Masonry Heaters and the NSPS

By Norbert Senf,
Chair of Masonry Heater Association Technical Committee,

and member of the Board of Advisors of the Alliance for Green Heat

EPA has released the long awaited new version of their “New Source Performance Standard”, which now includes masonry heaters in the section “RRRR”.  In the last edition of this Standard, released in 1988, masonry heaters were exempted as “inherently clean burning”.

Norbert Senf lives in Quebec
and has built masonry heaters
for more than 30 years.

The Masonry Heater Association (MHA) technical committee has worked very hard to produce written comments and recommendations to the Proposed Standard (P.S.).

The draft NSPS proposes an emissions limit of 0.32 lb/MMBtu for particulates for masonry heaters. HPBA is opposed to a lb/MMBtu limit, and is advocating for g/kg. In g/kg terms, that would be about 1.8 g/kg, assuming 70% efficiency. HPBA cites the fact that lb/MMBtu requires an efficiency number, and that there is no EPA recognized efficiency test method for masonry heaters.

The MHA tech committee feels that lb/MMBtu will eventually be a better way to compare heating appliances, since it takes efficiency into account and avoids having to make the distinction between g/kg for heat storing appliances and g/hr for continuous burn stoves. To that end, MHA is conducting testing to see if the CSA B-415 efficiency method can be adapted to masonry heaters. However at this point we will support the HPBA position.

Two tech committee members are currently conducting testing on the Austrian Eco- firebox air design, which was presented at the MHA annual meeting in 2013. We are measuring repeatable particulate (PM) numbers substantially below 1 g/kg, roughly a 50% reduction from existing designs. More information on the testing can be found here.

The fueling method proposed is ASTM E2817, which defaults to "manufacturer’s instructions", the method used in Europe. There are annexes for alternative crib and cordwood fueling methods. In-house testing at MHA is showing good repeatability with "manufacturer’s instructions" and cribs. Crib emissions appear to be roughly 50% higher than "manufacturer’s instructions" with cordwood.

Perhaps the biggest challenges presented by the practical aspects of the proposed standards lie with the fact that EPA doesn’t understand the unique operating characteristics of the masonry heater industry. For lack of adequate funding in addressing this tiny portion of the wood burning industry, regulators ended up copying much of the language from “AAA”, the wood stove portion of the P.S. 

For example, the P.S. refers to masonry heater Certified Model Lines, and includes a Licensing Restriction and a Storage Requirement.  The “model line” issue would require every heater built to be tested for emissions at an EPA certified lab.  The “licensing” restriction prevents MHA from certifying a heater and selling the plans for it.  The storage requirement would require a heater builder to keep a copy of every different heater built in a sealed container.  MHA is protesting all of these issues as unacceptable, since masonry heaters are typically very heavy, site built one-of appliances - similar to a masonry fireplace, except with dramatic performance improvements. Many heater masons have met the substantial requirements of the MHA Heater Mason Certification Program, and discussions need to take place with EPA on more feasible regulation compliance mechanisms for masonry heaters.

On a more hopeful note, as an alternative to certification testing, RRRR would permit a “validated computer model simulation program”.   A limited version of this is already used in Europe. It could provide a good way to certify a “family of units” defined as units with the same firebox dimensions and also gain acceptance of “substantially similar” heaters.  The technical committee has a project under way to design and verify a calculator to meet compliance under this clause.  This could be a key way to continue to offer custom designs to clients.

 Anyone building fewer than 15 masonry heaters per year would be granted a 5-year extension for compliance with the emissions limit.  It is a delay of standards that will be imposed for larger manufacturers when NSPS becomes law, likely in 2015.

  

(The views expressed here do not necessarily reflect the views of the Alliance for Green Heat. We have asked Norbert Senf and others to assist the Alliance in developing our comments to the EPA on masonry heaters.)