9-8. HDD PIPE INSTALLATION SPECIFICATIONS.pdf

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SECTION 02320

HORIZONTAL DIRECTIONALLY DRILLED (HDD) PIPE INSTALLATION

PART 1 -- GENERAL

1.01 THE REQUIREMENT

A. The CONTRACTOR shall furnish all labor, equipment and materials and perform all operations in connection with the complete installation of horizontally directionally drilled (HDD) pipe, as specified herein and as shown on the Drawings. The CONTRACTOR shall be responsible for coordinating work in this Section with related work specified elsewhere in this Contract, so as to provide all hardware and accessories for a complete installation. The CONTRACTOR shall be responsible for accurate alignment of the specified pipe plan and profile and monitoring of the drilling and pull-back operation.

B. All parts of the materials furnished shall be amply designed, manufactured and constructed for the maximum stresses occurring during fabrication, erection and installation. All materials shall be of the very best quality, entirely suitable for the service to which they will be subjected and shall conform to all applicable Sections of these Specifications.

Manufacturer's designs shall accommodate all the requirements of these Specifications.

C. All available and known geotechnical reports, logs, borings, and laboratory testing performed within close proximity of the project corridor have been made available as “technical data” and not part of the Contract Documents. This is provided as information only and solely for the convenience of Bidders. The Owner and/or the Engineer do not warrant or guarantee the accuracy or correctness of this material with respect to actual subsurface conditions. Subsurface conditions are considered unclassified and no expectation of quantity, specific location of ground conditions, or geotechnical baselines are provided or assumed herein.

D. For all excavations and pipe installation techniques defined under this Section, CONTRACTOR shall install pipe using techniques and methods selected by the CONTRACTOR that are appropriate for prevailing ground conditions. CONTRACTOR shall review all available geotechnical reports and data and perform any additional soil investigations he deems necessary, at his own expense, for the planning and the selection of drilling techniques and methods in order to enable proper construction as shown on the Drawings and other requirements of Contract Documents.

E. Where warranted in the experience of the CONTRACTOR or where identified on the Drawings, a conductor casing may be installed as part of the appropriate preparation for directional drilling activities to reduce risk of surface settlement and heaving, protect nearby structures and utilities, and reduce the likelihood of frac-outs. CONTRACTOR shall design and in include in Bid furnishing of all labor, equipment, materials, and supplies necessary for the conductor casing including sizing and method of installation to meet project objectives specified herein.

F. The HDD CONTRACTOR shall perform the work in general conformance with ASTM Standard F1962-20, current revision, “Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe of Conduit under Obstacles, Including River Crossings.”

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1.02 SUBMITTALS

A. The CONTRACTOR shall submit Shop Drawings, Material Certification, and other information as specified for all materials in this Section. Submittals shall include:

1. Qualifications: HDD bore subcontractor’s qualifications and experience as outlined in this Section.

2. Daily Project and Guidance System Logs: Example logs should be provided in the submittals phase, though actual logs shall be submitted on a daily basis during construction. Plot the horizontal and vertical location of the pilot bore at intervals not to exceed 20 feet.

3. Manufacturer’s Data for the pipe materials, MJ adapters/fittings and pipe joining materials proposed for use.

4. Butt Fusion Reports.

5. As-Built Records of Pilot Hole: The directional boring CONTRACTOR shall submit pilot hole as-builts in accordance with the requirements stated herein.

6. As-Built Records of Bore: The directional boring CONTRACTOR shall submit certification, by a Professional Engineer or Professional Surveyor and Mapper licensed in the State of Florida, that the directional boring has been performed in accordance to the construction drawings, and provide signed and sealed certified record drawings of the installation, X, Y, and Z coordinates at maximum 20 feet intervals.

