API 650 Tank Designer

Vertical cylindrical storage tank design aid (shell, bottom, roof, wind)

Metric US Customary

Design Inputs

General

Tank Diameter (D)

Tank Height (H)

Specific Gravity (G)

Geometry Import (DXF / SVG)

Wind-girder 2nd moment I (mm⁴)

Soil modulus kₛ (kN/m³)

Allowable bearing (kPa)

Ringwall width b (m)

Shell

Design Method One-Foot Method Variable-Point (VDP)

Shell Material

Allowable Stress S_d

Weld Joint Efficiency (E)

Corrosion Allowance (CA)

Number of Shell Courses

Course Heights (top→bottom), comma separated

Cone Roof

Roof Type Self-supporting Cone Self-supporting Dome Supported Cone

Cone Roof Slope Angle (θ) °

Roof Live/Snow Load (q) kPa

Internal Pressure (P) kPa

Wind Girder

Design Wind Speed (V, 3-s gust)

Girder Allowable Stress

Top course t_top (mm)

Vacuum / External (Appendix V)

Vacuum Level kPa

Axisymmetric buckling controls — full ASME ring design required.

Seismic (Appendix E)

Seismic Coefficient (C_s)

Simplified equivalent-static. Verify with API 650 Appendix E and PE review.

Anchorage & Stability

Number of Anchor Bolts

Anchor Bolt Size

Settlement (API 653 Annex B)

Adjacent Settlement Δ (≤3 m) mm

Edge Differential Settlement mm

Center Dish Settlement mm

In-Service Assessment (API 653)

As-built Min Thickness t₀ mm

Measured Min Thickness tₙ mm

Years in Service yr

Remaining Life / Inspection (API 653 §4.4)

As-built Min Thickness t₀ mm

Measured Min Thickness tₙ mm

Years in Service yr

API 653 §4.4...

Low-Temperature / MDMT

Design Metal Temp T_min °C

Heat Treatment

Impact Test Performed

Venting (API 2000)

Max Fill Rate (pump-in) m³/h

Max Empty Rate (pump-out) m³/h

Insulated Tank

Fire Exposure Case

Conservation Vent (PVRV) Fitted

Nozzle Reinforcement (App. P)

Shell diameter (m) m

Shell course t (mm) mm

Design pressure (kPa) kPa

Shell S (MPa) MPa

Nozzle S (MPa) MPa

Joint eff. E

Nozzle wall t (mm) mm

Nozzle OD (mm) mm

Corr. allowance (mm) mm

API 620 Low-Pressure Tank

Internal gas pressure (kPa) kPa

Annex R material

EN 14015 (European)

Yield fy (MPa) MPa

Joint eff. φ

Force coeff. Cf

Safety factor

EN 14015 external stability...

API 653 In-Service (extended)

Min measured shell (mm) mm

Hydrotest fill (m) m

Steel category

Max plate (mm) mm

Service temp (°C) °C

Hydrotest < 0 °C

Min existing bottom (mm) mm

API 653 hydrotest...

Nozzle Flange (ASME B16.5)

Design pressure (bar) bar

Design temp (°C) °C

ASME B16.5 Group 1.1...

Bolted Flange (ASME VIII-1 App.2)

NPS

Class

Gasket type

Design pressure (MPa) MPa

Bolt temp (°C) °C

Bolt allow. (MPa) MPa

Gasket dia G (mm) mm

Eff. width b (mm) mm

ASME VIII-1 App.2 m/y...

Support (legs / skirt)

Legs

Leg OD (mm) mm

Leg wall (mm) mm

Leg length (m) m

Yield (MPa) MPa

Elevated-tank support...

Foundation / Settlement

Footing width B (m) m

Soil allow. q (kPa) kPa

Soil modulus E (kPa) kPa

Poisson ν

Single-leg footing...

API 653 Repair / Welding

Current min t (mm) mm

Required t (mm) mm

Min plate t (mm) mm

Defect depth (%) %

Defect dia (m) m

Location

3D View

Azimuth (°)

Elevation (°)

Fitness-For-Service (API 579 L1)

Loss type

Nominal thk (mm)

Remaining thk (mm)

Design P (MPa)

Inside radius (mm)

Thin length L (mm)

Thin width W (mm)

LTA dia d (mm)

Future CA (mm)

Corrosion (mm/yr)

Fitness-For-Service (API 579 L2/L3)

Level

Uniform corroded t_c (mm)

Long. extent s (mm)

Grid step (mm)

Thickness grid (rows, csv)

Re-Rating (API 653)

New fill height (m)

Existing min t (mm)

Nozzle Re-Rating (App P)

New design P (bar)

Nozzle OD (mm)

Nozzle t (mm)

Shell t (mm)

Nozzle S (MPa)

Shell S (MPa)

Nozzle CA (mm)

Added reinf (mm²)

Roof Structure

Dead load (kPa)

Live load (kPa)

No. columns

Girder span (m)

Rafter span (m)

Column OD (mm)

Column t (mm)

Column len (m)

Steel Sy (MPa)

Ringwall Foundation (API 650 Annex B)

Ringwall width (m)

Ringwall height (m)

Soil bearing (kPa)

Conc. fc (MPa)

Diff. settlement (mm)

Ring height h_ring (m)

Floating Roof (API 650 App C/D)

Deck type

Deck thk (mm)

Pontoon area (m²)

Pontoon draft (m)

Design rain (mm)

Deck slope 1:x

In-Service Shell Assessment (API 653)

Measured course thickness (mm, bottom→top, CSV)

Corrosion rate (mm/yr)

Design Summary

Design Inputs

Shell

Course

Required

Minimum

Used

PASS

Shell required thickness vs height

Bottom & Annular

Cone Roof

Internal Pressure (Appendix F)

Wind Girder

Intermediate Wind Girders

Seismic (Appendix E)

Anchorage & Stability

Vacuum / External (Appendix V)

Capacity & Volume

Weight Estimate

Settlement (API 653 Annex B)

In-Service Assessment (API 653)

Remaining Life / Inspection (API 653 §4.4)

Low-Temperature / MDMT

Venting (API 2000)

Nozzle Reinforcement (App. P)

API 620 Low-Pressure Tank

EN 14015 (European)

EN 14015 Stability (wind)

API 653 Repair / Welding

API 653 In-Service (extended)

Nozzle Flange (ASME B16.5)

Bolted Flange (ASME VIII-1 App.2)

Support (legs / skirt)

Foundation / Settlement

Fitness-For-Service (API 579 L1)

Fitness-For-Service (API 579 L2/L3)

Re-Rating (API 653)

Nozzle Re-Rating (App P)

Roof Structure

Ringwall Foundation (API 650 Annex B)

Floating Roof (API 650 App C/D)

Material Take-Off (BOM)

In-Service Shell Assessment (API 653)

Course	Required (mm)	Min (mm)	Measured (mm)	Remaining (mm)	Margin (mm)	Life (yr)	Verdict

FEA Triage (stub)

Shell Stability FEA

Foundation FEA (Winkler)

Tank Schematic

3D View

Isometric preview (canvas, no external library)

Formula Reference (API 650)