During which stage does the fire reach a point where it can no longer be suppressed easily?

The fully developed stage of a fire is characterized by the maximum level of heat and the spread of flames throughout the combustible materials present. At this point, the fire has reached a size and scale that make it exceedingly difficult to suppress or control effectively. The fuel is being consumed rapidly, and the intensity of the heat release significantly increases, creating conditions that can be hazardous to people attempting to extinguish it. Firefighters will often focus on containment and protecting surrounding areas during this stage rather than direct suppression. Understanding this stage is crucial for effective fire safety management, especially in environments like homeless shelters, where protecting vulnerable populations is paramount.