Document Ej8zMxvV7Jmm71ndxJxdx16j

m. & toJ v?.TT IMrig witliii \Ofl Kow pvc Processors Can Cepe ft may take some effort. And expxir.e. Dot you shouUt be able to protect your workers, comply with the new OSHA regulation and stay in business. This comprehensive report is interfiled to help guide you through the provisions of the new rule and suggest approaches to meeting its requirements in your in dividual plant situation. By Matthew //. Kaitove, Associate Editor the U.S. and Europe revealed a total of over two dozen cases of this disease among monomer and polymer produc* lion and PVC fabrication workers.) Publication in the Federal Register on April 5 of an OSHA Emergency Temporary Standard limiting employee exposure in VCM and PVC production and processing plants to a 50 parts-pcr-million ceiling. one-tenth the prior limit. The standard also required regular workplace moo* itoring of airborne VCM by no later than April 32. First public reports in June of two angi osarcoma deaths associated with PVC processing and arcther two such deaths of persons living a few miles from P /C proc*. cuing operations in Connecticut. OSHA hearings in June and July which produced vol uminous testimony from representatives of indust y, labor, mcd:cal science and others on possible health hats tit from I'pr VCM and industry's ability to minimize these hazards. . v Announcement last Oct 1 of the permanert OSHA standard on VCM. effective Jan. ], the ma)or Jmt of which is to limit exposure to I ppm averaged over II hrs and $Jr\ !: rr^xir.;u.'M Mkwiiuiii oi a ppm averaged over'15 min. A l this Issue reach** you, the begun toward the Jan. 1 countdow n deadline of will the have most already er-.iical challenge yet to face the plastic* industry. Ilardh .iry- one involved in manufacturing or handling in\| chi.-ndc monomer (abbreviated VC or VCM) or the pvc revn made from it i* now unf.imilt.ir with the dramat:; ch.i n ul events which ha* led to the present cum* atmosphere. 5*'-ic of the major link* in that chain were: TU.- announcement late lust January by B.P. Good* rich Chcmka! Co. o( the discovery of tlucv deaths KMccn 1908 and 1973 of long-time workers m j Louisville. Kv.. PVC polymerization plant owing to a very rare cancer, angiosarcoma of the liscr. (Subsequent intensive search in Where are we now? OSHA's Jan. I deadline leave a seant matter of weeks before the effective date of a standard that some monomer producers and most PVC makers say Is impossible to meet with any known technology short of putting men into respirators--an alternative fraught with its own Urge difficulties. At for the PVC processor, whose only possible exposure is from the relatively small amounts of residual monomer trapped in the min. the burden of the standard on him is assumed by its authors to be relatively light In feet the industry consensus seems to be that most if nos iff. proc essors should he able to keep the majority of worker ex posures within allowable limits by instituting certain en gineering chances--mainly, increased ventilation--or workpractice modifications at reasonable cost. Most experts, agree that the major problem for the processor under IKe new standard may he its ultimate effects on resin avail* ability and tost. (See also p. 25.) SP! and about 10 chemical firms have gone to court ht hopes of having the standard sent back to OSHA for re vision. and have appealed to OSHA for a stay in making ihc ni!c effective. Whatever the chances of seme relief heme -ranged, cither bv the end of this month or later, lighter restrictions on.VCM arc here to stay, and the PVC processor would be svc!l advised to understand the new rule and know in advance what is required of him for compli* ancc. Tills is advisable both to minimize a health risk whose full cstcni is still cnlv cucsscd at and because of the new and c'oscr lo^k OMIA is taking at processing operations//; While the plastics industry has not until recently been contidcrcd a prime target for compliance inspections, an OSHA standards official m Washington says that firms DCCtMKI 1174 RSV 0006636 >7 u. :r. *. f- ft! M f:i > ten ft r /'ihMufacturinf VCM and TVC "can I'fGfc to |(t lo know an OSIIA in*pecf'tofto Iht near future." And the word tfrom the compliance iC-,lt>n ^l,, jfof PVC* fabricator!. While in one Kmc ihe Mandard may be said lo be aimed mainly at monomer and poly* mer production. where workers arc subject lo greater potcniial exposures. likewise be of interest to the PVC processor hiv-iuv: it indicates how an insjvclor w-1| fudge compliance- Huth document-. ill he public!* available from reguuul and area offices. If you want direct answers lo in dividual qiu,lions about the standard or its application to a given work situ ation. a recommended starting point is According t> drover Wrcnn. sWcf ^ lliv l)iv, of I k.dlti Standards Develop- `.R ntent. the siandarj K spcvillcally not intended to regulate certain proeetsca..! that involve only partial healing of 1'^v fabricated material, such as riiermo* forming, heat-scaling. cmt\osslng, shrink-film or hli>tcr ppckagiejt. Opinion in Washington seems to be OSHA alto ha* its eye on processors, the Div. or O-'-upational Health Pro that scrap is exempt "fabricated prod who employ ihe great bulk of those potentially exposed--an estimated 350.000 vs. some 6500 workers in VCM and PVC chemical operations. So be prepared. gramming. Washington, D.C. And for down-to-earth advice on what to do in your own plant, your PVC resin supplier is probably your best bet. Not only has he been living uct"--at least until it's subjected to ! further melt processing. Coverage of the standard in this area still looks questionable, though not if virgin is re-1' extruded or moUkd together with the : Recognising the urgent need of with the problem longer and thus has xernp. But even if scrap is reprocessed many of those alTectcd for guidance experience <n monomer detection and alone, it would he pruJcnt to monitor ' and advice, this article will try to pro* air analysis, but he's likely to have for VCM. though technical experience vide answers to frequent questions on his own processing facility as