EPA 340/lDecemberVisible EmissionsEPA MethodsPreparedField Manual9 and 22by:EasternTechnical AssociatesPO Box 58495Raleigh, NC 27658andEntrophyResearchEnvironmentalist,Inc.PO Box 12291Triangle Park, NC 27709.’!/-r-F ;. VP.’6 . ,’*ContractNo. 68-02-4462Work AssignmentNo. 91-188EPA Work AssignmentManagers:Karen RandolphEl? Project Officer: Aaron Martin/and Kirk FosterIUS. ENVIRONMENTALPROTECTIONAGENCYStationarySource ComplianceDivisionOffice of Air Quality Planning and StandardsWashington,DC 20460December1993-92-0041993

ContentsIntroduction. 2. .““.”.3A Brief History of Opacity . .“.“.“.H.”.“.“.”.””Opacity Measurement Principles .“.“.“.”.“.”. 4Records Review . . . . . . . . . . . . . . . . . . . .“.“.”.8Equipment . . . . . .“.”.9Field Operations . . . . . . . . . . . . .“. 11Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . .*. 14Data Review . . . . . . . . . .“.““.Appendix A: FormsAppendix B: Method 9Appendix C: Method 2215

JntroductionThe Federal opacity standards for various industries arefound in 4OCPR Part 60 (Standards of Performance forNew and Modified Stationary Sources) and 40 CFR Part61 and 62 (Emission Standards for Hazardous Air Pollutants). These standards require the use of ReferenceMethod 9 or Reference Method 22, contained in Appendix A of Part 60, for the determination of the level orfrequency of visible emissions by trained observers.In addition to the plume observation procedures, Method9 also contains data reduction and reporting proceduresas well as procedures and specifications for training andcertifying qualified visible emission (VIZ) observers.State Implementation Plans (SIPS) also typically includeseveral types of opacity regulations, which in some casesmay differ from the federal opacity standards in terms ofthe opacity limits, the measurement method or test procedure, or the data evaluation technique. For example,some SIP opacity rules limit visible emissions to a specified number of minutes per hour or other time period(time exemption); some limit opacity to a certain levelaveraged over a specified number of minutes (time averaged): some set opacity limits where no single readingcan exceed the standard (instantanous or “‘cap”). Regardless of the exact format of the SIP opacity regulations. nearly all use the procedures in Method 9 forconducting VE field observations and for training andcenifying VE observers. The observation procedums contain instructions on how to read the plume and recordthe values, including where to stand to observe the plumeand what information must be gathered to support thevisible emission determinations. Thi validity of the VIIdeterminations used for compliance or noncompliancedemonstration purposes depends to a great extent on howwell the field observations are documented on the VEObservation Form. This field manual will stress the typeand extent of documentation needed to satisfy Method 9requirements.Federal opacity standards and most SIP opacity regulations are independently enforceable, i.e., a source may becited for an opacity violation even when it is in compliance with the particulate mass standard Thus, visibleemission observations by qualified agency observers serveas a primary compliance surveillance tool for enforcement of emission control standards. In addition, manyfederal and SIP regulations and construction and operating permits also require owners/operators of affected facilities to assessand report opacity data during the initialcompliance tests and at specified intervals over the longterm.Regulated sources may be subject to stiff penalties forfailure to comply with federal and state emission standards, including opacity standards. Civil and administrative penalties of up to 25,000 per day per violationcan be assessedunder the Clean Air Act (CM). Statesand local agencies are encouraged under Title V of theCM to have program authority to levy fines up to 10,000per day per violation. Therefore, visible emission determinations for compliance demonstration or enforcementpurposes must be made accurately and must be sufficiently well documented to withstand rigorous examination in potential enforcement proceedings, admiitrativeor legal hearings, or eventual court litigation.Produderrors or omissions on the visible emissionevaluation forms or data sheets can invalidate the data orotherwise provide a basis for questioning the evaluation.only by carefully following the procedures set forth inMethod 9 (or any other reference method) and by payingclose attention to proper completion of the m Observation Form can you be assured of acceptanceof the evaluation data.The purpose of this simplified manual is to present astepby-step field guide for inexperienced VE observerswho have recently completed the VIZ training and certification tests on how to conduct VE observations in accordance with the published opacity methods. The basicsteps of a well-planned and properly performed VE inspection are i.Uust.tatedin the inspection flow chart (seeFigure 1). This manual is organized to follow the inspection flow chart Sections of the reference methods thatmust be carefully observed or followed during the inspection are highlighted. Method 9 and Method 22 arereprinted in full in Appendix B and Appendix C respectively. A recommended field VE Observation Form, ineluded in Appendix A, may be copied or modified forfield use.It should be noted that much of the information presented in this simplified field manual has been derivedf&m a number of previously published technical guides,manuals. and reports on Method 9 and related opacity.

