Design for Execution
How Constructability Drives Safer, More Cost-Effective HDD Projects
Written by Thomas Wirbicki
Horizontal directional drilling (HDD) projects are often treated as a design exercise, focused on geometry, calculations, and compliance. However, project success is not determined on paper; it is determined in the field during execution. Designs that cannot be safely and efficiently constructed introduce additional risk, drive unnecessary cost, and reduce control during execution.
HDD designs can frequently demonstrate the consequences of overlooking constructability. In one case, a third-party design had advanced to Issue for Construction (IFC) status, but introduced significant safety risks, excessive equipment requirements, and avoidable cost exposure.
Through a targeted design review and redesign, these issues were addressed, resulting in improved constructability, reduced risk, and substantial cost savings. Integrating field experience, constructability awareness, and lifecycle thinking into HDD design leads to safer execution, stronger outcomes, and measurable cost savings.
Identify Constructability Risks Before Construction Begins
A fully developed HDD design had reached IFC status before undergoing a detailed review. While it had been approved by a Professional Engineer, LSC’s evaluation identified approximately 100 issues that directly impacted execution, many already embedded in stamped plans and not apparent to the asset owner.
A crucial problem was identified: the design could not be built as depicted. Just because a hole can be drilled, doesn’t necessarily mean a pipeline can be safely installed in it.
When constructability is not addressed during design, risk is transferred to the field where options are limited and corrections are costly.
Key challenges identified during the review included:
- No margin for drilling tolerance or field variability
- Misalignment between tracking capabilities and required steering decisions
- Insufficient workspace and site access planning
- An unrealistic installation approach requiring excessive pullback support equipment
- Misinterpretation of geotechnical data
- Inaccurate or inconsistent calculations
- Geometry that introduced safety hazards during installation and operations
These conditions reduce control in the field, increase safety concerns, and introduce unnecessary complexity, driving delays, rework, and cost escalation.
Align Design Decisions with Real-World Execution
The redesign focused on one objective: aligning the design with how the project would actually be built.
Terrain and subsurface conditions were reevaluated, and it was determined the increased depth would also lower the risk of inadvertent returns (IR) in this scenario. Tolerances related to the design and 3-joint radius were both increased to provide more flexibility to the drilling contractor.
The installation approach was simplified. Pipe handling strategies were restructured to reduce unsafe practices and reduce unnecessary constraints. The result was a design that could be executed with greater control, lower risk, and improved predictability.
Capture Measurable Improvements Across Cost, Safety, and Execution
The redesign produced the following clear, quantifiable benefits.
Cost Reduction
✓
Eliminated need for cranes and supporting equipment
✓
Reduced overall equipment footprint and operational complexity
✓
Avoided unnecessary construction costs, such as approximately $1.5 million in crane rentals
Safety Improvements
✓
Reduce unsafe pipe handling practices
✓
Reduced exposure to elevated and constrained operations
✓
Improved overall field safety conditions
Execution Efficiency
✓
Simplified installation strategy
✓
Increased contractor flexibility through improved tolerances
✓
Reduced likelihood of delays, rework, or change orders
Build Designs That Perform in the Field
Most engineering teams can complete the required calculations for an HDD crossing, which is an expected capability. The difference lies in whether the design reflects real-world execution.
All projects should take a constructability-focused approach that aligns design decisions with how work is actually executed in the field. This includes grounding decisions in field conditions, understanding contractor capabilities, building in tolerance for variability, and treating design and construction as a continuous process.
Key differentiators include:
+ Design for construction: Prioritize how the project will actually be built
+ Field-informed decision-making: Apply real-world experience to anticipate execution challenges
+ Built-in tolerance: Account for variability in drilling conditions and performance
+ Cross-phase integration: Align design, procurement, and construction from the start
For project owners, this approach is critical. Issues missed during design often surface during construction, when options are limited and costs are higher. A constructability-focused design reduces these risks upfront.
Deliver HDD Projects with Confidence and Control
HDD project success is determined by execution, not design completion. Designs that fail to account for constructability transfer risk to the field, where it is far more difficult and costly to manage.
By integrating field experience into the design process, project teams can identify risks earlier, simplify installation, and improve control over cost, safety, and schedule.
The result is a design that does more than meet minimum requirements; it performs under real conditions and delivers predictable outcomes.