02735 Cathodic Protection by keralaguest


									                        SPECIAL TECHNICAL PROVISION
                                SECTION 02735
                           CATHODIC PROTECTION



       The CONTRACTOR shall prepare installation shop drawings, furnish all
       materials, install all equipment, and provide all labor necessary to complete the
       work shown on the drawings and or/listed below and all other work and
       miscellaneous items not specifically mentioned but reasonably inferred, including
       all accessories and appurtenances required for a complete system. The intent of
       this specification is to provide for a complete, functional cathodic protection

       A.     Work included in this section consists of all installation shop drawings,
              components of the cathodic protection system, including zinc anodes,
              cables, and test stations, and any other work necessary to complete the

              1.     Provide installation shop drawings for all cathodic protection

              2.     Provide material submittals for all cathodic protection materials.

              3.     Obtain Engineer’s approval where required.

              4.     Provide quality control test procedures for approval.

              5.     Coating of steel and ductile iron piping.

              6.     Cathodic protection of coated steel and ductile iron pipe.

              7.     Installation of insulating fittings for isolation of pipelines.

              8.     Bonding of ductile iron and steel pipe and fittings.

              9.     Trenching, drilling, and other excavation.

              10.    Installation of zinc anodes, cables, and test stations.

              11.    Backfill and compaction of backfill.

              12.    Correction of all deficiencies.
                 13.    Cleanup and restoration of surface.

                 14.    Post-construction acceptance testing.


A.     General

       All work shall be performed to the satisfaction of METRO.

B.     Testing

       1.        Qualifications

                 The CONTRACTOR shall employ an independent corrosion control firm
                 to supervise installation and to perform all installation testing of the
                 corrosion control system including, but not limited to, the joint bonds and
                 external pipe coating. The independent corrosion control firm shall have
                 been continuously engaged in the field of corrosion control testing for a
                 minimum of five years and shall have the following qualifications:

                 a.     NACE International Certified cathodic protection specialists and
                        corrosion technicians available to perform the required field

                 b.     A minimum of five years experience in the testing of cathodic
                        protection systems for underground pipelines of similar type and
                        equal complexity as the system specified and indicated.

                 c.     Testing shall be performed by personnel with at least five years of
                        employment experience with testing corrosion control systems.

                 d.     All work to be performed under the direct supervision of a NACE
                        International Cathodic Protection Specialist.

                 e.     Provide a quality control test procedure which includes the
                        personnel to be utilized for the project, resumes and certifications,
                        data sheets, procedures, test equipment calibration certificates, and
                        all other pertinent data for approval by METRO.

                 f.     All test results shall be tabulated and submitted for review and
                        approval by METRO.

       2.        Electrical Continuity Testing of Bonded Pipe Joints
     a.     Electrical continuity tests shall be conducted on each joint bond
            wire with a Biddle Model 247001 digital low resistance ohmmeter.
            The resistance of each joint bond shall be measured in strict
            accordance with the meter manufacturer’s operating instructions.
            Use the probes to contact the pipe on each side of the joint, without
            touching the thermite weld connection or the wire. The contact
            area shall be cleaned to bright metal by filing and grinding without
            surface rusting or oxidation. Probe connections to the bond wire or
            thermite welds will not be acceptable. Record the measured joint
            bond resistance on the test form. Repair any damage to pipe
            coating incurred during testing.

     b.     No joint bond shall be accepted if the joint bond resistance is
            greater than 20% above the theoretical value of the pipe joint bond
            cables as calculated using the length of the bond cables multiplied
            by the unit resistance.

     c.     The CONTRACTOR shall replace any joint bonds that exceed the
            allowable resistance at his sole expense. Replacement joint bonds
            shall be retested for compliance with the specified bond resistance
            at the CONTRACTOR’s sole expense.

     d.     The CONTRACTOR shall protect the completed joint bond during
            the backfilling operation.

     e.     Records (data sheets) of each joint bond test shall be kept in a
            format acceptable to METRO and shall be transmitted to METRO
            within ten (10) days of the completion of the testing.

     f.     At METRO’s discretion, METRO’s representative will perform an
            overall continuity test at the end of the project. Any defective joint
            bonds, discovered during the testing, shall be located, uncovered,
            and repaired by the CONTRACTOR at his sole expense.

