Excavations and trenches are categorised as follows:
- S1.5.1
- Large diameter core – a core over 150 mm in diameter.
- S1.5.2
- Micro trench – an opening up to 60 mm wide and over 1 m long.
- S1.5.3
- Narrow trench – an opening over 60 mm and up to 300 mm wide and over 1 m long.
- S1.5.4
- Small openings – an excavation that is none of the above, with a reinstatement surface area, excluding the apparatus surface area, up to:
- 2 m2 in road types 0, 1 and 2; or
- 4 m2 in road types 3 and 4 and in footways, footpaths and cycle tracks.
- S1.5.5
- Other openings – any excavation or trench that is none of the above (S1.5.1 to S1.5.4).
- S1.5.6
- Deep opening – any of the above (S1.5.1 to S1.5.5) where the depth of cover over apparatus is greater than 1.5 m but not including openings with a depth of cover intermittently greater than 1.5 m over lengths of less than 5 m.
