Document MoaNxx5rpEeMYQ2zoyknK9Ej7

FILE NAME: Power Generation (POW) DATE: 1946 DOC#: POW 020 DOCUMENT DESCRIPTION: Published Article from Trade Journal ,r - i . *. - rji Eugena W . O'Bran MtmtjLia* D irector Francie C. Smith, Editor Huntar R, Hughat, Jr. AjaocIaU Bdltoc Richard L Pria toutiwMUrs Udltor W. E. Coogler s Producilo Uuta^cr V. in M iu Rapi***a/sfiVii il 1, uuKcn, i s t o t Htitii ai., Uoulu faoi. New Yurte 17, M. Y.---1`faoue, l 'I n a A -V M tt'lllliiii K, Ilu tto ,, u. ;i| Uuwtlulu ML. UititlawitiMi. N. J , -- l'iiuma tic. o iu n Munirti K IJurLuR,, t Corlatr ino B o ti, Buttila l N. Y -- pUin*. Ad iir rat a n si. ! . u. C. B alili. HBU Aijiilr.it Unii BuUOimr. ClcreUr) 14, Ohio .--Piioca, C h a rr/ 7A n i v o- K mattati, U t Morta MlcUrmu Ava. Chlctito 1, IH-- ?8 o w . Ceserai 4181. l B. CLttiutli, Auditorium B ld *., *JT Wtot Sto 8 t,, Lo* Attuo* ^jwt^CtlU. -- PbMo, Tuckor .n * L. P to i. i a t i Lia! i t j Bittk Eldar*., DtlLtt, In -P to w , Ctoitni Ifi78. Attoitili fiutoariotitia-- 11.00 CsmiU-- ; rerei* I2.M PWitW Uh HI/ ttf W. R. C. SMITH PU&USHING CO. * jtoklUhtn aito 07 : Colto*, JflcoK I t o t i* * * ! , Battitura J la r d M if, ' J * 4M r 8 *(** * ca n ta i, or X. Batoko, P rtiIrU n i; B. P. Ibjijl U totir Vlm-Prnlik-Dt ; ? w 7 U eA U littr, V ice -l*rH iiiFn t: . a W, O'Brlta. Vlce-protlilcnt ; - i C* 8Itit, Yloe-PrwWnit : - 8. Vlca-arMliicoC O. . TrtAattm-i A. T, Bob u&ertrf atti inattii% Q ttlcn &RANT b u il d in g ; ATLANTA, GEORGIA b f S -i#: a.U * J " v - J S # / / ' . : :C O N T E A , / - t e i : : .^e* t i ` .. * - - * 1* fower ftf T*mp*. by E.,J. Wiwta*n and f, / *.-*. * : IV. 44 :*..Seund Cfloditioning, by Franeh A. Waettwwb .. . ,T.........-44 '* le Haiidlng Mathodi, by John E. HyJr . . . . . . , i . . . . . - , ................... SI _ Virgin!# RyenTir* Cord Plont . v ............. ..................... . *64" Tnto Stydy lmprov*i Rotation* in Indkiftry, by W. C* W*PJ*................ 65 Cniihad Cribbing, by J. P. MeEvoy.......... . . 1', ............. Et M^tllic Cqrroti*, by M. F, Wulfmgboff .. . Rodlanf H*atlng. by Jatnv* A. "-h ........ . 1,. .v . W .. . 60 Mitoluippl Bqckoni tq.lndurtry.......... .............................. .......... 63 put Ebdifurt Systanu, by C. ,C. Hofmann../.. .........................64 cf ItalyU'Wa*. * . py 'RipoaiJ A. B*1I ....... . . . .y ............................................... 66 HarfT Mi j?X P b .yi.P R S ^ ^ 4; ^ . ...... . ...... ' M. j . . ; ...............-- ti p * r 4*y-IW>*tgf' ,-** *; t* * 'Msilft'TJ*'*; im-ia,- ** ^ . aVIbw * . . / . - i V * i$K9b : -y V : v - - fCiili-im*! Sfill.m..irrlii 11** m**j ii , k.i1n0^* *. INDUSTRIAL HYGIENE -- Control of Working Environment Is Impoi T k li third imwtmUment far m dUeuatien ( the corking environment -- (to problem !, their evotvmiion, end recommended eon trot E VE RY important factor in fluencing our Uvea and one which Is given little consideration is the environment in which we work. The general environment dictates our requirements as to the clothes we wear, the food we eat, and to a certain extent our mode of living. The average individual will spend at least eight hours a day at some occupation. The re maining portion of the day is usually spent at home. It is obvious that two distinct problems of en vironment exist: the home or com munity, and the working environ ment There are certain safeguards thrown about the community as providing safe drinking water, proper sewage disposal, collection and disposal of other wastes In cluding garbage, and Immunization programs. The importance of these protective procedures In a com munity has been long