well and to date indicates that little or no vinyl how the standard applies id the PVC so he intimately acquainted with your chloride monomer release is likely processor, how he determines whether problem. Rc'm suppliers have been from this source. he has a VCM problem in his plant and w hat lo do about il if he hat. The in* keeping their customers informed through letters, bulletins and other Another b.vjc principle of the stand ard is that it aims at regulating in*.' -71 formation presented her-' has been means and. in many cases, have done dividual worker exposures, noi abso-^-y, gleaned from interviews with Govern actual monitoring in customer facili lute concentrations in air. That is, it h - ment officials, health researchers, ma ties. primarily concerned with amounts of v;i ' jor PVC suppliers and their custom VCM actually in the worker's breath-.. ers. makers of analytical equipment Fin:, know the '.aw The initial state ing zone (defined, "without regard to and independent testing laboratories. ment regardin', ecpc of the new VCM the use of respirators") and not those ":Vi In viewing what's still a fast-chanting standard (29 CFR Part 1910. Section in nonwork areas, such as inside * , V. situztioft, this article tries to pinpoint, 19I0.9Jq> reads in part; "This section storage silo or just adjacent to an In- ' '< whe-e possible, what's presently known applies to the manufacture, reaction, jeetion machine nozzle. Furthermore, and. to other cases, tries at least to packaging, repackaging storage, han the regulation applies on an individual- warn where the question marks re* min. i dling or use of vmvl chloride or poly- ...V.i c* !viiw< rfliw wtr polymers), but does not apply to the by-individual basis. One worker maylUu. ...... ... *t.*...! *14 ___V..-M.1I.M-H.g uMAM!M1W, .IjJJf'X1' *' another at a different job or location The ivople to Ihe knew Before turn* handling or use of fabricated products in the same plant may not. ing t> specifics, here are some general made of polyvinyl chloride." What's more, the standard provide* remt rks about two important sources "Fabricated product" is said to mean an extra incentive to achieve low VCM of -^formation regarding VCM-- product "which does not require fur levels by promulgating the key concept OSHA itself and your resin supplier. ther processing at temperatures, and of an "action level," Kt at a 0.5-ppm First and most tmponant. no PVC proe tssor should be without a copy of for times, sufficient to cause mass melting of the polyvinyl chloride re lime-weighted averace. (TWA t* a measure of what levels an employee the t null standard. Reprints from the sulting in the release of vinyl chlo was exposed to for how long in varl- l f Federal Register should be available ride." oils work stations.) "The purpose of ' free from your regional or area OSHA While OSHA apparently neither has the action level." according to the pre- -`^ office: or else you can write to the Su closely defined "mass melting" nor in amble, "is to minimize Ihe impact of perintendent of Documents. U.S. Gov tends to do so. it feels that the limits the standard on the employers who ' ernment Printing Office. Washington, of what is eovered are pretty clear. have attained exposure levels well be-^-.y D.C. (request Part II of the low (he permissible limit. Federal Register of Oct. 4, 19741. Reprints of the OSHA standard cost S.75 per copy. Table 1~KMRlOYEIt REQUIREMENTS* Exposure level, ppm Thus , . . employer* may. in^, ^. effect, be exemoted from some provisions of the stand* Two additional documents should be issued by OSHA <0.5 >0.50.0 >10 aixt." Or. as one industry observer puts it. "The complex- before Jan. I. One is the Pro Monitoring Program None Quarterly Monthly ity of life increases peometri*. gram Directive, which in Swrveillonca No Ye, Yes eallv above 0.5 ppm." structs regional and area per Medtel Record, No Y#s Ye, Turning now from general sonnel in how to conduct compliance inspections: it is intended to bring as much uniformity as possible to na Regulated Ar*o, Roster of Authorised Re-ton, Entering trjvloitd Areas No Ne No No 'te. Vs, principle* lo specific duties of employers in proeessing v i-r; plants, tbs new OSHA regula tion call* for the following ac 1; '/ :> tion* c enforcement of the Rcipirotor, No No Ye, tions in specified situations: standard. The other is a Sam Worning label, an Ye, Ye* Ye, Monitoring is required pling Data Sheet intended lo Storage Containers at least to determine initial instruct field personnel in a Training Yes Ym Ye, exposure levels. (Monitoring uniform method of sampling Oato supplied by Dlomond Shamrock Chemicol Corn. for VCM in air. This will done bcforeJan. 1 reportedly will be accepted.) Sinee moni- W- 1 ________________ I lli MliMit ImWi fr wl*dr r*fc i^ >Hwi mmih ir i mfr UM f l--ifim VCM MrM. Spring need not be coniinued for any ' employee whose exposure is found to be el or below the action level ("unless change* have been made in production, process, control, type of resin, etc/*), )OK what wiDutuun tutTuictii , .j- - monitoring remains an important question of Interpretation, at least until the Program Directive comes out Though this point Is interpreted by some to mean only one S-hr TWA determina tion per worker for a clean bin of health, this may not necessarily be so. Said one OSHA standards official, "Speaking as an Industrial hygienist. Tm not sure I would accept a single nm-through. At lea*t the points where highest exposures might be expected should be repeated." At any rate, in cases where above- action-level exposures are found, moni toring must be continued at least quar terly when below the permissible limit and at least monthly when above the limit, until two successive readings no less than five working days apart con firm exposures below the action level. Regulated areas must be cstabfished in processing plants wherever PVC ti "stored, handled or itscJ" and exposures exceed permissible limits. This means restricting access to "au thorized persons" ami keeping daily rosters of those entering the regulated areas. Su*h areas, which need not be physically wafted in. might