Cathodic Protection Joint Bonding

Cathodic Protection Joint Bonding
WATER AGENCIES’ STANDARDS
STANDARD SPECIFICATIONS
SECTION 13110
PART 1
1.01
CATHODIC PROTECTION AND JOINT BONDING
GENERAL
DESCRIPTION
This section includes materials, testing and installation of corrosion protection and monitoring
systems for metallic pipes including insulating flange kits, test stations, copper/copper sulfate
reference electrodes, sacrificial anodes, wiring, and exothermic welds.
1.02
REFERENCE STANDARDS
The publications listed below form part of this specification to the extent referenced and are referred
to in the text by the basic designation only. Reference shall be made to the latest edition of said
standards unless otherwise called for.
AWWA C217
-
ASTM D 1248 NACE RPO286 NACE RPO375 -
1.03
Petrolatum and Petroleum Wax Tape Coatings for the Exterior of
Connections and Fittings for Steel Water Pipelines
Standard Specification for Polyethylene Plastics Molding and Extrusion
Materials for Wire and Cable
The Electrical Isolation of Cathodically Protected Pipelines
Application and Handling of Wax-Type Protective Coatings and Wrapper
Systems for Underground Pipelines
RELATED WORK SPECIFIED ELSEWHERE
WAS Standard Drawings
WAS Standard Specifications 01000, 02222, 02223, 03000, 15000, 15056, 15057, and 15061.
1.04
SUBMITTALS
Submit manufacturer's catalog data on wire and cable, copper sulfate reference electrodes, test
stations, conduit, exothermic weld molds and charges, pipe flange insulation kits, pipe flange
internal coating, wax tape system, plastic warning tape, sacrificial anodes, and any other required
materials.
1.05
MANUFACTURERS
All materials furnished under this specification shall be standard products from manufacturers
regularly engaged in the manufacture of such products and shall be the manufacturer’s latest
design that complies with the specification requirements.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 1 of 9
Revised: 09/28/2009
1.06
PIPE JOINT BONDING CABLES
Electrical continuity bonding cables shall be installed across all buried or submerged metallic inline
valves, flexible couplings, grooved couplings, pipe joints that are not circumferentially welded, and
all other pipe joints except flange joints equipped with insulation gaskets. Where shown on the
drawings, bonding cables shall be installed in vaults.
1.07
GALVANIC ISOLATION
All threaded outlets shall incorporate the use of an insulated ball valve for galvanic isolation of
stray current.
Threaded outlets may incorporate the use of a nylon isolation bushing for galvanic isolation only
with the approval of the District Engineer. Where the use of nylon bushings is required, the
threaded outlet shall be increased in size to accept the bushing.
1.08
WARNING/IDENTIFICATION TAPE
All cathodic protection test wires, cables and conduit shall include Warning/Identification Tape in
accordance with Section 15000.
PART 2
2.01
MATERIALS
GENERAL
Items in this section shall be selected from the Approved Materials List in accordance with the
Standard Drawings.
2.02
TEST STATION BOXES
Cathodic test station boxes shall be circular precast concrete boxes with ductile-iron covers
selected from the Approved Materials List
2.03
PREPACKAGED COPPER SULFATE REFERENCE ELECTRODE
A.
Copper sulfate reference electrodes shall be constructed with an ion trap to prevent
contamination. The reference electrode shall have a design life of 15 years and a stability
of +/- 5 millivolts under a 3.0 microampere load.
B.
Provide reference electrodes with minimum No. 10 AWG HMW/PE (yellow) insulated wire.
Each lead wire shall be long enough to extend to the corrosion monitoring test box plus
450mm (18") of slack without splices.
C.
Reference electrodes shall be prepackaged in a permeable cotton cloth bag with low
resistivity backfill mixture to protect against the "drying out" type of failure. The backfill
mixture shall be composed of 50% Gypsum and 50% Powdered Bentonite.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 2 of 9
Revised: 09/28/2009
2.04
PREPACKAGED MAGNESIUM ANODES
Prepackaged magnesium anodes shall be used in low current demand applications. The amount
and size of magnesium anodes shall be as shown on the Approved Plans, and shall be installed in
accordance with the Standard Drawings.
2.05
A.
Prepackaged magnesium anodes shall have galvanized steel rod cores encased in
magnesium ingots. The ingot portion of anodes shall be of the weight as required on the
Approved Plans.
B.
Provide magnesium anodes with minimum No. 8 AWG HMW/PE (black) insulated wire.
Each lead wire shall be long enough to extend to the corrosion monitoring test box plus
450mm (18") of slack without splices.
C.
