Which extinguishing method is being used when a foam blanket is placed over the surface of a burning liquid?

The method described involves placing a foam blanket over the surface of a burning liquid, which primarily serves to cut off the oxygen supply to the flames. When foam is applied to a flammable liquid fire, it forms a barrier that restricts the access of oxygen to the fuel. This creation of a foam blanket smothers the fire and prevents oxygen from reaching the burning liquid, effectively suppressing combustion.

In fire suppression, limiting oxygen is a critical tactic due to its role as one of the three components of the fire triangle, which includes fuel, heat, and oxygen. Without sufficient oxygen, the fire cannot sustain itself, leading to its extinguishment.

This method is particularly effective for liquid fires because it not only suppresses the flames but also mitigates the potential for re-ignition by covering the fuel source with foam, which prevents vapor release.

Understanding the different fire suppression methods demonstrates how they align with the principles outlined in the NFPA 1001 standard, emphasizing fire fighter competencies in recognizing and employing appropriate techniques for various fire scenarios.