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MASONRY HEATER NSPS PROPOSAL FINAL DRAFT 

PREPARED FOR: 

THE HEARTH, PATIO & BARBECUE ASSOCIATION 

Masonry Heater Caucus 

PREPARED BY: 

Robert Ferguson 

& 

David Menotti 

September 24, 2012 

 
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Background 

In February, 2008, the Hearth Patio & Barbecue Association (HPBA) Masonry Heater Caucus 

submitted a White Paper1 to EPA reporting on the emission performance of masonry heaters. 

This paper included background information about masonry heaters, test data accumulated from 

two decades of testing, conclusions drawn from that data and recommendations to EPA about 

how to best integrate masonry heaters into the clean-burning solid fuel heating options that might 

be considered in particulate matter (PM) impacted air sheds. 

The White Paper stated: 

Modern masonry heater designs originated in Europe and those designs have been in use for 

many decades, if not centuries. While masonry heaters are installed in relatively large numbers 

across Europe, they represent only a small niche in the solid-fuel burning market in the United 

States. Masonry heaters are site-built, often by individual masons, making it hard to provide a 

precise number of installed units. The [HPBA] Masonry Heater Caucus estimates that between 

600 and 1,000 masonry heaters are installed in North America each year. This represents only a 

fractional percentage of all solid-fuel burning appliance sales and installations. 

More recent market research conducted by a masonry heater producer in conjunction with the 

Small Business Regulatory Enforcement Fairness Act (SBREFA) review conducted by OMB, 

SBA and EPA in the summer of 2010 identified approximately 250 U.S. businesses involved in 

the manufacturing, sales, and/or installation of masonry heaters. All identified masonry heater 

industry participants qualify as small businesses. 

The largest manufacturers of units are foreign entities (Finland, Canada, Germany and “others” 

by order of sales). Their products are not custom site-built heaters but are instead site-assembled 

and easily account for the majority of all sales. All of these manufacturers rely on U.S. 

businesses for installation and marketing support. 

The market research report prepared for EPA by Frost and Sullivan2 indicated that 730 masonry 

heaters are installed yearly in the U.S. with total revenue of $6.6 million. Although masonry 

heaters accounted for only 0.1% of the analyzed hearth units sold, they accounted for 1.3% of 

total hearth revenue. Taking in to account that more than one of these 250 businesses may 

typically handle each unit through its manufacture, sale and installation, the average business 

involved in the masonry heater industry certainly deals with fewer than three units annually. 

Regarding the particulate emissions impacts of masonry heaters, the White Paper concluded: 

 

1

 Ferguson, R., A Report on the Particulate Emissions Performance of Masonry Heaters – Definition, Data, Analysis 

and Recommendations, February 13, 2008 

2

 Frost and Sullivan; Project: Market Research and Report on North American Residential Wood Heaters, 

Fireplaces, and Hearth Heating Products Market (P.O. # PO1-IMP403-F&S), Final Report, EPA, April 26, 2010, pp. 

31-32. 
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The test data support previous conclusions regarding the particulate emission performance of 

masonry heaters as a class and further defined as those designs that meet the criteria outlined 

earlier in this paper. Using a variety of test procedures, fueling protocols and fuel types, 

emission measurement methodologies, laboratory and in-situ measurements, the resultant 

average particulate emissions have ranged from 1.4 to 5.8 grams of particulate per kilogram of 

fuel burned. The average of the averages for this data is 2.9 g/kg. Again, the current AP-42 

emission factor for masonry heaters is 2.8 g/kg. 

The low average particulate emissions from masonry heaters combined with the small number of 

annual installations justifies allowing masonry heater installations to continue without imposing 

undue burdens on the installers of these appliances. The cost associated with testing individual 

masonry heaters is simply prohibitive and does not represent a needed expenditure to protect air 

quality. Another means of satisfying air quality regulators is appropriate in this case. 

