Which building materials are commonly used for fire-rated assemblies?

Gypsum board, concrete, and steel are commonly used for fire-rated assemblies due to their inherent fire-resistive properties.

Gypsum board, also known as drywall, contains a mineral that can withstand high temperatures for a specific duration, contributing to fire resistance in walls and ceilings. This material is often used in assemblies designed to delay the spread of fire between compartments within a building.

Concrete, being a dense material, effectively prevents the passage of heat and smoke. Its mass contributes significantly to the overall fire resistance of walls and floors, making it an excellent choice for structural components in fire-rated assemblies.

Steel is another key material, particularly in structural frameworks. When adequately protected or treated with fire-resistant coatings, steel can maintain its integrity during high temperatures, thus offering fire-resistant characteristics that are crucial in maintaining building safety.

The other options include materials that either do not meet fire-resistance requirements or are less effective in delaying fire spread. For instance, while wood can be part of some fire-rated assemblies under specific conditions, it generally has lower fire-resistance qualities compared to concrete and steel. Similarly, plastic and fiber tend to have lower melting points and can contribute to fire fuel rather than resistance. Therefore, the combination of gypsum board, concrete, and steel