United States Environmental Protection Agency Air and Energy Engineering Research Laboratory Research Triangle Park NC 27711 Research and Development EPA/600/S7-89/002 July 1989 Project Summary Woodstove Emission Sampling Methods Comparability Analysis and In-Situ Evaluation of New Technology Woodstoves Carl A. Simons, Paul D. Christiansen, James E. Houck, and Lyle C. Pritchett This project compared the simul- taneous results from three wood- stove sampling methods and evalua- ted the particulate emission rates of conventional and Oregon-certified catalytic and noncatalytic wood- stoves in six Portland, OR, houses. EPA Methods 5G and 5H and the field emission sampler (Automated Wood- stove Emission Sampler — AWES) were compared in the laboratory un- der simulated field conditions. The first comparability test used a con- ventional woodstove on a Portland burn cycle. The second and third tests used a certified catalytic wood- stove on Portland and northeastern U.S. burn cycles, respectively. EPA Method 5G and the AWES were also compared on a catalytic stove in one house. Field sampling was conducted on conventional and Oregon-certified low emission noncatalytic and cata- lytic woodstoves in two houses each. Results showed that the AWES system was within an absolute differ- ence range of 0.7 to 2.5 g/hr of Meth- ods 5G and 5H. Field tests showed that certified stoves can achieve sig- nificant reductions in particulate emissions. All of the field data ex- ceeded certification emission rates by at least 25%. Several components of one catalytic woodstove failed (by- pass damper gasket missing and damper not closing, plugged catalyst, leaky ash cleanout door), resulting in emissions more than twice the 20 g/hr conventional woodstove average. This Project Summary was devel- oped by EPA's Air and Energy Engineering Research Laboratory, Re- search Triangle Park, NC, to announce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction Regulation of woodstove emissions in Oregon and Colorado, in addition to recent regulatory actions by the U.S. Environmental Protection Agency to control woodstove particulate emissions on a national level, has stimulated devel- opment of many low emission woodstove models as determined by laboratory certification procedures. These regula- tions have also resulted in the develop- ment of several regulatory-agency- approved or "reference" woodstove particulate emission sampling methods. In addition, OMNI Environmental Ser- vices, Inc. has developed an in-situ woodstove emission sampling system called the Automated Woodstove Emis- sion Sampler (AWES)/Data LOG'r. This Project had two primary objec- tives: 1. A comparability analysis of three woodstove particulate emission sam- pling methods. The sampling meth- ods compared included the EPA ------- Table 1. The particuiate emission data for the six woodstove models evaluated are: Mean Particulate Emission Woodstove Model Rate(glhr) Range (g/hr) Conventional Technology 1 Conventional Technology 2 Low Emission Non catalytic 1 Low Emission Non catalytic 2 Integral Catalytic 1 Integral Catalytic 2 25.5 13.8 8.3 18.6 4.0 43.3 20.9 9.5 6.7 13.3 2.7 31.2 -29.4 -22.3 - 10.9 •24.1 - 4.7 -61.9 Method 5H (equivalent to Oregon Method 7), the EPA Method 5G, and the OMNI Automated Woodstove Emission Sampler (AWES)/Data LOG'r. The sampling system compar- ability analysis included three labora- tory tests using all three sampling methods, and one in-situ test using only the Method 5G and the AWES/Data LOG'r systems. 2. An evaluation of the in-situ per- formance of three woodstove technol- ogy classifications: conventional tech- nology, low emission noncatalytic, and integral catalytic woodstoves. The in-situ evaluations were conduct- ed in six houses in Portland, OR. Two models of each of the three wood- stove technology classifications were evaluated. Previous in-situ studies indicated that the new woodstove technologies (low emission non-catalytic and integral cata- lytic woodstoves) do have the potential for reduced particulate emissions as compared to conventional technology woodstoves. Design features generally associated with new technology non catalytic woodstoves are: relatively small firebox (i.e., <57 L or 2.0 ft3); firebox usually insulated with firebrick and/or mineral wool; stove designed to burn only wood; no underfire air; and a secondary air supply. Data from pervious in-situ studies raised questions reguarding the generally wide range and higher in-situ particulate emission rates observed for the wood- stoves as compared to laboratory certifi- cation emission values. Significant factors influencing woodstove performance un- der laboratory and in-situ emission test- ing conditions include differences in burn rates, fuel loading patterns, fuel moisture content, fuel species, sampling methods, and operator experience. Therefore, this study was designed to evaluate whether differences in woodstove emission per- formance, as determined by laboratory certification versus in-situ sampling pro- cedures, was an artifact of differences in the sampling methods or other factors. Sampling Method Comparability Three sampling method comparability tests were designed to compare the per- formance of OMNI's AWES/Data LOG'r emission sampling system against EPA reference woodstove sampling Methods 5G and 5H. Each laboratory test took 7 consecutive days, duplicating the standard AWES in- situ sampling duration protocol. The first laboratory test