Magnesium anodes shall be prepackaged in a permeable cloth bag with low resistivity
backfill mixture and shall be selected from the Approved Materials List.
SACRIFICIAL ANODES FOR COPPER TUBING
Prepackaged zinc sacrificial anodes shall be installed and connected to copper tubing where
indicated on the Approved Plans. Anodes shall be selected from the Approved Materials List and
shall be installed in accordance with the Standard Drawings.
2.06
A.
Prepackaged zinc sacrificial anodes shall include a zinc-alloy ingot with galvanized steel
core weighing not less than 6.8 kg (15 lbs.) and shall be packed in cloth bags filled with a
mixture of gypsum and bentonite.
B.
Prepackaged zinc sacrificial anodes shall include an integral anode lead connected to the
galvanized steel core of the ingot consisting of No. 12 AWG stranded copper wire with
(black) THW insulation. Anode lead wires shall be a minimum of 7.62 m (25’) long.
TEST CABLE AND BONDING CABLE
All test cable and bonding cable shall be stranded copper wire with insulation rated at 600 volts.
Cable with cut or damaged insulation is not acceptable. All cable shall be of sufficient length to
extend from the point of connection to the appropriate corrosion monitoring test box without splices.
The cable shall have a 2.8mm (7/64") thick, high molecular weight polyethylene (HMW/PE)
insulation specifically designed for cathodic protection service and suitable for direct burial in
corrosive soil or water, conforming to ASTM D 1248, Type I, Class C, Category 5 (HMW/PE Type
CP) Grade E-5 or J-1. Test cable shall have at least 450mm (18") of slack in the test box. Cable
size shall be in accordance with the Standard Drawings.
2.07
PIPE FLANGE INSULATING KITS
All pipe flange-insulating materials shall be of the type designated by the manufacturer as suitable
for service at the operating temperatures and pressures of the pipeline.
A.
Insulating gaskets shall be full-face dielectric neoprene-faced phenolic.
B.
Insulating sleeves shall be full-length phenolic
C.
Insulating washers shall be phenolic.
D.
Steel bolts, nuts, and washers shall be in accordance with Section 15000.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 3 of 9
Revised: 09/28/2009
2.08
ADDITIONAL SMOOTH EPOXY LINING AT INSULATED PIPE FLANGES
In addition to the cement mortar lining, the interior of the pipe at all insulated flanges shall be coated
with a two-part smooth white liquid epoxy consisting of 100 percent solids.
2.09
TAPE WRAP FOR ABOVEGROUND INSULATED PIPE FLANGES
All aboveground insulated pipe flanges shall be wrapped with minimum 0.36mm (14 mil) thick
general utility pipeline tape in accordance with the Approved Materials List.
2.10
WAX TAPE COATING FOR BURIED INSULATED PIPE FLANGES
All buried insulated pipe flanges shall be coated with a three-part, cold-applied wax tape coating
system as described by NACE RPO375 and AWWA C217 in accordance with the Approved
Materials List. Wax tape is also required where indicated on the Approved Plans.
A.
Primer: Primer shall be a blend of petrolatums, plasticizers and corrosion inhibitors having
a paste-like consistency. The primer shall have the following properties:
Color
Pour Point
Flash Point
Coverage
B.
Wax Tape: Wax tape shall consist of a plastic-fiber felt, saturated with a blend of
petrolatums, plasticizers, and corrosion inhibitors, forming a tape coating that is easily formable over irregular surfaces. The tape shall have the following properties:
Color
Saturant Pour Point
Thickness
Tape Width
Dielectric Strength
C.
Brown
46.1º C - 48.9º C (115º - 120º F)
1.27 - 1.78 mm (50 - 70 mils)
150mm (6")
170 volts/mil
Tape Outerwrap: Wrapper shall be a polyvinylidene chloride plastic with three 50-gauge
plies wound together as a single sheet. The wrapper shall have the following properties:
Color
Thickness
Dielectric Strength
Tape Width
Water Absorption
2.11
Brown
37.8º C - 43.3º C (100º -110º F)
176.7º C (350º F)
0.41 L/M2 (1 gal/100 sq. ft.)
Clear
0.0381 mm (1.5 mils)
2000 volts/mil
150mm (6")
Negligible
EXOTHERMIC WELD MOLDS AND WELD CHARGES
Wire-to-pipe connections shall be made using exothermic welds. Weld charges and mold sizes for
various surface configurations and materials shall be in accordance with the manufacturer’s
recommendations.
