This update does not effect material, gasket, or other files that are typically customized by RCS users. Nonetheless, it is always a good idea to make a complete backup of your RCS install by creating a copy of the entire RCSWin folder and all files in it. This ensures you will be able to resort back to the previous version should any problems with the install arise.
Note: To get a printout of all instructions, program and file updates, enhancements, and corrections from within RCS, go to Tools->Administrative and double click on Edit / Print updates. Note that this displays the last few updates in sequence.
Appendix 1-5 and 1-8 Cone Reinforcement Requirements (a) In the 2013 Code, modifications were made to the methods for calculating required and available reinforcement for eccentric and concentric cones due to internal and external pressure. If the cone is attached to a cylinder at the large and/or small ends, then the cylinder now must be a minimum length to be considered available for reinforcement.
(b) In addition, you may no longer consider hubs on a flange welded to the cone, hub on a tubesheet, straight flange on a head or any other component, towards this length.
(c) The program will calculate and display the minimum cylinder length as soon as you enter the radius and thickness of the cylinder at the appropriate location. You will be warned if your cylinder is too short to consider (or you do not have one), and allowed the opportunity to change that.
(d) Calculations are then performed in accordance with one of two procedures as dictated by Appendix 1-5 and 1-8.
(e) The program has been modified such that if you are designing a kettle reboiler and select the option for "Cone With Stub" the program will default the stub cylinder length at the small end to the greater of 6" or the length required to meet the minimum length requirement of App. 1-5 & 1-8.
(f) While making changes to the cone programs to accommodate the App. 1-5 & 1-8 changes, a number of other improvements were made as well. Cone calculations can now all be printed or viewed in English or Metric format, where they only worked in English before. This includes standard cone thickness calcs and cone reinforcing ring calcs for both internal and external pressure. In addition, units have been added to the cone screen printouts. The standard toggle between English and Metric units on the data input screens now works properly for all cone screens. Finally, the help descriptions for all cone input fields have been significantly improved.
UHX Tubesheet Program (a) Variables for minimum pressures Tube side and Shell side were added in the 2013 edition of the Code. These variables are Ptd,min and Pts,min. However, UHX defines these variables as "negative if vacuum is specified, otherwise zero". RCS already had variables to allow for application of vacuum cases labeled "Negative pressure Shell" and "Negative pressure Channel". Therefore, these variables were simply renamed to match the new ASME Code definitions. The addition of the two fields described above was not necessary and has been eliminated.
(b) Existing cases you have run will not be affected by this change, nor are they incorrect. If you were still utilizing the fields labeled for "Negative Pressure" then the program used those entries in computing the necessary load cases to be analyzed. If you were utilizing the new fields Ptd,min and Pts,min to indicate the vacuum conditions, then the program used these instead.
(c) In the 2013 Code edition, UHX also added two variables to indicate the operating pressure on the shell side and tube side. These are labeled Psox and Ptox. These variables are only utilized for cases that involve "Operating Conditions". Generally that means any case that includes the effect of differential expansion.
(d) The same variable locations that were previously used to input the minimum design pressure for the shell side and the tube side are now "repurposed" for the operating pressures. PLEASE TAKE NOTE: Commonly these fields would be zero previously, when utilized for the minimum design pressure. They SHOULD NOT be zero any longer. Please enter the appropriate operating pressures for each side. Recognizing that the possibility exists that you may have an operating pressure of zero (however unlikely) the program will allow you to enter a value of zero. As a precaution the program pops up a warning message to alert you to the fact that you have input an operating pressure of zero and asks if that is truly your intention.
(e) Paragraph UHX-10(f) (last sentence) states: "If the operating pressure is not available, the design pressure shall be used for all loading cases." Thus it is acceptable to use the full design pressure for situations where the operating pressure is not known.
(f) CAUTION: It may seem "conservative" to utilize the design pressure for both fields all the time, since the design pressure is higher. However, this is not always the case. A common example would be a high pressure channel with tubes that were expanding more than the shell. The differential expansion of the tubes is trying to bow the tubesheet "into" the channel. The channel pressure, however, is trying to bow the tubesheet "into" the shell. These two effects, when considered simultaneously, tend to offset each other and may result in a relatively thin tubesheet. If a lower pressure were in play inside the channel (such as the operating pressure) it would not necessarily offset the differential expansion stresses quite as much and result in a thicker tubesheet. This is only one scenario of many that could be conceived in the design. The addition of these variables seems to be ASME's way of addressing this potential.
(g) An enhanced summary printout is now included as part of the UHX calculation printout. This summary appears at the end of the UHX printout. Previously, there was a short summary, simply stating if each case was acceptable or not. Now the program provides a summary of just the stresses, along with their respective allowable stresses and a percentage that each is of the allowable, for each case. This summary allows you to quickly determine which case (or cases) failed, and / or which case controlled the actual final tubesheet thickness. This is particularly useful if you have a tubesheet that welds to one or both of the channel or shell. If the channel or shell stress was actually the controlling value, then it is easy to spot and you may want to consider thickening up that cylinder in order to thin down the tubesheet.
Zick analysis for support saddles (a) An error has been corrected in the RCS Zick program. The program can be accessed by clicking Run -> Utilities -> L.P. Zick. The program structure remains the same, but an error in one equation has been corrected.
Support Saddles (a) There was a formatting issue on the support saddle printout. The printout has been fixed to allow larger values for the moment of inertia. When running large, heavy exchangers, the moment of inertia field on the printout would sometimes exceed the size allotted for it, resulting in the values not being printed at all. This problem has been corrected.
RCS Help (a) The help system built in on many of the RCS screens previously used F8 and / or F9 for access to help information. While these options are still supported and will work correctly, we have modified the RCS menu system to use the more conventional Windows standard of F1 for help. This applies to virtually all of the RCS programs.