ASME Section VIII Division 2, Thermal Fatigue Screening

[Phantom9845]

Hello,

I'm hoping someone can help me interpret the limits of an adjacent point is in reference to a flat plate.

Part 5 defines an adjacent point for a flat plat (in Section 5.5.2.3(a)) as any point within the distance "L =3.5a". "a" is then defined in the nomenclature as the "radius of hot spot or heated area within a plate".

So my question is as follows: How is the "hot spot" defined and what criteria do you use to determine its limits?

In looking at Table 5.8, any temperature differential greater than 50°F gets a fatigue screening factor greater than zero . Would it then be safe to assume that a "hot spot" is an area in which the temperature exceeds the mean vessel temperature by more than 50°F?

I believe I have a reasonable interpretation of the code, but was hoping to hear any opinions on where I went wrong or if I am on the right path.

Thanks

 

[TGS4]

Until Division 2 is updated to match API-579-1/ASME FFS-1, I would recommend for you to follow the guidance (and additional details) in 14.4.2.3 of 579-1.

If you have questions after reviewing that paragraph, feel free to return with questions.

Note that the delta T is an instantaneous temperature difference, over any thermal transient, not just "normal" operation.