During which stage of a fire is structural integrity more likely to be compromised?

Structural integrity of a building is most likely to be compromised during the fully developed stage of a fire. At this point, the fire has reached its peak temperatures and is producing significant amounts of heat and smoke, causing the building materials to weaken and degrade. The combination of high heat and the duration of exposure leads to critical structural failures, as materials like wood and metal lose their strength and may become unable to support the weight of the structure above.

In this stage, not only are fire conditions at their most dangerous, but also the risk of catastrophic structural failure increases significantly. The fire has consumed much of the available fuel, resulting in a state where it can actively consume any remaining materials. Firefighters, therefore, must exercise extreme caution when operating in environments that are in the fully developed stage to avoid collapse and ensure safety.

While other stages, like growth and decay, do present risks to structural integrity, it is during the fully developed stage that those risks culminate in a critical threat, making it the most dangerous phase regarding structural compromise.