Thanks, SteveBraune.
Used to be a stress engineer dealing with Div 2 and Section III for years, so more interests in the design by analysis philosophy. According to your comment, BS5500 is equivalent to Div 2 or Section III of ASME, right?
zjliang,
I guess I was thinking more along the lines of allowable stresses and design results. BS-5500 had much higher allowable stress values than Div 1... much more like Div 2. But those observartions are from many years ago. Sorry to have gotten you off track on this.
PD5500 is essentially EN 13445. As Steve pointed out it is similar to Div.2
To give the quick answer to your question the general differences between PD 5500 and Div 1 and similar to the differences between Div. 1 and Div. 2.
In some cases, PD 5500 allows higher stresses than Div. 2. Duplex stainless is a good example of this. For example, 2205 can have an allowable tensile stress of greater than 31000 psi at 175C. Vaccum is handled differently than ASME.
PD5500 has tighter tolerances than ASME. For example, maximum out-of-roundness for external pressure is 0,5% but it is not measured based on Dmax - Dmin. Vessels exceeding this can be analyzed to see if they are acceptale. However, if the peaking values in PD5500 are exceeded additional engineering is not permitted to make the vessel acceptable. I've just been through a case with a large (10 m diameter) pressure vessel where both of these issues had to be addressed.
PD5500 also has more fabication tolerances than the ASME codes. maximum deviations of nozzles from tangent lines are specified.
There can be greater NDT requirements.
I know this is slightly off what you are looking for but differences in design rules and allowables also have a price which often is not seen.
