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.

 

MYREN CONSULTING, INC.

AIR PLAN APPROVAL; AK, FAIRBANKS NORTH STAR BOROUGH;

2006 24-HOUR PM_2.5 SERIOUS AREA PLAN

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 8.4.2.1 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: <myren.ben@gmail.com>

Related stories

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

AGH response to NESCAUM report on data from Alaska process (March 2021)

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

EPA finds lapses in cord wood certification test reports

A Regency stove being tested at RFS labs
for 2020 compliance using the Alternative
ASTM E3053 cordwood method. (NOTE: The
3 photos used in this story are NOT connected
to the EPA memo.  They are just random 
cordwood certification test.)

The EPA recently sent a memo to wood heater test labs and third party certifies about significant lapses in documenting certification tests using the cord wood test method and potentially significant lapses in cord wood testing.  We reproduce the memo below.  

[For the more recent blog on lab testing, 30-day notices and non-CBI reports, click here.]

The memo does not specify which labs and which manufacturers are involved and the EPA is not making that public as of now.  The manufacturers involved are being contacted to have labs submit paperwork to the EPA, via third party certifies, who also could have caught the lapses before forwarding documentation to the EPA.  Some stoves may have to do the cord wood emissions tests again.

A Kuma stove using the ASTM
test method at Omni labs

AGH supports a transition to cordwood testing under the assumption that stoves tested with cordwood are more likely to burn more cleanly in the hands of consumers. But cordwood testing of stoves in the United States is still in its infancy and so far there is only the ASTM E3053 test method.  There are still many, many questions about whether the ASTM method can help achieve the emergence of a class of wood stoves that truly operate better in peoples' homes.

AGH asked the EPA to provide us with the memo to test labs when we heard about it.  The EPA promptly sent it to AGH but more often than not, we do not know about memos that go to labs, HPBA and manufactures.  EPA rarely shares many

A Travis stove using the ASTM cordwood
method at Omni lab.

such memos with the wider stakeholder community, that also includes stove retailers, state air quality agencies and others.  We believe documents such as this should be made routinely available by EPA without anyone having to file a freedom on information act request.   

Documentation from test labs to show stoves meet certification requirements go to Rafael Sanchez at the EPA Office of Enforcement and Compliance at EPA's headquarters in Washington DC.  This memo came from a review done by Steffan Johnson, based in Research Triangle in North Carolina.  Mr. Johnson is the Group Leader for the Measurement Technology Group at EPA's Office of Air Quality Planning and Standards,  the Measurement Technology Group provides national leadership in furthering the science of characterizing and measuring air pollutant emissions from industrial sources and is the EPA's focal point for producing validated emissions test methodology.  The Group also provides expert technical assistance for EPA, State, and local enforcement officials and industrial representatives involved in emissions testing.

(March 2021 update: Alaska sought and received approval from the EPA for an IDC cordwood stove test method to be "broadly applicable" which means any manufacturer can choose to use it in a stove's certification test.  It was partially sought because of weaknesses in the ASTM cordwood method and it also sets the stage for Alaska to potentially require that test for stoves sold in Fairbanks.)

From: "Johnson, Steffan", EPA
Date: 6/13/19 4:18 pm

To: all EPA Approved Wood Heater Test Laboratories and Third Party Certifiers,

In reviewing some recent test reports that have been submitted to EPA with the intent to certify a wood heater to the Subpart AAA cordwood emissions standard, there are some discrepancies and concerns that we are observing, and we will be asking some manufacturers to revise and resubmit a corrected compliance test report.  At least one of these concerns (noted below) is critical and may require re-testing.  All of these items are important enough to request a corrected report, and we wanted to let all of you know just why you may be contacted by your client(s) with such a request.

1. We have seen a number of test reports using the Alternate Test Method and ASTM E-3025 that do not identify the species of cordwood used for the com pliance testing.  While it is true that the ASTM method allows selection from a wide list of wood species, the test report must identify the species of fuel used.  This is specified not in the test method but in the General Provisions to EPA 40, Part 60.8 (f)(2) which governs content that must be included in the test report. Paragraph (iii) of this section reads:  “(iii) Description of the emission unit tested including fuel burned, control devices, and vent characteristics; the appropriate source classification code (SCC); the permitted maximum process rate (where applicable); and the sampling location.”

