Monday, March 29, 2021

Veteran lab technician challenges Alaska's wood stove criteria

Ben Myren, left, with Larry Brockman
at the 2018 Stove Design Challenge
where the IDC was showcased.
Updated, April 2, 2021 - Ben Myren, one of the nation's most experienced wood stove test lab experts, is frustrated with the officials in Alaska that are trying to enact stricter wood stove standards.  Fairbanks has to design a State Implementation Plan (SIP), to clean up their air to meet federal air quality limits or face sanctions. 

Myren is not alone in his opposition to the way Alaska is seeking to crack down on more polluting stoves.  Nineteen entities responded to the EPA's public comment on the Alaska stove requirements and all 19 were very negative.  This is not entirely surprising considering all 19 comments came from the wood stove industry, mainly from manufacturers.  Their comments can be viewed here and Myren's comments are reproduced below.  Companies that commented against the ADEC proposal included HHT, US Stove, Jotul, Rais, Blaze King, Central Boiler and Woodstock Soapstone.

The Alaska Department of Environmental Conservation (ADEC) stove requirements resulted from  a novel and ambitious review of certification reports of all wood stoves. According to its reports, the agency found missing and flawed data in nearly every set of certification papers sent to the EPA by EPA approved testing labs. One of those labs, run by Ben Myren, provided scores of reports ADEC found to be deficient.

Following ADEC's review, the Northeast States for Coordinated Air Use Management (NESCAUM), a non-profit based in Boston, used that data in a scathing report that found the EPA's system of certifying wood and pellet stoves boilers and furnaces to be "dysfunctional." Currently, high level officials at the EPA are reviewing the NESCAUM report and the stove industry and states are waiting to see what parts of the report the EPA will address and how. In the meantime, the EPA has reportedly stopped processing certification paperwork.

The stove industry association, the Hearth, Patio & Barbecue Association (HPBA) dismissed the NESCAUM report in a blog by John Crouch, their Director of Public Affairs, saying they do not see "any indication that the regulatory process doesn't work." Instead, Crouch says that the report is the result of an "anti-woodstove agenda" and its authors are trying to "find a problem so that they can push for their desired outcome." The Alliance for Green Heat's response urged the EPA to "take the report seriously", and calls on the Biden Administration to provide more resources for implementation and enforcement. AGH was critical that the report failed to sufficiently distinguish the far more fair and reliable testing of pellet stoves and boilers, which could undermine important efforts of New England states to incentivize modern pellet heating as a means of reducing fossil fuel reliance.

Myren, and most of the manufacturers who commented objected to virtually all the keys ways Alaska is trying to require stricter standards in their effort to convince the EPA that they are addressing its air pollution non-attainment problem. The EPA accepted Missoula's strategy of simply banning new installations of wood stoves and limiting pellet stove installs to devices emitting 1.0 g/h or less. Missoula's 1.0 g/h limit was also enacted ex post facto, and did not give manufacturers the chance to meet the stricter local standard in advance. Myren notes that Alaska's requirement that stoves not emit more than 6 g/h during the first hour of a test to be sold in Fairbanks is unfair, including because some stoves test with a cold start and capture heavy start-up emissions while others test from a hot start. 

ADEC points out that the strong objections posed in all the industry comments may backfire, because if the EPA rejects ADEC's approach, the fallback may be simply ban the installation of new cord wood stoves, like Missoula did.  The EPA approved Missoula's strategy and ADEC is using that as a yardstick to craft something that may be equally effective at reducing wood smoke, but still allow Fairbanks residents to install more cordwood stoves. 

Myren also found that ADEC appears to be requiring more bark on the test loads of cordwood for the ASTM test than for the Integrated Duty Cycle (IDC) test it asked the EPA to approve. Thus, if a lab uses the IDC method to certify a stove, it may fail ADEC's criteria. If Fairbanks wants a test method that will help identify stoves that will perform well in that polar-like environment, Myren argues that the IDC fails on many counts. In fact, Fairbanks may do better to alter the IDC to test stoves for their ability to burn in sub-zero temperatures, which causes a much higher draft than used in the IDC.





86 FED. REG. 10,511 (FEB.22, 2021)


     The US EPA is proposing to approve parts of the Alaska State Implementation Plan for the Fairbanks North Star Borough Area (NSSIP).  Part of the NSSIP includes revised emissions standards and, possibly new test methods, for wood stoves.  Myren Consulting, Inc. (MCI) would like to offer the following comments on these proposed actions.


