled. Shaw and Owens, upon measuring tlie amount of dust i:i expired air of London inhabitants, found that <.;:!y 25 p^rceat- of the dust was retained (30). Tho average size of the dust, inhaled iu their experiments was about 0.5 micron. This work on dust retention seems to indicate that dust particles of a sizo less than 0.5 micron play but a small role in the problem of in dustrial dust inhalation, and in a manner furnishes an answer to the question raised earlier in tliis discussion; namely, the extent to which mhiiitc particles of dust are retained by human beings. The answer to the second question--that is, the ability of tho ordi nary industrial process tu fragment appreciable quantities of dust to a mo less than 0.5 micron--is partially answered by a particle-size study f tho dusts actually suspended in industrial atmospheres. Surh a study made by tho authors in the course of their numerous investigations in dusty industries reveals tho fact that practically all >f tho dust particle* examined by them (more than 10,000 particles in about 50 samples) are between 1 and 3 microns in size, nlxuit 70 percent of tho dust particles lying in this range. Only about 20 per mit of the pnrtidc3 were found to bo less than 1 micron, the average median sizo being 1.3. Although no two dusts were found to irnvo exactly the snmo size frequency, differing at. times for tho samo dust miaied by different operations, it was found that for nil practical purposes tho dust particles fall into very narrow limits, tho majority living between 1 and 3 microns (37). From the foregoing information it is evident that in order to obtain a representative sample of industrial dustin air, one should employ an instrument capable c>f arresting with a high degree of efficiency all Linds of dusts, of sizes ranging from 0.5 to 5 microns nt both high- and, Ltw-tlust concentrations. The instruments dcscrilxxl in the previous hnptiT fulfill tlti* requirement. Zn addition; the method of counting '*' dust particles in the samples should hdvo small analytical errors itwl should reveal only those significant particles present in industrial "lunsphercs. It should not he the aim to count all tho dust particles ;* i*`,nt in the satuples (which may Ihj accomplished by either the use of :h magnifications, dark-field illmiuiuiliou, or combinations of both), NT DID cy c.: C C'J t-- I_B8 0020005*7 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES,* INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. j 9 * QQ *w*sioa 40 sineo it is necessary to differentiate between tbo dust content in norma! air and industrial air. As has been just indicated, this dif ference is sharply marked insofar as the dust particles between 0.5 and 5 microns are concerned; hut tins difference would be masked and lost should wo ineludo in our determination the particles of ultraiuicroscopic size which arc present in vast numbers in all air. Tho method of dust counting to ho descrilxxi in the following pages fulfills tho requirements set .forth in iho present discussion with reference to industrial dusts. As a proof of tho vulue of tho method of dust counting to bo presented, high correlations have been obtained between counts in various industries and the degree of silicosis and tuberculosis among llio workers exposed to tho dusts investigated (2). It is obvious, therefore, that the technic of dust analysis which is now being used extensively in this country and which is described in tbo pages to follow, constitutes a valuahlo index of the hazardousucss of dust iubnlation. Qcaulliication of im;>lnger samples Counting in (!*.--Earlier in tliis bulletin it wus pointed out that practically all dusts are, to sonic extent, soluble in water and, hence, counts should be conducted within 24 hours after sampling. Such a pmctico tends to prevent any undue flocculation os well as solvent action on some of the minute dust particles. C~ As soon, therefore, as tho samples con be transferred to a satis- { ,,. factory place for counting, tho stopper of the Cask is removed and ;' carefully washed, the washings being added to the contents of tho i flask. Next tho cutiro sample may bo filtered into a previously ' cleaned graduated flask through a screen of appropriate fineness - (325 luesh) so tbut only particles smaller than 40 microns in diameter ; uro permitted to pass through. If the dust suspension in tbo gradu- ; ated flask is too dense, further dilution is advisable. Tliis dilution ; may conveniently be such that tho number of particles counted in each microscope field is about 50 to 75. Tho contents of tho gradu- . ated flask am next thoroughly agitated in order to obtain a uniform " suspension, and two portions of about I cubic centimeter each arc . ,, .. removed with a pipette so as to just fill, without bubbles, two Sedg- wick-Ilsftcr counting cells (sec fig. 17). The cells havo been pro- viously cleaned very carefully in order to remove any adventitious hrj dust, and have been kept protected from dust particles by tho cover slip. In making dust counts an eyepieco micrometer known ns a "TTkii>- ple disk" is employed. (Sea fig. 17.) Tliis disk has a large square engraved on it, covering a largo part of tho field, and tliis squaro is ~ divided into 100 medium-sized squares, 1 of tbeso in turn being Jhfurther subdivided into 25 very small squares. Using an ordinary ' microscope provided with a suitublo eyepiece and objective and fitted OWuAsSe NNOUTi A RECOcRcDroOMf 2500 en the dust content in just indicated, lids difnartieles between 0.5 uiul ~ou!d he masked and loft particles of ullraimero3 in all nir. ed in the foliowing: past.* present disem-ion with no value of the method cf :ious have been obtained -jC degree of silicosis and tie dusts investigated id), ust analysis which is now which is described in the t of tho liazordousncss of a it was pointed out that able in water and, hence, s after sampling. Such a da as well as solvent bg^o.