1. What is a Fire Flow Calculator GPM?

Definition: This calculator estimates fire flow rate in gallons per minute (GPM) from hydrant test data using nozzle coefficient, diameter, and pressure.

Purpose: It helps firefighters and water system engineers determine available water flow for firefighting operations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Fire flow rate (gallons per minute)
• \( C \) — Nozzle coefficient (dimensionless, typically 0.9)
• \( D \) — Nozzle diameter (inches)
• \( P \) — Pressure (psi)

Explanation: The formula calculates theoretical water flow based on hydraulic principles, accounting for nozzle characteristics and system pressure.

3. Importance of Fire Flow Calculation

Details: Accurate fire flow estimation ensures adequate water supply for fire suppression, proper hydrant sizing, and effective emergency planning.

4. Using the Calculator

Tips: Enter the nozzle coefficient (default 0.9), 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 standard fire nozzles have a coefficient around 0.9, but this can vary by manufacturer and nozzle type.

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

Q3: Why is pressure under a square root?
A: The square root relationship reflects the physics of fluid flow through an orifice under pressure.

Q4: What's a good fire flow rate?
A: Minimum required fire flows typically range from 500 GPM for residential to 2500+ GPM for commercial/industrial.

Q5: Does this account for friction loss?
A: No, this is theoretical maximum flow. Actual flow may be less due to pipe friction, elevation changes, etc.