All fixed features, such as edgings, channel blocks, drainage fixtures, surface boxes and ironware etc., should be as level and flush as possible with the adjacent surfaces and must be installed to the following level criteria:
Fixed features must be laid to coincide with the mean level of immediately adjacent surfaces.
The construction tolerance between the level of the fixed feature (excluding drainage features) and immediately adjacent surfaces is ± 6 mm.
Drainage features must be installed flush with or up to 6 mm below the level of the adjacent surface.
At pedestrian crossing points where the kerb is flush with the carriageway, the kerb must be re-laid flush with, or not more than 6 mm above, the carriageway.