*ferred to a sntisis removed and ,-d to the contents of tho Altered into a previously i of appropriate fineness an 40 microns in diameter : suspension in tho gradu* advisable. This dilution *r f particles counted in he contents of tho gradujrder to obtain a uniform ubic centimeter each nro .Ihout hubbies, two SedgTho cells hare lieen preremove any adventitious lust particles by tho cover meter known as a "`Wliiivus dr-U has si largo square to field, and tills sipiaro is 1 of lluv-o in turn being uares. Using an ordinary co and objective ami fitted 41 with an Abbe condenser, the proper tubo length of tho microscope is determined by calibration with a stage micrometer, so that the side of tho largo square of tho eyepiece covors 1,000 microtis (1 mm). (A 7.aX eyepiece, JG nun objective, and a tubo length of 178 mm has iieen found to yield this result.) Tho largo square of tho eyepiece ruling, therefore, encloses tho dust in on area of 1 square millimeter; and since tho red is 1 millimeter deep, all tho dust suspended in 1 rtibic millimeter of tho water is under tlm ruled field. This examina tion is accomplished by raising nud lowering the lens system so ns to focus throughout tho entire depth of the cclL As a source of illumi nation ni' ordinary small electric microscope lamp may bo employed. In order to provide a high degree of visibility for retractile objects it U best to lower the Abbo condenser system below tho usual focusing point and to restrict tho opening in the iris diaphragm. Tho dust is allowed to settle for 20 minutes before counting is dono. In general, only particles less than 10 microns in diameter are counted. Tho inclusion of particles larger than 1C microns in tho filtered speci- horn* li^MHO'ltslKt rauitif oil sad Whip^l* color otknnMttr Sit men would mnko but little chango in the total count. Tito average diameter of a porticlo for the purpose of litis exclusion is judged by inspection. In practice it is necessary to count tlio dust in only onequarter of each ruled field, the entire field haring been examined, for uniformity. Such counts on 5 fields, so dispersed ns to bo represent ative, ere made on each of (he 2 Sedgwick-Rafter cells. Theso 10 counts are averaged, but this avcrzigo is not to be taken as tho final count until a corresponding control count lias been subtracted. In t eases a sampling flask which Is handled in tho plant, hut through Me!i no air has Iron aspirated, is used as tho control for tho par ticular series of samples taken in that plant on that particular day, ml counts are mado on this control fluid in the samo manner as on il' fluid through which the air sample lias hden impinged. Tho conlr,d sample takes into consideration auy dust which may bo present *** tho eyepiece micrometer, in tho lenses of tho microscope, in tho ^dgwick-Uaff or counting cell,Pnd in tho saniplingfiuid itself. From average ginss count obtained on tho impingcr sample, tho average utrol count is to bo subtracted to givo tho average not count per uiieni-Mrupic field. --- cO t tit 1 THIS DOCUMENT WAS NOT A RECORD OF* PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. t4 1i | BB 00 :o< 2501 42 The average net. count per )f-iuirnKco|m; field is multiplied by 4 to yield the average couiit in the total licit]. Siiu-o the Scdgwick-ltafU-r cell is 1 millimeter dorp, this figure represents the number of purtides in n cubic millimeter of tho diluted sample. This vnluo is mul tiplied by 1,000 to give the count }*-.r cubic ceutiincter of sample and again. by (he totul number of cubic centimeters of fluid to which (ho original sjeeinion \vs diluted. Tliis product is divided by tho mini, ber of cubic feet of air sampled. In summary, tho number of par ticles per cubic foot of tucavcn>go net count per }i field times a factor, where tho factor 4X1/H10Xtold volume of diluted sample in rubic centimeters Volume of uir sampled in cubic feet Tho record should show tho sample number, date, sampling loca tion, nml volumo of oir in cubic feet. Tho steps in counting should bo recorded ns to date, volumo of fluid, volumo taken for dilution, calculated total volumo at fiual dilution, average gross count per } microscopic field, average control count, averago net count, factor according to abovo formula, and finally number of particles expressed in millions per cubic foot, together witli any additional notes. Table S, which foltows, shows some typical dust counts obtained with the impinger apparatus in tho various industries listed. Tabu: S.--Atcrage dust count in tertain dusty trade* Alla (lnWilna mill*! TSeniuns Tala tuti-hin? mllli: Omaha merr} lag: tittaifomtint: ABUimrita cwtl ciinitc: mamlwB (ml ftuauw: SOvftvuM nuitvi;<9E: . Micnr*|*l tlM Cnlian lo-Unary: IwlwUT Ixm (wit la tnillHNrt cuUnhmst Ait UM.I J2T&0 3121 imi 4iS M. Ml **.t HI IIU nat XI m HI BL* ILl 1C.J U Lt Ll 4.1 Li 11 4.1 \ l! (' I 1, I. nin ;*l3 j BB 0020008 [ 2502 5 multiplied by 4 ho Sedgwick-llnfIir .he mmd>or of par- Thu vultto is nittlmeter of sample ami *.f fluid to which the divided by tho nu::thc number of parper }i field times a rubic contlmeters Xcct " " date, sampling loc.-t* s ia counting should a titUca for dilution, ,*e gross count per JJ50 net count, factor of particles expressed iitionnl notes, du ounls obtained ist listed. UOM (Wilt ta mWiieiaf |wtlrir(|*r cubit L*** tit 1XK0 XSat tti.% SULK ( aiAUaa.sI1 iuac*.t41 AS sUx.j0* SSL* 3J.1 ie.3 a &: Ll iLlS Li 43 (Iraeimetric auohjxix uj impinger mmpie*.