Double Walled Tanks
Protect the environment with advanced secondary containment tank technology
The tanks consist of a primary steel tank enclosed within a secondary steel tank. After tank installation, the 25mm interstice between the inner and outer tank is filled with a mixture of water and glycol which not only provides insulation and temperature control and will activate an alarm to alert you to a drop in pressure or liquid level.
Features
Secondary containment technology
Each tank consists of a primary steel tank enclosed within a secondary steel tank. After tank installation, the 25mm interstice (space between the inner and outer tank) is filled with a water-glycol mixture which provides insulation, temperature control, and leakage detection, and activates an alarm to alert you to a drop in pressure or liquid level.
Corrosion protection
For additional durability and protection, the outer steel wall can be coated with either:
- A 2,5mm composite (Fiberglass-reinforced Polyester Resin or FRP), or
- A 0,8mm polyurethane coating.
Convenient access and fuel dispatch
Each tank is fitted with a 745mm underground manhole or optional forecourt manhole, incorporating:
- Pump suction apertures
- Fittings for filler, dip and breather
25mm sockets on top of each end monitor the interstice. These tanks are also fitted with either lifting lugs and flanged or dished ends.
Top quality & safety standards
Manufactured in South Africa, Forgeweld’s double-walled tanks are built from Grade 335JR compliant 6mm carbon steel plate. Both the inner and outer tanks are submerged and arc welded for rugged strength. Our quality control measures are certified by the United States UL 58 standard and independent auditors.
Tank dimensions and capacity
Standard sizes for Forgeweld’s double-walled steel tanks are shown below.
Tanks can be manufactured to order. However, we recommend a maximum size of 40m3 due to the mass considerations involved in transporting double-walled steel USTs as they are heavier, or Composite USTs of the same size.
| VOLUME m³ | IN. DIAMETER MM | OUT. DIAMETER MM | OVERALL LENGTH MM | SHELL THICKNESS MM | CALC. CAPACITY liters | APPROX WEIGHT kg |
|---|---|---|---|---|---|---|
| 4.5 | 1810 | 1817 | 2050 | 6 | 4515 | 2090 |
| 9 | 1810 | 1817 | 3650 | 6 | 9024 | 3054 |
| 14 | 1810 | 1817 | 5350 | 6 | 13876 | 4017 |
| 23 | 2318 | 2330 | 5350 | 6 | 22442 | 5027 |
| 30 | 2318 | 2330 | 6100 | 6 | 29515 | 6265 |
| VOLUME m³ | IN. DIAMETER MM | OUT. DIAMETER MM | OVERALL LENGTH MM | SHELL THICKNESS MM | CALC. CAPACITY liters | APPROX WEIGHT kg |
|---|---|---|---|---|---|---|
| 4.5 | 1810 | 1817 | 2050 | 6 | 4515 | 2090 |
| 9 | 1810 | 1817 | 3650 | 6 | 9024 | 3054 |
| 14 | 1810 | 1817 | 5350 | 6 | 13876 | 4017 |
| 23 | 2318 | 2330 | 5350 | 6 | 22442 | 5027 |
| 30 | 2318 | 2330 | 6100 | 6 | 29515 | 6265 |