2.12
REPAIR GROUT FOR EXOTHERMIC WELDS
Repair grout shall be in accordance with cement-mortar grout described in Section 15061.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 4 of 9
Revised: 09/28/2009
2.13
BRASS IDENTIFICATION TAGS
All wires terminating in CP Test Boxes shall be identified with brass tags securely attached to the
wires with nylon fasteners. The tags shall be 38mm (1½") in diameter, 1.6mm (1/16”) thick, and
shall be die-stamped with identifying letters and numbers 6.4mm (¼”) high.
2.14
WARNING/IDENTIFICATION TAPE
Warning/Identification tape materials shall be in accordance with Section 15000 and the Approved
Materials List.
2.15
CONCRETE
Concrete shall be in accordance with Section 03000.
PART 3
3.01
EXECUTION
CORROSION MONITORING TEST STATIONS
All test stations shall be installed behind existing or proposed curbs or otherwise out of traffic lanes
to allow safe access for personnel during testing in accordance with the Standard Drawings. A
utility marker post shall be installed, in accordance with the Standard Drawings, when indicated on
the Approved Plans.
3.02
EXOTHERMIC WELDS
All cable-to-pipe connections shall be made using exothermic welds in accordance with the
Standard Drawings.
A.
Preparation of Cable: Cut cable with a wire cutter to prevent deforming the cable ends.
Remove only enough insulation from the cable to allow the weld connection to be made.
B.
Preparation of Pipe: The surface of the steel or ductile-iron pipe shall be ground or filed to a
bright, shiny, clean and dry surface before welding the cable connection. For cementmortar coated pipe, a nominal 75mm x 75mm (3" x 3") area of cement mortar shall be
chipped off.
C.
Attachment of Cable to Structure: The attachment of the cable to the structure shall be
made using an exothermic weld. The cable shall be held at a 30º to 45º angle to the
surface when welding. Only one cable shall be attached with each weld. All cable-to-pipe
welds shall be a minimum of 75mm (3”) apart. All weld slag shall be removed from the
weldment with a wire brush.
D.
Weldment Test: After the exothermic weld has cooled, the weld shall be tested by the
Contractor for strength, in the presence of the District Engineer, by striking the weldment a
sharp blow with a 0.91 Kg (2 lb.) hammer while pulling firmly on the cable. All unsound
welds shall be re-welded and retested.
E.
Repair Grout: The area to be repaired shall be thoroughly clean and dry. Cement-mortar
coating shall be repaired or replaced to original condition by hand-placing cement-mortar
repair grout as directed by the District Engineer.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 5 of 9
Revised: 09/28/2009
3.03
PIPE FLANGE INSULATING KITS
Pipe flange insulating kits shall be installed at the locations shown on the Approved Plans and in
accordance with the Standard Drawings and the manufacturer's recommendations. Insulation shall
also conform to the National Association of Corrosion Engineers’ Recommended Practice RPO286
"Electrical Isolation of Cathodically Protected Pipelines". Particular attention shall be paid to
properly align the pipe flanges prior to inserting the bolts with insulating sleeves to prevent cutting of
the sleeves and creating an electrical path when the bolts are tightened. Care shall be taken to
prevent any moisture, soil, or other foreign matter from contacting any portion of the two mating
pipe flanges or gaskets prior to or during installation. If any foreign matter contacts any portion of
the insulated pipe flange, the entire pipe joint shall be disassembled, cleaned with a suitable solvent
and dried prior to reassembly. Strictly follow the manufacturer's recommendations regarding the
torque pattern of the bolts and the amount of torque to be used when installing the pipe flange
insulating kit. Conductive grease shall not be used on the flange bolts or any other flange
components under any circumstances. Refer to Field Testing below for testing of the flange
insulation kits.
3.04
ADDITIONAL SMOOTH EPOXY LINING AT INSULATED PIPE FLANGES
At all insulated pipe flanges, an additional two-part smooth epoxy lining shall be applied. The
interior of the pipe and flanges shall be coated with the two-part smooth epoxy for a distance of two
pipe diameters in each direction away from the insulated pipe flange.
3.05
A.
Surface Preparation: The surface preparation shall consist of wire brushing to remove all
rust and scale and to provide a suitable surface for adhesion of the coating in accordance
with the manufacturer’s recommendations.
B.
Mixing the Coating: The two-part epoxy paint shall be mixed per the manufacturer's
recommendations. The two-part epoxy shall be mixed thoroughly for at least two minutes
by hand or with a mechanical mixer before being applied by brush.
C.
Applying The Coating: The application of the undiluted coating shall be made by brushing
until a minimum dry film thickness (DFT) of 0.51mm (20 mil) is achieved. Each subsequent
coat shall be applied before the preceding coat cures, which is normally within 3-6 hours.
