Which term is defined as a material that limits the average temperature rise of an unexposed surface to not more than 250°F (139°C) for a specified fire exposure?

Which term is defined as a material that limits the average temperature rise of an unexposed surface to not more than 250°F (139°C) for a specified fire exposure?

• A. Floor Fire Door Assembly
• B. FireBarrier
• C. Smoke Barrier
• D. Thermal Barrier

Answer: (D)

The term is about limiting heat transfer to the unexposed side of a surface during a fire. A thermal barrier is a layer of material whose job is to keep the average temperature rise on the unexposed surface to no more than 250°F (139°C) for a specified fire exposure. This criterion, used in NFPA 101 definitions, helps protect occupants by slowing heat transfer through interior finishes and similar materials during the fire, without requiring a full fire-resistance rating for the entire assembly. This is different from a fire barrier, which focuses on resisting fire spread with a rated enclosure; a smoke barrier, which controls smoke movement; or a floor fire door assembly, which is a door component used within fire and smoke barriers. The 250°F limit specifically identifies a thermal barrier’s performance in terms of heat transfer to the unexposed side.

The term is about limiting heat transfer to the unexposed side of a surface during a fire. A thermal barrier is a layer of material whose job is to keep the average temperature rise on the unexposed surface to no more than 250°F (139°C) for a specified fire exposure. This criterion, used in NFPA 101 definitions, helps protect occupants by slowing heat transfer through interior finishes and similar materials during the fire, without requiring a full fire-resistance rating for the entire assembly.

This is different from a fire barrier, which focuses on resisting fire spread with a rated enclosure; a smoke barrier, which controls smoke movement; or a floor fire door assembly, which is a door component used within fire and smoke barriers. The 250°F limit specifically identifies a thermal barrier’s performance in terms of heat transfer to the unexposed side.