REHABILITATION OF SEWER BY PIPE BURSTING/REPLACEMENT PROCESS

     PART 1      GENERAL

 1.01      DESCRIPTION

 A.  This clause includes requirements to rehabilitate existing sanitary sewers by the approved pipe bursting method and immediately installing a new polyethylene pipe, reconnect existing sewer house connections, television inspection of the polyethylene pipe and complete installation in accordance with the Contract documents. Only static pull pipe bursting equipment manufactured by Innovative Trenchless Systems Inc. (ITS) (318.396.6160) or approved equal is accepted for this project.

 B.  Sound emissions from the pipe bursting/replacement process shall be limited to 68 decibels (dB) during the installation process.  The Contractor shall provide silencers or other devices to reduce machine noise to meet these requirements.

 C.  No Pipe Bursting restoration will be accepted that has created a sag in the restored line (not previously inherent to the existing line). The Contractor shall be responsible for correcting any sags in the line he creates. 

             D.          Contractor shall take all safety measures necessary to protect the public from open excavations.

 1.02      QUALITY ASSURANCE 

A.          The Contractor shall be certified by the particular Pipe Bursting System Manufacturer that such firm is licensed installer of their system. 

B.          Polyethylene pipe jointing shall be performed by personnel trained in the use of thermal butt-fusion equipment and recommended methods for new pipe connections. Personnel directly involved with installing the new pipe shall receive training in the proper methods for handling and installing the polyethylene pipe. Training shall be performed by qualified representative. 

C.          The Contractor shall hold the Owner and Engineer harmless in any legal action resulting from patent infringements. 

D.                 The Contractor must have successfully completed at least one (1) job, similar in scope, to the requirements of pipe-bursting set forth in these bid documents. 

E.                  The pipe bursting system manufacturer and/or the certified licensed Contractor must have a minimum of 4 years experience using the subject static pull pipe bursting system and no less than 100,000 L.F. of Certified successful installations. 

1.03      SUBMITTALS 

A.          Contractor’s submittals shall include the following:

 1.      Shop drawings, catalog data, and manufacturer’s technical data showing complete information on material composition, physical properties, and dimensions of new pipe and fittings. Include manufacturer’s recommendation for handling, storage, and repair of pipe and fittings damaged.

2.      Method of construction and restoration of existing sewer service connections. This shall include:

      Detail drawings and written description of the entire construction procedure to install pipe, bypass sewage flow and reconnection of sewer service connections.

3.      Certification of workmen training for installing pipe. 

4.      Television inspection reports and video tapes made before and after new pipe installation.

 1.04      DELIVERY, STORAGE, AND HANDLING 

A.          Transport, handle, and store pipe and fittings as recommended by manufacturer. 

B.          If new pipe and fittings become damaged before or during installation, it shall be repaired as recommended by the manufacturer or replaced as required by the Engineer at the Contractor’s expense, before proceeding further. 

C.          Deliver, store and handle other materials as required to prevent damage.

 1.05      APPROVED PIPE BURSTING SYSTEMS

 A.                 The system approved for rehabilitating existing pipe systems by means of pipe bursting and the installation of HDPE pipe is Innovative Trenchless Systems, Inc.  (ITS) or approved equal. 

PART 2 - PRODUCTS

 2.01      MATERIALS 

A.             Polyethylene Plastic Pipe shall be high density polyethylene pipe and meet the applicable requirements of ASTM F714 Polyethylene (PE) Plastic Pipe (SDR-PR) based on outside diameter, ASTM D1248, ASTM D3550.

 1.      Sizes of the insertions to be used shall be such to renew the sewer to its original or greater than flow capacity. 

2.      All pipe shall be made of virgin material. No rework except that obtained from the manufacturer’s own production of the same formulation shall be used. 

3.      The liner material shall be manufacture from a High Density High Molecular weight polyethylene compound which conforms to ASTM D- 1248 and meets the requirements for Type III, Class C, Grade P-34, Category 5, and has a PPI rating of PE 3408. 

