Document aBVR72ED6gZrVadmM2Q7qDGvX

AN INSTRUMENTAL 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 Table of Contents Pa Re Introduction ........................................................................................................................... I Instrumental and System Requirements ................................................................... 2 Instrument Selection and Evaluation ................................................................... 3 Comparison of Fixed Monitoring Instruments ...................................... .. 5 Total Hydrocarbon Analyzer ................................................................................. 5 Infrared and Gas Chromatograph Analyzers .......................................... 5 Combustion-Conductivity Analyzer ................................................................... 7 Comparison of Portable Survey Instruments ...................................................... 8 Portable Organic Vapor Analyzer .................................................................. 10 Portable Gas Chromatograph ........................................................................... 10 Portable Infrared Analyzer ........................................................................... 10 Portable Catalytic-OxidationAnalyzer ...................................................... d 11 The Total Instrumental Monitoring System .................................................... 12 The Flame Ionization (OVA) Instrument ......................................................... 12 The Automatic Sampling System ...................................................................... 15 Recorder and Data Collection...................................................................... 16 Fixed Station Monitoring Vs. Personal Monitoring ............................. 18 Summary ........................................... 19 Recommendations ................................................................................................................. 21 Acknowledgments 21 List of Tables. Figures and Appendices Table 1 Table 2 Table 3 Tables . . Portable and Fixed Monitoring Instruments . . . Comparison of Fixed Monitoring Instruments . . Comparison of Portable Survey Instruments . Pa ze 4 6 9 Figures Figure 1 . . . Fixed Analyzer with Automatic Sampling System . . 13 Figure 2 . . . Fixed Analyzer Analytical Flow Description .... 14 Figure 3 . . . Data Collection System for Flame Ionization Instrument................................................................................ 17 Appendices Append Lx I . . . Procedure for Start-up, Calibration and Use of Flame Ionization -Fixed Analyzer ........................ Appendix II . . Procedure for Start-up, Calibration and Use of the Portable Organic Vapor Analyzer .... (Attached) (Attached) Introduction 1 Within 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 to our increased knowledge relating to air quality in polymerization buildings in the PVC industry include the development of suitable instrumentationfor 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 to provide new reporting capabilities such as hourly and shift average concentration levels as well as an instantaneous display and recording of concentration levels at multiple 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 even 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 equivalent capabilities, is now recognized as the minimum requirements for both monitoring and maintaining good air quality in polymerization work areas. As a result of this improved ability to make air quality measurements there has also developed an increased awareness of the many complexities involved in the maintenance of good air quality in an enclosed working area. Good ventilation, the rigid exclusion of leaks and the institution of improved manufacturing procedures are only a 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 contaminants 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 nfonitoring 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. Instrumental 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; 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 desirable 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 manufacturers. Instrument Selection and Evaluation Data obtained through the analysis of batch samples (using gas chromato graphy) and survey analyses (using a portable organic vapor analyze!) are suffic ient to suggest that two different types of instrumental capabilities are required to ffieet 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 effective total system must include the capability to monitor with both fixed and portable analyzers. The fixed analyzer should monitor a 4 sufficient number of sample locations in a building so as to provide a continu ous record of concentration levels and equally important provide early detection of concentrations exceeding desired levels. When high VCM levels occurred, the oortable analyzer would then be employed to more rapidly identify the source and provide the supplemental capabilities needed for immediate corrective action. The screening of methods having potential for meeting all of the required performance criteria resulted in a select list of instruments for further testing in a production plant environment: Table 1 Survey Instruments (Portable) 1. Gas Chromatograph 2. Infrared w/20tn gas cell V Catalytic oxidation 4. Flame Ionization* *Organic Vapor Analyzer (OVA) Monitoring Instruments (Fixed) 1. Gas Chromatograph 2. Combustion-Conductivity 3. Infrared w/20m c^ll 4. Flame Ionization* Obviously, the above list includes a number of instruments thi at 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 of these methods it soon became apparent that in a majority of PVC polymerization work areas, specific component identification was not required because the presence of atmospheric contaminants, other than VCM, was of little or no concern. Even in those areas where two or more components are present the 5 requirement for specific component identification is not required except in those cases where there is a gross difference in the relative toxicity of the individual components. Comparison of Fixed Monitoring Instruments The following discussion relating to the evaluation of various types of fixed analyzers for monitoring VCM, will be limited to a general compar ison of the relative merits of the methods. Additional detail becomes unnecessary because of obvious, unreconcilable problems involved in use of several of the methods. A more concise sumaary of the advantages and dis advantages of the various methods investigated is given in Table 2. Total Hydrocarbon Analyzer 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 (27. full scale) 3. Good reproducibility (27. full scale) 4. Rapid response time (almost instantaneous) Additionally, the total hydrocarbon analyzer also fills the require ments for unattended operation, minimum maintenance requirements and moderate cost (under $2,000 w/o recorder). Infrared and Gas Chromatograph Analyzers Although the infrared and gas chromatographic methods are acceptable COMPARISON OF FIXED MONTTORING INSTRUMENTS Total Hyd* ocarbon Analyzer v: th Flame Ionization Detector 1. Outstanding sensitivity (0-1 ppm full scale) 2. Linear response (2% full scale) 3. Good reproducibility (27. full scale) 4. Rapid response time (almost instantaneous) and cycle time 5. Easy to operate, low maintenance requirements 6. Moderate cost ($2000 w/o recorder) 1. Not specific for VCM Gaa Chromatograph Infrared Spectrometer w/20m Gas Ceil 1. Good sensitivity (low ppm) 2. Acceptable response; good reproducibility 3. Specific J:or VCM 1. Excellent sensitivity [0.7 ppm MDL^^] 2. Acceptable response; good reproducibility 3. Specific for VCM 1. Longer cycle time (5-10 min.) 2. More complex equipment 3. More difficult to operate and maintain 4. More expensive 1. Longer cycle .time (5-10 min.) 2. More complex equipment 3. More difficult to operate and maintain 4. More expensive Combustion-Conductivity Method 1, Good sensitivity (low ppm) 2. Specific for halogens aa compared with the Total Hydrocarbon Analyzer Minimum Detection Limit 1. Not specific for VCM 2. Longer cycle time 3. Requires excessive operator attention and maintenance 4. Not commercially available GENC 000174 7 in terms of many of the 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 several components in batch or sequential air samples. Combustion-Conductivity 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 concept are now available. Also, this method has 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 fiJlls 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 s are, however, a number of disadvantages; 1. It is a more complex system, 2. More difficult to operate and maintain, 3. More expensive; not commercially available. Ray, ond M. Donahue, "Dow Halogenated Hydrocarbon Analyzer", Instruments Systems Research Laboratory Report, The Dow Chemical Company, Midland, Michigan. ''J 8 In summary, it can be said that the evaluation of candidate methods was limited to the types of hardware currently available from a number of instrument manufacturers. 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 Bendix 8401 Total Hydrocarbon Analyzer was the particular instrument selected for the in-plant testing phase, although similar instrumentation from another supplier could also be considered. Comparison of Portable. Survey Instruments The screening of candidate methods (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 critical as with the fixed monitor. Keep in mind that the major function of this instrument is to find leaks and emission sources c. 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 area. Hothod Organic Vapor Analyzer (OVA) wir\ flame ionization detector COMPARISON OF PORTABL! RVEY INSTRUMENTS 1. Good sensitivity (low ppm) 2. linear response (1-1000 ppm) 3. Good reproducibility 4. Rapid response (almost instantaneous) 5. Light weight; easily portable 6. Easy to operate and maintain 7. Moderate cost (<$3,000) Disadvantages of Method (1) 1. Not specific for VCM 2. Not approved for use in a Class Ij Group D work ares'- Gas Chromatography Infrared Spectrometer w/20m Gas Cell 1. Good sensitivity (low ppm) 2. Acceptable response; good reproducibility 3. Specific for VCM 4. Excellent for multi-component mixtures 1. Excellent sensitivity [0,7 MDL^^] 2. Linear response; good reproducibility 3. Specific for VCM 4. Good for multi-component mixtures Catalytic Oxidation 1. Easily portable 2. Explosion proof 3. Good response at high concentrations as compared with the Organic Vapor Analyzer ^ Requires Rot Work Permit Minimum Detection Limit Table 3 1. Lacks instantaneous response for leak detection 2. Not as easily portable as OVA 1. Lacks instantaneous response for leak detection 2. Not easily portable 3. Not explosion proof; requires exclosure with N2 or air purge 1, Lacks sensitivity (not reliable below 50 ppm) 2. Bad zero level drift \D GE^C OOOj-- 10 Portable Organic Vapor Analyzer The portable flame ionization instrument (Century Organic Vapor Analyzer) gives an almost instantaneous response to changes in VCM concen trations, It has excellent sensitivity (<1.0 ppm minimum detection limits) and gives a linear readout over a wide range of concentrations. The instru ment is light weight, compact and easily transportable. It provides an excellent method for the detection and location of small leaks in processing equipment. Although the Century OVA is rated as being intrinsically safe * for use ir\ most PVC processing areas it has not yet been approved by Factory Mutual, or other rating agencies, for use in a Class 1, Group D area. Such approval is expected however by mid-1974. Standard work practices involving the use of non-rate equipment in such areas need to be rigidly adhered to (such as air testing and the issuing of a Hot Work Permit). Portable Gas Chromatograph The use of a portable gas chromatograph having a flame ionization detector has a number of distinct advantages including the ability to specifically separate and measure VCM In the presence of other organic vapors. This 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 multicomponent mixtures are present. Portabis Infrared Analyzer The infrared instrument (Wilkes Scientific Corp. Miran Gas Analyzer) Gtf'j; i 11 evaluated as a portable VCM analyzer had excellent sensitivity (0.7 ppm minimum detection). The major disadvantages of this method is the lag in response time (several minutes) due to the 5 liter volume of the variable path length gas cell and the time required for flushing between samples. This limitation makes this method insensitive in rapidly detecting changes in VCM concentrations when the sample probe la moved from one location to another. The instrument is too bulky to conveniently use as a portable analyzer. 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 N2 purge. This seriously limits 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 sunlight. 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 zero 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 the Organic Vapor Analyzer equipped with a flame ionization detector is the preferred type of instrumentation for use as a portable analyzer for VCM in ambient air. &ENL COOl^v 12 The Total Instrumental Monitoring System A total instrumental system for the monitoring of VCM in ambient air includes, in addition to the flame ionization instrument, an automatic, multi-point gas sampling system, a multi-point recorder, and other means of data collection such as a programmable 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 Flame Ionization 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 suitable for either bench or rack mounting (16^" X 8^" X 18") and weighs approximately AO pounds. The analyzer utilizes all solid state electronic components mounted on plug-in type printed circuit boards. 