Sample interview questions: Can you explain the process of sizing gas lines for low-pressure or low-flow applications?
Sample answer:
Process of Sizing Gas Lines for Low-Pressure or Low-Flow Applications
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Determine the Flow Rate: Calculate the maximum flow rate (CFH) required for all gas-consuming appliances connected to the line. Refer to appliance specifications or use industry standards (e.g., AGA, IAPMO).
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Establish Pressure Drop: Determine the allowable pressure drop along the gas line. Consider the pressure required at the appliances and the available supply pressure. Typically, a pressure drop of 0.5″ w.c. or less is recommended.
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Select Pipe Material: Choose the appropriate pipe material based on the gas type, application, and local codes. Copper, steel, or polyethylene (PE) are common choices for low-pressure lines.
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Calculate Line Diameter: Using pipe sizing tables or hydraulic calculators, determine the nominal pipe diameter that meets the flow rate requirement and pressure drop criteria. Consider using a slightly larger diameter than calculated to provide … Read full answer
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