recognizedTheir accomplishment Is measured in terms of reduced death rates from various communicable di seases. Some diseases which in the post have taken great loll of life B y N# V H e n d r ic k s Chief Engin* Industrial Ht ?1 Servie*. G e o r g i D e p a r t m e n t of Public Health otherwise harmful tubslanc* 1 final objective In any Indu hygiene program is the gllwi**j of health hazards incident k>dustrial operations b y the u * < scientific methods. have by these methods been re duced to a point of minor signi ficance. As civilization has pro gressed with an accompanying complexity in our living, the neces sity for public safeguards in the community has been given more and more consideration l i is only through these approaches that the proper public health measures for_ the community environment can be applied. "For a number of y e a n , consid eration has been given to the de velopment of certain methods b y which the working environment of an individual may be modified or adjusted to more healthful working conditions. M any plant op erations b y the very nature of the materials processed and b y the mechanics of the operation pro duce an atmosphere of toxic or Occupational Stswuw Industrial operations require 1 use of many materials, oca*, which aretqxic and produce 1 ful effects on individuals who ' exposed to them. In addition, I are certain physical condlH which exercise harmful effects I the worker. The deleterious I produced by these materials conditions may, in a broad i be termed occupational diseate*' In some states, industry has I legally responsible for th e ,< on the worker which is about from such exposure*, legal responsibility ha* been dssjg noted, code* or schedules have bej established for a rate of compenwfl tion covering occupational dlsesswg Such codes vary from all indiwiig loss to those w hich cover o specific occupational diseases. ,;^ri jEjj c r a n i AMO AFTCN m t t A L U t l A i i 0 * VAN* AfllO APTIO N IV A T E * IH M f R6 CBi1 Im Q B (P A * T N K N T OF I L K A O K U Y ANO D Y t W O iO . V. 4 4 '2 T ' ' V tf*. V . , -, 8 SOUTHERN POWER l INDUSTRY for JANUARY, I In considering the potential de* velopment of occupational diseases and the responsibility and cost In cident, management cannot escape the fact that the condition of the working environment is an eco nomic factor expressed in terms of the overall cost of production. Proper consideration to the status of the environment, in many cases, w ill directly lower the cost Recog nizing these facts, management should take every possible means o f improving and controlling the working environment. For many occupational diseases there is no known medication and the logical method of control is the adjust ment of the working environ ment in order that the exposuir from which occupational diseases result m ay be removed. Processing And Th* Environment T h e working environment in any plant will be dependent on these factors: (1) materials, (2) process in g methods, and (3) process equip ment. Many of the raw and pro cessing materials used in industry are specifically toxic and toxic compounds are often liberated as by-products of certain operations. In any case, the type material and its presence in the working atmo sphere will determine the existence of a hazard. Fortunately most processing ' materials are non-toxic. However, with many industries it is impossible to avoid the use of certain specific compounds which rutti kfvovac. *<! ton caaA titT ias r u n t * r|,OM r i c a n a s tamii. are known to produce harmful effects on individuals exposed to them. The method of processing is im portant as it w ill