Thursday, October 22, 2020

Alaska building list of properly certified wood and pellet stoves

Lab certification test are designed to
burn as cleanly as possible and all
emission results must now be publicly
disclosed as of 2015.

Alaska Finds widespread deficiencies in EPA wood stove certification process 

Officials in Alaska are in the process of compiling lists of wood stoves and boilers that have met all the requirements of EPA certification and emit fewer particulates during the first hour of the test burn. Alaska regulations requires new wood heating appliances installed in the Fairbanks nonattainment area to meet additional regulatory requirements beyond obtaining a federal U.S. EPA certification. The regulations went into effect January 8, 2020 and Alaska has been working to implement those regulations since then.  The new regulatory requirements involve reviewing certification test reports for deficiencies and collected data regarding additional PM levels and then approve specific models of wood stoves and pellet stoves by updating their approved device list.

The Alaska Department of Environmental Conservation (ADEC) began this process as part of their efforts to address excess wood smoke pollution that contributed to Fairbanks becoming a non-attainment area.  The State’s Implementation Plan (SIP) to improve air quality began including measures years ago to crack down on dirtier wood burning appliances, such as outdoor wood boilers.

The current effort involves reviewing every stove’s certification paperwork to ensure that it includes all the elements that EPA regulations require, such as average CO, the manufacturer’s written instructions to the lab, firebox dimensions, efficiency calculations, burn rate calculations, raw data sheets, documentation of run anomalies, etc. etc. 


If you are not familiar with this brewing controversial initiative, you are not alone.  The first time most people outside a small group of manufacturers and regulators heard about this was a month ago, Sept. 18,  when a group of states weighed in on the litigation between HPBA and the EPA Their brief mentioned that the Alaska Department of Environmental Conservation was conducting a systematic review of wood-burning devices that have been certified to be compliant with EPA standards. The Department found that 59% of the certifications had inaccurate certification data, and that the EPA must have a way to check on manufacturers through audits. 

The start-up phase of a stove in the lab
should be consistent with how it is
described in the owner's manual.

The lists being developed by Alaska officials only pertain to what can and can’t be sold in the Fairbanks Nonattainment Area, a very small market.  But regulators, manufacturers and test labs we spoke to all say that this is having major repercussions.  For the EPA, it’s a wakeup call that they have not been sufficiently reviewing test lab reports before certifying stoves.  Test labs are under more scrutiny for various practices and are already  being asked by manufacturers to help ensure their tests come in under 6 grams during the first hour.  And scores of manufacturers are scurrying to provide additional information to Alaska and showing them the details that were in their test reports that Alaska officials missed.  


One of the main reasons that everyone is paying attention is that most of the people AGH spoke to agree that other states and change out programs could adopt the Alaska lists instead of using the full EPA list of certified heaters.  If more change-out programs, or even states adopt these stricter requirements, the efforts of a small city in Alaska will have greater national ramifications.  Some managers of change out programs that AGH spoke to say they interested to explore ways to identify cleaner cord wood stoves and are uncertain whether the EPA’s reduction from a de facto 4.5 to 2 grams an hour actually resulted in cleaner cord wood stoves. Incentive and change out programs often have adopted stricter efficiency and/or emission requirements and this may represent the next vehicle for those programs to guide how taxpayer dollars should best be used.


The last time state regulators made changes that went on to have national implications may have been in 1995 when Washington State adopted a 4.5 gram an hour state standard, when the EPA allowed up to 7.5 grams an hour.  The 4.5 gram an hour limit soon became a de facto national standard and 20 years later, HPBA insisted it was still the lowest that the EPA should go for the 2015 NSPS.  

Non-confidential portions of emission
test reports made the Alaska investigation
possible for the first time.

Aside from developing new lists of stoves that met all the requirements of the NSPS and emitted less than 6 grams for the first hour of all their certification test runs, Alaska is providing a wealth of information to the EPA, NESCAUM and others who are already in the process of developing a new federal reference test method for certifying wood stoves.  Some regulators the Alliance for Green Heat (AGH) spoke to now acknowledge that they see the current system as “broken” and that no one knew it was so broken.  On November 16, Alaska will be making its data public, showing which requirements in the stove certification process are most commonly ignored or overlooked and which ones are complied with.  


The data to be released on Nov. 16 includes a two-page data sheet on individual stoves, showing any deficiencies in their test lab reports.   Each manufacturer will have had up to 2 months to review their own sheets and provide corrections to ADEC prior to their public release.  The initial sheets prepared by ADEC have numerous mistakes according to several manufactures AGH spoke to and include many of the data points that ADEC initially said were not in their test report.  Test labs have been helping manufacturers find relevant data in their test reports, and ADEC will continue making corrections before and after Nov. 16.


