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    SECTION 02764

    INTERNAL POINT REPAIRS TO SANITARY SEWERS

   PART 1 - GENERAL

   1.01 SECTION INCLUDES

   A. Internally rehabilitating certain portions of the existing sewer system at a specific point, including collection lines, service lines, and service connections, without excavation, wherever the bidding instruments indicate that this is to be done. Control the existing flow in the line segment being replaced whenever necessary during replacement. The materials used for rehabilitation shall be either CIP lining products or two part epoxy resin injection systems as set forth in the Bid Form and as specified below.

   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:

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

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

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

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

   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 including time and duration of water and sewer service unavailability.

   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. All materials shall be in strict compliance with the required standards and specifications of ASTM, ANSI, and/or AWWA.

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

   C. The finished pipe liner or epoxy resin in place shall be fabricated from materials which when complete is chemically resistant to and will withstand internal exposure to domestic sewage.

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

   2.02 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 adjacent pipe joints plus 1.0 feet each side 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 0638 3,000 psi

   2. The liner thickness shall be sized for a minimum hydrostatic load of 8.0 feet and the maximum depth of earth cover as shown on the plans. The hydrostatic load shall be increased to manhole depth plus 1.0 foot for bury depths in excess of 8.00 feet.

   F. Corrosion Requirements:

   The cured pipe will be chemically resistant to internal exposure of sewage having a pH range of 5 to 11 and a peak temperature of 1800F.

   2.03 TWO PART EPOXY RESIN INJECTION SYSTEM

   A. The two part epoxy resin shall adhere to dry or wet surface, and be able to cure under water without the presence of air. The epoxy resin set time shall be from one to eight hours and have sufficient strength to restore and structural integrity of the pipe when cracked, broken, or joint deteriorated. The epoxy cement resin used shall be SikaRobotec-56, by Master Builders, Inc. or approved equal. The epoxy shall adhere to concrete, clay, brick, asbestos cement, mineral fibre cement and metal. It shall form an adhesive epoxy mortar for repair or structural defects. The epoxy shall be solvent free, water proof, harden without shrinking, resist vibration, and have high resistance to abrasion.

   B. The material shall reach its initial curing strength at 8 hours and final strength in 7 days. The mix ratio shall be 100:30 by weight.

   Physical properties: the fully cured material shall conform to the following minimum structural stands.

   Compressive strength 50-55 N/MM 7252-7977 PSI

   Flexural strength 20-25 N/MM 2901-3626 PSI

   Modulus of elasticity 2800 N/MM 406,106 PSI

   C. Hastelloy®sheets ranging in thickness from 0.0196" to 0.0397" and by approximately 17" in length shall be used to replace missing sections of pipe whenever possible. The Hastelloy shall be resistant to hydrogen sulphide gasses and deterioration from sewage.

   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.

   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 or epoxy injection 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.

   4. The Contractor shall provide for the flow of sewage around the section or sections of pipe designated for internal point repairs as specified in Section 02767.

   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 materials or equipment, as noted on the Drawings and TV Logs attached. If inspection reveals an obstruction that cannot be removed by conventional sewer cleaning equipment or robotec equipment, then the Contractor may be ordered to make a point repair excavation to uncover and remove or repair the obstruction.

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

   3.02 INSTALLATION

   A. 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 and the application of a hydrostatic head sufficient to fully extend it to the termination point. The head will be adjusted to be of sufficient height to 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 insertion 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. 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 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 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. Cool-down may be accomplished by the introduction of cool water 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, wrinkles, dry spots, pinholes and delamination. It shall also meet the leakage requirements or pressure test specified below.

   B. Two Part Epoxy Resin Injection System:

   1. A robotec preparation device shall be introduced into the sewer line. The robot shall be self propelled and positioned at the point of repair in sewer lines of 8" through 30" I.D.

   2. Joint repair shall begin by milling and drilling into the joint to a sufficient depth to open, clean, and remove all loose pipe surface. The process shall properly prepare all surface areas where the epoxy is to adhere. No epoxy shall be injected into joints that have not been properly milled to remove the glaze or to a depth of 1/32".

   3. The epoxy shall be injected under sufficient pressure to assure complete penetration. After curing, the epoxy surface shall be sanded or ground to insure a smooth surface and pipe diameter reduction not to exceed 1/8" inside diameter.

   4. Broken, crushed, and cracked pipe shall be mailed open to the maximum possible pipe diameter. This will include milling off of uneven surface and jagged edged. The longitudinal and circumferential cracks shall be drilled open and milled to sufficient depth and width (min. 1") to open, clean and remove all loose pipe surface. The process shall properly prepare all surface areas where the epoxy is to adhere. No epoxy shall be injected on pipe surface that has not been milled to remove the glaze or to a depth of 1/32". The epoxy shall be injected under sufficient pressure to assure complete penetration, After curing, the epoxy surface shall be sanded or ground to insure a smooth surface. Pipe diameter reduction not to exceed 1/8" inside diameter.

   5. Missing pipe shall be replaced by inserting Hastelloy sheathing whenever possible. The pipe surface to be sheeted shall be prepared by removal of loose fragmented pipe pieces. The Hastelloy sheets shall be coiled onto the robot and coated with epoxy to an even thickness of 1/4". The robot shall be guided into the pipe to the point of repair and Hastelloy sheet will released. It shall form a new pipe inside the sewer line, Sufficient sheets shall be used to bridge the entire missing pipe sections. At the edge of the repairs, the milling or sanding tool will be used to smooth out rough epoxy. The inside diameter of the pipe shall not be reduced more than 1/2" after the insertion of the sheathing and the epoxy. This measurement will take into consideration the deformed diameter prior to the repair.

   6. Repair of lateral service connection shall be accomplished by milling off any protruding connection. The process shall properly prepare the surface for epoxy adhesion. The area around the service connection shall be filled with epoxy or troweled to a smooth surface. After injection under high pressure and subsequent curing, the repaired surface shall be sanded smooth. When the lateral connection required repair inside the lateral, a rubber inflatable plug will be wrapped with epoxy coated liner sleeve and inserted into the connection. The entire procedure will reconstruct the connection and terminate in a smooth repaired connection.

   7. All epoxy repair shall give structural support by the insertion of Hastelloy sheathing or by injection of the epoxy under high pressure through the defect area into, through and outside of the pipe. The repaired pipe and pipe joints will stop the infiltration of ground water and exfiltration of sewage into the water table. The repaired pipe and joints shall form a complete seal against root intrusion.

   3.03 POST INSTALLATION

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

   B. Each line segment lined shall be TV inspected as soon as practical after internal repair.

   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 internal point repair, the camera shall come to a complete stop and the area 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 internal point repair and the sewer line to determine if it is watertight.

   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 existing pipe/internal point repair interface, no visible leaks shall be allowed.

   3.05 EXISTING UTILITIES

   A. Carefully protect all existing sewers, water lines, gas lines, sidewalks, curbs, gutters, pavements, electric lines, or other utilities or structures in the vicinity of the work from damage at all times. Where it is necessary for the proper accomplishment of the work to repair, remove, and/or replace any such utility or structure, do so in accordance with the provisions set forth in the General and Special Conditions of these specifications. Any such work to be done at the Contractor's expense shall be considered incidental to the construction of sewers, and no additional payment will be allowed therefor.

   3.06 FIELD JUDGEMENT

   A. At any time during a repair, the Engineer may make field judgement that shall govern over the repair until such time that the specifications will again prevail.

   3.07 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.

   3.08 PATENTS

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

   3.09 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.

    END OF SECTION