     1. EPA’s initial choice of the 2.5 g/h particulate emissions (PM) standard for wood stoves tested with cord wood (the cord wood option, see Section 60.532(c) in the 2015 NSPS) was made without any supporting data that demonstrated that the 2.5 g/h standard related in any way to the crib fuel standard of 2.0 g/h.  (See Section 60.532(b) in the 2015 NSPS.)  In short, EPA never conducted any M301 Validation tests to compare the emissions from the 2 different test methods (EPA M28/ M28R and ASTM E3053) used to determine PM emissions from wood stoves.  Thus, any use of the 2.5 g/h standard in the deliberations that led to the content in the NSSIP is both arbitrary and capricious.


            2. The Alaska Department of Environmental Conservation’s (ADEC) choice of a 6.0 g/h PM emission limit has also been made without any similar supporting data.  Thus it is also arbitrary and capricious.  


3. The 6.0 g/h PM emission limit is also arbitrary and capricious because it does not differentiate between the two test methods, EPA M28/ M28R and ASTM E3053, presently being used to certify wood stoves.  The operating and fueling protocols in these two test methods are very, very different.  The EPA M28/ M28R requires hot to hot tests for all tests with the crib fuel loads made from dimensional lumber (2x4’s and 4X4’s) that uses a loading density of 7 lbs. ±10%.  ASTM E3053 requires a cold to hot start for the High burn, hot to hot starts for the Medium and Low burns.  The fuel used in ASTM E3053 is cord wood with a loading density of 10 lbs. ±5% for the High burn and 12 lbs. ±5% for the Medium and Low burns.  Just the difference in fuel type (crib fuel vs. cordwood) and loading densities (7 lbs. ±10% vs. 10 lbs. ±5%/ 12 lbs. ±5%) would suggest that the 6.0 g/h limit can not be applied evenly to these two methods. 


4. Given the way the stoves burn during these tests, especially for the ASTM E3053 cold start High burn, the 60 minute filter pull 

happens at very different times in terms of what is taking place in the firebox.  On smaller stoves being tested with ASTM E3053, it is very possible that the filter changed at 60 minutes will contain all of the emissions from the cold start (K/S) phase plus a portion, the dirtiest portion that includes coal bed leveling, loading and ignition of the High burn fuel load.  Here again, the failure to differentiate between what is happening in the firebox on stoves of different sizes renders the 6.0 g/h unfair and arbitrary and capricious.


5. The same is true for the larger fuel loads required in the ASTM E3053 tests, i.e., higher loading densities means larger/heavier fuel loads, which take longer to ignite, so the emissions will understandably be higher during the first 60 minutes.  Again no differentiation, which is unfair, arbitrary and capricious.


     6. The 6.0 g/h 60 minute PM emission limit is being applied in an ex post facto manner.  Had manufacturer’s known about this limit in advance, they would have had the opportunity to change their wood stove designs and bring their stoves into compliance.  However, that is not the case with the presently proposed rules because the 6.0 g/h rule is being applied to stoves already certified.  That, again, is grossly unfair, not to mention arbitrary and capricious.  


     7. The ADEC’s certification stove review process is horribly skewed, because it requires documents that were never previously required in the EPA certification process.  Here I am referring to the newly required documents titled “Document of Run Appropriateness”, “Document of Run Validity”, “Document of Run Anomalies” and “Document of Run Burn Rates”.  These documents are nothing more than “boilerplate” and do nothing to effect the actual test results.  Again, this is grossly unfair, not to mention arbitrary and capricious. 


8. In addition, the ADEC review criteria often establishes other new criteria that, in effect, establish new more stringent criteria that must be met before a stove can obtain ADEC approval.  One of these is the establishment of an undefined requirement for the medium dry burn rate for cord wood stoves.  The question asked in the ADEC’s Summary of Review” in the “Comments” section is essentially, “Why is this Medium primary air control setting representative of what is needed for a Medium burn?”  Yet the data presented show that the dry burn rate in the test report meets the requirement set forth in the test method.  Thus, the ADEC is revising test criteria after the fact.  Again this is grossly unfair, not to mention arbitrary and capricious. 


9. Similarly, the ADEC’s Summary of Review for wood stoves certified with cord wood using ASTM E3053 seems have a minimum requirement that at least 50% of one side of each fuel piece be covered with bark.  Yet that 50% requirement clearly contradicts what is found Section 3.29 in the recently approved Integrated Duty Cycle (IDC) test method (EPA Alternate Test Method ALT-140) which states in part:


“…Test fuel charge – the collection of test fuel pieces used in   each of the four phases of the test run.  L2, L3, and L4 require that at least 5% of the individual pieces with at least 80% bark on one side of the fuel piece…”  


 ASTM E3053 Section states that


“…Only cordwood pieces that are free of decay, fungus and

loose bark shall be used…” 


Thus there is no “official” bark requirement in the ASTM standard.


