Technical Guide for Aluminum Geodesic Dome RFQ

3. Accessories and Additional Components

3.1 Functional Accessories:

• Hatches, manholes, skylights, vent.

• Stairs, walkways or platforms.

• Flashing or seals for pipe penetrations.

• Pipe supports for fire protection systems (if required).

• IFR guide assemblies.

3.2 Optional Items

• Top work platform and center platform.

• Access to dome accessories.

• Additional manholes and nozzles.

• Anti-rotation nozzles for IFR.

3.3 Safety Components:

In tanks with low internal pressure: pressure/vacuum valves (API 2000) and emergency vents (VRV).

4. Maximum Design Internal Pressure

According to API 650 – Appendix G (Section G.4.3 Internal Pressure):

“Unless otherwise specified by the Purchaser, the internal design pressure shall not exceed the weight of the roof. In no case shall the internal design pressure exceed 2.2 kPa (9 in. of water). When the design pressure, Pmax, for a tank with an aluminum dome roof is being calculated, the weight of the roof, including structure, shall be used for the DLR term in F.4.2.”

WB aluminum geodesic domes are designed for atmospheric and low-pressure tanks in accordance with API 650 Appendix G, with:

• Maximum internal pressure: +2.2 kPa (≈ 0.32 psi ≈ 9 in H₂O)

• Maximum vacuum pressure: –0.5 kPa

Higher values require special design by the manufacturer.

5. Types of Shoe Structures

World Bridge offers several types of connection between the dome and the tank wall:

• Sliding Type: allows thermal movements and minimizes loads on the tank wall.

• Bolting Type: Rigid bolted connection, used in pressurized tanks.

• Hinge Type: WB's standard lightweight articulated structure with the best cost-to-weight ratio.

• Advanced Bolting Type: modular system without welding, ideal for quick assemblies or retrofits.

WB recommendation: use Hinge Type as standard and Sliding Type when seeking to minimize the loads on the tank shell.

6. Tension Ring

The tension ring is a structural component that resists circumferential forces generated by the dome and provides the necessary stiffness at the tank’s top edge.

There are two main configurations depending on the project design:

6.1. Carbon Steel Tension Ring (CS Tension Ring)

This is, in most cases, the recommended option.

Designed and installed by the tank manufacturer. Provides stiffness, prevents deformation, and allows for a lighter and more economical dome.

Possible configurations:

• Thick annular or polygonal plate

• Wind girder near the tank top

Local reinforcement (if required):

• Load-distribution plates

• Local structural reinforcements based on analysis

1. Introduction

Aluminum Dome Roofs (ADRs) are lightweight, corrosion-resistant, self-supporting structures designed in accordance with API 650 Appendix G.

Manufactured by World Bridge Industrial Co., Ltd., ADRs offer an efficient and durable solution for covering storage tanks for hydrocarbons, petrochemicals, or water. Its screw-on design without welding allows for quick assembly, low structural weight and minimal maintenance.

In order to obtain an accurate and optimized technical offer, it is essential to correctly specify the tank data, operating conditions and required accessories.

2. General Information to be Provided

When requesting a Request for Quotation (RFQ) for an aluminum geodesic dome, it is recommended to include the following technical and design information:

2.1 General Tank Data

• Project name, client and location (country).

• Internal diameter and height of the tank.

• Type of tank (new or existing).

• Type of construction (welded or bolted).

• Stored product.

• Design and operating pressure.

• Design and operating temperature.

• Maximum inlet and outlet flow

• Maximum and minimum liquid level.

• Design standard (API 650/EN 14015/AWWA/other).

• Design standard for wind and basic wind speed.

• Live load and snow load applicable according to location.

• Seismic zone or spectral accelerations.

2.2 Required Structural Details

• Top angle dimensions and characteristic: thickness, material, height and shape of connection.

• Wind girder dimensions (if applicable), especially if used as a perimetral platform or walkway.

• Type of tension ring.

  • Carbon steel tension ring fabricated by the tank manufacturer (option normally used) or

  • Aluminum tension ring integrated into the dome structure

• Type of support or shoe (sliding, bolting, hinge, advanced bolting). (see point 5)

Details of Top Angle and Wind girder

Carbon Steel Tension Ring

6.2. Aluminum Tension Ring (Integrated into the Dome)

Integrated within the dome structure. Minimizes work on existing tanks but increases dome cost. Requires evaluation of the tank’s top edge.

7. RFQ Preparation Checklist

• Tank drawing or sketch.

• Design conditions

• Type of tension ring

• Shoe support type (sliding, bolting, hinge, advanced bolting)

• Required accessories

• Top angle and wind girder dimensions

• Design standard

• Language and units

8. Installation Assistance (Optional)

Specify if tools, installation supervision, or special equipment are required.

9. Conclusion

Correct definition of loads, shoe type, and tension ring type—especially the carbon steel tension ring—ensures an accurate quotation and optimal tank–dome interaction.