We are asking that test reports that did not identify the wood fuel species burned during a compliance test submit an amended test report to this Agency.  If you are a third party reviewer and have certified such a test report, we request that you include this item, along with other items listed in the General Provisions, in your review checklist. 

2. We have seen some test reports that reference “manufacturer’s instructions” for conducting the certification test, yet those instructions were not included in the test report.  The requirement to submit this information is to comply with the General Provisions of 60.8(b) and (c).  The guiding principle here is that ONLY the EPA Administrator has the ability to modify a test method for any reason, and these manufacturers instructions do NOT supersede the test method.  Also, the National Stack Test Guidance Document (available here:  https://www.epa.gov/compliance/clean-air-act-national-stack-testing-guidance) clearly states that the emissions test report “must demonstrate all information from the test lab such that it is a stand-alone document capable of reproducing the entirety of the test results”.  As such, all information pertinent to the operation of the appliance during the testing must be included in the test report (per 40 CFR 60.534). Also, as such instructions are relevant to how the testing was conducted, this documentation is not Confidential Business Information (CBI). 

We are asking manufacturers that have issued test reports where the manufacturers provided instructions to the test lab regarding appliance operation during the test, and that documentation was NOT included in the emissions test report available to the public, to take corrective action and submit an amended test report to this Agency.  If you are a third party reviewer and have certified such a test report, we request that you now include this item, along with other items listed in the General Provisions, in your review checklist.

3. We have seen some test reports that contain manufacturer’s instructions that may run contrary to the test method and rule requirements.  Specifically, we have seen instances where manufacturers have directed laboratories to conduct low load testing with air inlet damper settings at “specified distances from fully closed”, meaning that the unit may not be getting tested at the lowest operating rate that a homeowner will have access to during the course of normal daily operation.  Testing at the lowest setting a consumer will be able to operate the appliance in their home is specifically required in 40 CFR 60.534.

Test labs and third party certifiers who are conducting /observing testing where manufacturers provided such instructions AND where you have knowledge that such devices are capable of combustion with air inlet dampers more fully closed than those setpoints specified by the manufacturer review the rule requirements with their client(s) and either select the lowest available setpoint or modify that stove model to fix the lowest available air inflow setting at that specified point, to remain fixed thereafter.  Furthermore, we insist that laboratories and third party certifiers add the requirement(s) of 60.534 to their checklists and take necessary steps to not look past this requirement in the future.  Appliance models found to have been tested in this manner and subsequently certified, will need to be reviewed by EPA on a case-by-case basis.  As a reminder, third-party certification is an attestation that all testing was conducted as specified in the regulation; certification of testing that does not meet the regulatory requirements may result in loss of EPA Approval status.  

4. We have seen some test reports where cordwood fuel is used to demonstrate compliance, and the dimensions of the “cordwood” very closely match the dimensions of crib fuel.  While we recognize that it may happen that occasionally a wood splitter would produce a piece where the minor cross section is nearly equal to the major cross section of the fuel piece, we expect that this happens infrequently and is not normal for every piece in a fuel load. 

We ask that labs and third party certifiers use pieces that approximate hand-split fuel and not something that seems to be far more selective.  While fuel pieces are ‘selected’ for the test based on size and weight and, to some extent, dimension, we expect to see fuel loads that are more random (in terms of piece-to-piece comparisons) than not.

As always, thank you for continuing to support the EPA Wood Burning Appliance Certification Program.  Please do not hesitate to reach out to us and ask questions, any time, with respect to any certification testing you are undertaking; we are happy to offer our technical direction to help you, and your clients, meet the subpart AAA and QQQQ regulatory requirements.

