Safety factor changes in ASME VIII Div 2?

[kevlar49]

Since 1965, have there every been changes to the allowable stress safety factors in ASME VIII Div 2? The reason why I ask is that I am trying to apply API 579 Section 3 to develop a Temperature/Pressure envelope for start-up/shutdown of a reactor. According to API 579, if my vessel was made to Div 2, Temperature restrictions must be observed when I surpass the 30% MAWP value (8 ksi level). However, old (pre API 579) original documentation stated that the limit was closer to 25% MAWP but did not explain why.

 

[metengr]

Since 1965, have there every been changes to the allowable stress safety factors in ASME VIII Div 2?

Yes, there have been changes in allowable stress values in ASME B&PV Code Section II as more test data is obtained and more operating expierence with boiler and pressure vessel materials. Are you aware that Section VIII, Division II was completely re-written for the 2007 Edition of the ASME B&PV Code?

 

[kevlar49]

Were the safety factors any lower than 30% in 1965?

 

[EdStainless]

For many materials the factors went from 1:4 to 1:3.5. That is only 12.5%.

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Plymouth Tube

 

[kevlar49]

Sorry, what I meant to say was, was the 8ksi level lower than 30% MAWP before 1965? The material in question is ASTM A387 Gr. D. Sorry I don't have a copy of that code, otherwise, I'd look it up.