What is an effective method for extinguishing Class A fires?

Class A fires involve combustible materials such as wood, cloth, paper, and some plastics, which are common on ships and other environments where fire hazards are present. An effective method for extinguishing Class A fires involves applying water or Aqueous Film-Forming Foam (AFFF).

Water is effective because it cools the burning material below its ignition temperature and helps to eliminate the heat component of the fire triangle, which consists of heat, fuel, and oxygen. Water can also help in some cases to create steam, which can displace oxygen and further suppress the flames.

AFFF is particularly advantageous because it not only cools the fire but also forms a film that can separate fuel from oxygen, providing a dual-action approach to extinguishing the fire. This is especially useful in instances where the materials burning may release flammable vapors or are involved in a deep-seated fire.

Using methods such as CO2, powder extinguishers, or foam only may not effectively address Class A fires. CO2 is better suited for Class B and C fires as it may not remove the heat effectively from Class A materials. Powder extinguishers, while useful in certain applications, may not cool the fire or prevent re-ignition as effectively as