comitt of the work space around a piece of proc essing equipment, as long as require ments for access control and keeping of rosters are met. Respiratory protection must he supplied if exposures exceed I- and 5- ppm limits. Though the employer must provide respirator? for ail who are thtts exposed, until Dec. 31.1975, em ployees may choose to forego such protection as long as exposures don't exceed 25 ppm (defined as a 15-min ceiling). Anyone choosing not to wear a respirator "shall be informed at least quarterly of the hazards of sinyl chlo ride and the purpose, proper use. and limitations of respiratory devices." Provisions for employee training about the hazards of VCM apply to all PVC processors, regardless of ex posure lesels at their plants. Compli ance officials offer no precise definition for any such a program: it could em ploy lectures, slides, demonstrations, pamphlets, etc. Where respirators are used, proper instruction in use and maintenance is required as per Scetion 1910.134 of OSHA regulations. Some review of the training program must be given annually. Medical surveillance of anyone exposed over the action level involve* a pecified yearl examination (or equivalent, as determined by a phy sician). provided at no cost to the worker. An OSHA-sponsored study by Foster D. Snell. Inc.. Flerhatr Park, ,v,l of survci. lance at St40-160'emplcyee. *cquir- ing a minimum of 1 Vi hr* of his time. It may be discontinued, as with moni toring. after exposures have been re duced below the action lesel. (A firm offering package medical program* specially tailored to this standard is Health F.valuaiion Programs. lnc,, Park Ridge. 111.) Containers of PVC resin--includ ing hags, boxes, loaded railcars, trucks and silos--and regulated areas mm! display specified signs or labels warn ing of a "cancer-suspect agent " All records of momtorinc. medi cal exams and rosters of persons enter ing regulated areas must be maintained for at least 30 years. Within a monrh after establishing a regulated area, reports must be sub mitted to your OSHA area director, citing plant location and rumher of emplmcvs in the regulated area. Each emplowe c\r-l.*d to more than per- nii*ih1c Ic'cU iwhcrhcr MCinn: a res pirator or not! must be informed in writing with n tO days of men taring results. A simplified ro'ter of employer dit ties rel ilcd to VCM levels ts presented in Tabic f. oppose Vest, find mil If son hnvr a problem With regard to monitoring--the first step toward compliance --industry ob servers note that a large proportion of processors arc already behindhand in Hus area. Not only have a good many pVC processors ignored the vinyl chlo ride monitoring requirement of tho , emergency temporary standard which has been in clTcct since April, but some*', have even indicated they will wait un til the last minute before confronting the situation. Of course, other processors has* more than met their obligations. For instance, one custom moldcr, Balt Flai-t tics Div.. Ball Corp.. Evansville, Ind., had been monitoring for the presence of organic vapors for several years be fore it recently began testing for VCM in particular. And several firms, par ticularly the larger ones, say they in tend to continue monitoring regularly even though they find no VCM expo sures in their plants amounting lb the action level. * By and large, those who have/toni- tored found they had little to fea. In terviews with companies in practically all areas of PVC processing--includ . #30 ing extrusion, calendering, inje iion, . blow and rotational molding--ins Icate many processors will find they have been operating with virtually und:tect- able levels all along. This is eonf.rmed by c-p.r.:r..: - ..^T*oi?n* laboratories. DeBell St Richardson "iS Texting Institute and Gollob Ar ilyti- 1 'i-.w-t cal Services, which monitored for vinyl h?2r. chloride in a total of about 50 PVC processing operations and founo few, major exposure problems that didn't seem correctable with improved venti lation. Mti This is not to say that common prob lem areas don't exist or that you ought not anticipate such and pay special attention to these aspects ** ~'*ur op eration. Experience has t>' *n what common sense would p ' '.ct: that highest exposures are penc/ally asso ciated with materials handling and storage and occur around hot-process ing equipment, particularly in the ease of intensive mixing units. Moreover, the chances of encountering unaccept able VCM levels can be related to whether one handles raw resin or com pound. powder or pellets, plasticized or iinplasiicircd material as discussed bc}pw. Wherever resin i,, stored ix a place to watch. According to Diamond Shamrock studies, area monitoring of trucks loaded ith resin showed levels above 15 ppm. air space in a bulk railcar after four days' storage meas ured over 4fi ppm and the inside of a silo. I ft above the resin surface, had more than 120 ppm. Granted that these were spot samples of areas wltcre :W.. OCCtMQCR 1974 R3V 0006638 't , > * I-*1 # .'rV'.n . 7!st:^ IIKI1 employee* cither don't work at alt or for ptdy short limes. you nonetheless shouM be alert to possible exposures of workers unloading a truck, sampling a .railcar, maintaining a silo (hist filter, and opening up bags or boxes of mate* : rW,>-., According to Oollob sources, poorly ventilated warehouses ean contain a few ppm, with some sites going as high as 29 ppm. The contribution to a work* er*a TWA would depend, of course, on the amount of time he spent near the atoned resin. Processing at elevated temperatures also tends to liberate residual mono* mer from the resin. Most experiments show that by far the greatest amounts Ml released during dryblending, and that relatively little is given off during subsequent extrusion, molding, etc. For example, investigators reportedly have found insignificant VCM levels right over extruder dies. An ! the Dia mond Shamrock data showed expo sures to operators of extruders, injec tion and blow raiding machines to be rarely above permissible or aetion leveK, while monitoring of mixing op- erati-ms indicated the need for much greater earn to avoid