QUESTION

The chart on dwg. S1 for manhole diameters, was that assuming straight through lines or does it cover all cases e.g. manholes with multiple inlets?

COMMENT

The S1 table is a guide for one inlet pipe and one outlet pipe at a similar elevation. The Shaw Precast guide below is a good guide but I would still suggest the designer to rely on basic engineering principal when sizing manhole because there are situations you need to choose a smaller manhole when the inlet pipe is higher than the outlet pipe, or choose a bigger a manhole when there are multiple smaller pipes coming in at similar elevations.