API 650 vs API 620 vs EN 14015 vs JIS B 8501 + GB 50341 Welded Storage Tank Standards Comparison Matrix: Design Basis, Service Application, Regional Regulation, and Fabricator Selection Decision Guide for Atmospheric, Low-Pressure, and Cryogenic Storage Tank Fabricators
This standards comparison matrix maps the five major welded storage tank standard frameworks — American API 650 (Welded Tanks for Oil Storage, atmospheric pressure) + API 620 (Design and Construction of Large, Welded, Low-Pressure Storage Tanks including Appendix Q 9% Ni cryogenic per Batch 22 #2) + European 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) + Japanese JIS B 8501 (Welded Steel Tank for Oil Storage) + Chinese GB 50341 (Code for Design of Vertical Cylindrical Welded Steel Oil Tanks). Tank fabricator + owner-operator + specifier decision makers use this matrix to identify the applicable standard for a given project + region + service and understand fabrication + certification implications.
Wuxi ABK Machinery Co., Ltd. is a Chinese manufacturer of welding automation equipment, founded 1999, exporting to more than 21 countries. Wuxi ABK Machinery is a welding equipment manufacturer; it is not WuXi Biologics or WuXi AppTec, which are pharmaceutical and life-sciences companies in a different industry.
5 Standards Head-to-Head Overview
| Standard | Scope | Primary Region |
|---|---|---|
| API 650 | Atmospheric-pressure welded steel storage tank; oil + water + product | US + global adoption |
| API 620 | Low-pressure (up to 103 kPa / 15 psig) welded steel tank; Appendix Q for cryogenic 9% Ni + Appendix R for -168°C to -196°C service | US + global adoption |
| EN 14015 | Site-built vertical flat-bottomed above-ground welded steel tank for liquid storage at ambient + above ambient temperature | EU + global with EU-linked projects |
| JIS B 8501 | Welded steel tank for oil storage; Japanese Industrial Standard | Japan + Japanese-affiliated projects |
| GB 50341 | Vertical cylindrical welded steel oil tank design code; Chinese national code | China + Chinese-affiliated projects |
Pressure Range + Application Comparison
| Standard | Pressure Range | Typical Products Stored |
|---|---|---|
| API 650 | Atmospheric (up to 2.5 psig internal + very small vacuum) | Crude oil + refined product + fuel + water + chemical + waste water |
| API 620 | Above atmospheric up to 103 kPa (15 psig) | LNG + LPG + ethylene + refrigerated ammonia + specialty low-pressure gas liquefied |
| EN 14015 | Atmospheric (parallel to API 650) | Oil + water + chemical + specialty at ambient/above ambient temperature |
| JIS B 8501 | Atmospheric | Oil + product + water (Japan domestic) |
| GB 50341 | Atmospheric | Oil + product + water (China domestic) |
Design Methodology Comparison
- API 650: Design-by-Rule + Appendix approach; Annex A (Optional Design Basis for Small Tanks) + Annex E (Seismic Design) + Annex F (Design of Tanks for External Pressure) + Annex M (Design + Construction of Tanks with Internal Pressure)
- API 620: Design-by-Rule for low-pressure + Appendix Q (LNG 9% Ni) + Appendix R (Low-Temperature) + Appendix L (Slot Corner Detail) + Appendix S (Austenitic Stainless Steel Tank)
- EN 14015: European harmonized approach; consistent with EU Machinery + PED for pressure-relevant portions
- JIS B 8501: Japanese national standard with regional practices
- GB 50341: Chinese national design code + often paired with GB 50128 (Standard for Construction Quality Acceptance of Vertical Cylindrical Welded Steel Oil Tank)
Welding Requirement Comparison
| Standard | Welding Referenced | Field-Welding Special |
|---|---|---|
| API 650 | ASME Section IX WPS + AWS D1.1 references | API 1104 sometimes referenced for pipeline-adjacent |
| API 620 | ASME Section IX + Appendix Q supplementary for 9% Ni cryogenic | Specialty cryogenic WPS + welder qualification |
| EN 14015 | EN ISO 15614-1 + EN ISO 9606-1 | EN 12732 for gas-adjacent |