7. Hydrostatic Testing Results

B. Bore Plan: Prior to beginning work, the CONTRACTOR must submit to the Engineer a report of installation procedures, subsurface soil conditions, and water depth as they exist along the path of the proposed installation. The report will ensure that the subsurface conditions are known to the CONTRACTOR and that his proposed crossing procedure is based on factual information. CONTRACTOR should probe soils and/or conduct soil borings along drill path to the extent deemed necessary by CONTRACTOR to provide sufficient information for construction. The report shall include the following:

1. Calculations

a. Calculations shall be submitted to demonstrate that the pipe thickness design is sufficient to meet all design criteria specified. Calculations should demonstrate maximum allowable pulling load on HDPE pipe string.

b. Submit an estimate of the anticipated pullback thrust and load that will be required to install the new pipe. The estimate shall include the calculated buoyant force or weight of the pipe and any proposed method for counter-weighting the pipe during pullback.

c. CONTRACTOR shall submit detailed design calculations for several representative loading conditions for the proposed crossing.

d. All calculations shall be signed and sealed by a Professional Engineer registered in the State of Florida.

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2. Drawings: Submit signed and sealed scaled plan and profile of the proposed bore.

The drawing should include the same horizontal and vertical scale as the Contract Drawing showing the proposed HDD borepath and final pipeline configuration of vertical and horizontal curves including the following characteristics:

a. Location of entry/exit pits

b. Size, footprint, and dimensions of all equipment (including fusion equipment) and other staging areas

c. An estimate of time proposed to complete each bore.

d. The proposed vertical and horizontal clearances between the bored pipe and any existing / proposed conflicting pipes, conduits or obstructions shall exceed the guidance system accuracy by a minimum of 200% of tolerance.

e. Proposed layout and type of erosion and sediment control

f. Location, size, and footprint of mixing equipment

g. Drill entry/exit angles

h. Drill length

i. Depth of proposed cover under each road and obstacle crossing

j. Bore path including pilot and reaming diameters

k. Radiuses of pilot bore

l. Direction of drill

m. The use of conductor barrels (if applicable)

n. Length of extra pipe

o. Length to reach depth of cover (L2)

p. Length traversed at depth (L3)

q. Length to rise from depth of cover (L4)

r. Bending radius at pipe entry

s. Bending radius at pipe exit

3. Frac-out Plan: Submit a detailed “frac-out” or drilling fluid loss plan. The plan shall detail the drilling fluids utilized as well as procedures for identification of drilling fluid loss and drilling fluid clean up where identified along at grade surfaces to especially include surface water bodies and environmentally sensitive areas. The plan shall include the following minimum criteria:

a. All inadvertent returns or spills shall be promptly contained and cleaned up. The Contractor shall immediately notify the Owner of any inadvertent returns or spills and immediately contain and clean up the return or spill.

b. Operational contingency measures as necessary to minimize the likelihood of drilling fluid discharges such as: monitoring and controlling drilling fluid

41105-001: 02320-4 circulation pressures; appropriately sizing and cleaning of the piloted borehole to remove blockages preventing the return circulation of drilling fluids;

restructuring of returns to a controlled area to be separately pumped or vacuumed by truck; and monitoring gauge pressure by logging differential pressure per rod installed to identify potential “plug-offs” where the bore hole formation will eventually be destabilized if not corrected.

c. Drilling and clean-up procedures in the event of a surface fracture to include:

personnel dedicated to monitoring flow patterns and rates to proactively identify lost-circulation, perform periodic inspection of the alignment and communicate findings to supervisor, and/or to control and cleanup; materials and equipment such as a vacuum truck and back-hoe stationed onsite to install silt fencing, hay bales, floating turbidity curtains, and/or temporary pits and berms; stoppage procedures in place for all activities that potentially contribute to the further discharge of drilling fluids; and proper disposal procedures for waste fluids and cuttings from all HDD activities.

4. Equipment: Submit a list of equipment with manufacturer’s literature expected to be used for the directional bore, including special equipment and materials required for various in-situ conditions. To include: drilling rig, mud mixing system, mud motors (if applicable), down-hole tools, separation system, rig safety systems, and HDPE butt fusion equipment. Drill rig information should include thrust and torque capacities.

5. Guidance: Submit locating equipment proposed for use, the method of locating to be used, and the proposed sequence and method of construction for approval by the ENGINEER. Include information on how the bore is to be steered, the information recorded, and the as-built provided. The drilling company shall be responsible for accurate alignment of the specified pipe plan and profile and monitoring of the drilling and pull-back operation to the satisfaction of the Owner.

