The first foam fire extinguisher was invented in 1905 by Russian inventor Aleksandr Loran (Alexander Laurent). The extinguisher is filled with a solution of water and foam compound (usually aluminum sulphate) in an inner tube, and sodium bicarbonate in the outer portion of the can. When the extinguisher is turned on its end, the chemicals mix together and form carbon dioxide, which helps pressurize the extinguisher. The bubbles from the carbon dioxide mix with the foam compound to form a white/brown foam that is discharged from the extinguisher hose.

Today, foam extinguishers are generally divided into two categories: chemical foam extinguishers, in which the energy used to expel the foam comes from the chemical reaction happening inside the extinguisher, and mechanical foam extinguishers, which contain pre-mixed foam and gather the energy to expel the foam from an outside source. The majority of the foam extinguishers in the Koorsen Fire Museum collection are chemical foam extinguishers, and come from notable brands such as Pyrene, Foamite, and Fyr-Fyter.