Designed to maintain internal pressure balance and prevent vapour buildup, rim vents play a critical role in floating roof tanks equipped with sealing systems. Prime Tank Systems’ rim vent solutions ensure safe ventilation, reduce the risk of vacuum or overpressure conditions, and support environmental emission control.
Pressure Regulation for Sealed Rim Spaces
At Prime Tank Systems, our Rim Vent units are engineered for use on floating roof tanks equipped with sealed rim spaces—typically where mechanical shoe seals or double wiper seals are applied. These configurations form a vapor pocket around the deck perimeter, necessitating controlled pressure equalisation.
Our rim vents connect directly to the rim vapor space—enclosed by the deck rim, seal shoe, primary seal fabric, and liquid surface—via dedicated piping. They are designed to release excess pressure or vacuum, maintaining both structural integrity and environmental compliance.
Most rim vent models feature weighted pallet assemblies seated on gasketed surfaces, offering reliable passive operation under fluctuating internal conditions.
Depending on the tank configuration:
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Single-deck internal floating roofs may require a PVRV (Pressure Vacuum Relief Valve),
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While double-deck or spider deck roofs with shallow sinking depths typically use PRVs (Pressure Relief Valves) only.
Each rim vent is custom-dimensioned to suit the specific tank geometry and regulatory requirements.
Available Configurations
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PVRV Rim Vents (2” to 14” diameter)
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PRV Rim Vents (2” to 12” diameter)
Tank Breathing Safety
Rim vents allow excess vapour pressure to safely escape from the tank annular space, preventing overpressure or vacuum conditions. This ensures the tank remains structurally sound and compliant with emission regulations.
By controlling vapour release through a designed path, rim vents help reduce fugitive emissions and ensure vapours are not vented uncontrolled into the atmosphere. This aligns with global environmental standards.
For floating roof tanks with sealed rim spaces, rim vents are strongly recommended and often required by industry codes to ensure safe pressure equalisation during tank operations and weather changes.
