Coal soot chimney fires can create temperatures up to 1000 degrees centigrade inside the chimney.
Wood tar chimney fires can create temperatures up to 1200 degrees centigrade inside the chimney.
Clay liners - a chimney fire will often cause clay liners to crack and therefore the chimney will probably need to be relined (you may be able to claim for this under your household fire insurance). Contact us for advice or call your insurance company for specific coverages.
As the chimney heats up during the chimney fire, it expands - this causes plasterwork to crack and even blow off and can cause structural damage to the chimney.
On one chimney fire job I observed the headboard of the bed that was against the chimney breast it had been scorched and the plaster looked like an underground subway map. On another job, there had been a wood tar fire to the stone-built chimney. The stones inside the chimney had a glassy sheen as the high temperature inside the chimney had vitrified them!