Ductile Iron Pipe Research Association - DIPRA - Standard Laying Conditions for Ductile Iron Pipe

DUCTILE IRON PIPE

Standard Laying Conditions for Ductile Iron Pipe

Type 1*
Flat-bottom trench.** Loose backfill. Type 2
Flat-bottom trench.** Backfill lightly consolidated to centerline of pipe.

Type 3
Pipe bedded in 4-inch minimum 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. Backfill compacted to top of pipe. (Approximately 80% Standard proctor, AASHTO T-99.)

Type 5
Pipe bedded to its centerline in compacted granular material, 4-inch minimum under pipe. Compacted granular or select material*** to top of pipe. (Approximately 90% Standard Proctor, AASHTO T-99.)

*For 14-inch and larger pipe, consideration should be given to the use of laying conditions other than Type 1.

**"Flat-bottom" is defined as "undisturbed earth."

***"Loose soil" or "select material" is defined as "native soil excavated from the trench, free of rocks, foreign material, and frozen earth."


Type 1* Flat-bottom trench.** Loose backfill.		Type 2 Flat-bottom trench.** Backfill lightly consolidated to centerline of pipe.

Type 3 Pipe bedded in 4-inch minimum 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. Backfill compacted to top of pipe. (Approximately 80% Standard proctor, AASHTO T-99.)

Type 5 Pipe bedded to its centerline in compacted granular material, 4-inch minimum under pipe. Compacted granular or select material*** to top of pipe. (Approximately 90% Standard Proctor, AASHTO T-99.)
For 14-inch and larger pipe, consideration should be given to the use of laying conditions other than Type 1. "Flat-bottom" is defined as "undisturbed earth." **"Loose soil" or "select material" is defined as "native soil excavated from the trench, free of rocks, foreign material, and frozen earth."