To determine a safe water supply duration for an attack line, which factors are estimated?

• A. Calculate building layout and occupant load.
• B. Estimate required nozzle pressure, friction loss, hose length, pump discharge, and duration until flow is achieved.
• C. Determine crew rest times and shift lengths.
• D. Assess weather and wind conditions.

Answer: (B)

Estimating the safe water supply duration for an attack line hinges on understanding the hydraulic setup and how long you can sustain it. The key factors are the nozzle pressure you plan to maintain, the friction losses along the hose and fittings, the total hose length, the pump’s discharge capacity, and the time needed to achieve a steady flow once the system is charged. Together, these tell you how much water can be delivered over time and whether you’ll maintain adequate pressure during the attack. The other options don’t directly determine the duration of water supply: building layout and occupant load relate to fire operations and priorities, crew rest and shift lengths concern personnel management, and weather conditions affect fire behavior but not the basic hydraulic duration of the water supply.