I am a firefighter, but not really sure of fire codes. They very from county to county, as well as state to state. I burn firewood in my home, and I use a double wall stainless chimney. This is a double wall chimney with insulation between the walls. It is quite pricey, but you can put your hand on it without burning it. I've never been on a fire call for a chimney fire with this kind of application. Where the chimney exits the wall on my house there is only 3" of clearance between the chimney and OSB. Been burning this way for 10 years no problem, and the chimney is a good as when I put it up.