Reviewing SIF at Dummy Leg Intersections

C2 has a provision of reviewing SIF's at Intersections of Dummy legs.

In most cases dummy legs are taken from Elbows.

E.g An elbow at Node 10 (12" NB Main Pipe) with Midpoint at Node 9. Node 9 is the intersection(Start point) for a dummy of 6" NB (Branch Pipe).

On reviewing SIF Spreadsheet for Intersections at Node 9 shown as default by C2 cal, Header OD appears to be 6" NB and Branch OD also appears to be 6" NB. The default type of intersection taken by C2 is Unreinforced.

Do let me know whether the SIF's thus generated can be taken for cal.

I beleive the User needs to recalculate such intersection by changing the Header OD to 12" NB & related Header Thk. and keep the Branch Header to 6"NB with its relevant Branch Thk.

Please advise the correct procedure for such intersections.

Also advise whether the SIF thus generated can be used as enhanced SIF's at Dummy intersections.

The Intersection Scratch-Pad built into the Piping Preprocessor assumes you're dealing with a 90^o tee, as defined the piping codes. This Scratch-Pad should not be used for dummy legs on bends.

To evaluate the SIFs for dummy legs on bends you should use the option SIFs @ Bends off of the Analysis menu. It is in this utility that you can specify the bend pipe size and the trunnion size.

The SIFs obtained here can then be used as input, back in the Piping Preprocessor. Note, to specify the SIF on the dummy leg, go to that element, then check the checkbox for "SIFs & Tees", leave the intersection type blank, and specify the SIF values. To override the SIFs for the bend, go to that element, check the checkbox for "SIFs & Tees", leave the intersection type blank, and specify the SIF values. (To avoid this causing an error in the Error Checker, you need to modify the Configuration to allow user defined bend SIfs.)