Document zQojVrQoBdgRZ7gw3EJrZyLo6

Li ( 3.) AN IN 3TRUMIS ITTAL SYSTEM FOR THE MONITORING OF VINYL CHLORIDE MONOMER IN PLANT AND LABORATORY WORK ENVIRONMENTS L. B. CRIDER January 1974 B.F.Goodrich Chemical Company Technical Center Avon Lake, Ohio 44012 AS I 00023317 Table of Contents Pa pp. Introduction ....................................................................................... Instrumental and System Requirements.......................... Instrument Selection and Evaluation .......................... Comparison ot Fixed Monitoring Instruments . . . Total Hydrocarbon Analyzer ......................................... Infrared and Gas Chromatograph Analyzers . . Combustion-Conductivity Analyzer .......................... 1 2 3 5 5 5 7 Comparison of Portable Survey Instruments .................................................... Portable Organic Vapor Analyzer........................................................................ Portable Gas Chromatograph .................................................................................. Portable Infrared Analyze'r.................................................................................. Portable Catalytic-Oxidation Analyzer . .................................................... 8 10 10 10 11 The Total, Instrumental Monitoring System......................................................... The Flame Ionization (OVA) Instrument ......................................................... The Automatic Sampling System .................... ..... .......................... Recorder and Data Collection ............................................................................. Fixed Station Monitoring Vs. Personal Monitoring .......................... 12 12 15 16 18 Summary .......................................................................................................................................... 19 Recommanlations ............................................................................ Acknowledgments AS I 00023318 21 21 Li Ml; of Tables, Figures and Appendices Table 1 Table 2 Tabic 3 Tablo s . . Portable and Fixed Monitoring Instruments . . . Comparison of Fixed Monitoring Instruments . . Comparison of Portable Survey Instruments . HlL 4 6 9 Figurus Figure 1 . . . Fixed Analyzer with Automatic Samp" Lng System . . Figure 2 . . . Fixed Analyzer Analytical Flow Description .... 13 14 Figure 3 . . . Data Collection System for Flame Ionization Instrument ................................................................................... . 17 Append ices Appendix I . . . Procedure for Start-up, Calibration and Use of Flame Ionization Fixed Analyzer .......................... Append ix II . . Procedure for Start-up, Calibration and Use of the Portable Organic Vapor Analyzer .... (Attached) (Attached) AS I 00023319 1 In trod uc L i on V.'i.thin the past several years there, has developed a growing awareness, of the need to do continuous or sequential sample monitoring of air quality in both Laboratory and production work areas. Significant factors contribut ing t (,j mir inc ron si-d knowledge relating to air quality in polynic riant ion buildings in the PVC industry Include the development of suitable instrument ation frr the analysis of contaminants and the implementation of these methods, initially on a batch sampling basis. The development of much improved monitor ing systems has lead to the ability to do continuous or sequential monitoring (as opposed to batch sampling) by interfacing an analytical instrument with an automatic sampling system. Additionally, the response signal from the analytical instrument now can be feed to a programmable calculator or mini computer t.o provide new reporting capabilities such as hourly and shift average concentration levels as well as an instantaneous display and recording of concentration levels at mu' pie locations. These much improved sample handling, analytical and data processing capabilities have revealed that the analysis of air quality based on infrequent, batch samples is grossly inadequate. It is also now apparent that oven the most advanced instrumental system is not totally adequate because of its limitations in monitoring only, from specific, fixed locations, whereas the monitoring needs may frequently