DirecTank Environmental Products

Capacity+ Low Profile Secondary Seal

Capacity+ Low Profile Secondary Seal

Optimised secondary sealing for applications with limited vertical clearance
Secondary sealing solution engineered to maximise usable tank capacity while maintaining effective vapour control and reliable performance across a range of operating conditions.

Overview

The Capacity+ Low Profile Secondary Seal is a high-performance secondary sealing solution designed for floating roof tanks where vertical clearance is limited and optimisation of usable working capacity is critical.
By combining a low vertical profile with a wide horizontal working range, the Capacity+ enables operators to optimise usable tank volume without compromising sealing integrity. Installed between the floating roof and the tank shell, the seal works in conjunction with the primary seal to further reduce vapour emissions and support regulatory compliance.
Manufactured using robust, spring-steel mechanical components and a PTFE-wrapped wiper tip, the Capacity+ is engineered to perform reliably across variable rim gaps, challenging tank shell conditions, and demanding operating environments.

Design Highlights

Low vertical profile to optimise usable product capacity
Wide horizontal working range to accommodate variable rim gaps
PTFE-wrapped wiper tip for enhanced abrasion resistance and chemical compatibility
Spring-steel mechanical components engineered for long service life
Suitable for installation in-service or out-of-service
Compatible with a range of vapour barrier fabric options

Key Benefits

Maximises tank
working capacity

The low-profile design allows operators to recover usable storage volume that may be constrained by higher-profile secondary seals.

Reliable sealing across variable rim gaps

Engineered to maintain consistent contact with the tank shell across rim space variability and shell irregularities.

Reduced vapour emissions

Provides an additional sealing layer that limits vapour escape and supports environmental performance objectives.

Durable, low-maintenance construction

Robust materials and spring-backed components deliver dependable, low-maintenance operation.

Flexible in-service and
out-of-service installation

Designed for safe and efficient installation during both in-service and out-of-service conditions.

Compliance and Standards

The Capacity+ Low Profile Secondary Seal is suited to floating roof tanks where vertical clearance constraints and performance demands intersect, including:

Compliance & Quality

Capacity+ secondary seals are manufactured under DirecTank’s quality management system and developed in line with recognised industry standards and regulatory requirements.
Materials are fully traceable, and designs support compliance with applicable air quality and emissions control regulations, including classification as a Category “A” secondary seal where required.
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