Masonry Heater Definition 

Definitions of the appliance category from three sources are presented below: 

1. From the February 2008 White Paper: 

“A masonry heater is a site-built or site-assembled, solid-fueled heating device constructed 

mainly of masonry materials or soapstone in which the heat from intermittent fires burned 

rapidly in its firebox is stored in its massive structure for slow release to the building. It has an 

interior construction consisting of a firebox and heat exchange channels built from refractory 

components.” 

Specifically, a masonry heater has the following characteristics: 

• Site-built or site-assembled. 

• A mass of at least 800 kg. (1760 lbs.). 

• Tight-fitting fuel loading doors that are closed during the burn cycle, 

• An overall average wall thickness not exceeding 250 mm (10 in.). 

• Under normal operating conditions, the external surface of the masonry heater, except 

immediately surrounding the fuel loading door(s), does not exceed 110 C. (230 F.). 

• The gas path through the internal heat exchange channels downstream of the firebox 

includes at least one 180-degree change in flow direction, usually downward, before 

entering the chimney. 

• The length of the shortest single path from the firebox exit to the chimney entrance is at 

least twice the largest firebox dimension. 

• A combustion air control that is designed to provide a high-fire burn rate only. 

• A combustion air introduction system that directs the majority of the combustion air to 

the area in the firebox that is at or above the level of the fire. 

• Constructed or installed by qualified masonry heater builders. 
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ASTM E-1602 “Standard Guide for Construction of Solid Fuel Burning Masonry Heaters” 

provides design and construction information for the range of masonry heaters most commonly 

built in the United States and can be used as the basis for determining whether a particular design 

qualifies for recognition as a masonry heater.” 

2. From the NSPS Regulated Product Applicability/Definition Proposal submitted to EPA by 

HPBA in June 2011: 

“Masonry heaters are site-built (using local materials or a combination of local materials and 

manufactured components) or site-assembled (using manufactured components), solid-fuel 

burning heating appliances constructed mainly of refractory materials (e.g., masonry materials 

or soapstone) in which the heat from intermittent fires burned rapidly in their fireboxes is stored 

in their refractory mass for slow release to building spaces. They typically have an interior 

construction consisting of a firebox and heat exchange channels built from refractory 

components, through which flue gases are routed. ASTM E-1602 “Standard Guide for 

Construction of Solid Fuel Burning Masonry Heaters” provides design and construction 

information for the range of masonry heaters most commonly built in the United States. The 

site-assembled models are generally listed to UL-1482.” 

3. From a consensus recommendation of the Masonry Heater Association (MHA) and 

Association of Masonry Heater and Oven Professionals (AMHOP). 

Appliances considered under this regulation shall conform to the definition of ASTM 1602, 

Section 3.2, “Definitions of Terms Specific to This Standard: Masonry Heater”. 

“Masonry heater” will be considered to include: 

Complete solid fuel burning appliances conforming to a masonry heater design, or 

a set of critical components necessary for construction of a masonry heater design to which 

commonly available masonry or other materials are intended to be purchased separately and 

added for installation, or custom and other units built on site from common local or other 

components to a masonry heater design. 

Determining Best Demonstrated Technology (BDT) for Masonry Heaters 

There are two components to a Best Demonstrated Performance analysis: a determination of the 

level of emissions performance that is technologically feasible, and an evaluation of the costs of 

achieving the various levels of control that are determined to be technologically feasible. The 

decision on a performance standard reflecting BDT involves an integration of the results from 

these two analyses. Both components are addressed below. 
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I. Technological Feasibility 

A. Emission Standard paired with Approved Test Method(s) 

For a broad range of masonry heater designs built or installed in North America, the traditional 

NSPS approach of testing a representative example to determine whether it meets an emission 

standard would be appropriate. Once the design has been approved, other units with the same or 

substantially similar designs would be presumed to perform the same, thus allowing the testing 

cost to be distributed over multiple installations, just as is done for other NSPS source categories. 

