Which type of foam system is designed for high expansion?

The choice of a foam system designed for high expansion is indeed the correct one. High-expansion foam systems are specifically formulated to create a large volume of foam that can fill spaces quickly, which is particularly useful in enclosed areas such as aircraft hangars or storage buildings filled with flammable materials. This type of foam works by combining foam concentrate with air to produce a foam that can expand to many times its original liquid volume.

CAFS, or Compressed Air Foam Systems, utilize compressed air to expand the foam and are versatile in their application, allowing for both high-expansion in certain scenarios and effective coverage over surfaces. The use of CAFS is advantageous in providing better coverage and reducing water usage compared to traditional foam systems.

Low-expansion foam systems, on the other hand, are designed to cover surfaces with a thicker blanket of foam rather than expanding significantly in volume. Class B units generally refer to those designed to combat flammable liquids, and water fog systems utilize a fine mist of water rather than foam, making them more suitable for cooling rather than smothering flames. Thus, while each system has its applications, it is the high-expansion foam systems that excel in environments needing rapid volume and area coverage.