How do you make steel fire resistant?

When you make steel fire resistant, you are actually protecting it from heat--steel, in a fire, does not burn. There are three ways: The old-fashioned way was to encase the steel in concrete, as was done when the Empire State Building was built. The Fire Department of New York calls the Empire State Building the most fireproof building in America. Then came fluffy, spray-on fire retardants. Asbestos was used for some years until it was banned. The current best technology is intumescent paint--when it's heated to a certain temperature, it foams up and provides an insulating layer.