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    SECTION 02766

    RELINING SANITARY SEWERS

   Note to specifier - Delete non applicable sections such as 2.02, 2.05, 2.06, etc.

   PART 1 - GENERAL

   1.01 SECTION INCLUDES

   A. Restoration of existing sanitary sewers by installation of a resin impregnated flexible felt tube into the existing sewer line utilizing a vertical inversion standpipe and hydrostatic head and curing by circulating hot water or other approved means to produce a hard, impermeable pipe.

   B. Restoration of existing sanitary sewers by installation of a folded and formed polyethylene or polyvinyl chloride liner pipe into the existing sewer line followed by inflation to its original configuration by circulating hot water or other approved method.

   C. Restoration of existing sanitary sewer by installation of a polyethylene or PVC pipe into the existing sewer line pipe by sliplining to produce a continuous, watertight length between adjacent manholes. The replacement pipe is either pulled or pushed into the bore and grouted in place.

   D. Restoration of existing sanitary sewer by installation of a polyethylene pipe into the existing sewer line pipe bursting/crushing in place to produce a continuous, watertight length between adjacent manholes. The process involves the use of a static, hydraulic, or pneumatic hammer “moling” device, suitably sized to break out the old pipe or using a modified boring “knife” with a flared plug that crushes the existing sewer pipe. Forward progress of the “mole” or the “knife” may be aided by the use of hydraulic equipment or other apparatus, as specified in the approved methods. The replacement pipe is either pulled or pushed into the bore.

   1.02 REFERENCES

   A. Codes, Specifications, and Standards:

   1. Codes, specifications, and standards referred to by number or title shall form a part of this specification to the extent required by the references thereto. Latest revisions shall apply, unless otherwise shown or specified.

   2. All pipe materials incorporated in the project shall be approved by the Tennessee Department of Environmental and Conservation for the application used prior to receipt of bids.

   B. American Society for Testing and Materials (ASTM) Standards:

   D638 Test Method for Tensile Properties of Plastics.

   D790 Test Methods for Flexural Properties of Un-reinforced and Reinforced Plastics and Electrical Insulating Materials.

   D-1248 Specification of Polyethylene Plastics Molding and Extrusion Materials.

   D-1693 Test Environmental Stress-Cracking of Ethylene Plastics.

   D-2122 Determining Dimensions of Thermoplastic Pipe and Fittings.

   D-2657 Practice for Heat-Joining Polyolefin Pipe and Fittings.

   D-2837 Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials.

   D-3035 Specification for Polyethylene (PE) Plastic Pipe (SDR-PR) Based of Controlled Outside Diameter (up to 6” IPS).

   D-3350 Specification for Polyethylene Plastics Pipe and Fittings Materials.

   F-585 Practice for Insertion of Flexible Polyethylene Plastics Pipe and Fittings Materials.

   F-714 Specification for Polyethylene (PE) Plastic Pipe (SDR-PR) Based on Outside Diameter (3” IPS and larger).

   F-1216 Rehabilitation of Existing Pipelines and Conduits by Inversion and Curing of a Resin-impregnated Tube.

   F-1504 Standard Specification for Folded Poly (Vinyl Chloride) (PVC) Pipe for Existing Sewer and Conduit Rehabilitation.

   F-1533 Standard Specification for Deformed Polyethylene (PE) Liner.

   C. National Association of Sewer Service Companies (NASSCO) Standards:

   NASSCO Specification - Recommended Specifications for Sewer Collection System Rehabilitation, July 1992.

   D. Related Sections

   1. Section 01025 - Measurement and Payment

   2. Section 01090 - Reference Standards

   3. Section 01340 - Shop Drawings, Product Data and Samples

   4. Section 01410 - Testing Laboratory Services

   5. Section 01560 - Temporary Controls

   6. Section 01710 - Cleanup and Restoration

   7. Section 02220 - Excavation, Backfilling, Compaction

   8. Section 02730 - Sanitary Sewage Systems

   9. Section 02762 - Sanitary Sewer Cleaning and Inspection

   10. Section 02763 - Gravity Sewer Rehabilitation

   11. Section 02764 - Internal Point Repairs

   12. Section 02765 - Sanitary Sewer Manhole Rehabilitation

   13. Section 02767 - Sewer Flow Control

   1.03 SUBMITTALS

   A. Submit the following:

   1. Manufacturer's Certificate of Compliance certifying compliance with the applicable specifications and standards.

   2. Certified copies of test reports of factory tests required by the applicable standards and this Section.

   3. Manufacturer's installation instructions and procedures.

   4. Contractor's procedures and materials for service renewal including time and duration of water and sewer service unavailability.

   5. Liner pipe sizing and wall thickness calculation data.

   6. For pipe bursting/crushing - system employed details/data.

   1.04 DELIVERY, STORAGE, AND HANDLING

   A. The Contractor shall be responsible for the delivery, storage, and handling of products. No products shall be shipped to the job site without the approval of the Owner's Representative.

   B. Keep products safe from damage. Promptly remove damaged products from the job site. Replace damaged products with undamaged products.

   PART 2 - PRODUCTS

   2.01 GENERAL

   A. Except as specifically stated otherwise in this Section, all products shall conform to the applicable requirements of the NASSCO Specification.

