Steel is a non-combustable material that will not add fuel to the spread of fire. "Unlike a wood structure, steel-framed structure can help safeguard your assets against fire accidents." -BuildSteel.org
"It's a common fact that steel is non-combustible.
The melting point of steel is approximately 2,700 degrees Fahrenheit
Building fire temperatures average 1,000 degrees Fahrenheit, and rarely exceed 1,800 degrees Fahrenheit
Thus, the steel structures will not melt.
While the stiffness and yield strength of steel are reduced at ultra-high temperatures, modern building codes and fire protection methods take these reductions into consideration." -BuildSteel.org