Determining The Strength
When exposed to temperatures between 570°F and 750°F, the iron contained in the limestone decomposes, leaving behind a red residue. Higher temperatures causes the color to turn to black. Once 1500°F is reached, the blocks are reduced to powdery ash. This is how the researchers were able to determine the strength of each individual stone.
Water Damage
Another problem the restoration workers faced was water damage that had made its way into the ruins. Firefighters were instructed to aim water away from the ancient and quite fragile stained glass windows. However, they weren’t able to do the same for the stone vault, which was directly threatened by the fire.