This approach requires decisions to be made on (1) a test method or methods, (2) the format of 

the emission standard (e.g., g/hr, g/kg or g/MJ), and (3) a numerical value for the performance 

standard that reflects best demonstrated technology. Each of these issues is discussed in turn 

below. 

(1) Test Methods 

Masonry heater emission testing that has been conducted over the past 20 years has employed a 

variety of laboratory and in-situ testing protocols. This includes variations in both the fueling 

procedure and the way particulate emissions were measured. Recent activity within the ASTM 

test method development forum has resulted in a new consensus-based test method for masonry 

heaters, ASTM E2817-11, which has been approved and published. This method is intended to 

be used in conjunction with ASTM E2515, Standard Test Method for Determination of 

Particulate Matter Emissions Collected by a Dilution Tunnel. Since ASTM E2817-11 is a 

recently established, consensus method for testing these appliances, it is the clear choice for a 

test method for use in this component of the NSPS. 

There is currently no consensus-based masonry heater efficiency test method in use in North 

America. Limited efforts have been made to adapt the CSA B415.1-2010 stack loss method for 

use with masonry heaters. The technical hurdle is that the B415.1 calculation algorithm requires 

that the weight of fuel consumed for each sampling interval be known. This is because the 

algorithm is based on a mass balance principle. However, masonry heaters often exceed the total 

mass that can be accommodated by test laboratory platform scales for determining the 

incremental fuel load weight losses during the test run with the degree of resolution and accuracy 

needed for the CSA B415.1 calculation process. Efforts to model the typical weight loss pattern 

in masonry heaters (as a way to provide the needed fuel weight inputs for the CSA B415.1 stack 

loss method) or to adapt a variation of the Total Combustible Carbon (TCC) efficiency method 

(which works without fuel weight inputs) have been explored, but have not yet begun to be 

considered in any consensus-based standards development process. Either approach will require 

confirmation testing across a range of typical masonry heaters as the essential predicate for 

establishing an efficiency test method for use in a regulatory program. 

EPA should continue to encourage the development of a workable and reliable masonry heater 

efficiency test method. With adequate lead time to allow the work to come to fruition, overall 

efficiency could be required to be reported as part of masonry heater certification testing and 

labeling rather than as part of the emission performance determination. This would adequately 
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serve the purpose of providing consumers with the information that might be useful when 

deciding if a masonry heater is right for them or which model they should choose. 

(2) Format of the standard 

As far as format of the standard is concerned, there really are only two available choices: fuel 

mass-based emission factor (g/kg) and emission rate (g/hr). Historically, the g/kg format has 

been the standard way to report and rank emissions from masonry heaters, and is used in the two 

state regulatory programs for these heaters (Colorado and Washington).3

 Testing to determine 

compliance with those programs has been the source of much of the available in-laboratory data. 

To quote from the White Paper regarding format of the standard: 

“This format [g/kg] provides the best way to compare emissions from high-burn-rate, highcombustion-efficiency, intermittently-fired appliances. Emission rates, when available in the 

reports, have also been provided. However, as was briefly discussed in the background section, 

emission rates (grams of particulate per hour) can be deceiving when evaluating intermittently 

fired high-mass appliances. One or two fires that last only a few hours can provide heat for a full 

twenty-four hour period. Emission rates should therefore be normalized over the period of time 

that heat is being provided by the masonry heater if they are to be used to compare different 

appliance types.” 

The other possible format, g/MJ or lb/MMBtu output, is simply not an option at this time, as 

there is currently no consensus-based North American test method for determining masonry 

heater efficiency, and, for that reason, no efficiency database for this category of appliances. See 

discussion in the previous section. 

