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OUR SERVICES

 

  • Design Calculations Preparation

  • GA drawings preparation

  • Fabrication drawings preparation 

  • Tank Form & Tank Terminal design

  • Vendor documents review

  • Cost Estimation for tenders

  • FEED front end design engineering

  • Basic design engineering

  • Tender documentation preparation

  • Tank selection and sizing

  • Material selection 

  • P & ID drawing preparation

  • Storage tank pumps selection and sizing

  • Tanks piping design and sizing

  • Overall plant layout preparation

  • Plate cutting drawings preperation

  • Tank design standards.

  • Maintenance manual preparation

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Floating roof storage tank design,
Floating roof storage tank design,
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API 650 refers to a standard published by the American Petroleum Institute (API)

API 650 refers to a standard published by the American Petroleum Institute (API) for the design, construction, and inspection of welded storage tanks used in the petroleum and chemical industries. These tanks are typically aboveground and cylindrical, with fixed roofs, floating roofs, or other types of covers.

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Floating Roof Tanks (FRTs) – API 650 Overview

Floating roof tanks are storage tanks with a roof that floats directly on the surface of the stored liquid, reducing vapor space and minimizing evaporation losses. They are widely used in storing volatile liquids such as crude oil, gasoline, and other petroleum products.

API 650 covers both external and internal floating roof tanks through different sections and appendices.

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External Floating Roof Tank (EFRT)

✅ Design Highlights

  • Open-top with a floating deck

  • Typically includes:

    • Pontoon-type or double-deck floating roof

    • Roof seals (primary and secondary) to close the gap between the roof and shell

    • Drainage system for rainwater

    • Guides and anti-rotation devices

  • Designed to reduce VOC emissions and comply with environmental regulations

📏 Considerations

  • Roof type: Pontoon or double-deck

  • Shell design: Includes wind and seismic loads (API 650, Appendix F & E)

  • Drainage: Flexible hose or articulated drain system

  • Accessories: Roof legs, gauge poles, shunts (for lightning protection)

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Internal Floating Roof Tank (IFRT)

✅ Design Highlights

  • Has a fixed roof (cone or dome type)

  • Floating deck is inside the tank

  • Used where external floating roofs are not suitable (weather conditions, contamination, emissions regulations)

📚 API 650 Reference: Appendix H

Roof Types in IFRTs:

  • Full contact (aluminum honeycomb, foam-filled)

  • Pontoon type

  • Hybrid types

📏 Design Elements

  • Fixed roof: Designed as per API 650 (e.g., cone or dome)

  • Internal floating roof: As per Appendix H

  • Sealing system: Primary and optionally secondary seals

  • Ventilation: Required to prevent pressure build-up

  • Access and inspection: Hatches, manways, gauge hatches

BS EN 14015. This is the British and European standard

BS EN 14015: Specification for the design and manufacture of site-built, vertical, cylindrical, flat-bottomed, above-ground, welded steel tanks for the storage of liquids at ambient temperature and above

📌 Key Features

FeatureDescription

📅 First Published2004 (current version may be updated – let me know if you want latest via web)

🌍 RegionUK & Europe (based on EN standards)

🏗️ ApplicationSimilar to API 650 — for atmospheric or low-pressure liquid storage

⚙️ Tank TypeCylindrical, vertical, welded, above-ground, flat-bottomed tanks

🌡️ TemperatureAmbient to slightly elevated temps

🔧 Key Design Topics

1. Materials

  • Includes both carbon steel and stainless steel

  • More aligned with European steel grades (e.g., S235, S355)

2. Design Loads

  • Wind, snow, seismic, and internal pressures

  • Seismic per Eurocode 8

  • Wind per EN 1991-1-4

3. Tank Bottom & Shell Design

  • Includes guidance on annular plates, corrosion allowances, etc.

  • Bottom can be single plate or annular ring-based depending on diameter

4. Welding and NDT

  • Strict welding procedures

  • Requires Welding Procedure Specification (WPS), PQRs, and welder qualifications

  • NDT: Radiographic, ultrasonic, magnetic particle, and dye penetrant testing as applicable

5. Inspection and Testing

  • Hydrostatic testing required

  • Includes leak testing of bottom plates

  • Visual and dimensional inspections

🇯🇵 Storage Tank Design Standards in Japan

🏗️ Primary Japanese Standard:

🔹 JIS B 8501 – "Welded Steel Tanks for Oil Storage"

This is the closest equivalent to API 650 in Japan.