6. Drilling Plan: Submit a drilling plan which shall include the planned drill bore path, the method for monitoring and controlling speed, line, grade and rate of fluids delivered.

Include sequence, size and description of each reamer and final swabbing of bore path prior to pullback. Plan should include the proposed bore hole size, proposed drilling fluid mix design and composition and MSDS, proposed viscosity, fluid quantities, delivery volume and pressure, method of soil / slurry separation, and proposed pre-ream procedures.

7. Drilling Fluid: Submit detailed technical information, specifications, and MSDS for selected drilling fluids and additives. Submit method of storing, transporting, and disposing of cuttings and drilling fluid. Methods shall not impact waterways or wetlands and shall be in accordance with all regulatory agencies.

8. Pipe Assembly and Staging: Proposed plan for assembling and staging the pipe string prior to and during pullback. Information should include: procedure for assembling pipe, location of proposed assembly area, and fusion equipment, procedure for moving assembled pipe to pullback location. Size, spacing, and locations of pipe stands and/or equipment used to lift staged pipe over obstacles/driveways should also be included.

9. Hydrostatic Testing Plan: Submit testing plan for partially (or fully) assembled pipe strings prior to pull-back and after pull-back.

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10. Schedule: Submit a time schedule for completing each directional bore, including any delays due to particular soil conditions.

11. Staging Area Layout.

1.03 MANUFACTURERS

A. The materials covered by these Specifications are intended to be standard materials of proven reliability and as manufactured by reputable manufacturers having experience in the production of such materials. The materials furnished shall be designed, constructed, and installed in accordance with the best practices and methods.

1.04 QUALIFICATIONS

B. Bidder must provide written evidence at time of bid of meeting qualifications herein pertaining to the directional drilling work they intend to self-perform. If Bidder intends to use a Subcontractor to perform any drilling activities, written evidence of the subcontractor’s ability to meet the qualifications herein pertaining to that activity must also be provided at time of bid. Include the names of the contracts, the contract award amounts, the length and time required for completion of each segment of directional drill (include setup, drilling and pullback), size of pipe, and the names, addresses and telephone numbers of the owners.

No award will be made to any Bidder and his selected agents that cannot meet all of the following requirements:

1. HDD Contractor shall have a minimum of five (5) years of experience in HDD pipeline applications.

2. CONTRACTOR shall have experience in at least three (3) similar projects in the past five (5) years where CONTRACTOR was responsible for installing pipelines by directional drill across water bodies or FDOT roadways. For each of these projects, the minimum pullback diameter shall be twelve (12) inches and the minimum boring distance shall be 500 feet.

3. The HDD CONTRACTOR shall provide written evidence of successful project experience, minimum one (1) directional drilling project, for each of the following conditions. Evidence can be in the form of a single project or separate projects as needed to meet the following:

a. Performed in close proximity to commercial businesses and facilities.

b. Effectively contained and immediately responded to inadvertent returns in accordance with the project’s frac-out contingency plan.

c. Performed in similar soils to those of this project

C. Horizontal directional drilling (“HDD”) Supervisor shall demonstrate recent (within the last 3 years) direct experience in successfully completing HDD projects of a similar pipe size, length, and complexity.

D. Operators of the drill rig shall demonstrate a minimum of 12 months experience in the operation of the proposed drill rig.

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1.05 JOB CONDITIONS

A. Owner shall obtain legal access to the project site as necessary for construction activities.

CONTRACTOR shall be responsible for construction relating to accessing the project site as directed by the Owner and Engineer.

B. CONTRACTOR shall comply with all special conditions as stated in the permits.

C. CONTRACTOR shall secure a site for disposal of drilling spoils. CONTRACTOR shall submit information regarding site for disposal including agreements for disposal and all necessary permits required for disposal.

PART 2 - PRODUCTS

2.01 EQUIPMENT

A. General: All equipment in the directional bore shall have the capacity, stability, and necessary safety features required to fully comply with the specifications and requirements of this section without showing evidence of undue stress or failure. It shall be the responsibility of the CONTRACTOR to assure that the equipment to be used in the directional bore is in sound operating condition. Backup equipment may be required in the event of an equipment breakdown and where the condition of the equipment to be used indicates that routine component replacement or repair will likely be necessary during the directional bore.

