20 yrs ago we lost two nieces to a house fire, due to negligence on the baby sitters part. She sat something on the stove that caught fire. The Detroit firefighters were amazing the way they supported our family through this time. It was this experience that lead me to join our local volunteer fire dept and do more to serve my community.. It was also the reason I have tried to provide info on how to reduce clearances using Thermodynamics to move the heat away from the wall cavity.
There are lots of pictures on brochure of stoves that have installed in a manner that counterdicts the specs on the stove, there are also stoves that require so much clearance they would stick out in the room too far. It is these experiences that has caused me the greatest concerns as some folks do not understand the dynamics of spontaneous combustion.
What I see more than anything is masonry installed with no air space, over a wood framed wall. This is far worse than just leaving the drywall exposed as the masonry will absorb the heat and hold it against the wall far longer than if it was exposed and could cool down faster. This heat is then trapped and transfers into the wall gravity where it will dry out the internals of the wall. If there is wood in the wall, once the moisture content in the wood drys to zero and the temperatures rise above high enough, the wall can achieve combustion from the inside, without your knowledge that there is even a problem. Worse yet is an old home with plaster over wood lath walls which are already old and dried out. They will burn faster and allow the occupants less time to know there is a problem.
It only takes 3 things make fire, heat, fuel and oxygen. Deny any one of those and you will not have combustion. In most cases there is not enough air in a wall cavity to complete combustion, but drill a few extra holes ruining power or other wires, and you have what it takes to have a fire.
We have made some You Tubes on different ways to reduce clearances to combustibles, we show you how to prep the wall to achieve a 67% reduction according to approved NFPA formulas, using materials that can be found locally in most places. We even began making custom heat shields for some of the cookstove's we offer, to make them easier to install.
http://www.youtube.com/user/WoodyChain/videos?query=reducing+clearances+to+combustibles
A proper way to build a heat shield is one that has air space and will convect fresh cool air from the floor area and carry the heat up and out the top. The key is the air space between the combustible wall and whatever type heat shield your using. You can even use a combination of ways to reduce clearances more than 67%. Here is a look at what I have done,
http://www.youtube.com/user/WoodyChain/videos?query=heat+shields
I hope this helps anyone trying to reduce their clearances. As always, not sure, just call me, I'll try to help as much as I can.