determine the ex tent to which materials are dis persed into the working atmo sphere. Important factors associ ated with {process methods in clude: U ! temperatures required for various operations, (2) agita tion and other mechanical details, and 13) specific operations where by-products are formed and hb**'' ated. , Equipment plays an import** role in determining dUpenk* since the design of such units call for open or closed opentkw' rotation at high speed or close * frequent observation on the port .1?. of the operator. Specific de*^ would determine the extent ta* which certain control installatW. such as local exhaust ventiiitfe* might be applied. o p r a t o li iu n r tk o i a b of caiiaom a l a c * irto a n p u r y bh* c - t r o u t an d a f t e r in sta llatio n or ou*T ano rumc *****> IYITCM* SOUTHERN POWER * INDUSTRY ter JANUARY, 11%,. 1 avirttuntti PcabloM O f importance to Industry is the matter of controlling dust, For tunately. there are relatively few type at duat which are specifically toxic- The more important from an Industrial standpoint are silica, as bestos and fin ely divided salts of toxic metals, such aa lead. Silica and Dual Exposures to free silica are more important from the standpoint of population exposed and deserve more consideration than those to asbestos dust. However, asbestos dust is just as toxic as free silica. Wherever sand or materials con taining free silica are processed, exposure to the dust is likely to result This Is especially true In foundry operations, abrasive clean ing, blasting, and the like. Suffi cient exposure to concentrations of free silica often results in the pro duction of fibrofcie growths in the lungs of the exposed individual. This condition is known as silicosis and is one of the prime disabling occupational diseases and has coat industry considerable sums of money for compensation. Asbestos dust although specif ically toxic, does not result in a numerically great number of ex posures due to its infrequent in dustrial applications. However, in the production of asbestos cloth and other products, a serious prob lem of dust control is presented. Certain heavy metals and their salts produce specific toxic reac tions. M any industries employ lead and cadmium, and their application to plant operation usually results in the creation of an actual or po tential exposure. Lead compounds are particularly important in such operations as the manufacture of storage batteries, printing indus tries, and the production of paints or pigments. Ch m Gases are usually classified ns either asphyxiant or irritant. In dustrially the more important as phyxiants include carbon monox ide. hydrogen sulfide and hydrogen cyanide. O f these, carbon monoxide occurs more frequently. This gas is associated with the combustion of carbonacious materials and is cx- tremely toxic. On entry into the body it oxerts an affinity for hem oglobin which is about 300 time* the affinity of oxygen resulting in a tremendous decrease in the abili ty of the blood to carry oxygen and produces s condition of as phyxia. The more common irritants found in industry include sulfur dioxide, chlorine, ammonia, and the oxides of nitrogen. Although these gases are extremely toxic, they are suf ficiently irritating so that the in dividual exposed usually has some warning as to their presence. Under these conditions the wgrker can normally remove himself from the exposure before too much damage is done. However, these materials do occur frequently in industry and the importance of ex posures to them should- not be minimized. Vapors Vapors come from organic com pounds both of the