My best regards,

Stef Johnson

Steffan M Johnson | Leader – Measurement Technology Group | US EPA Office of Air Quality Planning and Standards | Air Quality Assessment Division | 109 T.W. Alexander Drive, RTP, NC  27710 | Mail Drop: E-143-02 | Phone: (919) 541-4790  | Cell: (919) 698-5096

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HPBA lawsuit extended again in hopes of renewed talks with EPA

The US Court of Appeals for the DC Circuit agreed to yet another extension to the lawsuit brought by the Hearth Patio & Barbecue Association (HPBA) and the Pellet Fuel Institute (PFI) against portions of the EPA’s 2015 residential wood heater regulations.

HPBA “hopes to be back in talks with the EPA” said Rachel Feinstein, Government Affairs Manager for HPBA. In the motion requesting the extension, HPBA explained that talks between them and HPBA had broken down under the Obama Administration, but after Trump's election, HPBA is again “attempting to discuss with DOJ and EPA whether the agencies are willing to engage in further discussions concerning the Rule.”

The Trump Administration has been re-opening rule making on many regulations, but some observers say it will likely be an uphill battle for the hearth industry because the EPA is already contending with many higher profile rules. In addition, even if the EPA were to agree to review parts of the NSPS, the rule would have to go through the notice and comment process that can take 1 to 3 years, at which point there could be a new President and a new head of the EPA.

The EPA can revise regulations at any point, with or without a pending lawsuit. It can commit to a new rule making process on selected parts of the NSPS, but it cannot necessarily guarantee any particular outcome. In cases of voluntary remand, petitioners can also lose their right to appeal.

If the case goes to court in 2018, the outcome partially depends on which panel of judges get appointed to the case and the result could be more unpredictable and potentially more favorable to the groups that intervened in the suit – the American Lung Association, the Clean Air Council and Environment and Human Health. If the case goes to court, the best outcome for HPBA would likely be a settlement agreement that puts part of the NSPS on hold until another rule making is complete.

HPBA and PFI now have until August 25 to file their brief laying out their grievances with the new regulations. HPBA is not challenging the requirement that when tested with cribwood, wood stoves must emit no more than 2 grams an hour as of 2020. This means that all stove manufacturers remain under this deadline to retest their stoves to achieve 2 grams an hour or less under the revised test method. All stoves that tested at 2 or under prior to May 15, 2015 still have to retest to be compliant with the 2020 limits. 

HPBA is challenging the requirement that if a stove is voluntarily tested with cordwood, it must achieve 2.5 grams per hour or less. HPBA asserts that since there is not yet an approved test method, it was premature for the EPA to set an emission limit. HPBA is also challenging emission limits for wood and pellet boilers and furnaces.

Related posts:

What consumers need to know about the new EPA wood stove rules. (Updated, June 2017)
HPBA gets delay in lawsuit to give Trump administration time to review.  (April 2017)
Paper undermines stove industry variability study. (August 2014)

A Response to James Houck’s Indictment of the NSPS

A stove being tested at
Omni lab, where Jim
Houck used to work.

In the May issue of Hearth & Home magazine, James Houck wrote a lengthy criticism of the 1988 and 2015 NSPS,  Straight Talk”, in which he took the “gloves off ... to tell it like it is.” It is essential reading for anyone who wants to better understand the science and politics of regulating wood stoves.

But let’s take this a bit further and examine some of things that Jim Houck did not mention that also have implications for the future of wood heating in America. Houck states his premise is right up front:

“The 1988 NSPS was bad.  The 2015 NSPS is bad.  They are bad technically and they are bad for the hearth industry.  Certainly they have and will provide some environmental and health benefits, but they are poorly written, they have loopholes, they have cost the hearth industry dearly [and] they have allowed gamesmanship. [...] The blame cannot be put on regulators alone: those in the hearth industry also share some of it.”

Jim goes on to explain why we are going down the wrong path.  The 2015 NSPS essentially adopts the same test method as the 1988 one: a method based on grams per unit of time, not grams per unit of fuel, or better yet, grams per unit of heat.  He also very clearly shows how both the EPA and industry have ignored basic science by, for example, claiming that certified stoves reduce pollution far more than the data shows.  The best data shows an average decline in PM of nearly 50%, yet the EPA often claims its 75% and industry 90%.