be shifted from one location to another. The use of a fixed monitoring system, supplemented by the frequent use of easily portable analyzers having o.quivalent capabilities, is now 'recognized ns the minimum requirements for both monitoring and maintaining good air quality in polymerization work areas. AS I 00023320 2 As a result of this impr o vc d , a b i 111:y to moke sir quality measurements there has also dove luped an increased awareness of the many, complcxit ics involved in the maintenance of good air quality in an enclosed working area. Good vent i 1 a Lion, the rigid exclusion of leaks and the institution of improved manufacturing procedures are only n part of the practices that must be adhered to. Equally Important is the ability to provide early detection and to take immediate corrective action when contaminant levels exceed the criteria established for employee exposure. Obviously, a monitoring system must therefore be designed to meet the requirements of specific work areas. Preliminary studies must be made to determine excursion limits (maximum and minimum concentrations) of air pontaminants and a number of analytical methods must be considered or tested to provide the required measurements. Another important factor is the frequency of sampling and analysis required to provide early warning of high concentration levels and a suitable history of employee exposure. Equally important in the planning stage is proper consideration of data handling since continuous or rapid sequential monitoring from multiple sample locations can produce such a large quantity of data that some means of automated data acquisition, summation, averaging and report writing must be included as a part of the total system. Instrvimenf.nl and System Requirements An instrumental system for the monitoring of vinyl chloride monomer VCM) in a process or laboratory work area should have the following capabilities or characteristics; AS I 00023321 3 * One? ppm detection capabilities (or better), * Rapid response to changes in concentration levels, * Linear and reproducible response over a wide concentration range (0 - 1000 ppm), * Require a minimum of operator attention and maintenance, * Have the capability of sampling at multiple, remote locations. * Be compatible with a variety of sampling requirements and data handling methods-, such as interfacing to a multi-point recorder, programmable calculator or minicomputer. Other desirable1 characteristics of this system should include? low or moderate cost, the employment of simple, well accepted concepts and that the hardware and associated electronic equipment be compatible with existing operating and maintenance capabilities in our production plants. It also would be desirable that the instrumentation be of a type currently available from several instrument manufacLurers. Instrument Selection and Lvaluation AS I 00023322 Data obtained through the analysis of batch samples (using gas chromato graphy) and survey analyses (using a portable organic, vapor analyzer) are suffic ient to suggest that two different types of instrumental capabilities are required to meet all of the criteria for effective monitoring and rapid identification of emission sources. The utility of the portable organic vapor analyzer is already apparent in its ability to rapidly and very speci fically identify small leaks in processing equipment. It was an early con clusion that an eflcctive total system must include the capability to monitor with bo'h fixed and portable analyzers. The fixed analyzer should monitor a sufficient. mab.,1- of sample locations in a building so as to provide a continu ous na'oni con,ant rati on level l; and equally important provide early detection of concent ra t i one exceeding desired levels. When high VCM levels occurred, the portable uuulvaer would tb''a he <mp)uyed to more rapidly identify the source and p r 07 i do the suppl, mental capah i 1 i. L i or, needed for immediate corrective act i.mi. The scj'reninp, of methods having potential for meeting .all oi the required performance criteria resulted in a .select, list of instruments foi further testing, in a production plant, onvironmo lit: Table 1 Survey Instrum. n is (Portable) 1. Gas Chromatograph 2. Infrared w/20m gas cell Catalytic oxida 