A Rescue Pumper or Rescue Engine is a purpose-built unit of fire apparatus beyond a typical National Fire Protection Association (NFPA ) Class A rated engine company. A current Class "A" rated Engine company must have a fire pump capable of pumping not less than 1,250 US gallons (4,700 L) per minute and carry no less than 750 US gallons (2,800 L) of water in an on board tank, plus specific hose amounts, plus ground ladders. In the late 1980s, the original concept was to marry the pumping capabilities of a heavy rescue squad, and what was then a Class A rated pumper, which was to add 1,000 gpm fire pump or greater and 500 US gallons (1,900 L) of water. Fire Pumper ratings increase as apparatus progress and innovation is made. During the 1960s and '70s a Class A pumper had to carry 300 US gallons (1,100 L) of water and pump 750 US gallons (2,800 L) per minute. There are now pumpers that can easily pump 3,000 gpm or more. It is expected over the next few years, as foam is used more on structure fires, that NFPA should be upgrading the requirements of a Class A pump to 1,500 gpm and probably a 1,000 US gallons (3,800 L) of fire extinguishment agent i. e. : both Class A foam (250 US gallons (950 L)) and water (750 US gallons (2,800 L))or a close combination of these quantities