However, in as much as the ADEC requested approval of the AK version of the IDC contains the above cited bark requirement, it seems hard to believe that the ADEC would require an even more stringent bark requirement for stoves tested with the ASTM test method than is required in the IDC test method the ADEC requested EPA approve.  Or is this, once again, just one more instance of an unfair, arbitrary and capricious decision making process.


10. The IDC test method as presently written (Version V7B_2.23.2021 AK IDC) and recently approved by EPA as ALT-140 can not be used as it is written.  Thus any mention of the above cited document in the entire NSSIP document as a means to improve air quality in the North Star Borough is unwarranted.  You can’t cite what you can’t use.  And any use of data generated via testing with the above version of the IDC, or any unapproved version of the IDC for that matter is also invalid, because the test method can’t be used as written.


11. Despite claims to the contrary, the IDC test method does not in any way reflect a real world operating scenario.  This is especially true of the Fairbanks North Borough where typical winter subzero temperatures would find homeowners operating their stove with the primary air control (PAC) wide open, not closed to the minimum primary air setting as is required for well over half of the IDC test, i.e., in the IDC test the PAC is set at wide open for the cold start portion of the test and the first 50% of the High burn fuel load weight.  After 50% of the High burn fuel load has been burnt, the PAC must be set to the minimum air setting for the rest of the High burn and all of the Maintenance fire phase, i.e., no additional air is allowed when the Maintenance fire fuel load is loaded into the stove.  The PAC stays at the minimum air setting until the start of the Overnight fire phase, when the PAC can be opened to the maximum setting for the first 10 minutes of a test and then the  PAC must be returned to the minimum air setting and must stay at that setting for the rest of the test.  Does that sound like a typical operating scenario for a stove in the North Star Borough when the outside temperature is less than 10-20 degrees F? 


10. If one looks at the entire US in terms of wood burning, Fairbanks is an “outlier” due to the extreme temperatures that occur there.  Thus, the solutions for resolving the air quality issues for Fairbanks may have little or no relevance to resolving air quality issues elsewhere in the US.  EPA needs to recognize this “outlier” status if it should chose to approve any of the suggested proposals to reduce the PM emissions form wood stoves in the Fairbanks area. 


11. And lastly, no matter which of the present test methods, i.e., EPA M28/ M28R, ASTM E3053 or the AK IDC, one would decide to use, the stoves certified via that test method will not work well in the field because of the difference in the draft (static pressure (pg)) generated by a freely communicated lab chimney versus the draft that is generated by a real world chimney that vents into the outside air.  Here research has shown that the draft generated by a 28 foot chimney vented into outside air that is 10F can double the dry burn rate of a stove.  Imagine what would happen to the dry burn rate and stove emissions when the outside temperature is -40F.  The Europeans have long recognized this problem and so have induced a draft (12-14 Pa) during their emission testing.  Now they are working on a new test method where the draft is varied over the course of a test run, with the variation in induced draft being determined by 4 different variables, chimney height, outside ambient temperature, flue gas temperature and flue gas static pressure.  Again, failure to recognize the problems with existing test methods and try to eliminate one or more in favor a perceived “better” method ignores reality.  Especially when no actual field testing ahs been done to validate these assumptions, which renders any preference for a particular test method arbitrary and capricious.  


In conclusion, many of the criteria the ADEC wished EPA to approve are not based upon scientific data and facts, but instead are simply an arbitrary and capricious choice. 


Thank you for the opportunity to present this testimony.


Ben Myren, President

Myren Consulting, Inc.

512 Williams Lake Road

Colville, WA 99114

email: <>

Related stories

Alaska releases deficiency details on wood and pellet stove test reports (Nov. 2020)

Alaska building list of cleaner, properly certified wood and pellet stoves (Oct. 2020)

Thursday, March 18, 2021

Initial response from AGH on the NESCAUM report

 A scathing report, "Assessment of EPA’s Residential Wood Heater Certification Program," raises many important points but overstates its case and fails to acknowledge the advances in stove technology in recent decades. The report never acknowledges that pellet stoves operate more consistently in homes as they did in the lab, compared to wood stoves, for example. Moreover, the policies and interests of the northeast states represented by the report's author, NESCAUM, are undermined by a report that never acknowledges the important role that modern, automated wood and pellet heating have to reduce fossil fuel use and help combat climate change. The Alliance for Green Heat (AGH) is preparing a response to the NESCAUM report.

