External Pressure check temperature limitation - Part 5, ASME SEC VIII Div 2

[VeeEng]

Hi All,

While performing external pressure check for SA-387 Gr 11 CL 2 material using protection against buckling per Part 5 of ASME SEC VIII div 2, what is the temperature limitation for time independent properties ? Whether values in Table 4.4.1(below 425 C) to be respected or can we proceed as per table 5A of Sec II part D ( below 500 C) ? I could not find a connection between table 4.4.1 and part 5 .

Thanks in advance !

Regards

VeeEng

 

[NRP99]

VeeEng

Part 4 (Class 1) - Use Table 2A. Then Table 4.4.1 applies.
Part 5 (Class 2) - Use Table 5A.

For Class 2 construction you can either use Part 4 or Part 5 or combination of both.

Class 1. Rules in Part 5 shall not be used in lieu of rules in Part 4.
Class 2. A design-by-analysis in accordance with Part 5 may be used to establish the design thickness and/or configuration (i.e., nozzle reinforcement configuration) in lieu of the design-by-rules in Part 4 for any geometry or loading conditions (see 4.1.5.1). Components of the same pressure vessel may be designed (thickness and configuration) using a combination of Part 4 design‐by‐rules or any of the three methods of Part 5 design‐by‐analysis in 5.2.1.1. Each component shall be evaluated for all of the applicable failure modes in 5.1.1.2 using the methodology of Part 4 or Part 5. If the failure mode is not addressed in Part 4 (e.g., ratcheting), then the analysis shall be in accordance with Part 5. Structural interactions between components shall be considered.

Class 2. The design-by-rule methods of Part 4 shall be applied using the load and load case combinations specified in 4.1.5.3. Alternatively, the design thickness may be established using the design-by-analysis procedures in Part 5, even if this thickness is less than that established using Part 4 design-by-rule methods.

 

[TGS4]

Please stay out of that creep regime for implementing the buckling rules in Part 5. The rules are not applicable to creep buckling.

 

[VeeEng]

Sirs,
Noted your points.
However, my point of concern is..

What is the temperature limit of time-independent stress values for Gr. 11 if I need to demonstrate protection against buckling?

Table 4.4.1 limits is to 425 C
Table 5A limits it to 500 C

I’m clear that if I design per Part 4 then I’m limited by 425 per table 4.4.1

But I’m not clear for Part 5 analysis temperature limit for external pressure and compressive loads.

Regards
VeeEng

 

[NRP99]

VeeEng

That depends on vessel construction - class 1 or class 2 as stated in my earlier post. What's your class of construction? I think that makes it clear.

Please stay out of that creep regime for implementing the buckling rules in Part 5. The rules are not applicable to creep buckling.

My approach as above-If the operating temperature (including excursion events if any) is in creep regime. Then you may refer API 579 assessment for creep buckling.

No need to consider creep buckling if design temperature is in creep and operating temperature is not.

 

[TGS4]

Agreed that creep does not govern the allowable tensile stress in Table 5A (if you have Class 2 construction) until 500°C. However, per Table 4.1 of API 579-1 (Title: Temperature Limit Used to Define the Creep Range), creep starts at 427°C for 1-1/4Cr-1/2Mo materials. Therefore, I would tend to fall back to the limit is Table 4.4.1 for compressive stresses.

I also completely agree with NRP99's comment about using the operating temperature to determine whether or not you are in the creep range.

 

[NRP99]

However, per Table 4.1 of API 579-1 (Title: Temperature Limit Used to Define the Creep Range), creep starts at 427°C for 1-1/4Cr-1/2Mo materials. Therefore, I would tend to fall back to the limit is Table 4.4.1 for compressive stresses.