   B. The finished pipe liner in place shall be fabricated from materials which when complete is chemically resistant to and will withstand internal exposure to domestic sewage having a pH range of 5 to 11 and temperature of 150ºF.

   C. Field measurements of the existing pipe diameters, ovality and length shall be taken.

   D. The liner thickness shall be sized for a minimum hydrostatic load of 8.0 feet and maximum depth of earth cover as shown on the plans. The hydrostatic load shall be increased to the manhole depth plus 1.0 foot for bury depths in excess of 8.0 feet.

   2.02 POLYETHYLENE LINER PIPE FOR PIPE BURSTING/CRUSHING

   A. The sewer liner pipe and fittings shall be manufactured from high density polyethylene pipe compound which conforms to ASTM D1248 and meets the requirements for Type III, Class B, Category 5, grade P34 and has a PPI rating of PE3408. The pipe produced from this resin shall have a minimum cell classification of 345434D or E (inner wall shall be light in color to produce good quality VHS tapes from TV inspection) under ASTM D3350.

   B. Pipe made from this compound must have a long-term hydrostatic strength rating of 1600 psi or more, in accordance with ASTM D2837.

   C. When the environmental stress crack resistance (ESCR) of the compound is measured in accordance with ASTM D1693, Condition C, the compound shall withstand not less than 192 hours in 100% solution Igepal CO-630 at 100 degrees F before reaching a 20% failure point (F20).

   D. Tests for compliance shall be made according to the applicable ASTM specification. A certificate with this specification shall be provided by the manufacturer for all material furnished. The Owner reserves the right to witness inspection and test of the materials.

   E. The outside diameter of the liner shall be 8.625 inches with a standard dimension ratio (SDR) of 19 for insertion into a nominal 8 inch internal diameter existing sewer pipe.

   F. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet to the outlet of the respective manholes unless otherwise specified. The Contractor shall verify the lengths in the field before manufacturing.

   G. The liner pipe shall conform to the minimum structural standards for HDPE (Type III Resins) meeting ASTM D-3350-84, as listed below.

   U.S. Standard Results

   Flexural Stress (Yield) ASTM D-638 3,300 psi

   Flexural Stress (Break) ASTM D-638 4,500 psi

   Flexural Modulus of

   Elasticity ASTM D-790 145,000 psi

   2.03 CURED-IN-PLACE LINER

   A. All cured-in-place lining products shall comply with ASTM F-1216-91 or intent thereof as determined by the Engineer.

   B. The flexible tube shall be fabricated to a size that when installed will neatly fit (minimum 99.75%) the internal circumference of the existing sanitary sewer lines (including services). Allowance shall be made for circumferential stretching during insertion so that the final cured product is snug against the wall of the host pipe.

   C. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet to the outlet of the respective manholes unless otherwise shown or specified. The Contractor shall verify the lengths in the field before impregnation.

   D. Unless otherwise specified, the Contractor shall furnish a general purpose, unsaturated, polyester or thermosetting vinyl esther resin and catalyst system compatible with the reconstruction inversion process that provides cured physical strengths specified herein.

   E. Physical Strength:

   1. The cured pipe shall conform to the following minimum structural standards:

   Test Method Results

   Flexural Stress ASTM D790 4,500 psi

   Flexural Modulus of

    Elasticity ASTM D790 250,000 psi

   Tensile Strength ASTM D638 3,000 psi

   2.04 FOLDED AND FORMED POLYETHYLENE LINER PIPE

   A. The pipe for lining shall comply with ASTM F-1533-94, minimum DR32.5.

   B. The sewer liner pipe and fittings shall be manufactured from high density polyethylene pipe compound which conforms to ASTM D1248 and meets the requirements for Type PE3408, Class C or E product.

   C. Pipe made from this compound must have a long-term hydrostatic strength rating of 1600 psi or more, in accordance with ASTM D2837.

   D. When the environmental stress crack resistance (ESCR) of the compound is measured in accordance with ASTM D1693, Condition C, the compound shall withstand not less than 192 hours in 100% solution Igepal CO-630 at 100 degrees F before reaching a 20% failure point (F20).

   E. Tests for compliance shall be made according to the applicable ASTM specification. A certificate with this specification shall be provided by the manufacturer for all material furnished. The Owner reserves the right to witness inspection and test of the materials.

   F. The outside diameter and minimum wall thickness shall be furnished to a size that when installed will neatly fit (minimum 97.5%) the internal circumference of the existing conduit. Allowance shall be made for misaligned and missing conduit, if present. Standard dimension ratio of liner shall be based on the flow capacity, external loads (hydrostatic pressure and/or static and dynamic earth loads), and internal pressure, if applicable.

   G. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet to the outlet of the respective manholes unless otherwise specified. The Contractor shall verify the lengths in the field before manufacturing. Individual insertion runs can be made over one or more manhole sections as determined in the field by the Engineer and approved by the Owner.

   H. The liner pipe shall conform to the minimum structural standards for HDPE (Type III Resins) meeting ASTM D-3350, as listed below.

