The Primary Foam Type Roof Sealing System is a flexible, compressible sealing solution used on External Floating Roof Tanks (EFRTs) to reduce vapor emissions from the annular space between the floating roof and the tank shell. This system consists of a foam-filled tubular or rectangular elastomeric envelope, which is compressed between the roof rim and the inner tank wall. The foam material ensures consistent expansion and surface contact, accommodating tank roundness variations and roof movements.
This seal is considered a lightweight, cost-effective solution ideal for tanks with less demanding operational conditions or where moderate vapor retention is acceptable.
Cost-Effective Solution: Lower installation and material cost compared to mechanical shoe or pantograph seals.
Easy to Install: Lightweight components and minimal mechanical parts simplify installation.
Flexible Fit: Conforms easily to tank wall irregularities and out-of-roundness.
Low Maintenance: No moving mechanical parts, which reduces inspection and repair needs.
Effective for Moderate VOC Control: Reduces emissions in applications with lower volatility or less strict regulations.
Primary Foam Seal – Compressible foam core with an elastomeric cover
Storage of distillates such as kerosene, diesel, and heating oil
Crude oil tanks with minimal sloshing or internal turbulence
Biofuel and ethanol storage
Water and wastewater treatment tanks
Facilities requiring interim emission control measures
Oil & Gas
Fuel Terminals
Refineries
Water Treatment
Biofuels & Chemicals
| Feature | Specification / Options |
|---|---|
| Seal Type | Primary Foam-Filled Seal |
| Core Material | Polyurethane or closed-cell polyethylene foam |
| Outer Cover | Nitrile rubber |
| Seal Profile | Rectangular cross-section |
| Seal Width | Typically 100–200 mm (customizable) |
| Foam Density | Medium to high density (24–32 kg/m³ typical) |
| Tank Diameter Range | Up to 130 meters |
| Temperature Range | -20°C to +70°C (extended options available) |
| Compliance Standards | API 650 Appendix H, API 652, EN 12285, ISO 28300 |
| Seal Performance | Suitable for low to moderate volatility products |
Performed during initial tank construction or maintenance shutdown.
Foam tube or pad is inserted into the annular gap between the floating roof rim and the tank wall.
Secured to the roof rim using retainers, straps, or tension cords.
No welding or complex mechanical fitting required.
Visual Inspection: Periodic checks (typically annually) for surface wear, chemical degradation, or loosening.
Seal Integrity: Inspect for loss of elasticity, tears in the outer fabric, or exposure of the foam core.
Replacement Cycle: Typically 5–8 years depending on tank service conditions and stored product.
VOC Emission Reduction: Offers basic to moderate control of hydrocarbon vapor emissions.
Odor Control: Helps mitigate odor release from lighter distillates and organic liquids.
Improves Tank Safety: Reduces vapor accumulation in the tank’s headspace.
Lightweight Materials: Lower embedded energy in production compared to metal-based seals.
Recyclability: Foam materials are generally not recyclable, but elastomeric covers may be repurposed.
Passive Operation: No energy input needed—seal works by passive mechanical compression.
Shorter Life Cycle: Requires more frequent replacement than mechanical seals, resulting in more material turnover.
Not recommended for high-volatility products like gasoline or naphtha due to limited vapor-tightness.
Can degrade over time under UV, extreme temperatures, or chemical exposure if not properly maintained.