3.   Electrical Testing of External Pipe Coating

     a.      The external pipe coating shall be electrically tested for flaws
             immediately prior to the installation of the piping and/or fitting in
             the trench. The testing shall utilize a high-voltage holiday detector
             in accordance with NACE RP0274. All holidays detected shall be
             immediately repaired and the repaired coating shall be rechecked
             with the holiday detector. Once the coating is verified to be free of
             holidays, the piping may be installed in the trench. The electrical
             testing shall utilize a D. E. Stearns Model 14/20 Holiday Detector
             or approved equal.
4.   Electrical Isolation Testing of Insulating Couplings, Insulating Flanges,
             Insulating Unions, Insulating Fen-rules, and Insulating Casing Spacers

             a.     The electrical isolation of insulating couplings, insulating flanges,
                    insulating unions, and insulating casing spacers shall be
                    electrically tested to verify proper isolation. All defective isolation
                    components shall be repaired by the CONTRACTOR at no
                    additional cost to METRO. Records (data sheets) of each isolation
                    test shall be kept in a format acceptable to METRO and shall be
                    transmitted to METRO within ten (10) days of the completion of
                    the test.

             b.     Any defective insulating components, discovered during the testing
                    shall be located, uncovered, and repaired by the CONTRACTOR
                    at his sole expense.

       5.    Compaction

             a.     Compaction of backfill for anodes and trenches shall match the
                    existing conditions and shall be approved by METRO.


A.     At least 30 days prior to commencing installation work, the CONTRACTOR shall
       submit for approval by METRO, 6 copies of the following items in accordance
       with submittal procedures:

       1.    A complete list of cathodic protection equipment and material, including
             name and manufacturer, catalog number, size, finish, and any other
             pertinent data necessary for proper identification and to determine
             conformance with the specifications.

       2.    Certification by the cable manufacturer covering conformance of cable
             insulation to the designated specification.

       3.    A complete welding procedure for cable-to-pipe connection (weld
             connection process).

       4.    A certified test report showing the chemical analysis of all anodes.

       5.    A certified test report for anode backfill materials including chemical
             analysis, resistivity, and gradation.

       6.    Pipe coating and handling procedures shall be required and shall be
             submitted for approval.

       7.    A quality control test procedure as outlined in section 1.02-B-l-e.

A.     All buried pipe, valves, fittings, and appurtenances shall be dielectrically coated
       or tape wrapped.

B.     Galvanic cathodic protection shall be installed as shown on the drawings.

C.     All rubber gaskets, mechanical joints, and flexible couplings, excluding insulating
       components, shall be bonded along the entire pipeline, to provide complete
       electrical continuity along the length of each pipeline section.

D.     Test stations shall be installed, as shown on the drawings, to provide adequate test
       points for the measurement of electrical continuity, the measurement of electrical
       isolation at insulating joints, stray current measurements, and cathodic protection
       evaluation measurements. The test stations shall be installed at accessible


A.     NACE International (NACE):
       NACE RP0169 - Control of External Corrosion on Underground or Submerged
                      Metallic Piping Systems
       NACE RPOl00 - Cathodic Protection of Prestressed Concrete Cylinder Pipelines
       NACE R188 - Discontinuity (Holiday) Testing of Protective Coatings
       NACE RP0274 - High-Voltage Electrical Inspection of Pipeline Coatings
                      Prior to Installation
       NACE RP0286 - Electrical Isolation of Cathodically Protected Pipelines
       NACE RPO375 - Wax Coating Systems for Underground Piping Systems

B.     American Society of Testing and Materials (ASTM):
       ASTM Bl- Hard-Drawn Copper Wire
       ASTM D2655 - Standard Specification for Crosslinked Polyethylene Insulation
                      for Wire and Cable Rated 0 To 2000 V
       ASTM B4 18 - Standard Specification for Cast and Wrought Galvanic Zinc

C.     National Electrical Manufacturers Association (NEMA):
       NEMA 250 - Enclosures For Electrical Equipment (1000 Volts Maximum)

D.     American Society of Mechanical Engineers (ASME):
       ASME/ANSI B16.39 - Malleable Iron Threaded Pipe Unions 150,250,300PSI

E.     American Water Works Association (AWWA):
       ANSI/AWWA C209 - Cold-Applied Tape Coatings for the Exterior of Special
                          Sections, Connections, and Fittings for Steel Water
       ANSI/AWWA C214 - Tape Coating Systems for the Exterior of Steel Water
       ANSI/AWWA C2 15 - Extruded Polyolefin Coatings for the Exterior of Steel
                              Water Pipelines
       ANSI/AWWA C217 - Cold-Applied Petrolatum Tape and Petroleum Wax Tape
                              Coatings for the Exterior of Special Sections, Connections,
                              and Fittings for Buried Steel Water Pipelines
       ANSYAWWA Cl 16- American National Standard for Protective Fusion-Bonded
                              Epoxy Coatings for the Interior and Exterior Surfaces of
                              Ductile-Iron and Gray-Iron Fittings for Water Supply
F.     Steel Structures Painting Council (SSPC):
       SSPC SP 1 -Solvent Cleaning
       SSPC SP 5/NACE No. 1 – White Metal Blast Cleaning
       SSPC SP 6/NACE No. 3 - Commercial Blast Cleaning
       SSPC SPl0/NACE No. 2 - Near-White Blast Cleaning



A.     Pipeline Coatings

       1.     All buried metallic pipelines to receive cathodic protection shall be coated
              with a dielectric coating suitable for the site conditions.

