These all-fiberglass tank constructions may be primary (single wall), secondary (double wall) or tertiary (triple wall) types, and are suitable for containment of general fuels and similar flammable and combustible liquids, as identified in the (# or ++) liquid ratings for tanks constructed and investigated to either of the UL 1316 Standard versions below.
UL 1316, “Glass-Fiber-Reinforced Plastic Underground Storage Tanks for Petroleum Products, Alcohols, and Alcohol-Gasoline Mixtures” (until February 28, 2023):
Nonmetallic underground tank for (#) — A primary fiberglass tank with one or more compartments.
($) secondary-containment nonmetallic underground tank for (#) — A primary fiberglass containment tank wrapped within an external fiberglass shell that provides both secondary containment and interstitial monitoring.
Tertiary-containment nonmetallic underground tank for (#) — A Type I or Type II secondary-containment fiberglass tank completely contained within an external fiberglass shell that provides both tertiary containment and interstitial monitoring.
UL/ULC 1316, “Fibre Reinforced Underground Tanks for Flammable and Combustible Liquids”:
Fiberglass (+) Underground Tank for (++), where:
(+) = “Single Wall” (or “SW”), “Double Wall” (or “DW”) and “Triple Wall” (or “TW”), as applicable.
(++) = “Petroleum Products, Oxygenates, and Oxygenated Fuels, E0 to E100, B0 to B100 at ambient temperatures, and #6 Fuel OiI up to (&),” and any optional fuels based on individual testing. This single new UL/ULC 1316 fuel rating generally combines the three old UL 1316 individual fuel ratings under Liquid Ratings below, as it requires material compatibility testing with new aggressive test fuels to support it, plus adds options for other fuels based on individual testing. See UL/ULC 1316, Appendix A, for further guidance.(&) maximum rated temperature based on individual testing.