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 necessary capillary 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 either 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 'roduced from the combustion of VCM. Filters EOlEAJO/O o--o II k RotoMeritL suroe TANK --tX]-------- F/UEAi --o SOLEHOLD u lieu tometsR 5UR.6E TANK I--tXh p/ltexs J----------------- SOL lAJOtO 1 TTOMETtR SUROE tank --X3- txj--. I-txj- FILTER Hi AIR MOtECULAR s/ere drjers vwr r1 FLAME \ f&TOMcreR 1 iOWEA T/ ON CELL t o sz | PUMP rotomitea CAPILLARY HYDROCARBON /HSTRUMEHT 1 RECORDER 10-/o mv ct/rf\>T CALCULATOR 0-1 VOLT OUTPUT -xj IK3oOM-Wf* 0*. V-# PRESSURE ** REGULATOR. BACK PRESSORE REGULATOR BY PASS J nZEAO AIR SPAM GAS CHARCOAL PUTZR INSTRUMENT A/R Typical Automatic Sampumg RFO fiHALYTtNG BFHDZX SYSTEM FOR /Qmbieut VCL Figure 1 liENC 00019i u> Analytical Flow Description FID Cell Figure 2 GfNC onnt. This type of analyzer can operate over a wide range of temperature and humidity conditions without adverse effect on measurement accuracy. The sample is introduced at a controlled rate into the flame iopization cell where a hydrogen flame is burning in an atmosphere of air. As the sample enters the flame a percentage of the molecules are ionized, forming positive and negative ions. The extent of ionization depends on the compounds present (composition and structure) and the temperature of the flame. As a general rule, compounds mu3t 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 Automatic Sampling System The 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 art# included in both the analyzer and sampl ing system. The sampling system pump continuously pulls samples from six remote locations to the instrument inlet manifold. 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 for VCM) is recorded on the strip chart recorder and a suitable signal is provided for a continuous digital read-out. Sample points can be located up to 150 ft- from the instrument. The location and number of sample points required should be determined by an 16 analysis of building ventilation patterns and many other factors including process equipment locations that can result in VCM emissions -and employee work area definitions. 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 manifold are 3/8" OD 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 72QC). Concentration levels are recorded by the 6-point recorder during each sampling cycle. Additionally, a signal is provided to the digital read-out meter 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. ZZZ-? 7"/*? ?&*-1. &,~r/ a yv -S'x_s~ Tis^f /crz.s4s*f<1 JT'/S 7'/ZU^f&AT-7- 17 Figure 3 18 out on on IBM typewriter. The hourly report is an average of concentration, levels 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 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 determining an employee's exposure index. The obvious disadvantage of fixed station monitoring is its fixed nature as opposed to mobile personnel. Multiple station sampling capabilities are, therefore, essential to cover all of che areas of employee exposure. Additionally, the determination of a Time Weighted Average for an employee must include a calculation of con centration vs. time to obtain a total exposure index. This accuracy of this method is obviously dependent on the ability to measure the concentration levels in all areas of exposure and also to accurately estimate the amount of time the employee spends in each work area. 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 ages in using the fixed station concept. Firstly, it provides an instantaneous display of concentration level and obviously provides the best signal (alarm) for instituting corrective action. On the other hand, the personal monitor provides only a history of events that are averaged out over a period of hours. Most t) -^3 of personal monitoring devices will only reveal an overexposure to 19 a toxic substance after it has occurred. The fixed station monitor can warn you be fore overexposure occurs. The other obvious disadvantage of the personal monitor is that it must be worn by the individual which can create problems due to bulk, weight, vibration or just because it's 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 large numbers of employees. Although the evaluation of personal monitoring equipment was not a specific objective relating to the previously described instrumental eval uations, the need for this capability is now most obvious. The ultimate evaluation of a fixed station monitoring system in measuring an employee's exposure index must include some means of personal monitoring. The acceptance of a fixed station system is dependent on obtaining reasonable agreement with data obtained from a personal monitoring program. Several methods of personal monitoring are detailed in the literature (5). Each of these methods, however, may require some further refinement or need to be modified to meet specific monitoring requirements in PVC production work areas. Summary An analysis of the problems relating to the monitoring of vinyl chloride (3) A. A. Allemang and R. A. Goudeau, "Monitoring Personnel Exposure to Chlorinated Hydrocarbons in an Industrial Work Environment", Personal Communication, Dow Chemical Co., March 30, 1973. (4) E. . . Palmes and A. F. Gunnison, "Personal Monitoring Device for Gaseous Contaminants", J. of Amer. Ind. Hyg. Assoc., pp. 78-81, Feb. 1973. Edward D. Baretta, et.al., "Monitoring Exposures to Vinyl Chloride Vapor: Breath Analysis and Continuous Air Sampling", J. of Amer. Ind. Hyg. Assoc., Vol. 30, p. 537-54-4, Nov.-Dec., 1969. 20 monomer (VCM) in laboratory and production work areas has shown that two different types of monitoring capabilities are required; a fixed analyzer with multi-point 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 $2,0G0) and can be easily interfaced to a multi-point sampling system and continuously operated on a two minute per-saraple-point cycle for long pe-iods of time with a minimum of operator attention or maintenance. A fixed monitoring system utilizing a flame ionization instrument (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 minimize employee exposure levels. An important adjunct to this system is the portable survey instrument that has outstanding utility in rapidly determining the source of VCM leaks 21 in processing equipment. This instrument (Century Organic Vapor Analyzer^^) also uses the flame ionization principle. It is light weight, easily portable and has sensitivity and linear response roughly equivalent to the fixed analyzer. Equally important, and highly essential in leak detection, is this instrument's instant response to VCM. Reconroendations The previously described evaluation of various instrumental methods and the subsequent testing of a total system in a plant working environment has been sufficient to conclude that these procedures can be easily applied to a variety of work areas where the monitoring of VCM in ambient air is a criteria for employee health and safety. It, therefore, can be recommended that the identified methods, or their equivalent, be adopted as standard industry practices. Standard operating procedures detailing the start-up, operation, calibration and instrument maintenance are included in Appendix I (Fixed Analyzer) and Appendix II (Portable Analyzer). * Acknowledgments The author would like to recognize the contributions of the large number of people who participated in this work. A particular debt of grati tude 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 in1 plant testing; and to M. E. Torsythe for his assistance in interfacing the analytical and data collection systems. (6) Cen" try Systems Corporation; Arkansas City, Kansas. B.F.Goodrich Chemical Company Avon Lake General Chemical Plant Avon Lake, Ohio STANDARD OPERATING PROCEDURE Bendix Total Hydrocarbon AnalyzerI. 