   U.S. Standard Results

   Flexural Stress (Yield) ASTM D-638 3,300 psi

   Flexural Stress (Break) ASTM D-638 4,500 psi

   Flexural Modulus of

   Elasticity ASTM D-790 145,000 psi

   2.05 POLYETHYLENE LINER PIPE FOR SLIPLINING

   A. The sewer liner pipe and fittings shall be manufactured from high density polyethylene pipe compound which conforms to ASTM D1248 and meets the requirements for Type III, Class B, Category 5, grade P34 and has a PPI rating of PE3408. The pipe produced from this resin shall have a minimum cell classification of 345434D or E (inner wall shall be light in color to produce good quality VHS tapes from TV inspection) under ASTM D3350.

   B. Pipe made from this compound must have a long-term hydrostatic strength rating of 1600 psi or more, in accordance with ASTM D2837.

   C. When the environmental stress crack resistance (ESCR) of the compound is measured in accordance with ASTM D1693, Condition C, the compound shall withstand not less than 192 hours in 100% solution Igepal CO-630 at 100 degrees F before reaching a 20% failure point (F20).

   D. Tests for compliance shall be made according to the applicable ASTM specification. A certificate with this specification shall be provided by the manufacturer for all material furnished. The Owner reserves the right to witness inspection and test of the materials.

   E. The outside diameter of the liner shall be 8.625 inches with a standard dimension ratio (SDR) of 21 for insertion into a nominal 18 inch internal diameter existing sewer pipe.

   F. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet to the outlet of the respective manholes unless otherwise specified. The Contractor shall verify the lengths in the field before manufacturing.

   G. The liner pipe shall conform to the minimum structural standards for HDPE (Type III Resins) meeting ASTM D-3350-84, as listed below.

   U.S. Standard Results

   Flexural Stress (Yield) ASTM D-638 3,300 psi

   Flexural Stress (Break) ASTM D-638 4,500 psi

   Flexural Modulus of

   Elasticity ASTM D-790 145,000 psi

   2.06 POLYVINYL CHLORIDE SLIP-LINER PIPE

   A. The sewer liner pipe and fittings shall be in conformance with Section 02730 - 2.02.A.

   B. The liner shall have a standard dimension ratio (SDR) of 35 for insertion into a nominal 18 inch internal diameter existing sewer pipe.

   C. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet to the outlet of the respective manholes unless otherwise specified. The Contractor shall verify the lengths in the field before manufacturing.

   2.07 FOLDED AND FORMED POLYVINYL CHLORIDE (PVC) LINER PIPE

   A. The pipe for lining shall comply with ASTM F1504-96, minimum DR35.

   B. The sewer line pipe and fittings shall be manufactured from PVC compound which conforms to ASTM D1784 classification 12334-B or 12344-B, 13223-B. Compounds that have different cell classifications because one or more properties are superior to those of the specified compounds are also acceptable.

   C. Dimension ratio calculations will use a modulus reduction of at least 50% for long term (50 year) creep.

   D. Tests for compliance shall be made according to the applicable ASTM specification. A certificate with this specification shall be provided by the manufacturer for all material furnished. The Owner reserves the right to witness inspection and test of the materials.

   E. The outside diameter and minimum wall thickness shall be fabricated to a size that when installed will neatly fit (minimum 97.5%) the internal circumference of the existing conduit. Allowance shall be made for misaligned and missing conduit if present. Standard dimension ratio of liner shall be based on the flow capacity, external loads (hydrostatic pressure and/or static and dynamic earth loads), and internal pressure if applicable.

   F. The minimum length shall be that deemed necessary by the Contractor to effectively span the distance from the inlet of the respective manholes unless otherwise specified. The Contractor shall verify the lengths in the field before manufacturing. Individual insertion runs can be made over one or more manhole sections as determined in the field by the Engineer and approved by the Owner.

   G. The liner pipe shall conform to the following minimum structural standards:

   U.S. STANDARD RESULTS

   Flexural Modulus

   of Elasticity ASTM D790 280,000 psi

   Tensile Strength ASTM D638 5,000 psi

   "Softening" Temperature ASTM D883 140ºF

   2.08 EXPANDING HYDROPHILIC RUBBER JOINT SEAL

   A. The rubber joint seal shall be an extended hydrophilic rubber compounded from chloroprene (Neoprene) rubber and an hydrophilic resin, which expands on contact with water.

   B. The rubber joint seal shall be bonded with adhesive on one face to hold it in place during assembly.

   C. On contact with water, the rubber shall swell by up to 10 times its original volume if necessary and mold itself to completely fill any gaps and exert pressure evenly to ensure the seal. High compression or bolt up forces shall not be necessary to effect a complete and watertight seal.

   PART 3 - EXECUTION

   3.01 PREPARATION

   A. The following installation procedures shall be adhered to unless otherwise approved by the Owner's representative.

   1. The Contractor shall carry out his operations in strict accordance with all OSHA and manufacturer's safety requirements. Particular attention is drawn to those safety requirements involving entering confined spaces.

   2. It shall be the responsibility of the Contractor to remove all internal debris and clean the existing sewer line prior to installation of the liner. Cleaning and disposal of material shall be performed in conformance with Section 02762 - Sanitary Sewer Cleaning and Inspection.

