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
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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
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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
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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
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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Penalty for Private Use $300
EPA/600/S7-89/002
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