aliphatic and aromatic series. T hey nlay a tre mendously important part in mod ern production and th eir number and use is limited only b y the ingenuity of the chemist. They are used widely aa degreasing agents, intermediates, solvents and clean ing compounds. Most of these materials are ex cellent fat solvents, and on entry into the body tend to go to the nervous System. This,is true of the aliphatic series, including distil lates and petroleum. From the standpoint of pure toxicity, prob ably the most important of these materials would include benzol, its homologues and the chlorinated compounds. Sufficient exposure to these compounds results in chronic disturbance and in some cases dis ability. M iltt Acid and alkaline mists are as sociated with plating, stripping and cleaning. Chromic acid mist is probably the most important of this class of material, and results from electroplating, anodizing and similar operations. Exposure to such mists may result in perfora tion of the nasal septum, and if cuts or abrasions are present on the exposed parts, ulcers may de velop. Funs Fume are usually with welding, cutting. rations where metal v s ` to high temperature*. Tn dustrial standpoint, lead, s t e cadmium are probably to*' important. Atmospheric fr~ this type are often found pouring of b, welding or ing of galvanised metal or a> ^ temperature operations InvsWI/ surfaces coated w ith lead ` " t " paint. The physiological respond t o * j r!2t inhalation of these material vary considerably. The less condition is known as metal I- fever which carries symptotf* w*? zinc oxide. It is of short duntt*:"' and no permanent tissue dM* 4 li done. The more erloui ** _; tlom arise from the exposur* to.-, fumes or metala which are sjwddi' cally toxic. Physical Cftrutitlnp* Physical conditions such to-] working positions, temperatuf* hum idity and abnormal pressure' j .p lay an important pari in the *bk- ity of the worker to produce. W* correction of such condition ** prim arily a problem of engine* ing and when given proper coda** eration will do much toward in creasing production and lowering costs, through improvement *1 qu ality of the final production, i f duction of spoilage, and IncretM in the final plant safety. Evaluation of Enriro&mant In order to properly evaluate 5 the exposures in an industrial J plant, a detailed engineering stud; [ and analysis is required. Such * , study in the form o f an industrial I hygiene survey is a mechanics! J means by which the plant is ob served department b y department | for the purpose of noting occup- , tional hazards and unsafe practices I so that they m ay be appraised- f Such a survey should include work analysis, analytical procedure 1 rating of hazards, analyse of the hazards and recommendations for control. 1 T h * work analysis should to made by noting each and every job carried out "in the plant method of process, and hazardous conditions to which each worker 74 SOUTHERN POWER * INDUSTRY for JANUARY. 19 J '.J K if f C Q M M W JW O C S S & S IN G M v iT ^ a tlA L S W IT H SAFAS C O N C S N T A fcA T lO N ANSA A *H Y 1- i O L O lC A L S Y M P T O M S TXXB matg r a f t w su sx k x u . use coH O jasB A iioja n rsio u > o u i w omse ft : 1. / i V* .1 -C 1" :q :i - I Sentala A*u,v(d* S alU u AtmibIc (toapoBads ttnualet batial C*4miy1aa Carbon Dl.dlfid* Jo .. I - i 2 .iU i `h e | is i c r - ft .id . 1 1A* 1 m* q| re* : m i <4* 1* lxi*l j tudgr I cn t J 1 t ^ i I > s k - I "W 1 j i u i * . 