11oa 4. Flame Ionization* '^Organic Vapor Analyzer (OVA) Monitoring, Tnstruments (Fixed) L. Gas Chromatograph 2. Combus tion-Conductivity 3. Infrared w/20m ce.IL 4. Flame Ionization' Obviously, the above list includes a number of instruments that are now widely used for the monitoring of air quality. Some of these methods (infrared and gas chromatography) have specific component identifying capabilities and some (catalytic oxidation, flame ionization and combustion-conductivity) give a total response to hydrocarbons or halogens. In the early stages of in-plant testing oi these methods if soon became apparent that in a majority of PVC polymerization wo; 1; area;;, specific comp., nont identification was not required because the presence of atmospheric contaminants, other than VCM, was of little or no concern. Even in Loose areas where two or more components are present the AS I 00023323 requireunnC fur spec i fic cu:i!|H)iK'ut i.de nt i f i.c a t i u i.s n^.- - 'r L except in those c.j.si'.-; \;here thi're is a gross d i i I e re nee in the relative toxicity of the i nd ividue1 e i. imp one n L;; . Onpi>;i r i son o t F i xi '] Monitor! ng Instruments The following disoussion relating; to the evaluation of various typos of fixed analyzers for monitoring VCM, will be limited to r. general comparison of tlit' relative merits of the methods. Additional detail becomes unnecessary because of obvious, unreconcilnble problems involved in use of several ui the methods. A more concise summary of the advantages and dis advantages of !he various methods investigated is given in Table 2. Tota1 Hydrocnrhon Ana 1veer The use of a total hydrocarbon analyzer having a flame ionization detector is the preferred method for the monitoring of VCM with a fixed analyzer for several reasons; 1. Outstanding sensitivity (as low as 0 - 1 ppm full scale; 0.01 ppm minimum detection) 2. Linear response (2% full scale) 3. Goud reproducibility (j.-27 full scale) 4. Rapid response time (almost instantaneous) Additionally, the total hydrocarbon analyzer also fills the require ments for unattended --perati-.-n, minimum maintenance requirements and moderate cost (under $2,000 w/o recorder). Inf ran d end Gas Ch mm L orraph Analyzers AS I 00023324 Althoug.li the infrared and gas chromatographic methods are acceptable COMPARISON OF FIXED MONITORING INSTRUM -iUi s compared with the Total Hydrocarbon Analyzer inimum Detection Limit 7 in terms of many oL tin' desired performance features; they have the following disadvantages when compared to the total hydrocarbon analyzer; 1. Longer cycle time (2 - 10 minutes) 2. More complex equipment 3. More difficult to calibrate; operate and maintain 4. More expensive (2 to 3 times) The obvious advantage of infrared and gas chromatography is the ability to measure -''vcraL components in batch or sequential air samples. Comb us t: i nn-Conduc tivitv Analyzer Although the use of combustion-conductivity was considered as a candi date in the screening of possible acceptable methods; no direct investigation was made* to obtain comparative performance data for several reasons. No commercial instruments employing this conce.pt are now available. Also; this method lias been extensively explored and used by the Dow Chemical Company for the past ten years, based on Dow's evaluation^\ this method is a highly acceptable and usable procedure and fills many of the criteria for the monitor ing of VCM or other halogenated hydrocarbons in plant work areas. In comparing the combustion-conductivity method with the total hydrocarbon analyzer there are; however; a number of disadvantages; 1. It is a more complex system; 2. More difficult to operate and maintain; _>. More expensive, not commercially available. AS I 00023327 Dow Halogenated Hydrocarbon Analyzer"; Instruments boratory Report; The Dow Chemical Company; Midland; 8 111 summary, it can be said that the evaluation of candidate methods van limited in the type-.'; of hardware currently available fro:., a number of < instrument nimuiitictui.cn;. A suitable method was readily identified. No preference can be. stated for one instrument supplier over another. A primary objective in the screening evaluations was to identify a suitable instrumental method and to then expedite in-plant testing to