What is the typical flow for a 1 3/4 inch handline used for interior attack with good mobility?

• A. 200–350 GPM
• B. 50–100 GPM
• C. 125–180 GPM
• D. 300–400 GPM

Answer: (C)

The key idea here is balancing enough water to knock down and cool the fire with keeping the line and crew maneuverable inside a structure. For a 1 3/4 inch attack line used inside with good mobility, you want a flow that provides effective fire control without making the nozzle hard to handle or bogging you down with high friction loss.

Around 125–180 gallons per minute is the sweet spot. This range gives you enough water to cool the surroundings and attack the seat of the fire quickly, which helps prevent a rapid buildup of heat and smoke. At the same time, it keeps nozzle pressure and recoil at a level you can manage while moving through rooms, negotiating obstacles, and repositioning as the fire evolves. If you drop to about 50–100 GPM, you often won’t have enough flow to control the fire effectively from the interior, leading to slower knockdown and more exposure. If you push well above 180 GPM, the additional water comes with higher friction loss and stronger nozzle reaction, which can hinder your ability to advance, maintain a steady stream, and keep visibility in a tight, hot environment.

So, 125–180 GPM best matches the needs of interior attack with good mobility on a 1 3/4 inch line.