On what type of fire would you ideally use low-expansion foam?

Low-expansion foam is specifically effective for battling hydrocarbon fires, which are flames fueled by petroleum products such as gasoline, oil, or other flammable liquids. This type of foam works by creating a blanket that smothers the fire and prevents oxygen from reaching the burning material, thereby extinguishing the flames effectively.

The foam's low expansion ratio allows it to adhere to the fuel's surface, forming a protective layer that reduces flammable vapors, stabilizes the burning liquid, and prevents re-ignition after the initial fire is extinguished.

While other types of fires, such as wood or electrical fires, may require different suppression methods – such as water or dry chemical extinguishers – low-expansion foam is not designed for those fire types. In the case of metal fires, specialized agents are necessary due to the unique burning characteristics of metals, which do not coexist well with foam. Thus, low-expansion foam is clearly suited for the specific challenges presented by hydrocarbon fires.