       2.     All pipeline coatings shall be installed, handled, and inspected in
              accordance with AWWA, NACE, and SSPC standards to insure integrity
              during all phases of the work.

       3.     Polyethylene encasement (AWWA C 105) for pipelines receiving cathodic
              protection shall not be allowed.

       4.     Coated piping shall be handled in accordance with AWWA C2 14.

       5.     Fittings, valves, and special connections shall be factory coated with a
              fusion bonded epoxy coating in accordance with AWWA Cl 16 or field
              coated with a cold applied petrolatum tape or wax tape coating system in
              accordance with AWWA C217.

       6.    Insulating joints shall be coated with a cold applied petrolatum tape or
             wax tape coating system in accordance with AWWA C2 17.
B.     Galvanic Anodes

       1.     Galvanic anodes shall have a nominal weight of 30 pounds and a nominal
              packaged length of three feet. Each anode shall be cast with a steel core,
              and the core shall protrude from one end and shall be of sufficient length
              to permit attachment of a lead wire.

     2.       Each anode shall conform to the following chemical composition:
              Metal                                Percent by Weight
              Cadmium                              0.02-0.07
              Lead                                  0.006 maximum
              Iron                                 0.005 maximum
              Copper                               0.005 maximum
              Aluminum                             0.1 -0.5
              Zinc                                 Balance

     3.       Each anode shall be furnished with a lead wire attached to one end of the
              steel core, and the wire shall be of sufficient length to attach to the header
              cable as shown on the drawings. The wire shall be connected to the steel
              core by silver soldering, and the connection shall be mechanically secure
              before soldering with at least three turns of wire at the connection. The
              entire connection shall be insulated with an electrical potting compound.
              The cable attached to the anode shall be No. 12 AWG, Type TW or
              THWN solid, single conductor copper.

     4.       The anode shall be prepackaged in a permeable cloth bag filled with a
              mixture of 75 percent ground hydrated gypsum, 20 percent powdered
              bentonite, and 5 percent anhydrous sodium sulfate. Backfill shall have a
              grain size so that 100 percent is capable of passing through a l00-mesh
              screen. The mixture shall be firmly packed around the anode within the
              cloth bag by means of adequate vibration so that the zinc ingot is
              completely surrounded with a minimum one-inch of backfill material.

C.   Cables

     1.       All cables for test stations shall be Type THWN, stranded, copper, sized
              as shown on the drawings.

     2.       All cables for pipe joint bonds shall be Type HMW/PE, stranded, copper,
              AWG No. 4.

D.   Exothermic Welds

     1.       All cable connections to the pipe shall be accomplished utilizing an
              exothermic welding process such as “Caldweld” by Erico Products, Inc.,
              “T’hermoweld” by Continental Industries, Inc., or approval equal. Each
              cable shall be fitted with a copper sleeve for accomplishing the weld and
              cartridge, sleeves, and molds for each weld shall be furnished by the same
              manufacturer. All materials for welding shall be sized and in accordance
                  with recommendations in the manufacturers’ literature.

E.        Test Station

          1.      Ground level test stations shall be Brooks Type lRT, or approved equal,
                  traffic box with a cast iron lid. The cover shall be manufactured with “CP-
                  TEST” markings for easy identification.

F.        Test Station Panels

          1.      Test station panels shall be l/4-inch thick Micarta or Phenolic board sized
                  to fit into the test station. The test station panel shall be provided with
                  sufficient terminals for each cable and shall use Type 316 stainless steel

G.        Cable Warning Tape

          1.      All buried test station and anode cables shall have plastic warning tape
                  installed a minimum of 12 inches above the top of the cables for the entire
                  buried length of the cables. The warning tape shall be four inches wide
                  and shall be yellow with black lettering with the legend “CAUTION,
                  CATHODIC PROTECTION CABLES BURIED BELOW’ in three inch
                  high lettering printed at a minimum of seven foot intervals along the entire
                  buried length of the cable.

