ASME EXTERNAL PRESSURE CALCS

[donnajoe]

How should an engineer approach ASME Boiler Pressure Code external pressure calculations that go outside the range of the charts in Fig 5-UHA-28.1? The condition that exceeds this chart for 304H material is 1300F.

 

[prex]

In my opinion if you have to stamp your vessel you can't go beyond the chart limits.
If don't want to comply with the code your only choice is to use the principles of App.3 to ASME II Part D.
However don't forget that your steel will emit some red light at that temperature...
prex
motori@xcalcsREMOVE.com

http://www.xcalcs.com

Online tools for structural design

 

[engrdon]

Due to the elevated temperature, a creep-buckling analysis must be performed based upon an agreed upon life expectancy.

A rough outline of the steps are as follows.

1. Construct a finite element model of the item. (In this case a piping manifold).

2. The material properties used in the model come from ASME Section III, Division 1, Subsection NH Elevated Temperature Design based on temperature and life expectancy.

3. Perform the analysis. The software should be able to determine an allowable external pressure based on strain criteria (generally output as an eigenvalue).

High temperature design criteria are based on strain rather than stress.