It’s not yet clear if any test lab reports may be so deficient that the EPA could revoke their certification or require that the stove be tested again.  EPA officials are just beginning to grapple with how widespread the problems may be and what they can do moving forward to help fix problems that should have been in plain sight for so long. The EPA has identified and tried to correct some testing deficiencies in the past.  An AGH blog in July 2019 covered an EPA memo asking labs to correct lapses in reports on stoves tested with the ASTM E3053 test method.  This incident may have contributed to greater scrutiny by states including Alaska’s far more in-depth investigation.

An ADEC official taking
air quality readings on top
of a school.

The EPA certifies stoves based on the weighted average of the entire burn but requires labs to also report the amount of PM in the first hour.  Like efficiency, its data that must be collected and reported by the lab to the EPA, but there is no regulatory limit.  The Alaska initiative is making everyone ask whether the first hour of emissions may be an equally important indicator of a stoves cleanliness than the entire burn cycle.  


Currently, the way EPA approved test labs test stoves is by using the standard Method 28 or a variation of it. Lab technicians load stoves with an amount of wood based on the size of the firebox and let the fire go until all the wood is burned, which usually takes anywhere from 4 – 9 hours but can be longer.  During the last several hours of the burn, known as the “tail”, there is virtually no particulate matter being released, but those hours are still averaged into the overall calculation, with much be less than 2 grams an hour with cribs, or 2.5 grams an hour with cordwood. 


AGH reviewed scores of test reports and found that single PM reading from the first hour could be as high as 20 grams an hour and the average of all the first hour burns could be as high as 10 grams an hour, but it would be less than 2 grams when the cleaner parts of the burn and especially the tail end of the burn was included.  For Alaska, if any single run went over 6 grams, it was rejected.  Since start-up is the dirtiest part of the burn, identifying stoves that have cleaner start-up may help airsheds improve air quality.


Test labs that AGH spoke to noted that this will likely have the result of disqualifying a greater proportion of larger fireboxes.  The average firebox size is 2.2 cubic feet and an initial small sample of stoves with average first hour emissions over 6 grams was 3 grams an hour.  One test lab also said that this could disadvantage catalytic stoves that have no secondary combustion during start up prior to engaging the catalyst, which often occurs 20 – 30 minutes after lighting the fire.  Hybrid stoves, however, that use both air tubes and a catalyst are likely to have cleaner start-up, according to test labs.


Some manufacturers are angry that a state is using a brand-new emission metric – first hour emissions – that they could have designed for, if they knew it would be used in some markets to regulate stoves.  Now that it has been flagged, manufacturers certifying stoves going forward can try to meet that – or at least urge the lab to build  the type of start-up fire that will come in under 6 grams.  One of the primary goals of a lab is to familiarize themselves with the stove being tested so they can “optimize stove operations during certification testing.” Some regulators fear that this will just become another factor that manufacturers and labs will use to “game the system.”


The Alaska initiative will have a far greater impact on wood stoves than pellet stoves.  Extremely few pellet stoves emit more than 6 grams in their first hour and the testing regimen is more straightforward.  Ultimately, only a dozen or fewer pellet stoves may be disqualified by their review, out of the 98 models that are currently certified. Of the 144 currently certified wood stoves, up to a quarter to a third could be impacted.   New outdoor wood boilers are not allowed in Fairbanks already.  They will be reviewing pellet boilers for compliance.

An inversion in Fairbanks that traps
wood smoke close to the ground.,

Next steps


As of Nov. 16, Alaska will publish its review on virtually every EPA certified stoves.  On December 1, only those stoves that ADEC found had complete test reports will remain on the approved device list and be allowed to be sold in Fairbanks.  If a manufacturer needs more time to address potential report deficiencies, they can contact ADEC and if they commit to working to correct the deficiencies, their device may remain on the approved device list.  The first hour emission of 6 grams on each test run requirement, went into effect on September 1, 2020, and those devices have already been removed from the approved device list. 


Other jurisdictions, incentive and change-out programs will likely begin assessing whether the Alaska list represents better stoves for public funding.  Consumers who really care about a cleaner stove could also check that list before buying a stove.  For now, there are more questions than answers but the bottom line for everyone in the industry and the wider renewable heating community is that this is a story to watch.

Related stories

Veteran lab technician challenges Alaska's wood stove criteria (March 2021)

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