Storage tanks are typically carbon steel with an internal lining to prevent internal corrosion. This is usually less expensive than using a higher-grade tank material, such as stainless steel or Cu-Ni, without a lining. Metal plating is seldom used as a lining material anymore, as advances with other lining materials s make them better suited for the application.
Water chemistry and temperature are the two greatest influences on the serviceable life of a tank lining, with the greater the storage temperature, the greater the likelihood of corrosion occurring.
The ASME Boiler and Pressure Vessel Code, Section IV, lists the most common lining materials for use with potable water storage, along with some minimum criteria for their application:
- Cement Linings – RECO USA uses Pre-Krete exclusively for our cement linings. It is NSF Standard 61 certified and was developed specifically to protect steel surfaces from the corrosive effects of hard or soft water in ambient and hot storage vessels. The lining material is applied by hand, generally to a about a ¾” thickness. Cement linings provide excellent coverage, without pinholes or discontinuities, and are fully field repairable.
- Epoxy Linings – Epoxy linings are applied by hand rolling or spraying. It is a multi-coat process with a final dry film thickness of 8 to 12 mils. They are generally limited to water temperatures below 120 ° but like our cement lined tanks, all RECO USA epoxy lined tanks are NSF 61 compliant and field repairable.
- Glass Linings – This type of lining is most often used in residential and smaller, throw-away commercial tanks. Glass linings involve a multi-coat process that requires heating in a furnace to 2,500 F to fuse the glass to the tank interior surface, with a resulting thickness of 5 mils or more. And unlike cement or epoxy lined tanks, glass lined tanks require a sacrificial anode for corrosion protection and they cannot be field repaired.
The ultimate choice of tank lining materials will depend on many factors relating to the application, as well as project economics. RECO USA has been building storage tanks in above-ground, underground, vertical, horizontal, and lined or unlined configurations for many years. For any questions regarding the right choice of lining or tank material, feel free to contact us.