--Tho weight of tho dust sampled by I ho impinger may he determined in 1 of 2 ways. The juimt-eopic analysis consumes but a very small amount of tho sample, at times ns litllo as 2 cc. The remaining port ion of the sample may be evaporated to dryness in a platinum or other suitable did) ami weighed- on an analytical balance. This weight (subtracting the weight of the empty dl-di) will yield the total weight of tho sample and dividing by the number of cubic feet sampled will give the total weight per unit volume, correction being made for the dust contained in the volume of water used in tho microscopic analysis. To deter mine, the amount of orgnuic and inorganic matter present in tho sample, the dust in the container is ignited in a inutile furnace. Tho new weight is the inorganic matter present, while subtracting this weight from the total gives the amount of organic matter in the sample. An alternative method of gravimetric analysis consists of filtering the portion of tho sample not used microscopically through an ignited and weighed Gooch crucible, drying the crucible in an oven at 105* C. for 4 hours or more, and weighing again. The crueiblo may then las ignited in a mnfilc furnace if it is desired to determine the percent age of organic and inorganic matter. In all analyst1*, regardless of the method used, control weights ere necessary on the distilled water itself for eveiy set of 10 or more samples. During the condurt of various dust studies both weights aud counts have been obtained on the du& samples collected by tho impinger apparatus. Tho following tnbio shows the correlations between counts end weights on the various dusts investigated: Tamm 9.---Correlation bchea* particle count3 and vciqht* of iiuiutirial dutit in air MstoH*............ All<h*n .......... Du* * - " - Kaiiampihwi ColitwwuOtWWnM- Xdlilmttialunra*f Sn*mCi&vstf^uMiUraht . . . ..... . . .... . ... .. . __-__-__.._._____ . ......_.._._ 31t4$3u*o4000 .**.TA7v03MMMn1 334Wts111 to 11 may bo seen from the results of tho above tabic that liigh corrvln)Uw exist between counts and weights. However, it has been tho moral experienro that weight determinations are more thno conMiutiug than particle counts aud require no less skill in their per ks iiiiiimv. This is tho main reason why the micruscopic method of lu-.t cpiuutifivation bus been widely used. UiuMitlrjiihHi ,,f elnlrinl precipitator samples "I be dust t`t>lh>rti*d on the .strip of celluloid foil used as the collecting iiiiiliiitii in (bo electrical ]re-ipUilor, luuy bn washed into ugraduated I BB 0020009 | mm SMWWAMAWWWAKMWM 2503 44 iluslc and then examined microscopically in a manner similar tn tlmt used fur impirger samples. For gravimetric mdy*U one only mini* to placet the foil wit 1* it* adhering dust into a special typo of weighing bottle and determining tho weight on an analytical balance. ThU weight subtracted from tho weight of tho bottle and empty foil yields tho total weight of collected dust. Titration methods for soluble dusts may be used in lieu of direct weighing. QuenllCnUioa of paper tUimbto sample* The method of quant idea ting paper thimble samples and the pre cautions to ho used in tho analytical work involved, have already been presented in detail, in that portion of tho previous section dealing with this device. GaantlUcwliun of konimeter samples Tlickonimeter samples lend themselves only to the countingprocess. Tho glass plate upon which tho samples are obtained is adjusted on tlio mirroscopo stand with tho aid o# a special holder with a pinion similar to that on the konimeteritself. This ^ device enables one tn bring the various |\ dust spots iato view much easier than Jj could ho attained with tlio naked eve. tj Tlio mieroscopo is provided with an ocular and objective) and so adjusted to give approximately a 200-dhnnotcr magnification. An S-millimeter o!>jeetive and a 1021 ocular have been Tam is.--ssMiMter oceiiir wmmu( found to give this result. A microm eter screen placed in tho ocular is so designed as to have two cross lines winch outline 0 sectors (fig. IS). Before counting a sample a blank determination is run on unused portions of the glass plate, usually on four sectors. This blank number, due to impurities in tho petrolatum, is subtracted front the subsequent counts. Tho petrolatum (vaseline) generally used has a refractive index of 1.4S, enabling most dusts in industry to bo readily risiblo. The dust spots are adjusted under tlte micro*eo|> so tltat the sectors dtvida them symmetrically. All of the particle* in one sector are then counted;Jy rotating tiio eyepiece other portions of tho *jwt aro brought into the sector. Counting four such sectors on one *j*i has been found to give a representative result. Subtracting tho blank and then multiplying by 10 (till luivo Ikh-ii conntod ami 10 lime* the eouiil will give the dust lit the entire circle, 300") will give the duet count in tho entire spot. If tho instrument samples n volume of 10 cc then it b not necessary to multiply by 10, since tho 30 count r m WTHH1IS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES# INC. DID NOT COME* FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. T nri' *'iUir i*. .u* tttly s. 'ij^Bpe. of tif5l babtt*-r. ml empty f*i! % i method* fur .intples and tl*.- j. olrod, have aln- vioUSSOCtioll tho countmgpn * ained is adjusliil . and with tho ait! *. riilt A pinion sinii!. nimetcr itself. TT * to bring the van*.. ewinueb easier tl:.. with the naked >.. 3 provided with ive and so atlj : ;le` 20;>-tIujntfi.. A . dirti!er tf':\^^ar have lit*! rSR. A mirp>u.; in the oeiitur is ?<* 19* sectors (fig. is).' on is run. on umi-J ectore. This lilai.subfractcd from ll generally used lias B dustry to bo rcatlih oseopo so that tb* rtirles in one vM portions f the s|-' : sectors on otto *;*' iibinicthig the hlaiu. ro*l and 10 tiaws tl.