02.01 Which is preferred – fiberglass or steel underground tanks?

Both fiberglass and steel tanks are widely used for emergency generator applications. Both are built to UL standards and are inspected and certified by UL procedures. The steel tanks are typically a composite design that includes a fiberglass secondary containment that also provides corrosion protection.

Fiberglass tanks are manufactured by 2 primary US manufacturers: Xerxes Corporation, and Containment Solutions (the old Owens Corning brand). Steel tanks are manufactured by a relatively large number of manufacturers, typically local or regional firms, and typically members of the Steel Tank Institute. Modern Welding is the only national steel tank manufacturer, and Highland tank is a prominent manufacturer serving the East and Midwest.

In general, fiberglass manufacturers promote corrosion-proof designs, and steel tank manufacturers promote higher strength and chemical compatibility for future fuels.

The price comparison between fiberglass and steel tanks varies in time and place, based on oil chemical prices, steel prices, and freight prices. In general they are comparable.