Which hose diameter is commonly used as both supply and attack lines on firefighting apparatus?

Which hose diameter is commonly used as both supply and attack lines on firefighting apparatus?

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

Answer: (A)

Water flow and hose handling depend on diameter. A 65 mm hose (about 2.5 inches) hits a practical sweet spot: it can deliver a strong water stream without the weight and stiffness of larger lines, making it easy to maneuver as a handline, yet still capable of supplying substantial flows when used as an attack line. Because many rigs stock and train with this size as a standard, it also serves well as a supply line—bringing water to the pump or from a hydrant to a relay—without needing a different hose on the truck. Smaller diameters carry less water and are typically reserved for lighter tasks, while much larger diameters are used mainly for bulk supply rather than direct handline attack due to heavy weight and limited maneuverability. So, the 65 mm option is the most versatile choice for both supply and attack roles.

Water flow and hose handling depend on diameter. A 65 mm hose (about 2.5 inches) hits a practical sweet spot: it can deliver a strong water stream without the weight and stiffness of larger lines, making it easy to maneuver as a handline, yet still capable of supplying substantial flows when used as an attack line. Because many rigs stock and train with this size as a standard, it also serves well as a supply line—bringing water to the pump or from a hydrant to a relay—without needing a different hose on the truck. Smaller diameters carry less water and are typically reserved for lighter tasks, while much larger diameters are used mainly for bulk supply rather than direct handline attack due to heavy weight and limited maneuverability. So, the 65 mm option is the most versatile choice for both supply and attack roles.