I got my place insulated when i moved in, so every room is now a Celotex box. I remember wondering how they made it fireproof, but never looking into it. Mind

I got my place insulated when i moved in, so every room is now a Celotex box. I remember wondering how they made it fireproof, but never looking into it. Mind you, it's a garret in a mansard roof, so before the Celotex it was just wood and bitumen, not exactly fireproof either.