JamesBarlow
Mechanical
- Feb 4, 2002
- 186
I have a customer in Canada who has ordered a machine that will have a pressure vessel on it. A small vessel made of 304SS pipe with welded elliptical ends made to Sect 8 Div 1.
In their specs they require we use material values from the 1998 addition of Sect 2 Part D.
My understanding is the difference between the current values and the 1998 revolves around a change in the factor of safety to calculate the strength allowable. 1998 was 4 and the current addition is 3.5. My problem is I can't see where this comes from. For 304SS without the efficiency factory just dividing the ultimate strength by 3.5 does not give the allowable. I have to use 3.75 to make that work.
One of the older guys told me to just multiply the current allowable by 7/8 to get the 1998 values. Given all the hoops the code makes us jump thru this just seems to simple.
Is it that simple or do I need to track down a copy of the 1998 code to find the values.
In their specs they require we use material values from the 1998 addition of Sect 2 Part D.
My understanding is the difference between the current values and the 1998 revolves around a change in the factor of safety to calculate the strength allowable. 1998 was 4 and the current addition is 3.5. My problem is I can't see where this comes from. For 304SS without the efficiency factory just dividing the ultimate strength by 3.5 does not give the allowable. I have to use 3.75 to make that work.
One of the older guys told me to just multiply the current allowable by 7/8 to get the 1998 values. Given all the hoops the code makes us jump thru this just seems to simple.
Is it that simple or do I need to track down a copy of the 1998 code to find the values.
