What is the typical size of an initial interior attack handline?

• A. 2 1/2 inch delivering about 250 gpm
• B. 1 3/4 inch (approximately 38 mm) delivering about 150 gpm
• C. 1 inch delivering about 60 gpm
• D. 3 inch delivering about 500 gpm

Answer: (B)

Choosing a handline for an initial interior attack requires balancing maneuverability with enough water to rapidly begin suppression. The typical choice is a 1 3/4-inch line delivering about 150 gallons per minute. This size is small enough to easily maneuver through doors, stairs, and tight spaces, while still providing sufficient flow to start knocking down the fire and creating a survivable path for firefighters. Larger lines, like 2 1/2 inches, can push more water but are heavier and stiffer, making interior navigation harder and often unnecessary for a first entry. A 1-inch line is lighter but generally cannot deliver the needed flow quickly, which can prolong heat and fire growth. A 3-inch line offers very high flow suitable for master streams and exterior use, but it’s unwieldy for interior access and would impede rapid initial attack.