2 3 4 I. Scope This procedure is a method for the determination of vinyl chloride in air by the hydrogen flame ionization method. II. Discussion The vinyl chloride content of the building air shall be determined to comply with the company criteria for maximum allowable exposure of 50 ppm. The sample is introduced into the Flame Ionization Detector (FID) cell under pressure where a hydrogen flame is burning in an atmosphere of air. The resulting burning of the sample produces an electrical output signal which is proportional to the amount of hydro carbon (vinyl chloride) in the sample. The output voltage is then indicated on the output meter, recorder and calculator. Ill. Safety 1. The Bendix TEA and recorder ere non-explosion proof, therefore, requiring installation in a control room or warehouse area. 2. Hydrogen gas, when mixed with air, is highly flammable. Avoid any sparking conditions during cylinder changes. Do not disconnect hydrogen lines with open fires in the area. 3. Do not attempt to remove the FID cell until certain that it has cooled sufficiently to,prevent burns to personnel. 4. Do not remove or replace electronic cards with power on. Use care to avoid personal contact with electrical contacts while the instru ment or recorder is operating. Date issued: January 28, 1974 By: M, D. Rider Bendix Total Hydrocarbon Analyzer Issue 1 Page 2 of 8 1-28-7U 5. Installations of sample probes five feet from the floor level should be placed in non-critical path areas avoiding personnel contact. XV. Startup Procedure Prior to 'Performing the startup procedure, ensure that the POWER switch, and SUPPHSSON switch are in the OFF positions and the ATTENUATION switch is set to X10. To perform system startup, complete th& following tasks In the sequence indicated; 1. Adjust charcoal filtered instrument air to a nominal 25 psig setting. 2. Adjust the hydrogen cylinder output pressure to a nominal 25 psig setting. 3. Adjust the hydrogen pressure on the Bendix front panel to a nominal 5 psig setting. U. Adjust the air-pressure on the Bendix front panel to a nominal 6 psig sett-ng. 5. Turn POWER switch ON. 6. Place the Ignitor switch in the IGNITE position. Hold the switch in this position until the flame out light goes off. If the flame out light comes on again, place the switch in the.IGNITE position again and hold for a long period of time. V. Setting Instrument Zero1 2 At initial startup, or following extended periods of non-operation, the instrument zero must be cot prior to calibration and operation. In these eases perform the startup procedure and allow the instrument to operate for a minimum of 60 minutes to allow the system to stabilize. After instrument stabilization or if the unit has been in operation and a routine zero check is being made, proceed as follows: NOTE: First take Wang calculator off line by pressing PRIME. 1. Open the activated carbon filtered instrument air by-pass line and assure a maximum pressure of ?8 oz. pressure using the Watts pressure regulator. CAUTION; Excessive pressure to the analyzer pump will rupture the pump bellows. 2. Ope" the AIR valve & close MAIN SAMPUS SHUT OFF valve simultaneously on the bendix automatic sampling system. Bendix Total Hydrocarbon Analyzer Issue 1 Page 3 of 8 1-28-74 3. When the output meter on the Bendix front panel has stabilized, unlock the SUPPRESSION control knob and adjust to zero. The ATTENUATION switch is set to XI for zeroing. An acceptable zero is in the 0 to 0.05 ppra range on the output meter. 'yi/OOO 4. c-et the ATTENUATOR knob to recorder. and assure a zero reading on the 6 point 5. Shut off the filtered instrument air bypass line. 6. Close the AIR valve and open tho MAIN SAMPLE SHUTOFF valve simultaneously on the Bendix automatic sampling system. VI. Calibration 1. Open the vinyl chloride in air (110 ppm) compressed gas cylinder valve. 2. Adjust the 2 stage gas regulator to a nominal 25 psig setting. > 3. Open the VC1 gas shutoff valve and assure a maximum pressure of 28 oz. pressure using the Watts pressure regulator. 4. Open the VC1 valve and close the MAIN SAMPLE SHUTOFF valve simultaneously on the Bendix automatic sampling system. 5. when the output meter has stabilized, unlock the RANGE knob and adjust the output meter to read a nominal 2ft^The recorder reading should be set exactly to read The ATTENUATOR has been previously set at K'jOfl for a 110 ppm standard.,l0 X/oJV 6. Shut off the vinyl chloride compressed gas cylinder valve. 7. Close the VC1 valve and open the MAIN SAMPLE SHUTOFF valve simultaneously on the Bendix automatic sampling system. VTI. On Stream Analysis 1. Set ATTENUATION knob to X1000. .2 Assure the 6 rotameters are equally balanced at 4 LFM 3- Press GO on the Wang calculator. GEtiC 000 WI 4. Ho'e calibration on Wang typewriter printout, L & N recorder, and log sheet, Al. 1. note hydrogen gas cylinder pressure, suppression setting, range setting, and the Bendix pump bypass flowmeter reading on the log sheet. Weekly zero and calibration checks are required. 5* Presently O-^OO ppm data is displayed on the L & N recorder and 0-1000 ppm data is dit played on the Wur.g r^ '; -r typewriter. Bendix Total Hydrocarbon Analyzer Issue 1 Page U of. 8 1-28-74 VIII. Complete Shutdown Procedure 1. Push PRIME on the Vang calculator. 2. Move Bendix THA POWER switch to the OFF position. 3* Close the AIR SUPPLY shutoff valve. 4. Move Bendix sampling system pump switch to the OFF position. 5. Move the recorder power switch to the OFF position. 6. Remove top fuse inside recorder to deactivate solenoid mechanism. IX. Routine Maintenance 1. Clean in-line Hoke filters and the $' Swagelok filter in the sample line if the bypass flow meter reads less than l.J LPM. 2. Replace the MSA sample inlet filter cartridge once every six months. 3* Replace the activated carbon filter on the instrument air supply once every 6 months or if the suppression setting approaches 800. 4. Replace the hydrogen gaG cylinder supply when cylinder pressure declines to 100 psig. A full cylinder has an approximate 4| month service life. 5* Molecular sieve driers on the hydrogen and air lines ohcwld be dried in an oven at 105"C. for 4 hours every six months to drive off the moisture. 6, Replace the chart paper on the recorder once every 2^ weeks. 7. Replace the ink pad wheel on the recorder when the readout becomes faint. Depressing the ink pad with a sharp point may bring additional ink to the pad surface. X. Hydrogen Cylinder Replacement1 2 3 4 1. Push the PRIME button on the Wang calculator. 2. Move the Bendix POWER switch to the OFF position. 3. Close the hydrogen cylinder valve. 4. Tu..i the two-stage regulator fully counter clockwise and remove the regulator from the cylinder. bEi-lL 0001 Bendix Total Hydrocarbon Analyzer Issue 1 Page 5 of 8 1-28-7**. 5. Slightly open and close the new hydrogen gas cylinder valve to blow out foreign particles. 6. Connect the new cylinder to the regulator (left hand threads). 7. Open the cylinder valve- and adjust the two-Btage regulator for a pressure of 25 pslg. 8. Turn instrument power ON. 9. Assure hydrogen pressure gauge on the Bendix front panel read* a nominal 5 psig- 10. Allow a minimum of 10 minutes for air to purge from the system and ignite the flame. 11. Perform the zero and calibration procedure 10 minutes after the instrument has come to equilibrium. 