* 5) will givo the da-' pics a volume of >" iiueu the SO3 cow:: 45 } *;ivi the number of purrieK-* per cc as shown in tho following (,|,ut>vUuu; of particles jn, sytow, orj^XIO 1U cc per cubic centimeter. |W|T.fr r i unification of Owens jel ilost cnnnter sample* The Owens record, which consists of linear deposit of dust, may be ;ttini under the microscope with the aid of a 1& jnm objective and ,1c ground Hlmmuntien. (fig. 10). Park ground illumination may . obtained by- inserting a suitable stop under the substage -..ieuacr. Counts of t he particles are generally made using a Kr-iueh, .iuimcrsiou objective. In order to facilitate counting, the eyepiece provided with a nct-rulwu micrometer of 1 mm squares (fig. 20). Aith the aid of this vrpieeo nucromeI, * a count of Uic . -md>er of particles ::> strip one square !itIneinstiir>eordeecoarcdrosast '*> or two places, mil an average t\ \ y?Coho me \ .\ \ 'fAftfPLf JC/T \ orrcorfA Glass i .ilu*n. ^ This figure t.ultip.icd into a Tiff fiU3urrr//Y& 0/SC yce*x m--virfOwi*ttisnimii***M. id-mwtumr,adgenpiefincdaitniognounsed, will give the number of dust particles on the t:iird. To determine the factor it is first necessary to ascertain the number of strips in the length of tho record; this may bo done uuder !* magnification. For example, with a ji-inch object ive 50 strips in d* length of the record are found; then the K--inch objective, which ** f<Mind to magnify 10 times ns much-as the S-inch, trill have 000 'trips. Suppose that 300 particles are found in a strip across tho **v*nl using a Ks-inch objective and tluit the volume of air sampled ** 50 cc; the number of particles per cc will then be: Sggxig-aooo ll * represents tho munber of strips found in the record, N the number f j*riirJca per strip and C the number of cc drawn through tho jet lakiug the record, then the mindujr of particles per cc of nir*^j-. f tin* same volume of air is used for all the samples and the same *>*'i*ive uml objective are employed, tlicn tho factor ^ will remain NOJErV THIS DOCUMENT WAS NOT A RECORD. OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. 4C Constant. The micro -.cope should be supplied with a mechanical stage to'fucHiUuo moving the record utfrnsii (ho field. Another method of nnmieniting the dust particles in an Owens record 1ms recently been suggested by two liussian scientists, Kagan and liruumstciu (SS). Their method is a graphic one using distri bution triangles, and according to them it is more nccumto and takes less time than the method given by Owens, described here. For de tails uf the graphic method the reader is referred to the original article. QUANTIFICATION OF POISONOUS DUSTS Of the live instruments dr.-scribed in this book, ouly tho impinger, electrical precipitator, and, in a limited sense, the paper tlumblo ore useful in collecting dusts which may be analysed by chemical methods. The thimble has been utilised for the collection of radioactive dusts, which permitted tho contents to bo completely ignited, in place, under such conditions as to avoid any dust loss (4). Tho resulting ash was then analyzed by fusion, in place On on S-incli pyres test tube), with acid potassium sulfate. It is apparent tlmt the thimble may only be *# * * e * '* ** * i * 1 **, *1* ** *, 4 *#" -+ : ___ * * '** * 0 * 4 ' v-N *;- v * * ;% >a 4** * # ** 1 *, s * *4 * * * * * .*-.-.-.*v.O*: ** t *1. V*** ,A.* ********,****. -: >'*** 4 *4 4 ** L- .* -V * ** 1 Mt * S' t*****#** * . * m . 44 4 4 - '1 used under condi tions in wliich it is possible to ash the thimble without loss of tho material under analysis. The impinger and electrical precipita tor have no such restrictions placed ou them. In tho case of !>oth instru Fmvu a--TjrteU Ow ilw rxcxU suul rnfeU onuloi k. ments it is ouly necessary to collect a sufficiently large enough sample to enable ono to determine the dust accurately with the specific mclltod of analysis employed. A sensitive and reliable method of analysis is the other requirement when dealing with dusts to bo determined chemically. Blanks on the reagents are run in the usual mauncr. Both tltc impinger and electrical precipitator have been used for tho collection of such dusts as lead compounds, zinc compounds, cadmium compounds, etc. Specific methods of analysis are used, depending on the material and the quantity present in tho sample, l'erliaps n single example a ill suffice to illustrate tho technic involved in tho analysis of certain poisonous dusts, namely, ihc dclcnnin.nlhui of mini!I r amounts of lead aillrrh-d hy tho impinger apparatus, using leuit-frvo distilled water as (ho collecting medium (5) (:50). The sum- Mrir", > '* v/ i L . HOT C. IIS DOCUMENT WAS NOT A RECORD OF <5 INDUSTRIES. INC. DID NOT COME FROM S FILES AND CANNOT BE AUTHENTICATED r RPQ INDUSTRIES. INC. l~BB 0020012 1 . 2506 : a mcclmnicol stage : idea in an Ou-nns ~H SCtcnitaU, Kagan Je one tiring distri. accurate and lake* Ibed here. I'or de the original article. -SIS , only the impingcr, -o paper thimble are y chemical methods, of radioactive dusLs, aited, in place, under 'he resulting ash was yres test tube), with thimble may only l>c used under condi tions in wliich it is pr 'b!e to aril the tl la without la A the nuiterud Jfeler analysis. impingcr and electrical precipitat r Imre no such restrictions placed n them. Jn the ease of both iiwtru-' ments it is only necessary to collect ne to determine the naly&is employed. A ` no other requirement jcmically. Blanks on it hove l>een used for mis, zinc compounds, of amdrsis are used, present iu the sample. :e the {(vliiitc involved cly, thu determination linger af-parat us, usg m (">) (::y). The sam 47 ples thus obtained are analyzed in n central chomir.