What is a key sign that a Type B fire is extinguished?

The absence of flames and smoke is a key indicator that a Type B fire has been successfully extinguished. Type B fires involve flammable liquids, such as gasoline, oil, and solvents. When these fires are active, they typically produce visible flames and may generate smoke as the material burns.

After extinguishing a Type B fire, you should observe a clear and smoke-free environment. The lack of flames indicates that the combustion process has ceased, and the absence of smoke further confirms that there are no residual burning materials or fumes being released. This state ensures that the fire has been fully controlled and mitigated, making the area safe for re-entry and preventing any possibility of reignition.

Other indicators, such as the presence of intense flames or billowing smoke, signify that the fire is still active or that there may be lingering hot spots. Emission of fumes is also a warning sign that combustion has not completely ended, indicating that further precautions may still be necessary. Thus, observing no flames or smoke is the most reliable confirmation of fire extinction.