Engineering guidance on Horizontal Directional Drilling and open-cut pipeline construction — written by the team behind the Pipeline Planning Toolbox.
An engineering overview of Horizontal Directional Drilling (HDD): how the pilot bore, reaming, and pullback phases work, where the method excels, and its practical limitations.
How to lay out an HDD bore profile that can actually be drilled and pulled: entry and exit angle ranges, minimum bend radius rules, depth of cover selection, and tangent placement.
A breakdown of the forces acting on a pipeline during HDD pullback — friction, fluidic drag, capstan effect, and buoyancy — and the PRCI and ASTM F1962 calculation methods.
A tour of the equipment that makes up a maxi-HDD spread — the drilling rig, drill pipe and bottom-hole assembly, mud pumps and recycling system, and the pull-section support gear — and how thrust and torque ratings are matched to a crossing.
A step-by-step walkthrough of conventional cross-country pipeline construction — clearing, grading, trenching, stringing, welding, coating, lowering-in, backfill, testing, and restoration.
How burial depth is set by 49 CFR 192 and 195, why crossings and ditches demand more cover, how bedding and padding protect the pipe and coating, why trenches below the water table must be dewatered with well point systems, and what OSHA requires of the trench itself.
How FEMA flood hazard zones shape pipeline routing and design — why buried crossings must be set below the design-flood scour depth, how aboveground facilities are elevated or floodproofed, when a floodplain development permit and No-Rise certification are required, and how flood-zone map data is screened before a route is set.
Why a pipeline that crosses or parallels a federal levee triggers USACE Section 408 permission — how leveed areas, embankments, and the National Levee Database drive stand-off distances, HDD depth beneath the levee prism, penetration and seepage controls, and a review schedule that must be planned around, not discovered.
How wetlands govern pipeline routing, construction methods, and permitting — what a Clean Water Act Section 404 permit requires, how wetland delineation and Cowardin classification work, why HDD and timber mats are used to cross them, and how National Wetlands Inventory map data is screened before a route is set.
How streams and rivers govern pipeline crossing method and permitting — the difference between Section 404 and Rivers and Harbors Act Section 10, when to use HDD versus open-cut, dam-and-pump, or flume, why scour and bathymetry set the depth, and how hydrography map data is screened before a route is set.
How threatened and endangered species drive pipeline routing, construction timing, and permitting — what ESA Section 7 consultation requires, how critical habitat and migratory-bird rules impose seasonal work windows, why wild and scenic rivers and protected lands add constraints, and how habitat map data is screened before a route is set.
How contaminated sites along a corridor change pipeline routing, excavation, and worker safety — why Superfund, RCRA, and brownfield properties create CERCLA liability and contaminated-soil and groundwater handling problems, how dewatering and spoil disposal are affected, and how contaminated-site map data is screened before a route is set.
Design pressure, MAOP, and MOP are three of the most confused terms in pipeline engineering. This article defines each, gives the Barlow-based design-pressure formula, explains why MAOP is the lowest of several limits, and works a numerical example for an API 5L X52 line.