 

 

3

It has been learned that EPA will solicit public comment on whether the format should include a g/hr emissions 

cap, with 7.5 g/hr from the non-catalytic woodstove phase 2 standards offered as a “straw man.” As the above 

quote from the White Paper points out, masonry heaters and woodstoves have entirely different use patterns, and 

that completely undermines any attempt to reason by analogy from one appliance category to the other. High 

combustion efficiency, single burn rate, intermittently fired appliances are not an appropriate candidate for 

regulation using emission rates, whether or not this format is appropriate for woodstoves. In any event, the “cap” in 

the phase 2 woodstove standards had as its rationale providing additional incentives to assure more uniform 

emissions performance across the four required burn rates [“The Phase II caps for individual runs are designed to 

assure that the emission control performance of wood heaters is relatively constant across the full range of 

operating conditions.”, Preamble to Subpart AAA Proposal, 52 Fed Reg 4994, 5008 (February 18, 1987.], a 

rationale that has no place in the discussion of the format for masonry heater standards, which operate at a single 

(high) burn rate. And the cap in the Phase 2 woodstove standards is 15 g/hr; 7.5 g/hr is the weighted average 

emission rate that non-catalytic woodstoves need to achieve across four required burn rates to be certified. Even if a 

“cap” were an appropriate standard component for masonry heaters, the level of the cap would have to be 

determined rigorously from the masonry heater data base, as part of the BDT determination; the Phase 2 woodstove 

cap would be entirely irrelevant to this analysis, as it is based on a BDT analysis for an entirely different appliance 

category. 
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(3) Performance Standard Reflecting BDT 

The matter of defining BDT for masonry heaters is somewhat confounded by the variety of test 

methods used to generate the available data. As mentioned previously, several emission 

measurement methods and fueling protocols have been employed. These have encompassed 

both in-situ and laboratory testing. The emission sampling methods have included the 

ESS/AWES type stack sampling (where intermittent samples are drawn at prescribed intervals) 

to dilution tunnel sampling following EPA Method 5G and more recently, ASTM E2515. The 

fueling protocols have ranged from cordwood burned in homes by the users to several variations 

of Douglas fir crib configurations as well as several species of cordwood burned in a laboratory. 

Some of the most recent laboratory testing has been conducted using the new ASTM masonry 

heater test method cordwood protocol comparing the results directly to testing using the two new 

ASTM crib wood protocols4

. 

Although the fueling protocols in the new ASTM test method (E2817-11) should be very 

representative of the way masonry heaters are burned in homes and this method represents the 

long sought consensus on how to best test masonry heaters in the laboratory, the method has not 

been widely used at this point. The most recent data is from the in-house laboratory of the 

largest producer of masonry heaters where they tested a number of their own models. 

Correlation between the preponderance of the existing data and data from the new ASTM test 

method is limited at this point but is presented in Table 1. Establishing a robust correlation 

would require re-testing of a significant number of previously tested masonry heater models to 

directly compare the old and new results. The costs of such a test program are simply 

prohibitive. 

It is therefore necessary to rely on what new data is available in combination with older data. 

For standard setting purposes, this approach implicates developing a data set incorporating the 

new data from the ASTM method and data from previous testing with methods which are 

reasonably similar to the ASTM method. These data can then be statistically analyzed and an 

emissions performance value selected that provides an appropriate margin of compliance, to take 

into account both the fact that robust correlation between the new ASTM test method and the 

methods used to generate the current data base has not been established, and also to take into 

account the fact that the precision of the new ASTM test method has not been determined. That 

discussion follows. 

For purposes of this discussion, the known data can be categorized in three subsets. Attachment 

A is the compilation of data for testing conducted between 1990 and 2006 that was presented in 

Attachment 6 of the White Paper. Attachment B are test results from more recent testing 

including all known data using ASTM 2817-11. Attachment C1 is a data summary table from a 

report from the Lopez Labs Co-operative that includes results from testing a single heater using 

the Condar® sampling device while C2 shows comparative data between Condar® and ASTM 

E2515 for two test runs. 

