Flanged end modifications using B31.3
Modifications resulting from flanged ends are permitted in the code providing the bend is not a widely-spaced miter.
Calculate stress intensification factors (SIFs) for intersections using B31.3
In-plane and out-plane SIFs for intersections are separate and unique.
B31.3 piping code gives the equation for the expansion stress. Because that equation does not include the longitudinal stress due to axial loads in the pipe, CAESAR II does not include the F/A component of the stress in the expansion stress equation. The code also says that you can add the F/A component where it is significant. Change this by including the Add F/A In Stress option in the setup file. The F/A longitudinal stress components are added by default to the code stress component for all other stress categories.
B31.3 girth butt welds default value
The default SIF value for a girth butt weld is 1.0. This is also Markl’s original basis for SIFs.
Calculate socket welds using B31.3
B31.3 makes no distinction between socket welds with undercut and socket welds without undercut. Unless you are specifying a fillet weld leg length, use a default SIF value of 1.3 for all B31.3 socket welds.
B31.3 2014 uses 1.3 for socket welds with no undercut. The software provides 2.1 as a legacy value for calculations based on earlier versions.
Calculate the B31.3 stress allowables
Use the equations below to calculate the stress allowables.
Expansion Allowable = f [ (1.25)(Sc+Sh) - Sl ]
Sustained Allowable = Sh
Occasional Allowable = Sh * (Occ)
Where:
f = Cyclic Reduction Factor
Sc = Cold Allowable Stress
Sh = Hot Allowable Stress (as selected)
Sl = Sustained Stress
Occ = Occasional Load Factor Default is 1.33
Calculate corroded stress using B31.3
By default, B31.3 applies corrosion to section modulus calculations for sustained and occasional stress calculation. Specifying All Stress Cases Corroded in the setup file performs the corroded stress calculations for all stress calculations.
Calculate pressure effects on miters using B31.3
Pressure effects on miters are allowed in the B31.3 piping code.
B31.3 reducer default values
The default SIF value is 1.0. The default flexibility factor value is 1.0.