unacceptable level:. By this reasoning, processors han- counter less airborne monomer by an order of magnitude, especially if the comf ound has been produced by high- inten ity mixing. Rigid pellets, accordinr tt some sources, may release more VCV than powder compounds, de pending on how each was manufac tured Finally, flexible compounds, wheil-er powder or pellets, reportedly should give lower exposures than rigids. as the plastieixer is said to displace the monomer during compounding. Monitoring technique: no simple mat ter Probably no aspect of the VCM standard has amused more intense dis cussion than the monitoring technology itself. Considerable research and inno vation in analytical techniques have been fostered by the attention to this issue during the past year, and new equipment offerings have greatly ex panded the choices available. However, one of the biggest ques tions remains. What will satisfy OSHA? The standard requires only that "individual employee exposure levels be determined"; in fact. OSHA officii i say they mean m allow em ployers a certain amount of freedom tt to exact method of comntiance so lone as that Intent be fulfilled. (The Protram Directive should supply more information regarding criteria.) *0 The standard's preamble expressly permits both area and personal (or 'personnel") monitoring. Area moni toring of a xpc.iiiw plant location is said to offer the advantage of conveni ence; personnel monitoring o( actual breathing zones gives more direct de termination of the time-weighted av. eraget. in which the regulation is ex pressed. For instance, a I-ppm TWA could result from breathing exactly I ppm for 8 hrs. or 2 ppm for 4 hrs. or 4 ppm for 2 hrs; or it could mean, for ex ample. breathing 1.5 ppm for 4 hrs, followed by 0.5 pp.n for another 4 hrs. Some source* believe that area moni toring can give accurate determinations of TWA's without having the worker carry a personal monitoring device around with him for long periods. One way this might he done is by areamonitorng all work stations and then calculating by computer the amount of lime each worker spent in each loca tion. Another approach to figuring TWA fright V- to eamb'^e vea and personal monitoring. Th-t is. once personal monitoring had established exposure below the action level, area monitor ing could watchdog the operation to warn if exposure changed. Besides al.mng ~rr.zi:zU varr:rj zf high level excursions, as personal monitor ing does not. area monitoring has been determined by some company health liibti ar| Ni pail A-teU J. V-p-n Cn.| with tool tor officers to be f.r more economical over the long term with regard to mat* power requirements. Hlisl win OSIIA me? Tfcc VCM standard make* reference to only one' specific monitoring and analysis meth od. described by the National Instt-T lute for Occupational Safety and. Health in the NtOSft Manual of Analytical McthoJr. This method wifi be used by OSHA inspectors and is also the most widely employed in the* industry' to dale. A copy of the pro cedure. "Vinyl Chloride in Air" (P&CAM 41178). can 'he obtained from the NIOSH Office of Technical Publications in Cincinnati. The basic monitoring tool for this method is a personal sampling pump, a battery-powered device of the size and shape of a transistor radio, with a flexible tube attached (see photo, be .tlow). The pump draws nir in the flexi ble lube and through a glass lube con taining activated coconut-shell char coal used to adsorb any VCM present. Pumps w-cigh from as little at lOozup to about 2 lbs and may be earned in shirt pocket or dipped to a belt The end of the flexible tube it clipped someplace like the shirt collar to give a representative sampling of the breathing rent. To analyze monitoring results, the glass tube ix removed from the pump, th- charcoal emptied from the tube and shaken together with carbon distil? fide solvent to desorb the VCM. Then v-.h a sample of the CS-/VCM solution is run through a gas chromatograph, M' which separates the VCM from other chemicals present, to a flame ionlxa- ]!!. lion detector, which indicates how J>V- much VCM is present From the sam ple one can calculate the total amount' of VCM adsorbed by the charcoal from a fcnow-n volume of air (pump flow rate having been accurately cali brated) during a measured time period --thus obtaining a TWA. Though the NIOSH charcoal-tube method is only suggested and not re- >!> ouired. it has raised numerous ques tions and objections. One concerns the length of the sampling period deemed sufficient to establish an 8-hr TWA. Must one sample continuously for 8 hrs for each w-nrkcr. or would several shoricr sampling periods suffice? Industry ooininn on this point ranges from those who fed an 8-hf sampling give* the only definitive answer to ad vocate* of periods as short as 15 min, the latter stipulating of rnttrxe that sample* he made during timet of ex pect'd pc ik exposure. The NIOSH manual recommends a kr ci*fV RSV 0006639 PLASTICS TtCHNOLOGT ' jL'C: Gr> 'Tr'l-V'c. ft#, 'Ai - flow rate of 50 cc/niin, with & tout vWumc sampled nol lo exceed 5 f' liters for (he standard dwrcoal tube. ,1 - This recommendation is miulc in w -* der to avoid overloading the tube's ad* t fOlbent capacity, which would result Jt In false readings. At ihis flow rate, and \t with the normal range of sampling vol* X umc reportedly 1-5 liters, lubes must Jl _ be changed every 20* 100 min (1 liter % equalling 1000 cc). Thus, for practi* . ^ cality, a DcBdl it Richardson con* sultant recommends monitoring each worker for at least \\ hr even* 2 hn, or 4 tamplcs/shift. even though full . i. 6*hr monitoring might be theoretically preferable. ; But this same source says that inno- rations in pump design now permit '.i "a whole new philosophy of personal :? monitoring." Now that lower operat* ing ranges of pumps have recently *' dropped from 50 to as low as 5 cc/1 min, worker reportedly can me a single tube th'iH.jhout an entire shift. The consultant therefore recommends using pump with a suitable ipcrai- Ing range, for instance 10-50 ce/min. permitting full 8-hr monitoring with a few tubes at low flow rates; he also suggests taking a few short-time tarn* *!