Issuing body
API
Latest edition
7th Edition (2020)
Region
USA, Global
Equipment items
1
Scope
Tube wall thickness calculation for fired heaters operating in the creep range. Identical to ISO 13704.
Key requirements (7)
- Calculation of heater tube thickness in petroleum refineries.
- Two design temperature concepts: elastic design (creep not governing) and rupture design (creep governing).
- Elastic allowable stress: 2/3 yield at design temperature.
- Rupture allowable: based on Larson-Miller parameter, typical 100,000 hr design life.
- Permissible stress = lower of elastic or rupture allowable.
- Tube thickness: t = P·D/(2·σ + P) for straight sections.
- Materials: 5Cr-½Mo, 9Cr-1Mo (T9), 18Cr-8Ni (304/304H), 25Cr-20Ni (310), Alloy 800H — by service severity.
Related standards (1)
Applied to 1 equipment item
Fired Equipment