1. What is the Fire Hose Flow Rate Equation?

The Fire Hose Flow Rate equation calculates the water flow rate from a fire hose based on nozzle diameter and water pressure. This calculation is essential for firefighting operations to determine water delivery capacity.

2. How Does the Calculator Work?

The calculator uses the fire hose flow equation:

Where:

• \( d \) — Nozzle diameter (inches)
• \( P \) — Water pressure (psi)
• 29.7 — Empirical constant for water flow

Explanation: The equation accounts for the relationship between nozzle size, water pressure, and resulting flow rate, with the constant 29.7 derived from fluid dynamics principles for water.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is crucial for firefighting operations to ensure adequate water supply, proper nozzle selection, and effective fire suppression tactics.

4. Using the Calculator

Tips: Enter nozzle diameter in inches and water pressure in psi. All values must be valid (diameter > 0, pressure > 0).

5. Frequently Asked Questions (FAQ)

Q1: What units does this calculator use?
A: The calculator uses inches for nozzle diameter and psi for pressure, with results in gallons per minute (gpm).

Q2: Is this equation accurate for all nozzle types?
A: This equation provides a good estimate for smooth bore nozzles. Fog nozzles and other specialized nozzles may have different flow characteristics.

Q3: What is a typical flow rate for fire hoses?
A: Typical flow rates range from 95 gpm for 1.5" hose to 250+ gpm for 2.5" hose, depending on pressure and nozzle size.

Q4: How does pressure affect flow rate?
A: Flow rate increases with the square root of pressure. Doubling the pressure increases flow rate by approximately 41%.

Q5: Why is the constant 29.7 used?
A: This empirical constant accounts for the coefficient of discharge for water flowing through a circular orifice and unit conversions.