-d lrthoratory using load-free reagent*. The method which is ext remedy important, follows: Fifty cubic ccntimelen; of 1:1 nitric acid solution arc addl'd to the wini[do and ilje mixture is evaporated to drym'ss on a hot plate. Care should be taken to avoid spattering. The reriduo is digested with 5 cubic centimeters of 1:1 hvdroehloric arid solution. The mixture is evaporated to a volume of about 2 cubic centimeters and diluted to Iflu cubic centimeters with distilled water. Jn cases where the original residue is small the dilution at this point is halved. The solution is neutralized with 25 percent sodium hydroxide till just alkaline to methyl orange (use }4 percent aqueous methyl orange., 4 drops) then (1:2) hydrochloric acid till the faintest pink appears. Cool. Precipitate by passing Th-S gas through the solution for 1 hour. Stand over night. Filter on a 12.5 cm Whatman No. 40 filler paper. Wadi with frcsldy prepared U-S water to which has been added 0.1 perrent of its volume of IICL Wash the precipitate off the paper, using hot (1:1) HNO, into tho beaker in wliicli the sulphide precipitation was made. Wash well with ltot water. Wash down tho sides of the lieakcr and tire inside and outside of tho pissing lube, using hot (1:1) UNO* followed by hot water. Remove the pissing tube. Evaporate the solution to a small volume on a hot plate and transfer iua 100 cc beaker. Add 1 cc ofllg>0, (sjyrilic gravity 1.84) and evap orate to fumes of! ljSO. Cool. Take up in HO ee of a mixture of 10 cc U5 percent ethyl alcohol (C. P.) and 20 cc of water. Stand overnight. Filter on a 7 cm Itard filter paper (Munlitell No. 1-F). Wasli the lieakcr and Utc paper thoroughly, using a solution containing 1 cc IIjSO, (specific gravity 1.S4), 10 cc ethyl alcohol (C. P.) and 20 cc water. Dissolve tho precipitate off tho paper into a. COO cc beaker, using 10 cc hot 10 percent ammonium acetate, followed by hoi water. It ia well to wash tho beaker first and decant tho solution through the * tiller. Dilute tho filtrato to 300 ec, using cold water, add 2 drops UNOj (specific gravity 1.42). Neutralize after adding 4 drops of a solution of methyl ml in 50 percent alcohol, by adding 25 percent XttOIl to alkalinity, tlien (1:2) J1C1 to a faint pink color, then 1 fc uf (1:2) 3101 is added in excess. Cool. Precipitate by passing H-S rs through the solution for 1 hour. Stand over uiglit. Kilter as before with extreme thoroughness. Dissolve the sul. pbidcs from the paper with hot (1:1)I1N03, catching the solution and *-hings in the beaker in which the sulphide precipitation was made. ttu> pajwr thoroughly with 1ml water, and wash the sides of he Iwnkfr and |ti inside and outside of tho gassing tube with hot '1:1) HXOj followed by hot water. Remove tho gassing lulie. the stdutinu to a small volume, 1 to 2 ec, ami transfer it a I.-.0 t Ix-.-iker. Dilute <* SO ve with cold water. Neutralize, `I'l-r adding 4 ilnijisof an iiipiittusr-oltiUou of phenolphtlmh-m (J ler- i BB 0020013 1 THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM ITS FILES AND CANNOJ BE AUTHENTICATED BY PPG INDUSTRIES, INC. I 48 cent in 1 percent XnOfJ), using 25 percent XaOU free from iron and aluminum. The solution is made alkaline. An excess of 5 drops of 25 pun-nut XaOl I is added. Acidify with 5 percent arctic acid till pink color just disappears, and mid 2 ecof 5 jierccnt avctic acid in excess. I>ring to a boil cud precipitate ns chromate by adding 1 ec of a 1 percent IC.-CrO* solution, l'luco on a steam bath 1 liour and stand in a warm place at lesist GO C. over night. Illter on a Munktoll Xo. 1-1' filter paper. Wash beaker carefully with hot water and tho paper very thoroughly with hot water to remove all possible traces of sr.hih'c chromate. Dissolve tlio precipitate from the paper, into a 250 re volumetric flask containing 100 cc water, using 15 cc cold (1:2) I!Cl, followed by cold water. Wash tho beaker and rod and decant through the paper. In a 250 cc volumetric llask prepare a standard containing sufficient K;Cr;Or solution to be cquivulcnt to 0.30 milligrams of lead, pre> dpitated as PbCrO*. Add 100 cc water and 15 cc cold (1:2) HCL To each of tixe samples and tlio standard add 2 ec of a 1 percent solution of s. diphenyl carbazidc in glacial acetic add. Dilute to 250 cc and mix thorougldy. Estimate tlio lead is the samples by comparing the intensity of tho pink colors, using a colorimeter. The following tables present some typical results of lead determina tions using the impinger apparatus for the collection of tho samples and tho method jysfc deserilwd for the quantification of these samples. It may bo observed tbattheinstrmneutaudiueihodof analysis is capable of yielding results, ranging from the ininuto amounts of lead found in streets to the greater quantities encountered in a lead storage battery plant. Tasme 10.--Lead emteni / air in a ttonyr battery plant ) %( I |l ' * .' -C4 I. I,*:' * ' |W | %*# ' V; %*+% t , iVt !t*. . . -%.**ut*m**t*t.-f**a*1s1-,, M t ! * u .- J HtM iMtf H** . I<'4. . (t*tdK 1- |i Vtinii r<*m h %\4 t* hi 4 m*4 y v * ir **t- Iwr Mtu ittiH ,* a4twir I * ty` . I **%t CwtH TM 4 Taku: It--(W to* am iihI.Ih :f--? ^1'iuw MkWur. 1IV MMMMt XJb* * l iah in is Twut 13.--/Vnrri rrfmir i I --i h nlSTiwt .* .* m-r--* ~ "' ' *llabj*i .......... lW * "` v-*a * H aHb>Mnla la.i. DOCUMENT WAS NOT A RECORD OF MDUSTRIES, INC. DID NOT COME FROM 1t.es AND CANN01 BE AUTHENTICATED **.itt%roiCC jMp ** - 2508 * free from iron ami An excess of 5 drops of ercen t acet ic ncid till pink centacetic acid in excess, unto by adding 1 cc of a jji bntli 1 hour and stand t. Filter on a Munktell y with hot water a::d tbo -emovo all por-able traces :ato from the paper, into c water, using 25 cc eo!d . tbo beaker and rod mul adard containing sidTicient ' milligrams of lead, premi! 13 cc cold (2:2) IICl. add 2 cc of a 1 percent il acetic acid. Dilute to o lead in the samples by using a colorimeter. L results of lead determinaillection of the samples mul ition f tlieso samples. It eti * auu'ysU is capable 2 an. .its of Ii-acI found in d lead storage battery oraye battery plan/ 40 puts 11.--Summary of trsl* far lend 'lust in the air of uordtad-uting industrial estaUiskmcuU * llktliMrfat *stol4i4uucttt Wsrkabap VniteruiKot lewito innildc Mono! air rriwnt Utott..... . art oml avar.lt l.