Dave - Thank you, your article in the newsletter is an enlightening distillation of what goes on out of view within the flexibility matrix analysis with regard to flexibility factors for elbows. I can extrapolate from there for tees if other than k=1 were used.

1. I find it interesting that the 2PD of straight pipe diameters for intersection runs does not also apply to the intersection branch. Would not the flexibility of the intersection be affected by a stiffer element close on the branch as well as close on the run?

2. Do any piping codes (international) use an approach other than von Karman/Hovgaard/Beskin/Markl basis for developing the fatigue stresses in fittings? (That is: for metal piping, not GRP piping.)