These fill height tables show the required class of pipe necessary for a particular fill height for each diameter of pipe based upon the indirect design method. The HS20 Live Load tables have been prepared assuming a soil weight of 120 lbs/ft., AASHTO HS20 live load includes impact factors, rigid pavement over the pipe, and installation in an embankment condition. Heavy construction or compaction equipment loads that occur with low cover heights over the pipe can be much more severe than the design loads included in these fill height tables. If these loads occur a special design should be made to evaluate whether the pipe class is sufficient to handle these loads.

Installation types 1, 2, 3 and 4 are the Standard Installations detailed in ASTM C1479 and in AASHTO Bridge Requirements.

Hardie® Pipe is designed and installed in the same manner as any concrete pipe. If other installations are used, designs appropriate for those installations should be run.

NOTE: For fill heights less than 12 inches, please consult Hardie® Pipe Customer Service.