   3. Inspection of existing sewer lines shall be performed by experienced personnel trained in locating breaks, obstacles and service connections by closed circuit television. The interior of the line shall be carefully inspected to determine the location of any conditions which may prevent proper installation of the liner pipe into the lines, and such conditions shall be noted so they can be corrected. A video tape and suitable log shall be kept for later reference by the Owner as specified in Section 02762 - Sanitary Sewer Cleaning and Inspection.

   4. The Contractor shall provide for the flow of sewage around the section or sections of pipe designated for lining as specified in Section 02767- Sewer Flow Control.

   5. The Contractor shall clear the line of obstructions such as solids, dropped joints, protruding service connections or collapsed pipe that will prevent the insertion of the liner pipe, as noted on the Drawings and TV Logs attached. If inspection reveals an obstruction that cannot be removed by conventional sewer cleaning equipment, then the Contractor shall make a point repair excavation to uncover and remove or repair the obstruction.

   6. Hydrophilic rubber joint seals shall be installed at all manhole walls for all lining products.

   7. All manholes where a liner is installed shall be rehabilitated in accordance with Section 02765 - Sanitary Sewer Manhole Rehabilitation.

   8. Ground water temperatures and ambient temperatures shall not be excessive for the product installation procedures.

   9. Where practicable, liners should be installed in continuous runs where there are two or more continuous manhole segments. This is especially desirable to connect several short manhole segments with a continuous lining.

   3.02 INSTALLATION

   A. POLYETHYLENE LINER PIPE/PIPE BURSTING:

   1. Where excavations for insertion of the polyethylene liner are made in a line section between two manholes, the Contractor will establish the excavation points on the basis of location of the lines to be sliplined, pushing distances, and traffic conditions. The locations of the excavation points should be such as to minimize traffic disruption. The insertion pit(s) shall be long enough to avoid imposing a bending radius of less than 35 times the outside diameter of the pipe liner during insertion. The insertion pit(s) shall be sloped gradually from the ground surface to the top of the sewer. The width of the insertion pit(s) shall be sufficient to allow the entry of the workmen. Sheathing and bracing requirements will depend on depth and ground conditions and the Contractor shall determine the necessity for such sheathing and bracing. The top of the existing sewer line shall be exposed to the spring line and the crown of the pipe shall be removed as necessary for insertion of the liner. Care shall be taken not to disturb the bottom portion of the existing sewer line. Manhole replacement excavations shall be used unless otherwise approved.

   2. Sections of polyethylene pipe shall be assembled and joined together prior to insertion of the pipe. Assembly shall be accomplished above ground, either at the job site or a remote location.

   3. Joining for polyethylene shall be accomplished by the thermal butt fusion method, in strict accordance with the manufacturer's recommendations and in accordance with applicable specifications of ASTM D2657. All fusion joining shall be performed by trained personnel with equipment designed for butt fusion of thermoplastic pipe. Joining of the liner, in cases where the insertion pit is not at a manhole, may be accomplished by use of a stainless steel, reinforced full-encirclement clamp or the installation of a new manhole. Table II details the recommended minimum lengths of such clamps to afford adequate pullout protection.

    TABLE II

    OD of the Minimum Length

    Liner Pipe of Clamp

    (inches) (inches)

    8.625 15

   4. Alternate methods of joining shall be subject to approval by the Engineer.

   5. The liner shall be inserted into the existing sewer line and advanced by a pneumatic or hydraulic powered pipe bursting head. Powered winches may be used to assist the pipe bursting head travel. The rate of travel shall be in accord with the manufacturer recommendations and field conditions. Length of the liner pipe to be inserted at any one time shall be governed by the power available and consideration of the size and condition of the sewer.

   6. During insertion, precautions should be taken to protect the liner pipe to prevent the ragged edges of the broken sewer pipe from scoring the outside of the liner as it is being pushed into the sewer.

   7. The manufacturer's recommendations should be followed regarding relaxation of the liner prior to sealing the annular space between the liner and the existing sewer pipe at the manholes.

   8. In those places where the entrance shaft is excavated at an existing manhole, the manhole shall be repaired or it shall be replaced with a new manhole conforming to the specifications for manhole construction and in accordance with the Engineering Drawings.

   9. Foam sealant should not protrude into the manhole and should be finished over with a quick-set, nonshrink type of cement grout. Finishing inside the manhole shall be accomplished using a quick-set cement type grout to raise the manhole trough to the invert of the liner pipe. Only the upstream seal should be made prior to connecting services.

   10. After the liner has been secured in the upstream manhole area, each existing service connection shall be excavated and reconnected to the new liner. A portion of the existing sewer, at the liner pipe, around each service connection shall be removed to expose the liner pipe to provide adequate working space for making the new service connection. Service laterals shall be connected to the liner pipe using either polyethylene heat fusion saddles or strap-on saddles as conditions require or as specified. Strap-on saddles shall be secured to the liner pipe using stainless steel bands. A neoprene gasket shall be inserted between the liner and the strap-on saddle.

   11. Connections of the saddle fittings to the existing lateral shall be made using elastomeric boots, full-encirclement clamps, or by other methods approved by the Engineer.

   12. Backfill all excavations as specified in Section 02220 - Excavation, Backfilling, Compaction.

   13. The contractor shall replace all manholes where the PE liner is continuous in a minimum of two (2) directions, and where the sewer terminates, or as indicated on the drawings. Manholes replaced shall be considered as rehabilitated under this method and treatments under Section 02765 - Sanitary Sewer Manhole Rehabilitation are not required. Payment will be made under the manhole rehabilitation item for replaced manholes.

