Factors That Effect The Life Of An Oil Tank:
Acidity of soil (ph): The value of the soil will indicate the acidity or alkalinity contained in the soil which can be corrosive to the tank and lines.
Sulfide (bacteria) content: In certain soils, a type of bacteria exists which requires no oxygen in its life process. This particular type of bacteria does not attack metal directly, but in its life process changes sulfates, which occur naturally in the soil, into sulfides.
Moisture content is a good indicator of corrosiveness of the soil. While there is enough moisture universally present to support limited electrolytic activity, the amount of activity is in proportion to the moisture content of the soil (i.e.) a high water table.
Seasonal ground movement: During severe winters with long stretches of sub-freezing temperatures, the soil will freeze or constrict, thus a slight movement of the tank may occur. When the spring thaw occurs, a secondary movement is possible as the ground expands and softens up.
Seismic activity: In many areas of the country there is almost a continual subterranean movement, due to seismic activity. This movement is not readily felt but could be damaging (?) top a line or tank.
The human factor, the one we can most control. However, during tank installation, if the excavation is filled with a coarse material and the tank is placed in such conditions, then seasonal ground movement and seismic activity will adversely affect the life of the tank, as stated above.
Oil spillage from oil tank corrosion due to above factors
Example of soil contamination from in-ground oil storage tank leak. Note the soil color is gray from oil seeping into the soil.