The biggest concern that owners of potable water storage tanks must contend with is the problem of corrosion and how to combat it.
It is a topic that corrosion engineers consider daily, their entire careers being built on understanding how it happens and what can be done to prevent or slow it.
To fully grasp the complexity of the problem and the importance of adequate water storage tank maintenance, tank owners should understand this, too.
Fact About Metal Corrosion
There are four important factors to understand about metal corrosion to fully acknowledge how water storage tanks rust and what has to be done to prevent it:
- The only metals that can corrode are those containing iron or iron oxide; the higher the iron content is, the faster, and more easily the metal will corrode.
- Corrosion is caused by oxidation, and the result of oxygen and water together being in contact with iron-containing metals.
- Environmental conditions like temperature, humidity, and electrical conditions can affect how quickly iron-containing metals will oxidize.
- Metal thickness combined with iron content also affects how quickly an iron-containing metal will begin corroding; higher-content, thinner metals that are uncoated can start with surface corrosion in as little as 5 days.
Water Storage Tank Design
Based on these four simple factors, corrosion engineers design water storage tanks, protective tank coatings, and tank protection and maintenance techniques to withstand the conditions that cause corrosion.
Every tank design is affected by water and oxygen in some way, whether due to the metal being in constant contact with water on the inside or due to high humidity, salt air, high temperatures on the outside, multiple types of metals that interact with each other and the water, etc.
There are countless reasons why corrosion due to oxidation can begin with water storage tanks, as thick and durable as they may seem to be.
Bringing Needs and Design Together
Considering all of this, it is essential that tank owners understand what tank design will serve their needs best, what kind of protective coatings can prevent exposure to oxygen longer and more thoroughly, and whether alternative measures like cathodic protection should be used as well.
Coatings, regular draining and cleaning, sludge removal, and cathodic protection all fall under critical water storage tank maintenance designed to prevent oxygen and water from acting on the metal and causing corrosion.
With water storage tank conditions conducive to allowing corrosion to begin in as little as a few weeks, tank owners must take their tank selection and maintenance very seriously to slow the course of oxidative corrosion.