Which type of collapse poses the greatest risk for secondary collapse?

The type of collapse that poses the greatest risk for secondary collapse is cantilever collapse. In a cantilever collapse, portions of the structure may remain supported on one side while the other side falls, creating an unstable situation where sections of the structure can easily shift or collapse further. This can lead to additional loads being placed on adjoining areas or floors that are still standing, increasing the risk of a secondary collapse.

Understanding the dynamics of a cantilever collapse is crucial for firefighters, as the unpredictable nature of how remaining parts of the structure may behave poses significant dangers during operations. Awareness of this collapse type enables firefighters to make informed decisions regarding their safety and the safety of others in the vicinity during structural firefighting operations. Other collapse types, while dangerous, typically do not create the same kind of precarious balance that can lead to secondary incidents as effectively as a cantilever collapse does.