Attachment_3_-_Supplemental_Specifications.pdf

Supplemental Specification - Horizontal Directional Drilling

PART 1 GENERAL

1.1 DESCRIPTION

The work specified in this section consists of furnishing and installing underground utilities using the horizontal directional drilling (HDD) method of installation, also commonly referred to as directional boring or guided horizontal boring.

1.2 Materials

High Density Polyethylene, SDR-9, 200 PSI pressure-rating piping shall be used as basis of design.

1.3 QUALITY ASSURANCE

The requirements set forth in this document specify a wide range of procedural precautions necessary to insure that the very basic, essential aspects of a proper directional bore installation are adequately controlled. Adherence to the specifications contained herein, or the Contracting Officer's (CO) approval of any aspect of any directional bore operation covered by this Specification, shall in no way relieve the Contractor of their ultimate responsibility for the satisfactory completion of the work authorized under the Contract.

1.4 SUBMITTALS

A. Work Plan:

Prior to beginning work, the Contractor must submit to the Contracting Officer's Representative ( COR), a general work plan outlining the procedure and schedule to be used to execute the project. Plan should document the thoughtful planning of equipment, materials and personnel required to successfully complete the project.

B. Equipment:

Contractor will submit specifications on directional drilling equipment and materials to be used to ensure that the equipment will be adequate to complete the project.

C. Boring Plan:

Prior to beginning work the Contractor must submit to the COR a Boring Plan. The Boring Plan shall include the length of rods, distance from the drilling machine, drilling fluid specifications, depth below grade and horizontal and vertical orientation in tabular format. A sketch of the bore path, including pit depths and dimensions, shall also be provided.

D. As-Built Record:

The Contractor shall submit a plan, profile and tabular record of the position of the HDPE supply line. The record data shall be similar to that shown on the boring plan.

PART 2 PRODUCTS

2.1 EQUIPMENT

The directional drilling equipment shall consist of a directional drilling rig of sufficient capacity to perform the bore and pullback the pipe, a drilling fluid mixing and delivery system of sufficient capacity to successfully complete the crossing, a guidance system to accurately guide boring operations and trained, competent personnel to operate the system. All equipment shall be in good, safe operating condition with sufficient supplies, materials and spare parts on hand to maintain the system in good working order for the duration of this project.

2.2 DRILLING SYSTEM

A. Drilling Rig:

The directional drilling machine shall consist of a hydraulically-powered system to rotate, push and pull hollow drill pipe into the ground at a variable angle while delivering pressurized fluid mixture to a guidable drill (bore) head. The machine shall be anchored to the ground to withstand the pulling, pushing and rotating pressure required to complete the crossing. The hydraulic power system shall be self-contained with sufficient pressure and volume to power drilling operations. Hydraulic system shall be free of leaks. Rig shall have a system to monitor and record maximum pull-back pressure during pull-back operations.

B. Drill Head:

The drill head shall be steerable by changing its rotation and shall provide the necessary cutting surfaces and drilling fluid jets.

C. Mud Motors (if required):

Mud motors shall be of adequate power to turn the required drilling tools.

D. Drill Pipe:

Shall be constructed of high-quality 4130 seamless tubing, grade D or better, with threaded box and pins. Tool joints should be hardened to 32-36 RC.

2.3 GUIDANCE SYSTEM

The Guidance System shall be of a proven type and shall be set up and operated by personnel trained and experienced with this system. The Operator shall be aware of any magnetic anomalies and shall consider such influences in the operation of the guidance system if using a magnetic system.

2.4 DRILLING FLUID (MUD) SYSTEM

A. A self-contained, closed, drilling fluid mixing system shall be of sufficient size to mix and deliver drilling fluid composed of bentonite clay, potable water and appropriate additives. Mixing system shall be able to molecularly shear individual bentonite particles from the dry power to avoid clumping and ensure thorough mixing. The drilling fluid reservoir tank shall be sized for adequate storage of the mud. Mixing system shall continually agitate the drilling fluid during drilling operations.