4.      The body of the pipe produced from this resin have a minimum cell classification of 345444C under ASTM D-3350 and the inner wall shall be light in color and have a minimum cell classification of 345444E under ASTM D-3350.  A higher cell classification limit which gives a desirable higher primary property, per ASTM D-3350 may also be accepted by the Engineer at no extra cost to the owner.  The value for the Hydrostatic Design basis shall not be less than 1600 PSI (11.03 MPA) per ASTM D-2837. 

5.      The pipe shall be homogenous throughout and shall be free of visible cracks, holes, foreign material, blisters, or other deleterious faults.

6.      Dimension Ratios:  Using the static pull pipe bursting system; the minimum wall thickness of polyethylene pipe shall be SDR 17 (IPS). 

7.      Material color shall be preferably gray on the exterior and interior.  Light interior color is better suited for CCTV Inspection.

 2.02      MANUFACTURER TESTING

 A.     Tests for compliance with this specification shall be made as specific herein and in accordance with the applicable ASTM Specification. A certificate with this specification shall be furnished, upon request, by the manufacturer for all material furnished under this specification. Polyethylene plastic pipe and fittings may be rejected if they fail to meet any requirements of this specification. 

2.03          USE OF CLAMP AND ENCASEMENT

 A.  Where excavations for the insertion of the replacement pipe are made between two manholes, the ends of the HDPE will be cut smooth and square to the axis, so that it can be joined in a workman like manner such that both ends meet the touch uniformly and continuously. An all stainless steel (including bolts and Iugs) full circle universal clamp coupling with a ¼” inch minimum thickness grid type gasket shall be used, JCM Industries Type 108 or equal. Clamps shall be selected to fit the outside diameter of the replacement pipe. Minimum clamp widths shall be provided in accordance with the following Table: 

                       MINIMUM CLAMP WIDTHS

 OUTSIDE DIAMETER OF LINER PIPE                             MINIMUM WIDTH OF CLAMP

           (Inches)                                                                      (Inches)

                                     7.125                                                                             15

                                     8.625                                                                             18

                                   10.750 or Greater                                                         30

2.04      BEDDING

.            In all excavations where the replacement pipe is uncovered (i.e. insertion pits, sag elimination pits), bedding as shown on the drawings shall be installed. Visual inspection is required for approval of bedding before backfill is completed.

PART 3 - EXECUTION

3.01     PREPARATIONS

 The Contractor shall submit a work plan to the Engineer for review and acceptance. The work plan shall address the following minimum preparation/steps, unless approved otherwise by the Engineer.

 A.          SAFETY

             The contractor shall carry out operations under this section in strict accordance with all applicable OSHA Standards. Particular attention is drawn to those safety requirements involving work on an elevated platform and entry into a confined space. It shall be the Contractor’s responsibility to comply with OSHA Standards and Regulations pertaining to all aspects of the work. 

B.          PRE-INSTALLATION TELEVISION INSPECTION 

             It shall be the responsibility of the Contractor to video (TV) inspect the sewer pipe immediately before the pipe bursting to assure that the existing pipe conditions are acceptable for pipe bursting. This inspection as well as the video (TV) inspection after the installation, shall be incidental to the installation of the replacement pipe. 

C.          BY PASSING SEWAGE 

             The Contractor shall provide for continuous sewage flow around the section(s) of pipe designated for the installation of replacement pipe. The pump bypass lines shall be of adequate capacity and size to handle the flow. Bypass pumping shall be considered incidental to the installation of the liner. 

D.          LINE OBSTRUCTIONS

             If Pre-lnstallation video (TV) inspection reveals and obstruction in the existing sewer (heavy solids, dropped joints, protruding service taps or collapsed pipe) which will prevent completion of the pipe bursting/crushing process, and that cannot be removed by conventional sewer cleaning equipment, then an Obstruction Removal shall be made by the Contractor, with the approval of the Engineer. Obstruction removal shall be done by the method of:  pipe replacement, digging an obstruction elimination pit and bringing the bottom of the pipe trench to a uniform grade in line with the existing pipe invert or by other measures AS APPROVED BY THE ENGINEER. 

