Which void type is characterized by collapsing floors and walls leaning inward?

The correct choice describes a lean-to void, which occurs when a building's structural elements fail, causing the walls to lean inward while the floors may collapse. This situation typically arises during a fire when structural integrity is compromised, often due to the weight of the floors above pressing down on weakened supports.

In a lean-to void, the escape paths can be compromised, making it crucial for firefighters to recognize this condition to avoid becoming trapped or injured. By understanding the characteristics of lean-to voids, firefighters can develop strategies for safe navigation and rescue operations within a collapsing structure.

Other types of voids, such as the V-shaped void and pancake void, exhibit different collapse patterns and structural failure characteristics. The V-shaped void usually forms a triangular shape, often indicative of a more open space where materials are not pressing inwards like in a lean-to situation. Pancake voids are characterized by layers of floors that collapse directly on top of one another, creating a stacked effect rather than inward leaning. Individual voids typically refer to isolated spaces created by specific structural failures but do not encompass the overall inward collapse that defines a lean-to void. Understanding these distinctions is important for situational awareness during firefighting operations.