   B. CURED-IN-PLACE LINER:

   1. The Contractor shall designate a location where the reconstruction tube will be vacuum impregnated prior to installation. The Contractor shall allow the Owner to inspect the materials and "wet out" procedure. A catalyst system compatible with the resin and reconstruction tube shall be used. Sufficient excess resin will be provided to insure a mechanical bond with the host pipe after curing.

   2. The wet out reconstruction tube shall be inserted through an existing manhole or other approved access by means of an inversion process and the application of a hydrostatic head sufficient to fully extend it to the next designated manhole or termination point. The reconstruction tube shall be inserted into the vertical inversion standpipe with the impermeable plastic membrane side out. At the lower end of the inversion standpipe, the reconstruction tube shall be turned inside out and attached to the standpipe so that a leak-proof seal is created. The inversion head will be adjusted to be of sufficient height to cause the impregnated tube to invert from manhole to manhole and hold the tube tight to the pipe wall, produce dimples at side connections and flared ends at the manholes. The use of a lubricant is recommended. Care shall be taken during the elevated curing temperature so as not to overstress the felt fiber. Alternative methods of liner insertion and pressurization may be used for products and processes approved by the State of Tennessee Department of Environment and Conservation and when the final cured-in-place product meets the intent of ASTM F1216. Installation shall be in accordance with manufacturer's recommendations which shall be available for verification by the inspector.

   3. After inversion is completed the Contractor shall supply a suitable heat source and water recirculation equipment. The equipment shall be capable of delivering hot water throughout the section by means of a prestrung hose to uniformly raise the water temperature above the temperature required to effect a cure of the resin. This temperature shall be determined by the resin/catalyst system employed.

   4. The heat source shall be fitted with suitable monitors to gauge the temperature of the incoming and outgoing water supply. Another such gauge shall be placed between the impregnated reconstruction tube and the pipe invert at the remote manhole to determine the temperatures during cure. Water temperature in the line during the cure period shall be recommended by the resin manufacturer.

   5. Initial cure shall be deemed to be completed when inspection of the exposed portions of cured pipe appear to be hard and sound and the remote temperature sensor indicates that the temperature is of a magnitude to realize an exotherm. The cure period shall be of a duration recommended by the resin manufacturer, as modified for the cured-in-place inversion process, during which time the recirculation of the water and cycling of the heat exchanger to maintain the temperature continues.

   6. The Contractor shall cool the hardened pipe to a temperature below 100 degrees F before relieving the static head in the inversion standpipe. Cool-down may be accomplished by the introduction of cool water into the inversion standpipe to replace water being drained from a small hole made in the downstream end. Care shall be taken in the release of the static head so that a vacuum will not be developed that could damage the newly installed pipe. The discharge water temperature shall not exceed the level allowed by State or local standards.

   7. The finished pipe shall be continuous over the entire length of an inversion run and be as free as commercially practicable from visual defects such as foreign inclusions, dry spots, pinholes and delamination. It shall also meet the leakage requirements or pressure test specified below.

   8. If due to broken or misaligned pipe at the manhole wall or other reason the new pipe liner fails to make a tight seal, the Contractor shall apply a seal at that point. The seal shall be of a resin mixture compatible with the pipe.

   9. After the new pipe has been cured in place, the Contractor shall renew (reestablish or reinstate) the existing active service connections. This shall be done without excavation in pavement areas, and in the case of nonman-entry pipes, from the interior of the pipeline by means of a 3600 television camera and a cutting device that reestablishes the service connection. If a remote cutting device is used and a cleanout is available, then a mini-camera down the service shall also be used to assist the operator in cutting or trimming. Services in a segment receiving a cured-in-place lining shall generally be renewed before the main line is lined by a similar method as for main line to or from an inspection tee installed at the property line or easement line by the Contractor. Services connected to a manhole, which is an entry, exit, or intermediate manhole for lining, shall be renewed as stated above.

   10. Services outside of pavement areas and where the inspection tee is within 10 L.F. of the liner pipe centerline or less than 10' deep may be replaced with approved epoxied-on-saddle and 6" PVC pipe to the inspection tee per Section 02763 - Gravity Sewer Rehabilitation .

   11. Services inside of pavement areas may be excavated and replaced if the connection area conditions prohibit service lining on an individual approval basis. No additional compensation will be allowed.

   C. FOLDED AND FORMED POLYETHYLENE LINER PIPE:

   1. The polyethylene liner shall be inserted into the existing sewer line with a power winch and steel cable connected to the end of the liner by use of an appropriate pulling head. A second pulling head may be attached to the other end of the liner for attachment of a tag line to pull the liner back out of the sewer line, if necessary. Length of the liner pipe to be inserted at any one time shall be governed by the winch drum capacity and winching power available and consideration of the size and condition of the sewer.

   2. During insertion, the Contractor shall take necessary precautions to protect the liner pipe to prevent scoring the outside of the liner as it is being pulled into the sewer.