'Refer to Sections V, VI, and VTI. XI. Trouble Shooting Refer to the attached Trouble Analysis Chart. If a malfunction is suspected and all controls appear to be operating properly, refer to the Service Manual for the trouble shooting and repair procedures. The procedures contained in the Service Manual are designed for use of technically qualified personnel only. The use of the manual by unqualified or inexperienced personnel is not recommended. The Total Hydrocarbon Analyzer is a precision instrument and can be damaged by improper handling and maintenance. This abo\e statement also applies to the L & N Speedomax "H" recorder. XII Reference Bendix Series 81*00 Total Hydrocarbon Analyzer Installation and Operation Manual. Bendix Series 8400 Total Hydrocarbon Analyzer Service and Maintenance Manual. L h N Speedomax H & W Multipoint Recorder Manual, Directions 17730k* Issue 7> and Addendum to Directions 17730k, Issue 7* Bendix Total Hydrocarbon Analyzer Issue 1 XIII. For Service & Technical Information Contact Clay Cook Ext. 277 Electrical & Instrument Foreman Doug Kider Ext. 554 or 553 Environmental Engineer Lou Saizer Ext. 297 Process Instrument Consultant Mark Forsythe Ext. 485 Electrical and Electronics Engineer bp * Page 6 of 8 1-28-7^ bEt' Page T of 8 Symptom Panel meter fail* to indicate. Excessive meter noise. Flame out light illuminated. Sample pressure gjuge indicate* rero pressure. Table 2-1. Trouble Analysis Chart Probable Cause Corrective Action Power cord disconnected. Connect power cord. Blown fuse. Replace fuse. Power switch is OFF. Turn power ON. Electrometer card inopera* tive. Power supply card inoperative. Replace electrometer card. Replace supply card. Def<p:tive meter. Replace meter. Contaminated hydrogen. Contaminated air. Replace H} cylinder, Replace air cylinder. Moisture in FID cell. Ensure that temperature is et least 8Q*C. Defective power supply card. Replace supply cerd. Leak in H, or air rystem. Repair leak. Defective coaxial cable, r Excessive variation in ac supply. Replace cable. Obtain correct supply source. Weld joint on collector is broken. Replaca collector. H, or air supply depleted. Replace as necessary. Defective Hj thuioff solenoid. Replace solenoid coil or solenoid as required. Excessive sample flow. Correct to flow rate specified in Operational Data Sheet. Plugged capillary. Replace capillary. Check filters end replace ell that are dirty or dogged. Inoperative pump. Replace pump. Plugged filter. Replace or deen filter. Ci hi 1C 1 Sample lnlt 2 Pump, High Tempereture 3 Cell Vent 4 Bypass 5 H, Inlet 6 Air Inlet 7 Fen 8 Filter Card 9 15 VDC Power Supply Cord 10 Converter Card 11 Auto Ignitor Card 12 110 VDC Power Supply Card 13 Resistor Card 14 Resistor, 1 x 10w (1,000,000 Meg) 15 Capacitor, 22 PF 16 Resistor, 1 x 10' (10,000 Meg) 17 Microdot Connector (tji card) 18 Air Valve & Indicator 19 Fuel (Hj) Valve & Indicator 20 Meter 21 Sample Valve 22 Sample Pressure Indicator 23 Heat Shield 24 Pump Motor 25 Cell Page 8 of 8 Symptom Probable Cause Corrective Action H, pressure gauge indicates zero pressure. Incorrect pressure, !> Hydrogen Generator is off or cylinder is depleted. Set pressure to conform to setting specified in Operational Data Sheet. Turn on generator or replace cylinder. Defective pressure regulator. Replace regulator. Air pressure gauge indicates I9t0 prVK^*s Total hydrocarbon measurements are aPncrmaily low. Line plugged. Air supply is depleted. Defective pressure regulator. Line plugged. Flame is off. Incorrect H, or air flow. Incorrect sample pressure. Clean or replace line. Check filters and drier and dean or replace as necessary. Replace air cylinder. Replace regulator. Clean or replace line. Check filters and drier and dean or replace es necessary. Reignite end check pressure. Correct as necessary. Check pump, filter, and lines* Cleen end replace es necessary* Incorrect position of ignitor coil, Check position for proper location. (See Figure 2-3). Defective electrometer or power tupply card. A Zero improperly adjusted. Replace as necessary. Readjust correctly. Calibration improperly adjusted. Readjust correctly. If the trouble It traced to the fuse, a printed circuit card, a pressure regulator, the sample pump or the FID eek, refer to Removal and Replacement Procedure*. ELECTRONIC SYSTEM The electronic ryjtcrn consists of a 110 vdt power supply, an electrometer amplifier, and an auto ignitor containing a relay for Hj shutoff control. The system also includes a detector ceil temperature control and attenuator and range adjustments for calibration of the electrometer output. Optional electronics for creating a current output include 15 vdc power u 'oiy regulator, a f ilter and a voltage to current converter. The functional relationship of these com ponent is shown in the block diagram, Figure 2-2. Schematic diagrams are provided in Section 4. PRINCIPLE OF ELECTRICAL/ELECTRONIC OPERATION r: tjn-'''Tfnrpower switch is turned on, 115 vac is fed simultaneously to the rectifier circuit, the pump motor, the tnniv; liEML 0 fan motor, the igniror switch, the H, shutoff relay, and tha detector cell temperature control. The 110 vdc power supply card operates from a rectified source of approximately 540 vdc which is obtained by changing the 1 15 vac to dc. The output of the 110 vdc power suppiy card is a regulated 110 vdc which is fed to tha suppression adjustment control and the electrometer amplifier. The electrometer amplifier receives an additional input signal from the FID cell which determines the electrometer output voltage. The electrometer output is 0 to --100 vdc which it rhsn simultaneously fed to the range adjustment control (which In turn feeds the attenuator switch providing attenuation adjustment to the flame cell collector), the cutout meter, the voltage outputs and, when installed, the voltage to current converter. The electrometer output is reduced a: the output circuits for the 0 to 1 vdc and 0 to 10 mv outputs io the recorder. The 0 to --100 vdc input is transformed to 0 to --10 vdc for conversion to tha current output. i CAUTION When measuring voltages on pins at bottom of card!, use caution to prevent shorting pins together or to ground. Do not remove or replace cards or components with power on. A card extender is available from Bendix to aid in measuring voltages on cards. The card extender. Pert Number 55124S7, raises the card to a position where test points are more accessible, thus reducing the danger of ehorting contact*. Sensitive electronic component* can be destroyed by shorting of contacts. The use of elligetor type dips on card pins is not recommended. When a card is indicated to be defective, replace with e new card and recheck. NOTE When the con.erter is installed, the source power of 115 vac is transformed 'o 25 vac by transformer F-90X for the auto ignitor/H, shutoff card and the filter card. The 25 vac is a nominal voltage and the instrument operates satisfactorily ' when the voltage is anywhere between 16 and 30 volts. The input voltage is rectified as it enters tha filter card and the auto ignitor card. The filtered output of the filter card is then fed to the input of the 15 vdc power supply card and the converter card. Regulated 15 vdc from the power . * supply