 

4

The crib fueling method in ASTM E2817-11 Annex A2 addresses “bottom-up” combustion while Annex A3 

addresses crib fueling for heaters employing “top-down” burning. Annex A1 is the cordwood protocol.
Page 8 of 23

When screening the available data with the intent to use datasets that are consistent with the new 

ASTM masonry heater test method and ASTM E2515, or that was generated by what can be 

considered close surrogates for those methods, much of the available data must be set aside. The 

in-situ testing does provide a direct measurement of field performance but the lack of data to 

correlate these results to the new test method precludes its use for determining BDT. The ESS 

sampling protocol used for Colorado and Washington State testing is significantly different than 

the dilution tunnel methods and only limited testing has been done to establish correlation with 

other methods. Similarly, EPA has stated its objections to the OM-41(Condar®) sampling 

method5

 for use in a regulatory program and we are not aware of any change in that position. 

Consequently, that data must also be set aside for BDT purposes. It is not to say that the in-situ 

data and Condar® data cannot serve a useful purpose in the discussion. They can be used as a 

qualitative check for any proposed definition of BDT and to insure that adequate compliance 

margin is included in the passing grade. 

When we apply this screening concept we are left with a somewhat limited amount of usable 

data. The following figures show the datasets for laboratory tests conducted using dilution 

tunnel sampling, together with a statistical analysis. Figure 1 shows the results of tests using 

cordwood fuel while the Figure 2 shows the result from using crib fuel. 

 

5

 Federal Register/Vol. 53, No. 38/Friday, February 26, 1988/Rules and Regulations , pp. 5866-5867( rejecting 

requests to allow use of OM41 in the NSPS program, finding “a number of technical deficiencies” with the 

method.) 
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Figure 1 
Page 10 of 23

Figure 2 

The Student’s T distribution is applied to the data since there are so few data points. To 

determine the upper value at a 95% confidence level, a “p” factor is first determined from 

standard tables based on the degrees of freedom associated with each dataset. The standard 

deviation for the dataset is multiplied by the “p” and added to the mean to determine the upper 

value for the 95% confidence interval. Since we are interested only in the upper confidence limit 

in terms of the impact on an NSPS passing grade, one-sided “p” values were used. In both cases, 

the 95% confidence intervals established using this procedure are less than the often-cited two 

standard deviations typically used to describe the 95% confidence interval. 

The upper value determined for the cordwood tests using ASTM E2515/EPA M5G is 3.65 g/kg. 

Using various crib protocols, but again using dilution tunnel sampling, the upper value is 2.85 

g/kg. These values are not too dissimilar considering the differences in the appliances and 

fueling as well as different laboratories conducting the tests. 

It is recommended that the 95% upper confidence level for cordwood be considered as the basis 

for determining BDT. But, additional compliance margin must still be included in any NSPS 

passing grade to address the potential test method variability that cannot be determined without 

data from a properly designed study. A discussion of that issue follows. 
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Very little is known about the precision of any of the methods that have been used to test 

masonry heaters. We have to assume a certain level of variability is simply unavoidable since 

wood is being burned under natural draft conditions. This variability can be predicted by using 

components of the EPA Wood Heater Test Method Variability Study6. Part of that study 

examined potential sources of variability in EPA Method 28. Table 4 on page 17 of the report 

shows the variability in the high burn rate results for several of the round robin wood heaters. 

The average coefficient of variation (standard deviation divided by the mean) for the measured 

maximum burn rates is 20%. Although we know that masonry heaters are different in many 

ways from wood heaters, the maximum burn rate variability demonstrated during round robin 

testing by the wood heaters at a fixed maximum combustion air setting should give an indication 

that similar variability in burn rate could be expected from fixed burn rate masonry heaters if 

enough tests are conducted to allow even a simple statistical analysis. And by looking deeper at 

the wood heater round robin results for the high burn rate tests, it is possible to gain some insight 

into what might be expected for emissions variability for masonry heaters. For example, if you 

examine the maximum burn rate test results for non-catalytic model 3, which span multiple years 

of testing of the same exact heater in several different test labs, you will see that the variations in 

both the observed maximum burn rates and the particulate emissions at the maximum burn rate 

are wide. And this difference is not just between different labs in different years, this variability

exists within the same lab during the same proficiency test series. Figure 3 shows this variability 

with emissions converted from g/hr to g/kg to better relate the results to masonry heaters. 

