1. Primary Inner Tank Materials
- Carbon steel – widely used for waste oil and general industrial liquids; good strength and lower cost.
- Stainless steel – selected when higher corrosion resistance is required.
- High‑density polyethylene – chosen for broader chemical compatibility and lighter weight.
- Material selection should always match the stored waste oil type.
2. Secondary Outer Containment Materials
- Common materials: carbon steel, fiberglass reinforced plastic (FRP), and high‑density polyethylene.
- Steel outer shells – typical for UL 142 listed aboveground tanks.
- FRP – often used for underground or SF type tanks because it resists soil corrosion.
- Polyethylene outer walls – common in plastic double‑wall tanks for chemical storage.
3. Interstitial Space & Monitoring Components
- Interstitial space between inner and outer walls for leak detection.
- May contain air, vacuum, inert gas, or a monitoring fluid.
- Leak detection ports, sensors, monitoring tubes, and alarm systems are installed.
- Allows operators to detect inner wall failure before waste oil escapes into the environment.
4. Coatings, Insulation & Fittings
- External surfaces protected with epoxy primer, polyurethane topcoat, or other industrial coatings.
- Fire‑protected tanks may include concrete, foam, or lightweight fireproofing materials.
- Fittings: fill ports, vents, level gauges, drain valves, and emergency vents.
- Fittings made from steel, stainless steel, or compatible polymers.
- Material selection must match installation environment and local regulatory requirements.