7.12 Vertical Position
AHD level values must be determined at the following points:
- all inlet and outlet pipe inverts, including inlets and outlets associated with junction chambers and branch connections
- pipe invert at the end of any stubs
- pipe invert at start and end of constructed pipeline
- pipe invert at tangent points of curved pipes
- pipe invert at changes in grade
- pipe invert at start and end point of transitions
- manhole covers and grated inlets (mean height if not positioned horizontally)
- top of headwalls
- apron of inlet/outlet structures where there is a significant difference to pipe invert (say, greater than 0.15 metres).
Invert levels are to be annotated on the longitudinal section, structural details and Detail design alignment plan where deemed necessary, with cover levels being annotated on structural details and longitudinal section.
