Natural Gas Pipe Calculator

Spitzglass Formula for Natural Gas Flow:

\[ Q = 737 \times d^{2.5} \times \sqrt{\frac{P1^2 - P2^2}{G \times T \times L \times Z}} \]

Pipe Diameter (d):

inches

Inlet Pressure (P1):

psi

Outlet Pressure (P2):

psi

Gas Gravity (G):

Temperature (T):

°R

Pipe Length (L):

feet

Compressibility (Z):

Flow Rate (Q): scfh

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1. What is the Spitzglass Formula Calculator?

Definition: This calculator estimates natural gas flow rate through pipes using the Spitzglass equation, which considers pipe diameter, pressure drop, gas properties, and pipe length.

Purpose: It helps engineers and technicians design and analyze natural gas piping systems for residential, commercial, and industrial applications.

2. How Does the Calculator Work?

The calculator uses the Spitzglass formula:

\[ Q = 737 \times d^{2.5} \times \sqrt{\frac{P1^2 - P2^2}{G \times T \times L \times Z}} \]

Where:

\( Q \) — Flow rate (standard cubic feet per hour, scfh)
\( d \) — Internal pipe diameter (inches)
\( P1 \) — Inlet pressure (psig)
\( P2 \) — Outlet pressure (psig)
\( G \) — Gas specific gravity (relative to air)
\( T \) — Absolute temperature (°R = °F + 459.67)
\( L \) — Pipe length (feet)
\( Z \) — Gas compressibility factor (dimensionless)

Explanation: The formula calculates flow rate based on pressure drop across the pipe length, adjusted for gas properties and pipe size.

3. Importance of Natural Gas Flow Calculation

Details: Proper flow calculation ensures adequate gas supply to appliances, maintains safe pressure levels, and helps in proper pipe sizing to avoid excessive pressure drops.

4. Using the Calculator

Tips:

Enter pipe diameter in inches (actual internal diameter)
Pressures can be in psig or psia (formula uses absolute values)
Default gas gravity is 0.6 (typical for natural gas)
Default temperature is 520°R (60°F)
Default compressibility is 1 (ideal gas)

5. Frequently Asked Questions (FAQ)

Q1: When should I use the Spitzglass formula?
A: For low-pressure natural gas systems (typically below 1 psi) with pipe diameters from 0.5 to 24 inches.

Q2: What's the difference between scfh and acfh?
A: SCFH is at standard conditions (60°F, 14.7 psia), while ACFH is actual flow at current conditions.

Q3: How do I find the compressibility factor?
A: For low pressures, Z≈1. For higher pressures, use gas property tables or equations of state.

Q4: What's a typical gas gravity for natural gas?
A: Typically 0.55 to 0.7, with 0.6 being a common average value.

Q5: Can I use this for other gases?
A: Yes, but you must adjust the gas gravity (G) and other properties accordingly.