DaimlerChryslerConstruction Standards

12/17/04

Copyright 2002, The American Institute of Architects (AIA)

SECTION 13110 - CATHODIC PROTECTION

Verify that Section titles referenced in this Section are correct for this Project's Specifications; Section titles may have changed.

PART 1 - GENERAL

1.1SUMMARY

  1. This Section includes passive cathodic protection systems that use magnesium anodes to protect iron and steel piping and fittings.

1.2PERFORMANCE REQUIREMENTS

  1. Refer to Article 5.7 on page25 of the Geotechnical Subsurface Investigation Report.
  2. Engage a qualified corrosion engineer to design and supervise, test, and inspect installation of cathodic protection systems.
  3. Design cathodic protection for pipelines and fittings according to NACERP0169.
  4. Select anodes and accessories relevant to level of protection. Design anodes for an estimated life of 30 years before replacement.
  5. Cathodic protection systems shall provide protective potential that complies with referenced NACE standards.

1.3SUBMITTALS

  1. Product Data: For each of the following items:
  2. Anodes.
  3. Insulating flange sets.
  4. Casings, insulation, and seals.
  5. Shop Drawings: Detail location of cathodic protection equipment, devices, and outlets, with characteristics and cross-references to products. Include calculations and details of anode designs. Include plans, elevations, sections, details for attachments to other work, and list of equipment and materials.

Retain first paragraph below if special coordination is required.

  1. Coordination Drawings: Plans drawn to scale and coordinating connections to piping.
  2. Qualification Data: For corrosion engineer specified in "Quality Assurance" Article. Submit evidence of current license, corporate registration (if applicable) of the engineering business, and NACE certifications.

Retain first paragraph below if Contractor is responsible for field quality-control testing.

  1. Field quality-control test reports.
  2. Operation and Maintenance Data: For cathodic protection system to include in emergency, operation, and maintenance manuals.

1.4QUALITY ASSURANCE

  1. Corrosion Engineer Qualifications: A professional engineer who is licensed to practice in jurisdiction where Project is located and who is experienced in corrosion engineering. Qualifications shall include education and experience in cathodic protection of buried and submerged metal structures and accreditation or certification by NACE as a Corrosion Specialist or Cathodic Protection Specialist.

1.5DELIVERY, STORAGE, AND HANDLING

  1. Protect anodes from exposure to rain and direct sunlight. Replace anodes damaged due to improper handling or exposure.

PART 2 - PRODUCTS

2.1MANUFACTURERS

  1. Manufacturers: Subject to compliance with requirements, provide products by one of the following:
  2. Anodes, Cable, and Backfill:
  3. Anode Technologies Group; ELTECH Systems Corporation.
  4. Cott Manufacturing Company.
  5. CP Masters, Inc.
  6. Electro-Chemical Devices, Inc.
  7. Gerome Manufacturing Company.
  8. Harco Technologies; Corrpro Companies, Inc.
  9. Loresco International.
  10. MATCOR, Inc.
  11. Northern Arizona Wind & Sun, Inc.
  12. Wire, Cable, and Wiring Accessories:
  13. Continental Industries; thermOweld Division.
  14. ERICO International Corporation.
  15. Holloway Shunts.
  16. Rome Cable Corporation.
  17. Royston Laboratories Division; Chase Corporation.
  18. 3M; Electrical Products Division.

Retain one or more of first three articles below for applicable anode materials. Corrosion engineering survey of local conditions will indicate which anode is suitable. Additional adjustment of chemical composition may be indicated for providing adequate and economical service.

