A pilot bore is drilled to a designed path using a steerable head tracked from the surface, then reamed to the required diameter. A pre-fused pipe, typically HDPE, is then pulled back through in a single continuous pull. For polyethylene pipe, the design, pullback load calculations, and installation procedures are covered by ASTM F1962. Equipment is generally classed mini, midi, or maxi-HDD depending on the drill's length and diameter.
HDD is used across water, sewer force main, gas, and telecom or fiber installation: anywhere a utility owner needs to avoid surface disruption over a defined crossing, whether that is a highway, a river, or protected wetlands. Crossing length, pipe material, and diameter drive most of the cost on an HDD bid. That scope is typically buried across the drawings and a spec section rather than called out in one place. Nonlinear extracts it when it reads a bid package.
