Which class of construction is considered noncombustible?

Masonry Noncombustible is classified as noncombustible because it consists of materials that do not ignite or sustain combustion under fire conditions. This classification encompasses structures built primarily of masonry materials such as brick, stone, and concrete, which have low fire risk and can withstand high temperatures.

In the context of building codes and insurance, Masonry Noncombustible construction provides a significant level of fire resistance, making it safer in terms of fire safety and insurance liabilities. This characteristic is particularly important in commercial and industrial applications, where protecting assets and ensuring safety are priorities.

The other classes of construction mentioned are more prone to combustion. Frame construction, for instance, primarily utilizes wood, which is highly combustible. Joint Masonry can incorporate combustible materials in the structural framework, reducing its fire-resistive properties compared to pure masonry. Modified Fire Resistive construction can include both noncombustible and combustible materials, depending on modifications made, but it does not provide the same level of fire resistance as true noncombustible categories like Masonry Noncombustible.