introduction concrete pipe Recommended Manhole Sizing for Angular Connections To determine the recommended large diameter manhole to meet your project requirements, please utilize the Manhole Sizing Calculator located on the Lafarge Pipe website (here). This spreadsheet based calculator will provide a recommended manhole diameter based on the required inputs of two entry pipe sizes and the angle between openings. For concrete openings, the calculations performed consider the opening size to be equal to 100 mm greater than the outer diameter of a C-Wall concrete pipe, as identified in the Maximum Recommended Opening Sizes table opposite. If there are multiple pipe openings, please enter information for the two that are in closest proximity. Please check the recommended manhole size against your local municipal specifications, which will supersede the manufacturing capabilities denoted. Pipe 1 Angle stormwater treatment technologies Pipe 2 box sections Large Diameter Manholes Joints As with concrete pipe, large diameter manhole joints consist of a spigot and bell connection. Manhole gaskets are provided/available for all diameters sold; however, it should be noted that any openings installed in the manhole that interfere/cross the manhole joint eliminate the effectiveness of the gasket and alternate sealing methods will need to be considered if water tightness is of concern. manhole and catch basin material LAFARGE PIPE eMANUAL PAGE 45