Fire Pump Flow Test Calculator
A fire pump flow test calculator helps you measure pump performance quickly and accurately. It ensures your fire protection system delivers the required flow and pressure. Use this guide to understand, calculate, and verify fire pump performance with ease.
Flow Test Performance Calculator
How to Use a Fire Pump Flow Test Calculator
Follow these simple steps to use a fire pump flow test calculator:
- Enter the discharge pressure (PSI): Enter the reading from the flow test gauge.
- Input the nozzle size: Enter the diameter of the nozzle used (usually 1.0, 1.5, or 2.0 inches).
- Provide the pitot pressure reading (PSI): This is the pressure measured at the nozzle outlet.
- Select the number of outlets: If multiple hoses are flowing, specify the total number.
- Click calculate: Get the total flow rate (GPM) immediately.
Tips for accuracy: Use calibrated gauges, ensure steady water flow, and record multiple readings for better results.
How to Calculate Fire Pump Flow Test
The standard formula used in fire pump flow testing is:
Where:
- Q: Flow rate (GPM)
- C: Coefficient (usually 0.9 for smooth bore nozzle)
- d: Nozzle diameter (inches)
- P: Pitot pressure (PSI)
Step-by-Step Calculation Example
Suppose you have the following test data:
- Nozzle diameter (d) = 1.5 inches
- Pitot pressure (P) = 25 PSI
- Coefficient (C) = 0.9
Step 1: Square the nozzle diameter
d² = 1.5 × 1.5 = 2.25
Step 2: Calculate square root of pressure
√P = √25 = 5
Step 3: Multiply all values
Q = 29.84 × 0.9 × 2.25 × 5
Step 4: Final result
Q = 302 GPM
The fire pump flow rate is approximately 302 GPM.
Fire Pump Flow Test Conversion Chart
| Nozzle Size (in) | Pitot Pressure (PSI) | Flow (GPM) |
|---|---|---|
| 1.0 | 20 | 120 |
| 1.0 | 30 | 150 |
| 1.25 | 20 | 190 |
| 1.25 | 30 | 230 |
| 1.5 | 20 | 270 |
| 1.5 | 25 | 302 |
| 1.5 | 30 | 330 |
| 2.0 | 20 | 480 |
| 2.0 | 30 | 580 |
Note: Values are approximate. Use the calculator for precise results based on your specific coefficient.
Frequently Asked Questions
It is a tool that calculates the flow rate (GPM) of a fire pump using pressure and nozzle data during a physical flow test.
It verifies that the pump meets required performance standards for fire protection systems and ensures it can deliver water in an emergency.
Flow is typically measured in Gallons Per Minute (GPM), pressure in Pounds per Square Inch (PSI), and nozzle size in inches.
Perform it annually or as required by NFPA standards and local fire safety regulations.
It is a correction factor based on the nozzle's shape and efficiency. It is usually 0.9 for smooth bore nozzles.
It is the dynamic pressure measured at the center of the water stream as it exits the nozzle during a flow test.
Yes, you calculate the flow for each hose and sum them up. Our calculator allows you to input the number of outlets for a total GPM result.