card is fed to the converter card for Ql, Q2, Q3 and Q4. Q5 receives power from the 16 to 30 vdc provided from the filter card. Before replacing a card, it is recommended that the card be rechecked to verify original findings. TESTING THE 110 VDC POWER SUPPLY CARO, Pert No.5511109 This card (located in socket J2) supplies + end --110 vdc for jet potential and suppression current. To determine if this card is functioning properly, refer to the master schematic and perform the following checks in the sequence indicated. ELECTRONIC TROUBLESHOOTING Electronic troubleshooting should be performed only by qualified technical personnel. The high voltages contained within the instrument may be barardous to anyone unfemihar with testing electronic equipment. When troubleshooting the electronics, a strip chart recorder with a nog* of 0 to 10 mvdc and a char; speed of 0.5 or 1 inch per minute and a multimeter of suitable range jj' required. Ui. ess otherwise specified, all dc voltages are referenced to 'ound. 1. Check from pin 1 to ground for+140 vdc tIO.v. If voltage is not present, remove the card and retest at the card socket. If voltage is still not present, a defective transformer or rectifier is indicated. If voltage is present, a defective 110 vdc card is indicated. 2. Check from pin 2 to ground for--140 vdc 10 v. If voltage is not present, remove the card and retest at tnB card socket. If voltage is still not present, defective transformer or rectifier is indicated. If voltage is present, a defective 110 vdc card is indicated. B.F.Goodrich Chemical Company Ayon Lake General Chemical Plant Avon Lake, Ohio STANDARD OPERATION PROCEDURE Century Organic Vapor Analyzer I,Scope This procedure is a method for the determination of vinyl chloride in air by the hydrogen flame ionization method. II. Discussion The vinyl chloride content of the building air shall be determined to comply with the company criteria for maximum concentrations and T.W.A. and to identify source leaks greater than the maximum allowable exposure of 50 ppm. The vinyl chloride content of poly evacuation blower exhausts, blend tank exhausts, dryer exhausts, and recovery vents shall be determined to comply with EPA regulations and plant efficiency standards. III. Safety 1. The Century OVA. is rated intrinsically safe but does not have Factory Mutual approval to date, therefore, the following precautions shall be taken in a Class I, Group D area. A. A Hot Work Permit will-be required. B. The instrument shall be On prior to entering the area. If a flameout occurs, the instrument shall be restarted outside the area. C. Only authorized personnel who have been fully trained and approved by both the general foreman and plant safety engineer shall operate the instrument. 2. Open flames and no smoking shall be observed during the hydrogen fill operation. Hydrogen gas, when mixed with air, is highly flammable. r e issued: January 9, 1974 Appendix II By: M. D. Rider gEMl u ij u c yu Century Organic Vapor Analyzer Issue 1 Page 2 of 13 1-9-74 3. Do not fill the hydrogen tank "beyond the maximum rater 'L:-'z-ss'-'e of 2j00 psi. The hydrogen tan^s used in the instrument are rr.de fre stainless steel, proof-tested to 6000 psi and 10j production tested to 46 jO psi. 4. Maintain the sample flow above 1-5 DIM to prevent a hydrogen rich ats.osp.here causing an explosion in the combustion chamber. The teflon c hamper vill not rupture. 5. Use only the fuses supplied with the instrument. Do not depress igniter button longer than 3 seconds. Wait 15 seconds between depressions to prevent fuse overload. The battery pack has two (2) power circuits, one for the pump motor and igniter and th*e other for the electronic circuits. Both circuits have resistive current limiting to restrict the short circuit current to an intrinsically safe level. In addition to the current limiting, there is a fuse (l amp. slo-blow and p- amp.) in each line to protect against overload conditions. 6. Do not operate the insthument without the hydrogen flow restricter, inlet and outlet ecintered stainless steel flame arrestors. IV. Battery Check Move Instr/Batt test switch to the Batt Test position and insure battery is charged by reading the Indication on the readout meter. V. Turn On Procedure1 2 3 4 1. The gas selector adjust should be preset to the desired dial Indication prior to turn-on. ALGC Unit No. 1 has a vinyl chloride set point of 460 for the 1-1COO ppm range. 2. Move the IN3TR switch to ON and allow one minute for warm-up. 3. Move CALIB switch to LOW and verify the meter reads 10 ppm. If not, adjust meter reading to 10 ppm with the CAU3 ADJ knob. Do not change the GAS SELECTOR ADJUST KNOB. 4. Move the pump switch tc ON and observe SAMPIE FLOW RATE indicator in a vertical position. A minimum flow of 1.5 LPM is required. Clean sample line filters (pickup prbbe filter and elbow filter) if less than 1*5 LPM. If necessary, clean sample-hydrogen mixer. Filters may be blown out with air or cleaned with alcohol and oven dried at 120F. Sonic cleaned is an acceptable method. NOTE: A millipore Aerosol Filter, M/.'-JP 037AO ,on the probe inlet will cut filter min r.emmce by vOr - A 3/l6 ' tube to l/8' Tx(nuil) reducer, SS-300-R-2, is required to attach filter. Ocrtury Organic Vapor Analyzer I#uo 1 Page 3 of 13 l-9-lk 5. Open Eg tank valve turn and observe the reading on the Hg tank pressure indicator. operation, 200 psi. Approximately 200 psi of pressure is needed for each hour of Refill IL, tank prior tc usir.g if tank pressure is less than .6. Open Hg supply valve 5 turn and observe that the reading on the 'S^ SUPPLY FEESSURE is 8 psi (or Hg factory set conditions). 7* Wait two minutes to obtain a hydrogen rich mixture and press IGNITER button. Do not depress for time periods longer than 5 seconds and wait 15 seconds between derre-.sions. Tnere will be a slight ''pop" as the hydrogen ignites and merer pointer will move upscale and return to a position upscale of zero. Immediately after ignition, release the IGNITER button. 8. After flame Ignition, alloy approximately one minute for the chamber to reach operating temperature. 9* Place cover on the instrument and check shoulder strap to make sure if properly snapped in position. 10. The instrument is now ready for use. VI. Operating Procedure* 2 * * 5 1.Obtain a Hot Work Permit from the building foreman. 2. Enter the survey area with the instrument ON and flame burning. 3- Hie probe may be used to measure VC1 concentrations inside a poly but do not enter the poly with the entire instrument. A 3/16" I-D. X 10 ft. polypropylene or teflon tubing may be used as an extension hose. The instrument does not have Class I, Croup D approval. L. Take employee exposure readings two feet from equipment hardware and five feet from floor level. The instrument may also be used as a leak detector by placing the probe flush to the equipment. 