Page 167 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

HAZARDOUS MATERIALS STORAGE 145

Zone 1.
Atmospheric
corrosion
Zone 2.
Splash zone
above high
tide Mean high tide
Zone 3.
Tidal
Mean low tide
Zone 4.
Continuously
submerged
Mud line

Zone 5.
Subsoil

Relative loss in metal thickness
Figure 3.13 Corrosion profile of steel piling after 5-year exposure to seawater (7).

3.10 HAZARDOUS MATERIALS STORAGE

Bulk storage of hazardous liquid and gaseous materials is usually done in large steel
tanks. The largest aboveground tanks are used at refineries and manufacturing plants.
These range from 15 m (50 ft) to more than 61 m (200 ft) in diameter with a capacity
3
of more than 3785 m (1 million gallons). Transportation and distribution terminals of
storage facilities for these materials can have a mix of aboveground and underground
tanks. Liquid petroleum products at the point of sale and at the point of use are stored
3
in direct buried underground tanks ranging from 1.9 to 114 m (500–30,000 gallons)
in capacity. Gases are typically stored in similarly sized aboveground tanks at the
point of use. Hazardous chemicals are usually stored in vaulted underground tanks
or aboveground facilities. Storage tanks for pressurized materials can be spherical in
shape while storage tanks for unpressurized materials can be constructed from welded
plate (Fig. 3.14a, b).

3.10.1 Aboveground Storage Tanks
Large steel aboveground storage tanks (ASTs) are located on large tank farms of oil
producers (Fig. 3.15). Maintenance teams take care of external painting and both
internal and external corrosion inspections. Corrosion inspection and protection of
ASTs is important for the preservation of large capital investments, the reduction of
maintenance and inspection costs, and the assurance of system integrity for release