point and the midpoint as a minimum. The locations of these
measurements shall be identical to the locations specified for
measuring energized [structure-to-electrolyte] potentials. Use
the same measuring equipment that is specified for measuring
protected potential measurements.
[For underground storage tanks, take a minimum of three
measurements with the reference electrode located as follows:
(1) Directly over the longitudinal and transverse centerlines of
the tank at intervals not exceeding the diameter of the tank and
to a distance from the tank of two times the tank diameter.
(2)
At points directly around the circumference of the tank.]
b. Permanent reference electrode calibration: Verify calibration
of the reference electrode by measuring the potential difference
between the permanent reference electrode and an independent
(portable) calibrated reference electrode placed in the soil or
water adjacent to or as close as practicable to the permanent
reference electrode. [Potential differences between the two
electrodes of the same generic type should not exceed [10] [15]
millivolts.] [Zinc permanent reference electrodes should be
within the range of -1000 to -1150 millivolts when calibrated with
a copper-copper sulfate reference electrode.] Permanent reference
electrodes not within these potential differences shall be removed
from the construction site by the end of the day and replaced at
the contractor's expense. The testing provision shall also apply
to replacement reference electrodes as well.
c.
Insulation joint testing: Perform insulation testing at each
insulating joint or fitting [prior to burying the joint or
fitting] before and after the cathodic protection system is
energized. Before energizing, test using an insulation checker.
After energizing, test the insulation by measuring the potential
shift on both sides of the insulating joint. This testing shall
demonstrate that no metallic contact or short circuit exists
between the two insulated sections of the pipe. Report and repair
defective insulating fitting at the Contractor's expense.
d.
Electrical continuity testing: Perform electrical continuity
testing for joint bonded pipe prior to backfilling of the pipe.
[Circulate current through the pipe and compare the measured
resistance to the theoretical resistance of the pipe and bond
cables. The resistance measured shall not exceed 150 percent of
the theoretical resistance.]
e.
Rectifier system testing: Upon completion of the installation,
"Baseline Potential Tests", "Insulation Joint Tests", and
"Electrical Continuity Tests", energize and adjust each rectifier.
Measure D.C. outputs of the rectifier and current outputs [of
each anode] [of associated ground bed] at different rectifier
settings. Measure the current outputs across the installed
shunts. Verify these readings using portable, calibrated meters
and shunts. This testing shall demonstrate if the rectifier
system is capable of functioning properly as required to provide
effective cathodic protection.
f.
Pipe casing testing: Before final acceptance of the installation,
test the electrical insulation of the carrier pipe from casings
SECTION 13111N
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