# Design basis · TK-101

PRELIMINARY – pre-design, illustrative and not for construction. Not engineered, not fabrication-ready. Code clauses cited, not claimed; unconfirmed until a named engineer confirms them.

| Item | Value | Source |
| --- | --- | --- |
| Medium | Filtrate (water-like) | customer |
| Density | 1010 kg/m³ | customer |
| Diameter × shell height | 12 m × 12 m | engineer |
| Freeboard | 0.6 m | assumed |
| Nominal / working volume | 1289.3 m³ / 1255.4 m³ | engineer |
| Design / operating temperature | 80 °C / 70 °C | customer |
| Design pressure / vacuum | 5 mbar / 2.5 mbar | assumed |
| Material | Carbon steel S355 (EN 10025-2) | customer |
| Corrosion allowance | 1.5 mm | customer |
| Code basis | API 650 (cited, not claimed) | assumed |
| Roof | Cone, 10° | assumed |
| Insulation / agitator / heating | 0 mm / no / no | assumed |
| Design life | 25 years | assumed |
| Fill / empty rate | 300 / 300 m³/h | assumed |
| Terrain category / vb,0 | II / 21 m/s | assumed |
| Ground snow load sk | 2.5 kN/m² | assumed |
| Seismic design required | no | assumed |

## Not confirmed

- API 650 5.6.3.2 one-foot method: td = 4.9 D (H − 0.3) G / Sd + CA and tt = 4.9 D (H − 0.3) / St (SI).
- API 650 5.6.2.1 allowable stresses for carbon steel: Sd = min(2/3 Fy, 2/5 Ft), St = min(3/4 Fy, 3/7 Ft), applied here to EN plate grades.
- API 650 5.6.1.1 minimum shell thickness by diameter: 5, 6, 8 and 10 mm below 15, 36, 60 m and above.
- API 650 5.4.1 minimum bottom plate 6 mm excluding corrosion allowance.
- API 650 5.10.5.1 self-supporting cone roof t = D / (4.8 sin θ) · √(T / 2.2), 5 to 13 mm, slope 9.5° to 37°; 5.10.6.1 dome t = rr / 2.4 · √(T / 2.2); used for both code bases.
- API 650 5.10.2.6 frangible roof-to-shell joint conditions, reduced here to diameter ≥ 15 m and slope ≤ 9.5°.
- API 650 5.9.7.1 maximum unstiffened height H1 = 9.47 t √((t/D)³) (190/V)² with the transformed shell (5.9.7.2); vacuum is not added.
- API 650 5.11.2 unanchored criterion 0.6 Mw + MPi < MDL / 1.5 + MDLR; the liquid-weight criterion is not assessed.
- API 650 5.12 anchor spacing at most 3 m and minimum bolt diameter 25 mm (excluding corrosion allowance).
- EN 14015 9.2.2 shell thickness e = D / (20 S) · [98 W (H − 0.3) + p] + c, test e = D / (20 St) · [98 (H − 0.3) + p]; the test pressure is taken as the design pressure.
- Roof load: roof live load 1.0 kPa or 0.8 sk, whichever is larger, plus 0.4 × vacuum, plus the plate weight and insulation at an assumed 150 kg/m³.
- Wind force coefficient cf 0.8 on the projected area, with cs·cd 1.0, at the peak velocity pressure at the top of the shell.

## Excluded

- Shell, bottom and roof thicknesses are preliminary one-foot sizing; the variable-design-point method, annular plate, shell-to-bottom joint and nozzle reinforcement are not assessed.
- Thermal and fire-case venting, seismic design, the liquid-weight anchorage criterion, foundation settlement effects on the shell, and fatigue are not assessed.
- Stair, ladder, platform, wind-girder and anchor steel is laid out, not sized.
- Toughness at the minimum design metal temperature, welding, inspection and testing are not addressed.