If you are building a new fireplace or opening a chimney breast to create one, you can line the opening with fire bricks set in place with heatproof mortar or use fireplace board. The mortar joints should be thin: 3 to 5 mm. Generally speaking, 10 kg of heatproof mortar can be used to place 100 standard sized fire bricks. Alternately, you can render over the existing brickwork with Fireplace Render to a thickness of approximately one inch. Heatproof Screed can also be used to create a base for the fire area. Free standing stoves can be lined with Fireplace Render as well.
Consequently, it's not a question of whether a fire can damage a structure, but a question of when. It simply takes longer for fire to affect fire-resistant materials. The key is to construct a building in which a fire would take effect slowly, allowing the occupants plenty of time to escape. This is also why materials themselves are rated in respect to how long it would take fire to affect its structural abilities. Even heavy timber can be considered fire-resistant. It's combustible, however, while metals like aluminum or steel aren't combustible -- instead, they tend to buckle under intense heat.