Category
Heat Transfer Equipment
Subcategory
Heat Exchanger
Applicable standards
3
Issuing bodies
3
Description
Double-pipe or multi-tube hairpin exchanger for small-duty, high-fouling or high-pressure service.
Applicable Standards (3)
API — 1 standard
API 660
Shell-and-Tube Heat Exchangers
Design, materials, fabrication, inspection and testing of shell-and-tube heat exchangers. Identical to ISO 16812.
Key requirements (8)
- Shell-and-tube heat exchangers for petroleum, petrochemical, natural gas.
- Companion to TEMA — provides additional engineering / procurement requirements.
- Min tube wall: 2.1 mm (0.083") CS, 1.65 mm (0.065") SS — 25 mm OD typical.
- Tube-to-tubesheet joint: strength-welded + light-rolled OR full-strength expanded; expansion ≥ 2× tube wall.
- Shellside velocity: 0.6–1.5 m/s liquid; tubeside 1–3 m/s typical.
- Hydrotest per ASME VIII Div 1 (1.3 × MAWP).
- Vibration analysis (TEMA / HEDH): natural frequency, fluid-elastic instability, vortex shedding.
- Differential thermal expansion handled by floating head, U-tube, or expansion bellows.
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.
TEMA — 1 standard
TEMA (R, C, B)
Standards of the Tubular Exchanger Manufacturers Association
Mechanical standards for shell-and-tube heat exchangers — Class R (refinery), C (commercial), B (chemical).
Key requirements (9)
- Mechanical standards for shell-and-tube exchangers — Class R (refinery/severe), C (commercial), B (chemical).
- Class R: heaviest construction — petroleum/petrochemical; 19 mm tube, 38 mm pitch typical.
- Class C: lightest — moderate service; 16 mm tube, 32 mm pitch typical.
- Class B: chemical process; intermediate.
- Type designation 3-letter (e.g. AES = removable channel, single-pass shell, floating head split-ring).
- Front end: A (channel/bonnet), B (bonnet integral), C (channel integral with TS), D (high-pressure closure).
- Shell types: E (1-pass), F (2-pass with longitudinal baffle), G (split-flow), H (double split-flow), J (divided flow), K (kettle), X (cross flow).
- Rear end: L–M (fixed TS), N (fixed integral channel), P–S–T (floating heads), U (U-tube), W (externally sealed floating).
- Standard impingement plate above 750 mass-velocity index ρv² for liquid shellside.