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Engineered roof drainage system for external floating roof applications

Roof Drain Technology

Engineered roof drainage systems for external floating roofs.

Introduction

​​WLI provides engineered roof drainage technology for external floating roofs in aboveground storage tanks. Our scope includes drainage concept development, hydraulic calculation, component selection and the supply of project-specific roof drainage equipment.

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The WLI roof drainage portfolio includes TRUE roof sump / drain valve technology, PURE roof drain swivel joints, roof drain piping and complementary drainage components. Each system is designed according to the actual tank geometry, roof design, rainfall requirements, operating conditions and project-specific drainage concept.

Complete Roof Drain Systems

Project-specific drainage solutions for external floating roofs.

External floating roof drainage is not just a matter of individual components. Reliable performance depends on the correct combination of roof geometry, drainage port location, drain valve technology, swivel joint configuration, piping layout and hydraulic capacity.

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WLI supports tank operators with engineered roof drain systems designed to remove rainwater safely and reliably from external floating roofs.

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Typical scope includes:

  • Roof drainage concept development

  • Hydraulic calculation of roof drain systems

  • Selection of roof drain components

  • TRUE roof sump / drain valve technology

  • PURE roof drain swivel joints

  • Stainless steel roof drain piping

  • Retrofit concepts for existing external floating roofs

  • Documentation for engineering review and project handover

TRUE roof sump and automatic drain valve for external floating roof drainage systems

TRUE Roof Sump / Drain Valve

Integrated roof sump and automatic drain valve technology.

TRUE is designed for floating roof drainage applications where reliable drainage and automatic backflow protection are required.

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The TRUE valve body drains residual water into the connected roof drain system. In case of product backflow from the roof drain system, the rising liquid level inside the TRUE valve body lifts the floater against the sealing package and closes the drain path automatically.

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The hydrostatic pressure of the stored product supports reliable sealing until the operator closes the manual shut-off device.

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Key features:

  • Integrated roof sump / drain valve with automatic float check valve.

  • Designed to drain residual water from the TRUE valve body into the connected roof drain system.

  • Automatic float-actuated closure in case of product backflow.

  • Low-resistance drainage path for rainwater discharge.

  • Corrosion-resistant stainless steel body.

  • Welded or bolted installation depending on floating roof design and project requirements.

  • Adaptable to existing floating roof designs subject to project-specific interface checks.

  • Project-specific material selection according to stored product, drain water composition and chemical environment.

Download TRUE Product Information

PURE roof drain swivel joint for external floating roof drainage piping system

PURE Roof Drain Swivel Joint

Roof drain swivel joint technology for floating roof movement compensation.

PURE roof drain swivel joints are designed for external floating roof drainage systems where the roof drain piping must follow the vertical movement of the floating roof during tank operation.

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The swivel joint configuration is selected according to tank diameter, roof travel, pipe routing, drainage capacity and project-specific operating requirements. In combination with TRUE and engineered roof drain piping, PURE supports reliable rainwater removal from external floating roofs.

 

Key features:

  • Roof drain swivel joint technology for external floating roofs

  • Movement compensation during floating roof travel

  • Integration into project-specific roof drain piping systems

  • Stainless steel construction according to project requirements

  • Suitable for new-build and retrofit applications

  • Designed for reliable and maintenance-friendly drainage system operation

  • Compatible with TRUE roof sump / drain valve technology

Download PURE Product Information

Roof drain system engineering and hydraulic calculation for external floating roofs

Engineering & Calculation

Drainage systems engineered according to actual tank and operating conditions.

WLI roof drain systems are engineered according to the actual application. The drainage concept is based on tank geometry, roof design, rainfall intensity, roof slope, drainage port location, pipe routing and the required hydraulic capacity.

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Typical engineering inputs include:

  • Tank diameter and tank height

  • Floating roof type and roof travel

  • Roof slope and drainage port location

  • Rainfall intensity and design drainage capacity

  • Roof drain pipe routing

  • Required nominal pipe diameter

  • Stored product and chemical environment

  • Material requirements

  • Existing roof sump and roof drain configuration

  • Retrofit constraints and shutdown conditions

Retrofit of external floating roof drainage system with TRUE and PURE components

Retrofit Applications

Upgrading existing external floating roof drainage systems.

Many existing external floating roofs are equipped with conventional roof sumps and aging roof drain systems. WLI supports retrofit projects where drainage performance, residual water removal, corrosion resistance, operational reliability or maintainability need to be improved.

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In retrofit applications, TRUE can replace the existing roof sump, while PURE swivel joints and new drain piping can be integrated into the upgraded drainage system.

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Retrofit scope may include:

  • Assessment of existing roof sump and roof drain system

  • Replacement of conventional roof sump arrangements with TRUE

  • Integration of PURE roof drain swivel joints

  • Modification or replacement of roof drain piping

  • Hydraulic review of the existing drainage concept

  • Installation support during tank shutdowns

  • As-built documentation after completion

Roof drain technology project execution from engineering to installation support

Project Execution

From drainage concept to installation support.

WLI supports roof drainage projects from the initial technical assessment through engineering, supply, installation support and documentation. Depending on the project scope, WLI can provide individual components or complete engineered roof drainage systems.

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Project support includes:

  • Technical assessment and concept development

  • Engineering and calculation of the roof drain system

  • Component selection and supply

  • Installation planning and shutdown coordination

  • Turnkey installation support where required

  • Functional review and handover documentation

  • As-built documentation after completion

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