}j ;* *f* ftiirin* periods of expected peak exposure to satisfy the 5-ppm 15-min ceiling. Here, high flow rates would be better for maxi* mum accuracy since they concentrate as much VCM as possible on the char* coat Another stumbling block in inter* preting the monitoring provisions has been the requirement that whatever measurement used shall have a mini mum accuracy, "with a confidence level of 95#." of *50# at 0.23-0.5 ppm, 25# at O.M.O ppm and *25# over 1 ppm. The detection method offered in the NtOSH manual currently reads. "Pre cision; Unknown." but fuller evalua tion by NIOSH is reportedly due by lan. 1. OSHA says it will accept this method as meeting its accuracy re quirements--which the agency consid ers to he quite loose--and the unoffi cial word is that it will prove more accurate than called for. In any case, most observers ngrcc that the NIOSH method isn't for ama teurs. Among the various sources of error, or "interferences.** to which tha methou is reportedly subject arc b.uch- to-kil;h variations in charcoal. alTcct* Ing its adsorptive ansi ilesorptivc ctli- ctency. Ilih humidity is also said to be particularly had for accuracy. In exact ptrmp calibration is another source of error, as is contamination of tha carbon disulfide (itself a highly Table 2--VCM MOM JOKING ANI> ANALYSIS SI .RUCKS' Aetna t if* A Cavtty Co. Hanfcuit. Atrrn JnJuM'ul (,**. Marra* Mill. NJ. Andcrsnn.Stk.hnts. Iloston Roehringer I ahoraioocs, Wnneood. Pa. Chr.mctKS Liboumno, Ine, Park Riil^c, 111 Genres D. C1a>ion A Associates. Southfield. Mich. Cmhaueh t.jfw. Ct**l.id IXIMI A Richardson Icuing Institute, fn- fietj. Conn. Denser Research !mtimi*. I'niservtr of Denser. Denver Dunwid Shamrock Corp. Environmental l.aboralorirt, Pa:nc'tlle. Ohio Gollrb An.iUtical Service, Inc., Berktlry llexhis. NJ. Oitlf Roesrch A Devclrpment Co, Pitts- hurph LFK Corp., Environmental Anal>iJ< Like- ralories, Richmond. Calif. National I Control Scnice Corp.. Long Grose. III. Pollution Control Science, Inc, Miami*- btitg. Ohio Chatks M. SHarito A Son. Brooklyn. N.V. Ten Efh Emironmcntal CenuiUant*. South Pend. '* 1 t'n. erhjr of Cinci niti Medical Center, Kettcrinf Laboratory. Cincinnati US. Test in| Co.. Hoboken. NJ. Partial liitmt toxic chemical), besides numerous pos sible testing discrepancies on the pari of the laboratory analyst. A number of modifications of the NIOSH method have appeared recent ly. Scientists at Western Electric's Re search Center in Princeton. NT. d* velopcd a new rype of sampling tube containing porous polymer adsorbent in place of charcoal. Together with thermal desorption of the VCM. in stead of carbon disulfide extraction, the method is said to be one or two orders of magnitude more sensitive and is believed to be more accurate than charcoal tubes; also, the new tubes are reusable. Western Electric also uses a mass spectrometer, report edly givine the mosi pTtfTxe klcnufiration of VCM presence of any instru ment. though it costs n the neighborhood of $10Q fton. rv exp^o'l'v to op erate and requires highlv trained per sonnel. The comp.inv is said to he planning to |<ccn<c the new technology and an `improsed" area-monitoring method in thr nc.tr future Still another me I hod which has at tracted considerable attention is the use of rbstic bars instead of sampling littvs for perv.Mi.il niuniiuring. Now rtiat some pumps arc .itatlahlc which van be operated "i both a pressure and a suet-on n*.-v,te. they c.tn he u-ctl In fill a has with air simples n ICS of ..liim.ru/ed Mvljr. Tcdl.tr. Teflon and ur.in are said to have proved acceptable. They reportedly come in 1*7 liter tires and may be clipped to a belt or carried in a small knapsack. A 2/litcr bag measures about 8 x 16 x 2 in. thick when inflated. The bags require a septum for withdrawing _ a sample with a gas syringe or a valve which can be directly coupled to the gas chromatograph inlet port. Bag sampling is attractive for Its simplicity, because air ts merely col lected and then analyzed directly, there are fewer opportunities for error, and. whatever ge reading is obtained is an actual TWA for the contents of the bag. Some knowledgeable sources vouch for bag sampling as inherently more accurate than adsorbent tube methods. m Should yon buy equipment? Regard less of all the above considerations. . probably the main objection U the NtOSH method, from the pot; ( of view of a great many proeesso'S. Is that gas chromatographs are sopnisticaied instruments, generally costing several thousand dollars and at least requiring supervision by a tr lined analytical chemist. Numerous sir alter, simpler, less expensive versions of these and other types of instru nents . it w>ii| J.k.'t.xf- Th"- "tacfi?* turers claim to supply them full;' cali brated for push-button operatic A by relatively untrained personnel. But experienced technical pcrranncl at PVC resin companies tend 10 be skeptical of such claims, reasoning that analyzing for any gas in the range of Vi ppm involves considerable un certainties and that in ihe case of VCM. the stakes arc too high to permit a casual approach. Thus resin suppliers are generally cautioning their customers acainit hastily jumnirvg into large equipment purchases. They feci most processors won't be involved in monitoring over a long term. In fact, many fabricators mav find that they only need perform initial monitoring and very little there after. Most others should be able to get below the action level and stay ihere. Consequently, resin suppliers rec ommend ihat most processors begin hv consulting an independent analyli- cal laboratory (sec Table 2. above). Thce gioups provide various services, including complete monitoring and analysis, processing of samples taken hv the cu'tnmcr himself and equip ment rental. A spoi-eheck indicate* that fees commonly run $IO*.VVampie. depending on number and type of samnlcx. volume discounts being generally offered. Sti - 0CCCM0E* 1374 RSV 0006640 41 j .