H.        Cable Identification Tags

          1.      All cables in the test stations shall be identified as shown on the drawings.
                  The identification tags shall be white plastic “zip-tie” type straps with a
                  plastic tab of sufficient size to allow the cable designation to be written on
                  the tab with a permanent felt tip marker.

I.        Weld Attachment Coating
          1.    Thermite welds are to be coated with a prefabricated one piece, mastic
                containing, plastic cap. Caps shall be as manufactured by Royston Model
                Handy-Cap or approved equal. The appropriate primer as required by the
                mastic cap manufacturer shall be used. Primer shall be as manufactured by
                Royston Model Roybond 747 Primer, or approved equal.

J.        Anode Current Monitoring Shunts

          1.      Anode current monitoring shunts shall be 0.01 -ohm, 6-amp capacity, with
                  1 percent accuracy.

     K.        Insulating Flanged Joints
       1.     Each insulating flange set shall consist of a full-face gasket, a full length
              sleeve for each flange bolt and two insulating washers with two steel
              washers for each bolt. The ring type central gasket shall be l/8-inch thick
              sheet packing having a high dielectric constant. Bolt sleeves shall be fabric
              reinforced phenolic resin or mylar and insulating washers shall be
              constructed of fabric reinforced phenolic resin. The complete assembly
              shall have an ANSI pressure rating equal to that of the flanges between
              which it is installed.

L.     Dielectric Unions

       1.     ASME/ANSI B 16.39, for dimensional, strength, and pressure
              requirements. Insulation barrier shall limit galvanic current to one percent
              of the short-circuit current in a corresponding metallic joint. The
              insulating material shall be impervious to water, oil, and gas.

M.     Buried Insulating Flanged Joint Coating Material

       1.     Coatings for buried insulating flanges and insulating couplings shall
              consist of a four part, non-conductive, petrolatum-based coating system.
              The four part coating system shall consist of a prime coat as an initial
              surface preparation to displace moisture on the surface. A fill material
              shall be used as required to provide a smooth contour on the surface of the
              joint. A wrap material shall be used for protection of the substrate. A
              guard material shall be used as a final coating to provide increased
              mechanical strength of the coating.

       2.     The prime coat shall be a petrolatum material with corrosion inhibitors
              and inert fillers. The material shall be free of acids, alkalies, waxes, and
              resins. The fill coat shall be a Petrolatum material with inert fillers and
              reinforcing fibers. The wrap coat shall be a non-woven, stitch bonded
              synthetic fabric saturated with a petrolatum material blended with inert
              fillers and corrosion inhibitors. The guard coat shall be plasticized, self-
              adhesive PVC tape. The coating material shall be the STAC system as
              manufactured by Central Plastics or approved equal.

N.     Reference Electrode

              Shall be manufactured as shown on the drawings using a 6-inch #4
              deformed reinforcing steel with an AWG #12, THWN insulation, test lead
              exothermically welded to the rebar. The weld attachment shall be coated
              as shown on the drawings with a mastic/heat shrink sleeve.


A.   Storage Of Materials

     All materials and equipment to be used in construction shall be stored in such a
     manner as to be protected from detrimental effects from the elements. If
     warehouse storage cannot be provided, materials and equipment shall be stacked
     well above ground level and protected from the elements with plastic sheeting or
     as appropriate.

B.   Galvanic Anodes
     Galvanic anodes shall be installed in the trench either vertically or horizontally as
     shown in the drawings after excavation to proper depth, a minimum of 5-feet from
     the pipeline. Prior to placing anodes in the trench, paper or plastic bags shall be
     removed, but the cloth bag shall remain on the anode. Care shall be exercised
     during installation to prevent damage to the cloth bag and loss of backfill
     material. After placing anodes in the trench, native soil, free of rocks and other
     foreign objects shall be placed around the anode to a minimum cover of one foot
     above the anode. Backfill shall then be flooded with water. The remainder of the
     trench shall then be backfilled with native soil. During installation, anodes shall
     not be supported or handled by use of attached wires, Backfill and compaction
     shall match the existing conditions and shall be approved by METRO.