📌 Key Features of JIS B 8501

Feature Details

📘 Title Welded Steel Tanks for Oil Storage

🏗️ Type Field-erected, vertical, cylindrical, flat-bottomed steel tanks

🌡️ Temperature Ambient or slightly elevated

📏 Pressure Low-pressure, atmospheric tanks

🧯 Applications Crude oil, petroleum products, chemicals

🔧 Design Elements in JIS B 8501

  1. Tank Shell & Bottom

    • Design stresses and allowable stress similar to API 650

    • Plate thickness, welding joints, corrosion allowance

  2. Seismic Design

    • Japan is highly seismic, so this is critical

    • Earthquake design must follow Japan’s Building Standards Law and Notification No. 593 (Ministry of Construction)

  3. Wind Loads

    • Based on Japan Meteorological Agency data

    • Specific formulas for design wind speed & pressures

  4. Materials

    • Japanese steel grades (e.g., SS400, SM490, similar to ASTM A36 or A516)

    • Material testing & certification required

  5. Roof Types

    • Cone, dome, and floating roofs are supported

    • Design of internal and external floating roofs follows similar logic to API 650, but with Japanese safety codes

  6. Welding & NDT

    • Detailed requirements for welding procedures and testing

    • Radiographic testing, ultrasonic testing, visual inspections

  7. Testing & Inspection

    • Hydrostatic testing is mandatory

    • Includes leak testing of bottom plates

    • Seismic safety inspections may be required post-installation

​

Japanese Industrial Standards (JIS).

Storage Tank Design Standards – China

he main standard for aboveground welded steel tanks in China is:

🔹 GB 50128 – "Code for Construction and Acceptance of Vertical Cylindrical Welded Steel Oil Tanks"

This standard is often used alongside GB 50341 – Code for Design of Vertical Cylindrical Welded Steel Oil Tanks.

These two together cover the design, fabrication, construction, inspection, and testing of oil storage tanks, much like API 650 or BS EN 14015.

🏗️ Key Chinese Standards for Storage Tanks

Standard Title Description

GB 50341Design Code for Vertical Cylindrical Welded Steel Oil Tanks Main design standard (similar to API 650)

GB 50128Code for Construction and Acceptance Covers fabrication, welding, inspection, and testing

GB 50009Load Code for the Design of Building Structures Wind and snow load

GB 50011Code for Seismic Design of Buildings Seismic design (very important in high-risk areas)

GB 12348Emission Standard for Noise at Boundary of Industrial Enterprises May be referenced for operational compliance

HG/T 20570.1~3Floating Roof Tank Accessories Specifics on floating roof seals, vents, etc. (from chemical industry standards)

🔧 Design Scope of GB 50341

  • Vertical, cylindrical, aboveground, flat-bottomed, welded steel tanks

  • Diameter range: Generally from 5 meters to over 100 meters

  • Fluid: Oil and oil products (can be extended to chemicals with similar properties)

  • Temperature: Ambient to mildly elevated

  • Pressure: Atmospheric or very low pressure

🛢️ Floating Roof Tank Design (Internal & External)

Chinese standards recognize both internal and external floating roof tanks, but like BS EN 14015, they're less prescriptive than API 650.

🔄 Floating Roof Design Coverage (GB Standards)

Roof Type Included in GB? Notes

External Floating Roof (EFR)✅ Yes Common in large oil depots

Internal Floating Roof (IFR)✅ Yes Increasingly used for emission control

Fixed Roof✅ Yes Cone or dome style, often with IFR below

👇 Design Based on:

  • HG/T 20570 (Part 1-3) – Chemical industry standard, used for:

    • Floating roof accessories (vents, manways, seals)

    • Pontoon vs full-contact IFRs

  • Enterprise standards or project-specific specs often supplement with API 650 Appendix H principles

🧪 Construction & Testing (GB 50128)

  • Hydrostatic testing

  • Radiographic, ultrasonic, and magnetic particle testing for welds

  • Dimensional tolerance checks

  • Foundation settlement checks

  • Welding qualification procedures per GB/T 3323 or GB/T 11345

⚖️

Wisdom is one of the leading design Service provider for oil & Gas, Petrochemical & process  Industries

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GLOBAL PRESENCE

If you’re planning a new facility or upgrading existing infrastructure, Wisdom Design Consultancy is here to provide cutting-edge design services for your Oil storage tank systems.

With over 22 years of specialized experience in Oil storage tank design,

 

Wisdom Design Consultancy is a trusted name in the industry for delivering high-quality, efficient, and code-compliant solutions tailored to your project needs

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  • 22+ Years of Expertise in Oil Tank Design

  • One-Point Contact for the Entire Project.

  • All engineers and draftsmen on our team have over 15 years of experience in oil tanks design

  • Every design document is thoroughly reviewed and approved by a Senior Design Manager to ensure technical accuracy and quality before delivery.

  • We strictly follow agreed schedules, ensuring on-time delivery without compromising on quality.

  • Compliance with International Codes & Standards, API 650, ASME, EN, ISO, and other applicable global standards.

  • From concept to commissioning, we ensure complete coordination with the client, consultants, and stakeholders at every stage

  • Our solutions strike the right balance between cost-efficiency and safety, without compromising long-term reliability

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(HFO, LFO, FURNACE OIL, CRUDE OIL)

(Vegetable oil, Edible oil, Canola Oil, Soybean Oil:, Coconut Oil: Peanut Oil )

          OIL- STORAGE TANK DESIGN- CONSULTANCY SERVICES

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