Case Study
API 650 Storage Tank Engineering — Design & Detail Drawings
Storage Tank EngineeringConfidential Details Removed
Problem / Requirement
A refinery expansion required a new fixed-roof atmospheric storage tank for hydrocarbon service at elevated operating temperatures. The existing site drawings were incomplete, and the client needed a full design package — from process datasheet through to fabrication-ready drawings — compliant with the latest edition of API 650, suitable for third-party review and procurement.
Engineering Scope
Tank sizing and shell course thickness design per API 650 variable-design-point method
Fixed cone roof design including rafter and girder sizing under wind and snow load
Annular plate and bottom plate design with corrosion allowance and settlement check
Nozzle schedule preparation, reinforcement pad sizing and flange rating selection per ASME B16.5
Wind load stability and shell buckling check per API 650 Appendix V
Seismic design and freeboard check per API 650 Appendix E for site-specific spectral parameters
Civil foundation load summary (operating, empty, hydrotest) for structural engineer
Review of vendor fabrication drawings and resolution of technical queries (TQs)
Deliverables
API 650 Design Calculation ReportTank Shell Course Thickness ScheduleGeneral Arrangement (GA) Drawing — Plan & ElevationNozzle and Manway Schedule DrawingRoof Framing Plan and Rafter Detail DrawingBottom Annular Plate Layout DrawingFoundation Load Summary Data SheetFabrication Drawing Review Comment Register
Client Value Delivered
Complete, stamp-ready design package delivered within four weeks, enabling fast-track procurement
Shell thickness optimisation reduced total plate weight by approximately 8% versus uniform-thickness approach
Seismic freeboard check confirmed tank height was adequate, avoiding costly tank diameter increase
Single consolidated comment register eliminated back-and-forth with the fabricator and cut TQ cycle time
Foundation load summary provided in a format directly usable by the civil team, removing coordination delays
Standards Referenced
API 650 (12th Ed.)API 650 Annex E (Seismic)API 650 Annex V (Wind)ASME B16.5ASME B16.47ASME B16.25ASCE 7
Software Used
TANK (Intergraph)AutoCAD 2024Microsoft Excel (Calculation Sheets)COMPRESS (Codeware)
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