5. Headings taken on the Probe/Readout Assembly are linear from 1 to 1000 ppm (0.1^) on the ALGO unit when calibrated at25 ppm. For approximate concentrations in the 0.3 to lOjfc range when calibrated at 25 ppm, divide all readings by two. A calibration chart is required for each instrument in use. Each new unit placed into service should always have a full calibration over the entire range to determine the linearity of the Prcbe/Readout Assembly. See the section on calibration. C^rtcry Organic Vapor Analyzer Issue 1 Page k of 13 1-9-7^ 6. A portable battery powered Rustrak recorder (0-5 V. input) with shoulder straps may be used with the instrument in non-explosion proof areas. The Style "J" chart makes excellent copy for FPA records on blend tank exhaust at a chart speed of 0.5 Inch/minute. Align the instrument readout with the recorder reading by adjusting the recorder potentiometer behind the recorder face plate. 7* If a flameout occurs, return to a non hazardous area, ensure that the pump is running at an air flow rate greater than 1.5 LPM, then press the IGNITER button. VU. Shutdown Procedure1 2 3 4 5 6 * 8 1. Close TANK valve. Allow pressure to go to zero. 2. Close H SUPPLY valve. C . 3. Move INSTR switch to OFF. 4. Wait 5 seconds and move FUMP switch to OFF. 5. Plug AC battery charger into connector on battery cover. 6. Move the battery charger switch to the ON position.When fully charged, the pointer will be in line with "charged" marker above the scale. 7*When battery is fully charged, move the battery charger switch to OFF and disconnect from the battery connector. Approximately one hour of charging time is required for each hour of operation. However, an overnight charge is recommended since the charger can be left ON indefinitely without damaging the batteries. 8. To install a new battery pack, the instrument panel is removed from the case by unlocking the four (4) turn fasteners on the panel face and also removing the refill cap and elbow connector. The battery pack is removed by taking out the four (L) screws on-the..panel and disconnecting the power connector at the battery pack. Century Organic V&por Analyzer Issue 1 Page 5 of 13 I-9-7U VIII. Spot Check Calibration A weekly calibration creek is required using 25 ppm or 100 ppm of vinyl chloride in air compressed gas cylinder (or any monomer to be surveyed). This calibration will align the instrument readout with the previous prepared scale calibration graph. 1. Turn on instrument, air pump, hydrogen flow and ignite flame. 2. Allow the flame to bum for 10 minutes prior to calibrating. 3. Place a hydrogen two-stage regulator on the VC1 standard cylinder with a i inch O.D. tube on the regulator delivery fitting. Open the cylinder with a quick spurt to blew dust from the cylinder fitting prior to attaching regulator. Close the cylinder valve quickly. V. Slowly open the gas cylinder valve. 5. Turn the regulator knob until a low level of flow is audible from the flexible tubing. 6. Place sample pickup probe inside flexible tubing. Do not have a sealed system. 7. With the HIGH-LOW switch ir. the OFF potision, turn the CALIB ADJ knob until the needle on the probe readout assembly points to the exact concentration on the certified gas standard cylinder. 8. Turn the Hg TANX and H2 SUPPLY valves OFF. 9. Turn the PUMP switch to the OFF position. 10. With the INSTR switch in the ON position, unlock (counterclockwise) the GAS SELECTOR ADJUST knob and rotate until the needle on the probe readout assembly is on 10 PPM. 11. Lock, (clockwise) the GAS SELECTOR ADJUST knob and record the reading on the log sheet. To read the three digit number, read the single number in the "window" (e.g. M and then the two digit number on the "dial" (e.g. 76). In this example, the GAS SELECTOR ADJUST reading would be k'jS. 12. The instrument is ready for use in ambient vinyl chloride surveys (or other monomers when substituted). The above steps may be repeated using l.Ofvinyl chloride in air for blend tank exhaust surveys. Century Organic Vapor Analyzer T6sue 1 Page 6 of 1-9-71* 13 jy. Fun .Sr.~Ie Calibration Each instrument placed in service shculd immediately he checked for linearity or r.cn-linearity ana a rrarn prepared with the serial number of the instrument recorded on the graph. Iris graph shculd bo mode available to arose pecrle interpretin': the survey date. A copy cf the graph should be inside the instrument case at all times. All data reported on data sheets is considered raw data until correcteu by use of tnis graph. VC1 Standard, ppm A reading from this graph indicates that an OVA calibrated with a 50 FT VC1 standard may read 275 for ppm standard gas. There ere various ways to calibrate the OVA scale. Listed below are two methods using certified standards purchased from Precision Gas, New Jersey. A sample calculation for a gas dilution concentration using Method No. 2 is: 17.28 LPM AIH . 09 IPM 1. CJ*> vinyl chloride 17-37 LPM Total Volume ____ 51=1 .09 I-PV X .01 VC1 17-37 LPl-i Air x 106 PT ^1.8 Century Organic Vapor Analyzer ; Issue 1 Fege T of 13 1-9-74 2. Using certified vinyl chloride gas cylinders record the probe readout assembly readings for these approximate values 25, 100 and 500 ppta. 3* Draw graph using these three points on a 0-1000 ppm Beale. 4. Use a fourth standard, e.g. l.C$, and take a reading. If this reading is 2.C$, then the factor to be used for'all readings above a 1000 ppm is 0.5 In other words, divide all readings above 1000 ppn by two (2). 5* Record the instnnaent serial number, CIS SELECTOR ADJUST reading and the standard gas used on the graph. XT. Method T?o. 2 1. Follow steps l through 11 in the Spot Chech Calibration procedure above using 25 or ICO ppm vinyl chloride (or other monomer). 2. Calibrate precision laboratory rotameters (accuracy - 0.1 LPM) with air and nitrogen using the bubble tube or wet gas meter method. A Bendix Model 8851 Dynamic Flow Calibration unit may be used with or without a vinyl chloride permeation tube. 3* Connect ccmpre-ssed breathing air or charcoal filtered instrument air to the air rotameter and the 1.0$ certified vinyl chloride compressed cylinder to the nitrogen rotameter. The outlet flow is manifolded to give a blend of air and vinyl chloride. A restriction is placed in line to maintain a constant stable flow. XII. 4. Make various blends to allow two concentrations in 10-100 ppra range and two in 100-1000 ppm range. Trouble Shootir.r procedure Follow the guide provided by the attached Table 6-1, Trouble Shooting Procedure. Any problems associated with the hydrogen regulator system should be handled by shipping directly to this factory address. Century stems Corporation Box 133 Arkansas City, Kansas 67OO5 Phone: 316-44V-33II cr 3771 M. D. Rider shipping. U E. Spo ; cv of assistance in trouble shooting prior to i 1 } t century Orfianic Vapor Analyzer ' Issue 1 Page 8 of 13 1-9-71* ( XIIIf pgge^r.er.cied Spare Parts See attached sheet. XIV. leference and Service Q8A. Revision A. o. Center P.X. ^ * \ TROUBLE 6-1 Low sample flow rate on flow Indicator 6-Z - H 2 flame won't light TABLE 6-1 TROUBLE SHOOTING PROCEDURE *) Check particle filter in pickup assembly. b) Determine assembly containing restriction by process of elimination, i.e,, remove probe, remove readout assembly, remove elbow tubing connector and etc. c) If the restriction is in the side pack assembly, further isolate by disconnecting the sample flow tubing at various points, i.e,, pump output, chamber input, etc. Note: The Lnherent restrictions due to length of ample fine, flame arrestors, etc. , most be taken Into account when trouble shooting. REMEDY Replace or clean filter if clogged. Investigate the assembly containing the restriction to determine