The report alleges that the EPA certification process is "dysfunctional," and its tone and content easily digestible by the media.  The process needs significant improvements but we need to also recognize what works and what has been achieved. It rightly points out the deficiencies of the so called "independent" third-party reviewers, lack of sufficient enforcement by the EPA, and certification paperwork that often lacks required detail. AGH urges the EPA to take the report seriously, and calls on the Biden Administration to provide more resources to enforcement, the Burn Wise program, and the development of a federal cordwood test method that integrates IDC concepts.  Many of the problems cited by the report are the result of budget cuts in an agency tasked with scores of vital air quality programs.

AGH urges states and the media to take this report with a grain of salt.  This report provides an opportunity to further educate state and local experts but the report should not undermine the important steps states have taken to incentivize modern, automated wood and pellet heating.  The process to certify pellet stoves and boilers in particular is a functional one and can be even more so with improvements.  

The complexity of writing test methods that hold up over time is also evident in some of the missteps by the very authors of the report.  Test labs that used a flawed IDC test method developed by NESCAUM resulted in mysteriously low efficiency numbers.  The lab now has to explain to EPA why they should be allowed to adjust their efficiency numbers.  Our point is that regulators and experts all over the country - including the authors of this report - are going through an important learning curve to better understand how to improve test methods and the certification process.  We urge all stakeholders in this community to approach this highly complex process with humility - and urgency - so that lasting improvements can be made.

Monday, March 15, 2021

An open letter to Mayors of Comox, Cumberland and Courtney about wood smoke

Dear Mayors Arnott, Baird and Wells,

As representatives of a pro-wood heating non-profit, the Alliance for Green Heat, we are writing to express concerns about information in the “Overturn the Ban” website.

We want you to know that there are many members of the hearth industry that support reasonable, health-based restrictions on wood stoves. We understand that the primary restriction in your towns are disallowing new installs of wood stoves, which is an imperfect, but reasonable strategy. Allowing or even requiring homes with existing stoves to upgrade to a new one and destroy the old one, is also reasonable. However, we do urge towns and cities not to restrict or ban the new installation of pellet stoves, as they burn consistently cleanly, something the Overturn the Ban site omits to mention. We also urge jurisdictions not to restrict or ban masonry heaters because they are typically very clean and efficient, though very expensive.

All renewables have limitations, and in communities with frequent inversions, wood stove installation and usage often need to be limited. Wood and pellet heaters have an important role to play in providing renewable energy in North America, but that does not mean they are well-suited for every community.  They are usually least well-suited in densely inhabited urban centers, but even in rural areas that experience frequent inversions, reasonable restrictions make sense.

The adjoining towns of Comox,
Cumberland and Courtney are at the  
center of this map on Vancouver
Island, British Columbia.

One troubling half-truth promoted by the website is that new wood stoves operate far more cleanly than old ones.  Any wood stove that is loaded with wet wood and/or not given enough air is more likely smolder  and thereby smoke terribly and easily emit 25 grams of PM2.5 per hour. Some estimates say that up to 50% of stove users do not use seasoned wood. An operator of a brand-new stove causing it to produce high emissions is unfortunately not a rare occurrence.  If an old and a new wood stove get the same dry wood or even semi dry wood, the new one will almost always burn cleaner.  However, that stove can still emit 5 grams an hour of PM or more, which is excessive during an inversion. 


New EPA regulations require that stoves not emit more than 2.5 grams an hour in a very controlled lab setting and in the hands of trained experts.  The EPA standard is not an estimate of emissions produced by homeowners, who may rarely achieve an average of 2.5 grams an hour. With pellet stoves, the emissions measured in the lab are consistent with the emissions in consumers' homes because the fuel is consistently dry and uniform, and the combustion chamber is automated.  


Masonry stoves tend to be consistently clean not just because of their design, which makes the fuel burn hot and fast, but also because of the culture of users of this niche technology. Their main distinguishing feature is the ability to store the heat from a short hot fire for slow release over a daily heating cycle. Seasoned cordwood burned this way has been demonstrated in real world testing to have PM2.5 emissions in the same range as pellet stoves


You should also know that most wood stove companies had a very good sales year in 2020, despite what they feared when Covid-19 began.  And, in the US Congress just passed a 26% tax credit for the most efficient stoves, so sales in the US by all the major manufacturers will be bolstered for the next three years.  


Possibly the top consumer education website on wood heat in North America is a Canadian one,  It wisely begins by saying, “wood heating can be done badly or well. Firewood can be harvested poorly, burned dirty and its heat wasted.”  Wood heating is done well depending on three things: a good stove, an experienced and attentive operator and seasoned wood.  


Please let us know if you have any questions and know that many of us who burn wood and pellets are responsible environmentalists.




John Ackerly,


Maryland, US


Norbert Senf

Chairman of the Board

Quebec, Canada