Category
Heat Transfer Equipment
Subcategory
Heat Exchanger
Applicable standards
3
Issuing bodies
3
Description
Brazed aluminum plate-fin exchanger for cryogenic and LNG cold-box service.
Applicable Standards (3)
ASME — 1 standard
ASME BPVC Sec VIII Div 1
Rules for Construction of Pressure Vessels
Mandatory rules for design, fabrication, inspection, testing and certification of pressure vessels operating above 15 psig (~1 barg).
Key requirements (12)
- Applies to vessels with internal pressure > 15 psig (1.03 barg) up to ~3000 psi (Div 1 sweet spot).
- Joint efficiency E: 1.0 (full radiography), 0.85 (spot RT), 0.70 (no RT) for Type 1 butt joints.
- Shell thickness: t = P·R/(S·E – 0.6·P) for circumferential stress (UG-27).
- Head thickness: t = P·D/(2·S·E – 0.2·P) for 2:1 ellipsoidal heads (UG-32).
- Hydrostatic test pressure: 1.3 × MAWP × (S_test/S_design) — UG-99.
- Pneumatic test (when hydro impractical): 1.1 × MAWP — UG-100.
- Corrosion allowance is added to calculated thickness (not included in S formula).
- MDMT and impact testing per UCS-66 / Figure UCS-66; below the curve, Charpy V-notch impacts are required.
- PWHT thresholds per UCS-56 — generally required above 19 mm thickness for P-No. 1 carbon steels.
- Nozzle reinforcement: area replacement method (UG-37) within reinforcement zone.
- Maximum allowable stress S: from ASME II Part D, Table 1A/1B/3 — temperature dependent.
- Flanges per ASME VIII-1 Appendix 2 (or B16.5 for standard sizes).
Note: Most widely used pressure vessel code worldwide.
ALPEMA — 1 standard
ALPEMA Standard
The Standards of the Brazed Aluminium Plate-Fin Heat Exchanger Manufacturers' Association
Brazed aluminum plate-fin heat exchangers (BAHX) for cryogenic and air-separation duty.
Key requirements (8)
- Brazed Aluminium Plate-Fin Heat Exchanger (BAHX) standard.
- Aluminum 3003 / 3004 alloy core, vacuum-brazed at ~600 °C.
- Multi-stream (often 5–10 streams in one core) — enables LNG cold-box duty.
- Operating range: cryogenic (–269 °C) to ~65 °C; pressure typically up to 100 barg.
- Hydrotest: 1.43 × MAWP.
- Pressure-differential limit between adjacent streams (typical 30–60 bar) — drives design.
- Particulate filtration ≤ 50 µm to protect fin/perforated plate fouling.
- Mercury removal upstream mandatory (Hg attacks aluminum).
EN/CEN — 1 standard
EN 13458 (series)
Cryogenic vessels — Static vacuum insulated vessels
Vacuum-insulated static vessels for cryogenic gases (LIN, LOX, LAR, LH2, LHe).