E.          SAGS IN LINE

             If Pre-Installation video (TV) inspection reveals a sag in the existing sewer that is greater than one-half the diameter of the existing pipe, it shall be the Contractor’s responsibility to install the replacement pipe to result in an acceptable grade without the sag. The Contractor shall take the necessary measures to eliminate these sags by the method of: pipe replacement, digging a sag elimination pit and bringing the bottom of the pipe trench to a uniform grade in line with the existing pipe invert or by other measures. 

F.           SERVICE RECONNECTIONS

             The Contractor shall be responsible for continuity of sanitary sewer service to each customer connected to the section of sewer during the execution of the work.  If sewage backup occurs and enters buildings, the Contractor shall be responsible for clean-up, repair, property damage cost and claims.

             The contractor shall present a plan for disconnection and reconnection of the service lines.  Contractor shall use any means necessary to ensure that service lines are reconnected in an expedient manner and that very minimal interruption of services occurs.  It shall be the Contractor’s responsibility to notify affected customers of such interruptions with at least a 48-hour notice.

3.02     INSTALLATION PROCESS 

The Contractor shall submit information, in detail, of the procedure and the steps to be followed for the installation of the pipe bursting/crushing method selected, even if the process is named in the specification. All such instructions and procedures submitted shall be carefully followed during installation. Any proposed submitted shall be carefully followed during installation. Any proposed changes in installation procedures shall require submittal of revised procedures and acceptance by the Engineer.

A.         FINISHED PIPE

The installed replacement pipe shall be continuous over the entire length of each pipe segment from manhole to manhole and shall be free from visual defects such as foreign inclusions, concentrated ridges, discoloration, pitting, varying wall thickness and other deformities. Replacement pipe with gashes, nicks, abrasions, or any such physical damage which may have occurred during storage and/or handling, which are larger/deeper than 10% of the wall thickness shall not be used and shall be removed from the construction site. The replacement pipe passing through or terminating in a manhole shall be carefully cut out in a shape and manner approved by the Engineer. The invert and benches shall be streamlined and improved for smooth flow. The installed pipe shall meet the leakage requirements of the pressure test specified herein.

B.         PIPE JOINTING

.         The polyethylene pipe shall be assembled and joined at the site using the thermal butt-fusion method to provide a leak proof joint.  Threaded or solvent-cement joints and connections are not permitted.  All equipment and procedures used shall be used in strict compliance with the manufacturer=s recommendations.  Fusing shall be accomplished by personnel certified as fusion technicians by a manufacturer of polyethylene pipe and/or fusing equipment.

2.         The butt-fused joint shall be true alignment and shall have uniform double roll-back beads resulting from the use of proper temperature and pressure. The joint surfaces shall be smooth. The fused joint shall be watertight and shall have tensile strength equal to that of the pipe. All joints shall be subject to acceptance by the Engineer and/or his representative prior to insertion.  It shall be the sole responsibility of the Contractor to provide an acceptable butt-fusion joint.  All defective joints shall be cut out and replaced at no cost to the City. Any section of the pipe with a gash, blister, abrasion, nick, scar, or other deleterious fault greater in depth than ten percent (10%) of the wall thickness, shall not be used and must be removed from the site.  However, a defective area of the pipe may be cut out and the joint fused in accordance with the procedures stated above.  In addition, any section of pipe having other defects such as concentrated ridges, discoloration, excessive spot roughness, pitting, variable wall thickness or any other defect of manufacturing or handling as determined by the Engineer and/or his representative shall be discarded and not used.

3.         Terminal sections of pipe that are joined within the insertion pit shall be connected with a full circle pipe repair clamp. The butt gap between pipe ends shall not exceed one-half (1/2) inch.  The maximum length of continuous replacement pipe which shall be assembled above ground and pulled on the job site at any one time shall be 600 linear feet. 

C.         INSERTION OR ACCESS PITS

 1.         The location and number of insertion pits shall be planned by the Contractor and submitted in writing for approval by the Engineer prior to excavation. The pits shall be located such that their total number shall be minimized and the length of replacement pipe installed in a single pull shall be maximized. Locations of damaged pipe shall be used for insertion pits if directed by the Engineer.

