1. What is a Flow in Pipe Calculator?

Definition: This calculator estimates the flow rate in gallons per minute (GPM) through a pipe based on fluid velocity and pipe cross-sectional area.

Purpose: It helps engineers, plumbers, and fluid system designers determine pipe flow rates for system design and analysis.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( V \) — Fluid velocity (feet per second)
• \( A \) — Cross-sectional area of pipe (square feet)
• 448.83 — Conversion factor (cubic feet to gallons and seconds to minutes)

Explanation: The velocity multiplied by area gives volumetric flow in cubic feet per second, which is then converted to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation ensures proper pipe sizing, system efficiency, and prevents issues like excessive pressure drop or cavitation.

4. Using the Calculator

Tips: Enter the fluid velocity in ft/s and pipe cross-sectional area in ft². For circular pipes, area = π × (diameter/2)². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical velocity for water in pipes?
A: For water, 4-8 ft/s is common in supply lines, while 2-5 ft/s is typical for drainage.

Q2: How do I find the cross-sectional area?
A: For circular pipes: A = π × r² (r = radius in feet). For other shapes, use appropriate area formulas.

Q3: Why is the conversion factor 448.83?
A: It combines 7.48052 (gallons per cubic foot) and 60 (seconds per minute): 7.48052 × 60 ≈ 448.83.

Q4: Does this work for any fluid?
A: Yes, but the formula assumes incompressible flow. For gases or compressible fluids, additional factors are needed.

Q5: What if I know diameter instead of area?
A: First calculate area: A = π × (diameter/2)², then use that value in the calculator.