-.<::ury..M.. aiuiw Mroi> ........ t J|3 f) aaa* .jt i-nalm-t* raanuiwiurtiw | rjf ,at * . va** av *aa aa#a * a i*aa#far '...ton fccrl f iri'.ry....--...--. l..p*irf itanti!ulur:or......... ,irj-iU.ji.lJ! fci'.try.............. V.-4 >.as cian iltnd;rj......... k,iwlaRv ipuauuldf'iTtuLrnusn.a..r........ . aw*a .......................... !.nnaa pHal......... krUll gracm'-- Kirrtrk aptiteuaw nnaufaciunnt. Vjlriwlilm fnrtr<T-- 1 <n> njwUirUB-.nc |4 mU.-..-- iUJitag factory..... ............-- raul poekfct factorV-... TattI *ueoto*... Avcn^~-~-- Saarfae room. -I-.--u--tlaUrra..o. u________ AjuukieiMrtowtu cfcmv idIHi.c...._._._. CjinrMI nnei.. >`iif-:r-.h.Ui:i3 nna. M us-imii Hus iuisi Jteri turaHii: Taiaauy wntin;..... l^uhoruom.... trorrw.-itmo:srorooumu.u Cui> tog mia.. rr*uu...----- ------- il:iin;sjJ holtteg ream-.. Miiins ruua,,...,, br.wi uw*.aJ working........ MUtng citurolot* products. J*sulrixinr nan,....,... Granins auinoyct--.... TCur rtuis*r,rytr*sn..a.n...a..i.i.c...t.n..r..i.a..c.. OlivffMUoexM.. ass . ...asasi . IT ..1U1 .10 ..1M0 ......00ooo0gsrr ..0012 ..0000 .00 ..0000 . Tsou: 12Comparing trad Jut in Ike air of cnlomobile repair shops, streets and norJiad-ming industries in 14 cities TnM) nntptss Atones eiuoM to umr^s (tutor WIM) MltlCnma ot Itsrl to 14tutoe aauraaiair > Atoms Mulatto* ss SI SIS * LI! ss SO .10 Ji at SI 0O . * Tha tnuiinmu ratoa* wito ten far rt ol Ifas 3 totopllng V1*"'**;,,...........-r ... 4 rniiir takao to tin miair( oiiipki M nalUgrwi of leui to 10 tow tocMt* at air. tomtoi Xstalisr Ln4 to mlUismM tur tosnhto terms at sit Sum sstattoa Antanrahilan^ paoauitir|tMoai Xrailnal. name to* klteurWa OttlptlU SUarl s*U|itaa AulMMlalrra* twtlto ramtitoi Xanbad* uttog to* itouto totNitoa .... . .. ------ r*"%-oeW+JtNo* ... __ ____ '***t4oaw..r........__..,,.. -- Ul 131 0 0 < S0 A 4 A HU M S14S3 00 s1 . fftt 3 4& a *1 w W UM 3* SS 1! fTt 0f1t sa 1 In Mlitiwitlo lOctiUc attoi THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FlkES AND CANNOT BE.AUTHENTICATED BY PPG INDUSTRIES, INC. * V-TA ' 1S' , -J 1; rn 0020015 \ 2509 * IV. TJ1E numiMINATION* OK THE CHARACTER ANT) COMPOSITION OK INDUSTRIAL DUSTS With reference to fibrosis-producing dusts it Jins been demonstrated during tins past few years that the probities of a dust which deter mine its capacity to produce pulmonary pathology are the nature of the dust, that is, iu mincmlogieal composition, its particle size, and. finally the quantile of dust dispersed in the atmosphere. The instruments and methods used in determining tlte quantity of dust in the air have already been treated. The present section discusses the other two characteristics of dust which ore of importance in industrial hygiene studies. SIZE Or XXBCSTfilAl. OUSTS So far as the size of the dust particles is concerned, it is apparent that in order for any given dust to produce injury to the lungs it must gain access to the parenchyma of the lungs, the site where the harmful effects of ihe dust take place. It 1ms already been shown that not all of the particles of inhaled dust gain access or are re tained by the human luugs. For these reasons it is of some value to determine the size of the dust present in the industrial atmos pheres. It has also been demonstrated in tho previous section that par ticles of a size greater than 10 microns in longest dimension Sre very seldom found in tho lungs. Tins absence of larger particles lias been sliown to be partly due to the fact lliat the number of such particles greater than 10 microns in size present in industrial air is compara tively small when particles in tho lower size range aro considered. Due to gravity which causes rapid settling of suspensions and due to the protective action of the mucous surfaces of the upper respira tory tract, these larger particles do not penrtrato to tho terminal portions of tho lungs. Hence, it is obvious that attention should only be given to those particles which are less than 10 microns in longest dimension. Instruments and methods used is determining particle size of dusts Tito obvious procedure for tho sampling of atmospheric dusts for particle-size studies would bo to employ the sumo instrument uti lized in sampling dust for quantification. In tho past, however, tin* Owens jet dust counter has 1h*cu employed extensively for such investigations, although of Into impmger samples ljuvo been utilized j` ` f..r Mi Hill I. til I i * t r-* : u !>< i ini-r, : iiu! i.;r .. |,t.>!''ti ll t .t -I *.f l.tH' ill i.r** if..- Tomtit i til.il.- |' nnij. to I |. .. 1 Ith'i IU;. f It ttt::l- I'.tti in . I'i. -t ! : ! UttJ`1'1 . 1*1} . ! in it i - - t liitv it >!i - it. - I \|U-- - lw .1. 11 i -s ICUMENT COMEFRO** :^NDC*" AUTHNT'CftTED mnlKTRlES. INC. 2510 w - ?Jt AND COMPOSITION' ; lias hem tiHccucat.-i! i of ft dllil V.'ijjr-Ji thology an: the !.ai*:r- action, its 'iii*, i the aUft'i.-jJicn-. Tie 35 the quantity of diui present wi'liwi Hisr-mw* ii ore of iiiijiortau-c in STS oncemcd, it is apparent ts ii>;**n' to the lungs it luj. -lie fcite where tin* lie; cily been shown -------- . vr ere n ____Pit is of some v.lu in the industrial aUnm revioos section that parngest dimension are very : latter particles hasbeon number of such particle* .odustrial air is compare* Lae range are considered, j of suspensions and due ares of tho upper respitaicncttntc! to the tcnniiud n that attention should' 3 less titan 10 microns in partk'l* **e of dusts r of at?n.