2.2MAGNESIUM ANODES, TYPEII

  1. Comply with ASTMB843.
  2. Chemical composition as percent of weight shall be as follows:
  3. Aluminum: 5.3 to 6.7.
  4. Manganese: 0.15 to 1.3.
  5. Zinc: 2.5 to 3.5.
  6. Silicon: 0.30 maximum.
  7. Copper: 0.05 maximum.
  8. Nickel: 0.003 maximum.
  9. Iron: 0.003 maximum.
  10. Other Impurities: 0.05 percent each; 0.3 percent maximum total.
  11. Magnesium: Remainder.
  12. Bare Anode Weight: 32 lb, not including core, and a minimum length of 20 inches.
  13. Anodes Core: Galvanized steel with anode wire silver-soldered to the core. Connection shall be recessed and epoxy insulated for 600-V rating. Connection shall be covered with heat-shrinkable tubing, and insulation shall be extended over connection.
  14. Anode Wires: Cables, with copper conductors, suitable for direct burial; not less than No.10AWG with TypeTHWN insulation according to ASTMD1248 and NEMAWC70; long enough to extend to accompanying junction box without splicing.
  15. Anode Backfill: Backfill materials packaged in water-permeable fabric sack or cardboard container. Anodes shall be factory installed in packaged backfill using methods that result in dense packing of fill with factory-installed anode spacers to ensure centering of anode in packaged anode backfill. Backfill material shall have the following chemical composition by weight:
  16. Hydrated Gypsum: 75 percent.
  17. Bentonite Clay: 20 percent.
  18. Anhydrous Sodium Sulfate: 5 percent.

2.3WIRE AND CABLE

  1. Direct-Burial Cable: Single-conductor TypeHMWPE, insulated cable specifically designed for dc service in cathodic protection installations.
  2. Conductor: Stranded, annealed, uncoated copper, complying with ASTMB3 and ASTMB8.
  3. Insulation: High-molecular-weight polyethylene, complying with NEMAWC70.
  4. Minimum Average Thickness of Insulation: 110 mils for Nos.8 through 2AWG, and 125 mils for Nos.1 through 4/0AWG; rated at 600V.
  5. Connectors: Copper compression type or exothermic welds.
  6. Cables for Installation in Conduit: TypeTHWN copper conductors as specified in Division16 Section "Conductors and Cables."

2.4TEST AND JUNCTION BOXES

  1. Test Stations: Flush-mounting type of high-impact-resistant PVC or polycarbonate, with watertight conduit connections and cover and removable terminal board.

For traffic box below, verify that AASHTO's "Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals," H20 traffic loads, is adequate, or delete paragraph if no boxes are in traffic areas.

  1. In-Ground Level Test Stations: Traffic box with cast-iron covers, capable of withstanding AASHTO's "Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals," H20 traffic loads, and with welded bead legend "CP TEST."

2.5PATCH, SEAL, AND REPAIR COATING

  1. Sealing and Dielectric Insulating Compound: Black, rubber based, soft, permanently pliable, tacky, moldable, and unbacked; 0.125 inch thick.
  2. Coating Compound: Cold-applied, coal-tar-based mastic.
  3. Pressure-Sensitive, Vinyl-Plastic Electrical Tape: Comply with UL510.

2.6POTTING COMPOUND

  1. Cast-epoxy, two-package type; fabricated for this purpose and covered with heat-shrinkable tape.

2.7IDENTIFICATION MATERIALS

  1. Materials are specified in Division16 Section "Electrical Identification."
  2. Wire and Cables: Laminated-plastic material with black letters on yellow background. Include identifier legend on Shop Drawings.
  3. Cable Warning Tape: Polyethylene tape, complying with requirements in Division16 Section "Electrical Identification."

2.8INSULATING FLANGE SETS

Coordinate requirement for flanges and unions with piping and storage tank Sections in Divisions2 and 15.

  1. Description: Insulating flange sets rated for operation at indicated pressure and temperature of piping system, with full-faced gaskets, insulating sleeves and washers, and steel washers.
  2. Gaskets: ASMEB16.21. Laminated phenolic material.
  3. Insulating Washers and Sleeves: Two sets of laminated phenolic insulating material. Select washers to fit within bolt facing on flange over the outside of fabric-reinforced phenolic sleeve.
  4. Washers: Steel, cadmium plated, to fit within bolt facing on flange.

2.9STEEL FLANGES AND BOLTS

  1. Steel Flanges: ASMEB16.5; 150 lb, unless otherwise requirements of piping system being protected.
  2. Bolts: ASTMA307, GradeB for bolts; ASTMA194/A194M, Grade2 for nuts.
  3. Dimensions: ASMEB18.2.1 for bolts; ASMEB18.2.2 for nuts.
  4. Threads: ASMEB1.1; Class2A fit for bolts, Class2B fit for nuts.
  5. Extend bolts completely through nuts.
  6. Bolts may have reduced shanks of diameter not less than diameter at roof of threads.

