What is likely to ignite at 1,300°F in the free-burning phase?

In the free-burning phase of a fire, temperatures can reach approximately 1,300°F (704°C). At this intense heat, an environment becomes highly conducive to the ignition of various combustible materials. Specifically, the higher part of the room often contains combustible materials such as curtains, furniture, or other furnishings that can easily catch fire. As hot gases rise, they pool at the ceiling level, increasing the chances of ignition for those materials.

When a fire reaches this temperature, any combustible items present in that area are susceptible to ignition due to the high thermal energy saturating that part of the room. Thus, it’s not just a single material at risk, but rather a category of items that could likely ignite. Firefighters’ gear, metal objects, and plastic materials react differently to high temperatures and may not ignite as readily compared to other combustible materials. Metal objects might conduct heat but do not ignite, and firefighters' gear is designed to resist burning, while plastics have different ignition points and might not reach combustibility at this stage. Therefore, the correct choice is the combustible materials located in the higher part of the room.