 

6

Curkeet, R. and Ferguson, R., EPA Wood Heater Test Method Variability Study, Analysis of Uncertainty, 

Repeatability and Reproducibility based on the EPA Accredited Laboratory Proficiency Test Database, October 6, 

2010.
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Figure 3 
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Note: The laboratory letter codes may apply to different labs in different years. 

Figure 4 presents the same data but looks at the variation in burn rate and emissions using simple 

statistical analyses. The coefficient of variation for both the burn rate and the emissions are 

significant and indicative of how much the variability can be expected when burning the same 

heater multiple times at different labs. In this case, the coefficient of variation for the burn rate

was 33% while the coefficient of variation for emissions was 49%. Analysis of other (meaning 

those models where adequate data is available) non-catalytic heater models used in the round 

robin test program show coefficients of variation for maximum burn rate ranging from 10% to 

33% and for particulate emissions ranging from 27% to 76%. 
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Figure 4 
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Even if we postulate that masonry heaters are significantly less variable in their operating 

characteristics than a non-catalytic wood stove fired at the maximum air setting, the ranges 

observed in the laboratory proficiency test round robin still can provide useful insights into the 

expected variability in masonry heater emissions testing. It is simply reasonable to expect that 

masonry heaters will not be immune from the variability shown to exist when burning wood. 

Adding a compliance margin of at least 25% to the passing grade is warranted based on the 

preceding analysis of the maximum burn rate data from the EPA woodstove proficiency test 

round robin. This would increase the proposed passing grade to 4.3 g/kg. 

The in-situ, Colorado/Washington State ESS and Lopez Co-operative Labs Condar® datasets 

show a range of emissions performance from 0.5 to 6.2 g/kg. As noted previously, these data 

can’t be used quantitatively, because the methods are too dissimilar to ASTM E2817-11 and 

ASTM E2515. However, they do provide a qualitative insight into the possible range of PM 

emissions performance that might be expected in a more comprehensive E2817-11 data set. 

B. Demonstrating Compliance with the Performance Standard using Demonstrated Parameterbased Approaches. 

A different approach for determining compliance with the NSPS performance standard is 

justified for the sub-set of masonry heaters designs that fall within the parameter ranges that have 

been shown to provide emission performance that is equivalent to previously tested models or 

otherwise verified by testing. 

Modeling/calculation approaches present an opportunity to certify masonry heater designs that 

fall within established parameter limits without the need for additional emissions testing. 

With EN15544, the Austrians have already adopted this approach for certain custom-built 

masonry heaters. The design is considered to conform (meaning meeting emission limits) if, 

after entering the individual design parameters into the model, the algorithm determines that the 

combination of parametric values predicts that emissions will fall below the established limits. 

The Austrian trade association “Kachelofenverband” devoted the resources to research, develop, 

and extensively test7

this mathematical model of particular masonry heater materials and designs. 

By testing heaters within the parameters of the model, it was found possible to establish 

emissions performance for the entire modeled class. The basic theory and formulae are 

embedded in a public standard which was balloted under the European Union committee CEN 

295 and approved in 2009 as a consensus-based EU standard (EN15544) for broader European 

use. The Kachelofenverband went further to place this standard within its own licensed software 

as part of a verification program. Masonry heaters can be designed under EN15544’s provisions 

and once verified as conforming are certified without further testing as meeting not only the 

 

7

 Schiffert, Dr. Thomas; Schriftreihe Nr. 5 “KACHELOFEN 2000-Technishe Entwicklungen der 

Holzverbrennungen im Kachelofen (Script Series #5 “Tiled Stove 2000-Technical Development of Burning Wood 

in Tile Stoves)”, Ősterreichischer Kachelofenverband, January 1996. 
Page 16 of 23

European Union emissions standards but also the more restrictive Austrian standards for carbon 

monoxide, nitrous oxides, organic hydrocarbons and particulates8. 

