MIL-HDBK-1004/10
g)
Anode distribution:
(1)
Area of pipe protected by one anode:
A = 7,264/43, total area divided by number of anodes
A = 169 ft/anode
(2)
Division of anodes:
Laterals
4,994/169
=
30 anodes
Header
1,860/169
=
11 anodes
Supply and return lines
410/169
=
2 anodes
Steel Sheet Piling in Seawater (Galvanic Anodes). Galvanic anode
9.10
cathodic protection is provided for a 1,000-foot-long steel sheet piling
bulkhead as shown in Figure 113. The well coated bulkhead has been installed
and the capability for underwater welding is not available for attachment of
the anodes directly to the structure.
9.10.1
Design Data
a)
Seawater resistivity - 22 ohm-cm.
b)
Soil resistivity on front side of bulkhead - 250 ohm-cm.
c)
Soil resistivity on shore side of bulkhead - 1,000 ohm-cm.
d) Design for 0.5 mA/ft for area below high tide level, 0.2
mA/ft in mud at front face of bulkhead, and 0.05 mA/ft in the soil on the
shore side of the bulkhead.
e) Type III aluminum anodes, buried at the base of the bulkhead
will be used to protect the front side of the bulkhead as direct attachment to
the bulkhead by welding is not possible.
f) 50-pound standard alloy magnesium anodes will be used to
protect the shore side of the bulkhead.
g)
Design for 15-year anode life.
h) The electrical continuity between sections is not reliable and
bonding will be required.
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