B. Directional Drilling System: The directional drilling equipment shall consist of truck-mounted field power unit and a trailer or dolly-mounted drill unit. A minimum crew of three people is required to operate the units. All tunneling system components shall be in sound operating condition with no broken welds, excessively worn parts, badly bent, or otherwise misaligned components. All ropes, cables, clamps, and other non-mechanical but essential items shall be in sound condition and replaced immediately when need is apparent.

1. Field Power Units: The field power unit shall be a self-contained system designed to provide a supply of high-pressure cutting fluid to the drill unit. It shall contain two fluid storage tanks and two complete mixing systems. The cutting fluid is to be mixed on site without the need for an external water supply. It shall permit changes to be made to the drilling fluid concentration during tunneling in response to changing soil conditions. The field power unit shall contain the power-taken off-driven high-pressure drilling fluid pumping system.

2. Directional Drill System: A dolly-mounted version of the drill system shall include a thrust frame. Both the trailer-mounted and dolly-mounted drill systems shall be designed to rotate and push 10-foot (3-meter) minimum hollow drill sections into the tunnel being created by the boring head. The drill sections may be made of high-strength steel, which permits them to bend to a 30-foot (9-meter) radius without yielding. Drill end fittings shall permit rapid make-up of the drill sections while meeting the torque, pressure and lineal load requirements of the system. The boring head itself shall be capable of housing a probe used by the guidance system to determine tool depth and location from surface and to orient the head for steering.

3. Restrictions: Other devices or utility placement systems for providing horizontal

41105-001: 02320-7 thrust, other than those previously defined in the preceding Sections, shall not be used unless approved by the ENGINEER prior to commencement of the work.

Consideration for approval will be made on an individual basis for each specified location. The proposed device or system will be evaluated prior to approval or rejection on its potential ability to complete the utility placement satisfactorily without undue stoppage and to maintain line and grade within the tolerances prescribed by the particular condition of the project. Water sluicing methods, jetting with compressed air, or boring or tunneling devices with vibrating type heads that do not provide positive control of the line and grade shall not be allowed.

C. Drilling Fluid (Mud) System & Spoils Equipment: A self-contained, closed, drilling fluid mixing system shall be of sufficient size to mix and deliver drilling fluid. Mixing system shall continually agitate the drilling fluid during operations. Connections between the pump and drill pipe shall be relatively leak free.

1. Used drilling fluid and drilling fluid spilled during drilling operations shall be contained and conveyed to the drilling fluid recycling system. Pumps and/or vacuum trucks of sufficient size shall be in place to convey excess drilling fluid from containment areas to storage and recycling facilities.

2. CONTRACTOR shall provide a mud cleaning system of sufficient capacity to handle expected slurry quantities for this project. The recycling system shall separate sand, dirt, and other solids from the drilling fluid to render the drilling fluid re-usable. Spoils separated from the drilling fluid will be stockpiled for later use or disposal.

3. CONTRACTOR shall provide a rigid tank of suitable material as a return tank for recovered slurry. Lined slurry pits will not be acceptable.

4. CONTRACTOR shall provide a rigid tank of suitable material as a temporary containment tank for clarified water from the slurry separation equipment. The containment tank shall hold clarified water until it can be pumped back into the outfall line for disposal. Lined pits will not be acceptable.

D. Guidance System: A Magnetic Guidance System (MGS) probe and tracker or Gyrsoscopic system shall be used to continuously monitor the location of the drill head during the drilling operation. The guidance shall be capable of tracking at all depths up to eighty feet and in any soil condition, including hard rock. It shall enable the driller to guide the drill head by providing immediate information on the tool face, azimuth (horizontal direction), and inclination (vertical direction). The guidance shall be accurate to +/-2% of the vertical depth of the borehole at sensing position at depths up to eighty feet and accurate to two (2) feet horizontally. The guidance system shall be of a proven type and shall be operated by personnel trained and experienced with the system. The operator shall be aware of magnetic anomalies on the surface of the drill path and shall consider such influences in the operation of the guidance system if using a magnetic system.