1 *i i nL i .4 t 1 ddior ] 4 Ue J jerboa TuTflbWrAft Qhkirl&Aled Dlphasyli QfeLsrJAo QilortfbBBBC du w alu a Cempouait *i>jkD bkbtoxldt tfwiaaldofcyde Hidmeklario UU JIjilOfBO ftoilUU M 7 Allien DiUll nm > ftT -u. . if f faiata* kw Orjfuiut" k}xifiriit; yafje. military g n w ; ***ap ini rarnlsJi; furtUuor. Urfvfiii1 |ifr|nl!ti(MUi! reirigerarfuuJ, Emaa* iR<; dy> Ail color n iff.; *u*r rafiabtf. U rp u ic MYUlhraii; dl/m blltf.' paint *ad ntJnUfc; d la la iw im ii oxplnsive. JaM*saa aiiil |iiuiruU ; IrAitier |u4uLry; iu-_ BKiidiftui; ttUnilif Mini i Uv1i1ni{; ujta aud. V AnlA mfy, urfN lik kynlbril*; dyei; bromidu: rx- tiulvrui; paint and varniih reiuuvnn; dye; varoMli w/jf,; rubber iaduhtry. Alloy* i CsilbliilUi alia; rlivlru-|ilklin^; Mlor* #6 IthUwrieb; lead hud MM *uilitii,`. U ukulil; ml%. v iiriuc r*\u u : **ruiuk+h.; liupaUrM ri; v.rfeuu 1*0 *J.iurld. Hit* Iron und alvei; enamel; IliumliuiiiiK * * * ". kiln sipTa*ipo*: hOMtlUne. riuiw oi; milt, i-l.aplng rvmyouud; dji*: |H|iu4 *4 i*i**r lodutlrkii. JKIeu|.rJc*l equipment; Ucque-r n ix .; iiaiuu. wm; m il. OrtfaPic w/Olhral*; IrAllI bleaching: a*|ur punficaiiwn; cfelarjnaliun. MVfHI fur cdluliMs acalIt*, ri'siiu, uiln, lil i dry cldbalfl(, tljralnr; O lrU lIurjy; rlrrlru|.UlluK. Ill'll,! Ins: vanning. Organic A jo lh r.il, Mh'iBfa: ililnurr fur lacquer. Organic aj'uIbral*; dye; mhhr-c j>uihft; Jealbrr; ynlbplie m ia and lnof:i<r*. Lnaibrr liulunlry; prganie ayaUiati.: tinh lu ifi; *a(f. Cfalbridaa. Kai(Fttl; lA alyiiral cltnulatry; vin'ohr ruVHi! siitiiniuf j jaoiUvr ibnniiiK, suiniu nd lurlljiw ; yapar mig. OliuuictI flidiyUABl lead iltjcnirula; Itu)*; lOrar* bhiu-ry mfff,; ii^*'clcid(*. 2*ru|i. imwnurj m Iu . *rtroilfk iiiair<niirMla. du'mlchl lirocveain^. yunaUni-a; .| g r Iiiaveiry; mliraairr rlran Inti blxllni. Utifrlgorraiiuii; b!rarhiii|;; m iluluhr; uMi.n,'; naluiu^ and lforlilleare: rwfiuJiijr. i%|ilyijvr*; JHlftisI; lealkcr; li*aiilia; lirntlraU. lftwHcul; imiul and \afiti>lt; urjiinii- iir*o ATAllniN: diP add 1`arittaJi; rulxLs-r imlu-lr>. N vldlurxv; gnlvtnUlug. I.n.~, li.u i.j.ir, . Writing. i.u ppm I lib - |i|ini 5.U nvMn u.$ ujr/iP l.U l'l'Hl iUU |I|IIU 0.1 IUA/S4 - Pi'IH 1UU i'jua 1U0 a|aln l.U utf/X? i.u ppm Tf ppm U.l m v /iiu m u jtpm 2 ti puui ill ppm piuA 11.15 lug/51* V.l i u t / 31" C.oiio.vgu p.l'.r.f. Ill lu-vl H |l|llll -WU |.|<||| H uiu/M ftrrilh&ion of akin aliil uinrvu* luifrali**. uf r y n *4 rcspiraiwry ftratfl, Uyepnua, brunciuiih. IrrilaiMk wt rreplnilury paaaaKaa, UBU|[1), jnUusouary v ilm ii rrt i ujfa irrilklioH, huhilfi urlloa OU akiliU uw ulur wrakuraa, Vpriiuu, cyanuaiK faiui* InkV M 'n iu k ymiiiDM, iiim of ct|hiiibnuuii IIIHkURi VvpiiOjC, diarriksa. l futiia in Aiutuacii. itJwiiim;. diurriira. brad* m*I|Pi Kia|ric 4iltirtu|UCk*a, akin UlMTaar, lu*a uf lialr, tvM klim . JrnU U op uf uir pufattfun. brvIP'llilUf guar* li%illa. aklu milllull*, diat'uluraliun uf akin. llrail.uli mill vrrvigu. gaalfu iblrallim l illcurbnncr. tarmurrlingm. Injury In bliwd laris. 4 ug vrgnna will, diungr In binad nielara. In* jury la bland m w l* . bunn. llrar. k ld n . . nc. a*wk tkf NPpelilv, woBkuaais. itiUsrh, infUui* 111*libia of tin- lunjch, cuucll. evruntMU uf cbenl. vacia iliHidliuh1, %'crl<|frg wuiibBve* Mania! diaiurb- Hitfrk, Irrliaflun ui akin. il the. ialiiftlJn*u* uf v jrb sll, ibcubbibY of Urmplva. issakiiBid, Uauaba'. vumiUnf, Jabrftaked rrkpiniluA *uil pulur, cwllipir. !rrl(hiiull uf uohu, IkruaL uild iij. IkaU.