To be classified as an initial attack pumper, what is the required minimum size of fire supply hose according to NFPA 1901?

To be classified as an initial attack pumper, the fire supply hose must be a minimum of 2 1/2 inches in diameter according to NFPA 1901. This standard is established to ensure that fire apparatus has the capability to deliver sufficient water flow to effectively combat fires during initial attack operations. The 2 1/2-inch hose size strikes a balance between manageability for firefighters and the ability to deliver the necessary volume of water to suppress a fire.

Larger diameter hoses, such as 3 inches or larger, might be used for supply needs but are not required for initial attack purposes, while hoses smaller than 2 1/2 inches, like those at 2 inches or 1 inch, would generally not provide adequate flow necessary for initial firefighting efforts. The specification in NFPA 1901 recognizes the critical role that initial attack pumpers play in fire operations, necessitating a hose size that can deliver a more substantial water volume for effective fire suppression.