What materials are often used for UST liners to enhance leak protection?

The use of high-density polyethylene (HDPE) or fiberglass-reinforced plastics as materials for UST liners is primarily based on their exceptional durability, chemical resistance, and impermeability. These materials are specifically designed to provide enhanced protection against leaks, which is critical in preventing environmental contamination from hazardous substances stored in underground tanks.

HDPE is known for its robustness and resistance to a wide range of chemicals, making it ideal for containing fuels and other toxic materials. Its flexibility also allows it to accommodate ground movement without cracking. On the other hand, fiberglass-reinforced plastics offer a combination of lightweight properties and structural strength, further reducing the risk of leaks.

In contrast, steel and aluminum, while used in some tank construction, are more susceptible to corrosion over time, particularly when exposed to moisture and aggressive chemicals. Concrete and timber do not provide the necessary chemical resistance or impermeability crucial for preventing leaks. Natural clay and stone additionally lack the necessary strength and stability as traditional liners and would not effectively contain the potential for leaks in UST systems.

Thus, HDPE and fiberglass-reinforced plastics represent the best choice for enhancing leak protection in underground storage tanks.