two items of possible concern:
1. The thicker ell decreases the flexibility of the piping system which could potentially result in higher stresses and/or higher loads on branches and equipment nozzles.
2. The smaller ID of the ell will increase pressure drop through the system.
In...
To add one other comment: When I referred to "thickness" I meant the overall thickness of a component, not the local thickness in a confined area such as due to a corrosion lake or pitting.
LSThill, Thanks for your reply. I viewed the presentation but it did not answer my previous question. I should explain too that my question was asked in the context of not using FFS to keep the equipment operating until it can be repaired, but rather using it to supersede Code of Construction...
An existing, in-service vessel was originally constructed and stamped to ASME Section VIII, Division 1. Various nozzles do not meet the UG-45 requirements in effect at time of fabrication nor the same requirements which are currently in Table UG-45. The vessel now falls under the jurisdiction...
API-510 contains requirements for the rerating of pressure vessels. At a facility where I work the owner has adopted this as the governing document for rerating of pressure equipment previously built to both ASME and API-ASME Codes.
As pointed out by SnTMan rerating involves all pressure...
TGS4,
Thanks for your replies. I appreciate your suggestion about forwarding this issue to ASME.
The owner has performed an API-579 Level 2 assessment and has concluded that the vessel is suitable for the -150F design temperature. I spent some time looking through API-579 but I could not...
gr2vessels,
Thanks for your response. It seems reasonable, however, is there anything in technical literature to support your recommendation?
To answer your guestion, the vessel was originally impact tested at -55F. Only during infrequent upset conditions would it be possible for the vessel...
These type of problems are difficult to comment on without seeing a drawing and knowing all of the particulars of the design. However, lacking the preceding, one alternative is to use a 90 or 45 degree ell and trim it to the appropriate angle and weld it into place. The trimmed fitting, when...
An existing carbon steel vessel, which was not impact tested, is being evaluated for suitability. Desired MDMT is -150 F. When operation will occur at this temperature general membrane stresses are such that the ratio as shown in Figure UCS-66.1 is less than 0.35.
Local stresses at nozzles...
An existing carbon steel vessel, which was not impact tested, is being evaluated for suitability. Desired MDMT is -150 F. When operation will occur at this temperature general membrane stresses are such that the ratio as shown in Figure UCS-66.1 is less than 0.35.
Local stresses at nozzles...
Two existing girth flanges are mated together. One flange has a nubbin 1/64” high and 1/8” wide. The gasket used between the flanges is DJAF iron, that is 1/2” wide.
Question:
When considering the facing on the flanges as Type 2 (per Table 2-5.2, from Sec VIII, Div 1, Appendix 2), the joint...
Recent Code Editions have included a new factor, termed "W" (Weld Strength Reduction Factor), to be included in thickness and other calculations. The factor is the same for all materials although the Code provides latitude in this regard if other data is available to the user.
Is anyone aware...
Stanweld,
Thanks for your input. PWHT temperature was 1400F +-25F with minimum 2 hour hold time. Ramp up was 50F per hour above 300F. Ramp down was 300F per inch per hour from PWHT temperature to 300F.
stanweld,
Thanks for your response. P9 material would not provide the required elastic and rupture strengths at the required design conditions and thickness. In essence, it was not a cost effective choice.
metengr
Thanks very much for your reply. Based on past experience it doesn't appear that hardnesses below 190 will occur. However, I reviewed previous NDE reports and noted that approximately 50% of the post PWHT readings for the weld metal exceeded 250 BHN. The highest was 270 BHN. Base...
For the weld and HAZ of ASTM A-335 P91 material, ASME B31.3 recommends a maximum hardness of 241 BHN. However, NACE MR0103 appears to allow a maximum of 248 BHN for the base metal, weld, and HAZ.
For seamless fired heater tubes in hydrocarbon service, which contain circumferential welds...
Can anyone suggest a method or provide data for determining allowable compressive stress for a cylinder of specific geometry operating at a temperature above the limits in ASME Section II, Part D, Subpart 3?
The specific application would be a tall column constructed of SA-516-70 material...