finalize the design of a total system. The Bcndix 8401 Total Hydrocarbon Analyzer was the particular instrument selected for the in-plant testing phase,, al'hough similar instrumentation from another supplier could also he considered. Comparison of Pori able, Survey Instruments The screening of candidate method (summarized in Table 3) for use as a portable analyzer for VCM was largely influenced by prior, successful use of the flame ionization method as a portable monitor. It also soon became apparent that the comparisons relating to methods for fixed monitor ing were, in most cases, translatable to the portable monitoring evaluations. It should be emphasized that the most important features required in a portable VCM monitoring instrument are rapid response (almost instantaneous), outstanding sensitivity (1 ppm or better detection capabilities) and the equipment should be light weight and easy to handle and operate. Good linear ity over a wide range of concentrations and reproducibility are desirable features, although not as e.-itical as with the fixed monitor. Keep in mind that the major function of this instrument is to find leaks and emission sources :.. opposed to the continuous, quantitative requirements of the fixed analyzer. It also is desirable that the instrument be explosion proof or suitable for use in a Class I, Group D ar;a. 00023328 Method Organic Vapor Analyzer (OVA) vir' _la e ionization detector mCOMPARISON OF PORI SURVEY INSTRUMENTS Advantages of Method 1. Good sensitivity (low ppn) 2. linear response (1-1000 ppm) 3. Good reprcducibility 4. Rapid response (almost instantaneous) 5. Eight weight; easily portable 6. Easy to opera te and no into in 7. Moderate cost (<$3;000) Dissdvantac' s of Method 1. Nc_ :pacific for VCM 2. Not approved for use in a Class I, Group D work a: Gas Chromatography 1. Good sensitivity (Low ppm) 2. Acceptable response; good reproducibility 3. Specific for VCM 4 . Excel It.nt 'or multi-component mixtures Infrared Spectrometer v/20n Gas Cell 1. Excellent sensitivity [0.7 HDL'^] 2. Linear response; good reproducibility 3. Specific for VCM 4. Good for multi-component mixtures Catalytic Oxidation h>W-f o o w CO NS CD 1. Easily portable 2. Explosion proof 3. Good response at high concentrations (> \ as compared with the Organic Vapor Analyzer O'* Requires Hot Work Permit 1. Lacks instantaneous,respen for leak detection 2. Not as easily portable as 1. Lacks instantaneous resper for leak detection 2. Not easily portable 3. Not explosion proof; re eye i exclosure with N2 or ai: purge 1. Lacks sensitivity (not reliable below 50 ppm) 2. Bad zero level drift Organic Vapor Anal', aer (OVA) vir' flame ionization detector 1. Good sensitivity (low ppn) 2. linear response (L-1G0O ppm) 3. Good reproducibility 4. R20id response (almos t ins tantaneous) 5. Light weight; easily portable 6. Easy to operate and naintain 7. Moderate cost (<$3;000) Gas Chromatography 1. Good sensitivity (low ppm) 2. Acceptable response; good reproducibility 3. Specific for VCM 4 . Excel 1<_ nt ^r mul ti-component mixtures Infrared Spectrometer w/20m Gas Cell 1. Excellent sensitivity [0.7 MDL'^] 2. Linear response; good reproducibility 3. Specific for VCM 4. Good for multi-component mixtures .... . Catalytic Oxidation o>n 1--1 o rWss CWO o 1. Easily portable 2. Explosion proof 3. Good response at high concentrations as compared with the Organic Vapor Analyzer (2} Requires Hot Work Permit (3) Minimum Detection Limit Table 3 1. Go - ' c i f ic for VCM 2. Got approved for use in ; ^ 1 ' ^ ^ .i- , G a. U p Ll V, O . r. t 1. Lacks ins tantaneous re op: for leak -detection 2, Not as easily portable a. 1. Lacks ins tantaneons re sp. for lean Getection. 