Which is one of the four key characteristics affecting the behaviour of building materials under fire conditions?

Thermal conductivity is indeed one of the four key characteristics that significantly influence the behavior of building materials under fire conditions. This property refers to a material's ability to conduct heat. In a fire scenario, materials with high thermal conductivity transfer heat more readily, which can lead to faster ignition, increased spreading of flames, and quicker degradation of the material itself. This characteristic is critical for understanding how long a structure may withstand fire exposure and how effectively fire can be controlled.

Materials with lower thermal conductivity can act as insulators, providing some resistance to heat transfer, thereby potentially improving fire resistance and limiting damage. Understanding thermal conductivity helps firefighters and fire safety professionals assess the risk of materials used in constructions and develop strategies for fire prevention and suppression.