-phfric dusts for the same instrument uti ls* the past, hwever, tin* vcd ext*,fi*4v!y for siH'h samjtliK have l**vn utifi/.i*d r 51 for this purpose; comparative result? between the two instruments will l>c shown in a later yiortion of this discussion. `Dio Owens jet . dust counter, describ'd in section II, obtains a sample of dust from the air in more nr less unaltered condition, stneo with ibis dcvico tlic iitniosjdieric dust is directly projected on a naked cover slip. More over, the instrument is small, compact, requires only hand power, and samples are obtained quieklj- and easily without needing inucli skill of operation. Ouee these samples have Iwen obtained and mounted in a, manner already dcscrilied, the. dust particles may be measured by the ue of a filar ocular micrometer at ft magnification of l,Ot.O dianiMier-- (nil immersion objective) (-10). The horizontal diameter of at least 200 dust particles in several representative fields are measured for each sample. "With this magnification it was found possible to measure particles as small as 0.5 micron in size, while particles smaller than this size are easily distinguished at tins magnification and their presence recorded. * I'hntograpliic methods have lx*cn suggested and used for measuring dust particles, but in order to obtain good photomicrographs it is essential that the dust particles be in one plane, free from Brownian movement, and well dispersed. Since industrial dusts are seldom of a uniform size, it is difficult to fulfill tho first requirement. Com parisons have been made between the results obtained with the direct filar mcnsurcmcnls-and the photographic, method on typical industrial dust samples. Tins comparison demonstrated that the simpler and less expensive filar method yielded practically the same results. Since the filar method fulfills the requirements of tliis prob lem it is suggested for use in such studies. Once a sample has been measured in tho manner outlined, the results of such readings may l>c analyzed in the form shown in tlie following table. Tins table presents the size-frequency distribution of various industrial dusts and compares these findings with outdoor dust. Mr '1 J TH1& DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM rrs PILES AND CANNOT BE AUTHENTICATED BY .PPG INDUSTRIES, INC. 1^^002001 i 2511 THIS DOCUMENT WAS NOT A 'RECORD OF PRO INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. TaM.1 14.--5(t#-/rfunry dblrftnffon / Mrfuit* (tuliulrfel |.V>Tnun lit<;wiK la ioto-*I| o comparnf (o outdoor dint KMnld-ift Nmb I Modbut Hn 1H.M i-i.n 1.1-XI* Mi* rrouii In mlnmi* 3*1.4* 1X-XW 3-s.ti J.J-3.W no xn.w &-XI9 1.S-1.I* fK|l'l-*W Hurt............................. (ranlXVIlttr.............. IlnHutuiiln*................. Tr-u^xX ttilHlaoi 1`rwhcf liouit........... . _.......*Tvtfn ........... rout Jr? |:>n Inn t*ai|u. C I'-utKlfif air......... Tafc mlHiiV............ Bl.t<r nidUiLT....................... M : rl !-i 1 'llIIlK.............. l<W.......... - Al'Kiilmihi lint......................... A tillu )1r-|l>31 inltllurl |l|..ltf k............ . Mb*ai'............................. > fIW>ili*il.rli:)*imi_._._._._._._._._....... llu.V ittUGnf................ . tfO Li u in - . .. ____X__*__ i. l.* T. i.* il.i 4.1 41.* IX? ` IX* IX* 31. 1 Kt Ml k* k* IX* w.o RO . 1X0 . i i I ' II. 0 W.0 15.0 1X3 .* ax? ax* ax* ax* ii.* 41* ax* XI. * 1X0 10.0 l 3X1 rx* IX* 1X3 34.1 ai xa so. a S1.I ax* IXII *. 1X3 IX* Sit* IX* Sl.0 13.* IX* 1X 0.0 - J.O 1.3 1.1 1X3 MX 4 MX* lit* X* *.: X* IX* IX* IX* ll.t II. 1 SI.0 X* X* 1.1 I.S X. 1! 4.0 XI .1 t .3 I.U X* X* 4.3 XI .1 . X* 1.0 . X* 1.1 X* .1 X* .......... ___ _ . xo xo ! X* X* 11.0 xo 4.0 X* i.i X* II.* xo 1.0 X* X* X* xo *.* XI i. 4.1 X* X3 3.3 xa X* XI XI 1X3 IX* X* LI X* X* 1.* I.* _____ _ _ .. . ... .... .. .1 '*1 * .. . .. * i.i .............. ............ ........ .......... 2512 i is! 5 5 - tK r'~ 'r ________ : * i * 53 An examination of the data in table 14 discloses a striking di/fereneo between tb'> sizo-frct|Uuey of outdoor-dust and indoor industrial dust. Ninety-seven percent of tho outdoor dust particles worn found to bo of a size less than one micron in diameter, with a median * of 0.5. Practically no dust particles larger than 1.5 microns wero found to exist iu outdoor air. These results on tho size-frequency of outdoor I dust arc similar to those obtained by Owens in London. In contrast with this result it is found that only 3 percent of the industrial dust particles arc le<s than 0.5 mieron und but 32 percent less than 1 micron. Tho average (median) size of these particles was found to bo 1.4 microns. It is evident from the results shown in table 14 that . tbo majority (GO percent) of the dust particles present in tho indus trial atmospheres investigated was found to be between 1 and 3 microns in average diameter with but 7 percent of the particles ex- . reeding 3 microns. figure 21 shows a typical graphic illustration of the mo distribu tion of industrial dusts, plotted from smuo of tho results in table 14. . figures 22 and 23 arc photomicrographs of tbeso dusts, indicating visually (he size of the dusts encountered in industry. * It may bo said that since tho impinger apparatus is used to collect KRinplcs for dust counting that the sample* obtained with this instru ment ohnuld also be used for particle-size measurements. This would l*ca just criticism if the two instruments did not collect the significant Tb-uwii m b tiMcmirr tipoi in an an*jrand nnj- Usuinlr drtlami M*|>olnl ou Um tfdaaltcaWtf * t***IMwry tlhtiiliuUau with w itvrtrt at U Umu ua %iiitet tW*. " 1)1!' 