Terminal · Storage
Internal Floating Roof
A fixed roof tank with a light deck inside that floats on the liquid and rises and falls with the level.
What it does
The floating deck almost removes the vapor space above the liquid, cutting evaporation, while the fixed roof keeps rain, snow and wind off the deck. Common for gasoline, condensate and other volatile products, and as a retrofit of fixed roof tanks.
Basics
| Deck | Contact or noncontact, floats on the liquid |
| Roof above | Column supported or self supporting |
| Seal | Rim seal between deck and shell |
| Losses | Rim seal, deck fittings and deck seams |
Common failures
- Deck that tilts, sinks or hangs up on a column, losing the vapor control
Troubleshooting
- Symptom
- Vapor detected above the deck at the roof vents
- Likely cause
- Damaged rim seal or deck fitting
- What to check
- Inspect the seal and fittings at the next out of service inspection