According to NFPA 13, for a high rise building sprinklered throughout, that has four stairwells,...

For a high-rise building sprinklered throughout with four stairwells each having a Class I standpipe system, the maximum flow rate required to be calculated is typically 1,000 gpm (3,785 L/min). This accounts for the demand of both the standpipe system and the sprinkler system in a combined scenario.

References: NFPA 14 sets the standard for the installation of standpipe and hose systems, and it specifies the minimum flow rates required based on the number of standpipes and the type of building occupancy.