was conducted on a conventional technology woodstove and used burn rates, fuel species, and fuel loading patterns representative of the greater Portland, OR, metropolitan area (Test L01). The second laboratory test, conducted on an Oregon Department of Environmental Quality certified integral catalytic woodstove, also used fueling representative of Portland (Test L02). The third laboratory test was conducted on the same certified integral catalytic wood- stove and was fueled using burn rates, fuel species, and fuel loading patterns representative of the northeastern U.S. (Test LOS). Split cordwood was the fuel in each test. Douglas fir was used for tests L01 and L02, and a mixture of 50% red oak and 50% sugar maple purchased in Hudson Falls, NY, was used for test L03. Assuming a ±20% accuracy associat- ed with Methods 5G and 5H, the AWES/Data LOG'r system calculated emission rates are in the estimated emis- sion rate range of Methods 5G and 5H. A comparison of the measured emiss rates (Method 5G with 5H adjustm factor, Method 5H - proportional sam rate) for all laboratory tests shows t the AWES system (intermittent sampl cycle) was within a range of 0.7 to g/hr of the EPA woodstove referer sampling methods. New Technology Woodstove Emission Comparability The in-situ evaluation of the p formance of three woodstove tei nologies was conducted in six houses Portland, OR, with the AWES/Data LO sampling system from January 15-Ma 27, 1987. In addition, a comparability 1 of the Method 5G and the AWES/D LOG'r sampling systems was conduc for 1 week in one of the six houses 1 used a certified integral catalytic wo stove. The woodstove technologies evalua included two conventional technok woodstoves, two low emission none! lytic woodstoves, and two integral c< lytic woodstoves. Five 1-week samp periods were completed in each sti house. The AWES/Data LOG'r system; each house were programmed to sam intermittently (1 minute on, 29 mini off) during each sampling week. AV\ units with probes located 30.5 cm ab the woodstove's flue collar were used the conventional technology and emission non catalytic woodstoves. 1 additional AWES samplers were usec sample 30.5 cm above the woodstov flue collar and before the catalyst for integral catalytic woodstoves. Creosote samples were also collec from the six study houses. The chim of each house was swept at the start the midpoint, and at the end of the stu ------- Conclusions Several conclusions arise from the data from the in-situ performance portion of this study: • The new technology woodstoves (low emission non catalytic woodstoves and integral catalytic woodstoves) can significantly reduce particulate emissions and creosote deposition rates when properly operated and matched to chimney systems meet- ing manufacturer's specifications. • Several components of integral catalytic woodstove 1C 2 failed (by- pass damper gasket missing, bypass door not closing completely, catalyst plugging, air leakage through the ash clean out pan), resulting in relatively poor particulate emission perform- ance. In addition, there may have been problems with operator use and maintenance of the woodstove, since the homeowner did not seem to be aware of periodic maintenance procedures even though this infor- mation was provided at the begin- ning of the study. Since these failures were observed within 4 months after the installation of the woodstove, questions are raised re- garding the durability of this stove's emission control system. However, since these observations are based on one stove, it is difficult • Considering the accuracies associa- ted with the AWES and Method 5G sampling methods, the calculated particulate emission rates are statis- tically identical. However, the AWES emission rates indicate a high bias relative to Method 5G, as also de- monstrated in the laboratory sam- pling methods comparability test. • Calculated flue gas volume mea- sured by the AWES system was within 2% of the mean flue gas volume determined by the "Stack 02 Gas Analyzer," "CO Ratio," and "Stack CO2 and CO Gas Analyzer" combustion calculation methods. • The precision and accuracy of the AWES/Data LOG'r sampling system are demonstrated by a comparison of particulate emission rates in the in-situ comparability test and labor- atory comparability test L02. Each of the two tests used the same wood- stove model, the same fuel species, and a low to moderate burn rate • Creosote deposition rates generally followed emission rate performance by stove technology. However, cau- tion must be used in the inter- pretation of this data due to the complexities of creosote deposition and removal mechanisms ------- Carl A. Simons, Paul D. Christiansen, James E. Houck, and Lyle C. Pritchett are with OMNI Environmental Services, Inc., Beaverton, OR 97005. Robert C. McCrillis is the EPA Project Officer (see below). The complete report, entitled "Woodstove Emission Sampling Methods Comparability Analysis and In-Situ Evaluation of New Technology Woodstoves," (Order No. DE 89-001 551/LP; Cost $21.95, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Air and Energy Engineering Research Laboratory U.S. Environmental Protection Agency Research Triangle Park, NC 27711 //- "^^\ t.'.G.- United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 . , ^NALTY T OlPOSJAGf crp , *,„* iKH? J ,;t' } 3 ,}j l(-oi.,.^- / )( wn IFRtv'ATE /fse ,-3oo; ^ * * i 02 Official Business Penalty for Private Use $300 EPA/600/S7-89/002 AGE"CT ------- |