U.S. Bureau of Mines in the early 1900s in their effortsto improve coal combustion practices. It has beeu usedextensively ever since by industry and control agencies toassessand control emissions.FUEL/AIR MIXTURE RATIO. EXCESS AIREXCESS FUELOPTIMUMHEAT LOSS&g&m NIN FLUE GASD(CESSOXYGENFigure1. VE inspectionOP71hl;Mw ENEXCESSOPACITYFlow Chart4RingelmannOf OpacityEarly HistoryThe first smoke evaluation system evolved from a concept developed by MaximilIian Ringelmann in the late18Oqs. Ringehnann realized that black smoke from coalfired boilers was the result of poor combustion efficiency.Darker smoke meant poorer efficiency, and to measurethe darkness of the smoke, Ringelmann devised a chartwith four different black grids on a white background. Ata. distance of at least 50 feet, the grids on the chartappear as shades of gray. By matching the shade of asmoke plume with the apparent shade of a grid on thechart, Ringelmann was able to classify emissions. Withthis information, he could adjust the fuel-to-air ratio of afurnace to increase efficiency and decrease the smoke.The Ringelmann Chart was adopted and promoted by the3Ringelmammethods. For more detailed information on Method 9and the application of Method 9, please consult the listof publications at the end of this manual.A Brief HistoryINCOMPLETECOMBUSTION2Chart1PeriodBy 1910. many larger municipalities had adopted theRingelmann Chart into their health and safety reguIations in an attempt to control smoke as a nuisance. Toprove a violation of a nuisance code, it was necessary toprove that:llThe smoke was denseThe smoke was a nuisauceBetween 1914 and the 1940s. the courts recognized thatsmoke could be regulated under the police power of thestate, and a regulatory agency no longer had to provethat the smoke was a nuisance. The U.S. Surgeon General declared that smoke and other air pollutants werenot only a nuisance but a health hazard in 1948 after aseries of air-pollution-related deaths in Donora, Pennsylvania This set the stage for federal regulations and thecontrol of air pollution to protect the public health.3

.Equivalent’OpacityIn the 1950s and 1960s Los Angeles added two majorrefinements to the use of visible emissions as a tool forcontrolling particulate emissions. The Ringelmann methodwas expanded to white and other colors of smoke by theintroduction of “equivalent opacity.” Equivalent opacitymeant that the white smoke was equivalent to aRingelmann number in its ability to obscure the view ofa background. In some states, equivalent opacity is stillmeasured in Ringelmann numbers, whereas in others theO-to 100 percent scale is used. Also, by training and certifying inspectors using a smoke generator equipped withan opacity meter, regulatory agencies ensured that certified inspectors did not have to carry and use Ringelmanncards.In 1968, the Federal Air Pollution Control Office published AP-30. Optical properties and Visual Effects ofSmoke-Stack Plumes, describing the accuracy of a smokereader’s observations compared to a tmnsmissometer. AP30 also discussed the effect on opacity observations whena plume is viewed with the sun in the wrong place relative to the source.Method 9The Environmental Protection Agency (EPA) stopped using Ringelmann numbers in the New Source performanceStandards when the revised EPA Method 9 was promulgated in 1974. All NSPS visible emission limits arestated in percent opacity units. Although some stateregulations (notably California’s) still specify the use ofthe Ringelmann system for black and gray plumes, thenational trend is to read all emissions in percent opacity.EPA conducted extensive field studies on the accmacyand reliability of the Method 9 opacity evaluation technique when the method was revised and repromulgatedin response to industry challenges concerning certainNSPS opacity standards and methods. The studies showedthat visible emissions can be assessedaccurately by properly trained and certXed observers. Two central featuresof Method 9 involve taking opacity readings of plumes atWsecond intervals and averaging 24 consecutive readings (6 minutes) unless some other time period is specified in the emission standard (some NSPS specify a3-minute averaging period).and hazardous waste incinerators. Visible emissions standa& are also applied extensively in controlling fugitiveemissions ‘km both industrial processes and non-process dust sources such as roads and bulk materials storage and handling areas. Often there are no convenientaccurate stack te’sting methods for measurement of emissions from unconfined sources other than opacity methods.Method 22Since EPA promulgated Method 22 in 1982, it has become an important tool in the conaol of visible emissions. Method 22 is a qualitative technique that checksonly the presence or absence of visible emissions. Method22 or a similar method is often used in the regulation offugitive emissions of toxic mater&. Unlike with Method9, Method 22 users don’t have to be certified. However,a knowledge of observation techniques is essential forcorrect use of the method. Therefore, Method 22 requires the observer to e trained by attending the lectureand field practice session of the Method 9 smoke school.Opacity MeasurementPrinciplesThe relationships between light transmittance, plumeopacity, and Ringelmann numbers are presented in Table1.Table1.Comparisonof RingelmannNumber,PlumeOpacity, and Light TransmittancePlume opacity emission standards and requirements rethe mainstayof federal, state, and local enforcement efforts. Today, more visible emission observers arecertified annually than at any time in the past. Thiscertification rate will continue to increase with the increase of federal and state regulations on industrial processesand combustion sources such as municipal, medical,mainA literal definition of plume opacity is the degree towhich the transmission of light is reduced or the degreeto which the visibility of a background as viewed throughthe diameter of a plume is reduced. In simpler terms,opacity is the obscuring power of the plume, expressed in

percent. In physical terms, opacity is dependent upontransmittance (I/I) through the plume, where IO is theincident light flux and I is the light flux leaving theplume along the same light path. Percent opacity can becalculated using the following equation:and creating a high .bii (positive error) in opacity readings. On the other hand, when the sun is properlyoriented in relation to the plume and the plume color isidentical with the background color, observers will generally have diffculty distinguishing between the plumeand the background.Percent opacity (l-U(I) x 100.Variables InfluencingObservationsOpacityMethod 9 advises:The appearanceof a plume as viewed by an observerdepends upon a number of variables, some of whichmight be controllable and some of which might notbe controllable in the fieldThe factors that influence plume opacity readings include particle density, particle refractive index, particle size distribution,particle color, plumebackground, pathlength, distance and relative elevation to stack exit, sun angle, and lighting conditions.Particle size is particularly significant; particles decreaselight transmission by both scattering and direct absorption. Particles with diameters approximately equal to thewavelength of visible light (0.4 to 0.7 pm) have the greatest scattering effect and cause the highest opacity. For agiven mass emission rate, smaller particles will cause ahigher opacity effect than larger particles. You shouldnote that particl