Where do fire and pest resistance fit in?

Building science question, and of course I'm interested in how this applies to materials and methods that fall under the "natural building" umbrella, though I'm also curious about how you'd approach this in conventional construction.

I feel like fire and pest resistance don't get talked about much as much as other aspects of house construction, leaving me with some knowledge gaps. This thread will hopefully fill some of those gaps.

Let's start with the theoretical "perfect wall"--see the diagram below. Ideally every exterior wall, and the roof too, would be formed like this.

Where do fire resistance (both from fires outside and fires inside) and pest (wood-destroying insects in particular) fit into the perfect wall? What sorts of products, treatments would be used, and if it isn't obvious, how do they work?

PS. In the US at least, modern houses with attached garages are required to have drywall on all garage walls and ceilings, ostensibly for the aim of fire prevention. I'm not sure, but some OSB sheathing products might be required to have a fire retardant treatment as well. (Fire-treated OSB is definitely required in some commercial construction applications.) But I don't want to put drywall or OSB in my house, so what are alternatives?

PPS. In Australia, aren't all the exterior-wall structural members of houses commonly treated for termites? And if they are, how are they treated? In any case, such treatment is not common in the US. Should it be?

Cob and plaster meet the fire resistance need.

The air barrier is the tough one for natural materials. Most of the other issues can be addressed by methods more than materials.

Ned, I think this is another one of those situations where people want a "building code" or a "best practice" that works for a whole country.

Alas, there's a *huge* difference in what a house needs in coastal BC, vs Ontario. A local builder friend told my son that many of the houses built here after 2000, used things like "house wrap" and "sealed everything", rather than the leakier houses built in the 1970'd. So what's happening is that these new, sealed houses are getting mold in the walls and are rotting from the inside out.

A concrete example: I kept getting black mold on the aluminium window frames in the bedroom. I'd clean it up, but it would just keep coming back during the winter rainy season. I finally insisted that Hubby move the portable dehumidifier up to the bedroom. I run it for 1-2 hours every morning in the rainy season and no more mold problem.

Similarly "code" says that so long as you have a window in the bathroom, you don't need a fan, so that's what the ensuite bathroom is like. A window doesn't actively exhaust the humid shower air - in our climate, it's just as humid outside as in! So that dehumidifier now gets pointed at the bathroom and run for 30-60 min after a shower. (We save the dehumidifier water and use it to wash our laundry, so it's not wasted!)

This is completely opposite to my sister who is always trying to *add* humidity to her house in the winter.

TLDR - how you manage risks is dependent on your ecosystem. I am considered to be in a fire risk area. Plastic siding would be out of the question. Concrete boards, or mud would be much safer! Metal roofing with very careful vent protection is also critical in fire areas.

Wood/plastic will always burn, because it's flammable. Wood will also attract pests and they will always find the way, because they are small, patient and come in thousands. Any cavity in framed building will be inhabited sooner or later.
Solid masonry solves these problems.