Final answer:
One key characteristic affecting building material behavior under fire conditions is thermal conductivity, which determines how well a material can conduct and transfer heat during a fire.
Step-by-step explanation:
One of the four key characteristics affecting the behavior of building materials under fire conditions is thermal conductivity. This property determines how well a material can conduct heat. During a fire, materials with high thermal conductivity can transfer heat rapidly, potentially causing fire to spread more quickly. Examples of good thermal conductors are metals. On the other hand, materials with low thermal conductivity, such as insulators, tend to slow down the transfer of heat, thus potentially slowing the spread of fire. Understanding the thermal properties of building materials is crucial when designing structures for fire safety.
Flammability is a chemical property that describes a material's ability to ignite and burn. It is directly linked to the material's composition and the presence of combustible elements. While strength and durability are also important properties, they do not directly influence how a material behaves under fire conditions in terms of conducting heat. However, they do play a role in a structure's overall ability to withstand fire damage.