【国外标准】 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.1.1 This practice is recommended for and limited to gravity flow subsurface drainage systems or water table control, but not recommended for sanitary or storm sewer applications. Procedures are outlined to minimize pipe deflection or structural damage during and after the installation process. These installation procedures are in accordance with “flexible conduit” principles.1.2 This practice applies to all agricultural subsurface drainage or water table control installations using Specification F667, F2648, or other plastic pipe.NOTE 1: Specific references to the appendix in the body of this practice are for informational purposes.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only, may not be equivalents and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.