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