1. What is the GPM Formula?

The GPM (Gallons Per Minute) formula calculates flow rate through a pipe based on pipe diameter and fluid velocity. It's essential for hydraulic system design and fluid dynamics calculations.

2. How Does the Calculator Work?

The calculator uses the GPM formula:

Where:

• \( D \) — Pipe diameter (inches)
• \( v \) — Fluid velocity (feet per second)
• \( 448.83 \) — Conversion factor (cubic inches per second to gallons per minute)

Explanation: The formula calculates the cross-sectional area of the pipe, multiplies by velocity to get volumetric flow, then converts to gallons per minute.

3. Importance of GPM Calculation

Details: Accurate GPM calculation is crucial for proper pump selection, pipe sizing, system efficiency analysis, and ensuring adequate flow for various applications.

4. Using the Calculator

Tips: Enter pipe diameter in inches and velocity in feet per second. All values must be valid (diameter > 0, velocity > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical velocity range for water in pipes?
A: For water systems, typical velocities range from 2-8 ft/s, with 4-6 ft/s being optimal for most applications.

Q2: How does pipe material affect flow rate?
A: Pipe material affects friction loss but not the basic GPM calculation. The formula assumes ideal flow conditions.

Q3: Can this formula be used for other fluids?
A: Yes, but the conversion factor is specific to water. For other fluids, additional density/viscosity factors may be needed.

Q4: What is the maximum GPM for different pipe sizes?
A: Maximum GPM depends on velocity limits. For 2-inch pipe at 6 ft/s: ~73 GPM; 4-inch pipe at 6 ft/s: ~293 GPM.

Q5: How accurate is this calculation?
A: The formula provides theoretical maximum flow. Actual flow may be lower due to friction, elevation changes, and other system losses.