1. The MGS shall be a licensed and approved wire guidance system and shall be set up and operated by personnel experienced with this system. A “Walk-over” tracking system shall not be used. CONTRACTOR shall provide Engineer with current calibration certification of MGS in accordance with manufacturer’s specifications. The CONTRACTOR shall supply all components and materials to install, operate, and maintain the MGS. This shall include, but not be limited to the following:

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a. MGS Probe and Interface

b. Computer, Printer, and Software

c. DC Power Source, Current Control Box, and Coil/Tracking Wire.

2. The boring tool shall have steering capability and have an electronic tool detection system. The position of the tool during operation shall be capable of being determined accurately, horizontally within 1% of the horizontal distance of the borehole and vertically within 2% of the vertical depths of the borehole. The boring tool shall have a nominal steering radius of 30 feet.

3. Bore Tracking and Monitoring: At all times during the pilot bore the CONTRACTOR shall provide and maintain a bore tracking system that is capable of accurately locating the position of the drill head in the X, Y and Z axes. The CONTRACTOR shall record these data at least once per drill pipe length of every twenty (20) feet, whichever is most frequent, and the data logged shall be tied to the surface grid tracking system. If Owner and Engineer allow a “walk-over” system to be utilized, the CONTRACTOR shall mark or stake the horizontal location of the bore at the frequency noted above for field-survey of as-built location.

4. Downhole and Surface Grid Tracking System: CONTRACTOR shall monitor and record X, Y, and Z coordinates relative to an established surface survey benchmark and baseline stationing that is tied to existing, fixed and visible sight features. The survey baseline shall be referenced to the project’s specified horizontal and vertical datums. The data shall be continuously monitored and recorded at least once per drill pipe length or every twenty (20) feet, whichever is more frequent.

5. Deviations: All deviations between the recorded and design bore path shall be calculated and reported on the daily log. If the deviations exceed +/- 2% of the vertical depth of the borehole at sensing position and/or two (2) feet horizontally from the design path, such occurrences shall be immediately reported to the Owner/Engineer.

The CONTRACTOR shall undertake all necessary measures to correct deviations and return to design line and grade. Bore paths with regional high spots will be rejected.

E. Instrumentation:

1. Drilling Fluid: Provide and maintain instrumentation which will accurately locate the pilot hole and measure drilling fluid flow discharge rate and pressure. Fluid flow rates and pressures shall be monitored and recorded by the CONTRACTOR during pilot bore drilling, reaming and pullback operations. Allow Owner access to these instruments and their readings at all times. Plot the horizontal and vertical location of the pilot bore at intervals not to exceed 10 feet.

2. Pullback Force: If equipment proposed is rated for a maximum thrust greater than 85% of the published safe pull load (at 12 hours) for the product pipe, CONTRACTOR shall provide an in-line pull force monitoring device (i.e. strain gauge) to monitor pullback force during pullback. Alternatively, a breakaway coupling may be utilized.

2.02 HDPE PIPE AND ACCESSORIES

A. High density polyethylene (HDPE) pipe shall conform to the contract documents.

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B. Pipe pulling bell assemblies shall be designed and furnished by pipe manufacturer. The pulling bell assemble shall have the same performance characteristics as the pipe to which it is connecting. They shall also be fabricated with filling/testing ports, of appropriate size, for testing of the pipe after it is pulled through the bore path. For pipe that is installed using the Assembled Line method, described as follows, the pulling bell may also be used to test the pipe prior to pull back.

C. The manufacturer shall have representative proof-of-design tests of flexible restrained pipe joints as well as of the pipe pulling bell assemblies that establish the basis for the maximum allowable pulling loads indicated herein.

D. Two #6 AWG stranded copper wires with blue insulation (for water) shall be installed with the pipeline for pipeline locating purposes. The wire shall be terminated in a wire access box with ground rods as required at both ends. If bored, the CONTRACTOR shall attach the wire to the HDPE pipe in such a way as to not break the wire during the pullback of the pipe.

