1. What is a Fire Hose GPM Calculator?

Definition: This calculator estimates the flow rate (in gallons per minute) of water through a fire hose based on the nozzle coefficient, hose diameter, and water pressure.

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( C \) — Nozzle coefficient (dimensionless, typically 0.95-0.98)
• \( d \) — Hose diameter (inches)
• \( P \) — Pressure (psi)

Explanation: The formula calculates flow rate by considering the hose's physical characteristics and the water pressure.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation ensures proper water delivery for firefighting, helps select appropriate pump sizes, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the nozzle coefficient (default 0.95), hose diameter in inches, and pressure in psi. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical nozzle coefficient?
A: Most fire nozzles have coefficients between 0.95 and 0.98, with 0.95 being a common default value.

Q2: How does diameter affect flow rate?
A: Flow rate increases with the square of the diameter - doubling the diameter quadruples the flow rate.

Q3: Why is pressure under a square root?
A: The square root relationship accounts for the energy conversion from pressure to velocity.

Q4: What's a typical fire hose diameter?
A: Common diameters are 1.5", 1.75", 2.5", and 3" for handlines; larger for supply lines.

Q5: Does this account for friction loss?
A: No, this calculates theoretical flow at the nozzle. Actual flow may be less due to hose friction.