2. Not easily portable 3. Not explosion proof; rcq; exclosure with ^2 or a:' purge 1. Lacks sensitivity (not reliable below 50 ppm) 2. Bad zero level drift 10 P_o r ted gLih. (drib1 U 5 fb_Vn ;1or An:i ] yxc r The portable i` 1 i11;he Loniza ti on instrument (Century Organic Vapor Analyzer) gi von an almost instantaneous response to changes in VCM concen trations. It has excellent sensitivity (<1.0 ppm minimum detection limits) and gives a linear lcadout over a wide range of concentrations. The instru ment i.s light weight, compnet and easily transportable. T.t provides an excellent method 1 or the detection and location of small leaks in processing equipment. AlLhough the Century OVA is rated as being intrinsically safe for use in most PVC processing areas it has not yet been approved by Factory Mutual; m other rating agencies, for use in a Class I, Group D area. Such approval is expccLed however by mid-1974, Standard work practices involving the use of non-raLe equipment in such areas need to be rigidly adhered to (such as air testing and the issuing of a Hot Work Permit). portable Gqs Chromatograph The use of a portable gas chromatograph having a flame ionization detector has a number of distinct advantages including Inc ability to specifically separate and measure VCM in the presence of other organic vapors. Tills advantage, however, is responsible for several undesirable features of the method, namely increased analysis time and additional require ments for operation and calibration of the instrument. The inability to provide an almost instantaneous response is sufficient to preclude the gas chromatograph as an effective method for VCM leak detection. Its primary utility is in providing analysis of batch samples in work areas where multi component mixtures are present. Por La M i Infrared Analyzer AS I 00023331 .no infrared instrument (Wilkes Scientific Corp. Hi ran Gas Analyzer) u viil u-il.i'd nr a porL.'ihU1 VCM :m. l yze r had excellent sensitivity (0.7 ppm in i ii i ini'.in dr-LrcL i.im) . The in.jui; d i snd vs n t n gr s of (..hi:; method is Liu: lap, in response time (m'vhm! minutes) due to the '5 liter volume oi Lhe variable path leapt 1 i jp:; cell and the time required for flushing between samples. This limitation makes this method insensitive in rapidly detecting changes in VCM eoncentra i ions when the. snmpLe probe is moved from one location to another. The instrument is too bulky Lo conveniently use as a portable analyser. It also is not explosion proof. In the in-plant evaluation the instrument, was mounted in an air tight box and kept under a positive pressure using a Ng purge. This seriously 1 units the mobility of the instrument. It was also found that the housing for the detector is not light proof and that there is a change in zero level when the instrument was exposed to direct Portable Catalytic-Oxidation Analyzer The Catalytic Oxidation method (Bacharach Instrument Company's J-W Analyzer) did not meet our performance criteria for several reasons, the most important being lack of sensitivity (minimum detection limit of 10 ppm) and baseline (zero level) drift. The instrument is apparently responsive to temperature changes or other exposure conditions and over a relatively short period of time the tern level can change in amounts, equivalent to 100 ppm of VCM. In summary, it was concluded, based on the evaluation of these several methods, that flu- Organic Vapor Analyser equipped with a flame ionization toetor is the preferred type of instrumentation for use os a portable analyze, r for VCM in ambient air. AS I 00023332 12 The Totn 1 In;'. I r um_nla oring System A total ins Lrument.a L sysLem lor the monitoring of VCM in ambient air includes, in addition to the flume ionisation instrument, an automatic, multi-point gas sampling system, a multi-point recorder, and other means of data cm] lection such as a progranmsblo calculator or mini-computer and the necessary hardware for interfacing these components. A basic diagram of the instrument and sampling system is shown in Figure 1. The. Fla me Ton izn tiun Instrument., in a Fixed Monitoring System This unit is designed for unattended operation over long periods of time without the necessity for adjustment or any type of manual operation. The instrument is housed in a metal case sui.table for either bench or rack mounting (16-??" X Sp" X 18") and weighs approximately 40 pounds. The analyzer utilizes all solid state electronic components mounted on plug-in type printed circuit hoards. The utility requirements include a 115 volt power supply (150 watts) and a cyclinder of hydrogen for the operation of the burner in the analyzer. The hydrogen consumption rate is about 45cc/min. The* analyzer package (see Analytical Flow Description, Figure 2) includes an internal sample pump and sample pressure regulator as well as the nccosr.ui y cap II lui