Which of the following lists the three most common attack line sizes?

• A. 1-1/4 inch, 1-3/4 inch, and 2 inch
• B. 1-1/2 inch, 1-3/4 inch, and 2-1/2 inch
• C. 1-1/2 inch, 2 inch, and 2-1/2 inch
• D. 1-1/2 inch, 1-3/4 inch, and 2 inch

Answer: (B)

Attack line sizing is about balancing water flow with how easy the line is to handle on the fireground. The three most common handline sizes used for interior attack are 1-1/2 inch, 1-3/4 inch, and 2-1/2 inch. The 1-1/2 inch line is light and easy to maneuver, suitable for smaller fires or initial attack. The 1-3/4 inch line increases flow while remaining manageable for many mid-sized fires. The 2-1/2 inch line delivers the highest flow, useful for larger fires or when rapid, heavy application is needed. This combination covers the typical range of incidents better than including sizes that are less commonly used as standard attack lines.