   3. After insertion is completed, the Contractor shall supply a suitable heat/pressure source and water recirculation equipment. The equipment shall be capable of delivering hot water/pressure throughout the section to uniformly raise water temperature required to reform the liner.

   4. The heat source shall be fitted with suitable monitors to gauge the temperature of the incoming and outgoing water supply.

   5. The Contractor shall cool the liner to a temperature below 100 degrees F before relieving the reforming pressure. Cool-down may be accomplished by the introduction of cool water or other approved method into the recirculation network.

   6. The finished liner shall be continuous over the entire length of the insertion and be as free as commercially practicable from the visual defects such as foreign inclusions.

   7. Seal the area where the line enters or leaves each manhole. Finish the inside of the manhole with a quick set cement grout to raise the invert to the grade of the liner pipe. Also use this grout to dress up around the end of the liner. This space may be sealed with a mechanical seal, chemical seal, or combination of both. The chosen method must be approved by the Engineer.

   8. If due to broken or misaligned pipe at the manhole wall or other reason the pipe liner fails to make a tight seal, the Contractor shall apply a seal at that point. The seal shall be approved by the Engineer.

   9. After the liner has been reformed in place, the Contractor shall reconnect and renew the existing active service connections. The methods of reconnection shall be:

   a) Excavate and reconnect thorough use of a heat fusion polyethylene stub or strap-on Neoprene Gasket Saddle as conditions require from the exterior of the liner and as directed by Engineer. The stubout attached to the saddle must protrude into the polyethylene liner in place but not protrude into the liner pipe interior. Attach the stubout to the service line with a reinforced compression coupling.

   b) Enter the liner from within by means of a 3600 television camera and a cutting device that reestablishes connections to no less than 90% capacity,

   c) Man entry using a hand held tapping devise.

   10. When exterior taps are made, connections of the saddle fittings or fused stubs to the existing lateral shall be made using full encirclement clamps, or by other methods specified by the Engineer. "Insert-A-Tees" shall not be used.

   11. At all points where the liner pipe has been exposed (e.g., in access shafts, service connections, etc.), prepare for the placement of a crushed stone backfill by removing all debris and creating a void below and around the pipe. The width of this void shall not exceed 4/3 of the liner's outside diameter plus 15", or 4/3 of the service line's outside diameter plus 15". Use a minimum of 6" of 1/2" to 3/4" crushed stone to provide bedding for the liner and service line. Then place a backfill of crushed stone to a height of 6" above the liner and service line. Provide the rest of the backfill from 6" above the pipe to grade as specified in Section 02220 - Excavation, Backfilling, Compaction. Replace pavement removed during excavation in accordance with the requirements of Section 02514 - Portland Cement Concrete Paving as applicable.

   12. Renew all service connections to the property line or easement line per Section 02763 - Gravity Sewer Rehabilitation, including inspection tees with 6-inch PVC pipe. Services connected to a manhole, which is an entry, exit, or intermediate manhole for lining, shall be renewed.

   13. When directed by the Engineer to reconnect and renew service by internal means only, the main/service connection shall be sealed with materials and by a method, such as urethane grouting, approved by the Engineer.

   D. FOLDED AND FORMED PVC LINER PIPE

   1. The PVC liner pipe shall be manufactured in the folded shape and spooled in a continuous length for storage and shipping to the job site.

   2. Apply hydrophilic rubber joint seal around each end of the section of pipe to be reconstructed.

   3. At the job site, a heat containment tube may be pulled through the pipe to be reconstructed and inflated with air.

   4. The spool of folded PVC liner pipe shall be heated to make the PVC liner pipe flexible for insertion into the existing pipe.

   5. A cable shall be strung through the existing pipe and attached to the folded PVC liner pipe. The PVC liner pipe shall then be inserted into the existing pipe through an existing manhole or access point.

   6. After it is inserted into the existing pipe, the folded PVC pipe is cut off at the starting point and restrained at the terminating point.

   7. Through the use of steam and a specially designed pressure-driven rounding device, the folded PVC liner pipe is rounded and pressed tightly against the existing pipe wall in a progressive manner from the starting point to the terminating point in such a manner as to eliminate the probability of trapping any entering of standing water. This process also forms dimples in the PVC liner pipe at service connections.

   8. The installer shall cool the PVC liner pipe to a temperature as directed by the manufacturer before relieving the pressure required to hold the PVC liner pipe against the existing pipe wall.

   9. After the pressure is relieved from the PVC liner pipe, the installer shall reestablish the existing active service connections. This shall generally be done without excavation, from the interior of the pipeline by means of a 3600 television camera and a remotely controlled cutting device that reestablishes the service connection.

   10. Renew all service connections to the property line or easement line per Section 02763 - Gravity Sewer Rehabilitation, with epoxyed saddles, including inspection tees with 6-inch PVC pipe. "Insert-A-Tees" shall not be used. Services connected to a manhole, which is an entry, exit, or intermediate manhole for lining, shall be renewed.

   11. If due to broken or misaligned pipe at the manhole wall or other reason the new pipe liner fails to make a tight seal, the Contractor shall apply a seal at that point. The seal shall be of a resin mixture compatible with the pipe.