y flow controls and indicating pressure gauges to provide a very stable flow of hydrogen, air and sample gas. The analytical components in contact with the sample should be cither glass or stainless steel to minimize corrosion.. Some of the components in the flame ionization cell bonnet and guiderods) should be Teflon coated to prevent corrosion from the HC1 'woduccd from the combustion of VCM. AS I 00023333 Filters scism/o L --tx]-- L ROTOMETIk SURGE TANK --<x---------- F/ETER S G--d> SOLEROiQ 1 jtor&wFjx? i i 1 I \surge TANK SX- F/LTEXS Q--O pSOLE/JO10 --X3--1 Hz AtR \--; T'ClTZULAR 1--* S/S/ S r _ _ t---------------------------- 1 ] ^ PCTCPZOTEf Fly-PIT T fONSZAT/CN CELL ti J CAPILLARY F/LFER A j PUMP __\ roto/a etef HYCROCP.PRON /ASTp/RYT/JT 1 RECORDER o-/o a/rPuT calculator o-/ your output -IX XTEGAOE I WO-?ff CUT. pressure Q PEOULPTOR ~b -iX- BPrCAt PRESSURE PEG OLA TOP. BY PASS J \J&rOMTZG M> O L--cxoO Cs5 CO CO CO surge tank Zffl.0 A/R SPAR GPS CHARCOAL FILTER INSTRURlENT AYR Figure 1 Typical Aototyiat/c Sam.pl/ttg A\`0 TA/PLY2/NG 8PADIX SYSTEM FOR Amcizw VtL ArtALYTlCAL Flow DcLSCRIPT f qP PZD Clll 3/9 CK PR-5SUR. P\.GUi-/}TOR P/R IwL&r Luyb. PfLTLR ASI 00023335 P/ZB.5SURS. Pe^C,ULPTOR Qpuoa. o-/s psr -WSAAA-- Q, pi llary !Z" * .Of 7" Figure 2 This type of analyzer con operatic over a wide range of temperature and humidity conditions without ad verso of loot on measurement accuracy. The sample is introduced at a controlled rato into the flame ionization cell whore a hydrogen flame is burning in an atmosphere of air. As the sample enters tie.' flame a percentage of the molecules arc ionized, forming positive and negative tons. The extent of ionization depends on the compounds present (compos it ion and structure) and the temperature of the flame. As a general rule, compounds must have carbon-carbon or carbon-hydrogen bonds to be detect able. The degree of ionization Is roughly proportional to the number of carbon atoms per molecule. Inorganic materials such as hydrogen, oxygen, nitrogen and water are not ionized. The positive ions formed in the flame are collected on a negative electrode producing a signal that can be measured using the output of an electrometer preamplifier. The- Ati tom;; tic Sampli ng Systc m i'he interfacing of the automatic sampling sytem to the flame ionization instrument is shown schematically in Figure 1, including the manifold for the zero and span gas cylinders necessary for calibration of the instrument. It should be noted that sample pumps are included in both the analyzer and sampl ing system. The sampling system pump continuously pulls samples from six remote locations to the instrument inlet 'ran Hold. This reduces lag time to a few seconds. The sample valves are operated by a mechanical switching device in the multi-point recorder on a 2 minute cycle. The concentration level (ion current calibrated tor VCM) is recorded on the strip chart recorder and a suitable, signal is provided for a continuous digital read-out. Sample point", can be located up to 150 ft. from the instrument. The location 'ud number of sample points required should be determined by an AS I 0002333G 16 analysis of building ventilation patterns and many other factors including process equipment location:; that can result in VCli emissions and employee work area do fin >.ti ons . Sample points in employee work areas should be located at about breathing level (approximately 5 feet above the floor). The lines from the sample point to the sampling system manifolc * re 3/8" CD polypropylene tubing and contain two filters to prevent the introduction of polymer or dust into the sampling system or analyzer. The balance of the components in the sampling system are constructed of stainless steel. A one liter surge tank is included in each sample line. This addition was made to prevent the recording of rapid changes in concentration levels that apparently occur as a result of rapid vertical movement of thin VCM layers in the atmosphere. The surge tank provides sufficient mixing and compositing action (30 seconds) to smooth out the instrument and recorder response to these types of spikes. Recorder and Data Collection A variety of options are available for the collection and recording of data from the VCM analyzer system. The