* Jic^4^rlii>l ruiiiiliiiii, cuafiukiu, u r c M , ih ju rj iu ljKr. dermalili. .Vuaaftfra *kla niplivUt, jiwudlcu nd Blruplor ui 11war. UuU> eardipu ^*rl>aia; buruina. bibltrlfl|!. trAufb, >bronchiliw, ell'AMlc S iu a b i, hmsI aad lirunr&ii] calarfli'. Jlaud ark*. KllidU^M. UltfAli uhau^ra. Jiro/ichilisj broovliupueutBooia, auunkia. Ilvph' riiia. ulcer* of Akin xuft Ueukbrjuae. ptriur* 1 Itun vf uaHl avpiupi. irriiuiian uf r>*k *ml mir, rerift^u. uaruu* crjuiUilr mf rallk It rX|)inUr b pfOlbP^rd. XfrlluliuH of murJUA Mazuhrauea, ewiiuAtfiifilU, MtivefB d-nuhlilla, drCnorI4fH of livor. Couyfallir. broncbMias dcikiruflUuB of leeih. eoaIfaClioil if lbrvhf. VAUellc AClIun on *Wo. CdlbHrlivllU. rXllhUwil, pallor. 1MI1 in eyt>h. nuar and Ibrsm!; hrudachu, (flDYVldeni, pint* yaia. Wcfekupaa. pNllurs 1 ttf kPPOlOg Ibid lipr. un-nUa, coikkliphtipn, trosup#, colic. lliriaMlUuliflii uf fuilka Uild lUUfuuk BiauibmiH* Itt Uui yuuulb. nwruala uf U>p i i v , tiilUrllii, Urmia, irriuura uf vltp hand* HMii facn, FibrOlic lung liintc, duv.laym .nl a t ilUcsuiu. llrvrrhlli. vpiiKhinx, lararuidiia, bruflebuynau* diwnlJh t; iil^nlvn. Acuiu asid i hr** bruurbille. brvH*liwpo>oiihiikla. d-`i*i3 uf Ivelb. iln din aiciii, paiu. sw|r>ifita aii| iilrvrailiiii. Kurrulic a((i-i-t. huudkull.*. rnrllgu. g.uli'uiiiuuliusl ill.)urU ni'c., Injury U> liver uud iit<r%iiiia aj AK`111. ftiHel fiMcra; iiriiaiiuii uf ruaidralufj irurf, Hcadaclu*. unuava. uiillU, pain Iu Jiuib*. 14 fct i "j t n j j *! t! p I m l `Jlj < h W iu * ' * % I 6 ;- v " NOTE IM'.lS* -- 1'ari* uf sulrivim-f milli.in |,udn uf M*r l#c vj|ui|ir. mH/atrr ZT &lilli)rBinuni / u iln iu nofrraojKba*lrHr.uv*li-ifluTi*rlu*br luef (aoiurt. uf sir i . i t * J j j I f l t t N PO W ER & INDUSTRY fo r JA N U A R Y , 1946 jn 75 r i ii . * 1 i. : 1 1 u exposed. Toxic materials when present are investigated from the standpoint of the liberation into the atmosphere; physical tate, whether or s o t the employee is re* quired to be in the area where this material is dispersed, and the probable effect on the individual. Analytical procedure usually inelude the collection of field samples and their analysis and the comple tion of other measurements when necessary. Atmospheric samples are collected from the breathing zone o f the exposed worker and are taken In such manner as to be representative of average working conditions. Actual sampling and analysis o f the atmosphere is the only scientific means b y which a known exposure may be ac curately evaluated. Some toxic ma terials make their presence known b y odor and other properties, but these do not offer a means of de termining their concentrations. The rating of a hazard or ex posure is a measurement to de termine the degree of a condition and the effectiveness of existing control methods. Much work has been done in establishing safe permissable .concentrations for some of the more common toxic ma terials These threshold values of fer a means of determining the ex tent of individual exposures. B y an analysis of processing methods, rat ing of hazards and study of ef ficiency of existing corrective measures, a baseline for adequate control procedures may be estab lished. In most cases processing methods w ill determine the type control indicated. Application of Dale When the industrial hygiene study has been completed and ob servations and data analyzed, it is necessary to translate this infor mation into terms of specific con trol procedures. Unless these data finally result in corrective meas ures, a great waste of time and ef fort will take place. Although the plant or process engineer m ay not he primarily concerned with, ac tivities other than strictly process ing, this individual should take ad vantage of information obtained through the industrial hygiene sur vey. In many cases, a study of environmental conditions under which a job is carried out w ill o(- fer the production engineer a means of increasing the efficiency of the particular operation. Tha