MC-99-87 Alternatives to Double Bottom Tanking

Description:

In the past double bottom tanking has been used for many reasons. The main reason this is done is to repair a tank floor that has failed for one reason or another. Causes of failures include fatigue from many years of flexing, to corrosion on the bottom side or interior of the tank. Double bottom tanking, logically, is done to repair the tank floor and return the tank to service. This gives what is believed to be an added measure of protection. In reality, this gives a false sense of security by thinking that the problem is repaired. Actually, the problem is only moved to the new floor. Because the old floor is under the new floor, adequate cathodic protection can not be applied to the underside of the new floor.