This refers to final remarks of L.C.Peng's recent writing in Feb'06 issue of Chemical Engineering on the topic of hot sustained run:
"The first priority of the analysis is to accurately determine the sustained weight stress at hot operating condition. This is not to say that expansion stress is unimportant. A good analysis shall calculate as accurately as possible both sustained and expansion stresses."

Now, my question is : although we have vessel nozzle load allowables generally apportioned in 1:2 for dead weight:thermal expansion load, how many of us meet this division religiously ?

Mostly, we meet the whole allowable under any possible operating condition - sustained load & hot operating load - isn't it ?

Even in WRC-107 or Nozzlepro/FePipe check, sustained & expansion load allowables are different as per ASME SEc-VIII Div-2 Elastic Analysis.

regards,

sam