Minimum Trench Width Calculation in the US for Various Pipe Materials
How to Calculate the Minimum Trench Width for PVC Pipes?
The table below presents the method to compute the minimum trench width for polyvinyl chloride (PVC) pipe installation using the open cut method.
Minimum Trench Width Calculation Formula Based on Pipe Outside Diameter (OD)


Minimum trench width shall be not less than the greater of either the pipe outside diameter plus 16 in (400 mm) or the pipe outside diameter times 1.25, plus 12 in (300 mm):
Wmin = Pipe OD + 16 in
OR
Wmin = 1.25 x Pipe OD + 12 in