The effort to translate and incorporate this EN standard into an ASTM standard for masonry 

heaters has yet again been delayed despite successful balloting, because of legal issues between 

the European standards organization and ASTM regarding the latter’s use of copyrighted 

material. How to best proceed to establish a North American adaptation of the EN 15544 

calculation procedure is still under consideration. However, since EN 15544 is an established 

standard available for use by masonry heater manufacturers where applicable to their heater 

designs, delays in the resolution of the ASTM/EN copyright issues should not prevent 

incorporation of this standard in the NSPS. 

At this time there are limited data showing the emissions performance of masonry heaters that 

have passed or would pass the EN 15544 requirements utilizing North American masonry heater 

test procedures. One unit that is certified in Europe using EN 15544 was tested using both the 

cordwood and crib fuel procedures from the final draft of what would become ASTM E2817-11 

as well as the Colorado fueling protocol. The results are shown in Figure 5. Model 4D is the 

same as shown in Figures 1 and 2. The emissions performance of this heater design ranks it 

among the cleanest masonry heaters. 

Figure 5 

Two other models that were close to achieving a passing status when evaluated by the EN 15544 

calculation procedure were also evaluated using the ASTM E2817 cordwood and crib fuel 

protocols as well as the Colorado fueling protocol. Exhaust passage configurations in these 

models, which were modified from the European designs to provide more venting flexibility for 

the North American market, were the reason they did not meet EN 15544 requirements. Firebox 

and combustion-related components were within the allowable parametric ranges. These designs 

would require only slight modification to fully comply with EN 15544. The test results from 

these units are shown in Tables 1 and 2 as Models 1A and 2B. All test results were under 1.5 

g/kg. The fact that these units are slightly outside the allowed EN 15544 parameter ranges, but 

still easily pass the proposed NSPS performance standard provides further support for including 

EN 15544 in the NSPS as an alternative method for demonstrating compliance, as it indicates 

that the NSPS performance standard compliance isn’t particularly sensitive to precise 

compliance with the EN 15544 algorithm. 

 

8

 Hofbauer, Dr. H. and Padouvas, E.; “Report about the Test of the Guideline ‘Kachelofen (tiled stove) with 

Standard Combustion Chamber’”, Technical University of Vienna, December 14, 2001. 
Page 17 of 23

In addition, qualitative support for the suitability of EN 15544 for use as an alternative NSPS 

compliance procedure is provided by test data from two other units. Inputting the parametric 

information for the Royal Crown masonry heater that has been installed in North America for 

many years shows that it would meet the requirements for European certification using EN 

15544. This model has not been tested to the new ASTM E2817 test procedure but does have insitu test data (owner operated using cordwood) from testing conducted in 1991-1992. This data 

is shown in Attachment A, Reference C with emissions reported at 1.4 g/kg. The Biofire was 

also tested in-situ during the 1991-1992 test series. The reported emissions were 1.9 g/kg. It has 

been indicated by the importer that the successor model, which is similar in almost every way to 

the tested model in-situ is EN 15544 certified. 

Other parametric alternatives to emissions testing should also be considered, including those 

currently in use by Washington State9

 and Colorado10. These alternate certification options 

employ a “substantially similar” evaluation conducted by an approved laboratory where critical 

design parameters must be within prescribed limits when compared to previously tested and 

certified models. We suggest that EPA discuss the details of the “substantially similar” options in 

their rules with Washington State and Colorado air quality officials. 

And the door should remain open for other modeling approaches after adequate confirmation has 

been achieved. Modeling-based procedures for determining compliance with NSPS emission 

limits are a way of reducing the regulatory burden on masonry heater builders while still 

maintaining a high degree of confidence that masonry heaters that conform to the prescribed 

modeling requirements will satisfy the NSPS performance standard. 