2          The cost of diversion pumping required around and insertion pit, from a manhole upstream to a manhole downstream, shall be per applicable item of these specifications.

3.         Excavation for insertion pits shall not be paid for separately but shall be included in the unit price bid for bursting, including any costs for street removal and repair unless otherwise noted on the plans (saw cutting when no joints are available shall be required at no additional cost).

 D.        PROCESS LIMITATIONS

1.         Though the installation process may be licensed or proprietary in nature, the Contractor SHALL NOT change any material, thickness, design values or procedures matters stated or approved in the submittals, without the Engineer’s prior knowledge and pre-approval. The Contractor shall submit, in writing, full details about component materials, their properties and installation procedures and abide by them fully during the entire course of the project.

2.        It is the Contractor’s responsibility to examine the proposed line segment and notify the Engineer if conditions exist that could cause problems with the pipe bursting/crushing method. These could include but not be limited to nearby services that could be damaged by the operations, existing slabs that could be damaged, or less than acceptable depth of cover. The intent of the project is to fully rehabilitate the pipe segment shown on the plans.  Partial installations shall not be accepted. 

3.03     SEALING AND BENCHES IN THE MANHOLE

A.         The replacement pipe shall be installed with a tight fitting seal with the existing or new manhole. The Contractor shall use methods such as (but not limited to) a relaxation period to ensure that connections of the new lines to the manholes will not pull apart. Half-inch diameter activated oakum band soaked in Scotch seal 5600 or equal shall be applied circumferentially on the replacement pipe and encased with a cemetitious mortar to prevent inflow at the manhole. The top half of the pipe within the manhole shall be neatly cut off and not broken or sheared off, at least four inches away from the manhole walls. The channel in the manhole shall be a smooth continuation of the pipe(s) and shall be merged with other lines or channels, if any. Channel cross-section shall be U-shaped with a minimum height of half pipe diameter to three-fourths of the pipe diameter for fifteen inches and larger. The side of the channels shall be built up with mortar/concrete, as specified, to provide benches at a maximum of 1 in 12 pitch towards the channel.

B.               The replacement pipe in the manhole shall be locked down and sealed as specified above before proceeding on to the next manhole section and all manholes shall be individually inspected for replacement pipe cut-offs, benches and sealing works.

C.       The Contractor shall install all pulleys, rollers, bumpers, alignment control devices and other equipment required to protect existing manholes, and to protect the pipe from damage during installation. Lubrication may be used as recommended by the manufacturer. Under no circumstances will the pipe be stressed beyond its elastic limit.

3.04     SERVICE LINE CONNECTION RESTORATION

A.         All sewer service connections shall be identified, located, excavated and disconnected prior to the pipe insertion to expedite reconnection. Upon commencement, pipe insertion shall be continuous and without interruption from one manhole to another, except as approved by the engineer and/or his representative. Upon completion of insertion of the new pipe, the contractor shall expedite the reconnection of services so as to minimize any inconvenience to the customers.  The following are acceptable service line reconnection methods.  Contractor shall submit selected method for approval.  When saddles are used, they shall have enough surface area around the pipe to withstand downward loads.

i.              Sewer service connections shall be connected to the new pipe by PVC Saddle Wyes, including all equipment, labor, materials and procedures; and all else incidental thereto required to install PVC saddle wyes.

ii.              Mechanical saddles shall be made of polyethylene pipe compound that meets the requirements of ASTM D1248, Class C, have stainless steel straps and fasteners, neoprene gasket and backup plate. Mechanical saddles shall be Strap-On-Saddle Type as manufactured by Driscopipe or Tapping Saddle manufactured by Fernco Joint Sealer Co., DFW Plastics, Inc. or approved equal.

iii.               An HDPE branch saddle may be sidewall fused onto the O.D. of the installed HDPE pipe.  This may be done with commercially available sidewall Fusion machine or installed with “Unicore” HDPE splice under the base of saddle and heated to pipe O.D.

B.                  PE to PVC transition fittings shall be used as required to tie service connection to customer’s line.