1-1| THIS DOCUMENT WAS NOT A RECORD OF * PPG INDUSTRIES, INC. DID NOT COME FROM i>- IT'S FILES AND CANNOT BE AUTHENTICATED y% BY PPG INDUSTRIES. INC. JJiB 0020019 1 f f 2513 54 sixes of dust pm-twle* with the. same degree of cfitcieney. TlioOweiut' samples loinI themselves more readily fur particle-size measurements than do impinger samples, sinco the sample in the form obtained is immediately available for microscopic elimination, nmy bo readily photographed and moreover collect;* tbc dust directly on a cover slip in practiealty the form it exists in tho atmosphere. In order to deter* mine the sum of particles obtained by the two instruments compara tive studies were made on several samples collected with tho Owens and Impingcr. Tho Impingcr samples were prepared by placing several drops of the dust suspension in tho water on a microscopo slide, evaporating thn water rapidly on nu electric hot plate, and covering the smear of dust with a cover slip. Tho particles were measured under oil immersion with the filar micrometer method. Table 15 presents the comparative measurements aud indicates that a veiy close relationship exists between the size of dust particles col lected by the two instruments. For nil practical purposes, therefore, the Owens apparatus nmy be used in collecting dust samples far pralido-sizc studies. Tabu 15.--CtMpiiHM tdreo* Impingcr and Okwi dtrti mmwremcnt* llNimittanlaM >mmmm..... %.9.n WH...... -- ...... - ...... V-i* - --- ------------ ....... - o-- ImpiiiLU wmt fmml Smatm Jn*co7 |4 Ai.o} s4.t !.. AC4f 1470 u.4 OB tcao Mil S41) 4** 4 m courosmox or ixdustjuax. ousts Tlio metliods used in determining the composition of certain poisonous dusts, such'ns lead compounds, have already hern dis cussed in the previous clmptcr. Concerning tho so-called "fibrosisproducing dusts'*, tho work of the past 20 years on tho problem of dust inhalation has demonstrated that, in general, the degree of health Jwizard associated with the inhalation of any dust, all other factors remaining constant, is dependent upon tho miueralogicnl comjiosition of the dust. For example, it is now established that the inhalation of certain types of dust, such as granite dust (2) will in time produce iibru.4* of tlte lungs, frequently associated with-tuber culosis. In other eases eximsuro to dust may rrsuit in tlm production of a far lesser degree of fibrosis without subsequent tuberculosis; this is true of cement dust (41). And finally, there aro certain tyjics r P10U5TWS, WC. I BB 00 20020^ 2514 ^^pfllcicnry. The O'.vin.,' partif!i-ii/.i! mi^nsunMciiii.: ulc ia the form obtain ->1 j, .animation, may be rc-.ihly >ust directly en a cover >Iij sphere. In order to two Instruments comparas collected with She 0*a*w were prepared by pLeing the inter on a microscope an electric hot plate, and r slip. The particles were filar micrometer method, rements and indicates tliat ie size of dust particles colractical purposes, therefore, collecting dust samples for ul OxeM dart MtWUXMCKit Onw I luiriamr 1 twit 1 j rmnt i i-r. imnd| k W r..* aIS* .* TtW mo so4 IAITSt .4 mo . 531i*t1 44 X 4 as XU. PUSX3 - ic composition of certain -S, Imre already been dis ing the so-called "fibrtwij*.'0 years on tho problem of in general, tho degree of :ion of any dust, all other it upon the mineral*.yicul is now established that tho as granite dust (*J) will in Jtly associated with tuberay result in the production : KubstHpient tuberculosis; Jly, thcro are eurtuin types .r UJJ T i THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. M e<3 o. 5 85 55 S* g 05z.< I Mea S &a . 0 1 8 We ' <xcz "x il. X i im Me3O C .J I J i 2515 t,t dusts whiHi produce little limy fibrosis, o typified by marble ittisl (!'_') iu gemwal, it has been found that those dusts which tiro ldh in quartz content arc the ones which most readily produce a dtothtin:; fibrosis of the Jungs. lienee, the necessity for knowledge cini'i'rnin" the chrmicii] and mineralogical composition of a dust is lillVMHM. t \*ireming tho chemical composition of various mineml dusts fnund in industry tho reader is referred to such treatises on this Mihject ns Tho Analysis of Silica to and Carbonate Kochs, by W. F. II ill.-brand (-13), and The Commercin! Granites of New* England, by T. NH on Dale (4*1), Isiili of tho United States Geologiral Survey. It has been found, however, that a chemical analysis of a mineral ilirst will not disclose the various percentages of minerals existing in Mat ihist. For example, a chemical analysis of granite dust will not reveal the percentage of quartz present in tho dust, but will only tell the analyst the total silica, combined and uncomhined. For this reason there is presented herein a discussion of this very vital subject with reference to ono of tho important industrial dusts--namely, quartz-containing dusts. Much of tho material which follows is taken from an article prepared by Dr. Adolph Knopf, professor of pliyricat geology at Yale University and consultant to the United States l'ublie Health Service (45). rues Silica U tho name given to tho chemical compound silicon dioxide (Sit).). It occurs in nature most commonly in the crystalline form im tho mineral quartz. Several other minerals are also composed of rilirii, for example, tridymhc, eristobalitc, opal, and chalcedony, but in comparison with quartz they are relatively rare. A tong-cstablished convention has led to the reporting of chemical analyses of rocks and minerals in terms of certain chemical compounds (usually' oxides) rather than in terms of chemical demeuta. During analysis tho silicon is isolated in the form of silica, nnd consequently Mm Htcuiica! anulysts of an average granite, for example, is reported as containing 70 jierreut of silica. About 30 percent, or roughly one* lliinl of this granite, consists of quartz, whereas the other two-thirds f the granite is made up chiefly of minerals that are complex salts of qifirntt-ltcariug ncitls. Such minerals are known as "silicates.** The imuaindcr of Uie silica reported in the chemical analysis of the ;*.raiute, .:imounting to 40 jwreent, is locked up in the silicate miiiemk, * hi**IIy feldspar and mica. Tloi ilMiiartion between free silica and cambined silica This nrliitrnry rniivcnlioii of reporting ruck and mineral auulyses *" terms *f oxiilcs Ims nmwitated the use of the expressions "free f iJ!fdidnot aft* DUSTBINS, INC. j BB 0020022 \ , 2516