RMH The Rocket Masonry Heater

Hi all;  
It all started when I wanted to get an idea of what the masonry stove regulations are in Montana.
Quite the rabbit hole, I am sure the little girl I passed on the way was named Alice...
The following are copied from the International Residential Code for one and two-family dwellings.

(c) a masonry heater constructed or installed in compliance with the requirements for masonry heaters in the International Residential Code of One- and Two-Family Dwellings

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.
Chapter 10 of the IRC
ASTM E1602 Standard for Solid Fuel Masonry Heaters
SECTIONR1002
MASONRY HEATERS
R1002.1Definition.
A masonry heater is a heating appliance constructed of concrete or solid masonry, hereinafter referred to as masonry, that is designed to absorb and store heat from a solid-fuel fire built in the firebox by routing the exhaust gases through internal heat exchange channels in which the flow path downstream of the firebox includes flow in a horizontal or downward direction before entering the chimney and that delivers heat by radiation from the masonry surface of the heater.

A full copy of this information can be purchased or viewed online.

My take on what I read, is that Montana allows home-built masonry stoves  (Rocket Masonry Heater) :-) as long as they follow the international building code.
I would talk with the insurance company to confirm they will cover your home.
One document I read said masonry stoves are exempt from needing a UL rating as they are generally only lit two times per day.
Each case and each insurance company may have different standards.
However, I am encouraged that it may be a legally insurable build by following the IBC codes.

Yep, first off, call it a masonry heater and not a rocket anything

The major issue you may run into depending on the jurisdiction is whether it is required to be built or supervised by a licensed/certified/whatever professional.
Another point is that the code specifically requires refractory mortar and forbids clay-sand mortar. You may need to follow that depending on your local circumstances.

A few years ago I actually bought a copy of ASTM E1602 (something like $60 for 9 pages of content) since I couldn't find its complete text online, and it was pretty much exactly the same as the IRC text, with very little additional information. It has several examples of designs in schematic form, all of them contraflow and none using stratification chambers or bells.

This was pretty much my experience, with Ohio code being the same.  Don't say rocket unless you want to frighten someone.  Especially your code guy or insurance agent.

Fortunately, we live in a very rural county that has no building code or building inspectors. We just need to comply with state electrical and plumbing codes. So no issues here with the Man meddling in my business. However, the insurance question is certainly one to be considered. My assumption is that if you have an insurance claim for anything related to fire or combustion gases, as long as it is clearly shown that the "masonry" heater wasn't the cause of the issue then there should be no issue with insurance. Perhaps this is a question that needs to be carefully crafted for your insurance person so that you don't get an answer that you really don't want to hear and risk having your insurance cancelled. I'm curious to hear if anyone has experience with this discussion with their insurance company.

The big issue that I have seen in looking at some of the online posts of peoples builds are questionable practices primarily with regard to RMH placement and proximity of combustible surfaces without proper heat shielding or questionable venting of exhaust gases.