plant engineer should also be concerned with the industrial hygiene information because the control procedure applied w ill be based on an analysis of these find ings. The design and installation of such control procedures as local exhaust ventilation should be worked out with the plant engineer in order that the f in d Installation m a y .b e entirely consistent with processing requirements. Control Procedure Hazards associated w ith Indus trial operations can either be eliminated or reduced to harmless limits by the application of public engineering methods. Procedures for the control of such exposures usually consists of one of the fol lowing; Isolation of the process. Fre quently a job which is productive of dust or tends to disperse other materials into the work area can be removed and loealM a point so that the liberation of such ma terial w ill not contaminate the genr era! working atmosphere. It i*. oc casionally possible to close off in dividual operations so aa to isolate them from other areas and control the exposure. Substitution of non-toxic ma terial occasionally offers a good method of alleviating specific ex posures. Where toxic-materials are used and it is possible to replace them with non-toxic substitutes, the exposure can be removed in the easiest possible way, Wst methods can'sometimes be applied. These are frequently used in the atone industry in drilling, crushing, and grinding. Where ma terials being processed must be kept in the dry state, this method is obviously eliminated. Personal protective equipment offers an excellent control pro cedure where the exposure Is in frequent or of a short duration. Where this type of equipment ia used, care should be exercised In its selection in order that the equip ment used be designed for the particular exposure. O nly equip ment which bears the stamp of approval of the U. S. Bureau of Mines should be purchased. Some exposures may be con trolled by mean Of i I r io n . B y this procedure d e n t amount o f air 1 into the work area to contaminant to a point 1 toxic lim it This method tain disadvantage, uch handling of excessive. air, and the failure to.; centrationa of the material point of liberation. It 1 i or dose to the point of where real exposure occur general ventilation, in mod i does not correct this situation. Level exhaust ventilation the moat effective and * the most efficient mean of trolling individual exposures.-hood or similar typ e of device is located as dose si sible to the point of liberation j the contaminant and sufticket i handled in order to remove material in such a manner that h i not dispersed into the work This typ e control should the material before it has an ( tunity to come into the brea zone of either the worker on individual job or the workersJ the surrounding area. In considering the matta."' local exhaust ventilation, It is 1 ly essential that .these instahat be properly designed and neered. In too m any cases and th e entire exhaust systems < installed b y mechanics or. Individuals in the plant add thought is given to their'dedgn I the principles on which they l operate. Unless such systems based on good engineering there is no assurance that th e : stallstion w ill operate In such ! ner as to control the exposure The next article of this ssrtol cover organic solvents and similar dustrial materials, their ptovtrtm and w e t aw they influence the **. vironment and health of the worker using them. 1945 INDEX A v a ila b le to Subscribers \ I f you keep your back issues* -- write the editors for i ; ( free copy o f this Index. See Pagi I t 76 SOUTHERN POWER 4 INDUSTRY for JANUARY,