What is necessary for fire and smoke characteristics of rigid-foam insulation board?

Rigid-foam insulation board, while effective for thermal insulation, typically has inherent fire and smoke characteristics that necessitate additional precautions. The correct answer highlights the requirement for a fire-resistant layer to be applied over the insulation. This is essential because the foam can be flammable and can produce harmful smoke when exposed to fire.

The fire-resistant layer serves as a barrier that helps to prevent flames from easily igniting the foam insulation and reduces the amount of heat transferred to it. This protective layer enhances the fire safety of the building by slowing down combustion and providing additional time for occupants to evacuate in case of a fire.

Adding a fire-resistant covering is a common practice in building codes and safety standards to mitigate risks associated with fire hazards in homes and buildings. This ensures that the insulation meets safety ratings and complies with local regulations.