I understand the concept of cooperative play. I've played Ars Magica, for instance. But this whole loosie goose approach to the rules is an entirely different animal, and one I'm unaccustomed to. I'll try to adapt my thinking.
A lot of role playing games -- especially some of the older ones -- try to have a rule for everything. There's a rule for falling, and a rule for fire, and a rule for how long you can hold your breath. This results in a lot of support, but also a lot of rules.
The way most Fate games work is by giving you a small number of rules, showing you how you might apply them, and then letting you use the tools you need to run the game you want. And those rules apply to story logic, not to physics logic.
So let's look at a burning room.
The obvious thing to do is slap an Aspect on it. This opens up your typical suite of options, with players invoking it, compels happening, and all that.
For whatever reason, you decide that's not enough. You want the fact that the room is burning to be way more important than that. You want it to really up the danger. How do you do that?
Environmental hazards (page 325) are one place to start. You want this to be pretty dangerous, so you assign a hazard rating of +4, and you give it weapon:3. Now, being in or crossing the zones that are on fire is frigging dangerous.
Or maybe that's too harsh. Hm, what else could you do?
A block seems reasonable. So you assign it a rating based on how hard you think it is to cross that area. Now anyone who wants to cross the fire has to bypass the block somehow.
A maneuver also seems reasonable. Anyone in a fire based zone needs to resist a maneuver to place some Aspect such as, "Choking on smoke," on them. Anyone affected gets free tagged into choking helplessly, which they can resist either by rolling better on the maneuver or by spending a fate point.
The reason there isn't one standard way of handling a room being on fire is that its importance to the story varies from instance to instances. Sometimes it's a coat of narrative spray paint. Sometimes it's the central conflict of the scene. Having one carefully defined set of rules to cover all house fires means that sometimes you're going to be fighting the rules to use them in a particular scene.