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I think the paper by H.C. Boardman in 1943 “Formulas for the design of cylindrical and spherical shells to withstand uniform internal pressure” was the basis of the UG-27 equation. The paper started with classical equations, which had been used in Appendix 1-2 of Div 1 Code up to 2007 Edition...

If the skirt is not continuous welded, and bottom head is insulated, how do you prevent rain water getting into insulation? All the specs I have seen requires continuous weld at skirt attachment if the specs cover the subject

I don't know why you did normalizing after cold forming. I typically see normalizing during hot forming or after hot forming. Either way, weldtek's interpretation is clear and correct. If you already have the MTR for normalized plates from the mill, you don't need to run test coupons again.

I see some confusions here between the Quench and Tempered materials covered under UHT section of the Code and regular P1 materials in Q&T condition. They are different. There are no special fabrication requirements for regular P1 materials (such as SA-105 or SA-350) in Q&T conditions. I think...

If the equipment is in hydrogen service, you don't want to use carbon steel at 465 deg C. It may be OK for 465 deg F, but definitely not OK for 465 deg C. Go check API 941.

If you don't care if the plates are normalized, it is better to specify SA-516 only. Vendor can choose to buy as rolled plates with impact test or normalized plates to get away with impact test, whichever is more convenient and economical.

Order normalized will give you Curve D.

Of course I was talking about carbon steel vessels in wet sour service. Once the vessel is cladded, there is no need for base material chemistry control, PWHT, hardness control, etc. If we are talking about identifying defects that are related to wet sour servce, WFMT is a more effective...

I would like to know how full RT can prevent failure from wet sour service. If we are talking about criticality, you can apply that to any vessel, no matter it is in wet sour service or not. To me the more relevant NDE for wet sour service vessel is WFMT on all internal welds after PWHT.

For B16.5 flanges, plate material can only be used for blind flanges.

You can use plate material such as SA-516 70 for tubesheet as long as client spec does not require forging only. If the tubesheet has hub, see Appendix 20 of the Code.

I agree that you may be able to stamp the bolting material as SA-320 L7M. However I am not sure you can use it on a ASME Div 1 vessel. According to UG-4(e), you can use a material outside of size /thickness limit of a material spec assumuing there is no size/thickness limit given in the stress...

I agree with TGS4. I think jtseng123's opinion on nozzle load analysis is little out of date. Several papers have been published by vessel engineers since 8-9 years ago to not use the sustained / thermal classifications in B31 codes on vessel nozzle load analysis. They suggested treating...

I think the vendor was misusing the Miner's rule. If the load cases are indeed acting simultaneously, what the vendor was doing would underestimate the damage. A 200 ksi alternating stress intensity would do much more damages in 100 cycles than (2) 100 ksi stress intensity acting consecutively...

I don't have access to the 1966 code edition. In the old days, ASME Code did not have UW-11(a)(5)(b) requirements for seamless heads. So if the head was seamless, then E=1.0. You would need only 0.4" thick head if E=1.0.

My understanding is longitudinal stiffeners does not have much use for external pressure (vacuum). Circumferencial stiffener rings are very efficient for external pressure, but not very good for bending or axial compression. Longitudinal stiffeners are mostly used in marine structure. You can...

It is common to run into a situation jtseng123 described when you use dissimilar materials on one vessel. For example, before the Code made revision in UG-99 several years ago, it was common to have bolting material for custom designed body flange limiting hydrotest pressure. Hydrotest can be a...

jtseng123, Refer to UCS-68(c) for PWHT and impact test exemption temperature reduction.

How about design the nozzle reinforcements to (DP + 1 psi)? This can be easily done by increasing some weld sizes. Then tell your client that the vessel MAWP is not limited by nozzle reinforcement, but limited by their spec.

It should be in para 3.4.2 of NBIC. It is the year of 1968, not 1965.