Fire resistance can be omitted on a roof located at what height?

The correct answer, indicating that fire resistance can be omitted on a roof located at a height of 20 feet, is based on building codes and fire safety regulations that take into account the potential reach of fire in relation to a building's height. Generally, these codes establish that as buildings rise in height, the materials and components used must adhere to stricter fire resistance requirements to mitigate the risk of fire spread.

At a height of 20 feet, structures typically do not present the same level of risk for fire spread in the same way that taller buildings do, particularly when considering the exposure that low-rise structures have to adjacent buildings or assembly areas. This height often falls into a category where it is deemed that the risk of having combustible materials nearby is reduced due to natural firebreaks or the distance required by building codes.

In essence, the determination of height limits for fire resistance requirements is a reflection of fire safety principles that allow for a balance between construction costs and safety risks associated with fire.