Ok. Then listing the temperatures for SA 387 Gr 11 Class 2-

ASME Sec II part D, Table 1A - Note T3 Allowable stresses for temperatures of 455°C and above are values obtained from time–dependent properties. (Tensile)
ASME Sec II Part D, Table 5A - Note T7 Allowable stresses for temperatures of 500°C and above are values obtained from time–dependent properties. (tensile)
ASME Sec VIII Div 1, Part 4, Table 4.4.1 Maximum Metal Temperature for Compressive Stress Rules -425deg C (Compressive)
API/ASME FFS 579 - Table 4.1 – Temperature Limit Used To Define The Creep Range -427deg C (Most probably tensile)

Then If I look at the API 579, it directs me to Annex 2D.

10.5.5 Creep Buckling
10.5.5.1 b) 4)-If a numerical analysis is performed to determine the buckling load for a component, all possible buckling mode shapes shall be considered in determining the minimum buckling load for the component (see Annex 2D).

2D.4.1 Assessment Procedure
The assessment procedures for Protection Against Collapse from Buckling shall be in accordance with VIII-2, Part 5, paragraph 5.4 except that the a RSF may be applied for load case combinations as shown in Table 2D.2 in a Type 1 or Type 2 assessment, and that the load case combinations as shown in Table 2D.4 that incorporate a RSF may be used in a Type 3 assessment.

Then If I have to use Sec VIII Div 2 Part-5, am I supposed to use Table 4.4.1? I think no (or....yes if "compressive " stress temperature limitation exists only at Table 4.4.1).

Its clearly confusing to see so many requirements. Perhaps code interpretation exists or may I suggest VeeEng to raise code interpretation?

On side note- best option is avoid MOC that is in creep range at operating temperature. Why to make life of vessel hell when it is already experiencing lot of "stress"?

 

[VeeEng]

Thank You Sirs for your valuable inputs. Discussions were really helpful.

 

[TGS4]

Great suggestion that VeeEng raises a Code Interpretation request. When you do so, please return to this forum with the ASME tracking number provided to you. There are ASME Code Committee members who participate in these discussions are can work to help shepherd these questions through quicker.

 

[VeeEng]

Hi TGS4 and NRP,

I went through the code interpretations and found BPV VIII-2-16-11.

Question: Paragraph 5.1.1.3 states that the design-by-analysis procedures in Part 5 may only be used if the allowable stress from Annex 3-A evaluated at the design temperature is governed by time-independent properties. In order to satisfy 5.1.1.3, is use of the non-italicized allowable stress values (or as defined in the applicable “T” Notes) taken from Section II Part D the only basis for determining when the design temperature is in time-independent range?

Reply: Yes.

From the above interpretation , I guess we can infer that for all procedures in Part 5, the only basis for time independent temperature limit. Please advise.

Regards
VeeEng

 

[TGS4]

I had forgotten about that interpretation. That’s rather definitive. I think you have your answer.

 

[NRP99]

Now we have completed the circle-

Then If I have to use Sec VIII Div 2 Part-5, am I supposed to use Table 4.4.1? I think no (or....yes if "compressive " stress temperature limitation exists only at Table 4.4.1).

Use Table 5A.

 

[VeeEng]

Hi TGS4 and NRP,

Further to the above discussions, for Canadian registration , will Cl 7.1.5 of CSA B51-19 part 1 restricts protection against buckling check (part 5 of Sec VIII Div 2) at 495C for Gr 11 tubes ?

Regards
VeeEng

 

[TGS4]

VeeEng - I wouldn't necessarily interpret it that way. Best to check with the jurisdiction that you are submitting to. Which one would that be?

 

[VeeEng]

Hi TGS4,
Thank you for the reply.
The equipment is to be installed at Alberta.

Regards
VeeEng

 

[david339933]

You better check with ABSA or you may be in for a big surprise.

 

[IdanPV]

Hi,

If Part 5 DBA is in use - you shall follow the rules of AB-520.
I suggest you to hire an engineering firm in Canada with experience regarding that issue.

 

[VeeEng]

Hi ,
An update !
ABSA confirmed that Part 5 can be used for the above scenario where there are no provisions in Part 4 of the code.

Thank you for all your valuable replies!

Regards
VeeEng