Which hose diameter can serve as both supply and attack hose?

• A. 38 mm
• B. 65 mm
• C. 45 mm
• D. 100 mm

Answer: (B)

Hose diameter controls both the amount of water you can move and how easy the hose is to handle. A 65 mm hose hits a sweet spot: it can carry a substantial flow to support fire attack and still be light enough and flexible enough to deploy as a handline. That size is commonly used for supply work between hydrants or pumps and for relay laydowns, yet it’s also practical to use at the nozzle for attack on many fires. Smaller diameters are easier to handle but don’t deliver as much water quickly, while the largest sizes excel at supply but are unwieldy for rapid, close-range attack. So 65 mm serves well for both roles.