The LP Gas Pipe Sizing Calculator assists in calculating the appropriate diameter for gas pipes in a system. This tool is particularly useful in preventing problems such as insufficient gas flow to appliances, which can affect their performance and safety. By inputting the required flow rate and the length of the pipe run, along with other necessary parameters, the calculator provides a precise pipe diameter recommendation.
Formula of LP Gas Pipe Sizing Calculator
The formula used by the LP Gas Pipe Sizing Calculator is rooted in the principles of fluid dynamics. It considers factors such as the length of the pipe, the flow rate of the gas, and the pressure drop across the pipe system.
General Formula:
Q = (354.6 * C * (P1^2 - P2^2)) / (L * (SG)^0.5)
Here,
- Q = Flow rate of gas (cubic feet per hour, CFH)
- C = Flow coefficient (depends on the pipe material and size)
- P1 = Initial pressure (psia)
- P2 = Final pressure (psia)
- L = Length of the pipe (feet)
- SG = Specific gravity of the gas (relative to air)
For practical applications, especially when dealing with LP gas which typically has a specific gravity of 1.52, a simplified version of the formula is often used:
d = (0.607 * Q * L) / (P1 - P2)
Here,
- d = Diameter of the pipe (inches)
- P1 = Initial pressure (inches of water column or psig)
- P2 = Final pressure (inches of water column or psig)
Table for General Terms
| Term | Description | Example Conversion |
|---|---|---|
| CFH | Cubic Feet per Hour | Measure of gas flow rate |
| psig | Pounds per Square Inch Gauge | Unit of pressure; 14.7 psig = 1 atm at sea level |
| d | Diameter of the pipe | Inches; calculated from the formula |
| L | Length of the pipe | Feet; total length from source to endpoint |
| SG | Specific Gravity | Relative density compared to air (SG of air = 1.0) |
| Q | Flow rate of gas | Used in the formula to determine other parameters |
Example of LP Gas Pipe Sizing Calculator
Consider a scenario where you need to calculate the pipe size for an LP gas system with a flow rate of 100 CFH, a total pipe length of 50 feet, an initial pressure of 10 psig, and a final pressure of 5 psig. Using the simplified formula:
d = (0.607 * 100 * 50) / (10 - 5) = 607 inches
This result can then be converted into a more practical unit, and the appropriate pipe diameter can be chosen based on standard pipe sizes available.
Most Common FAQs
A1: The most critical factor is the flow rate of the gas, as it determines the pipe diameter required to ensure adequate gas reaches the appliances without significant pressure loss.
A2: Longer pipes require larger diameters to minimize the pressure drop over the distance. This ensures that gas flows efficiently from the source to the point of use.