When using the longest-length (longest-run) method to size a gas piping system, which length is used to select pipe size for every section?

Explanation

In the longest-length method you find the total developed length from the gas source to the farthest outlet, then use that single length column in the table to size every section based on its own cfh demand. Using the most remote run assures adequate pressure everywhere in the system. Add equivalent lengths for fittings where the code or table requires it.