Final answer:
The primary concern for firefighters when determining the collapse zone for a type 5 structure on fire is the potential for structural collapse.
Step-by-step explanation:
In regard to determining the collapse zone for a type 5 structure on fire, the primary concern for firefighters is the potential for structural collapse.
When a fire occurs in a building, it can weaken the structure, causing it to become unstable and potentially collapse. This presents a significant danger to firefighters and anyone else in the vicinity.
To ensure their safety, firefighters establish a collapse zone, which is an area around the burning structure where they maintain a safe distance. This zone is determined based on factors such as the type of structure, the presence of smoke or flames, and the extent of the fire damage.