B. Drilling Fluids:

Drilling fluid shall be composed of clean water, bentonite, and appropriate additive(s).

Water shall comply with mixing requirements set forth by the additive(s) manufacturer(s). The water and additive(s) shall be mixed thoroughly and be absent of any clumps or clods. No hazardous additives may be used. Drilling fluid shall be maintained at a viscosity sufficient to suspend cuttings and maintain the integrity of bore wall.

C. Delivery System:

The mud pumping system shall have a minimum capacity to supply mud in accordance with the drilling equipment pull-back rating at a constant required pressure. The delivery system shall have filters in-line to prevent solids from being pumped into the drill pipe. Connections between the pump and drill pipe shall be relatively leak-free.

Used drilling fluid and drilling fluid spilled during drilling operations shall be contained and properly disposed of. Pumps and or vacuum truck(s) of sufficient size shall be in place to convey excess drilling fluid from containment areas to Storage facilities.

PART 3 EXECUTION

3.1 GENERAL

The Contracting Officer's Representative (COR) must be notified 48 hours in advance of starting work. The directional bore shall not begin until the COR is present at the job site and agrees that proper preparations for the operation have been made. The COR’s approval for beginning the installation shall in no way relive the Contractor of the ultimate responsibility for the satisfactory completion of the work as authorized under the Contract.

3.2 PERSONNEL REQUIREMENTS

A. Use only experienced installers, equipment operators, supervisors and engineer designers. Contractor's experience shall include:

1) At least one project requiring side and compound bends, and

2) At least two water crossings.

B. Security Requirements:

Not Used

3.3 DRILLING P RO CEDU RE

A. Site Preparation:

1) Worksite as indicated on drawings, with right-of-way, shall be graded or filled to provide a level working area. No alterations beyond what is required for operations are to be made. Contractor shall confine all activities to designated work areas.

B. Drill Path Survey:

Entire drill path shall be accurately staked on the ground, with entry and exit stakes placed in the appropriate locations within the areas indicated on drawings.

If Contractor is using a magnetic guidance system, drill path will be surveyed for any surface geomagnetic variations or anomalies.

C. Safety:

Contractor shall adhere to all applicable state, federal and local safety regulations and all operations shall be conducted in a safe manner.

D. Pipe:

Pipe shall be heat welded/fused together in one length, if space permits.

E. Pilot Hole:

1) Pilot hole shall be drilled on bore path with no deviations greater than 5% of depth per a length of 100 '. In the event that pilot does deviate from bore path more than 5% of depth in 100', Contractor will notify the COR and the COR may require Contractor to pull-back and re-drill from the location along bore path before the deviation.

F. Reaming:

Upon successful completion of pilot hole, Contractor will ream bore hole to a minimum of 25% greater than outside diameter of pipe using the appropriate tools. Contractor shall not attempt to ream at one time more than the drilling equipment and mud system are designed to safely handle.

G. Pull-Back:

1) After successfully reaming borehole to the required diameter, Contractor will pull the pipe through the borehole. In front of the pipe will be a swivel. Once pull-back operations have commenced, operations must continue without interruption until pipe is completely pulled into bore hole. During pull-back operations Contractor shall not apply more than the maximum safe pipe pull pressure at any time.

2) In the event that pipe becomes stuck, Contractor will cease pulling operations to allow any potential hydro-lock to subside and will commence pulling operations. If pipe remains stuck, Contractor shall notify the COR. The Contractor shall not be relieved of his responsibility to satisfactory complete the work as authorized under the Contract if a stuck pipe cannot be pulled.

If all other pipe pulling and/or boring methods fail, the CO may direct the Contractor to complete the pipe installation using open cut methods. The Contractor shall install the pipe using open cut methods and restore all areas disturbed by open cutting the pipe trench at no additional cost to the Owner.

H. Environmental Controls:

1) Contractor shall take all necessary precautions to control and contain all debris in the immediate work area and clean up any and all dust and debris as soon as possible at all times.

END OF SECTION

Supplemental Specification - Horizontal Directional Drilling