Which class specifies that everything is constructed of masonry or fire resistive material rated 2 hours or more?

The classification that specifies that everything is constructed of masonry or fire-resistive materials rated for two hours or more is indeed categorized under Class 6 - Fire Resistive. This classification is important because it highlights the use of materials that can withstand fire for a significant duration, reducing the risk of damage in the event of a fire and enhancing safety.

Fire resistive materials significantly contribute to the overall fire safety of a structure, providing essential time for evacuation and firefighting efforts. Class 6 buildings are designed to minimize fire spread and protect occupants, making them ideal for locations that may be at higher risk for fires. The emphasis on masonry or fire-resistive materials rated for two hours or more directly relates to the building's durability and resilience in the face of fire hazards, ensuring a greater level of safety compared to lower-classified structures.

In contrast, the other classifications refer to different structural compositions that do not meet the same criteria for fire resistance as Class 6.