Dear all,

ASME B31.3 states:

300.1.3 Exclusions. This Code excludes the
following:

(c) tubes, tube headers, crossovers, and manifolds of
fired heaters, which are internal to the heater enclosure

My question is:

Wiche code should I use for the Stress Analysis of piping inside the heater enclosure such as: catalyst tube, inlet and outlet pigtail?

TY.

any comment?

You may consider the provisions of API Std 560 (which now is the identical national adoption of ISO 13705) Petroleum, petrochemical and natural gas industries- Fired heaters for general refinery service.

I mean, is it useful to make a stress analysis of this components (inlet pigtail, catalyst tube, and outlet pigtail) using CAESAR with code compliance B31.3? even if these piping components are not covered by the code?

TY.

any comments will be appreciated.