Are modern structure fires considered to be fuel limited or ventilation limited?

Modern structure fires are primarily considered ventilation-limited. This perspective stems from the changing materials used in construction and furnishings over the years. Contemporary buildings often contain synthetic materials that produce more combustible gases.

In a ventilation-limited scenario, the fire is constrained by the amount of oxygen available for combustion. If there is inadequate ventilation, the fire can smolder and produce large quantities of smoke and harmful gases without achieving its peak temperature. This condition limits how quickly and severely the fire can develop, creating the phenomenon known as "flashover" when sufficient ventilation occurs.

Understanding that today's structures are built tighter, with fewer gaps for air exchange, further reinforces why ventilation limits fire growth. If adequate ventilation is not provided, fires can be suppressed or maintained at lower intensity levels until access to fresh air is available, leading to rapid fire escalation once the conditions change.

Ultimately, recognizing that modern fires are primarily ventilation-limited is crucial for effective firefighting tactics and strategies, such as venting smoke and heat to improve air quality and reduce risks to firefighters and any potential victims.