The key question is, can manufacturers make genuinely cleaner stoves regardless of the EPA regulations?  Put another way, do manufacturers have the expertise and innovation necessary to take stoves to the next level despite poor regulations, or does the NSPS retard innovation and require that stoves continue to be designed according to faulty parameters?  There are good arguments on both sides of this debate. 

 

The lead author of the 2015 NSPS
was Gil Wood, at right, who retired
the day the final rule was published.

Two of the greatest threats to stoves burning clean in homes are things that Houck never mentioned: tuning primary air for cribwood, not cordwood, and the EPA requirement that stoves burn at a low burn rate.  Together, those requirements almost guarantee that cordwood stoves in homes are likely to produce smoke at their lowest burn rate.

Jim Houck does not mention the upcoming switch to cordwood testing laid out in the newest NSPS.  Nor does he mention that the cordwood test method will include a cold start.  Granted, emissions will still be measured in grams per hour and the process of getting to cordwood testing is fraught with scientific, political and legal potholes.  But industry, the EPA and other key stakeholders at least see the need and value of getting there.

Houck’s article is about non-catalytic stoves.  The testing, repeatability and other issues can be very different with catalytic and pellet stoves.  Together, pellet and catalytic stoves make up one third or more of stove sales.  It should not be anathema to recognize that other technologies can achieve greater repeatability in the lab and greater consistency between the lab and the living room.  Otherwise, it makes it sound that all biomass heaters are far dirtier in the homes than in labs which is not true with pellet stoves and boilers. If consistency is the goal, we need to focus on technologies which can do that best, including automated stoves that use sensors to regulate primary and secondary air.  Homeowners can never keep track of changing combustion conditions like an oxygen sensor can.

 

Automated stoves that help
ensure the stove gets enough air
during key parts of the burn
cycle can greatly reduce PM in
in real world use.

It’s also worthwhile looking at regulatory frameworks in other countries to see if better stoves emerge where they test using grams per unit of heat and avoid other pitfalls of our NSPS.  Looking at non-cat wood stoves produced by various European countries, New Zealand and elsewhere, I think we can pretty safely say that our non-cat stoves measure up very well, if not better than stoves from those countries.  Part of the answer is because regulations in those countries allow for a different set of loopholes and types of gamesmanship. 

The bottom line is that it appears that despite all the failings of the NSPS, it still may be one of the best regulatory systems anywhere for conventional wood stoves.  Europeans have advanced wood and pellet boiler technology faster than the US because higher heating fuel prices and policies promoting renewable energy have led to a greater demand for efficient technology. 

Houck says that the 1988 NSPS was bad and notes that hundreds of companies went out of business because of it.  But it did result in a new generation of cleaner stoves that appear to be about 50% cleaner.  Houck recalled that we are now saddled with the legacy of the 1988 test method thanks to one stubborn regulator who strongly advocated it and subsequent bureaucratic inertia.  Making radical changes to the NSPS is difficult for the EPA, due in part to its lack of resources—a condition which is likely to get worse under the current administration.  In fact, the lack of resources at the EPA could hobble the stove industry even more than the new regulations.  As it is now, there is only one official who does enforcement, which includes approving lab certifications.  If that person’s time were to be cut back even more, it could pose serious economic consequences for manufacturers trying to get stoves to market for the heating season.

In 1988, the EPA almost adopted a test method using the Condar, a very small portable dilution tunnel that uses larger filters.  Some data from the Masonry Heater Association shows that by simply using a larger filter to catch PM, the repeatability of testing can be significantly improved (powerpoint).  But any radical change to test methods would likely have to come from a transparent process driven by an institution that has the funding and credibility to carry it out.  

Extensive round robin testing in Europe
 coordinated by BeReal should expand our
understanding of repeatability.

Universities or labs could develop of a better test method, but stoves do not have the same level of R&D support from Congress, DOE or other potential major funders that other renewables have. In Europe, there is more public funding and the BeReal project is doing far more extensive round robin testing than what Houck describes in the US.  Some agencies and groups prefer to see stove technology stagnate and have its market share wither, due to antipathy or ambivalence toward this complicated creature that can be affordable to homeowners but too often noxious to neighbors.

