What component is primarily responsible for fire resistance in "Type X" drywall?

The component primarily responsible for fire resistance in "Type X" drywall is glass fibers. These fibers are integrated into the drywall formulation to enhance its structural integrity and fire-resistive properties. When exposed to high temperatures, the glass fibers help to prevent the drywall from crumbling or losing its structural support, thereby extending the material's ability to withstand fire.

The addition of glass fibers contributes significantly to the overall performance of Type X drywall in fire-rated assemblies, as they improve its resistance to heat. This characteristic is essential in applications where fire protection is critical, such as in commercial buildings, multi-family housing, and areas requiring enhanced safety measures.

Other options present factors that may contribute to various construction materials or methods, but they do not specifically attribute the fire resistance characteristic of Type X drywall directly to its properties as effectively as glass fibers do.