system shown schematically in Figure 3 is capable of handling a single analyzer with 6 sample points. This system consists of a six-point recorder,, a digital readout meter, digital clock and a 110 volt AC to 5 volt DC converter and other required hardware for interfacing to a programmable calculator (Wang Model 720C). gI qoo23337 Concentration levels are recorded by the 6-point recorder during each sampling cycle. Additionally, a signal is provided to the digital read-out mc-tcr and the programmable calculator. The calculator stores and averages data from each sample point to provide hourly and shift reports that are typed (2) This phenomenon is not completely understood. It suggests that transport of VCM in air may be much like the waving action of a heavy smoke. _/C3, f 7~^>' /YYy s\. - / - ^ ^ ^ -r / & ss S YS Y - -~ _ eX> /V / ~r 7^ / <~> /Y J~s '5 s~~ AT c/S<sf f~Z A/ ~7~~ 17 Figure 3 18 out on a u IBM typewriter. The hourly report is an average of concentration ^^^Levcls at each sample point in ppm. The shift report includes an 8 hour average of concentration level at each sample point plus a summary of maximum peak levels and time of occurrence for each hour during the shift period. The shift report also includes a summary of percent of time that VCM concentration level exceeded the maximum allowable concentration of 50 ppm. : Fixed Station Monitoring vs. Personal Monitoring ,,, 1 ; The use of fixed station monitors for the sampling and analysis of ambient air in a production plant is only one approach that can be used in ;,!'0 ! determining an employee s exposure index. The obvious disadvantage of fixed y V'T* station monitoring is its fixed nature as opposed to mobile personne1l.. ... --,y'.vr. Multiple station sampling capabilities are, therefore, essential to cove ' ' ':v<e \ ill of he areas of employee exposure. Additionally, the determination Of V-'.Y ^ '<" a a Time Weighted Average for an employee must include a calculation of con-, V':: centration vs. time to obtain a total exposure index. This accuracy of , this , .: method is obviously dependent on the ability to measure the concentration f ; .' levels in all areas of exposure and also to accurately estimate the amount . ei'Cym of time the employee spends in each work area. " :i,: '1 . J!, -i In comparing the use of a fixed station monitor with a personal monitor (a portable device worn by each individual) there are also some obvious advant- " X ages in display using the fixed station concept. Firstly, it of concentration level and obviously provides provides the best . an instantaneous '.ftl ' 4*> Hyi >dS;)y'Tys',f,it'`"A signal (alarm) for institut ing correcti'*- action. On the other hand, the personal monitor : iv\ provides only a history of events that are averaged out over a period of hours, ,yVH- ft,ost t_ -"3 of personal monitoring devices will only reveal an overexposure to AS I 00023339 ; a toxic substance after it has occurred. The fixed station monitor can warn you he fore overexposure occurs. The other obvious disadvantage of the personal ^^icnitor is that it must be vjorn by the Individual which can create problems due to bulk, weight, vibration or just because itrs a continuous reminder of ; the problem. A comparison of the costs of the two methods will, in general, :: show that a fixed station monitoring system will have an initially higher , hardware cost while the personal monitor will have a higher sustaining analytical cost, particularly when measurements are required for of employees. Although the evaluation of personal monitoring equipment was not a . .jg specific objective relating to the previously described instrumental:e uations, the need for this capability is now most obvious* The ultima , -V yv - V < ' j j **' evaluation of a fixed station monitoring system in measuring an emplbyee; xposure index must include some means of personal monitoring. The;acceptance of a fixed station system is dependent on obtaining reasonable agreement :witiv`$^^S data obtained from a personal monitoring program. Several methods of''persdnal^l^^ :' ' .'''V, I-S.1/. ' monitoring are detailed in the Iiterature O) (4) (5) t Each of these methodSjj-'h'i,v'i%i^||?i - ' ''Vvivt however, may require some further refinement or need to be modified to meet -. specific monitoring requirements in PVC production work areas. . S umma ry An analysis of the problems relating to the monitoring of vinyl chloride V|?m ljj|AS I 00023340 ('k) ' ` ^ ' A. A. Allemang and R. A Goudeau, ''Monitoring Personnel Exposure 'to ' \. J.. y, - 1 Chlorinated Hydrocarbons in an Industrial Work Environment", Persbhil Communicat j-ori, Dow Chemical Co., March 30, 1973. ." E. . Palmes and A. F. Gunnison, "Personal Monitoring Device for Guaassceouussv:;;j.