And one more thing...

Over all the years of doing this work I have had numerous times when piping, or equipment was overloaded when analyzed, and yet the new work which I had just analyzed closely matched an existing installation which all the knowledgeable people using it said "it works just fine"

So what gives?

In some cases the people saying that everything was fine are flat out ingnorant and wrong. An example of this is an owner who said that his pump seals lasting nine months between failures were fine... whereas actual MTBF for that set of seals should have been 3 years!

In the case of static equipment don't forget that thermal overloads are fatiuge based and will take many cycles to have their effect, and if they do cause a crack its is most likely that the crack will be blamed on bad fabrication as opposed to ****py design.

Also for the final fact to ponder on... every good engineer applies a safety factor to their work. The B31 codes build various factors of safety into our work. The same is true I'm sure of other codes as well. As also is the allowable loadings for rotating equipmment. If the over load is small enough "eating" into this factor of safety has no negative effects but, it may. So a design which is slightly over may work out by blind stupid luck.

------------------
Best Regards,

John C. Luf