GPM Based on Pressure and Pipe Size

Flow Rate Formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Upstream Pressure (P₁):

psi

Downstream Pressure (P₂):

psi

Fluid Density (ρ):

lb/ft³

Pipe Diameter:

inches

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is GPM Based on Pressure and Pipe Size?

Definition: This calculator estimates the flow rate in gallons per minute (GPM) through a pipe based on pressure differential and pipe diameter.

Purpose: It helps engineers, plumbers, and fluid system designers determine flow rates for various applications.

2. How Does the Calculator Work?

The calculator uses these formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Where:

\( V \) — Velocity (feet per second)
\( P_1 \) — Upstream pressure (psi)
\( P_2 \) — Downstream pressure (psi)
\( \rho \) — Fluid density (pounds per cubic foot)
\( Q \) — Flow rate (gallons per minute)
\( A \) — Cross-sectional area of pipe (square feet)

Explanation: The pressure difference drives the fluid flow, with velocity determined by the Bernoulli equation, and flow rate calculated from velocity and pipe area.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation ensures proper system design, adequate water supply, and efficient operation of fluid systems.

4. Using the Calculator

Tips: Enter the upstream and downstream pressures in psi, fluid density (default 62.4 lb/ft³ for water), and pipe diameter in inches. P₁ must be greater than P₂.

5. Frequently Asked Questions (FAQ)

Q1: What's the 144 factor in the equation?
A: This converts psi (lb/in²) to lb/ft² (1 ft² = 144 in²).

Q2: Why 448.83 in the flow rate formula?
A: This converts ft³/s to GPM (1 ft³/s = 448.83 GPM).

Q3: What's a typical fluid density?
A: Water is 62.4 lb/ft³ at 60°F. For other fluids, use their specific density.

Q4: Does this account for friction losses?
A: No, this is ideal flow. For real systems, consider additional pressure drops.

Q5: What pipe sizes can I use?
A: The calculator works for any diameter, but results are most accurate for turbulent flow in standard pipe sizes.