A 1¾" (45-mm) attack hose can generally flow __________.

A 1¾" (45-mm) attack hose is typically designed to deliver a flow rate in the range of 120 to 180 gallons per minute (GPM). This flow rate is considered optimal for most structural firefighting operations, as it provides a good balance of reach and volume necessary to effectively combat fires, especially in residential and commercial buildings.

The design and diameter of a 1¾" hose allow it to handle relatively high pressures while still being manageable for firefighters to maneuver. This size strikes an effective balance between flow and pressure, making it suitable for initial attack lines. The range of 120 to 180 GPM enables firefighters to apply sufficient water to extinguish flames quickly and efficiently, ensuring effectiveness in fire suppression efforts.

While hoses with different diameters can flow more or less water, the specification for the 1¾" hose has been based on industry standards and practical experiences of firefighters in the field, solidifying this flow range as the accepted norm for this size of attack hose.