PED vs. ASME VIII -1: Charpy impact requirements

[RONNL]

Since the ASME VIII - 1 Code defines it own set of requirements for the execution of and the minimum toughness values for the impact test, how does these toughness value conflict with the ESR's of the Pressure Equipment Eirective ? Note: In par. UG-84 the ASME VIII - 1 demands minimum toughness values of 20 J, for low yiel strength materials. The latter value is lower than the 27 J criteria in the PED/ESR.

Is it allowed to follow to ASME Code entirely for this matter ductility matter, and one will yet recieve a CE mark under the PED ?

Regards - RonNL

 

[lostsailor]

RonNL,
One of my clients recently fabricated sixteen heat exchangers that were to be stamped ASME "U" and also comply with the PED.
In areas addressed by both, go with the more stringent standard. I've found this to be good practice whenever conflicts of this nature arrive. Consulting with your AI and NB(notified body) would also be a good idea.
Regards,
RLS

 

[rorschach]

The EU seems to love deviating from ASME/ANSI standards just enough to give us Americans fits. Hey, they can't even write a constitution that doesn't run into the hundreds of pages for cryin out loud! They seem to use the same methodology with thier standards too. lostsailor is right, if you stick to 27J, then you are set no matter which place it goes. NOBODY is going to complain here in the US if you exceed the standard. (ok, maybe the beancounters might...)

 

[Cockroach]

The Pressure Equipment Directive applies only to the European Union/Comminity in the sense that one of their governing bodies has exclusive jursidiction on usage of forgein goods. The simple matter of fact is that the document in virtually identical to pre-existing standards in the US or Canada. The slight difference in values reported by each specification, PED verses ASME in your case, is a more conservative factor of safety in Europe.

The PED document is essentially a economic trade barrier to counteract the NAFTA in place in the western hemisphere. If you have a hard time believing that, open up a valve or pressure vessel specification, and put it beside the equivalent EU document. What is even more remarkable, make the metric-imperial conversion. Surprise!

The Europeans perfer to have authority over their own house, not have us tell them what is acceptable the market. The French are particularly bad for this. In Canada, some specifications are recognized since we once formed part of the British Commonwealth and have very similar documentation. CZA 245.15 for Steel Valves is one typical case; API however is problematic. This doesn't mean that API is wrong or useless, it means that the API design code is not universally accepted in Europe, their market.

In order to recieve the CE mark under the PED, you must submit your product, complete with design specifications to a governing European agency, pay the required fees and wait several weeks for a reply. Once accepted, then you grandfather the other product sizes based on similar nature.

Rorschach echos many companies I have dealth with. Remember that America doesn't write specifications that are necessarily globally accepted. That doesn't mean that the product is unsafe, it means that economic trade and market barriers provide individual countries with first right to consumers. In North America, Canada and Mexico both suffer under the NAFTA agreement which is essentially American controlled. Alberta beef, Saskatchewan wheat, British Columbia hydroelectricity (West Coast) or Quebec (East Coast) are good examples.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada