UFC 3-570-06
JANUARY 31 2003
Table 4-4. Corrosion Survey Potential Measurements (Continued)
STRUCTURE TYPE
POTENTIAL MEASUREMENT LOCATIONS
Take one structure-to-electrolyte (S/E) potential measurement on
ISOLATED
each side of all dielectric couplings without moving the reference
STRUCTURES
electrode.
Note: If the potential difference between measurements on each
side of a dielectric coupling is less than 10 millivolts, verify its
integrity using an isolation flange tester.
Locate the reference cell:
ALL STRUCTURES
WITH FOREIGN LINE
a)
Over the foreign line at all points where it crosses the
protected structure.
b)
Over the foreign line where it passes near by the anode
bed.
Locate the reference cell:
ALL STRUCTURES
WITH CASED
a)
Over the protected structure on each side of all casings.
b)
Over each end of the casing on all casings.
Note: If the casing is shorted or partially shorted to the pipeline,
and the potentials over the pipeline are depressed below criteria
described in Chapter 6, take immediate action to clear the short.
At all permanent reference electrodes. Also,
WATERFRONT
STRUCTURES
locate portable reference cells:
a)
Adjacent to the structure at all test stations.
b)
Every 46 meters (150 feet) along a continuous length of
sheet pile wall at both the surface and at the bottom.
c)
At other test points identified in maintenance manuals
or past surveys.
Locate the reference cell at test points identified in the
OTHER STRUCTURES
maintenance manual or other past surveys.
Annotate the soil condition (or tide level for waterfront structures)
ALL STRUCTURES
for comparison to past and future measurements.
4-7
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