Type 3

Pipe bedded in 4 inches minimum loose soil. Backfill lightly consolidated to the top of pipe.

Type 4

Pipe bedded in sand, gravel, or crushed stone to depth of 1/8 pipe diameter, 4 inches minimum. Backfill compacted to top of pipe.

Type 5

Pipe bedded in compacted granular material to the center line of pipe, 4 inches minimum under pipe. Compacted granular or select material to top of pipe.