*-%<- ndWiduat needs wifi of course dif- te?TSmallcr processors have already shown some preference for otiiside .consultants, while larger operations, particularly those assncfaied with mhi producer or other technical-backup source, have installed sophisticated equipment systems. General Tire A . Rubber Co- for instance, has a $10,^ 000 pas chromatograph in each of its 12 PVC processing plants (used for a variety of purposes) and a mass spec trometer at its Akron research center. tA shopper's guide If you are consid',.i ering equipment purchases, you'll quickly find there's a bewildering array instruments now being advertised $to the plastics industry--end they cov er every level of price and sophistica'tJoti. f The following brief overview ci tome of the basic approaches to vinyl chloride detection and measurement provides an Indication c? costs and representative suppliers (see also Table 3, right): Persona! monitoring pumps. These, already discussed above, are offered for $300-350 bv such firms as Spin. $KC, Bendix, Mine Safety Ap pliances and Calibrated Instruments. Charcot! tubes, at 404 apiece, are available Iran SKC and other pump eupptie's as well as various distribu tors. Simpling bags may be obtained from Alliech Associates. Calibrated fmtrui tents and other pump suppliers. They e nt as much as $6 each but are reportedly reusable. Gss chromatography. Equip ment fcne encompasses a wide variety of tvp.s. from laboratory analytical models for anafyzint personal moni toring samples to on-line process moni tors for continuous sequential sam pling of one to 30 remote locations, as welt as units that combine both capabilities. Prices also range all over J'Vr.N ' the map. with large, sophisticated lab models seflin; for $5000-10.000 or jL more and simntified. portable units costing around SlOOO-SSOOfl. Suppliers include Perkm-Elmer, Hewlett-Pack ard. Vari.in. Beckman. Bendix. Gow. Mac Baseline Indiotries. Century Sys tems. Areas. Applied Automation, and Analytical Instrument Development. infrared absorption annfrsit. This technology has been attracting considerable attcr.: on as an alterna tive to gas chromatography for both personal and area monitoring. Units range from battery-powered portable types (under $3000) to computerized multipoint monitoring systems (SlO.000 and over). Two firms which have 'shown particular interest in VCM dc- Tahlc 3--VCM MONITORING and ANALYSIS I QUU*MENTStTI'UER9> A C.D.. lltC, CtlIC3|0 Altievh Aimum, AriiihiUn llrwhiv til. An.il)ii.-j| Instrument Dorlopnent, Inc, AonJjk, Pa Applied Automjiien, Inc, Dsnlntille, Oita Areas. Inc . Houston Bacharach Instrument Co. Pittsburgh U.ixtmc Injuarir*. Inc, L-ont, Colo. Beckman Instruments. Inc, Process Instru ments Hi. Fullerton, Calif. Beckman Instruments. Inc.. Scientific Irami* mentt Dt*, Irvine, Calif. Bendix Cutp, Environmental Science Dtv,, Baltimore Rendu Corp, Process Instrument Div, Rmcotnc. W. Va. E. D. Dullard Co, Sauutito. Calif. Byron .'n-tnimems. Inc, Raleiph, N.C. Calibrated {rmromenu. Inc, Ardtlc*. N Y. Carle lnstrun*ntt, Fullcnon. Calif. Century System Corp, Arkansas City. Kanv Drvco En-ineeilnc Inc, Fairfield, N.J Empire Technology Inc, Clifton Park- Elncra, N.V. rnviionmrM.il CimipluKr Corn, Pittsburgh IlnunsifiKMil Mri'Uicmrix Sjrwrms dtv. of Western Marine Eksirenks SeJUte F.iKom Ci-rp. Irvine, Calif. ift-mimrm Co, Madison, NJ. Hewlett-Packard, Avondale. Pa. Ilnneymrlt Inc, I'ruccM Analyrrr Cei/r, J leinlnfL ten Track Instruments, lac, Waltham, Mass. Matheson Gas Products. E. Rutherford. NJ. Alicrocbemieal Specialties Co, Berkeley, Calit MDA Scientific, Inc, Park Ridre. III. Mine Safety Appliances Co, Hiilsbargh Njtinn.il Environmental Insiroments, War wick. R.l. Prriin-Elmer Corp, Norvratk, Com. Anatole J. Xinn Co., N.Y.C. SKC Inc, Pitisburrh TC Systems. Ine, Itninion Vjrian Associates. Palo Alto. Calif. Wilks Scientific Corp- S. Norwalk, Coral. Paniil filling. teciio-s c Wilks Scientific and Eocom. Cuiorimetrlc methods. These ap pear to be another promising alterna tive. MDA Scientific has des'eloped several models that employ a chemi cally impregnated paper tape which changes color as VCM is drawn into she lamp.tng port. An optical sensor then measures concentration accord ing to depth of color change. System reportedly fitters extremely simple op eration and sensitivity to 0.01 ppm. Continuous area-monitoring unit with paper-tape cassette costs $2900 w-ith chart recorder; spot-sampling model is $500. MDA it also developing a personal monitor to be worn by work ers (S650 plus $950 for the tape reader); device will give both TWA and continuous profile of worker ex posure. For a simplified colorimetr'* approach to manual spot sampling. Bendix supplies glass tubes contain ing a reactive absorbent medium said to be highly specific to VCM. Sample from a hand pump is injected into a tube, with length of stain proJuced indicating coneentrsron. Mcihod re portedly can measure 0.5 ppm with iS-lO'T accuracy. (Cost s S85-90 for 10 tubes anj sampling pump ) Total hydrocarbon or organic rapor onw/yem. This approach to area monitoring, as the term suggests, isn'l specific to VCM and so is more suitable for showing where VCM doesn't exist than where ii docs. Sup pliers such as Hend x, fl.icharach and Century 5} stems provide unit* from portable direct-reading types to sta tionary. remote multipoint monitors. Prices range from around SfiOO to over $6000. Various other analytical approaches to portable and stationary area-moni toring are available. Examples include a detection system based on the d;ttering physiochemical adsorptive forces of different compounds, suoptied hr Environmental Measurement Systems; an electron-capture detect&r system from Ion Traek Instruments; systems from Devco Engineering based on identifying VCM by its dielectric con-* start, and an electrolytic-cel! gas sen sor from Bullard. (Prices vary with the unit.) But whichever way you decide to monitor, keep the OSHA inspector and the method he's using in mind. As a major PVC supplier puts it, "We want to be damn sure our results match up with his." What about respirators? Another** equipment question which has been causing some confusion is that of respirators. While it's hoped and ex pected that very few workers in proc essing plants will ever need to wear one. at least one informed Source doubts whether all purchasers of uncompotm.lcd resin will he able in the ihrri term to pet below permissible VCM hmtts in certain plant areas, mc'> .ii misirg rooms. Furthermore, a senior OSH \ oHical says that samp'ing of incoming railcars might well hr classified as a "hazardous opera tion"--defined, in pari, as a situa tion in which aceulcni.il overexposure* might reason.ihly occur--and thus re quire respiratory protection. One major qiustion concerns what 0006641 FUSTICS TlCrtftOlOCT r< At hr 01 wx.?' *-* }F r!