2.03 DRILLING FLUIDS

A. CONTRACTOR shall select drilling fluids appropriate for this application and submit detailed technical information and specification on selected drilling fluids for approval by the Engineer prior to use. CONTRACTOR shall select drilling fluids suitable for soil conditions at the site. All drilling fluids shall be easily flushed from the pipe and screen after installation to ensure proper screen development and to prevent clogging of screen.

B. All drilling fluids shall be environmentally safe, non-corrosive, and not harmful to installed components.

C. Disposal of fluids is the responsibility of the CONTRACTOR. Dispose of fluids in a manner that is in compliance with all permits and applicable federal, state and local regulations.

PART 3 - EXECUTION

3.01 GENERAL

A. Install HDPE pipe by directionally controlled horizontal drilling. This process includes drilling a small diameter pilot hole in a vertical arc from the rig side to the pipe side, and then reaming out the hole until the water main can be pulled through for a complete installation.

B. The CONTRACTOR shall be responsible for the design, adequacy and methodology of the bored pipe installation.

C. A competent and experienced supervisor for the HDD CONTRACTOR must be present at all times during drilling operations.

D. All excavations and pits shall be well sheeted and braced as necessary for safe and adequate access for workmen, inspections, and materials and shall be of a size suitable to equipment and material handling requirements.

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E. The CONTRACTOR may, at their option, use a starter casing at the entry and exit point of the HDD. The dimensions of the starter casing shall be as needed to adequately protect existing utilities and infrastructure.

F. The following is a sequence of steps must be adhered to for the directional bore operation:

1. Track out the boring path (enter, push through, and exit the ground). Great care must be taken to cease pumping of drilling fluid as soon as the drill head exits the ground to minimize spilling of drilling fluids.

2. Pull back the utility pipe through the boring path with a back reamer leading the pipe.

3. Flush out pipeline until bentonite slurry, other drilling fluids, and fines have been removed from around the pipeline.

G. If equipment breakdown or other unforeseen stoppages occur and forward motion of the directional cutting head is halted at any time other than for reasons planned in advance (addition of drill stems, etc.), the boring path shall be filled with a proper bentonite solution immediately, or as directed by the Engineer.

3.02 HDPE PIPE

A. High density polyethylene (HDPE) pipe shall be installed to the requirements of the contract documents.

B. After the directionally drilled pipe has been successfully installed, allow the pipe to recover for 24 hours prior to making further connection to new or existing systems. The CONTRACTOR is responsible for ensuring that a sufficient length of the pipe has been pulled through the hole so that the pull-nose is not pulled back into the bore hole due to stretch recovery of the pipe.

C. Completed installation shall be subject to hydrostatic test as required herein.

3.03 PILOT HOLE

A. The pilot hole shall be drilled along the path shown on the construction Plans to the following tolerances:

1. Elevation: Plus zero (0) feet, minus five (5) feet. Provide minimum cover below roads, and channel bottom as specified on the plans.

2. Separation from Utilities: 24” minimum, outside of existing pipe to outside of final borehole.

3. Alignment: Plus or minus three (3) feet, or where more stringent as specifically indicated on the Plans.

4. Radius: the minimum allowable radius is 30 feet times the pipe outside diameter in inches, or where more stringent as specifically indicated on the Plans.

5. Entry Point Location: The pilot hole shall initially penetrate the ground surface at the exact location intended.

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6. Exit Point Location: The pilot hole shall finally penetrate the ground surface within plus or minus three (3) feet of the alignment shown in the construction drawings and within plus or minus five (5) feet of the length shown on the Plans.

B. Prior to drilling confirm all utility locations and elevations for utilities crossed by directional drill. If utility cannot be exposed due to depth, contact utility owner to verify depth. If drilling within 3 feet of an existing parallel utility, the utility must be physically exposed at least every 25 feet.

C. At the completion of pilot hole drilling, CONTRACTOR shall provide a tabulation of coordinate references to the drilled entry point which accurately describe the alignment and grade of the pilot hole. Submit a layout at a scale of 1 in. = 20 ft. horizontal and vertical or the actual installed location of the pipeline.

D. In the event that pilot does deviate from the bore path more than allowable tolerances, CONTRACTOR will notify the ENGINEER who may require the CONTRACTOR to pull-back and re-drill from the location along bore path before the deviation.

