Terminal · Storage
Secondary Containment
The dikes or berms and the lined floor around a group of tanks that hold a spill if a tank or its piping fails.
What it does
Keeps a release inside the tank area and away from soil and groundwater. Under AER Directive 055 a dike around one tank holds at least 110 percent of it; around several tanks it holds the largest tank plus the larger of 10 percent of that tank or 10 percent of all the others. Collected fluids are not released until tested.
Basics
| Built as | Dike with an impervious liner (clay or synthetic) |
| One tank (AER D055) | At least 110% of its capacity |
| Several tanks | Largest tank plus 10% of it or of all others, whichever is larger |
| Collected fluids | No discharge before testing |
Common failures
- Collected fluid released without testing, carrying oil off site
Troubleshooting
- Symptom
- Sheen on water collected inside the dike
- Likely cause
- Oil from a leak inside the containment
- What to check
- Do not release; find the source, recover the oil and test before any discharge