According to NFPA 20, the minimum rated capacity of a fire pump is typically 250 gallons per minute (GPM). However, fire pumps can have higher capacities depending on factors such as the size of the protected area, the hazard classification, and the specific requirements of the local fire department or authority having jurisdiction.

It's important to note that the GPM requirement for a fire pump is determined based on factors like the number and type of sprinklers, hose streams, and other firefighting equipment that the system is designed to supply. Therefore, it's advisable to consult with a fire protection engineer or the local fire department to determine the specific GPM requirements for your intended application.