Custom masonry heaters are fully permitable in the United States thanks to their inclusion in the US Building Codes and their acceptance by the EPA.
US Masonry Heater Building Codes
Masonry Heater construction is addressed in section R1002 of Chapter 10 of the IRC, entitled “Chimneys and Fireplaces”:
R1002.2 Installation. Masonry heaters shall be installed in accordance with this section and comply with one of the following:
1. Masonry heaters shall comply with the requirements of ASTM E 1602; or
2. Masonry heaters shall be listed and labeled in accordance with UL1482 and installed in accordance with the manufacturer’s installation instructions.
What this means basically is that manufactured masonry heaters should have a UL listing while custom masonry heaters should follow the guidelines set forth in the ASTM E1602 standard. This pass-through reference means that the majority of the code referring to custom masonry heaters is in the ASTM standard.
The rest of the section on masonry heaters is brief but does lay out important prescriptions for seismic reinforcing and minimum clearance to combustibles. A full article to better understand the prescriptions offered for masonry heater foundations is available here.
ASTM E1602 Standard for Solid Fuel Masonry Heaters
The ASTM E1602 Standard for Solid Fuel Burning Masonry Heaters is the defining document for best and safe masonry heater construction practices. Any architect, builder, or building official involved in masonry heater design and construction should own a copy of this document.
The ASTM Standard defines a masonry heater and addresses basic masonry heater designs, acceptable materials used, further specifies clearances to combustibles, hearth extension requirements, outside air requirements, cleanouts and wing walls. We hope to provide additional detailed articles describing each of these items in the future and make sure to join our mailing list to receive updates.
EPA & Emissions Regulation
Masonry heaters do not currently require EPA certification. This determination was reinforced by the current New Source Performance Standard (NSPS) released by the EPA where it recognized the inherent clean-burning nature of masonry heaters and also to give time for the industry to futher develop testing standards.
Building Code in Canada
We are currently doing research on this and also invite guest authors on the topic.
History
We are very lucky that a dedicated group of masonry heater enthusiasts and professionals joined together during the 1980s to get clear references to masonry heaters into the building codes and developed the ASTM Standard for custom masonry heater construction. This effort was one of the galvanizing forces for the creation of the Masonry Heater Association of North America. For the time being, there is a very clear pathway for individuals to apply for and receive permits for custom masonry heaters through their local building departments.
The future of regulation with regards to emissions is a little less certain. As powerful residential heating appliances, masonry heaters are unique in that they are site-built by disperse expert artisans rather than centrally manufactured. Furthermore, it has proven difficult to compare masonry heater emissions directly to wood stoves with a g/hr rate because the heat generated by a masonry heater in a couple of hours of combustion is stored and continues to radiate into the next day. For now, the EPA has held off on requiring certification of custom masonry heaters.
Design Recommendations
References
- US Masonry Heater Building Codes
- The EPA and Emissions Regulations
Hi There. Currently interested in this topic. Let me remark other three standards on the topic:
ASTM E2778 Standard Specification for Custom Tiled/Mortared Masonry Heaters (Stoves)
ASTM E2817 Standard Test Method for Test Fueling Masonry Heaters
CAN/CSA B415.1 Performance Testing Of Solid-Fuel-Burning Stoves, Inserts, and Low_Burn-Rate Factory-Built Fireplaces
Saludos.
@PabloK, it is an honor to have your presence in the forums! For those that don’t know of @PabloK 's work, he is very active in both heater construction and education in Argentina. I came to know of his work through his Instagram account:
Thank you for listing these relevant ASTM standards. The ASTM E1602 Standard Guide for Construction of Solid Fuel Burning Masonry Heaters has been the most relevant and the one I am most familiar with since it is specifically referenced in the building code. As a professional heater builder, it has been worthwhile to have a copy and be able to reference it when any questions came up with local building officials. I would like to write a follow-up article summarizing its most important specifications.
I had no idea about the “ASTM E2778 Standard Specification for Custom Tiled/Mortared Masonry Heaters (Stoves)”. My guess is that it was put together by a contingent of heater builders that were part of AMHOP, a now apparently defunct association of heater builders that had split off of the Masonry Heater Association (MHA). Does anyone on this list have any familiarity with the contents of this standard? Is it worth purchasing?
@mheat (Norbert Senf), is an authority on the final two you cited which have more to do with efficiency testing:
I should say also that I published the article that started the thread rather hastily in order to start this thread and that I look forward to improving it. Discussion here will certainly lead to its improvement.