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A 1/2 inch thick gypsum wallboard typically provides a fire-resistance rating of 30 minutes when used in wall assemblies that are designed for this purpose. However, the context and specific assembly dictate the actual fire-resistance rating. For standard applications, gypsum board acts as a fire barrier due to its core composition, which includes water, aiding in delaying the spread of fire.
Regarding other options, finishes that provide shorter durations, such as 5 seconds or 15 minutes, do not align with standard drywall ratings. Additionally, a 1-hour rating generally requires thicker wall assemblies or additional fire-rated materials beyond standard 1/2 inch gypsum wallboard to achieve that level of fire resistance. Thus, while 30 minutes is a typical resistance for this thickness under certain conditions, it’s important to understand that the assembly type, installation, and additional components can significantly influence performance.