Woodstove Manufacturer

Presentation to the Office 

Management and Budget

September 25, 2013
Today’s Topics

• Cost effectiveness of proposed 

standards – NERA Presentation

• Why lower standards are a “num

game” that will retard reductionwoodstove PM.

• NTTAA Test Method Concerns• What can we do?
• Lower standards ( e.g., 2.5 g/h or 1.3 g/

based on current, dimensional lumber ctesting is a “numbers game,” that creatan illusion of progress.
Test Fuel

EPA Method 28 D. fir Dimensional Lumber Test Fuel Crib

Note: The bars represent the interior side walls of the stove.
• Performance scores based on crib fuel t

do not correlate with performance in hwith “real” fuel (cordwood). – State air quality regulators have long comp

about this problem. – A study by Dr. James Houck1 comparing “f

performance data with certification (lab) ddemonstrates that it is a real problem.

1A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with Certification Emission Values and A Comparison between In-Home Uncertified and Certified Wood Stove Emissions, Dr. James Houck, February 2012
Houck Study - Major Conclus

• There is no correlation between certific

values and the real world emission rate

• And further, rank orders change. 

– A stove with a higher certification value m

perform better in the field than one with a certification value.
Mean Emission Rate and EPA Certification Values by Coded Sto

There is no correlation between certification values and the in-situ emission rates.

Source: A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with U.S. EPA CerValues and A Comparison between In-Home Uncertified and Certified Wood Stove Particulate Emissions, Dr. James Houck, Fe
Mean Emission Rate and EPA Certification Values by Coded Sto

There is no correlation between certification values and the in-situ emission rates.And further, rank orders change. A stove with a lower certification value may not perform as well in the field as one with a higher certification value.

Source: A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with U.S. EPA CerValues and A Comparison between In-Home Uncertified and Certified Wood Stove Particulate Emissions, Dr. James Houck, Fe
• However, certified stoves do perfor

significantly better than conventionstoves (>50% PM reduction).
Mean PM Emission Rates for Uncertified Stoves and for Certified S

Grouped by Low, Medium, and High EPA Certification Categori

Source: A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with U.S. EPA CerValues and A Comparison between In-Home Uncertified and Certified Wood Stove Particulate Emissions, Dr. James Houck, Fe

The EPA certification values do not predict the relative ranking of the stoves under real-world use.To smooth some of the inherent data variability, stove models were grouped by Low, Medium and High certification categories.
Mean PM Emission Rates for Uncertified Stoves and for Certified S

Grouped by Low, Medium, and High EPA Certification Categori

Source: A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with U.S. EPA CerValues and A Comparison between In-Home Uncertified and Certified Wood Stove Particulate Emissions, Dr. James Houck, Fe

The EPA certification values do not predict the relative ranking of the stoves under real-world use.
Certified stoves do have substantially lower particulate emissions under real-world operating conditions.

Mean PM Emission Rates for Uncertified Stoves and for Certified S

Grouped by Low, Medium, and High EPA Certification Categori

Source: A Comparison of Particulate Emission Rates from the In-Home Use of Certified Wood Stove Models with U.S. EPA CerValues and A Comparison between In-Home Uncertified and Certified Wood Stove Particulate Emissions, Dr. James Houck, Fe

53% Reduction
Test Method Precision

• The precision of the crib wood test met

will not allow us to reliably distinguish performance differences in the range ointerest. 

– Curkeet /Ferguson Precision Study

• Study used EPA Accredited Laboratory Proficie

Round-Robin Test Program Database

• Study was conducted in accordance with ASTM 

which is the consensus standardized method fdetermining test method precision.
Conclusions from Precision Analy

the EPA Laboratory Proficiency D

• The “within the same lab” precision of t

weighted average emissions at the 95% confidence level is at best ±2.9 grams pand typically about ±3.5 to ±5.4 grams phour. 

• The “between labs” precision, at the 95

confidence level is ±4.5 to ±6.4 grams phour. 

Source: “EPA Wood Heater Test Method Variability Study - Analysis of Uncertainty, RepeataReproducibility based on the EPA Accredited Laboratory Proficiency Test Database”, R. Curke

Ferguson. Submitted to EPA on October 6, 2011. The report is available upon request. Thalso summarized in Hearth and Home Magazine, March 2011 Issue.
• Variability in wood heater emissio

testing results for any given appliis most likely a function of the rannature of burning wood, no matt

how tightly you try to control the process. 

• Tightening test parameters (e.g., test fue

moisture range) would simply increase cowould not significantly improve precision would further widen the gap between latesting and real world operation.
• Although it has been shown that EPA certified stoves as a 

perform substantially better in the field than conventiona(uncontrolled) models, there is no predictable relationshilaboratory test results using dimensional lumber cribs anworld performance for any given model.

– Rank orders can change.

• The test methods used to determine emission performan

somewhat blunt instrument – not capable of distinguishinperformance differences in the range of interest.

• The random variability associated with burning wood is th

factor in the poor test method precision.

• NERA has shown that even if the emission reductions fro

the emission limits were real and achievable in the field, tlimits are not cost effective and have negative impacts on 

to increased prices.
• Increases in consumer retail price and t

likely decrease in the number of modelavailable in the market will slow progrechanging out the 6 million uncontrolled still in American homes.
2010 National Particulate Emission

Freestanding Stove Category

Certified NonCat: 15,188 

Tons, 10%

Certified Cat: 

5,016 Tons, 3%

All Pellet: 1,445 

Tons, 1%

Conventional 

135,420 Tons, 

86%

6 MStovTota

~3.3 MillionStoves – 14% of Total PM Total PM 

2010: 1

Source: The Fraction of Freestanding Wood-Fueled Stoves in Current Use That are U.S. Certified Cordwood Stoves and Wood Pellet Stoves, Dr. James Houck, July 2011
National Technology Transfer a

Advancement Act (NTTAA)

• EPA must adopt ASTM consensus-based test methods for 

woodstoves, because it cannot find that it would be “illeg

“impractical” to do so under NTTAA.

– ASTM test methods (which EPA participated in creating)

• ASTM E2515 - measuring particulate in smoke • ASTM E2780 – fueling and operation during testing and data ave

determine performance rankings (“compliance algorithm”).

• EPA plans to adopt the ASTM particulate measurement m

plans to “Christmas Tree” the operating method in unsupways:

– With an EPA substitute for the “low burn rate” criteria, whi

adopted to improve the real world performance of certifie

– With an EPA substitute for the compliance algorithm for St

standards, which has not been demonstrated to be achieva
• The path forward here is clear: – EPA needs to adopt innovative approaches that w

“bridge” to a different paradigm: 

• A program based on a cordwood test method that will 

new generation of certified woodstoves with laboratorperformance profiles that are better related to “real wo

operating conditions. – Manufacturers are willing to work with EPA and o

stakeholders to develop such a program.

• An ASTM Task Group is hard at work creating a 

cordwood test method. – EPA and a number of state agencies are participa

manufacturers and test laboratories in this effort, hopefully can be brought to a conclusion early in 

What can be done?
• Questions?

• Thank you!