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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