Pipe Size Based on GPM

Pipe Diameter Formula:

\[ D = \sqrt{\frac{4 \times Q}{V \times \pi \times 7.481}} \]

Pipe Diameter (D):

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1. What is Pipe Size Based on GPM?

Definition: This calculator determines the required pipe diameter based on flow rate (GPM) and fluid velocity (ft/s).

Purpose: It helps engineers, plumbers, and designers select the appropriate pipe size for fluid systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ D = \sqrt{\frac{4 \times Q}{V \times \pi \times 7.481}} \]

Where:

\( D \) — Pipe diameter (feet)
\( Q \) — Flow rate (gallons per minute)
\( V \) — Fluid velocity (feet per second)
\( \pi \) — Pi (approximately 3.1416)
7.481 — Conversion factor (gallons to cubic feet)

Explanation: The formula calculates the minimum pipe diameter needed to maintain the desired flow rate at the specified velocity.

3. Importance of Proper Pipe Sizing

Details: Correct pipe sizing ensures efficient flow, prevents excessive pressure drops, and avoids erosion from high velocities.

4. Using the Calculator

Tips: Enter the flow rate in GPM and desired velocity in ft/s (default 5 ft/s for water). 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, with 5 ft/s often used as a standard design value.

Q2: How do I convert the result to inches?
A: Multiply the result by 12 (1 foot = 12 inches).

Q3: What if my flow rate is in cubic feet per second?
A: First convert to GPM by multiplying by 448.831.

Q4: Does this account for friction losses?
A: No, this calculates minimum diameter based on velocity only. Friction losses require additional calculations.

Q5: What's the 7.481 factor in the formula?
A: It converts gallons to cubic feet (1 cubic foot = 7.481 gallons).