What happens to steel when it is heated in a fire situation?

When steel is heated in a fire situation, it expands and loses strength due to the physical and chemical properties of the metal at elevated temperatures. As the temperature rises, steel typically begins to lose its structural integrity starting around 1,100 degrees Fahrenheit (593 degrees Celsius), and it can lose nearly 50% of its strength at temperatures around 1,800 degrees Fahrenheit (982 degrees Celsius).

This loss of strength makes steel less capable of supporting loads, which can lead to structural failure during a fire. Additionally, steel will also undergo thermal expansion, meaning that it will increase in size with heat. This expansion can create stresses in the connections and fasteners holding structural components together, potentially leading to failure even if the steel itself does not melt.

Understanding the behavior of steel under fire conditions is crucial for fire fighters when assessing building integrity and implementing effective firefighting strategies.