   12. At all points where the liner pipe has been exposed (e.g., in access shafts, service connections, etc.), prepare for the placement of a crushed stone backfill by removing all debris and creating a void below and around the pipe. The width of this void shall not exceed 4/3 of the liner's outside diameter plus 15", or 4/3 of the service line's outside diameter plus 15". Use a minimum of 6" of 1/2" to 3/4" crushed stone to provide bedding for the liner and service line. Then place a backfill of crushed stone to a height of 6" above the liner and service line. Provide the rest of the backfill from 6" above the pipe to grade as specified in Section 02220 - Excavation, Backfilling, Compaction. Replace pavement removed during excavation in accordance with the requirements of Section 02514 - Portland Cement Concrete paving as applicable.

   13. When directed by the Engineer to reconnect and renew service by internal means only, the main/service connection shall be sealed with materials and by a method, such as urethane grouting, approved by the Engineer.

   E. POLYETHYLENE OR PVC SLIP-LINER PIPE:

   1. Where excavations for insertion of the polyethylene or PVC liner are made in a line section between two manholes, the Contractor will establish the excavation points on the basis of location of the lines to be sliplined, pushing distances, and traffic conditions. The locations of the excavation points should be such as to minimize traffic disruption. The insertion pit(s) shall be long enough to avoid imposing a bending radius of less than 35 times the outside diameter of the pipe liner during insertion. The insertion pit(s) shall be sloped gradually from the ground surface to the top of the sewer. The width of the insertion pit(s) shall be sufficient to allow the entry of the workmen. Sheathing and bracing requirements will depend on depth and ground conditions and the Contractor shall determine the necessity for such sheathing and bracing. The top of the existing sewer line shall be exposed to the spring line and the crown of the pipe shall be removed as necessary for insertion of the liner. Care shall be taken not to disturb the bottom portion of the existing sewer line. Service renewal excavations shall be used unless otherwise approved.

   2. Sections of polyethylene pipe shall be assembled and joined together prior to insertion of the pipe. Assembly shall be accomplished above ground, either at the job site or a remote location.

   3. Joining for polyethylene shall be accomplished by the thermal butt fusion method, in strict accordance with the manufacturer's recommendations and in accordance with applicable specifications of ASTM D2657. All fusion joining shall be performed by trained personnel with equipment designed for butt fusion of thermoplastic pipe. Joining of the liner, in cases where the insertion pit is not at a manhole, may be accomplished by use of a stainless steel full-encirclement clamp or the installation of a new manhole. Table II details the recommended minimum lengths of such clamps to afford adequate pullout protection.

    TABLE II

    OD of the Minimum Length

    Liner Pipe of Clamp

    (inches) (inches)

    8.625 15

   4. Alternate methods of joining shall be subject to approval by the Engineer.

   5. The liner shall be inserted into the existing sewer line by pushing in order to eliminate the possibility of shrinkage during relaxation after the pipe is installed. Length of the liner pipe to be inserted at any one time shall be governed by the power available and consideration of the size and condition of the sewer.

   6. During insertion, precautions should be taken to protect the liner pipe to prevent the ragged edges of the broken sewer pipe from scoring the outside of the liner as it is being pushed into the sewer.

   7. Spacers shall be banded unto the liner pipe at 8-foot intervals to prevent flotation during grouting, or other undesirable movement. The spacers shall be graduated in size to establish the grade slope inside the 18-inch host pipe as shown on the plans.

   8. The manufacturer's recommendations should be followed regarding relaxation of the liner prior to sealing the annular space between the liner and the existing sewer pipe at the manholes.

   9. In those places where the entrance shaft is excavated at an existing manhole, the manhole shall be repaired or it shall be replaced with a new manhole conforming to the specifications for manhole construction and in accordance with the Engineering Drawings.

   10. Foam sealant should not protrude into the manhole and should be finished over with a quick-set, nonshrink type of cement grout. Finishing inside the manhole shall be accomplished using a quick-set cement type grout to raise the manhole trough to the invert of the liner pipe. Only the upstream seal should be made prior to connecting services.

   11. The entire annular space between the existing pipe and the liner shall be filled with non-shrink grout. Precautions shall be taken to prevent collapsing the liner with grouting pressure. Either place the grout under very low pressure, or hydrostatically pressurize the liner during the grouting procedure to resist collapse.

   12. After the liner has been secured in the upstream manhole, each existing active service connection shall be excavated and reconnected to the new liner. A portion of the existing sewer, at the liner pipe, around each service connection shall be removed to expose the liner pipe to provide adequate working space for making the new service connection. Service laterals shall be connected to the liner pipe using either polyethylene heat fusion saddles or strap-on saddles as conditions require or as specified. Strap-on saddles shall be secured to the liner pipe using stainless steel bands. A neoprene gasket shall be inserted between the liner and the strap-on saddle.

   13. Connections of the saddle fittings to the existing lateral shall be made using elastomeric boots, full-encirclement clamps, or by other methods approved by the Engineer.

   14. Backfill all excavations as specified in Section 02220.

   3.03 POST INSTALLATION

   A. After installation of folded and formed polyethylene liner pipe (DPE) or folded and formed PVC liner pipe (DPVC), a minimum of 6 inches of the liner material shall be left to protrude from the wall of the entrance and the exit manhole prior to relaxation. A 48 hour relaxation period (or longer if recommended by the manufacturer) shall be required to allow the liner to stabilize in its rerounded condition. After the relaxation period, the protruding ends in the exit and entrance manholes shall be neatly trimmed back to the manhole wall and allow a slight flaring of the material at the wall so that the liner will not pull away from the opening and retract into the original pipe.