\Wmi 15* *, ? ' * k*ilg D* * .W 4H; fW' ! * *rfl jga^tfe* Wat tlJTRtpf respirator b legal and practical The standard Iku specific tv pcs 'taptratar* as permissible in certain rjmmimof* VCM ambient concentra^IImn- the equipment for the higher :,-lf ktt b generally more expensive. ^ Italic type* Include: "y'f. u Air-purifying masks. which filter rA.'** ambient air through cartridge* or can- biers containing adsorbent media. Cartridge types reportedly run S10-12, ? eanntcrs about $50 and -powered" (Mower-equipped) type* around S200. ; Replacement cartridge! are S3-fi and cam $10-t$. Cartidge masks arc per mitted for up to 10 ppm and canisters for up to 25 ppm, probably as much as would be found in a processing plant Air-supplied masks, which arc fed through a hose from an outside source. Masks themselves cost $80-85: the kast expensive method rr supplying air would be to connect with the plant's compressed-air system and add a low.prewrr* purifier (about $1000). As issued, the standard permits air-line respirators without auxiliary supply in up to 100 ppm; but the list omits what's said to be actually the most common respirator type. The list is being amended so that, for not ever 1000 ppm. OSHA reportedly will perass*t#* w T^W fiiw#wln<4.nir pmsIiamaiic* Hour respirator with full or half mask, helmet or hood, which costs approxi mately $60*80. Self-contained compressed-air bot tles. which, depending on type, can be . uacd in all environments. For a 15-min supply, these units start at $350-100. Combination air-line types with selfcontained auxiliary supply would mn $200. However, to refill compressedair tanks requires a high-pressure puriftcr/compressor/cascade system cost ing S$000-S6000.* If any respirator is used at all. clear ly the most desirable for the processor In terms of cost and convenience of use arc the air-purifying types. Unfortu nately. to date no such respirators have been approved by NIOSH. as required by the standard. NIOSH reportedly Only just completed testing protocols to begin evaluations and possible cer tifications of respirators this month. One Important question still \ft hang ing is whether NIOSII ill msiq on cnd-of-scrvicc'lifc indicators (the first of which is only recently rumored to hk been developed! or mil go along with OSIlA's acceptance of "aJminhtralrvc controls** to make sure car tridges and canisters are replaced sulfi- eiently often. Dirt Of! if all approval* are ma<k* Immediately. H will l< impossible to ,-f KCtMKR 1974 V<r V>ft1 i ;Y CaO<i*x* ['.} *J cj-*tr )#.) *ypt '"-fmriiy-*? mpifiWi r last* **** and * t* **, bf mit wait NIOSH *ppral. supply the industry with the required number of respirators by Jan. I. ac cording to an SPI petition for a delay of the standard. Some 35 000 respira- m vrr reno-u-rllt* slfr*.Jy on order for VCM and PVC manufacturers alone, and SPI says today's supply h only 26fe of current demand: with ex peditious NIOSH approvals, suppl) would still be only TS ^ of demand. But shotiM lack of available respira tors be the only factor keeping you from compl.ance, OSHA sources in Washington say application fora vari ance is alwa>s a possible avenue of relief. Tips ow rnctnrrrJng controls When asked what diiliculiv processors will have in lowering VCM levels m their plants. mo*t informed sources replied that in the long mn. getting nd of VCM would not properly he the proc essor's problem at all. Since his only exposure to VCM can be from tinreactcd monomer in the resin (PVC doe* not degrade in \'CM). the mod evi dent solution is for the res.n supplier to remove as m.uh of it as possible. There is indeed a strong push hv all resin supplier* to accomplish just th.it. fe*m feporic.Vv m.iv contain jntwh.i; from lest t*v in I ppnt to over t *no pp"' of A C" M. il.-pen.lmg on mi'ii.*! of rn muf.Kture. j:t.idc. parti- t'e striKlurc .ind other fj.lors. The m.ti.d po.il. in!utry wule, teems to he to git averages hel*w 50 ppm; some supplier* v.y they can achieve thr* consistently in certain grades or from cenain production faeiliiiei TcmvecO -^: Chemicals even claims it has been able, on a pilot-plant basis, to product^ resin with "no detectable" VCM maimng. rtii. Meanwhile, the next best answer for the processor is said lo be :o remove'.,*, as much VCM as possible, under con trolled conditions, during .the eom*4. pounding process. Such an effort ^ would leave that much, less monomer to cause problems downstream. Sub stantial improvements m VCM remov- | al reportedly have been shown possible with a new technology developed .- >aj jointly by Id's Plastic* Div. and T. K. I Fielder Ltd. in England, with the tech- nology now made available in the.. ,^, US. and Canada through Werner A Fflcidercr Corp- Waldxick. NJ. The system centers on the drvblcnd- *ng cycle, where most VCM is nor mally generated, and further enhances this effect while insuring that the; VCM so produced is safely exhausted from the work area. Jn this way* it noi only makes the re*in more free of monomer for subsequent processing,, but rcporiefy also tend* to yield lower. , VCM level* in the mixer work area. ;!ri, Filtered air is cimtinuouxly aspirated through the mixer head-pace while' * small amount* of low-pressure air are ''[ also injected at or near the bottom of the mixer howl. This air then flows^ through the material, stripping away `v> additional VCM from the mix. Mono- mcr ladcn air is drawn from tlsc mixer -W? AK | 4) *X RSV 00066^2 through a eyetone separator. where large panicle* are collected in a re- ; mpvmMa dutt bin; k then move* on to a doth filler to trap addiiton.il