How to Calculate Pipe Slope & Invert Elevations for Civil Construction This article is Part 1 of the OLH Pipe Grade Series. Pipe grade is more than a calculation. A crew has to understand the slope, build the pipe to the correct elevation, and document what happened during installation. This series follows that progression: Part 1 — Calculate the slope and invert elevations. Part 2 — Set pipe grade in the field. Part 3 — Document the pipe crew’s daily report. Start with the m