The Ohio Department of Transportation (ODOT) is reviewing a draft of a proposed Standard Specification for Horizontal Directional Drilling which would ensure quality trenchless installations of underground pipelines and conduits.
The standard was developed by Bowling Green State University (BGSU) for the ODOT Office of Transportation and Research in cooperation with ODOT and the U.S. Department of Transportation Federal Highway Administration with assistance by the Ohio Directional Drilling Association (OHDDA).
“The ultimate objective of the research project and the proposed HDD standard was to develop a balanced HDD specification that will benefit all parties involved in directional drilling,” said Alan Atalah, Ph.D., of the BGSU department of construction management who, along with Sandria Brown, are authors of the proposed standard.
“Of course,” Atalah added, “we hope that the standard will be implemented.”
What happens next is up to ODOT. “We hope that the department will gather input from the larger industry constituents and other departments within ODOT to make improvements, if needed,” said Atalah. “Next would be to test the standard on one or two projects, update accordingly, then implement it as part of the book of specifications. It is hoped that other DOTs also will adopt it. It is expected that the Great Lakes Trenchless Association (GLTA) will slightly modify the standard to suit the purpose of its members and use it in the Great Lakes region.” (In 2013, the Ohio Horizontal Directional Drilling Association is making the transition to the Great Lakes Trenchless Association.)
The GLTA had been discussing various research initiatives in the past and developing a standardized specification for the HDD industry has been a top priority for some time, said Brian Willis, GLTA president.
“As an association, our primary goal is to bring multiple organizations and stakeholders together in order to work collaboratively on projects that will benefit the trenchless industry,” he continued. “The specification project is a great example of a multitude of stakeholders coming together in order to address a problem and provide sustainable solutions that will benefit the HDD industry and promote trenchless technology to decision makers.” Willis is project manager/estimator at Precision Directional Boring LLC, Valley City, OH.
The BGSU research team collected existing HDD specifications from various municipalities and agencies in Ohio and other states.
The team then compared and identified major areas of agreement and disagreement among these HDD specifications. The agreed-upon issues in the HDD specifications were used as the foundation for the proposed specifications. The issues of disagreement were analyzed and evaluated for inclusion in the specifications. These major areas of agreement/disagreement were then compared against the HDD Good Practices Guidelines manual to narrow down the list of points of disagreement for further research.
The specification committee also reviewed HDD related publications by other DOTs and more in addition to the above cited specifications in developing the specifications. Below is a brief summary of what these collected specifications cover.
Drill Rig — The standard describes the basic components necessary for a drill rig to ensure it has sufficient capabilities to successfully drill the pilot hole and pull back the product pipe effectively and safely. Its hydraulic system must be free of leaks. The machine must be anchored to the ground during drilling and pullback operations. It must have a system to detect and issue an alarm if the drill string approaches electric lines and to provide protection against electrocution.
Guidance System — An electronic walkover tracking system or a magnetic guidance system (MGS) probe or proven gyroscopic probe and interface shall be used to provide a continuous and accurate determination of the location of the drill head during the drilling operation. The system must be remotely steerable and permit electronic monitoring of the drill bit’s depth and location. The system must be able to steer the pipe accurately to a window of two inches.
Personnel operating the guidance system must be trained and experienced in its use. When using a magnetic system, the operator must be aware of any magnetic anomalies and shall consider such influences.
Drilling Fluids — Specifications require drilling fluid to be made with clean water and that additives are environmentally safe and approved for use in drilling fluids. Water and additives must be thoroughly mixed. The mixing system shall continually agitate the fluid during boring operations. Boring fluid shall be maintained at a viscosity sufficient to suspend cuttings and maintain the integrity of walls of the bore wall. Fluids must be contained and disposed of in accordance with state/federal regulations and permit conditions with no environmental risk.
Operations/Procedures/Execution — The 10 specifications have sections titled operations/procedures/execution which cover:
- Site preparation and pre-construction survey;
- Drill path survey — the entire drill path shall be accurately surveyed with entry and exit stakes placed in the appropriate locations within the areas indicated on drawings;
- Location of utilities — the majority of the specs require the contractor to notify all companies with underground utilities in the work area via the state or local one-call agency to obtain utility locates and verify locations;
- Pipe handling;
- Pilot hole — the pilot hole shall be drilled along the bore path as specified to tolerances for entry point location, elevation, limitations on depth, alignment, curve radius and exit point location;
- Reaming and pull back; and
- Testing installed pipe — the majority of specifications require pressure and leakage testing, and five specs require hydro-testing.
Site Restoration — Four specifications have a section titled site restoration, most requiring that following the drilling operations, the contractor shall demobilize equipment and restore the work site to original condition or better. Restoration shall include paved and unpaved surfaces, shrubbery, landscaping, trees, structures and all else encountered. Any noticeable surface defects, due to the drilling operation, shall be repaired. All excavations will be backfilled and compacted according to the project’s specifications.
Submittal — Seven specifications mandate that the contractor submit a work plan. Six specifications have a qualifications and personnel section; four specifications direct the contractor to submit shop drawings. Three out of the 10 specifications have material, product data and equipment section; two specifications have a record drawings and closeout section. One specification has the following sections that require submittal of a manufacturer’s certification that products meet or exceed specified requirements; the bore plan; production and as-built drawings; testing, quality control and assurance documentation; supplemental work plan requirements; and construction records.
Drafting the specification
Research and preparation of the standard was a detailed and time-consuming task. The committee’s first meeting was on March 2, 2011. The proposed standard was submitted to the ODOT on Nov. 6, 2012 and approved after modifications on Jan. 28, 2013.
“One of the early struggles with developing specifications for HDD is the wide range of applications in which the HDD technology is used and the different levels of challenges and risks,” states the report. “The specification committee agreed that creating one specification that addresses these challenges and risks is unwise. A separate specification should address the challenges and risks associated with the [maxi] horizontal drilling installations which can be several thousand feet in length and larger in diameter than 24 inches . . . [This specification] was developed for pipes in the range of four inches to 24-inches for pressurized applications. Therefore, Maxi HDD and smaller than four-inch installations are outside the scope of the proposed specifications. Also, HDD installations for gravity applications are excluded from the scope of these specifications.”
Atalah said that, as with any research project, there were ups and downs.
“Changing personnel (ODOT) close to the end of the project provided a little bit of challenge,” he continued. “The wide variations of the HDD projects in terms of complexity and sensitivity to business environments make it difficult to come up with specification that is supposed to be specific, but the specifics may not be workable across the board for all kinds of HDD projects. Balancing the interests of the different interest groups was also challenging.”
The plan for implementing the proposed standard outlines the following steps:
• Internal review within ODOT to ensure it does not conflict with other ODOT specifications;
• Work with the Great Lakes Trenchless Association to evaluate the proposed specification through an actual HDD project and make adjustments as needed based on the actual application;
• Allow the larger different interest groups across the state of Ohio (engineers, general contractors, HDD contractors, suppliers and other stakeholders) to review the proposed specification to ensure it is balanced and beneficial to the Ohio tax payer: and
• Make updates and adjustments as necessary.