Some screen shots and questions (AutoPIPE SELECT series 5 Edition 9-1902015) .1) For code B31.1 2007 (Default load combination created by Autopipe)
Effect of pressure is included in Sustained load case.2) For code ND 2007 (Default load combination created by Autopipe)
Q. Why sustained load doesn't include pressure load?
ASME Nuclear default code combinations are always a single load case combinations because the Nuclear codes follows a different program path, the concept of Stress Summaries. Through Stress Summaries the program internally takes care of the pressure term using the correct value (i.e. Design Pressure or Load Case Pressure P01..Pn) in the respective Service Level set of equations. The stress summary reports the details and results about each equation (ex. 8, 9 10 ets.).
For details about the Service Level and coincident equations, please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations> ASME BPV-III-1-ND (1972 - 2013)
1. Stresses Due to Sustained Loads (Equation 8).
See AutoPIPE help for the detailed equation, note that the "P" value in this equation represents Internal Design Pressure. This Design Pressure value would be taken from the respective node point on the "Design Press/Temp" tab of the input grids. .
2. ND - Stresses Due to Occasional Loads (Equation 9)
Where as this equation calls for Pmax. This value is taken as the maximum value across all pressure load cases P01.Pn from "Pressure/ Temp/Pipe ID" tab of the input grid.
3. Disable / Enable Pressure Extension under Static Analysis sets:
4. ND - Sustained Loads & Thermal Expansion Requirement (Equation 11)
Eq. 11 is dealt with differently. It can only have thermal cases, and thermal case will have its associated pressure if required
Again, AutoPIPE evaluates each load case independently before considering them all together in the code stress summary. A pre-verification report of the results from each load case is produced and then the full verification stress is produced, accounting for the load cases category and how it relates to the other load cases.
ASME BPV-III-1-ND, AutoPIPE Nuclear Piping Code FAQ