The application of the coating shall be per the guidelines and at the rate recommended by
the coating manufacturer.
WAX-TAPE COATING FOR BURIED INSULATED PIPE FLANGES
After continuity testing, all flange and pipe surfaces shall be clean and free of all dirt, grease, water
or other foreign material prior to the application of the primer, wax tape, and tape outerwrap.
A.
Apply primer by hand or brush to all surfaces of the flanges. Work the primer into all
crevices, around bolts and nuts, and completely cover all exposed metal surfaces. Extend
the primer a minimum of 75mm (3") onto adjacent surfaces of the pipe or valve.
B.
Apply the wax tape immediately after the primer application. Cut short lengths of tape and
place completely around each bolt head and nut. Work the tape into the crevices around
the bolts and nuts. Wrap the wax tape spirally around the pipe and across the flanges to
the other pipe or valve. Cover the entire primed area with wax tape using a minimum
overlap of 55% of the tape width. Work the tape into the crevices and contours of the
irregular shaped surfaces and smooth out so that there is a continuous protective layer with
no voids or spaces under the tape.
C.
Apply the tape outerwrap to the completed wax tape installation. Wrap spirally around the
pipe and across the flanges. Extend the plastic wrap 75mm (3") past the wax tape using a
minimum overlap of 55% of the plastic material width to apply two layers of overwrap.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 6 of 9
Revised: 09/28/2009
3.06
PREPACKAGED MAGNESIUM ANODES
Prepackaged magnesium anodes shall be placed a minimum of 1.5m (5’) below the pipe in the
trench or an augured hole. Soaking of the anode is not required. Backfill material around the
prepackaged anodes shall be as specified for the pipeline trench. Installation shall be in
accordance with the Standard Drawings.
3.07
SACRIFICIAL ANODES FOR COPPER TUBING
Prepackaged zinc sacrificial anodes shall be installed in accordance with the Standard Drawings.
A.
Anode Location:
1.
Anodes to be attached to new copper tubing installed by trenching shall be
installed horizontally, and shall be located within the paved roadway approximately
1.52m (5’) to 3.05m (10’) from the edge of the roadway. New copper tubing trench
shall be over-excavated at anode location to a depth necessary to provide 600mm
(24”) minimum vertical separation between new copper tubing and anode.
2.
Anodes to be attached to existing copper tubing or to new copper tubing to be
installed by boring shall be installed vertically in a 1.22m (4’) deep, 200mm (8”)
minimum diameter augured hole located adjacent to the meter box.
3.
Anodes to be attached to existing copper tubing in conjunction with the
replacement of existing pipelines shall be installed horizontally, and shall be
located within the new water main trench below the new water main. New water
main trench shall be over-excavated directly below locations where new water
main is to be connected to existing copper tubing to a depth necessary to provide
600mm (24”) minimum vertical separation between copper tubing and anode.
B.
Anodes shall be hand-placed into over-excavated trenches or augured holes. Anodes shall
be handled with care and shall not be carried, suspended or dropped by holding the
attached lead wire.
C.
Anode Attachment:
1.
Anodes to be installed within new copper tubing trenches or within augured holes
as described above and intended for the protection of service laterals shall be
attached to copper tubing within meter boxes. Anode lead wire shall be securely
attached to the copper tubing between anode and meter box, 600mm (24”) of
excess wire shall be coiled above ground within the meter box and remaining wire
shall be cut. 50mm (2”) of insulation shall be removed from end of anode lead wire
and bare wire shall be clamped to the vertical portion of the copper tubing lying
immediately below the angle meter stop. Clamp shall be entirely brass or copper,
selected from the Approved Materials List. Connection point must be waterproof
and shall be securely wrapped with dielectric tape selected from the Approved
Materials List.
2.
Anodes to be installed within new copper tubing trenches or within augured holes
as described above and intended for the protection of copper tubing for air valves
shall be attached to copper tubing within air valve enclosures. Anode lead wire
shall be installed through concrete air valve slab within 25mm (1”) PVC sleeve, and
600mm (24”) of excess wire shall be coiled and placed within the sleeve. 50mm
(2”) of insulation shall be removed from end of anode lead wire and bare wire shall
be clamped to copper tubing 75mm (3”) above concrete slab. Clamp shall be
entirely brass or copper, selected from the Approved Materials List. Connection
point must be waterproof and shall be securely wrapped with dielectric tape
selected from the Approved Materials List.
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 7 of 9
Revised: 09/28/2009
3.
D.
