To determine the longest length for systems operating over 2 psig, what must be added?

The longest length of a gas piping system operating over 2 psig is determined by considering the equivalent length of each fitting, bend, or valve in the system. This is essential because fittings and bends introduce resistance to gas flow, which can affect the overall performance of the system.

When calculating the total length of the piping, each fitting, valve, or bend is assigned an equivalent length based on how much resistance it adds. This equivalent length is typically represented as a straight pipe equivalent, allowing for an accurate representation of how each component impacts the flow.

Adding the equivalent lengths ensures that the design accounts for all the additional resistance in the system, providing a more accurate picture of the total effective length of the piping. This allows technicians to assess whether the system will operate efficiently under the given pressure and flow conditions.

In contrast, other factors like the diameter of the pipe, weight of the gas, or height of the installation may also be essential for various calculations, but they do not directly contribute to determining the longest effective length of the piping system in terms of the flow resistance described. Therefore, focusing on the equivalent lengths of fittings and other components is crucial for proper piping design and ensuring safety and efficiency in gas installations operating at higher pressures.