TYPE 1
- Flat-bottom trench
- Loose backfill
TYPE 2
- Flat-bottom trench
- Backfill lightly consolidated to centre-line of pipe.
TYPE 3
- Pipe bedded in 4-inch loose soil
- Backfill lightly consolidated to top of pipe
TYPE 4
- Pipe bedded in sand, gravel or crushed stone to depth of 1/8 pipe diameter, 4-inch minimum
- Back-fill compacted to top of pipee
TYPE 5
- Pipe bedded in compacted granular material to centreline of pipe
- Compacted granular or select material to top of pipe
- “Flat-bottom” is defined as undisturbed earth
- “Loose soil” or “Select” is defined as native soil excavated from the trench, free of rocks, foreign materials and frozen earth