Roof Drain Technology

Engineered roof drainage system for external floating roof applications

Engineered roof drainage systems for external floating roof applications.

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.

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.

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

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 combines the roof drainage port, integrated sump function and automatic drain valve in one compact component. Unlike conventional roof sump arrangements, where rainwater is collected in a welded sump box before entering the drain inlet, TRUE allows water to drain directly from the floating roof membrane into the valve body and further into the roof drain piping system.

This design is intended to minimize residual water around the drainage port and support reliable rainwater removal from external floating roofs. In retrofit applications, the existing roof sump can be removed and TRUE can be installed in its place.

Key features:

Integrated roof drainage port, sump function and automatic drain valve
Direct water flow from the roof membrane into the valve body
Designed to minimize residual water at the drainage point
Retrofit replacement for conventional roof sump arrangements
Automatic drain valve function for external floating roof drainage systems
Stainless steel construction according to project requirements
Integration into complete roof drain systems with PURE swivel joints and drain piping
Project-specific engineering according to roof geometry, rainfall data and drainage concept

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.

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

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.

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.

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.

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

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.

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