"Today, we begin a multiple-week series on fire flow. There are few topics in the fire service that generate as much discussion as water supplies for fire protection. How much water is enough? There is no single 'correct' method for establishing fire flow in the structural fire protection world; the overall objective is to provide enough water effectively at the right place to suppress the heat energy released by the fire and protect exposures. The availability of the water supply and the fire department's pumping capacity to deliver flow may be the limiting factors."
Coffee Break Training - Fire Protection Series No. FP-2013-36
United States Fire Administration: http://www.usfa.fema.gov/