3.08
Anodes to be installed within new water main trenches as described above and
intended for the protection of existing copper tubing shall be clamped to copper
tubing at a point approximately 25mm (3”) from the corporation stop. Connection
point shall be backfilled along with the new water main, and no excess wire is
required. Clamp shall be entirely brass or copper, selected from the Approved
Materials List. Connection point must be waterproof and shall be securely
wrapped with dielectric tape selected from the Approved Materials List.
Over-excavated trenches or augured holes in which anodes are placed shall be backfilled
with select native material from which rock or other materials larger than 25mm (1”) in
diameter have been removed. Over-excavated trenches shall be backfilled with native
materials up to the bottom of the new water main or copper tubing trench, which shall then
be backfilled with select material in accordance with these Standard Specifications. Anode
and native backfill shall be thoroughly wetted after installation.
COPPER SULFATE REFERENCE ELECTRODES
Reference electrodes shall be placed 300mm (12”) away from the pipe at spring line. Electrodes
shall be placed opposite side of the pipe from anodes. Saturate packaged electrode in 18.9 liters (5
gallons) of water prior to installation. Backfill material around the electrode shall be as specified for
the pipeline trench. Installation shall be in accordance with the Standard Drawings.
3.09
TEST CABLE
All buried test cable requiring trenching to the test station box location shall be installed, without
splices, in a conduit in the trench at a minimum depth of 600mm (24"). Trenches shall be
compacted in accordance with Section 02223. Care shall be taken when installing wire and
backfilling trench to prevent damage to the installation. Damaged wire shall be replaced in entirety.
3.10
WARNING/IDENTIFICATION TAPE
Warning/Identification Tape shall be installed in accordance with Section 15000 and the Standard
Drawings
3.11
BRASS IDENTIFICATION TAG
Brass identification tags shall be used to identify all cables in all test boxes. Care shall be taken to
accurately maintain the wire identities. The tags for all test cables shall be stamped with the District
or Agency name, the pipeline size, the contents of the pipeline, and the direction of the connection
point along the pipe, in accordance with the Standard Drawings. Copper sulfate reference
electrode tags at cathodic test boxes shall be stamped "CuSO4". The tags shall be securely
attached to each wire with nylon fasteners prior to pipe backfilling operations.
3.12
FIELD TESTING
The Contractor shall test the cathodic protection installations in the presence of the District
Engineer. Contractor shall notify District Engineer of proposed test dates and times a minimum of
48 hours in advance. As a practical approach, the Contractor may choose to verify pipe continuity
and flange isolation (described in Items A and B below) prior to backfilling as an unofficial test.
Official testing shall occur after the backfilling and installation of the test boxes..
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 8 of 9
Revised: 09/28/2009
3.13
A.
Pipeline Electrical Continuity Testing: Test the electrical continuity of all sections of pipe to
be monitored between each pair of adjacent corrosion monitoring test stations or between
the ends of pipe sections less than 152.4m (500') apart. Each pipe section shall be
considered electrically continuous when the measured longitudinal resistance of each pipe
section is no greater than 20% higher than the theoretical resistance of that section of pipe.
If testing indicates inadequate electrical continuity, the Contractor shall excavate to
investigate and locate improperly bonded pipe joints and make repairs until electrical
continuity is accomplished to the satisfaction of the District Engineer.
B.
Insulated Pipe Flange Testing: Each insulated pipe flange will be tested for effective
electrical isolation of the two mating pipe flanges. The insulated pipe flange shall be judged
for effectiveness in accordance with NACE RPO286, Section 7, Field Testing and
Maintenance." The Contractor shall replace or repair any insulated pipe flange assembly
until electrical discontinuity is accomplished.
D.
Initial Reference CP Potential Measurements: The entire metallic piping system shall be
tested to establish the base CP Potential measurement readings. The base data will be
used for comparative purposes with future monitoring data. The baseline data shall include
voltage measurements (+/- 1mV) between any permanent copper sulfate reference
electrodes (+ voltmeter correction) and a reliable portable copper sulfate reference
electrode (- voltmeter correction) placed directly in the CP test box.
E.
Sacrificial Anode Connectivity Testing: After installation of sacrificial anodes for copper
tubing, the copper tubing and sacrificial anode lead wire shall be tested for connectivity to
insure that the lead wire and the brass or copper clamp has been securely connected to the
copper tubing. Test method shall be as directed by the District Engineer.
CATHODIC TESTING REPORT
At the completion of the testing, a report of the results will be prepared and presented to the District
Engineer. The report shall be typed and shall include, at a minimum, test locations, date of tests,
name of technician, testing methods, voltage measurements, and theoretical and calculated
resistance.
END OF SECTION
Standard Specifications
Cathodic Protection and Joint Bonding
13110 - 9 of 9
Revised: 09/28/2009
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