1. What is a Fire Flow Test Calculator?

Definition: This calculator estimates the fire flow rate (in gallons per minute) from hydrant test data using pitot pressure measurements.

Purpose: It helps fire protection professionals determine water availability for firefighting operations and system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Fire flow rate (gallons per minute)
• \( C \) — Coefficient (dimensionless, typically ~0.9)
• \( D \) — Outlet diameter (inches)
• \( P \) — Pitot pressure (psi)

Explanation: The formula calculates the theoretical water flow from a hydrant nozzle based on pressure and diameter measurements.

3. Importance of Fire Flow Testing

Details: Accurate fire flow calculations ensure adequate water supply for firefighting, proper system design, and compliance with fire protection standards.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is the typical coefficient value?
A: Most hydrant outlets use a coefficient of 0.9, but this may vary based on nozzle design.

Q2: How do I measure pitot pressure?
A: Use a pitot gauge at the center of the flowing stream, typically 1/2 the outlet diameter from the nozzle tip.

Q3: What are common outlet diameters?
A: Standard hydrant outlets are typically 2.5 inches, but other sizes may be used.

Q4: Why is fire flow important?
A: It determines the available water supply for firefighting operations and influences fire protection system design.

Q5: How accurate is this calculation?
A: It provides theoretical flow; actual flow may vary due to system conditions, friction loss, and other factors.