The classification of Type 'X' gypsum board refers to the panel's what?

Type 'X' gypsum board is specifically designed to provide enhanced fire resistance compared to standard gypsum board. This classification signifies that the board has been formulated with special additives and constructed in a way that delays the spread of fire, making it suitable for use in areas that require increased fire safety measures, such as fire-rated walls and ceilings. The fire-resistant properties of Type 'X' gypsum board make it a crucial component in building design, especially in meeting code requirements for fire safety.

While the other options touch on different aspects of gypsum board properties, they do not pertain to the classification of Type 'X.' Water resistance is more closely associated with Type 'C' gypsum board, which is designed for moist environments, while insulating properties and impact durability do not define the 'X' classification and refer instead to different types or qualities of gypsum boards used for other purposes.