The advantages of using EVAPOSTOP discs compared to Internal Floating Roofs for the storage of volatile liquids is clearly shown in the table:
| Evapostop | Internal Floating Roofs | |
Potential to jam due to irregular/non- cylindrical shape |
Discs automatically conform to the shape of the tank, therefore there will be no jamming. |
Floating Roof may jam |
Flexibility for reuse in other |
Can be easily reused for other applications/ in other tanks. |
Cannot be reused |
Surface coverage |
Covers up to 99.6% of the liquid surface. |
High surface coverage, however gaps may be present due to irregular tank shape, etc. |
Maintenance issues |
Maintenance free |
Roof seal needs to be regularly maintained |
Installation downtime |
Approximately 1 day |
Approximately 3 weeks |
Installation effort |
Negligible – discs can be floated onto liquid by ha |
Large installation effort – the roof is installed in sections |
Fire Case |
Reduces fire case |
Reduces fire case |
Generation of sparks |
No sparks produced by Evapostop discs |
Aluminium internal floating roofs produce incendive sparks with jamming of roof – this may cause an internal explosion |
Hot work |
No hot work required. Screens can be bolted over nozzle openings |
Hot work required. |
Tank Utilization |
With Evapostop discs tanks can be completely utilised – no dead working volume |
Internal floating roofs have a minimum and maximum working height (typically 1 m at both top and bottom) |