We will never know what would have happened if the regulators had written better test methods.  Perhaps todays’ stoves would reduce PM by 60 or 70%, instead of the 50% that Houck cites.  We also don’t know how much better stoves will be 10 years from now after the 2015 NSPS plays out.  It appears that few stove manufacturers will go out of business this time around, partially because many of them also rely on profits from their gas stove lines.  But will the stoves really be cleaner in the hands of average homeowners?

Ben Myren, owner of one of the EPA
approved test labs, is a leader in
developing cord wood testing.  Here
he starts a cord wood test at the 2013
Wood Stove Design Challenge.

The NSPS is supposed to be updated every 8 years, so theoretically there will be regular opportunities to improve the testing process.  If we can get to cordwood testing in the next 5 years, possibly the next NSPS could move to testing grams per unit of heat.  Litigation over this NSPS may bring some relief to some boiler and furnace manufacturers and others, but it may have the opposite impact on support for wood heating among civil society in general. 

Attitudes of the general public that shape policies at all levels of government, our media, the non-profit sector, etc., will have to change if wood heating is really going to be a growing renewable energy technology.  We have hosted the Wood Stove Design Challenge, with the next one scheduled for November 2018, to see if we can focus attention and resources on genuine technological advances that make stoves cleaner in homes.  Public opinion will only change when stove technology changes and stoves become cleaner not just in the lab, but also in our communities.  The 2015 NSPS alone will not get us there, for all the reasons Jim Houck outlined, but it is still possible to get there.

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A response from Scott Nichols on boiler repeatability

Scott Nichols, owner of Tarm Biomass that distributes European made boilers sent in a response to this blog and we reproduced it below.  Scott is also on the Board of Advisors of the Alliance for Green Heat.

I agree with a great deal of what Dr. Houck wrote.  The single biggest problem with emissions from wood burning is that old stock remains in the market.  

Inherent test variability for appliances designed to burn firewood is also a problem without a doubt.

Scott Nichols has been a leader in
installing modern, automated boilers
in institutions and homes in New England.

Of course, my world is now the boiler world and the some of the testing used for boilers solves several of the problems inherent with wood stove testing.  I’ll mention some of the differences, as It may spur some ideas as you think about testing for woodstoves.  

For instance:

1)      The partial thermal storage test method is a cold to cold test, which is more indicative of both worst case and standard conditions.

2)      Boiler PM is reported in lbs/MM Btu, which eliminates the appliance size conundrum that Dr. Houck mentions at length. 

Further:

1)      Boilers very often include lambda technology, which enables the boiler to react to real time stack conditions by adjusting combustion air to optimize combustion.  Lambda technology improves cleanliness by helping the appliance to accommodate various wood moistures, volatility of the fuel, size and shape of the fuel, draft, and other factors in real time.

2)      Some regulators are already thinking about how to encourage lambda technology because they know that outside of the lab, such technology can more closely provide results as tested in laboratories.

3)      Boilers are built much more robustly than stoves and usually do not use catalysts that deteriorate over time.  They therefore tend to produce as tested results for a longer period of time. 

4)      Thermal storage allows for what is effectively single burn rate operation.  In a laboratory that can result in 4 test runs in which the boiler operates identically from run to run at full output.  This enables more comparable data for each test even though each run is weighted differently.  

5)      Round robin lab testing of one of our boilers has been underway for months.  That testing has been funded by NYSERDA.  We don’t know the final results yet, but it is important to note that people are thinking about repeatability and are putting money behind learning more.  Initial results, before we were removed from the viewing process, indicated that repeatability was a problem. 

Problems with wood boiler testing that wood stoves don’t have:

1)      Boilers are tested in room temperature laboratories.  Outdoor boilers are therefore provided an efficiency advantage because jacket heat losses in the laboratory do not reflect the real world. 

2)      Wood fuel used in outdoor boilers is always the temperature of the outdoors in the real world, not room temperature.  If you put 150 pounds of wood in a boiler and it is 10 F outside, combustion will be substantially different than if that wood is 60 F warmer in a laboratory.