Which of the following is considered a fireblocking material?

Fireblocking is a critical fire safety mechanism in building construction, designed to prevent the spread of fire and smoke through concealed spaces such as walls, floors, and ceilings. The materials used for fireblocking must effectively create barriers that inhibit the passage of flames and smoke.

2" nominal lumber is commonly used in construction for framing and can serve as an effective fireblocking material, particularly in wood frame construction, where it can help to seal off spaces that could allow fire to spread.

1/2" gypsum board is recognized for its excellent fire-resistant properties. Gypsum board is often used in walls and ceilings to provide a barrier against fire, making it an ideal choice for fireblocking. It can withstand high temperatures and has a significant degree of resistance to flame propagation.

1/4" cement-based millboard is another material that provides fire-resistant qualities. This type of board can be used in various applications to create fire barriers, and its composition is specifically designed to withstand high heat and flames.

Since all three materials—nominal lumber, gypsum board, and cement-based millboard—have fireblocking capabilities, the correct choice encompasses all these options, confirming their use as effective fireblocking materials in construction.