fine* before passing through a turboblower Ad being exhausted from the work res. (Set diagram.) With this Exorsta system, much more monomer reportedly can be re mocd,-at lower temperatures than would otherwise be necessary. Com* parry data show that residual VCM in finished dryhlend can he halved by in* creasing mixing temperature from 250 F to 265 F. though even better results can be obtained at the lower tempera* lure by adding headspace aspiration alone* With air stripping as well, mwi* omer removal at 230 F is in* creased more than fourfold ajMo. Thus the system is said to readily produce drybtends with only 5*10 ppm residual VCM vs. more than 100 ppm by conventional dry*blending techniques* Werner It PAeiderer nrp* plies complete Laorsta sys tems, including engineering, train*ng and installation senr* Ices as welL The Exorsta sys tem i i a self-contained design with cyclone separator, Alter and exhaust mechanisms and is said to be readily adaptable to ret "oAtting all existing dry* blent units. It costs S3000600C installed, depending on C~al six* md type of mixing equipment Co isiderable work is being done in monomer-extraction techniques. Proc ess Control Corp, Atlanta, reports it also tas been retrofitting mixer unit* with its own aspiration systems. And Wetter ft Pfletdere. H developing techrology (or using vented twin-screw compounding extruders to remove even more monomer. A goat which it hopes to accomplish soon is to produce com pound with as little as 1 ppm residual VCM. Among other techniques for mini mixing VCM exposures In processing plants, automated bulk materials han dling is certainly a step in the right direction, as it criminates exposure from opening bag* or hose* or from stored material in warehouses. Out re member that what happens in a pneu matic feed line is reportedly something like air stripping in a miser; that is. there will he plenty of entrained mono mer and pos* Me leaks arc a facior to consider. Foe this reason, Process Control Corp. engineers have been recom mending vacuum rather than pressure systems. Pressure and friction report edly can make feed lines quite hoc 11X0-200 F) while vacuum lines are coider (100-120 I i and thus cause lest monomer to be released. What's more, Process Control's vacuum-conveying systems feature closed-loop designs that both cxhavM monomer outside the plant and reportedly avoiJ pamcic-size classification problems said to be com mon in closed-loop pressure systems. Process Control is working on other malcrials-handiing approaches m mini mize worker exposures in mixing areas. Here part of the problem is sa.d to be that uu.iIJy only maior com pound ingredicius (such as resin and plasticizer) arc metered automatically to the miser while from ms to 13 "microinffcdients" (additives which to gether add up to no more than 10'* of the total) are added by hand. The company recommends instead that these mieroingredients be masterbatched together with enough resin to dilute the whole to a sizeable volume from which portions could be auto matically dosed. Getting the operator away from the miser as much as pos sible is thus a simple answer to re ducing his exposure. But of all engineering controls ap plied to the VCM problem, ventilation is probably the most widespread and versatile. Moving large volume* of air to ventilate entire work areas is the most expensive anj least efficient afv proath; in aJJition. winter weather win require that incoming air be heat ed. at considerable extra expense. Locating exhaust hoods near proc essing equipment is bv far the pre ferred approach, and runs processors attribute their lack of exposure prob lems to doing this. In many cases, local ventilation had a'rcady been in stalled to remove plasticizer vapors and other fumes. (One plant even went to the nos cl length of entirely enclosing a calendering line.) I'rijvr ventilation is jKo advisable in warehouses where PVC resin rs stored. C*<wi anJ airflow requirements can pi*vthiy lx* minimized by keeping all FVC segregated in oe comer, per haps in an actual enclosure, with local exhausting pros ivied. Alternatively, in a warehouse with relatively pood over all air movement, you might scatter the PVC in smaller lots so that lesser local VCM concentrations could ac cumulate. Amount of ventilation needed in a warehouse will parity de pend on storage temperature, more monomer being liberated at higher temperatures. How long the resin b stored is also relevant: VCM emissions from haeged resin reportedly decline rapidly to negligible levels after a few weeks (though this is not necessar ily true for pelletized PVC materials). Some processors are spend ing several thousand dollars on ventilation in order to get below the aciion kvel. As this is a technically complex sub ject in itself, you may well want to consult a professional engineer before making such an investment Dr, Msurice Oberg of LFE Environmental Analysis Lab oratories presented some of the complexities involved at a recent SPE meeting in N.Y.C. For example, distance of an exhaust hood from the VCM source is an important factor, with airflow requirements increasing proportional ly to the square of that distance. Hood configuration is likewise important, since 25 Co less airflow reportedly can provide the same amount of control if the hood is flanged or if it's placed flush against a wall or other surface. One example Oberg cited was a hood over an extruder die. the hood flange contacting the die at roughly a 45* angle. Such an arrangement reportedly would provide efficient fume removal and avoid dripping condensed plasti cizer, for instance, on the extntdate, A flexible metal duct would permit the hex'd to be moved for access to the die. The above considerations, as well as shape of hood, fan blade configuration and duct geometry*, arc only some of ihc factors involved in designing the most efficient system for your money. (A professional manual on the subject is "lndiissn.il Ventilation.** published by the American Conference of Gov ernmental Industrial Hygienists Com- mutcc on Industrial Ventilation, Lan sing. Mich.) DO 44 PLASTICS TECHNOLOGY RSV 0006643