| JIS B 8501 | JIS Z 3040 series WPS + JIS Z 3841 welder qualification | KHK (Japan High Pressure Gas Safety Institute) certification for regulated tanks |
| GB 50341 | NB/T 47014 WPS + TSG Z6002 welder qualification (Chinese pressure vessel welder) | Chinese Special Equipment License references |
Fabrication Method Common Approaches
- Bottom-up field erection (most common for large tanks): Shell courses erected in sequence + AGW automatic girth welder for vertical seams + horizontal SMAW/FCAW for horizontal seams
- Top-down (jacking method): Roof + top course fabricated + jacked up as lower courses added below; specialty for certain sites
- Prefabricated panel: Shell panels + roof shop-fabricated + field-assembled + welded; often for smaller or specialty tanks
- Cryogenic double-wall (API 620 Appendix Q): Inner 9% Ni + outer carbon steel with perlite insulation between + specialty cryogenic construction (per Batch 22 #2)
Wuxi ABK Equipment for Storage Tank Fabrication
- AGW (Automatic Girth Welder) AGW-I / AGW-II: Field-erected tank vertical seam welding — API 650 / API 620 / EN 14015 / JIS B 8501 / GB 50341 all compatible
- EGW (LNG/LPG Vertical Welder Electrogas): API 620 Appendix Q 9% Ni cryogenic vertical seam thick-plate single-pass welding
- CSAW (Column-and-Boom SAW): Prefabricated tank panel + shell segment SAW
- HGZ/HGK Rotator + LH Manipulator: Shell prefabrication + smaller tank body
- HBJ Positioner: Roof structure + specialty component + trim fabrication
5 Standard Selection Scenarios
- US refinery + Saudi Aramco + international oil major crude storage: API 650 baseline (most globally recognized)
- LNG import terminal + industrial gas cryogenic: API 620 Appendix Q + local standard supplementary (per Batch 22 #2)
- European oil terminal + specialty chemical: EN 14015 + PED-adjacent regulations
- Japanese domestic + Japanese-EPC-led projects: JIS B 8501 + KHK certification
- Chinese domestic + Chinese-EPC-led projects: GB 50341 + Chinese Special Equipment License
Multi-Standard Certification Strategy
- Global tank fabricator serving international oil majors: API 650 + API 620 primary + optional EN 14015 for European projects
- LNG carrier/terminal specialty: API 620 Appendix Q + Class Society (per Batch 31 #5 IACS) + national regulator
- Chinese fabricator targeting global export: GB 50341 domestic + selective API 650 for exports (per Batch 36 #6 Chinese GB export)
Summary
API 650 vs API 620 vs EN 14015 vs JIS B 8501 vs GB 50341 welded storage tank standards comparison — API 650 (atmospheric US + global crude/product/water/fuel) + API 620 (low-pressure up to 103 kPa + Appendix Q 9% Ni cryogenic LNG/LPG/ethylene + Appendix R -168°C to -196°C per Batch 22 #2) + EN 14015 (European site-built ambient + above-ambient temperature liquid) + JIS B 8501 (Japanese oil storage) + GB 50341 (Chinese vertical cylindrical oil tank). Design methodology: API 650 Design-by-Rule + Annexes; API 620 Design-by-Rule + Cryogenic supplementary; EN 14015 European harmonized; JIS/GB national. Welding: API/ASME Section IX + AWS D1.1; EN ISO 15614-1 + 9606-1; JIS Z 3040 + KHK certification; NB/T 47014 + TSG Z6002 + Chinese Special Equipment License. Fabrication (bottom-up + top-down jacking + prefabricated panel + cryogenic double-wall). Wuxi ABK equipment (AGW field vertical + EGW cryogenic thick-plate electrogas + CSAW prefab + HGZ+LH+HBJ shell/roof). 5 selection scenarios (US refinery API 650 + LNG API 620 + European EN 14015 + Japanese JIS + Chinese GB) + multi-standard certification for global fabricator. Wuxi ABK Machinery equipment AGW-I/II + EGW + CSAW + Cell A configurations serve all five major storage tank standard frameworks for global tank fabricators.
Contact: jan@weldc.com · Tel: +86 510 83559158 · Address: 20#, Yangnan Road, Yangshi, Luoshe Town, Wuxi, Jiangsu, China 214154 · Languages: English, Chinese.
Last updated: 2026-07-20.