1. What is a Hose Monster Hydrant Calculator?

Definition: This calculator estimates the flow rate from a fire hydrant using the Hose Monster formula, which considers discharge coefficient, outlet diameter, and pitot pressure.

Purpose: It helps firefighters and water system engineers determine hydrant flow capacity for firefighting operations and system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( c \) — Discharge coefficient (dimensionless, typically 0.9)
• \( d \) — Outlet diameter (inches, typically 2.5")
• \( P \) — Pitot pressure (psi)

Explanation: The formula calculates flow rate based on the hydraulic principles of water discharge through an orifice.

3. Importance of Hydrant Flow Calculation

Details: Accurate flow rate estimation ensures proper firefighting water supply, helps identify system deficiencies, and verifies hydrant performance.

4. Using the Calculator

Tips: Enter the discharge coefficient (default 0.9), outlet diameter (default 2.5 inches), and pitot pressure in psi. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient?
A: Most hydrants have a coefficient around 0.9, but this can vary based on hydrant design and condition.

Q2: Why is outlet diameter squared in the formula?
A: Flow area increases with the square of the diameter, significantly impacting flow rate.

Q3: How do I measure pitot pressure?
A: Use a pitot gauge at the center of the water stream from the hydrant outlet.

Q4: What's the practical range for this calculation?
A: The formula works best for pressures between 20-100 psi and standard hydrant outlet sizes (2.5"-4.5").

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