by Norbert Senf,
Chair of the Masonry Heater Association Technical Committee
Left to right: Mark Champion (in his
VT test lab), Boris Kukolj (Tulikivi),
Chris Prior (MHA President), Norbert
Senf (blog author) and Jean Francois
Vachon (soapstone supplier).
Photo credit: Mark Seymour.
EPA started regulating wood burning stoves for particulate (PM) emissions in 1988. Regulation was limited to airtight heating stoves. Masonry heaters were not regulated, the stated reason being that they were likely to be clean burning.
In Europe, only carbon monoxide (CO) emissions were regulated. CO is easy to measure, however PM can be very tricky. Wood smoke includes
compounds that will only be captured by a filter if you cool them down and condense them. This is done in the laboratory by mixing them with air in a dilution tunnel, and this is thought to simulate what happens in the ambient air in the real world.
State and county air quality authorities soon started to address wood smoke, and would often pass a generic local regulation that banned all appliances except those that were EPA certified. We, the fledgling Masonry Heater Association (MHA), decided to seek EPA certification.
Although we “knew” that masonry heaters were cleaner even than EPA stoves, nobody had ever measured the PM on one with the dilution tunnel method. With funding help from the Wood Heating Alliance (now HPBA), we were able to participate in a $ 100,000.00 test method development project for masonry fireplaces and masonry heaters. The project took place at Virginia Polytechnic Institute (VPI) in 1989 and was headed by Dr. Dennis Jaasma.
The results were interesting, with some surprises. EPA did not accept the proposed test method. We immediately realized that we needed do a lot more testing,
and that we would need to develop the capability to do it ourselves.
We were fortunate in being able to arrange for training with OMNI-Test, one of the leading EPA-accredited certification testing laboratories, then and now. OMNI developed a training session for us that took place in September 1996. It included presentations by regulators, an emission chemistry expert (Dr. Jim Houck), and laboratory testing personnel. Dr. Stockton (Skip) Barnett showed us the low cost portable dilution tunnel that he invented, known as the Condar. He developed it while working for the Condar Company. It was widely used at the time by the major stove manufacturers for in-house testing to develop their certified stoves.
The attached Powerpoint
, Repeatability of Cordwood Combustion Particulate Measurements,
presents a summary of the work we have done at the Masonry Heater Association
to calibrate the Condar against the EPA Method 5G laboratory dilution tunnel. It includes a close look at the PM testing repeatability issues,
a major discussion point over the years. We have recently completed 2 cordwood studies, using very carefully matched loads in a masonry heater. Repeatability was within plus or minus 15% – 25%, depending on the ignition method. With crib fueling, we were able to get within 10% repeatability on PM, and within 1.5% repeatability on CO.
Posted by Earth Stove on April 11, 2014 with No Comments
By Norbert Senf,
Chair of Masonry Heater Affiliation Specialized Committee,
and member of the Board of Advisors of the Alliance for Inexperienced Heat
EPA has unveiled the prolonged awaited new model of their “New Resource Overall performance Standard”, which now contains masonry heaters in the segment “RRRR”.  In the very last version of this Standard, introduced in 1988, masonry heaters were exempted as “inherently clear burning”.
|Norbert Senf lives in Quebec
and has developed masonry heaters
for far more than 30 years.
The Masonry Heater Affiliation (MHA) technological committee has worked very difficult to generate written remarks and recommendations to the Proposed Common (P.S.).
The draft NSPS proposes an emissions limit of .32 lb/MMBtu for particulates for masonry heaters. HPBA is opposed to a lb/MMBtu restrict, and is advocating for g/kg. In g/kg terms, that would be about 1.eight g/kg, assuming 70% performance. HPBA cites the fact that lb/MMBtu requires an efficiency variety, and that there is no EPA recognized performance take a look at strategy for masonry heaters.
The MHA tech committee feels that lb/MMBtu will at some point be a greater way to evaluate heating appliances, since it requires effectiveness into account and avoids getting to make the distinction among g/kg for warmth storing appliances and g/hr for steady burn up stoves. To that end, MHA is conducting tests to see if the CSA B-415 efficiency strategy can be adapted to masonry heaters. However at this point we will assist the HPBA position.
Two tech committee customers are at the moment conducting tests on the Austrian Eco- firebox air layout, which was introduced at the MHA yearly conference in 2013. We are measuring repeatable particulate (PM) numbers substantially below 1 g/kg, around a fifty% reduction from current types. Much more information on the screening can be discovered here
The fueling strategy proposed is ASTM E2817, which defaults to “manufacturer’s guidelines”, the method utilised in Europe. There are annexes for option crib and cordwood fueling techniques. In-home testing at MHA is displaying good repeatability with “manufacturer’s instructions” and cribs. Crib emissions seem to be approximately fifty% larger than “manufacturer’s instructions” with cordwood.
Maybe the greatest problems introduced by the functional aspects of the proposed requirements lie with the simple fact that EPA doesn’t comprehend the special running qualities of the masonry heater business. For lack of adequate funding in addressing this tiny portion of the wood burning business, regulators finished up copying significantly of the language from “AAA”, the wood stove part of the P.S.
For example, the P.S. refers to masonry heater Licensed Model Traces, and involves aLicensing Restriction and a Storage Prerequisite.  The “model line” issue would need each and every heater built to be examined for emissions at an EPA qualified lab.  The “licensing” restriction helps prevent MHA from certifying a heater and promoting the ideas for it.  The storage necessity would demand a heater builder to hold a copy of every single distinct heater built in a sealed container.  MHA is protesting all of these concerns as unacceptable, given that masonry heaters are typically really weighty, website constructed 1-of appliances – similar to a masonry hearth, except with spectacular functionality enhancements. A lot of heater masons have fulfilled the considerable needs of the MHA Heater Mason Certification Program, and discussions need to have to consider spot with EPA on a lot more feasible regulation compliance mechanisms for masonry heaters.
On a a lot more hopeful note, as an substitute to certification screening, RRRR would permit a “validated personal computer product simulation program”.   A constrained edition of this is presently utilised in Europe. It could offer a excellent way to certify a “family of units” outlined as units with the same firebox proportions and also obtain acceptance of “substantially similar” heaters.  The complex committee has a undertaking beneath way to style and validate a calculator to fulfill compliance below this clause.  This could be a important way to keep on to supply customized designs to clientele.
Anyone developing fewer than fifteen masonry heaters for each year would be granted a five-year extension for compliance with the emissions restrict.  It is a delay of specifications that will be imposed for greater companies when NSPS becomes legislation, most likely in 2015.
(The views expressed below do not always reflect the views of the Alliance for Green Heat. We have asked Norbert Senf and other individuals to support the Alliance in establishing our feedback to the EPA on masonry heaters.)