2.10FLEXIBLE PIPE COUPLING BONDS

  1. Description: Flexible copper straps with electrical resistance equal to No.1/0AWG stranded copper wire and with 5 holes for 5 exothermic welds to pipe.

2.11EXOTHERMIC WELDS

  1. Exothermic Weld Kits: Specifically designed by manufacturer for welding materials and shapes required.
  2. Exothermic Weld Caps: Dome of high-density polyethylene, 10-mil minimum thickness, filled with mastic and containing a tunnel portion to separate lead wire from exothermic weld.

PART 3 - EXECUTION

3.1GENERAL INSTALLATION REQUIREMENTS

  1. Comply with ANSIC2 and NFPA70.
  2. Make connections to ferrous pipe and/or fittings using exothermic welding.
  3. Coat welds with primer and exothermic weld cap.

3.2MAGNESIUM ANODE INSTALLATION

  1. Install magnesium anodes at locations that clear obstructions. Install minimum 36 inches and maximum 10 feet from line to be protected. Install in augered holes with top of anode 24 inches below pipe invert. In soils that will collapse augered holes, use casing of galvanized sheet metal.
  2. Install anodes in a dry condition after plastic or waterproof protective covering has been completely removed from water-permeable, permanent container housing the anode metal. Do not use anode connecting wire for lowering anode into hole. Backfill annular space around anode with fine earth in 6-inch layers; compact each layer using hand tools. Do not strike anode or connecting wire during compacting. After backfilling and compacting to within 6 inches of finished grade, pour approximately 5 gal. of water into each filled hole. After water has been absorbed by earth, complete backfilling to finished level.
  3. Cover trench bottom for the anode wire with 3-inch layer of sand or stone-free earth. Center wire one backfill layer and do not stretch or kink the conductor. Place backfill over wire in layers not exceeding 6 inches in depth, and compact each layer. Use clean fill, free from tree roots, wood scraps, vegetable matter, and refuse. Place cable warning tape within 18 inches of finished grade, above cable and conduit.
  4. If rock strata is encountered before achieving specified augured hole depth, install anodes horizontally at depth at least as deep as bottom of pipe to be protected.
  5. Install anodes spaced as required, connected through a test station to the pipeline, allowing adequate slack in connecting wire to compensate for movement during backfill operation.
  6. Do not use resistance wires to reduce current output of individual or group anodes.

3.3CABLE AND WIRE INSTALLATION

  1. Install conductors in PVC conduit with waterproof PVC junction boxes according to Division16 Section "Raceways and Boxes."
  2. Minimum Conductor Size: No.10AWG.
  3. Install direct-buried cables according to Division16 Section "Conductors and Cables."
  4. Minimum Conductor Size: No.8AWG.

3.4TEST STATIONS

  1. Install test stations as follows:
  2. At 1000-foot intervals.
  3. At insulating joints.
  4. At both ends of casings.
  5. Where pipe crosses other metal pipes.
  6. Where pipe connects to existing piping system.
  7. Where pipe connects to dissimilar metal pipe.
  8. Install test stations on controlled backfill complying with requirements for trench bottom fill for anode wires, unless otherwise indicated.
  9. Terminate test conductors on terminal boards and install a spare set of test leads at each testing location.

3.5INSULATING FLANGE SETS

  1. Cut piping and install flanges without stressing piping. Weld flanges according to ASMEB16.25. Cover flanges with sealing and dielectric compound.

3.6PIPE JOINTS

  1. Electrical Continuity: Install bonding straps on metallic pipe to and across buried flexible couplings, mechanical joints, and flanged joints, except at places where insulating joints are specified. Welded and threaded joints are considered electrically continuous. Size bonding strap to allow for a total of 1-inch pipe expansion or contraction. Connect bonding strap to pipe, coupling follower rings, and coupling middle ring or sleeve. Connect bonding strap to pipe and coupling with five thermowelds.
  2. Insulating Unions: Install electrical isolation at each building entrance and at other locations indicated. Cut pipe ends square, remove fins and burrs, and cut tapered pipe threads according to ASMEB1.20.1. Apply joint compound or thread tape to male threads only. Install piping without stressing pipe. If joints are backed off to permit alignment of threaded joints, reapply joint compound or tape. Engage threads so not more than three threads remain exposed. Cover unions with sealing and dielectric compound.