cause of blockage. Clean dt replace as required. If the restriction is found to be in the detector chamber, remove and clean or replace porous metal flame arrestors. If pump is found to be faulty, remove and clean or replace unit. a) Check sample flow rale [see 6-1 above). *>> Check glow plug by removing the chamber exhaust port and observing the glow when the IGNITE button le depressed. e) Check for rated H2 Supply Pressure. d) Check Hg flow rate by observing the PSI decrease In pressure on the Hg Tank Pressure gouge. The flow rate should be greater than 150 PSI decrease in pressure per hour. Note: Sufficient time (1 to 2 min. ) should be allowed for the H2 to flow through the capilUary to the detector chamber at initial turn-on/ If sample flow rate is low, follow procedure of 6-1 above. If glow plug does not light up, replace the plug. If low, adjust to proper level by turning' tho alien wrench adjustment on the regulator cap. The normal cause for flow restriction would he a blocked or partially blocked capillary tube. If flow rate is marginally low, attempt to compensate by increasing the H2 Supply Pleasure by one half or one PSI. Lf flow rate cannot be compen sated (or, replace capillary tubing. TROUBLE 6-2 (Continued 6-3 flame light* but won't stay lighted. 6 -1 1'lanie out alarm will not go on when Hj flame i, out. TABLE 6-1 (Continued) TROUBLE SHOOT LNG PROCEDURE e) Check to see if supply system is frozen up by taking unit into a warm area. f) Di*a*aemble the ffame chamber and check for contamination (*ee Figure 6-2). a) Follow procedure* 6-2 (a), (c), (d) and (f) above. REMEDY If there ie moi^furc in the supply B/Btcm and the unit must be operated in sub-freezing tcmprerature purge the Hg system with dry Nj and ensure the gao used is dry. If the chamber ia dirty, clean with ethyt alcohol and bake dry. If fuel jet is misaligned, ensure the porous metal flame arrestor is properly tested. a) Check instrument calibration setting, * b) U procedure (a) doe* not resolve the problem, the probable cauie i* a malfunction in the preamp asiembly. The probable cause of the output signal not going low enough to trigger the flame out alarm is current leakage to the collecting electrode due to contamination or moisture in the chamber or electronics housing, Dry chamber out by running unit or purging with dry or disassemble and clean (see Figure 6-2), If moisture is In the electronics housing replace desicant container (see 6.2. 5) Return electronics assy to factory for repair. GtNC TROUBLE 6-5 Slow response time, i. e., time to obtain response after gas is applied to input. TABLE 6-1 (Continued) TROUBLE SHOOTING PROCEDURE a) Check to ensure that Probe is firmly seated on the rubber seal in the Readout Assembly b) Check sample flow rate per procedure 6- 1 above. c) Investigate whether sample input system is leaking by closing off input at the probe and observing the flow rate and sound of the pump. Another method is to blow smoke around the various connections and observe the instrument response. REMEDY Reseat by holding the probe firmly a garni t the rubber scat and then lock in position with the knurled locking njt. See 6-1 above. Through the process of elimination, find the source of the leak and repair. 6i `"1; w recovery time, i.e., too long !4 time for the reading to get back to ambient after exposure to a high level organic vapor. .Ambient background read in clean environment is too high a) This problem is normally caused by contamination In the sample input line which absorbs the organic vapor and then has to be pumped for a long period to get the system clean of vapors again. Charcoal in the lints would be the worst type of contamination. Isolate through the process of elimination where the contamination is (see f-l [b}) b) Check flame chamber for contamination. a) An ambient background reading can be caused by hydrocarbon* in the fuel or fuel supply system. Place finger over sample probe tube restricting sample flow and if mcler indication does not go down significantly the contamination 13 probably in the Hg fuel. Clean or replace contaminated sample line or assembly as required. Clean as required. Use a higher grade of hydrocarbon-free hydrogen. Check for contaminated fittings on fitlinfl hos e as i emb' y . TROUBLE 6-7 (Continued) 6-8 Pump will not run 6-9 No power to electronics but pump runs* 10 Ho power to pump or electronic* TABLE 6-1 (Continued) TROUBLE SHOOTING PROCEDURE REMEDY b) An ambient background reading can also be caused by hydrocarbon contamination in the sample input system. The most likely cause would be a coataminent absorbed or condensed in the sample tine. Clean and/or replace the tample input lines- Normally the tinea will clear up with sufficient running. c) It should be pointed out that running the instrument tend* to keep down the buildup of background vapor*. There fore, run the unit whenever possible and store it with the carrying case open in clean air. a) Check l AMP slow blow fuse on battery pack cover. Replace fuie. Tf fuec continue* to blow when igniter awltch i* cloeed check ignitor for abort circuit. H igniter ia not the problem there ia a *hort in the wiring or pump motor. a) Check 1/4 AMP fuse on top of battery pack. Replace fuse. It fuse continue* to blow there is a short in the electronics assembly. a) Place battery on charger and see if power if then available. If power io available battery pack i* dead or open. iI i Pg. 13 of 13 CENTURY SYSTEMS CORPORATION 1 t.O. OX 151 AMALIA* CITY, XANSAi 47O0J ,,mtfNOMC 1U 447.55:i 4X7.5371 1 : Part No. 510027-1 510030-2 510C35-2 510040-2 510045-1 510 052 -1 ^0055-1 510060-2 510063-1 510070-1 510073-1 510075-2 510080-1 510085-1 510090-1 510094-1 510100-1 510100-2 510113-1 510116-1 510125-1 01 0126-1 PRICE LIST FOR OVA-98 SPARES 520000-1 Effective Date - Dec. 1, Description Price Igniter Readout Assembly Probe Assembly Funnel Sampler Assembly A.C. Battery Charger Assembly Shield (Switchguard) Cylinder Assembly Pump Assembly Pump Diaphragm Battery Pack Assembly Capillary Tube Assembly Flow Indicator Assembly Case Assembly (Side Pack) Hydrogen Filling Assembly Instrument Carrying Case Assembly Carrying Strap Assembly (Shoulder Strap) K. F. Regulator Assembly L. P. Regulator Assembly Motor Assembly (Mod) Replaceable Porous Metal Filters Close Area Sampler Assembly Tubular Sampler Assembly $ 2. 00 105. 00 25. 00 6. 50 95. 00 . 95 135.00 39.40 2. 00 75. 00 7. 50 19. 50 30. 00 60. 00 60. 00 9.75 35. 00 35. 00 70. 00 5. 00 4. 75 4. 75 SENC OOfi? PRICE LIST FOR OVA-93 SPARES ''Cont'd. ) Part No. 510250-1 510250-2 510254-1 510301 -1 510319-2 ^0251 -2 250S MDL- 1 ACC-1/4 1/4 Amp Desc r iotion Mixer/Burner Assembly Mixer/Burner Assembly (Rebuilt with exchange) Mixer/Burner Assembly (with stainless steel filters) Handle Assembly Eccentric Assembly Exhaust Port Assembly (with stainless steel flame arrestor) Elbow Connector Assembly Meter Movement Slo-Blo fuse, 1 amp. Standard fuse Eittlefuse Micxofuse Teflon Tubing # Page - 2 - Price $ 23. 10 8. 10 23. 10 8. 50 7. 95 5. 00 4. 95 35. 00 . 40 . 15 1.25 1. 00 Prices, are f. o. b. Arkansas City, Kansas, and are subject to change without notice. Shipping will be by Parcel Post or United Parcel Service unless otherwise instructed. Prices are valid for use in continental U.S.A. only.