Fire Extinguisher Mechanical Foam 50 ltr Mechanical foam (AFFF) Gas Cartridge Type extinguishers are ideal for installation in outdoor environments. These fire extinguishers are preferred in warehouses, petrol filling areas and factories where there is a dual risk of solid materials and flammable liquid fires 50 ltrs. Mechanical Foam CO2 type (Gas pressure) fire extinguisher.  to fight burning solids such as wood as well as liquid fires such as burning petrol. The foam has the ability to creep over the burning liquid or to soak into burning materials such as settees