   B. Where liners of any type are installed in two or more continuous manhole segments, the liner invert through the intermediate manholes shall be left intact. Final finishing of the installation in those intermediate manholes shall require removal of the top of the exposed liner and neat trimmings of the liner edge where it touches the lip of the manhole bench.

   C. Portions of any piece of liner material removed during installation shall be available for inspection and retention by the Owner or the Engineer.

   D. Outside drop appurtenances shall be reinstated after curing.

   E. Each line segment lined shall be TV inspected as soon as practical after curing.

   F. For cured-in-place lined services, each service shall be televised within 24 hours of lining with a mini-camera through the inspection tee to verify full opening, and no liner collapse.

   3.04 TESTING

   A. After installation every liner shall be TV inspected with a 3600 integral lighthead camera as soon as practical to verify proper installation. The rate of travel shall not exceed 30 feet per minute. At each service, the camera shall come to a complete stop and the service shall be panned. The footage meter count shall be clearly visible. Perform a test on the sewer line as specified below.

   B. After installation the Contractor shall run a test on the sewer line to determine if it is watertight, including renewed services to the inspection tee.

   1. The Contractor shall furnish all necessary equipment to conduct the test. An acceptable method is a low-pressure air test, conducted as follows:

   2. Pressurize the test section to 4.0 psi and hold above 3.5 psi for not less than 2 minutes. Add air if necessary to keep the pressure above 3.5 psi. At the end of this 2-minute stabilization period, note the pressure (must be 3.5 psi minimum) and begin the timed period. If the pressure drops 0.5 psi in less than the time given in the table below, the section of pipe shall have failed the test.

   3. When the prevailing groundwater is above the sewer being tested, test pressure shall be increased 0.43 psi for each foot that the water table is above the invert of the sewer.

    Sewer Size Minimum Test Time/100 ft.

    (Inches) (Seconds)

    8 72

    10 90

    12 108

    15 126

    18 144

    21 180

    24 216

    27 252

    30 288

   4. If the time for the pressure to drop 0.5 psi is 125 percent or less of the time given in the table, the line shall immediately be re-pressurized to 3.5 psi and the test repeated.

   5. Building sewers reinstated before the air test shall be considered part of the pipe to which they are connected and no adjustment of test time shall be allowed.

   6. The pressure gage used shall be supplied by the Contractor and have minimum divisions of 0.10 psi and be oil filled.

   C. At the manhole connections, no visible leaks around the liner shall be allowed.

   D. Polyethylene liners installed by pipe bursting shall be mandrelled after 30 days.

   3.05 CLEANUP

   A. After the installation work has been completed and all testing acceptable, the Contractor shall clean up the entire project area and return the ground cover to grade. All excess material and debris not incorporated into the permanent installation shall be disposed of by the Contractor. Easement sidewalks, driveways, and street surfaces shall be restored as specified or to the original condition.

   3.06 PATENTS

   A. The Contractor shall warrant and save harmless the Owner and Engineer against all claims for patent infringement and any loss resulting therefrom.

   3.07 PRIVATE SERVICE LINE SHUTDOWN

   A. When it is necessary to shutdown a private sewer service line while work is in progress and before the service lines are reconnected, the residents are to be notified by the Contractor at least one week prior to the shutdown. No sewer or water service is to remain shutdown for more than a period of eight (8) hours unless the Contractor provides substitute services for the residents. Commercial sewer services shall be maintained at all times the business is open. No sewage from the services or main line shall be allowed to be discharged on the ground or in waterways. Holding pits or tanks are not allowed unless permitted by TDEC.

   3.08 PROSECUTION OF WORK

   A. The Contractor is cautioned that only those sewer services that are live and active shall be repaired, or reinstated after the sewer main has been lined or replaced due to defects. The Contractor shall note that not all sewer lines segments have been televised in their entirety due to obstructions blocking further entry, etc. These obstructions shall be cleared to allow TV viewing of the entire segment length before lining is commenced. Several sewer line segments may contain an excessive number of services for the dwellings served. The Contractor shall determine through dye testing, or other acceptable methods, the services that are live and require reinstatement prior to commencing lining of the sewer main. Services that are inactive, but reinstated, shall be plugged at the Contractor's expense.

    END OF SECTION

Rembco Geotechnical Contractors specializes in slope stabilization, foundation repair and support, shoring, grouting, soil nails, micropile installations, and sinkholes. We are experienced in these applications: micro piles, sinkhole repair, permeation grouting, pressure grouting, soil nails, chemical grouting, micropiles, compaction grout, rock anchors and compaction piles. Our specialties are rock anchor, chemical and compaction grouting, mini piles, sinkhole repair, micropiles, and soil nailing. We use a problem-solving approach in the geotechnical portions of buildings, bridges, water plants, sewage plants, tunnels, sinkholes, caisson, and roads. Rembco techniques apply when adding new real estate structures: especially rock anchor, microfine grouting, soil nailing, micropile installations for foundation support. Add URL Construction, Drilling and Concrete