For "large openings" analyzed per ASME Code Section VIII, Division 1, 2007 Edition and later, COMPRESS analyzes the opening by either of the following methods. Note the further discussion below about the weld path strength requirements of UG-41.

Method A:

• Check by UG-37 and Appendix 1-7(a) area compensation rules.
• Perform Appendix 1-7(b) stress analysis if required by that paragraph.

Method B:

• Perform stress analysis using Appendix 1-10 stress analysis method (which is more comprehensive than the stress analysis of Appendix 1-7(b)). Note that the stress analysis method of Appendix 1-10 is used in lieu of the area compensation principles of UG-37 and Appendix 1-7(a).

Note that both Appendix 1-7 and Appendix 1-10 have limitations on the range of sizes and types of construction to which they may be applied. If a nozzle falls outside of these restrictions then COMPRESS will use the rules of Division 2, Part 4.5 for the nozzle analysis, under the direction of Division 1, paragraph U-2(g).

The designer can elect to use either the Appendix 1-7 method or the Appendix 1-10 method: Edit the nozzle and click the "Areas" button; then select the desired method on the dialog:

Appendix 1-7 has a number of limitations on the applicable geometry. COMPRESS automatically applies Appendix 1-10 if Appendix 1-7 is selected but the nozzle geometry falls outside the scope of that Appendix. If the nozzle geometry falls outside of the Code limitations on applicability of Appendix 1-10 then COMPRESS uses the rules of Division 2 Part 4.5 under the provision of Division 1 paragraph U-2(g). In this latter case there is no need for a Division 2 Code stamp, etc.

See further discussion in the COMPRESS History document (select the COMPRESS Help menu, select "View History" command; search the document for the entry for build 6255):

(14) Appendix 1-10: A new alternative method is now available to evaluate large openings in cylinders and cones. The designer can designate the analysis method globally on the Nozzles 1 tab of the Set Mode dialog or on an individual nozzle basis under the Areas option button in the Nozzle dialog. The new method provides a direct calculation of the maximum local primary membrane stress at the nozzle intersection (PL) by using a modified pressure area method to determine the magnitude of the discontinuity force resisted locally. Division 2 Part 4.5 is utilized to evaluate the strength of attachment welds as the UW-41 analysis is not applicable. It should be noted that the 2007 Edition of Division 2 uses this method for the design of all nozzles (all Rn /R ratios and nozzle configurations). For nozzle configurations that are not covered under Appendix 1-10 (eg. hillside nozzles in cylinders), Division 2 Part 4.5 is used as a U-2(g) analysis.

Note that the title of Appendix 1-10 refers to "Alternative Method of Design of Reinforcement"; thus it is intended as an alternative method of analysis, not a new additional requirement.