The Primary Master Seal is a hybrid primary sealing system designed for external floating roof tanks (EFRTs). It combines the advantages of both mechanical shoe seals and compression (foam or fabric) seals, offering robust vapor control and adaptability to tank wall irregularities. This design features rigid metallic components (shoes or plates) backed by resilient flexible elements that maintain continuous contact with the inner tank shell, even as the roof moves with the liquid level.
The master seal provides tight and durable sealing around the annular space between the tank shell and the floating roof, significantly reducing vapor losses and ensuring environmental compliance.
Superior Sealing Performance: Combines mechanical contact and flexible compression for maximum efficiency.
Enhanced Emissions Control: Highly effective in preventing the release of VOCs from storage tanks.
Tank Shell Conformity: Adapts to out-of-round conditions and shell irregularities.
Long Service Life: Durable materials and hybrid construction increase seal longevity.
Regulatory Compliance: Meets or exceeds international emission standards (e.g., EPA, API).
Safe for Flammable Products: Reduces fire and explosion risk by minimizing vapor escape.
Primary Hybrid Seal (Master Seal) combining mechanical and compression elements
Storage of high-volatility hydrocarbons such as gasoline, crude oil, benzene, toluene
Large diameter tanks requiring superior emission control
Retrofit projects where tank roundness is a challenge
Tanks operating in harsh weather environments with frequent roof movement
Oil & Gas (Upstream, Midstream, Downstream)
Petrochemical
Bulk Fuel Storage
Chemical Processing
Aviation Fuel Terminals
| Feature | Specification / Options |
|---|---|
| Seal Type | Primary Hybrid Master Seal |
| Material | Stainless steel shoe plates + elastomeric or fabric-reinforced compression seal |
| Seal Height | Adjustable to tank rim configuration |
| Seal Compression | 10–30% for foam-filled section |
| Operating Temperature | -20°C to +85°C (optional up to +120°C) |
| Seal Lifetime | Typically 10+ years |
| Chemical Resistance | Excellent against hydrocarbons, UV, and weathering |
| Compliance | API 650, API 652, ISO 28300, EPA 40 CFR 60 Subpart Kb |
Inspection: Check the floating roof and shell for damage or misalignment.
Shoe Assembly: Install metallic shoes along the roof rim, ensuring proper spacing and curvature.
Compression Seal Mounting: Attach foam or elastomeric elements behind the metal shoes.
Wiper Installation: Affix wiper tip material to the top or bottom edge to maintain vapor-tight contact.
Functional Test: Perform a roof movement test to confirm continuous sealing.
Routine Inspections: Every 6–12 months for metal corrosion, wiper wear, or seal misalignment.
Seal Compression Checks: Ensure foam or elastomeric elements retain proper contact and spring tension.
Wiper Replacement: Periodic replacement of worn or hardened wiper tips to maintain integrity.
Hardware Tightening: Re-torque fasteners and brackets as needed to maintain seal position.
VOC Emission Reduction: High sealing efficiency helps meet Clean Air Act and EU VOC limits.
Product Conservation: Minimizes evaporation losses, saving valuable hydrocarbon products.
Fire Risk Mitigation: Prevents accumulation of flammable vapor clouds at tank roof level.
Durable Components: Long life reduces frequency of material replacement.
Modular Design: Damaged parts can be replaced individually, reducing waste.
Passive System: No electricity or external power needed.
Recyclable Materials: Steel and aluminum components can often be recycled at end of life.
Metallic Waste: Shoe plates and hardware, if not recycled, can contribute to landfill burden.
Elastomer Disposal: Non-biodegradable; should be disposed of per environmental guidelines.
