Can you explain the process of sizing gas lines for long-distance or high-volume applications?

Sample interview questions: Can you explain the process of sizing gas lines for long-distance or high-volume applications?

Sample answer:

Process of Sizing Gas Lines for Long-Distance or High-Volume Applications:

1. Determine Gas Demand: Calculate the maximum hourly gas consumption (CFH) for all appliances powered by the gas line.

2. Choose the Pipe Material: Select a gas pipe material suitable for the application, such as polyethylene (PE), steel, or copper.

3. Calculate the Pressure Drop: Determine the allowable pressure drop based on the appliance manufacturer’s specifications and code requirements.

4. Estimate Pipeline Length: Measure the total length of the gas line from the source to the end point.

5. Select the Pipe Diameter: Use the following formula to calculate the required pipe diameter (in inches):

Pipe Diameter = √(Q * (Lw + Ln) * F * 1.54 / (P1² - P2²))

where:

• Q = gas demand (CFH)
• Lw = equivalent length for fittings and valves (feet)
• Ln = length of the gas line (feet)
• F = friction factor (depends on pipe material and flow rate)
• P1 = inlet pressure (psi)

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