Allowable Stress

In piping and B&PV code the term "Allowable stresses" always comes up. IGot more confusing, since the Code also throws up one for pressure and another for thermal expansion.

         In the tradition of "for dummies book series", what is the allowable stresses?

         The real fun begins when the Code permit the allowable stress for pressure design to be exceeded. This has confusesd a lot of piping designers. What is really the Code saying about this. An illustration will be much appreciated Received on Mon Aug 27 04:41:00 2001