II. Cost Analysis 

This component of the BDT analysis requires information on the costs associated with the 

various levels of control that were determined to be technologically feasible. As discussed 

above, there are a number of masonry heater designs, all or almost all of which can be regarded 

in some way as “clean burning.” What is lacking, however, is a comprehensive ASTM E2817-

11 database on the emissions performance of these designs to permit an analysis of which 

designs would be included and which ones would be excluded if the “straw man” passing grade 

developed in the above analysis were adopted as BDT. For this reason, the cost analysis 

component will have to be deferred until significantly more ASTM E2817 data are available. 

 

9 Washington State Building Code/Chapter 51-50 WAC/WAC 51-50-31200 /Washington State Building Code 

Standard 31-2/ STANDARD TEST METHOD FOR PARTICULATE EMISSIONS FROM FIREPLACES 

(See Section 2114, International Building Code), SECTION 31.205 — APPROVAL OF NON-TESTED 

FIREPLACES. 

10 DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT /Air Quality Control Commission 

/REGULATION NO. 4 /CONCERNING THE SALE AND INSTALLATION OF WOOD-BURNING 

APPLIANCES AND THE USE OF CERTAIN WOOD-BURNING APPLIANCES DURING HIGH 

POLLUTION DAYS /5 CCR 1001-6, Section 3.2
Page 18 of 23

These data will also, of course, permit the technological feasibility analysis to be refined, as 

pointed out in the previous section. 

Small Producer Exemption 

The White Paper as well as the SBREFA submittals and the Frost and Sullivan market analysis, 

all previously referenced, support the fact that the vast majority of companies that install 

masonry heaters are very small businesses. 

EPA has supported the concept of a small producer/installer/builder exemption with an annual 

cap. This concept is sound as it addresses the undue regulatory burden on these businesses with 

very little or no adverse environmental impact. It has already been established that masonry 

heaters, as a class, are very clean burning. It has further been established that most masonry 

heaters involve the site-assembly of pre-manufactured components rather than being one-off 

custom designs. 

What is proposed is that individual masonry heater business entities that are “small businesses” 

under the SBA definition be allowed to build/install up to 12 uncertified masonry heaters per 

calendar year. These heaters would be exempt from the performance requirements of the NSPS, 

however, specific record-keeping requirements would still be in force to allow determination that 

those business entities are in compliance with the terms of the exemption. The record-keeping 

would include the name of the owner, location of the heater and the date the installation was 

completed. 

For any given business entity, installation of any certified masonry heaters during a given 

calendar year would not count against the 12 heater exemption allowance. 
Page 19 of 23

Attachment A: Masonry Heater Test Data, 1990 - 2006 
Page 20 of 23

Attachment B: Masonry Heater Test Data: 2008 - 201211,12

 

11 Seaton, T, Recent Masonry Heater Test Results, July 2011 

12 Tulikivi In-House Data, April 2012 
Page 21 of 23

Attachment C1: Condar® Test Results 13, 14

 

 

13 Senf, N. and Chernov, A., Lopez Labs Co-operative, Summary of Masonry Heater Emissions Tests, Table 2, 

Data Summary, July 17, 2010 

14 It should be noted that the data in this summary of Condar® test results on a single masonry heater encompasses 

several fueling and operating parameter variations. The mean of all data is 1.29 g/kg with a standard deviation of 0.7 

g/kg. No other evaluation of this data has been conducted by the authors of this proposal. 
Page 22 of 23

Attachment C1 (Continued) 

Key: 

PM factors less than 1 g/kg are highlighted in green 
Page 23 of 23

PM factors between 1 – 2 g/kg are in white 

 PM factors greater than 2 g/kg are highlighted in brown 

Attachment C2: Test Method Comparisons15

 

15 Senf, N. and Chernov, A., Lopez Labs Co-operative, Summary of Masonry Heater Emissions Tests, Table 1, 

OMNI Test Results, July 17, 2010