A fire-resistant material is one that maintains its structural integrity in a fire for a specified length of time.

Two of the most effective elements in fire resistance are phosphorus and nitrogen, which are often mixed with polymers (plastics) to form polyphosphazenes.

When used in buildings, fire resistant material can create compartmentalization, or the containment of a fire to a certain area. In the case of the World Trade Center, which burned down and collapsed during the September 11th attacks, compartmentalization gave many building occupants precious extra minutes to escape to safety.

Requirements for fire resistant classification vary from country to country, so testing can look different depending where you are. In the U.S., at least one side of a material must be exposed to direct heat and flame for a specified length of time. A material's resistance is usually recorded on a time/temperature curve to determine its success or failure.

In order to determine fire resistance, materials are assessed based on three qualities: fire penetration (whether the flames can penetrate the material), temperature (how hot the material gets in comparison with established standards) and maintenance of structural integrity (the hose-stream test).

In the event of a fire, you'd probably prefer to be behind a concrete wall than in your silk-sheeted bed. Concrete will eventually degrade under fire, but it handily passes the fire resistance test and is much hardier than most other materials in a fire.

Fire-retardant materials must slow the movement of a fire; however, there is no requirement that structural integrity is maintained. Fire resistance, which does require the structural element, is a more stringent classification.

When used for things like countertops, concrete is often finished with a non-fire resistant wax or sealant. This won't degrade the abilities of the concrete itself to resist flame, but it can cause the surface to ignite where an unfinished slab would not.

Although it's not as pretty, concrete is significantly stronger and more resilient than wood. As a result, it offers greater protection against a wide variety of natural disasters, including hurricanes, tornadoes and floods.

In many older buildings, asbestos was used for insulation and fire resistance; however, it can cause some serious harm to lungs. It's no longer used in construction, but its ill effects can surface years after exposure.