Fire Hose Flow Calculator

Fire Hose Flow Formula:

\[ Q = C_d \times A \times \sqrt{\frac{2 \times \Delta P}{\rho}} \times 448.83 \]

Discharge Coefficient (C_d):

Nozzle Area (A):

ft²

Pressure Difference (ΔP):

psi

Fluid Density (ρ):

lb/ft³

Flow Rate (Q): GPM

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1. What is a Fire Hose Flow Calculator?

Definition: This calculator estimates the flow rate of water through a fire hose based on nozzle characteristics and pressure conditions.

Purpose: It helps firefighters and emergency personnel determine water flow rates for effective fire suppression.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = C_d \times A \times \sqrt{\frac{2 \times \Delta P}{\rho}} \times 448.83 \]

Where:

\( Q \) — Flow rate (gallons per minute)
\( C_d \) — Discharge coefficient (dimensionless)
\( A \) — Nozzle area (square feet)
\( \Delta P \) — Pressure difference (psi)
\( \rho \) — Fluid density (pounds per cubic foot)

Explanation: The formula calculates the theoretical flow rate based on Bernoulli's principle, with a conversion factor to get GPM.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate water supply for firefighting, proper nozzle selection, and effective pump operation.

4. Using the Calculator

Tips: Enter the discharge coefficient (default 0.97 for smooth nozzles), nozzle area in square feet, pressure difference in psi, and fluid density (default 62.4 lb/ft³ for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient for fire nozzles?
A: Most smooth-bore nozzles have C_d ≈ 0.97, while fog nozzles range from 0.75-0.95 depending on design.

Q2: How do I calculate nozzle area?
A: For circular nozzles, A = π × (diameter/2)². Remember to convert diameter to feet if measured in inches.

Q3: What pressure difference should I use?
A: Use the nozzle pressure (typically 50-100 psi for handlines, 100-300 psi for master streams).

Q4: When would fluid density change?
A: Density changes with temperature or if using foam solutions. Water at 60°F is 62.4 lb/ft³.

Q5: Why the 448.83 factor?
A: This converts cubic feet per second to gallons per minute (1 ft³/s = 448.83 GPM).