E. Upon completion of pilot hole phase of the operation, a complete set of “as-built” records shall be submitted in duplicate to the ENGINEER. Pilot bore path record drawings will be reviewed within 24 hours of submittal. These records shall include copies of the pilot bore path plan and profile record drawing, as well as directional survey reports as recorded during the drilling operation. Upon approval of the pilot hole location by the ENGINEER and OWNER the hole opening or enlarging phase of the installation shall begin. Reaming of the pilot hole will not proceed until approval from the

ENGINEER/OWNER.

3.04 HDD INSTALLATION

A. Pre-reaming operations shall be conducted at the discretion of the horizontal drilling CONTRACTOR. All provisions of this specification relating to simultaneous reaming and pulling back operations shall also pertain to pre-reaming operations.

B. All back reaming must utilize trailing rods.

C. A swivel shall be used to connect the pipeline pull section to the reaming assembly to minimize torsional stress imposed on the section.

D. The pull section shall be supported as it proceeds during pull back so that it moves freely and the HDPE pipe is not damaged or overstressed.

E. Disposal of drilling fluids, at approved off-site locations, shall be the responsibility of the

CONTRACTOR and shall be conducted in compliance with all pertinent environmental regulations, right-of-way and workspace agreements and permit requirements. Disposal of drilling fluids into drainage courses shall not be allowed.

F. Drilling fluid returns at locations other than the entry and exit points shall be minimized.

CONTRACTOR shall immediately clean-up inadvertent returns. Do not allow drilling mud to flow freely on the site or around the entrance or exit pits. Remove spilled mud and restore ground to original condition.

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G. Assembly pit shall be constructed in accordance with other applicable Sections of the Contract. Construction to take care to not excavate pit larger than required for HDD HDPE installation. All soil erosion measures must be in place prior to excavating pit.

H. Pipe rollers shall be of sufficient size to fully support the weight of the pipe while being hydro-tested and during pull-back operations. Sufficient number of rollers shall be used to prevent excess sagging of pipe.

I. If any driveways or access roads are to be blocked by the pipe, the CONTRACTOR shall provide overhead roll-type pipe stands to elevate the pipe to such a height as to allow access into the driveways and/or access roads. CONTRACTOR shall submit the proposed layout location for approval.

J. The handling of the assembled pipeline shall be in such a manner that the pipe is not damaged by dragging it over sharp or cutting objects. Slings for handling the pipeline shall not be positioned at pipe joints. Sections of the pipes with cuts and gouges or excessive deformations shall be removed and replaced.

3.05 QUALITY CONTROL

A. CONTRACTOR shall take care not to damage any materials during HDD operations. All pipes shall be visually inspected for gouges. Gouges in excess of 10 percent of the pipe wall thickness are not acceptable. In areas where excessive gouges are present, the affected pipe section shall be cut out and the remaining pipe butt fused to make a continuous section.

B. The angle of ramp approaches shall be carefully considered/controlled to keep joint articulation to within allowable deflection limits of the pipe joints.

C. After installation of the pipeline, conduct an internal inspection of the pipeline, in the presence of the Engineer, using a mandrel or pipeline pig designed for that purpose to demonstrate that the pipe has not collapsed or deflected excessively. The outside diameter of the mandrel or pig shall be minimum 90 percent of the pipeline internal diameter.

Devices pulled through the water main shall be designed to prevent damage to the HDPE pipe.

D. The MGS as-built data shall be recorded at the intervals stated herein during the actual crossing operation. The CONTRACTOR shall furnish “As-Built” plan and profile drawings based on these recordings showing the actual location horizontally and vertically of the installation and all utility facilities found during the installation.

E. The CONTRACTOR shall hydrostatically test the pipeline(s) in accordance with contract documents.

F. In the event of failure to install the directionally drilled pipelines, the CONTRACTOR shall retain possession of any CONTRACTOR-supplied HDPE pipe and remove it from the site.

The bore holes shall be completely filled with grout. If the pipe cannot be removed from the bore hole, it shall be cut off 5 feet below ground, and the pipe and annular space shall be grouted.

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