Standard Practice for Subsurface Installation of Corrugated Polyethylene Pipe for Agricultural Drainage or Water Table Control

This practice covers the procedures for subsurface installation of corrugated polyethylene pipe, in accordance with the flexible conduit principles, intended for agricultural drainage or water table control. It is not however recommended for sanitary and storm sewer applications. General requirements for installation include: maximum and minimum burial depth; trench width; design of blinding, bedding, or envelope materials that are to be placed as the pipe is installed to ensure uniform continuous support; and granular or synthetic filters that are used to restrict the movement of particles into the pipe so as to maintain its hydraulic capacity. The pipe shall be aligned as smooth as possible with a curve radius larger than five times the pipe diameter while the backfill material shall be placed preferably on an angle to prevent pipe displacement or deflection. Stony trenches shall be avoided and any over-excavation or rock excavation shall be treated with proper bedding material. Factors that affect the proper handling of the pipe such as temperature; stretch caused by tension and bending forces; synthetic envelopes and filters that are subject to abrasion and tearing; and protection from fire hazards, livestock, heavy wheel traffic, and rodents or other animals shall also be considered during installation.