Fire control consists of depriving a fire of fuel, oxygen or heat (see fire triangle) to prevent it from spreading or to put it out entirely. The standard and most common way to control a class-A fire (the combustion of a flammable material with oxygen and heat) is to remove heat by spraying the burning solid fuels with water from a fire-hose connected to a pump. Other methods of controlling a class-A fire would be to "smother" the fire with carbon dioxide, such as from a fire extinguisher, cutting off its oxygen. In a forest fire, fire control would usually consist of removing fuel in the fire's path and digging trenches—this prevents the fire from gaining new fuel and spreading.