I was reviewing B31.3 para 302.2.4, which deals with the option to allow a piping system to undergo pressure and/or temperatures variations that are above the design pressure and design temperature. Most of the calculations involved need to be done by the designer using his own set of calculations (see appendix V). In order to allow a piping system to undergo these excursions (and apply appendix V) above the design pressure and/or temperature, there are certain criteria needed to be met. Some of these requirements may not be so straightforward to calculate by hand, and for which AutoPIPE could be of assistance, like
Would this be something that could be achieved by AutoPIPE within it's current version, or would this have to be an enhancement?
Now, when such requirements are met, appendix V can be used, which at it's turn also requires certain stresses to be calculated (e.g. V301.1.(b)). These could also be calculated from AutoPIPE (or extracted from AutoPIPE calculated that are anyhow).
Furthermore, para 302.2.4. refers to para 302.3.6, where Elevated Temperature Fluid Service (short ETFS) is mentioned. When ETFS is applicable, occasional loads may be calculated alternatively.
Would AutoPIPE be able to
If not, is this something that could be logged as an enhancement?
In the meantime, to further reduce the scope of my questions, Ive noticed the ETFS option is available in AutoPIPE, by selecting Use Alt Occ Allow. However, when selecting that option, AutoPIPE applies this requirement at a certain temperature, based on material group (austenitic and non-austenitic). This gives the idea there's no differentation in material grades, e.g. 304L versus 347H or Inconel 800HT;
B31.3 specifies for ETFS:
(c) Elevated Temperature Fluid Service: a fluid service in which the piping metal temperature is sustained equal to or greater than Tcr as defined in Table 302.3.5, General Note (b).
The value for Tcr for is different for most materials and may vary by more than 100 °C for certain austenitic stainless alloys, when using the values from II-D. Better yet, even for certain material grades (like A312 TP316), there are different values for Tcr (in II-D). And for most austenitics, 800F seems like a fairly low value; 950 F seems better.
Does this mean there's a difference between the Code requirements and how AutoPIPE handles Elevated Temperature Fluid Service?
Hi HVN,
The requirements of Para 302.2.4 stated in your query can be dealt with in the following ways:
Regarding the second part of your query about the application of ETFS at a given temperature of 800 °F, I would like to point out that this condition only applies when using the 2008 or older versions of the B31.3 standard. For application in the newer version of the code, please refer to the ‘Alternate Occasional Allowable Stress (ASME B31.3 – 2010)’ help file which states the following:
As of yet Autopipe does not facilitate users in checking whether or not the requirements of appendix V are met. Adding this as an enhancement is under review, and you will be informed as soon as a decision is made.
Regards,
Ameer Abdullah
Answer Verified By: HVN
Thanks Ameer for coming back to this question. I will look into your answer and the options provided.