Portable Fire Extinguishers Fire Extinguishers and Charts Tri-Class or ABC: Powder agent, used for many applications and most common. Schools, Offices, Residential, and more. Halatron: Clean agent, used in Data Center, IT Rooms, Server Rooms, or any sensitive applications. Pressurized Water, Only effective on Class "A" fires, used in wood shops etc. Carbon Dioxide, Clean Agent, effective on Class "B" and "C" fires, used in Offices, Data Centers, or Sensitive Equipment is used. "K" Class, Wet Chemical, Used in all Industrial Kitchens.