C.           Sewer service connections shall be connected to the new pipe by mechanical methods. Once the saddle is secured in place, drill hole full inside diameter of saddle outlet in pipe liner.

3.05     TESTING OF THE REPLACEMENT PIPE

A.         All costs of testing the replacement pipe by a pressure method will be incidental to the installation. Two types of testing shall be required after the replacement pipe has been installed in the existing sewer main. The first is a low-pressure air test of the replacement pipe before it has been sealed in place at the manholes, and before any service reconnections have been made. The purpose of this test is to check the integrity of the joints that have been made and to verify that the replacement pipe has not been damaged by inserting it into the sanitary sewer.

B.         Low Pressure Air Test Procedure: After a manhole-to-manhole section of sanitary sewer main has been pipe bursted/crushed and prior to any service lines being connected to the replacement pipe, the pipe shall be plugged at each manhole with pneumatic plugs. The design of the plugs shall be such that they will hold against the test pressure without requiring external blocking or bracing. One of the plugs shall have three air hose connections: one of the inflation of the plug, one for reading the air pressure in the sealed line, and one for introducing air into the sealed line

C.         Low pressure air shall then be introduced into the sealed line until the internal air pressure reaches 4.0 psig greater than the average back pressure resulting from any groundwater that may be over the pipe. At least two minutes shall elapse to allow the pressure to stabilize.

D.         The time required for the internal pressure to decrease from 3.5 to 2.5 psig greater that the average back pressure resulting from any groundwater that may be over the pipe, shall not be less than the time shown for a given pipe diameter in the following table.

Carrier Pipe Diameter (Inches)                                        Minimum Elapsed Time (Minutes)

                           8                                                                                  4

                         10                                                                                  5

                         12                                                                                  6

                         15                                                                                  7

                         18                                                                                  8

3.06     POST TELEVISING OF COMPLETED SECTIONS

A.         The Contractor shall provide the Owner a color video tape taken by a 360 degree radial view camera for close up view showing the completed work, including the condition of the restored taps. Post Televising is incidental to the cost of the replacement pipe.

B.         Television inspections, tapes and reports, etc., shall be in accordance with applicable sections of the specifications. Upon completion of the installation work and testing, the Contractor shall restore/clear the project area affected by his operations. No trash, rubbish, etc. shall be stored at any site, whether the work is in progress or not.

C.         Defects which may affect the integrity or strength of the pipe in the opinion of the Engineer shall be repaired or the pipe replaced at the Contractor’s expense.

3.07     TESTING OF SERVICE LINES

                        A.         A smoke test shall be performed in each rehabilitated sanitary sewer manhole section to determine if all existing service connections have been reconnected to the rehabilitated sewer and to check the integrity of the connection of the newly replaced service tap, both to the liner and to the existing private service connection.  No taps shall be backfilled until completion of this test.  Only those taps in one manhole section shall be tested at any one time thus preventing a large number of open excavations which could be a hazard to the public.  Smoke testing shall be performed in accordance with the appropriate section of these specifications.

                        B.         All taps/connections noted as leaking shall be repaired or replaced and then retested.  The Contractor will be allowed to leave the tap/connection exposed in only one manhole section at a time to minimize inconvenience and hazard to the residents.  If tap/connection repair or replacement, testing or retesting, and backfilling of the excavation is not completed within the work day, the Contractor shall properly barricade and cover each excavation with plywood, steel plates, or some other approved material, to the satisfaction of the Engineer.
                        C.         On houses where smoke does not issue from the plumbing vent stacks to confirm the reconnection of the sewer service to the newly installed liner pipe, a dye test will be required to confirm the reconnection.  Dye shall be introduced into the service line through a plumbing fixture and flushed with water.  The Contractor will observe the flow at the service reconnection, or downstream manhole.  Detection of the dye shall confirm a reconnection.

3.08         WARRANTY

A.        All work performed under this Contract shall be warranted to be free from defects in material and workmanship for a period of one year from the date of final acceptance by the Owner.  If the engineer determines that the process has failed (including but not limited to the service connections), the Contractor shall perform any and all repairs at no additional cost to the Owner. 

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