This not exactly a Caesar question. But I am posting as there might be enough help available here-
B31.3 refers to ug-28,29 of pressure vessels code for vacuum design of piping.
However ug-28,29 strictly deal with pressure vessels and therefore some of the piping situations are not well covered.
For example elbows or change in direction is not addressed in ug-28,29.
While looking at a piping system and trying to figure out whether additional stiffening rings are required, how should we treat elbows?
The way I am looking at it is: every change in direction represents a stiffener at the end of straight pipe, similar to head of a pressure vessel as illustrated in ug-28,29.
Therefore,if the length of straight run between two elbows satisfy the requirement of max. length without stiffener, then no stiffener will be provided. The point that I am trying to make is : I do not have to add the length of pipe in perpendicular direction to get to the next saddle support or a rigid element.
Please comment.
_________________________
Stress