is ASME a law?

[Silje]

Hello,

I could read once that ASME is mandatory in America, but somebody told me, that ASME is like a law. You have to work exactly according to ASME. For example, the yield strength for the ASME materials are higher than in the European PED. Could I use a European steel with better (means safer) requirements ? Could I use other formulas if they make the pressure vessel safer?
Greetings Silje

 

[corus]

If you use other forumlae that make the vessel safer then logically you'd have satisfied the requirements of ASME so no problem.

 

[stanweld]

The requirements for ASME are provided State by State (and in some cases by Municiplaity (City) as incorporated into Law. Not all States require adherence to ASME VIII. For practical purposes, all require ASME I. If you manufacture a PV for export to a particular State in the USA and ASME VIII is mandated, you must meet the Section VIII requirements, as a minimum.

 

[TomBarsh]

The yield stress of a material is a physical property. I don't see how this property can vary depending upon what the Code is.

Of course, material specifications are defined under many different systems and there is no assurance that a steel under an ASME material specification is identical to another steel produced to a different specification. But if the two specifications are "equivalent" then the steel itself should have one given yield stress as a physical property. But under ASME Code the minimum yield stress is defined. If I remember correctly, some European standards also define a maximum yield stress in order to assure ductility (the maximum yield stress of the material should not be too close to ultimate).

Also, other things being equal, I would think that a steel product with higher yield stress would be "safer" than one with low yield stress. It's a relative measure of the quality of the material. Advances in metallurgical processing over the past 100 years means that the steels of today have higher yield stress values than older steels, and yet are of better quality, better consistency, and hence "safer". JMO

Regarding ASME as a "law". No, it is a design code, not a "law" in the sense of a legal, regulatory jurisdiction. In North America a number of legal jurisdictions have adopted the ASME Boiler and Pressure Vessel Code as a standard for pressure vessels operated in their jurisdiction: any such vessel must meet ASME requirements. But ASME itself is not a legal jurisdiction and cannot enforce the Code under a legal system (they will enforce it through the Code stamp registration process...you don't comply, you don't get to sell ASME-stamped pressure vessels). For example, in the EU pressure vessels must comply with the PED under the authority of the legislative (law) process. But the PED is not itself a design code, numerous design codes are accepted under the PED.

 

[metengr]

ASME Boiler and Pressure Vessel Code is not considered law, it is one of several internationally recognized Codes and Standards that provide requirements for design and fabrication of boilers and pressure vessels for safe and long term operation. If a design code is adopted within a country, Jurisdiction or municipality, it becomes enforceable. Yes, you must work within the requirements of ASME to stamp the vessel or to codify it.

 

[gr2vessels]

Silje,
When designing a pressure vessel, you have to use a valid, internationally recognized standard, for eg. EN 13445, ASME VIII, PD 5500, etc.
When using one of the applicable codes, you have to use the yield stress and the allowable design stress specified in that code/standard. You cannot however, mix and match the formulas from one code and yield values from another code. There could be some exceptions (very few) allowed in the code, but those have been justified and checked for conformance.
Cheers,
gr2vessels

 

[steris]

Many states and municipalities require compliance with ASME however some of them will grant an exception and accept other certifications (PED others) with prior notification/approval from the chief boiler inspector.