scope:

These guidelines describe the design, selection considerations, and installation procedures for the placement of polyethylene (PE) pipe belowground using mini-horizontal directional drilling (mini-HDD) equipment. The primary focus of this document is on pipe constructed of high density polyethylene (HDPE) with a material designation code of PE4710, for municipal applications, including potable water and sewers. For convenience, the term "HDPE" is used as a generic term to refer to the PE4710 material. Related properties for this material are provided in the "Plastics Pipe Institute Handbook of Polyethylene Pipe".(1)¹ The pipe may be supplied in continuous lengths on a reel or discrete segments assembled together, typically by fusion, in the required length.

Horizontal directional drilling (HDD) represents a form of trenchless technology. The equipment and procedures are intended to minimize above and below ground surface damage, restoration requirements, and disruption to traffic, with little or no interruption of existing services. Mini-horizontal directional drilling (mini-HDD), also know as "guided boring", is typically used for the relatively shorter distances, shallower depths, and smaller diameter pipes associated with local distribution lines, in comparison to maxi-horizontal directional drilling (maxi-HDD), typically used for longer distances, greater depths, and larger diameter pipes, such as major river crossings. ASTM F1962 provides detailed information and guidelines for the placement of polyethylene pipe using maxi-HDD technology.

In contrast to ASTM F1962, from which the present guidelines are partially derived (see Section 7 and Appendices B and C), the present document is intended to provide useful information for the less sophisticated, and less well-controlled, mini-HDD technologies and installations, as reflected in the planning and design practices. Thus, mini-HDD warrants more simplified analysis, and correspondingly more conservative assumptions, than used in ASTM F1962. The objective is to provide an outline and brief description of proper procedures to be followed for mini-HDD operations, with reference to existing industry standards and guides that provide greater detail, as appropriate. However, it is also the intention of this document to provide useful details for specific aspects that may not be conveniently available in other sources. Examples of the latter include drill rig setup information, such as setback distances, as a function of drill rod characteristics and rig setup parameters, as well as a simple methodology for selecting the strength (wall thickness) of HDPE pipe as a function of route geometry.

For convenience, the dimensions and other quantities are provided in the customary inch-foot-pound units.

¹The boldface numbers in parentheses refer to the list of references at the end of this document.