3.7DISSIMILAR METALS

  1. Underground Dissimilar Piping: Install electrically isolated joints for new and existing steel piping, except valves. Coat insulating joint and pipe with sealing and dielectric compound for a minimum distance of 10 pipe diameters on both sides of joint.
  2. Underground Dissimilar Valves: Coat dissimilar ferrous valves and pipe with sealing and dielectric compound for a minimum distance of 10 pipe diameters on both sides of valve.
  3. Aboveground Dissimilar Pipe and Valves: If dissimilar metal pipe joints and valves are not buried and are exposed only to atmosphere, coat connection or valve, including pipe, with sealing and dielectric compound for a minimum distance of three pipe diameters on both sides of junction.

3.8CASINGS, INSULATION, AND SEALS

Retain this Article if protected piping is installed in conduits or casings.

  1. If piping is installed in casing, insulate piping from casing and seal annular space to prevent intrusion of water.

3.9IDENTIFICATION

  1. Identify test station as indicated on Shop Drawings.

3.10FIELD QUALITY CONTROL

  1. Testing Agency: Construction Manager will engage a qualified testing and inspecting agency to perform field tests and inspections and prepare test reports.
  2. Static Pull Test: Choose, at random, one completed anode of each type for this destructive test. Demonstrate that anode wire connections have enough strength to withstand a minimum tensile load of 300 lb. If test fails, replace all anodes and repeat test at another randomly selected anode.
  3. Insulation Testing: Before anode system is connected to pipe and fittings, test insulation at each insulating joint and fitting. Demonstrate that no metallic contact, or short circuit, exists between the two insulated sections of pipe and fittings. Replace defective joints or fittings.
  4. Baseline Potentials: After backfilling of pipe and fittings anodes is completed, but before anodes are connected to pipe and fittings, measure the static potential of pipe and fittings to soil. Record initial measurements.
  5. Anode Output: Measure electrical current as anodes or groups of anodes are connected to pipe and fittings. Use a low-resistance ammeter. Record current, date, time, and location of each measurement.
  6. Pipe- and- Fittings to-Reference Electrode Potential Measurements: On completion of installation of entire cathodic protection system, make electrode potential measurements according to NACERP0169, using a copper/copper-sulfate reference electrode and a potentiometer-voltmeter, or a dc voltmeter with an internal resistance (sensitivity) of not less than 100,000 ohms per volt and a full scale of 1 or 2V. Make measurements at same locations as those used for baseline potentials. Record voltage, date, time, and location of each measurement, using one of the following two methods:
  7. 850-mV Negative Voltage: With cathodic system in operation, measure a negative voltage of at least minus 0.85V between pipe and a saturated copper/copper-sulfate reference electrode contacting the earth directly over pipe.
  8. 100-mV Polarization Voltage: Determine polarization voltage shift by interrupting protective current and measuring polarization decay. An immediate voltage shift will occur if protective current is interrupted. Use voltage reading, after immediate shift, as base reading from which to measure polarization decay. Measure at least a minimum polarization voltage shift of 100 mV between pipe and a saturated copper/copper-sulfate reference electrode contacting the earth directly over pipe.
  9. Location of Measurements for Piping and Fittings: For coated piping or conduit, measure from reference electrode in contact with the earth directly over pipe. Measure at intervals not exceeding 400 feet. Make additional measurements at each distribution service riser, with reference electrode placed directly over service line.

Retain paragraph below if protected pipe is installed in conduits or casings.

  1. Casing Tests: Test insulation between carrier pipe and casing. Correct short circuits.

Retain test below if there is a possibility of adverse effects from foreign pipes and tanks.

  1. Interference Testing: Test interference with cathodic protection from any foreign pipes in cooperation with Owner of foreign pipes. Report results and recommendations.

3.11ADJUSTING

  1. Adjust cathodic current using resistors as recommended by Corrosion Engineer.
  2. During one year after Substantial Completion, test, inspect, and adjust cathodic protection system every three months to ensure its continued compliance with specified requirements.

3.12DEMONSTRATION

  1. Engage a factory-authorized service representative to train Owner's maintenance personnel to adjust, operate, and maintain cathodic protection system.

END OF SECTION

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