How is fire resistance rated in building materials?

Fire resistance in building materials is primarily rated by the time that the material can withstand exposure to fire without losing its structural integrity, protecting the integrity of the building, and preventing fire from spreading. This time period is often measured in minutes or hours and is determined through standardized testing methods that simulate fire conditions. These tests evaluate how long a material can maintain its performance under fire exposure, allowing designers, builders, and fire safety professionals to ensure that structures provide adequate protection in the event of a fire.

The other options, while they may relate to the characteristics of materials in a general sense, do not accurately represent how fire resistance is determined. Measuring the weight of the material, the type of material used, or the color of the material are not standard factors in establishing fire resistance ratings. Fire resistance is specifically about performance during fire exposure, making time the critical metric in these assessments.