^y:s4|:' Contaminants", J. of Arner. Xnd. Hyg. Assoc., pp. 78-81, Feb. 1973i'i'V^>'^i^ms- ^ Edward D. Barctta, et.al., "Monitoring Exposures to Vinyl Chloride Vapor: Breath Analysis and Continuous Air Sampling", J. of Ainer. Ind'. Hyc ' Assoc., Vol. 30, p. 537-544, Nov.-Dec., 1969. ; monomer (VCM) in laboratory and production work areas has shown that two different types of monitoring capabilities are required; a fixed analyzer with mill t i-poi nt remote sampling capabilities and a portable analyzer for rapid area survey analyses and leak detection. An evaluation of commercially available instrumental methods has revealed that the flame ionization method for monitoring low concentrations of VCM In ambient air has distinct advantages over other procedures invest igated. These advantages include outstanding sensitivity (0.01 ppm minimum detection); and good linearity and response (2%) over a wide range of con centrations (0 - 1000 ppm). Additionally; the analyzer is moderate in cost (approximately $2, 000) and can be easily interfaced to a multi-point sampling' system and continuously operated on a two minute per-sample-point cycle for long periods of time with a minimum of operator attention or maintonance. . A fixed monitoring system utilizing a flame ionization instrument ! 'Mi; ;\ \ ' p' ; (Bendix 8401 Total Hydrocarbon Analyzer) has been in continuous operation in: a PVC poly building; at the B.F.Goodrich Chemical Company plant in Avon Lake;>, Ohio; for approximately six months. This system which includes, in addition to the analyzer and a six point sampling system; a multi-point recorder, ' interfacing hardware and a programmable calculator for data reporting on a hourly and shift basis. The operation of this system has been essentially trouble free during this period and has provided the types of measurements required to determine VCM concentrations in a multi-story building and to .-V*. 'A Y' '0 '/V minimize employee exposure levels. . ' AV/-V An important adjunct to this system is the portable survey instrument that ha& outstanding utility in rapidly determining the source of VCM leaks : AS I 00023341 . in processing equipment. This instrument (Century Organic Vapor Analyzer^)) also uses the flame ionization principle. It is light weight, easily portable and has sensitivity find linear response roughly equivalent to the fixed analyzer. Equally important, and highly essential In leak detection, is this instrument's instant response to VCM. Re commendations The previously described evaluation of various instrumental methods /. . ` and the subsequent testing of a total system in a plant working environment g / has been sufficient to conclude that these, procedures can be easily applied.'' ef. to a variety of work areas where the monitoring of VCM in ambient air `is a <\ r , 1 ; 1 criteria for employee health and safety. It, therefore, can be recommended .m'rfVCSnJ1 that the identified methods, or their equivalent, be adopted as standard industry practices. Standard operating procedures detailing the start'pup,:^^ operation, calibration and instrument maintenance are included in Appendix ;Tv;, (Fixed Analyzer) and Appendix II (Portable Analyzer). V' , 'wh'&w A c.kn ow 1 e d gmo n t s V: The author would like to recognize the contributions of the large' ...i..-y?^ number of people who participated in this work. A particular debt of grati- , ' . 1- . , ' < '. ' - . . i'.`. .. fude is owed to L. W. Salzer for his wisdom in selecting specific instrumental * methods for testing; to M. D. Rider for his invaluable contributions to the in-:;M^ plant testing; and to H. E. Forsythe for his assistance in interfacing the analytical and data collection systems. (6) Ceii` ary Systems Corporation; Arkansas City, Kansas. r' " 1 -v; - v 1 ' ' ' - 1 , ! / ' ,t'P\ fy/ AS I 00023342