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Thanks guys. Yes, two tanks might be a better option under the limit. However, my point here is about the limit set in the API 650, is it a strength issue or toughness concern? Any insights?

Yes, it is. For the given pump suction head and working capacity, the tank has been sized to 34m Dia X 55m H, with the high S.G and corrosion allowance, the wall thickness at the bottom course would be 1.96". Considering the small ratio of D/H, the variable-Design-Point method would not give a...

Considering the low design metal temperature and cost, CSA G40.21 Grade 350 WT has been specified. ALso the allowable stress has been elevated according to section 5.6.2.1 and 5.6.2.2. That is why i am questioning the limit ... Thanks.

Recently when sizing a storage tank, found that the required thickness will be 51mm (2"), over the limit 45mm (1-3/4") thick as set in section 4.2.1.4 of API 650. The question is whether the maximum plate thickness 45mm is mandatory? If not, what additional requirements? If so, what is the...

Thanks a lot for your guys' quick response. :)

Hey Folks, What does that mean when vendor mentioned "No Land and with 3/16" Gap" to describe the long seam preparation? Thanks, A Novice

Sorry, wrong click and not finished yet. UW11(a)(2),(4) and (5b) are related to BW on nozzles. So I think if FULL RT (specially RT-1) is specified, BW on large nozzles shall be fully RT. Comments? Thanks, guys.

Hi Folks, As stated in UW11 (a), the FULL RT is specifed for different applications, however, I have some confusion regarding the nozzle. If specified Full RT, does that mean only for vessel shell and head, or should we applied to the BW on nozzles larger than NPS 10", like Category-A long...

Yes, the mean stress has been considered in the fatigue curves of different materials (See the notes). So, no need to shift the curve or play with the Goodman chart any more. Thx.

Hi All, Where can I find the exact requirement for the VT criteria in the Code? I checked Sec VIII, Div 1, Sec V and Sec IX, seems there is NO clear criteria for the visual examination. I mean that if there is quantitative requirements for the imperfection on the welds/seams such as undercut...

Thanks for your comments and especially the good insights in those two old threads. Cheers.

Hey folks, Sometimes we noticed that the requirement of the MAWP limited by shells or heads instead of discontinuities like nozzles is stated either explicitely or indirectly. What do you guys think of it? Please present whatever your thoughts from experiences. Thanks in advance,

nhtien & hjulien, Firstly, I think SA-414 Gr.G shall be a ASME material, and I did find it from the table. Secondly, if design based on stress analysis will be used to evaluate fatigue, please remember Div 2 allowable shall apply. So, even though you could not find the Sm for some materials...

I got the same unfavorable opinions on FCAW in field vessel welding from our clients but there is no exact explaination. Now from your guys' expert post, I learned a lot. Thanks.

My understanding is that intergral or self-reinforced nozzles are most often used in cyclic services. The major reason is less discontinuties and fillet welds etc, which always introduce the higher SCF and peak stress. In addition to the forgings, insert-plate type nozzles are used very often...

Once worked on checking if a pair of nozzles on the transition cone of a tower can be used as "trunnions" for lifting, but it failed from the FEPipe results. So, totally agree with Joe Tank's comments: Can't be too safe.

deanc, The so-called study was actually repetitive work on the local stress analysis around attachments when the piping loading changed again and again from the layout. So I did glean some rules of thumb through FEA though, they were not generalized at all. However, as we know, unless around...

Thanks for your reminding, Joe. I meant higher safety factor 3.5 (revised), but lower allowable stress. Although quite close to div.2 limit (3.0), it still cause substential difference in some particular cases like higher pressure, thicker vessels. Anyway, thanks again.

Doug, If there is no fatigue issue, do not worry about the horrendous peak stress, very localized concentrated stress. However, regardless of what cases, the stress at one spot (either nodal stress or elemental stress) shall NOT be directly compared with the Code Allowable stress at all...

Here below is some experiences about the stress distribution around a reinforced nozzle based on the FE study. Pad or repad, often used to increase the available area as per UG-37, is essentially introduced to redistribute the local bending stress due to the internal pressure or piping loading...