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 INTERIM DESIGN CRITERIA
EM
CATHODIC PROTECTION SYSTEMS
April 1994
1. Provide Cathodic Protection Systems (CPS) and protective coatings for the
following buried or submerged metallic utility systems regardless of soil or
water corrosivity:
a.
Natural gas pipelines
b.
Petroleum, Oil and Lubricant (POL) pipelines
c.
Oxygen pipelines
d.
Underground POL and gasoline storage tanks
e.
Underground hazardous substance storage tanks
f.
All water storage tanks interiors
2. Consider CPS in conjunction with other protective measures such as
material thickness incrementation, protective coatings and encasement for the
following waterfront metallic structural systems:
a.
Steel sheet piling bulkheads
b.
Steel bearing piles for piers
C.
Steel fender piles for piers
d.
Mooring Components
In marine environments, CPS are most effective and can greatly extend the
life of the submerged zones of steel waterfront structures. The splash and
atmospheric zones will require reapplication of coatings and encasements for
maximum system service life. Partial concrete encasement of steel piles
creates a zone of high potential at the concrete encasement-to-bare steel
pile interface where submerged. CPS should be provided in these
circumstances in addition to the partial encasement
3. Install CPS for the exterior bottoms of steel above ground POL storage
tanks (AST) with or without impervious liners unless field tests and
inspections by a qualified corrosion engineer indicate the environment to be
non-corrosive. Existing tanks with bottoms on oil-filled sand pads on
plastic liners are not necessary. However, when these tank bottoms are
replaced, provide CPS unless field tests and inspections by a qualified
corrosion engineer indicate the environment to be non-corrosive.
4. Provide CPS and bonded protective coatings on other buried or submerged
new steel, ductile iron, or cast iron utility pipelines not mentioned above
when the resistivity is below 30,000 ohms at the installation depth at any
point along the installation. Do not use unbonded protective coatings such
as loose polyethylene wraps. Provide joint bonding on all ductile iron and
cast iron installations.
Enclosure (1)
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