With HDD becoming a mature methodology, various groups from many origins have come to similar conclusions -- that some form of industry-wide standard guidelines would mitigate HDD damages and accidents, according to Rich Maxwell.



The past two years have seen many new initiatives that impact horizontal directional drilling (HDD). With HDD becoming a mature methodology, associations, government agencies and legislative groups from many origins have come to similar conclusions - that some form of industry-wide standard guidelines would mitigate HDD damages and accidents. Almost in the same breath, most initiatives call for a standardized training curriculum.

In December 2000 during back-to-back round table discussions, I had the opportunity to moderate several contractor, engineer and owner all-day sessions that add-ressed third-party damages and directional drilling. What follows is a compilation of the cream of the crop - the best practices for HDD damage prevention.

Just as a curriculum for directional drilling often is divided into pre-construction, construction and post-construction sections, our purposes here are best served by such an outline.

Pre-construction

• Design realistic placement.
  
• Address the actual depth of existing infrastructure.
  
• Soil formation information/core samples should be provided.
  
• Engineers should use computer based bore-planners.

Bid Preparation

• Owners should select qualified HDD contractors.
  
• Fast-track start and completion deadlines should be shamed.
  
• Empower right -of-way gatekeepers to make and enforce placement standards.
  
• Bid documents should address actual length of bore and wireline locate tools.
  
• For possible electronic interference, itemize wireless locating equipment.

Use the One-call System

• Avoid bundled call requests.
  
• Call on off-peak days.
  
• Only request actual work.
  
• White line the bore path.
  
• Refresh tickets.
  
• Coordinate regular meetings with excavators, owners and locators.
  
• Promote full participation from all utilities in one-call system.

Site Investigation and Evaluation

• Employ high-tech locating technology such as Ground Penetrating Radar (GPR) and acoustic in underground survey.
  
• Request sewer lateral maps from the water company.
  
• Open manholes to determine direction of lines and verify depths.
  
• Familiarize crews with signs of utility placement (pedestals, manholes, tie-in boxes, private lighting).

Planning of Excavation

• Include a permanent method of locating when installing for future excavation.
  
• Mark and plot bore path, entry and exit points.
  
• Mentally plot side-view of entire bore path.
  
• Avoid exiting at congested pedestal/pole locations ("spider holes").

Drilling Operation

• Respect safety zones vertically and horizontally.
  
• Anticipate back-reamer diameter during pilot bore.
  
• Understand "deflection", "drill string straightening" and soil behavior.
  
• Report all hits, nicks and scratches
  
• Pay attention to atypical sounds and resistance.
  
• Inspectors should be trained and read drill head locator systems.

Post-construction

• Participate in local utility coordinating committees.
  
• Remember that HDD is not always the best way - protect the reputation of HDD.
  
• Attend refresher classes and cross-train on how other utilities are installed.
  
• Provide HDD training geared at inspectors and design engineers.

Drilling Safety Rules

• At all times, know where your drill head is and where existing underground facilities are located.