A coating on the outside of a tank has an easy life compared with the one on the inside. Outside, water arrives, sits for a while and evaporates. Inside, the water never leaves. Why immersion is unforgiving In atmospheric service, small defects are tolerated. The coating dries out between rain events and damage progresses slowly. In immersion, water is working to get through the coating, around it and under it all the time. Every defect becomes a pathway. Every soluble salt l

If you own, design or maintain steel water tanks, AWWA D102 is the document the work hangs from. It is the American Water Works Association standard for coating steel water storage tanks, and it lets an engineer, a contractor and an inspector work from the same definitions. Systems, not products D102 defines coating systems in two families: Inside Coating Systems (ICS) for the interior. Outside Coating Systems (OCS) for the exterior. Each system is a generic recipe: surface p

Every potable water tank specification says the interior lining must be "NSF 61 certified." Most people read that as "safe for drinking water." That is correct, but it is only part of the picture. What NSF 61 tests NSF/ANSI/CAN 61 is a health-effects standard. The certified coating is applied and cured according to the manufacturer's instructions, exposed to water under controlled conditions, and the water is analyzed for anything that leaches out: solvents, metals, unreacted

The worst corrosion in a wastewater plant is usually where the concrete looks driest. Here is why, and what the coating has to do about it.