C.   Cables

     Cables buried in the ground shall be direct buried and shall be laid straight,
     without kinks. The cable shall have a minimum cover of 30-inches. Each cable
     run shall be continuous in length and free of joints or splices. Care shall be
     exercised during installation to avoid punctures, cuts, and similar damage to
     insulation. Any damage to insulation will require replacement of the entire cable
     length. Pull boxes and splice boxes shall be installed where shown and where
     otherwise required to facilitate installation of conductors and to comply with code
     requirements. Backfill surrounding the cables shall be native soil free of foreign

D.   Cable-To-Pipe Connections (Ductile Iron And Steel Pipe)

     Cable-to-pipe connections shall be installed in the manner and at the locations
     shown on the drawings. Coating materials shall be removed from the surface over
     an area just sufficient to make the connections. The surface shall be cleaned to
     white metal by grinding or filing prior to welding the conductor. Grinding with
     resin impregnated wheels shall not be allowed. The conductor shall be welded to
     the pipe by the exothermic process with a copper sleeve fitted over the conductor,
     and only sufficient insulation shall be removed from the conductor to allow
     placing in welding mold. After the weld has cooled, all slag shall be removed and
     the weld shall be tested with a sharp hammer blow to assure proper metallurgical
     bond. All defective welds shall be removed and replaced. All exposed surfaces of
     copper and steel shall be covered with insulating materials as shown on the

E.   Test Stations

     Test stations shall be installed as shown on the drawings. Exact locations of test
     station shall be determined by the CONTRACTOR in the field and approved by
     METRO. The terminal end of each cable shall be identified with permanent cable
     markers indicating diameter and type of pipe.

F.   Joint Bonding

     All non-weld rubber gasket joints and mechanical joints shall be installed with
     two NO. 4-AWG Bond cables. The overall length of the conductor shall permit
     maximum movement of the pipe joint without transferring any tensile stress to the

G.   Insulating Flange Joints

     All insulating components of the insulating flanged gasket set shall be cleaned of
     all dirt, grease, oil, and other foreign materials immediately prior to assembly.
     Bolt holes in mating flanges shall be properly aligned at the time bolts and
     insulating sleeves are inserted to prevent damage to the insulation. After flanged
     bolts have been tightened, each insulating washer shall be inspected for cracks or
     other damage. All damaged washers shall be replaced. After assembly, resistance
     between each bolt and flange shall be measured with an approved ohmmeter and
     the minimum resistance shall be 50,000 ohms. Where the insulating joint is
     assembled in the shop and shipped as a unit, resistance shall be measured in the
     shop between the flanges and between each bolt and flange and shall meet the
     above requirements. All below grade insulating joints shall be coated as specified

H.   Coating Insulating Flanged Joints

     Surfaces shall be cleaned of all dirt, grease, oil, and other foreign materials
     immediately prior to coating. Remove loose rust, paint, and other foreign matter
     in accordance with SSPC SP2 or SP3. A prime coating shall be applied in a
     uniform coating over the entire surface to be wrapped. A liberal coating shall be
     applied to threads, cavities, shoulders, pits, and other irregularities. A fill coating
     shall be molded and packed onto irregular surfaces such as flanges, valves, or
     flexible couplings to create a smooth profile prior to wrapping. A wrap coating
     shall be spirally wrapped using a minimum of 55 percent overlap to ensure a
     double thickness of material. At the completion of each roll the overlaps shall be
     smoothed by hand in the direction of the spiral to ensure sealing of the overlap. A
     2-inch overlap shall be maintained when overlapping one roll with one end of a
       new roll. Overlap shall occur on the top half of the pipeline. A guard coating shall
       be spirally over-wrapped using a 55 percent overlap to ensure a double coating.

I.     Dielectric Unions

       Cut pipe ends square, remove all fins and burrs, and cut taper pipe threads in
       accordance with ANSI B2.1. Apply joint compound or thread tape to male threads
       only. Work piping into place without springing or forcing. Backing off to permit
       alignment of threaded joints will not be permitted. Engage threads so that no more
       than three threads remain exposed.

J.     Reference Electrode

       Reference electrodes shall be installed as shown on the drawings in the pipeline
       backfill material within 1 -foot of the pipeline.

K.     Adjacent Utilities

       Test stations and test connections to adjacent utilities shall be made in accordance
       with the standards and directives of the operating utility. Connection of test leads
       to mortar coated steel pipe shall only be made at the bell end of the pipeline. All
       coatings removed for test lead attachment shall be restored to the existing coating
       condition and approved by the operating utility.


       After installation of the cathodic protection facilities, the system shall be
       energized, tested, and adjusted by a qualified Corrosion Engineer to assure
       conformance with the specifications. Testing shall include a determination of
       proper operation of each anode bed, adequacy of test stations and insulating
       joints, electrical continuity of bonded pipe and fittings, and adequate cathodic
       protection potentials in accordance with NACE Standard RP0169-92. Upon
       completion of the tests, a detailed written report shall be submitted describing any
       deficiencies detected. Any and all deficiencies shall be corrected by the
       CONTRACTOR at his cost and retested prior to final acceptance. All retesting
       shall be at the CONTRACTOR’s expense.

                               END OF SECTION 02735

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